Claims
- 1. A crosslinked poly(amino acid) having the stoichiometric formula:
- �A!.sub.x �B!.sub.y,
- wherein A represents repeat units of backbone polymer structure �1! and B represents crosslinking units of structures �2! or �3! randomly distributed among the units of polymer structure �1! through ester linkage formation with a carboxylate group of radical R, ##STR6## wherein x represents weight percent of A units and y represents weight percent of B units, based on weight of combined A and B units; wherein x is from 80 to 99.9 weight percent and y is from 0.1 to 20 weight percent; m is 0, 1 or 2; n is from 20 to 20,000; R is a radical selected from the group consisting of one or more of --C(.dbd.O)OM, --CH.sub.2 C(.dbd.O)OM and --CH.sub.2 CH.sub.2 C(.dbd.O)OM, and M is selected from the group consisting of one or more of H, alkali metal ion and alkaline earth metal ion; X is O, S or N; R.sup.1 is a residue of a di-, tri- or tetrafunctional group selected from (C.sub.1-C.sub.4)alkylene, aryl, arylalkyl and methylene ether of a (C.sub.6 -C.sub.5)polyphenol, (C.sub.2 -C.sub.6)alkanepolyol or poly(alkylene glycol); each R.sup.2 is H when X is O or S and each R.sup.2 is independently H or (C.sub.1 -C.sub.3)alkyl when X is N; R.sup.3 is a residue of a di-, tri- or tetrapropionate ester of a (C.sub.2 -C.sub.6)alkanepolyol; a is 0 or 1; and b is 1, 2 or 3.
- 2. The crosslinked poly(amino acid) of claim 1 wherein R.sup.1 is selected from the group consisting of one or more of bis-(C.sub.1 -C.sub.4)alkylene, 1,4-phenyl, 1,3-phenyl, di(methylene) ether of ethylene glycol, di(methylene) ether of hydroquinone and di(methylene) ether of 4,4'-isopropylidenediphenol.
- 3. The crosslinked poly(amino acid) of claim 1 wherein n is from 200 to 5,000.
- 4. The crosslinked poly(amino acid) of claim 1 wherein y is from 1 to 3 weight percent.
- 5. A process for preparing crosslinked poly(amino acids) comprising:
- (a) contacting an aqueous solution of poly(aminoacid) with 0.1 to 20 percent by weight of crosslinker, based on weight of poly(amino acid), in a reaction mixture at a pH from 3 to 7, wherein the poly(amino acid) is selected from the group consisting of one or more of poly(aspartic acid) and poly(glutamic acid) and the crosslinker is selected from the group consisting of one or more crosslinkers of formula �4! and �5!, ##STR7## where X.sup.1 =O, S or NR.sup.2, R.sup.1 =a residue of a di-, tri- or tetrafunctional group selected from (C.sub.1 -C.sub.4)alkylene, aryl, arylalkyl and methylene ether of a (C.sub.6 -C.sub.15)polyphenol, (C.sub.2 -C.sub.6)alkanepolyol or poly(alkylene glycol);
- R.sup.2 =H or (C.sub.1 -C.sub.3)alkyl,
- R.sup.3 =a residue of a di-, tri- or tetrapropionate ester of a (C.sub.2 -C.sub.6)alkanepolyol,
- a=0 or 1, and
- b=1, 2 or 3,
- (b) removing water from the reaction mixture,
- (c) subjecting the reaction mixture to a heat treatment, and
- (d) recovering the crosslinked poly(amino acid) as a solid.
- 6. The process according to claim 5 wherein the pH is from 5 to 6.5.
- 7. The process according to claim 5 wherein the crosslinker is selected from the group consisting of one or more of ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, 1,2,3,4-diepoxybutane, 4,4'-isopropylidene-diphenol diglycidyl ether, hydroquinone diglycidyl ether, pentaerythritol-tris�.beta.-(N-aziridinyl)propionate! and trimethylolpropane-tris�.beta.-(N-aziridinyl)-propionate!.
- 8. The process according to claim 5 wherein water is removed from the reaction mixture by freeze-drying followed by a heat treatment conducted at 100 to 200.degree. C. for 15 minutes to 90 minutes before recovery of the crosslinked poly(amino acid).
- 9. The process according to claim 5 wherein steps (b) and (c) are combined into one step by heating the reaction mixture in an oven at 120 to 220.degree. C. for 30 minutes to 2 hours before recovery of the crosslinked poly(amino acid).
- 10. The process according to claim 5 wherein the weight percent of crosslinker is from 0.5 to 5 percent, based on weight of poly(amino acid).
- 11. The process according to claim 5 wherein the weight percent of crosslinker is from 1 to 3 percent, based on weight of poly(amino acid).
Parent Case Info
This application claims the benefit of U.S. Provisional Application Ser. No. 60/047,916 filed May 29, 1997.
US Referenced Citations (7)
Foreign Referenced Citations (2)
Number |
Date |
Country |
683177 |
Nov 1995 |
EPX |
802215 A1 |
Oct 1997 |
EPX |