| Hydroxyl-terminated polybutadiene (HTPB) is a kind of telechelic polyols pre-polymer,it is an important species in liquid rubber, it has good transparency, viscosity of low viscosity,oil resistant, aging resistant, good low temperature performance and machining performance,it can be with diisocyanate (toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), etc.)on crosslinking reaction and be made into all kinds of polyurethane materials, which arewidely used in elastomer coatings, adhesives, and many other fields. But because of its curingtime was longer and curing temperature is higher, and its mechanical properties when not addfiller was poorer. Therefore, more and more people at home and abroad get rapidly attentionto the HTPB room temperature.The paper is based on HTPB as raw material, by two-step process and one-step synthesisof HTPB elastomer, respectively, by comparing the two methods of elastomer mechanicalproperties, various indexes of two-step synthetic elastomer mechanical properties of waspoorer, so we focused on one-step synthesis of HTPB elastomer and examines its mechanicalproperties, rheological properties and heat curing given off by curing reaction, and study theinfluence of thermal curing by studying the temperatures, curing agents, chain extenders,curing parameters and catalysts on the HTPB elastomer mechanical properties, rheologicalproperties.In this paper, the main research contents and conclusions are as follows:(1) Under the condition of vacuum, we watered for raw materials. By one-stepsynthetic of HTPB elastomer mechanical properties examination, when curingparameter(NCO/OH) R=1.2, curing agent was TDI, chain extender was1.4-butylglycol(BDO), elastomer mechanical properties can be better, with968.8%elongation at break,with1.55MPA tensile strength and with42hardness, including TEPB was the most suitable for as a catalyst at room temperature.(2) The curing parameters, chain extender, curing agent on elastomer flow and theinfluence of flowing properties were analyzed,and the result showed that flow property wasbad and not suitable for as a matching system and2-amine system of chain extender doesn’tfit as chain extender, and MDI are not suitable for as a curing agent by analyzed therheological properties of casting type elastomer HTPB adhesive.When vetting catalyst factors,we found that only TEPB logarithm can detect its viscosity, but when T-9and T-12as acatalyst, because the catalytic activity is too big, the reaction was dramatic, its apparentviscosity was too big, its viscosity logarithmic growth curve can not be measured.we foundthat when R=1.2, curing agent was TDI, chain extender was BDO, adhesive had good flowproperty, initial flow index n=0.98. This system can be used as pouring optimal proportion.(3) The dates of the curing time, curing parameters, a curing agent, DSC curve of thechain extender and the catalyst was analyzed by DSC of casting HTPB cured elastomericadhesive. Based on studying the influence of curing time, curing agents, chain extenders,curing parameters and catalysts, when R=1.2, curing agent was TDI, chain extender wasBDO, catalyst was TEPB, system heat of solidification is25.54kJ mol-1, and its curingreaches the most sharp peak, so curing reaction rate was the highest.To sum up, when the formula for HTPB-TDI-BDO-TEPB, the best relative value ofmechanical properties, rheological properties and thermal properties can be obtained.Theapparent activation energy was46.24kJ mol-1by DSC of casting HTPB cured elastomericadhesive. |
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