<PAGE>

                                                                    EXHIBIT 10.1

                 SECOND AMENDMENT TO FOURTH AMENDED AND RESTATED
                     REVOLVING CREDIT AND SECURITY AGREEMENT

          This Second Amendment to Fourth Amended and Restated Revolving Credit
and Security Agreement (the "Amendment") is made this 5th day of March, 2003, by
and among WinCup Holdings, Inc., Radnor Chemical Corporation, StyroChem U.S.,
Ltd., Radnor Holdings Corporation, Radnor Delaware II, Inc., StyroChem Delaware,
Inc., WinCup Texas, Ltd., StyroChem GP, L.L.C., StyroChem LP, L.L.C., WinCup GP,
L.L.C., and WinCup LP, L.L.C. (each individually a "Borrower" and collectively,
"Borrowers"), and PNC Bank, National Association ("PNC"), as Lead Arranger and
Administrative Agent (defined below), Fleet Capital Corporation ("Fleet"), as
Documentation Agent (defined below) and Lenders (defined below).

                                   BACKGROUND

          A.   On December 26, 2001, Borrowers, the financial institutions which
are now or which hereafter become a party hereto (individually, a "Lender" and
collectively, the "Lenders"), and PNC, as agent for Lenders (PNC in such
capacity, the "Agent") entered into a certain Fourth Amended and Restated
Revolving Credit and Security Agreement (as amended, modified, renewed,
extended, replaced or substituted from time to time, the "Loan Agreement") to
reflect certain financing arrangements between the parties thereto. The Loan
Agreement and all other documents executed in connection therewith are
collectively referred to as the "Existing Financing Agreements." All capitalized
terms not otherwise defined herein shall have the meaning ascribed thereto in
the Loan Agreement. In the case of a direct conflict between the provisions of
the Loan Agreement and the provisions of this Amendment, the provisions hereof
shall prevail.

          B.   Borrowers and Agent modified certain definitions, terms and
conditions contained in the Loan Agreement pursuant to that (i) certain First
Amendment to Revolving Credit and Security Agreement dated February 4, 2002 to
facilitate the execution of a Commitment Transfer Supplement by and between
Lenders and Fleet Capital Corporation and (ii) certain Letter Agreement, dated
as of March 21, 2002, among Borrowers, Agent and Lenders.

          C.   The Borrowers have requested and the Agent has agreed to modify
certain definitions, terms and conditions in the Loan Agreement to increase the
credit facilities provided therein.

          D.   The parties have agreed, subject to the terms and conditions of
this Amendment, to modify and amend the Existing Financing Agreements.

     NOW THEREFORE, with the foregoing background hereinafter deemed
incorporated by reference herein and made part hereof, the parties hereto,
intending to be legally bound, promise and agree as follows:

<PAGE>

     1.   The title page of the Loan Agreement and the Preamble shall be amended
to read "Fourth Amended and Restated Revolving Credit, Term Loan and Security
Agreement."

     2.   As of the effective date of this Amendment, Fleet is hereby appointed
as Documentation Agent ("Documentation Agent") and PNC, in addition to its
appointment as an Agent is additionally appointed as Lead Arranger and
Administrative Agent ("Lead Arranger and Administrative Agent") under the terms
of the Existing Financing Agreements.

     3.   Section I of the Loan Agreement shall be amended as follows:

          (a)  There shall be added to Section I of the Loan Agreement the
following definitions:

               "Excess Cash Flow" shall mean for any fiscal period, EBITDA of
               Radnor on a Consolidated Basis for such fiscal period, minus
               non-financed capital expenditures made by Radnor on a
               Consolidated Basis during such fiscal period, minus taxes paid in
               cash by Radnor on a Consolidated Basis during such fiscal period,
               minus interest paid in cash by Radnor on a Consolidated Basis
               during such fiscal period, minus scheduled principal payments
               made by Radnor on a Consolidated Basis for Indebtedness of Radnor
               on a Consolidated Basis during such fiscal period, plus decreases
               in working capital of Radnor on a Consolidated Basis for such
               fiscal period, minus increases in working capital of Radnor on a
               Consolidated Basis during such fiscal period.

               "Funded Debt to EBITDA Ratio" shall mean with respect to such
               fiscal period the ratio of (a) all Indebtedness for Borrowed
               Money (less cash on hand) to (b) EBITDA.

               "Funding Date" shall mean the date on which the conditions
               precedent specified in Sections 14 and 15 of this Amendment have
               been satisfied.

               "Maximum Revolving Advance Amount" shall mean Forty Five Million
               Dollars ($45,000,000).

               "Mortgage" shall mean those mortgages on the Mortgaged Properties
               securing the original principal amount of Forty Five Million
               Dollars ($45,000,000) together with all extensions, renewals,
               amendments, supplements, modifications, substitutions and
               replacements thereto and thereof.

