<PAGE>


                                                                    EXHIBIT 10.1



                    ---------------------------------------



                         COMMON STOCK PURCHASE AGREEMENT


                                  BY AND AMONG


                            ERGO SCIENCE CORPORATION,


                              ESC MERGER SUB, INC.


                                       AND


                          COURT SQUARE CAPITAL LIMITED



                            DATED AS OF MAY 23, 2001



                     ---------------------------------------



<PAGE>


                                TABLE OF CONTENTS

<TABLE>
<CAPTION>

                                                                                            PAGE
<S>      <C>                                                                                <C>
1.       AUTHORIZATION AND SALE OF STOCK......................................................1

         1.1.     Authorization of Common Stock...............................................1
         1.2.     Sale of Common Stock........................................................1
         1.3.     Limitation On Other Issuances of Common Stock...............................2
         1.4.     Proceeds....................................................................2

2.       THE CLOSING..........................................................................2

3.       REPRESENTATIONS OF THE COMPANY.......................................................3

         3.1.     Organization and Corporate Power............................................3
         3.2.     Authorization...............................................................3
         3.3.     Effect of Transactions......................................................4
         3.4.     Brokerage...................................................................4

4.       REPRESENTATIONS OF THE PURCHASERS....................................................4

         4.1.     Accredited Investor.........................................................4
         4.2.     Investment..................................................................4
         4.3.     Suitability.................................................................4
         4.4.     Lack of Liquidity...........................................................5
         4.5.     Knowledge and Experience....................................................5
         4.6.     Access to Management........................................................5
         4.7.     Brokerage...................................................................5

5.       CONDITIONS TO THE OBLIGATIONS OF THE PURCHASER.......................................5

         5.1.     Accuracy of Representations and Warranties; Performance.....................5
         5.2.     Certificate.................................................................5
         5.3.     Stockholder Approval........................................................5
         5.4.     Consummation of Merger......................................................5
         5.5.     Purchaser Satisfaction with Acquisition.....................................5

6.       CONDITIONS TO THE OBLIGATIONS OF THE COMPANY.........................................6

         6.1.     Accuracy of Representations and Warranties; Performance.....................6
         6.2.     Certificate.................................................................6
         6.3.     Stockholder Approval........................................................6
         6.4.     Consummation of Merger......................................................6
         6.5.     Company Satisfaction with Acquisition.......................................6

7.       SUCCESSORS AND ASSIGNS...............................................................6

8.       SURVIVAL OF REPRESENTATIONS AND WARRANTIES...........................................6


                                             i
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9.       EXPENSES.............................................................................6

10.      NOTICES..............................................................................6

11.      NO CONDITIONS TO EFFECTIVENESS, ENTIRE AGREEMENT.....................................7

12.      AMENDMENTS AND WAIVERS...............................................................7

13.      COUNTERPARTS.........................................................................8

14.      CAPTIONS.............................................................................8

15.      SEVERABILITY.........................................................................8

16.      GOVERNING LAW........................................................................8

17.      TERMINATION AND EXPIRATION...........................................................8
</TABLE>



                                       ii

<PAGE>


                         COMMON STOCK PURCHASE AGREEMENT

         This Common Stock Purchase Agreement (this "AGREEMENT"), dated as of
May 23, 2001, is made by and among Ergo Science Corporation, a Delaware
corporation ("ERGO"), ESC Merger Sub, Inc., a Delaware corporation and
wholly-owned subsidiary of Ergo ("MERGER SUB"), and Court Square Capital
Limited, a Delaware corporation ("COURT SQUARE" and together with its permitted
assignees, the "PURCHASERS"). When used herein, the term "COMPANY" shall refer
to (i) Ergo prior to the effective time of the Merger (as hereinafter defined),
and (ii) Merger Sub at and after the effective time of the Merger.

         WHEREAS, subject to the approval of its stockholders, Ergo is
implementing certain restrictions on the transfer of its Common Stock (as
hereinafter defined) by means of the merger of Ergo with and into Merger Sub,
with Merger Sub being the surviving corporation and pursuant to which Merger Sub
shall change its name to "Ergo Science Corporation" (the "MERGER");

         WHEREAS, the Company wishes to acquire one or more operating businesses
(the "ACQUISITION") for such consideration as may then be agreed upon including,
without limitation, consideration in the form of cash;

         WHEREAS, the Company and Court Square entered into an agreement to
induce Court Square to assist the Company in identifying suitable targets for
the Acquisition by granting Court Square certain rights with respect to the
issuance and sale of shares of Common Stock (as defined herein) to finance the
Acquisition (the "ORIGINAL AGREEMENT"); and

         WHEREAS, the parties wish to, and hereby do, amend and restate the
Original Agreement as follows.

