This prepolymer was analyzed and the PTMO was found to be little extended with MDI units and had the composition of MDI-[PTMO.
The ABA tri-block copolymers were prepared by reacting a MDI-end-capped PTMO prepolymers with the mono functional amine-diamide segment 6T6m (Fig.
At high strains (>250%), the fracture stress increased significantly due to the strain-hardening of the PTMO soft segments (Fig.
The elastic properties of the tri-block copolymer were determined by CS experiments performed at 40[degrees]C, well above the melting temperature of PTMO (Table 3).
Two kinds of PTMO (Shin-Etsu, Taiwan) with average molecular weights of 1000 and 2000 (g/mol) were used.
Polymerization of IPDI with PTMO or siloxane diols, and copolymerization of IPDI, PTMO, and siloxanes in a bulk system were performed in a differential scanning calorimeter (DSC2010, TA instrument).
By recording the exothermic heat in DSC, the reactivities of PTMO and siloxanes during the reaction with IPDI in bulk could be studied.
The incompatibility, steric hinderance, and chain length of polydiols were the factors influencing the reactivities of PTMO and siloxane diols reacting with IPDI.
It implied that the reaction between IPDI and PTMO was efficiently catalyzed by SnDBL.