               "Mortgaged Properties" shall mean that certain real property
               owned by WinCup Holdings, Inc. generally known as 1425 Hawthorne
               Lane, 1351 Hawthorne Lane and 1000 Harvester Lane, West Chicago,
               Illinois and that certain real property owned by WinCup Holdings,
               Inc. generally known as 190 Liberty Street, Metuchen, New Jersey,
               each as more particularly described in the Mortgages.

                                        2

<PAGE>

               "New M&E Appraisal" shall mean that certain orderly liquidation
               value appraisal dated as of January 29, 2003 prepared by Plastic
               Asset Solutions.

               "New Real Property Appraisals" shall mean those certain fair
               market value appraisals currently being prepared by Cushman &
               Wakefield and Cooney Valuation Group for each of the Mortgaged
               Properties.

               "OLV of Unencumbered M&E" shall mean the appraised orderly
               liquidation value of certain of Borrowers' Equipment as listed in
               the New M&E Appraisal, which is not encumbered by a Lien (other
               than a Permitted Encumbrance) as determined in accordance with
               the New M&E Appraisal.

               "Term Loan" shall mean the Advances made pursuant to Section 2.4
               hereof.

               "Term Loan Rate" shall mean an interest rate per annum equal to
               (a) the sum of the Alternate Base Rate plus twenty-five (25)
               basis points, with respect to Domestic Rate Loans, and (b) the
               sum of the Eurodollar Rate plus the Applicable Margin with
               respect to Eurodollar Rate Loans.

               "Term Note" shall mean, collectively, the promissory notes
               described in Section 2.4 hereof.

          (b)  The following definitions shall be deleted in their entirety and
replaced as follows:

               "Advances" shall mean and include the Revolving Advances, Letters
               of Credit as well as the Term Loan.

               "Applicable Margin" for any period shall be determined by the
               Fixed Charge Coverage Ratio of Radnor on a Consolidated Basis
               calculated for the most recent fiscal quarter with respect to the
               four fiscal quarters then ended which shall be increased or
               decreased from time to time, as the case may be, so long as no
               Default or Event of Default shall have occurred and be
               continuing, as of the first day of each fiscal quarter following
               the fiscal quarter reported upon in the financial statements
               delivered pursuant to Sections 9.7 and 9.8 hereof. The Applicable
               Margin with respect to Eurodollar Rate Loans shall be the
               percentage set forth below as corresponds to the applicable ratio
               set forth below:

                                        3

<PAGE>

                                                  Revolving
                                                  Advances            Term Loan
                                                 Eurodollar           Eurodollar
          Fixed Charge Coverage Ratio            Rate Margin         Rate Margin
          ---------------------------            -----------         -----------
          Less than 1.5:1                           2.50%                2.75%
          1.50:1 to 1.74:1                          2.25%                2.50%
          1.75:1 or greater                         2.00%                2.25%

     In the event of a Default or Event of Default hereunder, the Applicable
Margin shall be (a) 2.50% with respect to Revolving Advances and (b) 2.75% with
respect to the Term Loan.

                    "Collateral" shall mean and include:

                    (a)  all Receivables;

                    (b)  all Equipment (excluding Equipment as set forth in
                    Schedule 1.1);

                    (c)  all General Intangibles;

                    (d)  all Inventory;

                    (e)  all Investment Property (excluding the stock or other
                    ownership interests of any Subsidiary of Radnor or any other
                    Borrower);

                    (f)  all Mortgaged Properties;

                    (g)  all of each Borrower's right, title and interest in and
                    to (i) its respective goods and other property including,
                    but not limited to, all merchandise returned or rejected by
                    Customers, relating to or securing any of the Receivables;
                    (ii) all of each Borrower's rights as a consignor, a
                    consignee, an unpaid vendor, mechanic, artisan, or other
                    lienor, including stoppage in transit, setoff, detinue,
                    replevin, reclamation and repurchase; (iii) all additional
                    amounts due to any Borrower from any Customer relating to
                    the Receivables; (iv) other property, including warranty
                    claims, relating to any goods securing this Agreement; (v)
                    all of each Borrower's contract rights, rights of payment
                    which have been earned under a contract right, instruments
                    (including promissory notes), documents, chattel paper
                    (including electronic chattel paper), warehouse receipts,
                    deposit accounts, letters of credit, and money; (vi) all
                    commercial tort claims (whether now existing or hereafter
                    arising); and (vii) if and when obtained by any Borrower,
                    all real and personal property of third parties in which
                    such

                                        4

<PAGE>

                    Borrower has been granted a lien or security interest as
                    security for the payment or enforcement of Receivables;

                    (h)  all of each Borrower's ledger sheets, ledger cards,
                    files, correspondence, records, books of account, business
                    papers, computers, computer software (owned by any Borrower
                    or in which it has an interest), computer programs, tapes,
                    disks and documents relating to (a), (b), (c), (d), (e), (f)
                    or (g) of this Paragraph; and

                    (i)  all proceeds and products of (a), (b), (c), (d), (e),
                    (f), (g) or (h) in whatever form, including, but not limited
                    to: cash, deposit accounts (whether or not comprised solely
                    of proceeds), certificates of deposit, insurance proceeds
                    (including hazard, flood and credit insurance), negotiable
                    instruments and other instruments for the payment of money,
                    chattel paper, security agreements, documents, eminent
                    domain proceeds, condemnation proceeds and tort claim
                    proceeds.

