Document:

EX-4.5

 Exhibit 4.5 

THIS WARRANT AND ANY SECURITIES ACQUIRED UPON THE EXERCISE OF THIS WARRANT HAVE BEEN ACQUIRED FOR INVESTMENT AND HAVE NOT BEEN REGISTERED UNDER APPLICABLE
U.S. OR NON-U.S. SECURITIES LAWS. NEITHER THIS WARRANT, SUCH SECURITIES NOR ANY INTEREST THEREIN MAY BE SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED EXCEPT IN ACCORDANCE WITH THE PROVISIONS OF REGULATION S OF THE SECURITIES ACT, UNDER THE REGISTRATION
PROVISIONS OF THE SECURITIES ACT OR PURSUANT TO AN EXEMPTION FROM REGISTRATION UNDER THE ACT. HEDGING TRANSACTIONS INVOLVING THIS WARRANT, SUCH SECURITIES OR ANY INTEREST THEREIN MAY NOT BE CONDUCTED UNLESS IN COMPLIANCE WITH THE SECURITIES ACT.

 THE SALE, ASSIGNMENT, HYPOTHECATION, PLEDGE, ENCUMBRANCE OR OTHER DISPOSITION AND VOTING OF ANY OF THE SHARES OF CAPITAL STOCK OF THE COMPANY ACQUIRED
PURSUANT TO THE EXERCISE OF THIS WARRANT ARE RESTRICTED BY THE TERMS OF THE THIRD AMENDED AND RESTATED STOCKHOLDERS’ AGREEMENT, DATED AS OF JUNE 10, 2008, AS AMENDED OR AMENDED AND RESTATED FROM TIME TO TIME, AMONG THE COMPANY AND CERTAIN OF
ITS STOCKHOLDERS. THE COMPANY WILL NOT REGISTER THE TRANSFER OF SUCH SHARES OF CAPITAL STOCK ON THE BOOKS OF THE COMPANY UNLESS AND UNTIL THE TRANSFER HAS BEEN MADE IN COMPLIANCE WITH THE TERMS OF THE STOCKHOLDERS AGREEMENT, A COPY OF WHICH WILL BE
PROVIDED AT NO COST TO THE HOLDER HEREOF UPON WRITTEN REQUEST TO THE COMPANY. 
  

 
 ASPEN AEROGELS,
INC. 
 CAPITAL STOCK PURCHASE WARRANT 
  

 
 This document
(this “Warrant”) dated as of June 10, 2008 certifies that, for good and valuable consideration, Aspen Aerogels, Inc., a Delaware corporation (the “Company”), grants to
[                    ] or any successor or permitted assign of such Person (the “Warrantholder”), the right to subscribe for
and purchase from the Company, on or before the Expiration Time (as defined below), up to [                    ] validly issued, fully paid
and nonassessable shares of Common Stock of the Company (as may be adjusted, the “Warrant Shares”) at the exercise price per share of $0.001 (the “Exercise Price”). Capitalized terms used herein which are not
specifically defined in other sections of this Warrant, shall have the meanings set forth in Section 10. 
 1. Warrant
Term. Subject to the provisions of Section 2.4, the purchase rights represented by this Warrant are exercisable, in whole or in part, at any time and from time to time, from and after the Warrant grant date and on or prior to
June 10, 2016 (the “Expiration Time”). 

 2. Exercise of Warrant; Payment of Taxes.  

2.1 Exercise of Warrant. The purchase rights represented by this Warrant may be exercised by the Warrantholder, in whole or in
part and from time to time, by the surrender of this Warrant (with a duly executed notice of exercise form, the “Exercise Form”, in the form attached hereto as Exhibit A) at the principal office of the Company and by the
payment to the Company of an amount equal to the then applicable Exercise Price per share multiplied by the number of Warrant Shares then being purchased. The Warrantholder shall be deemed to have become the holder of record of, and shall be treated
for all purposes as the record holder of, the Warrant Shares represented thereby (and such Warrant Shares shall be deemed to have been issued) immediately prior to the close of business on the date or dates upon which this Warrant is exercised. 

2.2 Warrant Shares Certificate. A stock certificate for the Warrant Shares specified in the Exercise Form shall be delivered to
the Warrantholder within five (5) Business Days after receipt of the Exercise Form by the Company and payment by the Warrantholder of the aggregate Exercise Price, along with a check from the Company in lieu of any fractional shares that the
Warrantholder would be entitled to purchase under this Warrant. If this Warrant is exercised in part, the Company shall, at the time of delivery of the stock certificate, deliver to the Warrantholder a new Warrant evidencing the right to purchase
the remaining Warrant Shares, which new Warrant shall in all other respects be identical to this Warrant. 
 2.3 Payment of Taxes.
The Company shall pay all expenses, taxes and other governmental charges with respect to the issuance or delivery of the Warrant Shares, unless such expense, tax or charge is imposed by law upon the Warrantholder. 

2.4 Exercise or Termination upon Corporate Event. If the aggregate Exercise Price, as of the consummation date of any Corporate
Event, is equal to or greater than the aggregate value of the securities, cash and other property that would have been received in connection with a Corporate Event by a holder of the number of shares of Common Stock for which this Warrant was
exercisable immediately prior to such Corporate Event (the “Exercise Proceeds”), then this Warrant shall automatically terminate upon the consummation of such Corporate Event. If the aggregate Exercise Price, as of such consummation
date, is less than the aggregate value of the Exercise Proceeds, then the Warrantholder shall be entitled to exercise this Warrant in connection with such Corporate Event and shall automatically receive upon the consummation of such Corporate Event,
in lieu of the Warrant Shares, the Exercise Proceeds, and this Warrant shall automatically terminate in connection therewith. 

3. Restrictions on Transfer; Restrictive Legends.  

3.1 Restrictions on Transfer. This Warrant and the Warrant Shares issuable upon exercise of all or part of this Warrant are
unregistered securities that are subject to the restrictions on transfer imposed by the Securities Act and applicable state securities laws and may not be offered, sold, transferred, pledged or otherwise disposed of, in whole or in part, to any
Person other than in accordance with the Securities Act and applicable state securities laws. The Warrant Shares issuable upon exercise of all or part of this Warrant are also subject to additional restrictions on transfer set forth in the
Stockholders’ Agreement and may not be offered, sold, transferred, pledged or otherwise disposed of, in whole or in part, to any Person other than in accordance with the Stockholders’ Agreement. As a condition to the exercise of this
Warrant and the purchase of the Warrant Shares, the Warrantholder will become a party to the Stockholders’ Agreement pursuant to the form Joinder attached thereto. 

