Document:

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                                  EXHIBIT 10.20

                                ESCROW AGREEMENT

         ESCROW AGREEMENT ("Escrow Agreement"), made March __, 2001, by and
among WESTVACO BRAND SECURITY, INC., a Delaware corporation (the "Licensee"),
NOCOPI TECHNOLOGIES, INC., a Maryland corporation (the "Licensor") and the law
firm of HANGLEY ARONCHICK SEGAL & PUDLIN, a professional corporation ("HAS&P" or
the "Escrow Agent").

                                   Background

         Licensor and Licensee have entered into a License Agreement dated as of
September 1, 2000 and an Amendment thereto dated December 19, 2000 (such
agreement, as so amended and as it may hereafter further be amended, is
hereinafter referred to as the "License Agreement") pursuant to which, among
other things, Licensor granted to Licensee rights to market, promote, sell and
manufacture certain products which incorporate "Nocopi Technology" (as such term
is defined in the License Agreement.) Certain elements of the Nocopi Technology
are the subject of one or more United States patents (such patents, together
with all related patent applications and submittals and all extensions and
modifications thereof, are hereinafter referred to as the "Patents"), and
information concerning such elements is on file with the United States Patent
and Trademark Office and is publicly available. Other information potentially
necessary for the commercial exploitation of the Nocopi Technology as
contemplated by the License Agreement is proprietary information of Licensor
that is not publicly available.

         Contemporaneously with the execution of this Agreement, Licensor has
executed and delivered to Licensee a certain Collateral Assignment of Patent
Rights to secure its obligations under the License Agreement. To provide further
assurances to Licensee that it will be able to enjoy the benefits accruing to it
under the License Agreement, Licensee and Licensor have agreed that Licensor
will deposit certain materials relevant to the Nocopi Technology with HAS&P, as
escrow agent, to be held and delivered in accordance with the terms and
conditions of this Agreement, and HAS&P has agreed to serve in such capacity,
all under and subject to the terms and conditions of this Agreement.

         NOW, THEREFORE, for and in consideration of the mutual covenants
contained herein, the parties hereto, intending to be legally bound, hereby
covenant and agree as follows:

         1. Appointment of Escrow Agent.

         HAS&P is hereby appointed to act as escrow agent to hold the materials
to be deposited with it as set forth in Section 2 (the "Escrow Materials") and
to make distribution of the Escrow Materials only in accordance with the terms
hereof, and HAS&P hereby accepts such appointment and agrees to act in the
capacity of escrow agent in accordance with the terms hereof.

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         2. Delivery of Escrow Materials; Acknowledgment of Receipt.

         Within five Business Days (as hereinafter defined) after the execution
hereof, Licensor shall deliver to HAS&P, in a sealed envelope, one copy of all
unpublished and proprietary technical documentation, including relevant
formulae, commentary and explanatory matter for the production of Nocopi's inks,
reasonably necessary, together with information which is publicly available from
the United States Patent and Trademark Office with respect to the Patents, to
permit the commercial exploitation of the Nocopi Technology by Licensee as
contemplated by the License Agreement without further assistance or cooperation
by Licensor. Escrow Agent shall accept such sealed envelope and shall hold it
unopened, without examining, or having any responsibility for reviewing,
examining or verifying in any respect, the contents of such envelope. Promptly
following its receipt of such envelope from Licensor, Escrow Agent shall
acknowledge its receipt thereof in writing to Licensor and Licensee.

         3. Disposition of Escrow Materials.

         The Escrow Agent shall not dispose of the Escrow Materials or any
portion thereof except:

                  (a) in accordance with a written instruction, in the form of
Exhibit 3, executed jointly or in counterparts by both (i) Licensee and (ii) the
Licensor (in which case the required disposition of the Escrow Materials or
portion thereof shall be made within five (5) Business Days after the Escrow
Agent's receipt of, and in accordance with, such instruction); or

                  (b) to the Licensee, in accordance with Licensee's written
demand for delivery, with a copy to the other parties hereto, accompanied by a
copy of a final order or judgment of a court of competent jurisdiction or
decision of an arbitration panel determining the rights of Licensee and the
Licensor with respect to the Escrow Materials and supporting such demand for
delivery, accompanied by an opinion of counsel to the demanding party, addressed
to the Escrow Agent and stating that (i) such order or judgment has been finally
affirmed on appeal by the highest court before which such appeal may be sought
or has become final by lapse of time or is otherwise not subject to appeal or
(ii) such decision of the arbitration panel is binding and is not subject to
appeal (in which case the required disposition of the Escrow Materials or
portion thereof shall be made within five (5) Business Days after the Escrow
Agent's receipt of, and in accordance with, such demand, unless another time for
such disposition is provided in the order, judgment or decision); or

                  (c) to the Licensor, but only following written confirmation
by the Licensee that the License Agreement is terminated and that it has no
further interest as a licensee thereunder (which written confirmation Licensee
agrees to furnish promptly upon the termination or expiration of the License
Agreement); or

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                  (d) to a successor escrow agent or a court of competent
jurisdiction as contemplated by Section 4.8 of this Agreement; or

                  (e) in the event that the Escrow Agent believes that a dispute
exists or is likely to exist between the Licensor and the Licensee with respect
to the License Agreement or the Escrow Materials, to any court of competent
jurisdiction. "Business Day" shall mean a day other than a Saturday, Sunday or
day on which a state bank is authorized or permitted to close in the
Commonwealth of Pennsylvania.

         4. Certain Provisions Pertaining to the Escrow Agent.

                  Licensee and the Licensor hereby recognize and acknowledge
that the Escrow Agent did not seek its role hereunder and is serving hereunder
at the request of, and as an accommodation to, Licensee. The Escrow Agent is not
being paid specially for services hereunder. Accordingly, it is understood and
agreed as follows:

                  4.1 Administrative Duties. The Escrow Agent shall hold the
Escrow Materials during the period or periods specified in this Escrow Agreement
and shall dispose of the Escrow Materials in accordance with the terms hereof
and not as the property of the Escrow Agent. The duties and responsibilities of
the Escrow Agent shall be entirely administrative and not discretionary, and
shall arise solely under and in accordance with this Escrow Agreement.

                  4.2 Limitation of Escrow Agent's Liability; Exculpation. Each
of the Licensee and the Licensor agrees, for the Escrow Agent's benefit, that
the Escrow Agent shall not be liable to Licensor or Licensee for monetary
damages by reason of this Escrow Agreement, or by reason of the performance or
non-performance by Escrow Agent of its duties hereunder, except for the actual
damages of a party directly caused by the willful misconduct or bad faith of the
Escrow Agent in connection with this Escrow Agreement. In no event shall the
Escrow Agent be liable for any indirect, consequential, incidental, or special
damages, or for punitive or exemplary damages.

         In addition, and not in limitation of the preceding paragraph, Escrow
Agent shall not be liable for any reasonable action taken by it in good faith
and believed by it to be authorized or within the rights or powers conferred
upon it by this Escrow Agreement, and may consult with counsel of its own choice
and shall have full and complete authorization and protection for any action
taken or suffered by it hereunder in good faith or in accordance with or in
reliance upon the opinion of such counsel. In addition, the Escrow Agent shall
have no liability if it distributes the Escrow Materials in accordance with
Section 3 or an order of a court of competent jurisdiction or if it delivers
such Escrow Materials to such a court for disposition by such court.

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                  4.3 Genuineness. Escrow Agent may rely and shall be protected
in acting or refraining from acting upon any written notice, instruction or
request furnished to it hereunder and believed by it to be genuine and to have
been signed or printed by the proper party or parties.

                  4.4 Indemnification. Licensor and Licensee hereby, jointly and
severally, indemnify and hold harmless the Escrow Agent and its shareholders,
directors, officers and employees, and their respective successors, heirs and
assigns, from and against all claims, demands, costs, liabilities and expenses,
including, without limitation, attorneys' fees and costs which may be asserted
against any of them or to which any of them may be exposed or may incur or
suffer, directly or indirectly, by reason of the execution or performance or
non-performance of this Escrow Agreement by Escrow Agent, unless (and only to
the extent that) such claims, demands, costs, liabilities or expenses are based
upon the willful misconduct or bad faith of the Escrow Agent in performing its
duties pursuant to this Escrow Agreement. This Section 4.4 shall survive and
continue in effect notwithstanding any termination of this Escrow Agreement or
the resignation of the Escrow Agent. The indemnification provided in this
Section 4.4 is only for the benefit of the Escrow Agent and its shareholders,
directors, officers and employees and their respective successors and assigns,
and not for the benefit of any other party to this Agreement..

                  4.5 Reimbursement. Escrow Agent hereby agrees that it is
serving hereunder as an accommodation to the Licensor and the Licensor and shall
impose no charge for its services hereunder, provided such services are limited
to the duties expressly set forth in this Escrow Agreement.

                  4.6 Waiver of Conflicts. Neither the Escrow Agent's acceptance
of its duties as Escrow Agent hereunder nor its performance or non-performance
thereof shall affect the right of the Escrow Agent to represent, or have
business or other relationships with the Licensor, and Licensee and the Licensor
each hereby waives all conflicts of interest or differing interests, if any,
arising from or in connection with the acceptance and performance of this Escrow
Agreement by the Escrow Agent. In addition, Licensee and the Licensor hereby
agree that they will not raise or otherwise assert a claim against the Escrow
Agent based upon a conflict of interest as a result of its service as Escrow
Agent hereunder and representation of Licensor and agree that delivery by the
Escrow Agent of the Escrow Materials into a court of competent jurisdiction
shall satisfy any restrictions arising from a real or perceived conflict of
interest that may arise in connection herewith.

                  4.7 No Other Duties. This Escrow Agreement expressly sets
forth all the duties of the Escrow Agent with respect to any and all matters
pertinent hereto. No implied duties or obligations shall be read into this
Escrow Agreement against the Escrow Agent. Escrow Agent shall not be bound by
the provisions of any agreement among the other parties hereto except this
Escrow Agreement.

                  4.8 Resignation. Escrow Agent may resign and be discharged
from its duties or obligations under this Escrow Agreement by giving not less
than thirty (30) days' prior written notice to the Licensee and the Licensor of
such resignation, provided that no such resignation shall be effective until a
successor Escrow Agent, designated jointly by Licensee and the Licensor, has
agreed to serve as Escrow Agent in accordance with the terms of this Escrow

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Agreement. Notwithstanding the foregoing, if no successor is appointed within
thirty (30) days after such resignation notice is deemed given hereunder, the
Escrow Agent may deliver the Escrow Materials into a court of competent
jurisdiction and, thereupon, shall be released from any and all obligations and
liabilities arising under or in connection with this Escrow Agreement or its
duties as an escrow agent hereunder.

         5. Termination.

         The duties of the Escrow Agent shall be terminated (a) upon delivery of
the Escrow Materials by the Escrow Agent in accordance with this Escrow
Agreement; (b) by written mutual consent signed by all parties, or (c) by
delivery of the Escrow Materials into a court of competent jurisdiction pursuant
to or in accordance with this Agreement.

         6. Miscellaneous.

                  6.1 Entire Agreement; Amendment. This Escrow Agreement
embodies the entire agreement and understanding of the parties hereto with
respect to the subject matter hereof, and there are no prior or contemporaneous
agreements, understandings, inducements, conditions, representations,
warranties, covenants or other commitments of any kind, express or implied,
between the parties hereto, other than those set forth in this Escrow Agreement
and in the other written agreements referred to in this Escrow Agreement. This
Escrow Agreement may be amended only by a written instrument, signed by Licensee
and the Licensor.

                  6.2 Exhibits and Sections. All references herein to an
"Exhibit" or "Section" refer to an exhibit to or section of this Escrow
Agreement. The captions of the Sections are not to be considered part of this
Escrow Agreement, are included solely for convenience, are not intended to be
full or accurate descriptions of the content thereof and shall not affect the
construction thereof. The Exhibits are an integral part of this Escrow
Agreement.