               "Contract Rate" shall mean, as applicable, the Revolving Interest
               Rate or the Term Loan Rate.

               "Fixed Charge Coverage Ratio" for any period shall mean with
               respect to any fiscal period the ratio of (a) EBITDA minus
               unfinanced capital expenditures and all distributions and
               dividends made during such period to (b) all Debt Payments made
               during such period.

               "Maximum Loan Amount" shall mean Ninety Million Dollars
               ($90,000,000) less repayments of the Term Loan.

               "Note" shall mean, collectively, the Revolving Credit Note and
               the Term Note.

               "Revolving Advances" shall mean Advances made other than Letters
               of Credit and the Term Loan.

               "Revolving Interest Rate" shall mean an interest rate per annum
               equal to (a) the Alternate Base Rate with respect to Domestic
               Rate Loans and (b) the Eurodollar Rate plus the Applicable Margin
               with respect to Eurodollar Rate Loans.

               "Senior Notes and Second Senior Notes" shall mean, until closing
               and funding occurs under the Bond Refinancing (as defined below),
               the 10% Senior Notes due 2003 and the 10% Series B Senior Notes
               due 2003 issued by Radnor pursuant to the Indenture and Second
               Indenture, respectively; and at any time after the closing and
               funding of the Bond Refinancing, shall collectively mean the
               notes due under the Bond Refinancing documents issued by Radnor
               pursuant to the indenture and

                                        5

<PAGE>

               any notes issued in exchange or substitution therefor.

               "Term" shall mean the Effective Date through March 4, 2008.

               "Undrawn Availability" at a particular date shall mean an amount
               equal to (a) the lesser of (i) the Formula Amount or (ii) the
               Maximum Revolving Advance Amount, minus (b) the sum of (i) the
               outstanding amount of Advances (other than the Term Loan), plus
               (ii) all amounts due and owing to Borrowers' trade creditors
               which are outstanding more than sixty (60) days beyond normal
               trade terms, plus (iii) fees and expenses for which Borrowers are
               liable hereunder but which have not been paid or charged to
               Borrowers' Account.

     4.   Section II of the Loan Agreement shall be amended as follows:

          (a)  Section 2.1(a) shall be deleted in its entirety and replaced as
follows:

               2.1 Revolving Advances.

                    (a)  Subject to the terms and conditions set forth in this
                    Agreement, including, without limitation, Section 2.1(b),
                    each Lender, severally and not jointly, agrees to make
                    Revolving Advances to Borrowers in accordance with the
                    procedures provided for herein in an aggregate amount
                    outstanding at any time not greater than such Lender's
                    Commitment Percentage of the Borrowing Base (as defined
                    below) minus the undrawn or unreimbursed amount of
                    outstanding Letters of Credit unless Borrowers have
                    deposited with Agent cash collateral in such amounts and in
                    accordance with Section 3.2. For purposes hereof, "Borrowing
                    Base" shall mean the lesser of (x) the Maximum Revolving
                    Advance Amount or (y) the sum of:

                    (i) up to 85%, subject to the provisions of Section 2.1(b)
                    hereof ("Receivables Advance Rate"), of Eligible
                    Receivables, plus

                    (ii) the lesser of (x) $1,000,000 or (y) up to 85%, subject
                    to the provisions of 2.1(b) hereof ("Canadian Receivables
                    Advance Rate"), of Eligible Canadian Receivables, plus

                    (iii) the lesser of (x) $25,000,000 or (y) up to 60%,
                    subject to the provisions of Section 2.1(b) hereof
                    ("Inventory Advance Rate"), of Eligible Inventory of
                    Borrowers (the Receivables Advance Rate, the Canadian
                    Receivables Advance Rate and the Inventory Advance Rate
                    shall be referred to, collectively, as the "Advance Rates"),
                    minus

                    (iv) such reserves as Agent may, in a commercially
                    reasonable manner, reasonably deem proper and necessary.

                                        6

<PAGE>

                     The amount derived from the sum of Sections 2.1(a)(y)(i),
                     (ii) and (iii) minus (iv) at any time and from time to time
                     shall be referred to as the "Formula Amount". The Revolving
                     Advances shall be evidenced by one or more secured
                     promissory notes (collectively, the "Revolving Credit
                     Note") substantially in the form attached hereto as Exhibit
                     2.1(a).

               (b)   Section 2.4 shall be deleted in its entirety and replaced
as follows:

                     2.4  Term Loan. Subject to the terms and conditions of this
                     Agreement, each Lender, severally and not jointly, will
                     make a Term Loan to Borrowers in the sum equal to such
                     Lender's Commitment Percentage of Forty Five Million and
                     00/100 Dollars ($45,000,000), which is approximately equal
                     to the sum of (i) 80% of the OLV of Unencumbered M&E plus
                     (ii) 70% of the value of the Mortgaged Properties based on
                     the New Real Property Appraisals. The Term Loan shall be
                     advanced on the Funding Date and shall be, with respect to
                     principal, payable commencing on June 1, 2003 and
                     continuing on the first day of each September, December,
                     March and June thereafter as follows, subject to
                     acceleration upon the occurrence of an Event of Default
                     under this Agreement or termination of this Agreement: (a)
                     eight (8) consecutive quarterly payments each in the amount
                     of One Million One Hundred Twenty Five Thousand and 00/100
                     Dollars ($1,125,000) followed by; (b) four (4) consecutive
                     quarterly payments each in the amount of One Million Six
                     Hundred Eighty Seven Thousand Five Hundred and 00/100
                     Dollars ($1,687,500) followed by; (c) seven (7) consecutive
                     quarterly payments each in the amount of Two Million Two
                     Hundred Fifty Thousand and 00/100 Dollars ($2,250,000)
                     followed by; (d) a final payment of all outstanding
                     principal and interest on the Term Loan plus all fees and
                     expenses then due and owing at the expiration of the Term,
                     and shall be evidenced by one or more secured promissory
                     notes (collectively, the "Term Note") in substantially the
                     form attached hereto as Exhibit 2.4.

               (c)   Section 2.5 shall be deleted in its entirety and replaced
as follows:

                     2.5  Maximum Advances. The aggregate balance of Revolving
                     Advances outstanding at any time shall not exceed the
                     lesser of (a) the Maximum Revolving Advance Amount less
                     outstanding Letters of Credit or (b) the Formula Amount
                     less outstanding Letters of Credit.

               (d)   Section 2.6 (a) shall be deleted in its entirety and
replaced as follows:

                     (a)  The Revolving Advances shall be due and payable in
                     full on the last day of the Term subject to earlier
                     prepayment as herein provided. The Term Loan shall be due
                     and payable as provided in Section 2.4 hereof and in the
                     Term Note, subject to mandatory prepayments as herein
                     provided.

                                        7

<PAGE>

               (e)   The reference in 2.9(b) to "$5,000,000" shall be amended to
read "$6,000,000".

               (f)   Section 2.13(a) shall be amended by adding the following
sentence:

                     "The Term Loan shall be advanced according to the
                     Commitment Percentages of the Lenders."

               (g)   Section 2.13(b) shall be amended by adding the following
sentence after the first full sentence:

                     "Each payment (including each prepayment) by Borrowers on
                     account of the principal of and interest on the Term Note,
                     shall be applied to, that portion of the Term Loan
                     evidenced by the Term Note pro rata according to the
                     Commitment Percentages of the Lenders."

               (h)   Section 2.14 shall be deleted in its entirety and replaced
as follows:

                     2.14  Mandatory Prepayments.

                     (a)  To the extent required by Section 4.3 hereof, when any
                     Borrower sells or otherwise disposes of any Collateral
                     other than Inventory in the ordinary course of business,
                     Borrowers shall repay the Advances in an amount equal to
                     the net proceeds of such sale (i.e., gross proceeds less
                     taxes arising from such sale and the reasonable costs of
                     such sales or other dispositions), such repayments to be
                     made promptly but in no event more than one (1) Business
                     Day following receipt of such net proceeds, and until the
                     date of payment, such proceeds shall be held in trust for
                     Agent. The foregoing shall not be deemed to be implied
                     consent to any such sale otherwise prohibited by the terms
                     and conditions hereof. Such repayments shall be applied (x)
                     first, to the outstanding principal installments of the
                     Term Loan in the inverse order of the maturities thereof
                     and (y) second, to the remaining Advances in such order as
                     Agent may determine, subject to Borrower's ability to
                     reborrow Revolving Advances in accordance with the terms
                     hereof.

                     (b)  Borrowers shall prepay the outstanding amount of the
                     Advances in an amount equal to thirty three percent (33%)
                     of Excess Cash Flow for each fiscal year (not to exceed in
                     any given fiscal year an amount equal to the greater of (i)
                     $4,500,000 or (ii) the scheduled principal amount amortized
                     on account of the Term Loan for that year), payable upon
                     delivery of the financial statements to Agent referred to
                     in and required by Section 9.7 for such fiscal year but in
                     any event not later than one hundred twenty (120) days
                     after the end of each such fiscal year, which amount shall
                     be applied to the outstanding principal installments of the
                     Term Loan in the inverse order of the maturities thereof;
                     provided however, Borrowers' requirement to make the Excess
                     Cash Flow payments hereunder shall cease when the
                     outstanding principal amount due under the Term Loan falls
                     below Thirty

                                        8

<PAGE>

                     Million Dollars ($30,000,000). In the event that the
                     financial statement referenced herein is not so delivered,
                     then a calculation based upon estimated amounts shall be
                     made by Agent upon which calculation Borrowers shall make
                     the prepayment required by this Section 2.14(b), subject to
                     adjustment when the financial statement is delivered to
                     Agent as required hereby. The calculation made by Agent
                     shall not be deemed a waiver of any rights Agent or Lenders
                     may have as a result of the failure by Borrowers to deliver
                     such financial statement.

         5.    Section III of the Loan Agreement shall be amended as follows:

               (a)   Section 3.1 of the Loan Agreement shall be deleted in its
entirety and replaced as follows:

                     3.1 Interest. Interest on Advances shall be payable in
                     arrears on the first day of each month with respect to
                     Domestic Rate Loans and, with respect to Eurodollar Rate
                     Loans, at the end of each Interest Period or, for
                     Eurodollar Rate Loans with an Interest Period in excess of
                     three months, at the earlier of (a) each three months on
                     the anniversary date of the commencement of such Eurodollar
                     Rate Loan or (b) the end of the Interest Period. Interest
                     charges shall be computed on the actual principal amount of
                     Advances outstanding during the month (the "Monthly
                     Advances") at a rate per annum equal to (i) with respect to
                     Revolving Advances, the applicable Revolving Interest Rate
                     and (ii) with respect to the Term Loan, the applicable Term
                     Loan Rate (as applicable, the "Contract Rate"). Whenever,
                     subsequent to the date of this Agreement, the Alternate
                     Base Rate is increased or decreased, the applicable
                     Contract Rate shall be similarly changed without notice or
                     demand of any kind by an amount equal to the amount of such
                     change in the Alternate Base Rate during the time such
                     change or changes remain in effect. The Eurodollar Rate
                     shall be adjusted with respect to Eurodollar Rate Loans
                     without notice or demand of any kind on the effective date
                     of any change in the Reserve Percentage as of such
                     effective date. Upon and after the occurrence of an Event
                     of Default, and during the continuation thereof, (i) the
                     Obligations other than Eurodollar Rate Loans shall bear
                     interest at the applicable Contract Rate for Domestic Rate
                     Loans plus two percent (2%) per annum and (ii) Eurodollar
                     Rate Loans shall bear interest at the applicable Contract
                     Rate for Eurodollar Rate Loans plus two (2%) percent per
                     annum as applicable (as applicable, the "Default Rate").

               (b)   Section 3.2 (i) shall be deleted in its entirety and
replaced as follows:

                     (i) for the ratable benefit of Lenders for issuing or
                     causing the issuance of a standby letter of credit, a fee
                     computed at a per annum rate equal to two percent (2%) on
                     the outstanding amount thereof from time to time.

                                        9

<PAGE>

               (c)   Section 3.3 shall be deleted in its entirety and replaced
as follows:

                     3.3   Fees.

                     (a)   Facility Fee. If, for any month during the Term, the
                     average daily unpaid balance of the Revolving Advances plus
                     outstanding Letters of Credit for each day of such month
                     does not equal the Maximum Revolving Advance Amount, then
                     Borrowers shall pay to Agent for the ratable benefit of
                     Lenders a fee at a rate equal to three eighths of one
                     percent (.375%) per annum on the amount by which the
                     Maximum Revolving Advance Amount exceeds such average daily
                     unpaid balance. Such fee shall be payable to Agent in
                     arrears on the last day of each month.

         6.    Section 4.3 of the Loan Agreement shall be deleted in its
entirety and replaced with the following:

                     4.3.  Disposition of Collateral. Each Borrower will
                     safeguard and protect all Collateral granted by such
                     Borrower for Agent's general account and make no
                     disposition thereof whether by sale, lease or otherwise
                     except the sale of (i) Inventory in the ordinary course of
                     business; (ii) Equipment which is obsolete or not used or
                     useful in the business of Borrowers not to exceed Two
                     Hundred Fifty Thousand Dollars ($250,000) in the aggregate
                     in any fiscal year; (iii) Equipment which is replaced by
                     Equipment of comparable or superior quality and becomes
                     subject to a Lien in favor of Agent subject only to
                     Permitted Encumbrances; or (iv) the proceeds of which are
                     remitted to Agent to be applied pursuant to Section 2.14.

