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

Polyurethane elastomers (PUE) had many excellent properties. It was a class of synthetic polymer materials. It had so many outstanδing properties that many other materials could not come up to. For example, high-abrasion resistance, tear resistance, excellent solvent resiatance and so on. But there was an important flaw when it was used. That was the weak thermal resistance which made it could only be used at low temperature. Therefor its use was limited. In order to enlarge its applying scope, the thermal resistance must be improved. In this article, the molecular structure of PUE had been changed to improve its thermal resistance. Concrete methods was listed below.First of all, polyurethane elastomer was prepared by prepolymer process. And in the process, the mixed chain extender of TMP/MOCA was used to increase the crosslink density of the PUE molecule. The results showed that the mechanical property retention ration was raised at 100℃, tensile strength was raised from 43.1% to 54.7%,tear strength was raised from 34.5% to 47.9%. The temperature of the largest weight loss was raised from 369.8℃to 376.7℃. The solvent resistance were improved.Next, in the synthesis of the prepolymer, the organosilicon structure was introduced to the PUE molecule. The results showed that modified by organosilicon, the thermal resistance of PUE was improved,and the mechanical property retention ration was raised at 100℃, tensile strength was raised from 43.1% to 50.6%,tear strength was raised from 34.5% to 50.2%. The temperature of the largest weight loss was raised from 369.8℃to 375.4℃. Moreover, the highest tanδwas reduced to 0.4 ,and the tanδof the modified PUE is smaller than unmodified PUE under the same circumstances at the same temperature. The solvent resistance was also improved.Finally, as tri(2-hydroxyethyl) isocyanurate(THEIC) had the radical of–OH, THEIC could be added in the chain extender of TMP, and both THEIC and TMP could react with prepolymer. In this method, the structure of isocyanurate(IS) in THEIC has been introduced to the main chain of PUE. The results showed that, the thermal resistance of PUE was improved by introducing IS to the main chain of PU and the mechanical property retention ration was raised, tensile strength was raised from 45.7% to 51.9%,tear strength was raised from 58.1% to63.3%. At the same temperature. Compared with unmodified PUE, The highest tanδwas reduced from 0.75 to 0.55. The solvent resistance was also improved.