                  6.3 Severability. The provisions of this Escrow Agreement are
severable, and in the event that any provision hereof should, for any reason, be
held invalid or unenforceable in any respect, it shall not invalidate, render
unenforceable or otherwise affect any other provision hereof, and such invalid
or unenforceable provision shall be construed by limiting it so as to be valid
and enforceable to the maximum extent compatible with, and possible under,
applicable law.

                  6.4 Parties in Interest. All of the terms and provisions of
this Escrow Agreement shall be binding upon and shall inure to the benefit of
the parties hereto and their respective transferees, delegatees, heirs,
devisees, successors and assigns. Except as otherwise expressly provided herein,
neither Licensee's nor an Licensor's rights or obligations under this Escrow
Agreement shall be assignable without the express written consent of the other
party. There are no intended third party beneficiaries of this Escrow Agreement

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and this Escrow Agreement is not intended to, and shall not, create any right,
cause of action in or on behalf of any person or entity other than the parties
hereto and their respective successors or assigns.

                  6.5 Notices. All notices required to be given hereunder shall
be given in writing to the appropriate party or parties at the following
addresses:

                           (a)      If to Licensee:

                                    Westvaco Brand Security, Inc.
                                    One High Ridge Park
                                    Stamford, CT 06905
                                    Attention: Chief Executive Officer

                           (b)      If to Escrow Agent:

                                    David B. Pudlin, Esq.
                                    Hangley Aronchick Segal & Pudlin,
                                      a professional corporation
                                    One Logan Square -- 27th Floor
                                    Philadelphia, PA 19103

                           (c)      If to Licensor:

                                    Nocopi Technologies, Inc.
                                    537 Apple Street
                                    West Conshohocken, PA 19428
                                    Attention: Chief Executive Officer

         Each party may change its address for purposes of receiving notices
hereunder by giving a notice of such change to the other party at least ten days
in advance thereof. All notices shall be delivered either in person or by
registered mail, return receipt requested, and shall be deemed to have been
delivered, if in person upon delivery thereof, or if by registered mail on the
date shown on the return receipt.

                  7.6 Governing Law. This Escrow Agreement and the rights and
obligations of the parties hereunder shall be construed in accordance with and
shall be governed by the laws of the Commonwealth of Pennsylvania, without
regard to principles of conflicts of law.

                  7.7 Construction. All references herein to the masculine
gender shall also include the feminine and neuter, and vice versa, and all
references herein to the singular form shall also include the plural, and vice
versa, all as the context may require.

                  7.8 Timing. Time is of the essence of all provisions of this
Escrow Agreement.

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                  7.9 Counterparts. This Escrow Agreement may be executed in any
number of counterparts, each of which shall be deemed an original, but all of
which together shall constitute but one and the same instrument.

                  7.10 Venue for Suit. Licensor and Licensee agree that the
Escrow Agent shall not be made a party to any suit or action arising out of or
relating to this Agreement except for a suit or action commenced in a court of
general jurisdiction sitting in Philadelphia, Pennsylvania, which shall be the
exclusive venue of any such action. If the Escrow Agent is made a party to any
suit or action in violation of this Section 7.10, it shall be dismissed from
such action upon its motion or request, and the party responsible for making the
Escrow Agent a party to such suit or action shall pay all costs and expenses,
including attorneys' fees, incurred by the Escrow Agent in obtaining such
dismissal.

         IN WITNESS WHEREOF, the parties hereto have duly executed this Escrow
Agreement as of the date first above written.

                                            WESTVACO BRAND SECURITY, INC.

                                            By:_____________________________
                                               Name:
                                               Title:

                                            NOCOPI TECHNOLOGIES, INC.

