Polycondensation, cyclization and disproportionation of solid Poly(L-lactide) trifluoroethyl esters and the simultaneous formation of extended chain crystals and extended ring crystals

IF 4.1 2区化学 Q2 POLYMER SCIENCE

Polymer Pub Date : 2024-11-09 DOI:10.1016/j.polymer.2024.127800

Steffen M. