基于直接酯化法制备PBST共聚酯及其结构性能研究

发布时间：2018-03-09 02:25

本文选题：PBST共聚酯　切入点：直接酯化　出处：《东华大学》2010年硕士论文　论文类型：学位论文

【摘要】： 作为经济发展的前导之一,材料的开发利用在现代文明中起着举足轻重的作用。20世纪初出现的合成高分子材料的发展态势尤为突出。以纺织纤维工业为例,至本世纪初,世界纤维总需求量的一半以上是合成纤维。但合成高分子材料的发展遇到了能源、经济和环境等问题。生物可降解高分子材料越来越引起人们的重视。脂肪族/芳香族共聚物结合了脂肪族聚酯的生物可降解性能和芳香族聚酯优良的机械性能已成为可降解材料中的研究热点,聚丁二酸丁二醇-共-对苯二甲酸丁二醇酯(PBST)就是其中之一。目前,国内外有关PBST共聚酯的研究报道,其生产方式主要以酯交换熔融缩聚的方法为主。在我们前面的研究中,通过酯交换法合成PBST共聚酯,并分别研究了它的结构、热学性能、结晶性能和酶降解性能等。但酯交换法制备PBST共聚酯的原料、能耗等成本较大。相比较而言,直接酯化缩聚法制备PBST共聚酯的成本较低,且反应生成的小分子是水,环境效益好,生产流程短、投资少,生产效率高,且二元醇用量较酯交换法少。基于此,本文以对苯二甲酸、丁二酸和1,4-丁二醇为单体原料,采用直接酯化缩合聚合法,合成生物降解性脂肪族/芳香族共聚酯聚丁二酸丁二醇-共-对苯二甲酸丁二醇酯(PBST),研究催化剂、助催化剂和稳定剂等对合成PBST共聚酯工艺的影响,并对合成共聚酯的结构性能进行研究。首先,以丁二酸、对苯二甲酸和1,4-丁二醇为原料,以四异丙氧基钛为催化剂合成PBST-70共聚酯,探讨合成工艺和合成现象。氢谱核磁共振(~1H NMR)测试表明,共聚物结构中芳香族BT链锻含量约为70%,与投料比例相近;凝胶渗透色谱仪(GPC)测试表明,所合成的PBST共聚酯重均分子量分布在8.86～10.03万;熔融指数(MI)测试结果表明,最有效的催化剂用量为二元酸的1/3000mol;使用助催化剂,缩短合成反应时间,提高反应效率,助催化剂的最佳用量为二元酸的1/5000mol;使用稳定剂,不仅提高了反应体系的热稳定性,还使共聚酯的白度提高了4%。其次,利用差示扫描量热仪(DSC)、热重分析仪(TGA)研究了PBST共聚酯的热学性能,结果表明共聚物有较好的热性能,熔融温度T_m、热分解温度T_d别可达178.37℃、389.1℃,并由此计算得结晶度最高可达25.7%;共聚酯的拉伸性能研究结果表明,助催化剂的使用降低了高聚物的热稳定性,同时使用稳定剂,可提高PBST共聚酯的断裂强力和断裂伸长;等温结晶研究表明,随着结晶温度的提高,聚合物链段结晶变慢,大分子链重新排列时间越长,排列规整性越高,重结晶形成的结晶度越高,聚合物的熔点相应增加;Avrami方程和偏光显微镜(POM)研究表明,PBST共聚酯结晶为异相成核,以球晶形式三维生长;不同温度等温结晶后,共聚酯膜的断裂伸长先升高后降低,当结晶温度为150℃时,断裂伸长达最大值91mm。
[Abstract]:As one of the leading economic development, development and utilization of materials in the modern civilization development plays a decisive role appeared in synthetic polymer materials.20 century is particularly prominent. In the textile fiber industry as an example, to the beginning of this century, more than half of the world total fiber demand is synthetic fiber. But the development of synthetic polymeric materials in energy, economy and environment. The problems of biodegradable polymer materials have attracted more and more attention. The aliphatic / aromatic copolymer with the mechanical properties of the biodegradable properties of aliphatic polyester and aromatic polyester excellent has become hot research in biodegradable material, poly butylene succinate co butylene terephthalate (PBST) is one of them.
At present, the domestic and foreign research reports of PBST copolyester, the main method of the mode of production mainly in the transesterification of melt polycondensation. In our previous studies, through transesterification synthesis of PBST copolyesters were studied, and its structure, thermal properties, crystallization properties and enzymatic degradation properties. But the ester exchange preparation of PBST polyester raw material method, energy consumption cost greatly. In comparison, the direct esterification polycondensation preparation of PBST copolyester with low cost, small molecule and the reaction is water, good environmental benefits, short production process, less investment, high production efficiency, and the amount of a diol ester exchange method.
Based on this, this paper takes terephthalic acid, succinic acid and 1,4- butanediol as raw material monomer by direct esterification condensation polymerization, synthesis of biodegradable aliphatic aromatic copolyester poly butylene succinate co butylene terephthalate (PBST), on the catalyst, cocatalyst and stabilizer effect on Synthesis of PBST copolyester in the process, and to study the synthesis structure and properties of polyester.
First of all, to succinic acid, terephthalic acid and 1,4- butanediol as raw material, with four titanium isopropoxide as catalysts to synthesize PBST-70 copolyester, investigate the synthesis and synthesis of hydrogen phenomenon. Nuclear magnetic resonance spectroscopy (~1H NMR) test showed that the aromatic BT chain forging was about 70% in copolymer structure, similar to the proportion of the material; gel permeation chromatography (GPC) test showed that the synthesized PBST polyester molecular weight distribution in 8.86 ~ 100 thousand and 300; melt index (MI) test results show that the catalyst is the most effective binary 1/3000mol; using the cocatalyst, shorten the reaction time, improve the reaction efficiency, the optimum amount of catalyst for the use of 1/5000mol stabilizer, dibasic acid; not only improves the thermal stability of the reaction system, the whiteness of polyester were increased by 4%.
Secondly, using differential scanning calorimetry (DSC), thermogravimetric analyzer (TGA) on the thermal properties of PBST copolyester, the results showed that the copolymers have good thermal properties, melting temperature of T_m, the thermal decomposition temperature of T_d to 178.37 degrees, 389.1 degrees, and then calculated the crystallinity of up to 25.7%; the results were showed that the tensile properties of polyester, the use of the catalyst decreased the thermal stability of polymers, while the use of stabilizers, PBST copolyester can improve the fracture strength and elongation; isothermal crystallization study showed that with the increase of crystallization temperature, crystallization of polymer chain segment slow molecular chain rearrangement of the longer arrangement the regularity of the higher recrystallization formed the higher crystallinity and melting point of the polymer increased; Avrami equation and polarizing microscope (POM) study showed that PBST copolyester crystallization for heterogeneous nucleation to form three-dimensional spherulite growth at different temperatures; After isothermal crystallization, the fracture elongation of the copolyester membrane first increases and then decreases. When the crystallization temperature is 150, the fracture elongation reaches the maximum value of 91mm.

【学位授予单位】：东华大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：TQ323.41

【相似文献】