低摩尔质量的循环聚L-乳化物:在固态中,循环和线性链的单独转化反应
Hans R Kricheldorf1, Steffen M Weidner2
1Universität Hamburg, Institut für Technische Chemie und Makromolekulare Chemie, Bundesstr. 45, D-20146 Hamburg, Germany. hrkricheldorf@aol.de.
Soft matter
|July 23, 2024
概括
这项研究使用 (II) 2-乙烯基酸盐合成了循环多聚化物 (cPLA). 化揭示了线性和循环链之间的明显的转化行为,由热力学控制控制.
科学领域:
- 聚合物化学 聚合物化学
- 材料科学 材料科学 材料科学
- 有机合成 有机合成
背景情况:
- 聚酸 (PLA) 是一种具有多种应用的可生物降解聚合物.
- 控制PLA的架构,特别是循环形式 (cPLA),对于定制材料特性至关重要.
- 了解PLA的聚合和降解机制对于其可持续使用至关重要.
研究的目的:
- 通过L-Lactide (LA) 的环开放聚合 (ROP) 来研究循环多聚化物 (cPLA) 的合成.
- 探索cPLAs的化行为,并比较线性和周期性PLA链的转化反应.
- 为了阐明控制化过程中PLA链重新排列的热力学控制.
主要方法:
- 使用 (II) 2-乙烯酸盐 (SnOct2) 在烯中对L-乳酸盐 (LA) 进行环开放聚合 (ROP).
- 使用MALDI-TOF质谱法对循环多聚化物 (cPLA) 进行表征,以确定分子重量和链结构.
- 在高温下在不同催化剂 (ScOct2,DSTL) 的存在下对晶体cPLA进行火实验.
主要成果:
- 合成具有数量平均分子量 (Mn) 从7000到17000的cPLAs,以及一小部分线性链.
- 由于cPLA的化,无论使用哪种催化剂,都会形成延长线性链和延长循环的结晶体.
- 通过形成低分散度的延长链结晶体,观察到对比例的证据,表明链长度重新分配.
结论:
- 在回火过程中,在热力学控制下的线性和周期性PLA链的转化反应的过程不同.
- 延长链结晶体的形成表明,这是一种涉及链长度再分配的对比机制.
- 催化剂的选择会影响PLA化过程中的转化途径,影响最终的晶体结构.
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