Preparation, Properties and Morphology of Polyurethane/Tung Oil-based bi-dihydrogen-maleimide Interpenetrating Polymer Network

Abstract

PU has many good and practical properties but its heat resistance is not so satisfying that PU is not suitable to be used in some high temperature and high humid occasions. To improve PU’s heat resistance, Tung oil-based bi-dihydrogen-maleimide, TOBBDHMI, which starts from a Chinese renewable resource Tung oil, has been introduced into PU to form PU/TOBBDHMI interpenetrating polymer network through in-situ polymerization. Mechanical properties, thermal performances and morphology were compared between ordinary PU and PU/TOBBDHMI IPN. Experimental results show that along with the weight content of TOBBDHMI in the IPNs increases, hardness and tensile strength of PU/TOBBDHMI IPNs increases while the elongation at break decreases. The heat resistance of PU has improved a lot since the IPN forms: the initial decomposition temperature has improved from 275 °C (PU) to 320 °C (IPN). Thermal and morphology analysis indicated that the IPN has better compatibility than ordinary PU. Fracture SEM photograph shows that the IPN proceeds craze fracture mechanism in the tensile fracture.