Diamine-Crosslinking of Poly(γ-glutamic acid) having 5-Membered Cyclic Dithiocarbonate Structures and its Application to Functional Adhesives

Abstract

Poly(γ-glutamic acid)s (DTC－γPGAs) having 5-Membered cyclic dithiocarbonate structures were synthesized, and their crosslinking along with adhesion property of the obtained materials were examined. DTC－γPGAs were prepared by addition of 5-hydroxymethyl-1,3-oxathiorane-2-thione (DTC－OH) to a dimethyl sulfoxide (DMSO) solution of γPGA in the presence of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide. Crosslinking of DTC－γPGAs was conducted by addition of 4,7,10-trioxa-1,13-tridecanediamine (TODA) as a crosslinker to an ethanol suspension leading gel formation.The polymer gels produced were cross-linked with thiourethane-linkage. Adhesion strengths were measured by coating the gels between two pieces of pig skin strip and bind together. Examination with varying TODA amount, DTC modification ratio, binding time revealed that DTC－γPGA (34/66) with 0.25 equivalent of TODA showed high T-type peering adhesion strength of 800N/m after 24 h binding.