热塑性弹性体在复合改性双基推进剂中的应用

Influence of thermoplastic polyurethane on mechanical properties of modified double base propellants

关键词:  热塑性树脂  力学性能  改性双基推进剂

Key words:  Thermoplastic resin  Mechanical performance  Modified double base propellant

摘要:

采用FTIR、动态热机械分析和单轴拉伸试验方法对所合成的P(E-CO-T)-IPDI-BDO热塑性弹性体(TPU)的性能进行了表征,并对P(E-CO-T)-IPDI-BDO预聚物在复合改性双基推进剂及其粘合剂体系中的应用进行了初步的探讨。结果显示,当-NCO与-OH的当量数之比R取1.2时,P(E-CO-T)-IPDI-BDO胶片的力学性能较好,随着硬段含量的增加,拉伸强度逐步增加,最大能达到11.6 MPa,断裂延伸率呈现逐步递减的趋势。P(E-CO-T)-IPDI-BDO预聚体中-NCO与硝化纤维素NC上的-OH的化学交联使最大拉伸强度从2.07 MPa提高到2.95 MPa,断裂延伸率从110.5%提高到224.0%。加入P(E-CO-T)-IPDI-BDO预聚物的复合改性双基推进剂的动态力学性能显示,由损耗峰tanδ的高温峰确定推进剂的玻璃化转化温度Tg为27.0℃,低温峰说明在低于-37.2℃下推进剂仍能承受一定的动态载荷。

Abstract:

A series of thermoplastic polyurethane(TPU) based on tetrahydrofuran-ethylene oxide copolyether [P(E-CO-T)],isophorone diisocyanate(IPDI) and 1,4-butanediol(BDO) were synthesized and investigated by using FTIR,dyanmic mechanical analysis and tension dynamic mechanical technology,and the application of P(E-CO-T)-IPDI-BDO prepolymer in crosslinked modified double base propellant and its binder system was also discussed.The results showed that when R was 1.2,the mechanical properties of TPU were better and with the increase of hard segment content,the maximam tension strength σm of TPU increased to 11.6 MPa,while break elongation εb decreased gradually.The chemical crosslinking of-NCO of P(E-CO-T)-IPDI-BDO prepolymer with-OH of Nitrocellulose had improved σm to 2.95 MPa from 2.07 MPa and εb to 224.0% from 110.5% compared with uncrosslinked propellant binder system.The dynamic mechanical analysis results indicated that glass-transition temperature Tg of crosslinked modified double base propellant,which defined from tanδ higher peak temperature,was 27.0 ℃ and its lower peak of tan δ illustrated that the propellant was able to burden dynamic load in a certain extent under-37.2 ℃.