  
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 3.2 Restrictive Legends. Until such time as the restrictions on transfer imposed on
this Warrant by the Securities Act and applicable state securities laws shall no longer be effective, this Warrant, any Warrant issued to the Warrantholder upon the partial exercise of this Warrant pursuant to Section 2 shall be stamped
or otherwise imprinted with a legend in substantially the form as set forth on the cover of this Warrant. Until such time as the restrictions on transfer imposed on the Warrant Shares by the Securities Act, applicable state securities laws and the
Stockholders’ Agreement shall no longer be effective, each stock certificate for Warrant Shares and each stock certificate issued upon the direct or indirect transfer of any such Warrant Shares shall be stamped or otherwise imprinted with a
legend in substantially the form provided in the Stockholders’ Agreement. Upon the termination of such restrictions on transfer, the Warrantholder may require the Company to issue a Warrant or a stock certificate for Warrant Shares, in each
case without a legend, if and to the extent permitted by, and in accordance with, the Stockholders’ Agreement and applicable law. 

3.3 Lock-Up. The Warrantholder agrees not to effect any sale or distribution of Warrant Shares during the seven (7) days
prior to and the one hundred eighty (180) days after any Public Offering or such longer period as may be prescribed at such time. For purposes of this Warrant, “Public Offering” shall mean an underwritten public offering
pursuant to an effective registration statement under the Securities Act of 1933, as amended, covering the offering and sale by the Company of Common Stock. 

4. Reservation and Registration of Warrant Shares. The Company covenants and agrees that during the period within which the
rights represented by this Warrant may be exercised, the Company shall at all times have authorized and reserved, for the purpose of issuance of Common Stock upon any exercise of the purchase rights evidenced by this Warrant, and shall keep
available free from preemptive rights, a sufficient number of shares of its Common Stock to provide for the exercise of the rights represented by this Warrant. 

5. Anti-Dilution Adjustments. From and after the date hereof and until the Expiration Date, notwithstanding the fact that no
Warrant Shares shall be issued and outstanding, the Exercise Price, and the number and type of Warrant Shares or other securities to be received upon exercise of this Warrant, shall be subject to adjustment as follows: 

5.1 Stock Dividends and Combinations.  

(a) If, at any time after the date hereof, the number of shares of Common Stock outstanding is increased by a stock dividend payable in
shares of Common Stock or by a subdivision or split-up of shares of Common Stock, then, following the record date for the determination of holders of Common Stock entitled to receive such stock dividend, subdivision or split-up, the Exercise Price
shall be decreased and the number of shares of Common Stock issuable on exercise of this Warrant shall be increased in proportion to such increase in outstanding shares. 

  
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 (b) If, at any time after the date hereof, the number of shares of Common Stock outstanding
is decreased by a combination of the outstanding shares of Common Stock, then, following the record date for such combination, the Exercise Price shall be increased and the number of shares of Common Stock issuable on exercise of this Warrant shall
be decreased in proportion to such decrease in outstanding shares. 
 5.2 Recapitalization, Etc. In the event of any capital
reorganization of the Company, any reclassification of the stock of the Company (other than a change in par value or from par value to no par value or from no par value to par value or as a result of a stock dividend or subdivision, split-up or
combination of shares), or any consolidation or merger of the Company, this Warrant shall after such reorganization, reclassification, consolidation or merger be exercisable for the kind and number of shares of stock or other securities or property
of the Company or of the company resulting from such consolidation or surviving such merger to which the holder of the number of shares of Common Stock deliverable (immediately prior to the time of such reorganization, reclassification,
consolidation or merger) upon exercise of this Warrant would have been entitled upon such reorganization, reclassification, consolidation or merger. The provisions of this clause shall similarly apply to successive reorganizations,
reclassifications, consolidations and mergers. 
 5.3 Computations. The computations of all amounts under this
Section 5 shall be made assuming all other antidilution or similar adjustments to be made to the terms of all other securities resulting from the transaction causing an adjustment pursuant to this Section 5 have previously
been made so as to maintain the relative economic interest of the Warrants vis à vis all other securities issued by the Company. 

5.4 Par Value. The Company shall take or cause to be taken such steps as shall be necessary to ensure that the par value per
share of Common Stock is at all times less than or equal to the Exercise Price. 
 6. Transfer and Exchange. If this
Warrant is presented to the Company with a request to register a transfer or to exchange it for an equal number of Warrants of other denominations the Company will do so. 

7. Loss or Destruction of Warrant. Subject to the terms and conditions hereof, upon receipt by the Company of evidence
reasonably satisfactory to it of the loss, theft, destruction or mutilation of this Warrant and, in the case of loss, theft or destruction, of such bond or indemnification as the Company may reasonably require, and, in the case of such mutilation,
upon surrender and cancellation of this Warrant, the Company will execute and deliver to the Warrantholder a new Warrant of like tenor. 

8. Ownership of Warrant. The Company may deem and treat the Person in whose name this Warrant is registered as the
Warrantholder and owner hereof (notwithstanding any notations of ownership or writing hereon made by anyone other than the Company) for all purposes and shall not be affected by any notice to the contrary, until presentation of this Warrant for
registration of transfer. 
 9. Amendments. Any provision of this Warrant may be amended and the observance thereof waived
only with the written consent of the Company and the Warrantholder. 