         7.    Section VI of the Loan Agreement shall be amended as follows:

               (a)   Section 6.5 of the Loan Agreement shall be deleted in its
entirety and replaced as follows:

                     6.5.  Fixed Charge Coverage Ratio for Radnor on a
                     Consolidated Basis. Cause to be maintained a Fixed Charge
                     Coverage Ratio for Radnor on a Consolidated Basis to be
                     equal to or greater than 1.05 to 1.00 as at the end of each
                     fiscal quarter for the most recent four fiscal quarters
                     then ended, beginning on the date hereof and continuing
                     through fiscal quarter ending December 31, 2003, and for
                     each fiscal quarter thereafter cause to be maintained a
                     Fixed Charge Coverage Ratio for Radnor on a Consolidated
                     Basis to be equal to or greater than 1.15 to 1.00,
                     calculated based on the most recent four fiscal quarters
                     then ended.

               (b)   Section 6.6 shall be deleted in its entirety and replaced
as follows:

                     6.6.  Funded Debt to EBITDA Ratio. Cause to be maintained a
                     Funded Debt to EBITDA Ratio for Radnor on a Consolidated
                     Basis to be calculated based on the most recent four fiscal
                     quarters then ended not

                                       10

<PAGE>

                     greater than the amounts set forth below for the periods
                     set forth below:

                               Period                             Funded Debt to
                                                                  EBITDA Ratio

                     At closing and each quarter end
                     through March 31, 2004                       5.00 to 1;

                     June 30, 2004 and each quarter end
                     through December 31, 2004                    4.50 to 1;

                     March 31, 2005 and each quarter end
                     through September 30, 2005                   4.25 to 1; and

                     December 31, 2005 and each quarter end
                     thereafter                                   3.75 to 1.

         8.    Section VII of the Loan Agreement shall be amended as follows:

               (a)   The reference to "$12,000,000" contained in Section 7.6
                     shall be amended to read "$13,000,000"; and

               (b)   Section 7.8(iii) shall be deleted in its entirety and
                     replaced as follows:

                     Indebtedness due under the Senior Notes and the Second
                     Senior Notes, the related indentures and/or guaranties in
                     respect of the Senior Notes and the Second Senior Notes.

         9.    The reference to "ninety (90) days" contained in the first
sentence of Section 9.7 shall be amended to read "one hundred twenty (120)
days".

         10.   The reference to "$300,000" contained in Section 10.6 shall be
amended to read "$500,000".

         11.   Section 13.1 of the Loan Agreement shall be deleted in its
entirety and replaced as follows:

               13.1. Term. This Agreement, which shall inure to the benefit of
               and shall be binding upon the respective successors and permitted
               assigns of each Borrower, Agent and each Lender, shall become
               effective on the date hereof and shall continue in full force and
               effect until the last day of the Term unless sooner terminated as
               herein provided. Borrowers may terminate this Agreement at any
               time upon fifteen (15) days' prior written notice upon payment in
               full of the Obligations. In the event the Obligations are prepaid
               in full prior to the first anniversary of the Closing Date,
               Borrowers shall pay to Agent for the benefit of Lenders an early
               termination fee in an amount equal to 1% of the Maximum Revolving
               Advance Amount plus 1% the outstanding principal balance due
               under the Term Loan. Borrowers may prepay the Term Loan in part
               at any time or from time to time without penalty.

                                       11

<PAGE>

         12.   The following section 14.11 is hereby added to the Loan Agreement
and shall read as follows:

               14.11 Other Agents. The Documentation Agent and the Lead Arranger
               are named for recognition purposes only, and in their respective
               capacities as such shall have no powers, duties responsibilities
               or liabilities with respect to this Amendment or the Existing
               Financing Agreements, it being understood that the Documentation
               Agent and the Lead Arranger shall be entitled to all
               indemnification and reimbursement rights in favor of "Agent".
               Without limitation of the foregoing, neither the Documentation
               Agent nor the Lead Arranger shall, solely by reason of this
               Amendment or the Existing Financing Agreements, have any
               fiduciary relationship in respect of any Lender or any other
               Person.

         13.   Representations and Warranties. Each Borrower hereby:

               (a)   reaffirms all representations and warranties made to Agent
and Lenders under the Agreement and all of the other Existing Financing
Agreements and confirms that all are true and correct as of the date hereof;

               (b)   reaffirms all of the covenants contained in the Agreement
and covenants to abide thereby until all Advances, Obligations and other
liabilities of Borrowers to Agent and Lenders, of whatever nature and whenever
incurred, are satisfied and/or released by Agent and Lenders;

               (c)   represents and warrants that no Default or Event of Default
has occurred and is continuing under any of the Existing Financing Agreements;

               (d)   represents and warrants that it has the authority and legal
right to execute, deliver and carry out the terms of this Amendment, that such
actions were duly authorized by all necessary corporate action and that the
officers executing this Amendment on its behalf were similarly authorized and
empowered, and that this Amendment does not contravene any provisions of its
Articles of Incorporation and By-laws or of any contract or agreement to which
it is a party or by which any of its properties are bound; and

               (e)   represents and warrants that this Amendment and all
assignments, instruments, documents, and agreements executed and delivered in
connection herewith, are valid, binding and enforceable in accordance with their
respective terms.

