Synthesis Of Thermal Resistance Of PUE And Study On Its Structure And Properties

The thermal properties of polyurethane elastomer (PUE) was studied in thispaper. In order to improve its thermal stability and broaden the application areas ofthe PUE, three different methods for chemical modification were used in this paper.Besides the thermal properties, mechanical properties, dynamic performance and thesolvent resistance properties of PUE have also been studied.Firstly, synthetic methods on Double-prepolymerization polyurethane elastomerwere briefly introduced in this aticle. Isocyanate-terminated prepolymer was set asthe A component, hydroxyl-terminated prepolymer was set as the B, differentamounts of TMP were introduced into the B component, they were mixed together toprepare PUE. A relatively better ratio was found by the experimental exploration: Acomponent NCO%=5%, B component OH%=2%,5%TMP were added to preparethe sample with the best mechanical properties(tensile strength was up to16.3MPa).In addition, the results of DSC, TG tests showed that the temperature gradientmethod used to prepare vulcanized elastomer greatly improved the heat resistance,and at80℃and100℃temperature of circumstances, the retention rate ofmechanical performance was maximum, the maximum weight loss peak of the DTGtests appeared at410.9℃,9.6℃more than in conventional curing specimens. Thedynamic performance and the solvent resistance were also improved.Secondly, the prepolymer process methods were used to prepare PUE. And inthe process, the mixed chain extenders of THEIC/TIPA were used to increase thecrosslinking density of the PUE macromolecule. When the molar ratio of THEICand TIPA was2:3, tensile strength reached the critical value to27.6MPa; and at80℃and100℃temperature of circumstances, the retention rate of mechanicalperformance was maximum; The thermal stability of the PUE was improved with theintroduction of the isocyanurate ring (IS ring), There appeares a sharpthermo-gravimetric peak in395.8℃of the modified PUE sample, which is increasedby24.4℃compared to the temperature corresponding to the blank samples. The loss factor tan δ reaches maximum value of0.50at-33℃. The introduction of the ring ISimproved the solvent resistant performance of PUE.Finally, the prepolymer process methods were also used to prepare PUE in thispart, the mixed chain extenders of MOCA/THEIC were used to increase thecrosslinking density of the PUE macromolecule. When the molar ratio of MOCA andTHEIC was4:1, the retention rate of mechanical performance was maximum at80℃and100℃temperature of circumstances. The introduction of the ring IS improved thethermal stability of PUE, the modified PUE has a wider temperature range of thermalstability.The sharp thermo-gravimetric peak appears at426.4℃,which is18.5℃higher than that of the blank samples.And the degree of the thermo-gravimetricreduced. With the introduction of the ring IS the dynamic performance and the solventresistance were also improved.