生物降解聚合物论文：PBS-PA6IcoT交换反应及其产物研究

1、 生物降解聚合物论文：PBS-PA6IcoT交换反应及其产物研究【中文摘要】可降解高分子材料近年来备受关注,但大部分聚酯可降解高分子材料存在热性能、力学性能较差的缺点。而聚酰胺则由于含有酰胺键(-CONH-),以及分子链间氢键的存在,具有较好的热性能和力学性能,但聚酰胺难以降解。综合上述两类聚合物的特点,本文拟以高分子量的脂肪族聚酯和半芳香族聚酰胺为原料,经由酯-酰胺交换反应制备高分子量的聚酯酰胺。首先,聚丁二酸丁二醇酯(PBS)和无定形尼龙聚间(对)苯二甲酰己二胺(PA6IcoT)在卧式反应釜中进行熔融反应共混,利用溶解度实验、FT-IR和13C-NMR对交换反应的机理和生成的共聚物的结构进

2、行了表征,并利用扫描电镜研究了交换反应对共混物相形态的影响。结果表明,以对甲苯磺酸(TsOH)为催化剂时,PBS和PA6IcoT之间可发生交换反应。随着反应程度的增大,共聚物的无规度增大,分子量分布变宽。交换反应生成的共聚物可起到相容剂的作用,改善了共混物中两相的相容性,分散相颗粒尺寸明显变小。其次,系统研究了PBS和PA6IcoT熔融共混物的等温和非等温结晶动力学,晶体形态和晶体结构。结果表明,PA6IcoT抑制PBS的结晶,导致结晶活化能增大,结晶速率和结晶度减小。交换反应破坏了产物链段的规整性,更加剧了这一效应。随着反应程度增大,共混物结晶形态发生较大变化,球晶尺寸逐渐减小,界面变得越来

3、越模糊；晶体结构变化较小,但是反应共混物的衍射峰位置出现漂移。最后,探讨了共混物的化学结构和凝聚态结构对共混物热性能、力学性能和降解性能的影响。研究结果表明,由于体系相容性得到改善,两者的玻璃化温度逐渐向中间靠拢。交换反应生成的共聚物链段中含有刚性基团,使得共混物的热分解性能显著提高。PBS和PA6IcoT物理共混时,由于相容性差力学性能下降。随着交换反应程度的增加,PA6IcoT的链段逐渐进入PBS的链段中,产物的拉伸强度、拉伸模量和冲击强度均高于PBS。另外,随反应程度提高,共混物结晶度减小,无规度增加,有利于其生物降解。这样在提高热性能和力学性能的同时,可以保持其可生物降解性。【英文摘要

4、】In recent years, many researchers are focusing on the environmentally friendly materials, especially on the biodegradable polymers. Most of the biodegradable polymers are polyesters, which have poor thermal properties and mechanical properties. Therefore, their practical applications are limited. O

5、n the other hand, the polyamide chains contain amide bond (-CONH-). Because of the existence of hydrogen bonds between molecular chains, they have good thermal and mechanical properties. However, they are not biodegradable. To combine the advantage of two polymers, high molecular weight poly(ester a

6、mide)s are prepared by ester-amide exchange reaction between aliphatic polyester and semi-aromatic polyamide.Firstly, amorphous nylon PA6IcoT and poly(butylene succinate) (PBS) are blended in the horizontal reactor under melting conditions. The mechanism of exchange reaction and structure of copolym

7、ers are analyzed by solubility experiment, FT-IR and 13C-NMR. Scanning electron microscope (SEM) is used to analyze the influence of exchange reaction on phase morphology. The results show that ester-amide exchange reaction between PBS and PA6IcoT can occur with paratoluenesulfonic acid as the catal

8、yst. With the increase of reaction extent, the randomness of copolymers is increased and the molecular weight distribution became wider. The copolymers can play the role of compatibilizer to improve the compatibility of blends. The dispersed particle size of disperse phase is significantly reduced w

9、ith increasing reaction extent.Secondly, the crystallization behavior, crystalline morphology, and crystal structure of the blends are studied. It had been showed that the PA6IcoT in the blends hinders the crystallization of PBS, leading to higher activation energy, slow crystal growth rate and low

10、crystallinity. This trend is enhanced by the increasing irregularity of macromolecular chain caused by the ester-amide exchange reaction. With the increase of reaction extent, spherulite size is gradually decreased and interface between spherulites become indistinctly. Although there is little diffe

11、rence in crystal structure, diffraction peaks appear drift. In the end, the relations between thermal property, mechanical property and degradation property and chemical structure and condensed state structure of blends are studied. The results show that the glass transition temperature of two polym

12、ers shifted gradually toward the middle due to exchange reaction. The incorporation of aromatic group into copolymer chain can suppress its thermal decomposition rate. The physical blend of PBS and nylon has worse mechanical properties than PBS due the compatibility between two polymers. On the othe

13、r hand, the products of reactive blending have much better tensile strength and module, and impact strength than PBS. With the increase in exchange reaction, the rate of polymer degradation is increased due to lower crystallinity and higher randomness. Therefore, poly(ester amide)s with better enhan

14、ced thermal property mechanical property and biological degradability are produced.【关键词】生物降解聚合物 PBS PA6IcoT 反应共混 交换反应【英文关键词】Biodegradable Polymers PBS PA6IcoT Reactive Blending Exchange Reaction【目录】PBS-PA6IcoT交换反应及其产物研究致谢4-5摘要5-6Abstract6-7第1章 前言10-12第2章 文献综述12-302.1 生物降解高分子材料的研究进展12-132.1.1 生物降解高分子

15、材料简介122.1.2 生物降解高分子材料分类12-132.2 脂肪族聚酯的研究进展13-142.3 PBS的改性研究14-212.3.1 共混改性14-162.3.2 共聚改性16-182.3.3 扩链改性18-212.4 聚酯酰胺研究进展21-292.4.1 单体法21-242.4.2 聚合物法24-292.5 课题提出29-30第3章 PBS和PA6IcoT间的交换反应及其结构表征30-483.1 引言303.2 实验部分30-323.2.1 实验原料30-313.2.2 反应共混313.2.3 溶解度实验313.2.4 分析测试31-323.3 结果与讨论32-463.3.1 溶解性分析32-343.3.2 反应机理分析34-383.3.3 结构分析38-433.3.4 分子量及其分布43-443.3.5 相形态分析44-463.4 本章小结46-48第4章 PBS和PA6IcoT熔融共混物的结晶动力学研究48-644.1 引言484.2 实验部分48-494.2.1 共混物制备484.2.2 分析测试48-494.3 结果与讨论49-624.3.1 等温结晶