Abstract

In this study, a new type of star multifunctional polyisoprene liquid rubber 4-arm star hydroxyl terminated polyisoprene (4HTPI-Si) that can be used for rocket solid propellant matrix was designed and synthesized by anionic polymerization method. It was characterized by Fourier Transform Infrared Spectroscopy (FT-IR), 1H Nuclear Magnetic Resonance Spectroscopy (1H-NMR) and Gel Permeation Chromatography (GPC), and the mechanical properties of the cured product obtained by blending with hydroxyl-terminated polybutadiene (HTPB) liquid rubber, a traditional solid propellant matrix, were studied. The results show that the aliphatic alkyl lithium initiator with silane-protected hydroxyl group and silicon tetrachloride coupling agent can polymerize isoprene monomers to obtain 4HTPI-Si with narrow molecular weight distribution (Mw/Mn = 1.14). The molecular weight of the polymer can be precisely designed, the average functionality is very close to 4. In the polymer synthesized in nonpolar solvent, 1,4- structure accounts for the majority. By proper blending, the tensile strength and elongation at break of the cured product of commercial HTPB can be improved by 281% and 66.7%.

摘要

本研究采用阴离子聚合法设计并合成了一种可用于火箭固体推进剂基质的新型星形多功能聚异戊二烯液体橡胶四臂星形羟基封端聚异戊二烯（4HTPI-Si）。通过傅里叶变换红外光谱（FT-IR）、1H核磁共振光谱（1H-NMR）和凝胶渗透色谱（GPC）表征，与端羟基聚丁二烯（HTPB）共混所得固化物的力学性能) 液体橡胶，一种传统的固体推进剂基质，进行了研究。结果表明，具有硅烷保护羟基的脂肪族烷基锂引发剂和四氯化硅偶联剂可以使异戊二烯单体聚合得到分子量分布窄（Mw/Mn=1.14）的4HTPI-Si。聚合物的分子量可以精确设计，平均官能度非常接近4。在非极性溶剂中合成的聚合物中，1,4-结构占大部分。通过适当掺混，市售HTPB固化产品的拉伸强度和断裂伸长率可分别提高281%和66.7%。