                                            By:_____________________________
                                               Name: Michael A. Feinstein
                                               Title: Chairman

                                            HANGLEY ARONCHICK SEGAL & PUDLIN,
                                               a professional corporation,
                                               as Escrow Agent

                                            By: ___________________________
                                                Name: David B. Pudlin, Esquire
                                                Title: President

                                        7<PAGE>

                                  EXHIBIT 10bb

                     AMENDMENT NO. 1 TO AMENDED AND RESTATED
                     REVOLVING CREDIT AND SECURITY AGREEMENT

         AMENDMENT NO. 1 dated as of February 16, 2001, by and among MARLTON
TECHNOLOGIES, INC., a New Jersey corporation ("Marlton"), and certain
subsidiaries executing this Amendment as Borrowers (together with Marlton,
collectively, the "Borrowers") and FIRST UNION NATIONAL BANK, a national banking
association, as Bank (the "Bank") and as Agent (the "Agent").

         WHEREAS, the Borrowers, the Agent and the Banks entered into a certain
 Amended and Restated Revolving Credit and Security Agreement dated as of
 January 21, 2000 (as amended on the date hereof and hereafter, the "Credit
 Agreement"); capitalized terms not otherwise defined herein having the meanings
 set forth in the Credit Agreement; and

         WHEREAS, the parties wish to amend certain provisions of the Credit
Agreement;

         NOW THEREFORE, in consideration of the mutual agreements herein
contained, the parties hereto, intending to be legally bound, hereby agree as
follows, effective on the date first above written.

          1. Excluded Reserves. For purposes of determining compliance with the
 covenants set forth hi Section 6.25, 6.26 and 6.27 of the Agreement and for
 purposes of the definition of "Applicable Margin," for the fiscal quarters
 ending on September 30, 2000, December 31, 2000, March 31, 2001 and June 30,
 2001 (but not thereafter), EBITDA shall be calculated without taking into
 account an aggregate of Two Million Dollars ($2,000,000) (but no more) recorded
 as accounts receivable and inventory reserves (the "Excluded Reserves") as of
 the fiscal quarter ended September 30, 2000; provided that, to the extent there
 is a decrease in or reversal of the Excluded Reserves, the resulting income
 shall not be taken into account for the above-referenced purposes.

          2.  "Applicable Margin." The definition of "Applicable Margin" shall
be amended to read in full as follows:

              "Applicable Margin" means, in accordance with the table and text
below:

                                                           Applicable Margin:

                                                         LIBOR Loans      Base
If the ratio of Senior Funded Debt to                    and Letter of    Rate
EBITDA is:                                               Credit Fees:     Loans:
-------------------------------------                    -----------------------

Higher than 3.00:1 (it being                                2.75%         0.50%
acknowledged that the maximum
permitted ratio of Senior Funded Debt
to EBITDA may never exceed the
amount permitted under Section 6.25)

3.00:1 or lower, but higher than 2.50:1                     2.00%         0.00%

2.50:1 or lower, but higher than 2.00:1                     1.75%        -0.25%

Less than or equal to 2.00:1                                1.25%        -0.25%

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                  The calculation of the Applicable Margin pursuant to the above
                  tables shall be made quarterly, based upon the Interim
                  Financial Statements or Financial Statements, as applicable,
                  of MTI and its Subsidiaries as at the last day of each such
                  fiscal quarter and for the fiscal period then ended. In the
                  event that the Applicable Margin changes, such change shall
                  become effective for Eurodollar Loans then existing or
                  thereafter made, as of the first day of the fiscal quarter
                  immediately following the date on which such financial
                  statements are delivered to the Agent. In the event that such
                  financial statements are not delivered to the Agent on or
                  before the date required under this Agreement, the Applicable
                  Margin shall be calculated as if the Funded Debt to EBITDA is
                  greater than 3.00:1, effective upon the last day of the fiscal
                  quarter to which such financial statements relate, and until
                  such financial statements are delivered showing that the
                  Borrowers are entitled to a lower rate hereunder.

         3. Senior Funded Debt to EBITDA Ratio. Section 6.25 shall be amended to
 read in full as follows:

                  The Borrowers will not permit the ratio of Senior Funded Debt,
                  determined as of the last day (a "Measurement Date") of each
                  period of four consecutive fiscal quarters of MTI, to EBITDA
                  for such period to be greater than (a) 3.50:1.00 for each such
                  period ending on or prior to September 30, 2001, and (b)
                  thereafter, 3.25:1.0.