         NOW, THEREFORE, in consideration of the mutual promises and covenants
contained in this Agreement, and intending to be legally bound by the terms and
conditions of this Agreement, the parties hereto hereby agree as follows:

1.       AUTHORIZATION AND SALE OF STOCK.

         1.1. AUTHORIZATION OF COMMON STOCK. The Company has duly authorized the
sale and issuance of up to 7,500,000 shares of its Common Stock, par value $0.01
per share (the "COMMON STOCK").

         1.2. SALE OF COMMON STOCK.

                  (a) Subject to the terms and conditions of this Agreement, at
         the Closing, the Company shall issue and sell to the Purchasers, and
         the Purchasers shall purchase from the Company that number of shares of
         Common Stock (the "COMMON SHARES") as may be determined by mutual
         agreement of the parties, up to an aggregate maximum of 7,500,000
         shares (such maximum number subject to adjustment as provided below) of
         Common Stock at a purchase price per share equal to the SUM of (i)
         $1.15 AND (ii) the Book Value Increase (as defined below) per share


                                       1
<PAGE>


         (such purchase price per share subject to adjustment as provided below,
         the "PURCHASE PRICE"). The Purchasers shall pay the Purchase Price to
         the Company for the Common Shares, and such Common Shares shall be sold
         and issued, in accordance with Section 2 of this Agreement.

                  (b) The maximum number of Common Shares subject to issuance
         and sale pursuant to this Section 1.2, the Purchase Price and the Book
         Value Per Share (as defined below) shall each be equitably adjusted for
         any stock split, stock dividend, combination of shares, reorganization,
         recapitalization, reclassification or similar event involving or
         affecting the Common Stock (including, without limitation, the effect
         of the Merger).

                  (c) For purposes of this Section 1.2: (i) the term "BOOK VALUE
         INCREASE" shall mean any increase in the Book Value Per Share occurring
         between May 23, 2001 and the Closing Date attributable to (A) the
         Company's receipt of Cash in consideration of the sale of the Company's
         non-Cash assets or (B) the reduction or elimination of the Liquidation
         Preference; (ii) the term "BOOK VALUE PER SHARE" shall mean the
         QUOTIENT of (A) the Company's then total amount of assets LESS the SUM
         of its then total amount of liabilities AND the Liquidation Preference
         DIVIDED BY (B) the number of shares of the Company's Common Stock then
         outstanding; (iii) the term "LIQUIDATION PREFERENCE" shall mean the
         then aggregate accrued liquidation preference on all outstanding shares
         of the Company's preferred stock; and (iv) the term "CASH" shall mean
         cash, cash equivalents and short-term investments.

         1.3. LIMITATION ON OTHER ISSUANCES OF COMMON STOCK. The Company hereby
covenants and agrees that it shall not issue any shares of Common Stock or other
security exercisable for or convertible into Common Stock to any party (other
than as specifically contemplated herein) in connection with the financing of an
Acquisition of a business introduced to the Company by Court Square either
directly or indirectly (i.e. through an intermediary introduced to the Company
by Court Square) unless and until either (i) the Company has issued and sold all
of the Common Shares to the Purchasers or (ii) the Purchasers have declined to
purchase the Common Shares offered to them pursuant to this Agreement in
connection with such Acquisition.

         1.4. PROCEEDS. Proceeds from the sale of the Common Shares may be used
for any corporate purpose, including without limitation as consideration for an
Acquisition and/or general working capital purposes.

2. THE CLOSING. The closing of the sale and purchase of the Common Shares
pursuant to this Agreement shall take place, if at all, in such place, on such
date and at such time as shall be mutually agreed by the Company and the
Purchasers (the "CLOSING"). The date of the Closing is hereinafter referred to
as the "CLOSING DATE." At the Closing, the Company shall deliver to each
Purchaser a certificate representing the number of Common Shares purchased by
such Purchaser as provided in Section 1.2 hereof registered in the name of the
Purchaser. The Purchase Price shall be paid by wire transfer, certified or
cashier's check or other method acceptable to the Company and which shall
facilitate the consummation of the


                                       2
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Acquisition. If, at the Closing, any of the conditions specified in Section 5 of
this Agreement shall not have been fulfilled, each Purchaser shall, at its
election, be relieved of all of its obligations under this Agreement without
thereby waiving any other right it may have by reason of such failure or such
non-fulfillment. If, at the Closing, any of the conditions specified in Section
6 of this Agreement shall not have been fulfilled, the Company shall, at its
election, be relieved of all of its obligations under this Agreement without
thereby waiving any other right it may have by reason of such failure or such
non-fulfillment.

