Influence of diisocyanate types on properties of chain-extended poly(3,3-bis(azidomethyl)oxetane)

Various chain-extended poly(3,3-bis(azidomethyl)oxetane) (CE-PBAMO) polymers were prepared by using different diisocyanates. Thermal analysis, mechanical property, and interfacial and rheological characteristics were tested to investigate the influence of diisocyanates on the properties of CE-PBAMO. T_g of CE-PBAMO varies with the type of diisocyanate, which is probably relative to the flexibility of structure. However, all the isocyanates did not differ very much in the thermal decomposition. Mechanical test results showed that the CE-PBAMO extended by isophorone diisocyanate (IPDI) could achieve better tensile strength and elongation at break. W_a between CE-PBAMO and solid ingredients increased significantly compared to PBAMO due to the formation of urethane polar groups. CE-PBAMO contains rigid segments that reduce the chain mobility and increase the relaxation time, friction, and heat loss, then exhibit higher G′ and G″.