  
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 10. Definitions. As used herein, unless the context otherwise requires, the
following terms have the following respective meanings: 
 “Affiliate” means, (1) with respect to any Person,
any of (a) a director, officer or stockholder holding 5% or more of the capital stock (on a fully diluted basis) of such Person, (b) a spouse, parent, sibling or descendant of such Person (or a spouse, parent, sibling or descendant of any
director or officer of such Person) and (c) any other Person that, directly or indirectly through one or more intermediaries, controls, or is controlled by, or is under common control with, another Person or (2) in any event, any Person
meeting the definition of “Affiliate” set forth in Rule 405 under the Securities Act. The term “control” includes, without limitation, the possession, directly or indirectly, of the power to direct the management and
policies of a Person, whether through the ownership of voting securities, by contract or otherwise. 
 “Business
Day” means any day other than a Saturday, Sunday or a day on which national banks are authorized by law to close in the Commonwealth of Massachusetts. 

“Charter” means the Amended and Restated Certificate of Incorporation of the Company, as amended from time to time.

 “Common Stock” means the Company’s presently authorized Common Stock, par value $.001 per share, and any
stock into or for which such Common Stock may hereafter be converted or exchanged pursuant to the Charter of the Company as amended from time to time as provided by law and in such Charter. 

“Corporate Event” means: (i) the sale, transfer, lease, license or other conveyance or disposition of all or
substantially all of the Company’s assets; (ii) the Liquidation of the Company; or (iii) the sale, transfer or other disposition of all or substantially all of the Company’s capital stock to a Person or group of Persons that is
not an Affiliate of the Company, but does not include any one transaction or series of related transactions the sole purpose and effect of which is to change the state or type of organization of the Company (e.g., to change the Company from a
Delaware corporation to a New York corporation or from a corporation to a limited liability company). 

“Liquidation” has the meaning set forth in the Charter. 

“Person” shall be construed broadly and shall include an individual, a partnership, a corporation, a limited liability
company, an association, a joint stock company, a trust, a joint venture, an unincorporated organization, or a governmental entity (or any department, agency, or political subdivision thereof). 

“Securities Act” means the Securities Act of 1933, as amended, and the rules and regulations of the United States
Securities and Exchange Commission thereunder. 
 “Stockholders’ Agreement” means the Third Amended and
Restated Stockholders’ Agreement, dated as of the date hereof, as amended, among the Company and certain stockholders of the Company, as the same may be amended, modified or restated from time to time. 

  
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 11. Miscellaneous Provisions.  

11.1 Entire Agreement. This Warrant and the Stockholders’ Agreement constitute the entire agreement between the Company and
the Warrantholder with respect to this Warrant. 
 11.2 Binding Effect; Benefits. This Warrant shall inure to the benefit of
and shall be binding upon the Company and the Warrantholder and their respective permitted successors and assigns. Nothing in this Warrant, expressed or implied, is intended to or shall confer on any Person other than the Company and the
Warrantholder, or their respective permitted successors or assigns, any rights, remedies, obligations or liabilities under or by reason of this Warrant. 

11.3 Section and Other Headings. The section and other headings contained in this Warrant are for reference purposes only and
shall not be deemed to be a part of this Warrant or to affect the meaning or interpretation of this Warrant. 
 11.4 Notices.
All notices, demands and other communications provided for or permitted hereunder shall be made in writing and shall be by registered or certified first-class mail, return receipt requested, telecopier, courier service, overnight mail or
personal delivery: 
 If to the Company: 

Aspen Aerogels, Inc. 
 30 Forbes
Road, Building B 
 Northborough, MA 01532 

Telephone: (508) 691-1111 

Facsimile: (508) 691-1200 

Attention: Chief Executive Officer 

with a copy (which shall not constitute notice) to: 

Edwards Angell Palmer & Dodge LLP 

111 Huntington Avenue 
 Boston, MA
02199 
 Telephone: (617) 951-2207 

Facsimile: (888) 325-9513 

Attention: Christopher W. Nelson, Esq. 

If to the Warrantholder: 

to the addressees reflected on the Warrant 

register maintained by the Company 

All such notices and other communications shall be deemed to have been given and received (i) in the case of personal delivery, on the
date of such delivery, (ii) in the case of delivery by telecopy, on the date of such delivery, (iii) in the case of delivery by nationally recognized overnight courier, on the next business day following dispatch and (iv) in the case
of mailing, on the third business day following such mailing. 

  
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 11.5 Issuance Tax. The issuance of certificates for shares of Common Stock upon
exercise of this Warrant shall be made without charge to the Warrantholder hereof for any issuance tax in respect hereof, provided that the Company shall not be required to pay any tax which may be payable in respect of any transfer involved
in the issuance and delivery of any certificate in a name other than that of the Warrantholder. 
 11.6 Severability. Any term
or provision of this Warrant which is invalid or unenforceable in any jurisdiction shall, as to such jurisdiction, be ineffective to the extent of such invalidity or unenforceability without rendering invalid or unenforceable the terms and
provisions of this Warrant or affecting the validity or enforceability of any of the terms or provisions of this Warrant in any other jurisdiction. 

11.7 Governing Law. All issues concerning this Warrant shall be governed by and construed in accordance with the law of the State
of Delaware, without regard to the conflicts of law principles thereof. 
 11.8 Rights as Shareholders. The Warrantholder shall
not be entitled to vote or receive dividends or be deemed the holder of Common Stock or otherwise be entitled to any voting or other rights as a shareholder of the Company, until this Warrant shall have been exercised and the Warrant Shares
purchasable upon the exercise shall have become deliverable, as provided herein. 
 12. Disposition of Warrant or Shares of Common
Stock. With respect to any offer, sale or other transfer or disposition of this Warrant or any Warrant Shares acquired pursuant to the exercise of this Warrant prior to registration of such shares, the Warrantholder hereof and each
subsequent holder of this Warrant agrees to give written notice to the Company prior thereto, describing briefly the manner thereof, together with a written opinion of such holder’s counsel (if reasonably requested by the Company and reasonably
satisfactory to the Company) to the effect that (i) such offer, sale or other transfer or disposition may be effected without registration or qualification of this Warrant or such shares of Common Stock under the Securities Act as then in
effect, and (ii) indicating whether or not under the Securities Act this Warrant or the certificates representing such shares of Common Stock to be sold or otherwise transferred or disposed of require any restrictive legend thereon in order to
ensure compliance with the Securities Act; provided, however, that a written opinion of holder’s counsel shall not be required in connection with any sale pursuant to Rule 144. This Warrant or the certificates representing
the shares of Common Stock thus transferred (except a transfer pursuant to Rule 144) shall bear a legend as to the applicable restrictions on transferability in order to insure compliance with the Securities Act, unless in the aforesaid opinion
of counsel for the holder, such legend is not required in order to insure compliance with the Securities Act. Upon any valid transfer of this Warrant or portion thereof, Company agrees to reissue the Warrant (or Warrants in the case of a partial
transfer) and/or the Warrant Shares receivable upon the exercise hereof, and if the legend is not required, such re-issuance shall be without said legend. Nothing herein shall restrict the transfer of this Warrant (or any portion hereof) or the
certificates representing the Warrant Shares acquired pursuant to the exercise of this Warrant by the initial Warrantholder hereof or any successor holder to (i) any Affiliate of such holder, including without limitation any partnership
Affiliated with such holder, any partner of any such partnership or any successor corporation to the holder hereof as a result of a merger or 