3. REPRESENTATIONS OF THE COMPANY. The Company hereby represents and warrants to
the Purchasers as follows:

         3.1. ORGANIZATION AND CORPORATE POWER. The Company is a corporation
duly organized, validly existing and in corporate good standing under the laws
of the State of Delaware and is qualified to do business as a foreign
corporation in each jurisdiction in which such qualification is required, except
where the failure to be so qualified would not have a material and adverse
effect on the business, operations, financial condition, assets, prospects,
liabilities or contractual rights of the Company (a "MATERIAL ADVERSE EFFECT").
The Company has all required corporate power and authority to own its property,
to carry on its business as presently conducted or contemplated, to enter into
and perform this Agreement and the other agreements, documents and instruments
contemplated hereby (collectively with this Agreement, the "TRANSACTION
DOCUMENTS"), and generally to carry out the transactions contemplated hereby.
The Company is not in violation of any term of its Certificate of Incorporation
or By-laws, or in violation of any term of any agreement, instrument, judgment,
decree, order, statute, rule or government regulation applicable to the Company
or to which the Company is a party, where any violation, noncompliance or
default would result in a Material Adverse Effect.

         3.2. AUTHORIZATION. Other than obtaining the approval of the Company's
stockholders with regard to the issuance of the Common Shares:

                  (a) The Transaction Documents are valid and binding
         obligations of the Company, enforceable against the Company in
         accordance with their terms, except as may be limited by (A) applicable
         bankruptcy, insolvency, reorganization or other laws of general
         application relating to or affecting the enforcement of creditors'
         rights generally and (B) the effects of rules of law governing the
         availability of equitable remedies.

                  (b) The execution, delivery and performance of the Transaction
         Documents have been duly authorized by all necessary corporate or other
         action of the Company.

                  (c) The issuance, sale and delivery of the Common Shares in
         accordance with this Agreement have been, or will be prior to the
         Closing, duly authorized and reserved for issuance, as the case may be,
         by all necessary corporate action on the part of the Company.

                  (d) The Common Shares, when so issued, sold and delivered
         against payment therefor in accordance with the provisions of this
         Agreement will be duly and validly issued, fully paid and
         non-assessable.


                                       3
<PAGE>


                  (e) No consent, approval or authorization of, or designation,
         declaration or filing with, any governmental authority or any other
         person or entity is required of the Company in connection with the
         execution and delivery of the Transaction Documents, or the issuance,
         sale and delivery of the Common Shares in accordance with the terms of
         this Agreement or the consummation of any other transaction
         contemplated hereby or by the other Transaction Documents.

         3.3. EFFECT OF TRANSACTIONS. The execution, delivery and performance by
the Company of the Transaction Documents will not conflict with or result in any
default under any material contract, obligation or commitment of the Company, or
any provision of the Company's Certificate of Incorporation or By-laws, or in
any corporate restriction of the Company or the creation of any lien, charge or
encumbrance of any nature upon any of the properties or assets of the Company
which could have a Material Adverse Effect. The Company's execution and delivery
of the Transaction Documents and its performance of the transactions
contemplated thereby will not violate any instrument, agreement, judgment,
decree, order, statute, rule or regulation of any federal, state or local
government or agency applicable to the Company which could reasonably be
expected to have a Material Adverse Effect.

         3.4. BROKERAGE. There are no claims for brokerage commissions, finder's
fees or similar compensation in connection with the transactions contemplated by
this Agreement based on any arrangement or agreement made by or on behalf of the
Company, except as described herein.

4. REPRESENTATIONS OF THE PURCHASERS. Each Purchaser severally represents and
warrants to the Company, as follows:

         4.1. ACCREDITED INVESTOR. Except as otherwise disclosed to the Company,
it is an "accredited investor" as such term is defined in Regulation D under the
Securities Act of 1933, as amended (the "SECURITIES ACT").

         4.2. INVESTMENT. It is acquiring Common Shares for its own account for
investment and not with a view to, or for sale in connection with, any
distribution thereof, nor with any present intention of distributing or selling
the same, and it has no present or contemplated agreement, undertaking,
arrangement, obligation, indebtedness or commitment providing for the
disposition thereof.

         4.3. SUITABILITY. It understands and has fully considered for purposes
of this investment the risks of this investment and understands that (i) this
investment is suitable only for an investor who is able to bear the economic
consequences of losing its entire investment; (ii) the Company is substantially
similar to an early-stage enterprise with no operating history, and no revenues
or net income from operations to date; (iii) the purchase of Common Shares is a
speculative investment which involves a high degree of risk of loss of the
entire investment; and (iv) there are substantial restrictions on the
transferability of the Common Shares, and accordingly, it may not be possible
for it to liquidate its investment in case of emergency or otherwise.


