叠氮型热塑性聚氨酯弹性体的制备及性能研究

发布时间：2018-01-03 05:16

  本文关键词：叠氮型热塑性聚氨酯弹性体的制备及性能研究　出处：《南京理工大学》2017年硕士论文　论文类型：学位论文

  更多相关文章： GAP PTMG 机械力学性能 动态力学性能 PBT 支化

【摘要】：叠氮聚醚复合固体推进剂具有高能、高燃速、低特征信号等优点,是目前推进剂发展的一个重要方向。其中叠氮缩水甘油醚(GAP)和叠氮类聚醚3,3-叠氮甲基环氧丁烷-四氢呋喃(PBT)由于能够提供较高的能量,并且具有较低的玻璃化转变温度等因而被广泛用于粘合剂的制备和研究。然而由于这类聚醚分子侧链含有刚性叠氮基团,其单体相对分子质量较大,使得分子柔顺性变差,是造成叠氮聚醚推进剂力学性能不佳的原因之一。本文一方面通过引入柔顺型良好的结晶软段与GAP形成协同作用,改善弹性体的力学性能,另外一方面通过对PBT进行支化改性,改善其工艺性能和力学性能。为了探究软段的引入对GAP基热塑性聚氨酯弹性体的影响,采用熔融预聚法制备了一系列嵌段共聚物聚氨酯弹性体试样,通过单因素实验确定最优化的工艺条件为:选择聚四氢呋喃(PTMG)作为第二软段,4,4-二苯基甲烷二异氰酸酯(MDI)作为固化剂,一缩二乙二醇(DEG)作为扩链剂,固化参数R值(NCO/OH)为1.2,DEG含量为 20%。对GAP-PTMG热塑性弹性体不同软段组分(GAP/PTMG分别为5/5,6/4,7/3,8/2,9/1)进行进一步的探究,其拉伸性能和动态力学性能实验结果表明,当GAP含量为50%时,其拉伸强度达到18.97MPa,延伸率为770%,Tg为-18.56℃,即具有良好的力学性能;其蠕变性能和应力松弛实验结果表明GAP-PTMG热塑性弹性体具有一定的粘弹塑性特性,并且随着GAP含量增加,蠕变应变量增加,更易产生应力松弛现象;通过热力学分析表明其具有良好的热稳定性。为改善PBT的工艺性能,本文以PBT为起始聚醚,三官能度的支化单元为引发剂,通过亲核加成反应合成一种具有支化结构的PBT(B-PBT),然后通过一步法制备得到B-PBT热塑性弹性体。通过结构分析表明B-PBT为具有支化结构的叠氮型聚醚;通过粘度测试表明B-PBT的粘度明显低于PBT;通过力学性能测试表明制备的B-PBT热塑性弹性体拉伸强度达到5.29 MPa,延伸率达到516%。
[Abstract]:Azide polyether composite solid propellant has the advantages of high energy, high burning rate, low characteristic signal and so on. It is an important direction of propellant development at present, including azide glycidyl ether (GAPP) and azido polyether 3 (azido polyether 3). 3-azidomethyl epoxy-butane-tetrahydrofuran (PBT) can provide higher energy. Because of its low glass transition temperature and so on, it is widely used in the preparation and study of adhesives. However, due to the existence of rigid azide groups in the side chain of this kind of polyether, the relative molecular weight of the monomers is larger. One of the reasons for the poor mechanical properties of azido polyether propellants is the deterioration of molecular flexibility. On the one hand, the flexible crystalline soft segment is introduced to form a synergistic effect with GAP. On the other hand, the mechanical properties and technological properties of PBT were improved by branching modification. In order to explore the effect of soft segment on GAP based thermoplastic polyurethane elastomer. A series of block copolymer polyurethane elastomer samples were prepared by melt prepolymerization. The optimum technological conditions were determined by single factor experiment: PTMGG was selected as the second soft segment. 4-diphenylmethane diisocyanate (MDI) was used as curing agent and diethylene glycol (DEG) as chain extender. The curing parameter R value of NCO / OH was 1.2. The DEG content is 20. For GAP-PTMG thermoplastic elastomers, the GAP-PTMG / PTMG is 5 / 5 / 6 / 4 / 4 / 7 / 3 / 8 / 2, respectively. 9 / 1). The results of tensile and dynamic mechanical properties experiments show that when the content of GAP is 50, the tensile strength is 18.97 MPA and the elongation is 770%. TG is -18.56 鈩，

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