  
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 consolidation with or a sale of all or substantially all of the stock or assets of the holder, (ii) any
Person in a public offering pursuant to an effective registration statement under the Securities Act, (iii) to any other Person to the extent that the transfer to such Person is exempt from the registration requirements of the Securities Act
and such Person agrees in writing to be bound by all of the restrictions on transfer contained herein, provided, however, that no such transfer may be made to any direct competitor of the Company, which shall mean a Person engaged in
the research, manufacture or sale of aerogels, aerogel based products or insulation products. Any transfer described above must be made in compliance with all applicable federal and state securities laws. The Company may issue stop transfer
instructions to its transfer agent in connection with the foregoing restrictions. 
 13. Warrantholder’s Representations.
The Warrantholder acknowledges that it has had access to all material information concerning the Company which it has requested. The Warrantholder also acknowledges that it has had the opportunity to, and has to its satisfaction, questioned the
officers of the Company with respect to its investment hereunder. The Warrantholder represents that it understands that the Warrant and the Common Stock are speculative investments, that it is aware of the Company’s business affairs and
financial condition and that it has acquired sufficient information about the Company to reach an informed and knowledgeable decision to acquire the Warrant. The Warrantholder is purchasing the Warrant and any Common Stock issued upon exercise
thereof for investment for its own account only and not with a view to, or for resale in connection with, any “distribution” thereof in violation of the Securities Act or applicable state securities laws. The Warrantholder further
represents that it understands that the Warrant and Common Stock have not been registered under the Securities Act or applicable state securities laws by reason of specific exemptions therefrom, which exemptions depend upon, among other things, the
bona fide nature of the Warrantholder’s investment intent as expressed herein. The Warrantholder is an “accredited investor” as defined in Regulation D promulgated under the Securities Act. 

  
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 IN WITNESS WHEREOF, the Company has caused this Warrant to be signed by its duly authorized
officer. 
  

							
	Issued By:	  	Accepted By:
		
	ASPEN AEROGELS, INC.	  	[_____________________ ]
				
	By:	  	  
	  	By:	  	  

		  	John F. Fairbanks	  	Its:	  	
		  	Chief Financial Officer	  		  	

 SIGNATURE PAGE TO ASPEN AEROGELS, INC. 

COMMON STOCK PURCHASE WARRANT 

 Exhibit A: Exercise Form  

(To be executed upon exercise of this Warrant) 
  

			
	To:	  	 Aspen Aerogels, Inc. (“Company”)

30 Forbes Road, Northborough, MA 01532

 Attention: Chief Financial Officer 

1. The undersigned hereby elects to purchase
                                    shares of Common Stock of Company
pursuant to the terms of the attached Warrants, and tenders herewith payment of the purchase price of such shares in full. 
 2. Please issue
a certificate or certificates representing said shares in the name of the undersigned or in such other name or names as are specified below: 
 [name]

 [address] 
 3. The undersigned
represents that the aforesaid shares are being acquired for the account of the undersigned for investment and not with a view to, or for resale in connection with, the distribution thereof and that the undersigned has no present intention of
distributing such shares. 
 [name] 
  

					
		  	By:	  	  

		  		  	(Signature)
	Date:                             	  	Its:EX-4.6

 Exhibit 4.6 

THIS INSTRUMENT AND THE COMMON STOCK OF
ASPEN AEROGELS, INC., A DELAWARE CORPORATION (THE “COMPANY”), ISSUABLE
UPON EXERCISE OF THIS INSTRUMENT HAVE NOT BEEN REGISTERED UNDER THE
SECURITIES ACT OF 1933 OR APPLICABLE STATE LAWS AND MAY NOT BE SOLD,
TRANSFERRED, ASSIGNED, OFFERED, PLEDGED OR OTHERWISE DISTRIBUTED FOR VALUE UNLESS
THERE IS AN EFFECTIVE REGISTRATION STATEMENT UNDER SUCH ACT AND/OR
SUCH LAWS COVERING THIS INSTRUMENT OR SUCH STOCK OR THE COMPANY, UPON
ITS REQUEST, RECEIVES AN OPINION OF COUNSEL FOR THE HOLDER OF THIS
INSTRUMENT OR SUCH STOCK STATING THAT SUCH SALE, TRANSFER, ASSIGNMENT, OFFER,
PLEDGE OR OTHER DISTRIBUTION FOR VALUE IS EXEMPT FROM THE REGISTRATION
AND PROSPECTUS DELIVERY REQUIREMENTS OF SUCH ACT AND APPLICABLE STATE LAWS. 

 THIS INSTRUMENT IS ALSO SUBJECT TO FURTHER
RESTRICTIONS ON TRANSFER AS PROVIDED IN THAT CERTAIN SUBORDINATED NOTE AND
WARRANT PURCHASE AGREEMENT, DATED AS OF DECEMBER 29, 2010, BY AND AMONG THE
COMPANY, THE PURCHASERS NAMED ON EXHIBIT A THERETO, AND PJC CAPITAL LLC, AS
COLLATERAL AGENT, AS THE SAME MAY BE AMENDED, RESTATED OR MODIFIED
FROM TIME TO TIME (THE “PURCHASE AGREEMENT”).  