                                       4
<PAGE>


         4.4. LACK OF LIQUIDITY. It is able (i) to bear the economic risk of
this investment, (ii) to hold the Common Shares for an indefinite period of
time, and (iii) presently to afford a complete loss of its investment. It has
sufficient liquid assets so that the illiquidity associated with this investment
will not cause any undue financial difficulties or affect its ability to provide
for its current needs and possible financial contingencies, and that its
commitment to all speculative investments (including the investment contemplated
by this Purchase Agreement) is reasonable in relation to its net worth or
investment portfolio.

         4.5. KNOWLEDGE AND EXPERIENCE. It has such knowledge and experience in
financial and business matters that it is capable of evaluating the merits and
risks of an investment in the Common Shares and of making an informed investment
decision and can bear a complete loss of its investment.

         4.6. ACCESS TO MANAGEMENT. It, in making its decision to purchase
Common Shares, has been given the opportunity to ask questions of, and to
receive answers from, management and other persons acting on behalf of the
Company concerning the Company and the terms and conditions of transaction
contemplated by this Agreement, and to obtain any additional information, to the
extent such persons possess such information.

         4.7. BROKERAGE. There are no claims for brokerage commissions, finder's
fees or similar compensation in connection with the transactions contemplated by
this Agreement based on any arrangement or agreement made by or on behalf of
such Purchaser, except as described herein.

5. CONDITIONS TO THE OBLIGATIONS OF THE PURCHASER. The obligations of each
Purchaser under this Agreement are subject to the fulfillment, or the waiver by
such Purchaser, of the conditions set forth in this Section 5 on or before the
Closing Date.

         5.1. ACCURACY OF REPRESENTATIONS AND WARRANTIES; PERFORMANCE. The
representations and warranties of the Company contained in Section 3 of this
Agreement shall be true on and as of the Closing Date with the same effect as
though such representation and warranty had been made on and as of that date,
other than as would not, taken as a whole, have an Material Adverse Effect. The
Company shall have performed and complied with all agreements and conditions
contained in this Agreement required to be performed or complied with by the
Company prior to or at the Closing.

         5.2. CERTIFICATE. The Company shall have delivered to each Purchaser a
certificate, executed by the President of the Company as of the Closing Date,
certifying to the fulfillment of the conditions to the Purchasers' obligations
under this Agreement set forth in Section 5.1.

         5.3. STOCKHOLDER APPROVAL. The stockholders of Ergo shall have approved
(i) the Merger and (ii) the issuance of Common Shares contemplated herein.

         5.4. CONSUMMATION OF MERGER. The Merger shall have been consummated.

         5.5. PURCHASER SATISFACTION WITH ACQUISITION. The Acquisition shall be
acceptable in all respects to such Purchaser in its sole discretion.


                                       5
<PAGE>


6. CONDITIONS TO THE OBLIGATIONS OF THE COMPANY. The obligations of the Company
under this Agreement are subject to the fulfillment, or the waiver in writing by
the Company, of the conditions set forth in this Section 6 on or before each
Closing Date.

         6.1. ACCURACY OF REPRESENTATIONS AND WARRANTIES; PERFORMANCE. The
representations and warranties of each Purchaser contained in Section 4 shall be
true on and as of the Closing Date with the same effect as though such
representations and warranties had been made on and as of that date. Each
Purchaser shall have performed and complied with all agreements contained in
this Agreement required to be performed and complied with by it prior to or at
the Closing.

         6.2. CERTIFICATE. Each Purchaser shall have delivered to the Company a
certificate, duly executed by or on behalf of it as of the Closing Date,
certifying to the fulfillment of the conditions to the Company's obligations
under this Agreement set forth in Section 6.1.

         6.3. STOCKHOLDER APPROVAL. The stockholders of Ergo shall have approved
(i) the Merger and (ii) the issuance of the Common Shares contemplated herein.

         6.4. CONSUMMATION OF MERGER. The Merger shall have been consummated.

         6.5. COMPANY SATISFACTION WITH ACQUISITION. The Acquisition shall be
acceptable in all respects to the Company in its sole discretion.

