HYDRATION INDUCED CROSSLINKING IN BIOHYBRID THERMOPLASTIC PROTEIN FOAMS

摘要

In this paper we show that it is possible to tailor water absorption, the migration of plasticizer as well as the mechanical properties of thermoplastic zein (TPZ) foams by controlling the hydrolysis-condensation induced crosslinking of a bio-hybrid material using a sol-gel approach. The hybrid structure consisting of siloxane domains covalently bounded to the zein macromolecules was achieved through reactive mixing involving the amine groups of zein and the epoxy groups present in 3-glycidoxypropyltrimethoxysilane (GOTMS). Crosslinking reactions were then obtained through the hydrolysis and condensation of silane alkoxides moieties. Cellular structures were obtained by using environmental friendly blowing agents with the batch foaming technique. Different morphologies were obtained by controlling the gas composition (CO2 , N2 and N2/CO mixture) as well as the foaming conditions.