THIS WARRANT AND THE SECURITIES ISSUABLE UPON
EXERCISE HEREOF ARE SUBJECT TO THE TERMS AND PROVISIONS OF THE
PURCHASE AGREEMENT. A COPY OF THE PURCHASE AGREEMENT IS AVAILABLE AT
THE EXECUTIVE OFFICES OF THE COMPANY.  
  

			
	[______] Shares of the Company	  	Warrant No. __

 WARRANT 

To Subscribe for and Purchase Common Stock of 

ASPEN AEROGELS, INC. 

THIS CERTIFIES THAT, for value received,
[                    ], a [                    ]
(“Purchaser”) or registered permitted assigns (Purchaser and/or any Person (as defined in the Purchase Agreement referred to below) or Persons to whom Purchaser has assigned this Warrant herein called “Holder”), is
entitled to subscribe for and purchase from Aspen Aerogels, Inc., a corporation organized and existing under the laws of the State of Delaware (the “Company”), at any time from and after the date hereof to and including
December 29, 2017, subject to the early termination provisions of Section 4(d) below, [                    ]
([            ]) fully paid and nonassessable shares (subject to adjustment from time to time pursuant to the provisions below) of Common Stock at the price per share as specified below and
to exercise the other rights, powers, and privileges provided for herein, all on the terms and subject to the conditions specified in this Warrant. Capitalized terms used herein and not defined shall have the meaning ascribed to them in the
Subordinated Note and Warrant Purchase Agreement, dated as of December 29, 2010, by and among the Company and the Purchasers named therein (as such agreement may be supplemented, modified, amended or restated from time to time, the
“Purchase Agreement”). 

 This Warrant is subject to the following provisions, terms and conditions: 

1. Exercise and Payment of Purchase Price. 

(a) The rights represented by this Warrant may be exercised by Holder at any time on or prior to the applicable termination or expiration
date, in whole or in part, by delivery to the Company of a completed Subscription Form in the form attached hereto ten (10) days prior to the intended date of exercise and by the surrender of this Warrant (properly endorsed if required) at the
principal office of the Company and upon payment to it of the Exercise Price as provided in paragraph 1(b) below. The Company agrees that the shares so purchased shall be and are deemed to be issued to Holder as the record owner of such
shares as of the close of business on the date that is ten (10) days after the date on which this Warrant shall have been surrendered and payment made for such shares as aforesaid. Subject to the provisions of paragraph 2, certificates
for the shares of Common Stock so purchased shall be delivered to Holder within a reasonable time, not exceeding ten (10) days, after the rights represented by this Warrant shall have been so exercised, and, unless this Warrant has expired or
all of the rights to receive shares of Common Stock under this Warrant have been exercised, a new Warrant representing the number of shares of Common Stock with respect to which this Warrant shall not then have been exercised shall also be delivered
to Holder within such time. The issuance of certificates for shares of Common Stock upon exercise of this Warrant shall be made without charge to the Holder for any issuance tax in respect thereof or other cost incurred by the Company in connection
with such exercise and the related issuance of shares of Common Stock. 
 (b) The warrant purchase price (subject to adjustment as noted
below) shall be $0.001 per share, payable by delivery of any of the following (1) a check payable to the Company in an amount equal to the product of the warrant purchase price per share multiplied by the number of shares of Common Stock being
purchased upon such exercise (the “Exercise Price”), (2) the surrender to the Company of equity securities of the Company having a Fair Market Value equal to the Exercise Price of the Common Stock being purchased upon such
exercise, (3) a written notice to the Company that Holder is exercising this Warrant (or a portion thereof) by reducing the outstanding principal balance of any debt instrument of the Company and/or any of its Subsidiaries held by Holder by an
amount equal to the Exercise Price of the Common Stock being purchased upon such exercise, (4) a written notice to the Company that Holder is exercising this Warrant (or a portion thereof) by authorizing the Company to withhold from issuance a
number of shares of Common Stock issuable upon such exercise of this Warrant which when multiplied by the Fair Market Value of such Common Stock is equal to the Exercise Price (and such withheld shares shall no longer be issuable under such Warrant)
or (5) any combination of the foregoing. 
 (c) As a condition to the exercise of this Warrant, the Holder shall execute and
deliver to the Company a Joinder Agreement whereby the Holder agrees to join as a “Stockholder” party and be bound by the terms and conditions of the Company’s Fifth Amended and Restated Stockholders’ Agreement dated as of
September 22, 2010, as amended from time to time (the “Stockholders Agreement”). The foregoing shall be inapplicable in the event that the Stockholders Agreement has been terminated in accordance with the terms thereof, or if
such Stockholders Agreement is amended to uniquely and adversely affect the rights of the Holders of the Warrants. 

  
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 2. Compliance with Transfer Restrictions. Notwithstanding the foregoing paragraph
1, the Company shall not be required to deliver any certificate for shares of Common Stock upon exercise of this Warrant except in accordance with the provisions, and subject to the limitations, of paragraph 7 hereof and the legends in
paragraph 6 and on the first page hereof. 
 3. Covenants. The Company covenants and agrees as follows: 

(a) All shares of Common Stock which may be issued upon the exercise of the rights represented by this Warrant will, upon issuance, be
duly authorized and validly issued, fully paid and nonassessable. 
 (b) During the period within which the rights represented by this
Warrant may be exercised, the Company will at all times have authorized, and reserved for the purpose of issue or transfer upon exercise of the subscription rights evidenced by this Warrant, a sufficient number of shares of its Common Stock to
provide for the exercise of the rights represented by this Warrant. 
 (c) The Company shall not close its books against the transfer of
this Warrant or of any shares of Common Stock issuable upon exercise of this Warrant in any manner which interferes with the timely exercise of this Warrant in accordance with the express terms hereof. The Company shall from time to time take all
such action as may be necessary to assure that the par value per share of the Common Stock issuable upon exercise of this Warrant is at all times equal to or less than the warrant purchase price then in effect. 

(d) The Company shall assist and cooperate with Holder in making any required governmental filings or obtaining any required governmental
approvals prior to or in connection with any exercise of this Warrant (including, without limitation, making any filings required to be made by the Company). 