         14.   Conditions Precedent/Effectiveness Conditions. This Amendment
shall be effective upon satisfaction of the conditions set forth in Section 15
below as well as completion of the following conditions precedent (all documents
to be in form and substance satisfactory to Agent and Agent's counsel):

               (a)   Agent shall have received fully paid mortgagee title
insurance policies (or binding commitments to issue title insurance policies,
marked to Agent's satisfaction to evidence

                                       12

<PAGE>

the form of such policies to be delivered with respect to each Mortgage), in
standard ALTA form, issued by a title insurance company satisfactory to Agent,
each in an amount equal to not less than the fair market value of the Mortgaged
Properties subject to the Mortgage, insuring the Mortgages create a valid Lien
on the Mortgaged Properties with no exceptions which Agent shall not have
approved in writing and no survey exceptions;

               (b)  Borrowers shall demonstrate, after giving effect to the
Advances hereunder, Undrawn Availability of at least $8,000,000;

               (c)  The receipt by Agent of each Lender's Commitment Percentage
of the Revolving Advances and the Term Loan (in an aggregate amount equal to
Fifty Million Dollars ($50,000,000)) pursuant to those certain commitments
received from the additional lenders; and

               (d)  Agent shall have received all fees which are payable to
Agent or to the Lenders as required by the Loan Agreement, this Amendment or any
fee letter entered into by Borrowers and Agent.

         In addition, failure to provide Agent, within ninety (90) days of the
date of this Amendment, executed landlord waivers and mortgagee waivers from
each landlord and/or mortgagee of Borrowers, each in form and substance
satisfactory to Agent and its counsel, shall be an Event of Default under the
Loan Agreement and Agent may waive such an Event of Default only with the
consent of Lenders holding one hundred percent (100%) of the Advances, or if no
Advances are outstanding one hundred percent (100%) of the Commitment
Percentages.

         15.   Additional Effectiveness Condition. Notwithstanding satisfaction
of the conditions set forth in Section 14 above, this Amendment shall not become
effective, and funding hereunder shall not occur, until (i) Borrowers have
successfully completed a high-yield debt offering for the issuance of
$135,000,000 of new notes on terms and conditions substantially in accordance
with the preliminary offering memorandum dated February 19, 2003; and (ii)
Borrowers have received the net proceeds from the issuance of new notes in
connection with such high-yield debt offering (such clause (i) and clause (ii),
collectively, the "Bond Refinancing"). In the event the Borrowers do not
successfully complete such high-yield debt offering, or Borrowers do not receive
the net proceeds due to Borrowers in connection with the Bond Refinancing within
twenty (20) days of the date of this Amendment, this Amendment shall be void and
of no effect."

         16.   Further Assurances and Affirmative Covenant. Each Borrower hereby
agrees to take all such actions and to execute and/or deliver to Agent and
Lenders all such documents, assignments, financing statements and other
documents, as Agent and Lenders may reasonably require from time to time, to
effectuate and implement the purposes of this Amendment.

         17.   Payment of Expenses. Borrowers shall pay or reimburse Agent and
Lenders for its reasonable attorneys' fees and expenses in connection with the
preparation, negotiation and execution of this Amendment and the documents
provided for herein or related hereto.

         18.   Reaffirmation of Loan Agreement. Except as modified by the terms
hereof, all of the terms and conditions of the Loan Agreement, as amended, and
all other of the Existing

                                       13

<PAGE>

Financing Agreements are hereby reaffirmed and shall continue in full force and
effect as therein written.

         19.   Miscellaneous.

               (a)  Third Party Rights. No rights are intended to be created
hereunder for the benefit of any third party donee, creditor, or incidental
beneficiary.

               (b)  Headings. The headings of any paragraph of this Amendment
are for convenience only and shall not be used to interpret any provision
hereof.

               (c)  Modifications. No modification hereof or any agreement
referred to herein shall be binding or enforceable unless in writing and signed
on behalf of the party against whom enforcement is sought.

               (d)  Governing Law. The terms and conditions of this Amendment
shall be governed by the laws of the Commonwealth of Pennsylvania.

               (e)  Counterparts. This Amendment may be executed in any number
of counterparts and by facsimile, each of which when so executed shall be deemed
to be an original and all of which taken together shall constitute one and the
same agreement.

                      [Signatures begin on following pages]

                                       14

<PAGE>

         IN WITNESS WHEREOF, the parties have caused this Amendment to be
executed and delivered by their duly authorized officers as of the date first
above written.

                            WINCUP HOLDINGS, INC.