7. SUCCESSORS AND ASSIGNS. No assignment or transfer of this Agreement or any
right or privilege hereunder by any party, including any assignment by operation
of law pursuant to a merger, liquidation, foreclosure, or involuntary sale in
bankruptcy, shall be effective or binding on the other party without such other
party's prior written consent. Notwithstanding the foregoing, (i) Ergo may
assign its rights and obligations hereunder to Merger Sub in connection with the
Merger and (ii) Court Square may assign its rights and obligations, in whole or
in part, to any of its "affiliates" (as such term is defined in Regulation D
under the Securities Act) or any employee or director of Court Square of any
such affiliate. The provisions of this Agreement shall bind and inure to the
benefit of the respective permitted successors, assigns, heirs, executors, and
administrators of the parties hereto.

8. SURVIVAL OF REPRESENTATIONS AND WARRANTIES. All representations, warranties
and covenants shall terminate at, and be of no further force and effect after,
the Closing.

9. EXPENSES. Each party shall bear its own costs and expenses in connection with
the transactions contemplated hereby.

10. NOTICES. All notices, requests, consents and other communications under this
Agreement shall be in writing and shall be delivered by hand, by telecopier, by
express overnight courier service or mailed by first class mail, postage
prepaid, as follows:


                                       6
<PAGE>


If to Purchaser, addressed to:

         Court Square Capital Limited
         c/o Citicorp Venture Capital, Ltd.
         399 Park Avenue
         New York, NY 10043
         Attn: President
         Telephone: (212) 559-3765
         Fax:       (212) 888-2940

If to Company, addressed to:

         Ergo Science Corporation
         790 Turnpike Street; Suite 205
         North Andover, MA 01845
         Attn: President
         Telephone: (978) 974-9474
         Fax:       (978) 974-0688

With a copy to:

         Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C.
         One Financial Center
         Boston, MA 02111
         Attention: Douglas A. Zingale, Esq.
         Telephone: (617) 542-6000
         Fax:       (617) 542-2241

or to such other place and with such other copies as either party may designate
as to itself by written notice to the other.

         Notices provided in accordance with this Section 10 shall be deemed
delivered upon personal delivery, receipt by telecopier or overnight mail, or 48
hours after deposit in the mail in accordance with the above.

11. NO CONDITIONS TO EFFECTIVENESS, ENTIRE AGREEMENT. This Agreement, together
with the instruments and other documents hereby contemplated to be executed and
delivered in connection herewith, contains the entire agreement and
understanding of the parties hereto, and supersedes any prior agreements or
understandings between or among them, with respect to the subject matter hereof,
including without limitation the Original Agreement.

12. AMENDMENTS AND WAIVERS. Except as otherwise expressly set forth in this
Agreement, any term of this Agreement may be amended and the observance of any
term of this Agreement may be waived (either generally or in a particular
instance and either retroactively or prospectively), with the written consent of
the Company and the Purchasers. No waivers of or exceptions to any term,
condition or provision of this Agreement, in any one or more instances, shall be
deemed to be, or construed as, a further or continuing waiver of any such term,
condition or provision.


                                       7
<PAGE>


13. COUNTERPARTS. This Agreement may be executed in one or more counterparts,
each of which shall be deemed an original, but all of which together shall
constitute one and the same instrument.

14. CAPTIONS. The captions of the sections, subsections and paragraphs of this
Agreement have been added for convenience only and shall not be deemed to be a
part of this Agreement.

15. SEVERABILITY. Each provision of this Agreement shall be interpreted in such
manner as to validate and give effect thereto to the fullest lawful extent, but
if any provision of this Agreement is determined by a court of competent
jurisdiction to be invalid or unenforceable under applicable law, such provision
shall be ineffective only to the extent so determined and such invalidity or
unenforceability shall not affect the remainder of such provision or the
remaining provisions of this Agreement.

16. GOVERNING LAW. This Agreement shall be governed by, interpreted, construed
and enforced in accordance with, the substantive laws of the State of Delaware,
without reference to principles of conflict of laws.

17. TERMINATION AND EXPIRATION. Unless otherwise terminated earlier by mutual
agreement of the Company and Court Square, the term of this Agreement shall
expire on the second anniversary of the date hereof.


                                       8
<PAGE>


         IN WITNESS WHEREOF, Ergo, Merger Sub and Court Square have executed
this Common Stock Purchase Agreement as of the day and year first above written.


                                              ERGO SCIENCE CORPORATION


                                              By:  /s/ David R. Burt
                                                   ---------------------------
                                                   Name:  David R. Burt
                                                   Title: President




                                              ESC MERGER SUB, INC.


                                              By:  /s/ David R. Burt
                                                   ---------------------------
                                                   Name:  David R. Burt
                                                   Title: President




                                              COURT SQUARE CAPITAL LIMITED


                                              By:  /s/ Thomas F. McWilliams
                                                   ---------------------------
                                                   Name:  Thomas F. McWilliams
                                                   Title:



                                       9