Water resistance of soybean protein plastics modified by plasticizing and denaturation

Formamine,glycerol–formamine complex,urea,or SDS and soy proteins were mixed at different ratios and hot press molded for making soy protein plastics.Water absorption and R value of the plastics were investigated by using an Instron testing system and an electric heating air–blowing drier.The results showed that 2 h water absorption,24 h water absorption of formamine,glycerol– formamine complex,urea or modified plastics decreased with the content of the polymers increasing,but R values of the plastics increased,indicating improvement of water resistance of the plastics.However,2 h and 24 h water absorption of SDS modified plastics decreased,and R values of the plastics increased,indicating water resistance of the plastics decreasing.