(e) Notwithstanding any other provision hereof, if an exercise of any portion of this Warrant is to be made in connection with a
registered public offering, the exercise of all or any portion of this Warrant may, at the election of Holder and upon written notice to the Company of such election, be conditioned upon the consummation of the public offering, in which case such
exercise shall not be deemed to be effective unless and until the consummation of such transaction occurs, so long as such exercise occurs on or prior to the applicable termination or expiration date. 

4. Adjustments to Warrant Purchase Price and Number of Shares. The above provisions are subject to the following: 

(a) The warrant purchase price shall, from and after the date of issuance of this Warrant, be subject to adjustment from time to time as
hereinafter provided. Upon each adjustment of the warrant purchase price, the holder of this Warrant shall thereafter be entitled to purchase, at the warrant purchase price resulting from such adjustment, the number of shares of Common Stock
obtained by multiplying the warrant purchase price in effect immediately prior to such adjustment by the number of shares of Common Stock purchasable pursuant hereto immediately prior to such adjustment and dividing the product thereof by the
warrant purchase price resulting from such adjustment. 

  
 3 

 (b) If the Company declares or pays a dividend upon the Common Stock, then the following
provisions shall apply: 
 (i) If such dividend is payable in Common Stock (other than a dividend declared to effect a
subdivision of the outstanding shares of Common Stock, as described in paragraph (c) below), any Convertible Securities, or in any rights or options to purchase any Common Stock or Convertible Securities, then the Holder of this Warrant upon
exercise hereof will be entitled to receive the number of shares of Common Stock, Convertible Securities, or other rights or options to purchase any Common Stock or Convertible Securities, as applicable, to which the Holder would be entitled upon
such exercise, and in addition and without further payment therefor, such number of shares of Common Stock, Convertible Securities, or other rights or options to purchase any Common Stock or Convertible Securities, as applicable, such that upon
exercise hereof, the Holder would receive such number of shares of Common Stock, Convertible Securities, or other rights or options to purchase any Common Stock or Convertible Securities, as applicable, as a result of each dividend described above.

 (ii) If such dividend is payable otherwise than in cash out of earnings or earned surplus (determined in accordance with
GAAP), except for a stock dividend payable in shares of Common Stock as provided above (a “Liquidating Dividend”), then the Company shall pay to the Holder of this Warrant at the time of payment thereof the Liquidating Dividend
which would have been paid to such Holder on the Common Stock issuable upon exercise of this Warrant had the Warrants been fully exercised immediately prior to the date on which a record is taken for such Liquidating Dividend, or, if no record is
taken, the date as of which the record holders of Common Stock entitled to such dividends are to be determined. 
 (ii) If
such dividend is payable in cash out of earnings or earned surplus (determined in accordance with GAAP) (a “Dividend”), then (A) such Dividend shall be allocated proportionately to the holders of outstanding Common Stock and
holders of all Warrants as though all Warrants (and, to the extent required by the terms thereof, any other warrants, options, Convertible Securities or other rights to acquire shares of Common Stock) had been fully exercised immediately prior to
the date on which a record was taken for such Dividend, or, if no record was taken, the date as of which the record holders of Common Stock entitled to such dividends were determined, (B) the amount allocable to the Warrants shall be deposited
by the Company in a separate interest-bearing account concurrently with the payment of such Dividend to the holders of Common Stock and (C) promptly after the exercise of this Warrant, the amount allocable to the Common Stock obtained by the
Holder upon such exercise, plus all accrued interest thereon, shall be paid to the Holder. 
 (c) In case the Company shall at any time
subdivide its outstanding shares of Common Stock into a greater number of shares, the warrant purchase price in effect immediately prior to such subdivision shall be proportionately reduced, and conversely, in case the outstanding shares of Common
Stock of the Company shall be combined into a smaller number of shares, the warrant purchase price in effect immediately prior to such combination shall be proportionately increased. 

  
 4 

 (d) If any capital reorganization or reclassification of the capital stock of the Company,
or consolidation or merger of the Company with another corporation or other entity, or the sale of all or substantially all of its assets to another corporation or other entity shall be effected in such a way that holders of Common Stock shall be
entitled to receive stock, securities or assets with respect to or in exchange for Common Stock, then, as a condition of such reorganization, reclassification, consolidation, merger or sale, lawful and adequate provision shall be made whereby the
Holder shall thereafter have the right to purchase and receive, upon the basis and upon the terms and conditions specified in this Warrant (and in lieu of the shares of Common Stock purchasable upon the exercise of this Warrant), an amount of shares
of stock, securities or assets as may be issued or payable with respect to or in exchange for such Common Stock that are equal to the number of shares of such stock immediately purchasable and receivable upon exercise of this Warrant had such
reorganization, reclassification, consolidation, merger or sale not taken place. In any such case, appropriate provision shall be made with respect to the rights and interests of the Holder of this Warrant to the end that the provisions hereof
(including without limitation provisions for adjustments of the warrant purchase price and of the number of shares of Common Stock purchasable upon the exercise of this Warrant) shall thereafter be applicable, as nearly as may be possible, in
relation to any shares of stock, securities or assets thereafter deliverable upon the exercise hereof. The Company shall not effect any such consolidation, merger or sale, unless prior to the consummation thereof the successor corporation or other
entity (if other than the Company) resulting from such consolidation or merger or the corporation or other entity purchasing such assets shall assume, by written instrument executed and mailed to the Holder of this Warrant at the last address of
such Holder appearing on the books of the Company, the obligation to deliver to such Holder such shares of stock, securities or assets as, in accordance with the foregoing provisions, such Holder may be entitled to purchase. Notwithstanding anything
to the contrary herein, if any consolidation or merger of the Company with another corporation or other entity, or the sale of all or substantially all of its assets to another corporation or other entity, shall be effected in such a way that all
holders of Common Stock shall be entitled to receive shares of stock, securities, cash or assets with respect to or in exchange for Common Stock, then at its election the Company may provide the Holder of this Warrant with written notice of such
proposed transaction, in reasonable detail, no less than ten (10) days prior to the consummation thereof, and, upon the Holder receiving an amount of shares of stock, securities, cash or assets that may be payable with respect to or in exchange
for such Common Stock that is equal to the number of shares of such stock immediately purchasable and receivable upon the exercise of this Warrant had such consolidation, merger or sale not taken place less an amount of such consideration payable in
the proposed transaction with a Fair Market Value equal to the aggregate Exercise Price, this Warrant shall terminate. 
 (e) Upon any
adjustment of the warrant purchase price, then and in each such case the Company shall give written notice thereof, by first-class mail, postage prepaid, addressed to the Holder of this Warrant at the address of such Holder as shown on the books of
the Company, which notice shall state the warrant purchase price resulting from such adjustment and the increase or decrease, if any, in the number of shares of Common Stock purchasable at such price upon the exercise of this Warrant, setting forth
in reasonable detail the method of calculation and the facts upon which such calculation is based. 