                            By: /s/ R. Radcliffe Hastings
                               -------------------------------------------------
                            R. Radcliffe Hastings, Sr. Vice President, Treasurer

                            RADNOR CHEMICAL CORPORATION

                            By: /s/ R. Radcliffe Hastings
                               -------------------------------------------------
                            R. Radcliffe Hastings, Sr. Vice President, Treasurer

                            STYROCHEM U.S., LTD.
                            By: StyroChem GP, LLC, its General Partner
                            By: Radnor Chemical Corporation, its Sole Member

                            By: /s/ R. Radcliffe Hastings
                               -------------------------------------------------
                            R. Radcliffe Hastings, Sr. Vice President, Treasurer

                            RADNOR HOLDINGS CORPORATION

                            By: /s/ R. Radcliffe Hastings
                               -------------------------------------------------
                            R. Radcliffe Hastings, Sr. Vice President, Treasurer

                            RADNOR DELAWARE II, INC.

                            By: /s/ R. Radcliffe Hastings
                               -------------------------------------------------
                            R. Radcliffe Hastings, Sr. Vice President, Treasurer

                            STYROCHEM DELAWARE, INC.

                            By: /s/ R. Radcliffe Hastings
                               -------------------------------------------------
                            R. Radcliffe Hastings, Sr. Vice President, Treasurer

                             Signature Page 1 of 4

<PAGE>

                            WINCUP TEXAS, LTD.
                            By: WinCup GP, LLC, its General Partner
                             By: WinCup Holdings, Inc., its Sole Member

                            By: /s/ R. Radcliffe Hastings
                               -------------------------------------------------
                            R. Radcliffe Hastings, Sr. Vice President, Treasurer

                            STYROCHEM GP, L.L.C.
                            By: Radnor Chemical Corporation, its Sole Member

                            By: /s/ R. Radcliffe Hastings
                               -------------------------------------------------
                            R. Radcliffe Hastings, Sr. Vice President, Treasurer

                            STYROCHEM LP, L.L.C.
                            By: Radnor Chemical Corporation, its Sole Member

                            By: /s/ R. Radcliffe Hastings
                               -------------------------------------------------
                            R. Radcliffe Hastings, Sr. Vice President, Treasurer

                            WINCUP GP, L.L.C.
                            By: WinCup Holdings, Inc. its Sole Member

                            By: /s/ R. Radcliffe Hastings
                               -------------------------------------------------
                            R. Radcliffe Hastings, Sr. Vice President, Treasurer

                            WINCUP LP, L.L.C.
                            By: WinCup Holdings, Inc. its Sole Member

                            By: /s/ R. Radcliffe Hastings
                               -------------------------------------------------
                            R. Radcliffe Hastings, Sr. Vice President, Treasurer

                             Signature Page 2 of 4

<PAGE>

                                     Agents:
                                     PNC BANK, NATIONAL ASSOCIATION,
                                     as Agent

                                     By:  /s/ Rodger Rickenbrode
                                          --------------------------------------

                                     Name:  Rodger Rickenbrode
                                            ------------------------------------

                                     Title:  Senior Vice President
                                             -----------------------------------

                                     PNC BANK, NATIONAL ASSOCIATION,
                                     as Lead Arranger and Administrative Agent

                                     By:  /s/ Rodger Rickenbrode
                                          --------------------------------------

                                     Name:  Rodger Rickenbrode
                                            ------------------------------------

                                     Title:  Senior Vice President
                                             -----------------------------------

                                     FLEET CAPITAL CORPORATION,
                                     as Documentation Agent

                                     By:  /s/ Robert Anchundia
                                          --------------------------------------

                                     Lenders:
                                     PNC BANK, NATIONAL ASSOCIATION,
                                     as Lender

                                     By:  /s/ Rodger Rickenbrode
                                          --------------------------------------

                                     Name:  Rodger Rickenbrode
                                            ------------------------------------

                                     Title:  Senior Vice President
                                             -----------------------------------
                                     Commitment Percentage: 44.444%

                             Signature Page 3 of 4

<PAGE>

                                       FLEET CAPITAL CORPORATION, as Lender

                                       By:  /s/ Robert Anchundia
                                            ------------------------------------

                                       Name:  Robert Anchundia
                                              ----------------------------------

                                       Title:  Vice President
                                               ---------------------------------
                                       Commitment Percentage: 27.777%

                                       LASALLE BUSINESS CREDIT, LLC,
                                       as Lender

                                       By:  /s/ Donald A. Tomlinson
                                            ------------------------------------

                                       Name:  Donald A. Tomlinson
                                              ----------------------------------

                                       Title:  Vice President
                                               ---------------------------------
                                       Commitment Percentage: 27.777%

                             Signature Page 4 of 4

<PAGE>

                        [SCHEDULES AND EXHIBITS OMITTED]