Effect of Hydrogen Bonding Interaction on the Properties of Caprolactam-Modified Casein/Waterborne Polyurenthane Composite

Caprolactam modified casein(CA-CPL) was prepared by using casein and caprolactam firstly. Caprolactam modified casein/waterborne polyurethane composite (CA-CPL/WPU) was prepared from CA-CPL and WPU. Effect of compounding conditions, such as the WPU dosage, compounding temperature and compounding time on CA-CPL/WPU performance were investigated. The results indicated that: CA-CPL/WPU achieved superior comprehensive performance when the WPU dosage was 50%, the compounding temperature and the compounding time was 80°Cand 2 h respectively. Viscosity of CA-CPL/WPU decreased firstly with the increasing amount of WPU When the WPU dosage was lower than 30%, and then increased gradually when the WPU dosage was higher than 30%. The more the dosage of WPU used in the reaction, the less dilution stability CA-CPL/WPU had. Acidic resistance, alkali resistance and electrolyte resistance of CA-CPL/WPU seemed to be invariable after WPU was introduced , but water resistance and softness of the film were improved. FT-IR and DLS results indicated that via the compounding process, certain hydrogen bonding interaction in CA-CPL/WPU took place and the obtained CA-CPL/WPU had a small Z-average size and polydispersity.