  
 5 

 (f) In case any time: 

(i) the Company shall declare any cash dividend on its Common Stock; 

(ii) the Company shall pay any dividend payable in stock upon its Common Stock or make any distribution (other than regular
cash dividends) to the holders of its Common Stock; 
 (iii) the Company shall offer for subscription pro rata to the holders
of its Common Stock any additional shares of stock of any class or other rights; 
 (iv) there shall be any capital
reorganization, or reclassification of the capital stock of the Company, or consolidation or merger of the Company with, or sale of all or substantially all of its assets to, another corporation or other entity; or 

(v) there shall be a voluntary or involuntary dissolution, liquidation or winding up of the Company; 

then, in any one or more of said cases, the Company shall give written notice, by first-class mail, postage prepaid, addressed to the Holder of this Warrant at
the address of such Holder as shown on the books of the Company, of the date on which (A) the books of the Company shall close or a record shall be taken for such dividend, distribution or subscription rights, or (B) such reorganization,
reclassification, consolidation, merger, sale, dissolution, liquidation or winding up shall take place, as the case may be. Such notice shall also specify the date as of which the holders of Common Stock of record shall participate in such dividend,
distribution or subscription rights, or shall be entitled to exchange their Common Stock for securities or other property deliverable upon such reorganization, reclassification, consolidation, merger, sale, dissolution, liquidation or winding up, as
the case may be. Such written notice shall be given at least ten (10) days prior to the action in question and not less than ten (10) days prior to the record date or the date on which the Company’s transfer books are closed in
respect thereto. 
 (g) If any event occurs as to which in the opinion of the Board of Directors of the Company the other provisions of
this paragraph 4 are not strictly applicable or if strictly applicable would not fairly protect the purchase rights of the Holder of this Warrant or of Common Stock issuable upon exercise of this Warrant in accordance with the essential
intent and principles of such provisions, then the Board of Directors shall make an adjustment in the application of such provisions, in accordance with such essential intent and principles, so as to protect such purchase rights as aforesaid. 

(h) No fractional shares of Common Stock shall be issued upon the exercise of this Warrant, but, instead of any fraction of a share which
would otherwise be issuable, the Company shall pay a cash adjustment (which may be effected as a reduction of the amount to be paid by the Holder hereof upon such exercise) in respect of such fraction in an amount equal to the same fraction of the
Fair Market Value per share of Common Stock as of the close of business on the date of the notice of exercise required by paragraph 1 above. 

  
 6 

 5. Voting Rights. This Warrant shall not entitle the Holder hereof to any voting
rights or, except as expressly provided herein, other rights as a stockholder of the Company. 
 6. Limitations on Transfer. 

(a) The Holder, by acceptance hereof, agrees that this Warrant shall not be transferable except to an Affiliate of the Holder or with the
Company’s prior written consent (not to be unreasonably withheld.) In the event of a permitted transfer, the Holder agrees to give written notice to the Company before transferring this Warrant or any Warrant Stock and to comply with the legend
at the top hereof (the “Legend”). Upon receipt by the Company of such notice and satisfaction of the requirements of the Legend, such Holder shall be entitled to transfer this Warrant, or to exercise this Warrant in accordance with
its terms and dispose of the shares of Common Stock received upon such exercise or to dispose of shares of Common Stock received upon the previous exercise of the Warrant, all in accordance with the terms of hereof. 

(b) All certificates representing shares of Common Stock issued upon exercise of this Warrant shall be endorsed with the following legend:

 “THE SECURITIES REPRESENTED BY THIS
CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933 OR
APPLICABLE STATE LAWS AND MAY NOT BE SOLD, TRANSFERRED, ASSIGNED, OFFERED,
PLEDGED OR OTHERWISE DISTRIBUTED FOR VALUE UNLESS THERE IS AN EFFECTIVE
REGISTRATION STATEMENT UNDER SUCH ACT AND/OR SUCH LAWS COVERING SUCH
SECURITIES OR THE COMPANY, UPON ITS REQUEST, RECEIVES AN OPINION OF
COUNSEL FOR THE HOLDER OF THIS CERTIFICATE STATING THAT SUCH SALE,
TRANSFER, ASSIGNMENT, OFFER, PLEDGE OR OTHER DISTRIBUTION FOR VALUE IS EXEMPT
FROM THE REGISTRATION AND PROSPECTUS DELIVERY REQUIREMENTS OF SUCH ACT AND
APPLICABLE STATE LAWS.”  
 (c) The restrictions imposed by the Legend and by the
legend referred to in paragraph 6(b) shall cease and terminate as provided in Section 9.19(F) of the Purchase Agreement. 

7. Warrant Transferable. Subject to the provisions of Section 9.19 of the Purchase Agreement and paragraph 6
hereof, this Warrant and all rights hereunder are transferable, in whole or in part, at the principal office of the Company by the Holder hereof in person or by duly authorized attorney, upon surrender of this Warrant properly endorsed. Each Holder
of this Warrant, by holding the same, consents and agrees that the registered holder of this Warrant may be treated by the Company and all other Persons dealing with this Warrant as the absolute owner thereof for any purpose and as the Person
entitled to exercise the rights represented by this Warrant, or to the transfer thereof on the books of the Company, any notice to the contrary notwithstanding. 

8. Registration Rights Agreement. Contemporaneously with the issuance to Purchaser of this Warrant, the Purchaser and the Company
shall execute and deliver a joinder to, and be bound by and entitled to the benefits of, the Registration Rights Agreement. 

