本文選題：聚乳酸 + 溶液聚合��； 參考：《哈爾濱理工大學》2010年碩士論文

【摘要】： 聚乳酸是一種以玉米淀粉等可再生資源為起始原料來生產(chǎn)的可生物降解高分子材料,聚乳酸無毒,無刺激性,具有優(yōu)良的生物相容性、生物可吸收性、生物可降解性,同時還具有優(yōu)良的物理、力學性能。 本文采用溶液聚合的方法,使單體D, L-乳酸通過直接聚合的方式合成聚乳酸,優(yōu)化了制備工藝,使聚乳酸的制備周期縮短。 首先以D, L-乳酸單體為原料,抽真空脫去乳酸單體中自身存在的游離水,研究了減壓脫水時間、脫水溫度、真空度對預除水過程的影響,確定合理的制備工藝條件為:先減壓脫水至乳酸溫度為80℃,真空度為-0.03MPa,脫水時間為3小時,使乳酸單體中的游離水脫除比較徹底,并為下一步乳酸直接聚合過程提供有利條件。 在上述實驗過程的基礎上,不斷的提高聚合反應體系的溫度,與此同時聚合反應體系的真空度也要逐步提高,并且加入催化劑無水氯化亞錫,嚴格控制聚合反應的工藝過程,探討了溶劑的選擇及其用量,催化劑種類及其用量,聚合反應所需的時間,聚合反應體系的溫度,聚合反應體系的真空度,聚合反應末期加入分子篩脫水、反應過程通入氮氣保護等工藝條件對聚乳酸制品分子量,以及產(chǎn)物顏色狀態(tài)的影響。 采用溶液聚合的方法合成聚乳酸的最佳的工藝條件為:聚合反應的催化劑為無水氯化亞錫,其用量為乳酸單體的0.25 wt%,聚合反應時間為24h,聚合反應溫度為160℃,聚合反應真空度-0.09MPa。按照此最佳工藝條件進行聚乳酸的制備,最終得到聚乳酸的粘均分子量Mη近2萬。通過對聚合物的紅外光譜的分析,證明了合成產(chǎn)物是聚乳酸。
[Abstract]:Polylactic acid (PLA) is a biodegradable polymer material produced from corn starch and other renewable resources. Polylactic acid is non-toxic, non-irritating, and has excellent biocompatibility, bioabsorbability and biodegradability. At the same time, it also has excellent physical and mechanical properties. Polylactic acid was synthesized by direct polymerization of monomer D, L-lactic acid by solution polymerization. The preparation process was optimized and the preparation period of polylactic acid was shortened. At first, using DL- lactic acid monomer as raw material, the effects of dehydration time, dehydration temperature and vacuum degree on the pre-removal process were studied by vacuum desorption of free water from lactate monomer. The optimum preparation conditions were determined as follows: dehydration at 80 鈩，

本文編號：1826892