         4. Representations and Covenants. The Borrowers hereby represent,
 warrant and certify that, assuming the effectiveness of Paragraph 1 of this
 Amendment: (a) all representations and warranties contained in the Credit
 Agreement, including without limitation the schedules thereto (updated as
 attached hereto), are true, correct and complete on and as of the date hereof,
 (b) all covenants and agreements made in the Credit Agreement have been
 complied with and fulfilled, (c) no Default or Event of Default is in existence
 on the date hereof, and (d) this Amendment has been duly authorized, executed
 and delivered by each Borrower and is the legal, valid and binding obligation
 of each of the Borrowers, enforceable in accordance with its terms.

         5. Ratification. Other than as specifically set forth herein, the
Borrowers hereby ratify and confirm the Credit Agreement and all instruments and
agreements relating thereto, and confirm that (a) all of the foregoing remain in
full force and effect, (b) each of the foregoing is enforceable against the
Borrowers in accordance with its terms, and (c) Borrowers have no defenses to
its obligations or claims relative to the Credit Agreement.

         6. Miscellaneous. Article IX of the Credit Agreement is incorporated
 herein by reference and shall apply to this Amendment. Execution of this
 Amendment shall not constitute an agreement by the Agent or any Bank to execute
 any other amendment or modification of the Credit Agreement. References to the
 Credit Agreement in any document relating thereto shall be deemed to include
 this Amendment. This Amendment may be executed in counterparts.

         7.   Effectiveness. This Amendment shall be effective when (a) the
Agent has received a Fifty Thousand Dollar ($50,000) amendment fee and (b) the
parties have each received a fully executed copy of this Amendment.

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 IN WITNESS WHEREOF, Borrowers, the Agent and the Banks have caused this
 Amendment to be duly executed and delivered as of the date and year first above
 written.

                                            MARLTON TECHNOLOGIES, INC.

                                            By: /s/ Robert Ginsburg
                                                --------------------------------
                                            Name: Robert Ginsburg
                                            Title: Chief Executive Officer

                                            SPARKS EXHIBITS HOLDING CORPORATION

                                            By: /s/ Robert Ginsburg
                                                --------------------------------
                                            Name: Robert Ginsburg

                                            SPARKS EXHIBITS & ENVIRONMENTS CORP.

                                            By: /s/ Robert Ginsburg
                                                --------------------------------
                                            Name: Robert Ginsburg

                                            SPARKS EXHIBITS & ENVIRONMENTS, LTD.

                                            By: /s/ Robert Ginsburg
                                                --------------------------------
                                            Name: Robert Ginsburg

                                            SPARKS EXHIBITS & ENVIRONMENTS, INC.

                                            By: /s/ Robert Ginsburg
                                                --------------------------------
                                            Name: Robert Ginsburg

                                            SPARKS EXHIBITS & ENVIRONMENTS,
                                            INCORPORATED

                                            By: /s/ Robert Ginsburg
                                                --------------------------------
                                            Name: Robert Ginsburg

                                            SPARK SCENIC LTD.

                                            By: /s/ Robert Ginsburg
                                                --------------------------------
                                            Name: Robert Ginsburg

                                            DMS STORE FIXTURES LLC.

                                            By: /s/ Robert Ginsburg
                                                --------------------------------
                                            Name: Robert Ginsburg

                                            FIRST UNION NATIONAL BANK,
                                            as Bank and as Agent

                                            By: /s/ John L. Thomas
                                                --------------------------------
                                                   Vice President

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                               Update to Schedules

ss.  5.4 MTI has provided to the Bank its Form 10-K for the period ended
     December 31, 1999, and its Form 10-Qs for the fiscal quarters ended March
     31, June 30, and September 30, 2000.

ss.  5.16 GE Capital Corporation capital lease for up to $ $725,000 incurred
     pursuant to Section 6.4 of the Agreement.

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