摘 要

聚乳酸（PLA），又称聚丙交酯，是以乳酸为单体聚合而成的一类脂肪族聚酯，由于具有原料充足、机械性能优越、生物可降解等特点，使其成为当前高分子材料界探究的焦点，它也有结晶性能差、热稳定性差和亲水性差等缺点，用亲水性的葡萄糖可改善其不足，从而拓展聚乳酸材料的应用范围。聚乳酸根据其光学活性可以分为聚L-乳酸(PLLA)、聚D-乳酸(PDLA)，二者可制备机械性能更佳的立构复合物。本论文使用L-乳酸、D-乳酸和葡萄糖为原料，以熔融聚合法制备PLLA、PDLA、聚L-乳酸葡萄糖共聚物（PLLAG）和聚D-乳酸葡萄糖共聚物(PDLAG)。采用溶液共混法制备复合膜，并对其用氯仿与葡萄糖/DMF溶液进行表面改性，研究原料配比与制备工艺路线对共混物体系的影响，研究不同两亲性立构复合物的结构与性能。通过傅立叶变换红外光谱（FT-IR）、X射线衍射分析（XRD）、差示扫描量热法（DSC）、热重分析（TGA）、偏光显微镜（POM）和接触角测试的方法对立构复合物进行了表征，结果表明，等比例PLLAG/PDLAG体系与通过不同路径共混得到的四混复合物体系中均仅存在立构复合结晶，经过改性后的聚乳酸结晶性能与热稳定性有了大幅提高，并且经过葡萄糖微溶胀表面改性的聚乳酸复合膜亲水性也有显著提升。

关键词：聚乳酸；葡萄糖；两亲共聚物；立构共混；表面改性

Study on the stereocomplex structure of polylactic acid amphiphilic copolymer containing glucose group

ABSTRACT

Poly(lactic acid) (PLA), also known as polylactide, is a kind of aliphatic polyester polymerized by using lactic acid as a monomer. It has the characteristics of sufficient raw materials, superior mechanical properties and biodegradability. The focus of the material industry is that it also has the disadvantages of poor crystallinity, poor thermal stability and poor hydrophilicity. The use of hydrophilic glucose can improve its deficiency and expand the application range of poly(lactic acid) materials. PLA can be classified into poly-L-lactic acid (PLLA) and poly-D-lactic acid (PDLA) according to its optical activity, and both can prepare the stereocomplex having better mechanical properties. In this paper, PLLA, PDLA, poly-L-lactic acid glucose copolymer (PLLAG) and poly D-lactic acid glucose copolymer (PDLAG) were prepared by melt polymerization using L-lactic acid, D-lactic acid and glucose as raw materials. The composite membrane was prepared by solution blending method, and its surface modification was carried out with chloroform and glucose/DMF solution. The effects of raw material ratio and preparation route on the blend system were studied, and the structure and performance of different amphiphilic stereocomplexes were studied. Orthogonal composite by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction analysis (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), polarized light microscopy (POM) and contact angle test. The characterization of the material showed that the isotactic PLLAG/PDLAG system and the tetra-mixed composite system obtained by blending different paths only existed stereocomplex crystallization. The modified polylactic acid has deeply improved its crystallinity and thermal stability and the hydrophilicity of the polylactic acid composite membrane modified by the micro-swelling surface of glucose is also greatly improved.

Keyword: Poly（lactic acid）; Glucose; Amphiphilic copolymer; Stereo blend; Surface modification

目 录

第一章 绪论 1

1.1 研究背景 1

1.2 聚乳酸 1

1.2.1 聚乳酸的性质 2

1.2.2 聚乳酸的应用及研究进展 2

1.3 葡萄糖的性质 3

1.4 聚乳酸的改性及研究进展 4

1.4.1 聚乳酸的共混改性 4

1.4.2 聚乳酸的共聚改性 6

1.4.3 表面改性 8

1.5 研究目的与意义 8

第二章 含葡萄糖基团聚乳酸两亲性共聚物及其立构复合膜的制备 10

2.1 前言 10

2.2 实验原料和方法 10

2.2.1 原料 10

2.2.2 PLLA与PDLA的制备 11

2.2.3 PDLAG与PLLAG的制备 11

2.2.4 等比例PLLAG/PDLAG和PLLA/PDLA/PDLAG/PDLAG共混物膜的制备 12

2.2.5 共混物膜的表面改性 13

2.2.6 样品的表征 14

第三章 实验结果与讨论 15

3.1红外光谱（FT-IR）分析 15

3.1.1等比例PLLAG/PDLAG与PLLA的红外光谱 15

3.1.2四混-1、四混-2、四混-3与PLLA的红外光谱 16

3.2 X射线衍射分析（XRD） 17

3.3差示扫描量热法（DSC）分析 18

3.4 热重分析(TGA) 20

3.5偏光显微镜照片（POM）分析 23

3.6接触角分析 25

第四章 结论与展望 33

4.1 结论 33

4.2 展望 33

致 谢 35

参考文献 36

第一章 绪论

• 1. 研究背景

聚乳酸（PLA），又称聚丙交酯，是以乳酸为单体聚合而成的一类脂肪族聚酯。而乳酸可以通过玉米、木薯类作物进行发酵得到，原料来源广泛并且可以再生，聚乳酸在微生物作用下最终可以降解成二氧化碳和水，对环境危害很小，如图1-1。聚乳酸本身具有良好的生物相容性、无毒以及有较好的机械性能等优点，为此，聚乳酸作为一种环保的生物可降解材料，近年来发展较快^[1]。