聚乳酸论文：聚乳酸合成及改性研究.doc

聚乳酸论文：聚乳酸合成及改性研究【中文摘要】本文主要研究用杂多酸作为催化剂合成聚乳酸的方法,并优化其合成工艺以提高分子量,同时还对聚乳酸改性共聚物聚乳酸-聚乙二醇(PLA-PEG)和聚(乳酸-甘氨酸)进行了初步的研究和探讨。首先,研究了用固体杂多酸磷钨酸为催化剂,直接法合成聚乳酸。以傅立叶红外光谱(FTIR)和X射线衍射(XRD)检测,确定磷钨酸结构和晶形结构,并通过FTIR分析及粘度法对聚乳酸的结构及相对分子质量进行检测。实验得出了以磷钨酸为催化剂合成聚乳酸的最佳工艺条件为磷钨酸用量为乳酸质量0.5%,真空度1-2kPa,温度170,反应时间6h,得到一定粘均分子量的聚乳酸。其次,采用开环聚合法,固体超强酸S042-/Zr02-Ce02为催化剂,催化丙交酯和聚乙二醇合成PLA-PEG嵌段共聚物,研究了聚乙二醇(PEG)分子量、反应时间、温度、催化剂用量等条件对共聚物的影响,并通过FTIR、Hammett指示剂法及NH3-TPD等方法对固体超强酸的酸性质进行了表征。研究结果表明当焙烧温度为650时,得到的固体超强酸S042-/Zr02-Ce02酸强度与酸量最大,用该催化剂催化合成PLA-PEG嵌段共聚物,当PEG分子量6000、反应时间9h、反应温度170、催化剂用量为丙交酯质量分数的1.0%时,得到PLA-PEG共聚物的特性粘度最大,为1.693dlg-1。最后,进行了氨基酸对聚乳酸的改性研究。以丙交酯和甘氨酸为原料,将甘氨酸制成环状单元吗啉-2,5-二酮,丙交酯与吗啉-2,5-二酮开环共聚,通过FTIR与核磁(1H-NMR)确定产物即为聚(乳酸-甘氨酸)。并通过实验探索出较为适宜的工艺条件为：催化剂辛酸亚锡用量为丙交酯质量0.3%,温度160,反应时间8h,得到的共聚物特性粘度最高,可达到0.91dlg-1。【英文摘要】A method for synthesizing polylactic acid with heteropoly acid as catalyst, and optimizing reaction conditions of PLAs polymerization. Also basic research of synthesis copolymer PLA-PEG and P(LA-co-Gly) were probed.Firstly, the synthesis of polylactides by direct condensation polymerization catalyzed by phosphotungstic acid was studied. The structure and crystalline structure of phosphotungstic acid were determined by infrared FTIR and XRD. And the microstructure, viscosity average molecular weight of PLA were investigated by Fourier transform infrared FTIR, and viscosity meter. The comparatively appropriate reaction conditions were as follows:the content of phosphotungstic acid was 0.5wt% of lactic acid, polymerized at 170for 6h under a system vacuum of 1-2kPa. As a result, a certain viscosity average molecular weight was got.Secondly, the PLA-PEG block polymer catalyzed by solid super acid SO42-/ZrO2-CeO2 was prepared by opening ring polymerization. The acidic property was measured by IR spectra, Hammett Indicator and NH3-TPD techniques. The effects of molecular weight of PEG, reaction time, temperature and catalyst amount on copolymer were studied, and the characteristic group of copolymer was measured by FTIR spectra. The solid super acid SO42-/ZrO2-CeO2 had the strongest acid strength and maximal acid content roasted at 650. The optimum reaction conditions were obtained, which were the amount of catalyst 1.0% vs lactic, the molecular weight of PEG6000, polymerization at 170for 9h. The intrinsic viscosity reached 1.693dlg-1.Lastly, the synthesis research of polylactic acid modified by a amino acid was done. With the lactide(LA) and glycine (Gly) as the stanting materials, Gly was made into the cricoid unit morpholine-2,5-dione, then LA and Gly was reacted by opening ring copolymerization, FTIR and 1H-NMR made sure the copolymer was P(LA-co-Gly). And got a comparatively appropriate reaction conditions by exploring, as follows:the content of the catalyst Sn(Oct)2 was 0.3% of that of LA, temperature was 160, reaction time was 8h. The viscosity reached 0.91dlg-1, which could meet the requests for the application in drug delivery of this biodegradable material.【关键词】聚乳酸 杂多酸 固体超强酸 共聚物【英文关键词】polylactic acid heteropoly acid solid superacid copolymer【目录】聚乳酸合成及改性研究摘要3-4ABSTRACT4-5第1章 引言9-231.1 概述9-101.2 聚乳酸的性质101.3 聚乳酸的合成10-171.3.1 聚乳酸直接缩聚法11-141.3.2 聚乳酸开环聚合法14-171.4 聚乳酸改性研究17-221.4.1 聚乳酸的共聚改性17-201.4.2 聚乳酸的共混改性20-211.4.3 聚乳酸的复合改性211.4.4 聚乳酸的增塑改性21-221.5 选题意义和研究内容221.6 文章创新点22-23第2章 实验部分23-252.1 实验药品23-242.2 实验设备及仪器24-25第3章 磷钨杂多酸催化剂熔融缩聚法合成聚乳酸25-363.1 实验内容26-273.1.1 磷钨酸催化剂的合成263.1.2 磷钨酸直接催化聚乳酸的合成26-273.2 合成磷钨酸的表征27-293.2.1 红外谱图分析27-283.2.2 XRD谱图分析28-293.3 本体熔融法直接合成聚乳酸的工艺研究29-323.3.1 催化剂用量对聚乳酸分子量的影响29-303.3.2 聚合温度对聚乳酸分子量的影响30-313.3.3 反应时间对聚乳酸分子量的影响31-323.4 合成聚乳酸的表征32-333.5 乳酸直接合成聚乳酸引发机制初探33-353.6 本章小结35-36第4章 PLA-PEG共聚物的合成36-474.1 PLA-PEG嵌段共聚物的合成36-374.1.1 负载法制备固体超强酸催化剂36-374.1.2 丙交酯的合成374.1.3 PLA-PEG共聚物的合成374.2 固体超强酸催化剂的分析37-404.2.1 固体超强酸红外谱图分析37-384.2.2 固体超强酸酸强度对PLA-PEG共聚物的影响38-394.2.3 催化剂NH_3-TPD分析39-404.3 聚合工艺条件对共聚物的影响40-444.3.1 PEG分子量对嵌段共聚物的影响40-414.3.2 反应时间对共聚物的影响41-424.3.3 反应温度对共聚物的影响42-434.3.4 催化剂用量对共聚物的影响43-444.4 共聚物及丙交酯的红外谱图分析44-464.5 本章小节46-47第5章 氨基酸改性聚乳酸的合成47-595.1 氨基酸改性聚乳酸的合成47-495.1.1 N-氯乙酰基甘氨酸的合成47-485.1.2 吗啉-2,5-二酮的合成485.1.3 共聚物的合成48-495.2 N-氯乙酰基甘氨酸的合成结果分析49-515.2.1 红外谱图分析49-505.2.2 合成工艺讨论50-515.3 吗啉-2,5-二酮的合成结果分析51-54