  
 7 

 9. Exchange of Warrant. This Warrant is exchangeable, upon the surrender thereof at
the principal office of the Company, for new Warrants of like tenor representing in the aggregate the right to subscribe for and purchase the number of shares of Common Stock which may be subscribed for and purchased hereunder, each of such new
Warrants to represent the right to subscribe for and purchase such number of shares of Common Stock as shall be designated by the Holder hereof at the time of such surrender. 

10. Replacement of Warrant. Upon receipt of evidence reasonably satisfactory to the Company (an affidavit of Holder shall be
satisfactory) of the ownership and the loss, theft, destruction or mutilation of this Warrant, and in the case of any such loss, theft or destruction, upon receipt of indemnity reasonably satisfactory to the Company (provided that if Holder is a
Purchaser or qualifies as an “accredited investor” under the Securities Act, its own agreement regarding indemnity shall be satisfactory), or, in the case of any such mutilation upon surrender of this Warrant, the Company shall (at its
expense) execute and deliver, in lieu thereof, a new Warrant of like kind representing the same rights represented by such lost, stolen, destroyed or mutilated Warrant and dated the date of such lost, stolen, destroyed or mutilated Warrant. 

11. Certain Definitions. The following terms have the respective meanings set forth below: 

“Average Market Value” means the average of the Closing Price for the security in question for the thirty (30) trading
days immediately preceding the date of determination. 
 “Closing Price” means 

(a) If the primary market for the security in question is a securities exchange or other market or quotation system in which
last sale transactions are reported on a contemporaneous basis, then the last reported sales price, regular way, of such security for such day, or, if there has not been a sale on such trading day, then the highest closing or last bid quotation
therefor on such trading day (excluding, in any case, any price that is not the result of bona fide arm’s length trading); or 

(b) If the primary market for such security is not a securities exchange or other market or quotation system in which last sale
transactions are contemporaneously reported, then the highest closing or last bona fide bid or asked quotation by disinterested Persons in the over-the-counter market on such trading day as reported by such generally accepted source of publicly
reported bid quotations as the Holder designates. 
 “Common Stock” shall mean and include the Company’s Common Stock,
par value $.001 per share, and shall also include, in the case of any reclassification of the outstanding shares thereof, the stock, securities or assets provided for in paragraph 4(d) above. 

“Convertible Securities” means obligations or any shares of stock of the Company which are convertible into or exchangeable
for Common Stock. 
 “Exchange Act” means the Securities Exchange Act of 1934, as the same may be amended from time to
time. 
 “Exercise Price” shall have the meaning ascribed thereto in paragraph 1(b). 

  
 8 

 “Fair Market Value” means: 

(a) As to securities regularly traded in the organized securities markets, the Average Market Value; and 

(b) As to all securities not regularly traded in the securities markets and all other property, the fair market value of such securities or
property as determined in good faith by the Board of Directors of the Company at the time the rights represented by this Warrant have been exercised in accordance herewith or at the time such Board authorizes the transaction requiring a
determination of Fair Market Value under this Warrant, as the case may be. 
 “Securities Act” means the Securities Act of
1933, as the same may be amended from time to time. 
 12. Choice of Law. All questions concerning this Warrant will be governed
by and construed in accordance with the internal laws of the State of New York, without reference to principles of conflicts of law other than Sections 5-1401 and 5-1402 of the New York General Obligations Law. 

13. Headings. Section and subsection headings are included herein for convenience of reference only and shall not constitute a part
of this Warrant for any other purposes or be given substantive effect. 
 14. Severability. The invalidity, illegality, or
unenforceability in any jurisdiction of any provision under this Warrant shall not affect or impair the remaining provisions of this Warrant or render any such provision invalid, illegal or unenforceable in any other jurisdiction. 

[Remainder of Page Intentionally Left Blank] 

  
 9 

 IN WITNESS WHEREOF, the Company has caused this Warrant to be signed by its duly authorized
officer and this Warrant to be dated as of             . 
  

	
	ASPEN AEROGELS, INC.
	
	By:                                     
                                         
                         
	Name:                                     
                                         
                   
	Title:                                     
                                         
                     

 [Signature Page to Warrant for
[            ] Shares] 

 FORM OF ASSIGNMENT 

(To Be Signed Only Upon Assignment) 

FOR VALUE RECEIVED, the undersigned hereby sells, assigns and transfers unto
            this Warrant, and appoints             to transfer this Warrant on the books of Aspen Aerogels, Inc. with the full
power of substitution in the premises. 
 Dated: 
 In the
presence of: 
  

	
	  
  

(Signature must conform in all respects to the name of the holder as specified on the face of this Warrant without alteration, enlargement
or any change whatsoever, and the signature must be guaranteed in the usual manner)

 SUBSCRIPTION FORM 

To be Executed by the Holder of this Warrant if such Holder 

Desires to Exercise this Warrant in Whole or in Part: 

To: Aspen Aerogels, Inc. 
 The undersigned
                                         
    
 Please insert Social Security or other 

identifying number of Subscriber: 
  

 
 hereby irrevocably elects to
exercise the right of purchase represented by this Warrant for, and to purchase thereunder,             shares of the Common Stock provided for therein and tenders payment herewith to the
order of Aspen Aerogels, Inc. in the amount of $            , in one or more of the forms permitted by this Warrant. 

The undersigned requests that certificates for such shares of Common Stock be issued as follows: 

 

	
	
Name:                        
                                         
                                         
                                         
                                         
                                         
               

	
	
Address:                       
                                         
                                         
                                         
                                         
                                         
            

	
	 Deliver
to:                                        
                                         
                                         
                                         
                                         
                                

	
	
Address:                       
                                         
                                         
                                         
                                         
                                         
            

 and, if such number of shares of Common Stock shall not be all the shares of Common Stock purchasable hereunder, that a new
Warrant for the balance remaining of the shares of Common Stock purchasable under this Warrant be registered in the name of, and delivered to, the undersigned at the address stated above. 

Dated: 
  

			
	Signature	  	  

		  	  
 Note: The signature on this Subscription Form must
correspond with the name as written upon the face of this Warrant in every particular, without alteration or enlargement or any change whatever.

  
 1

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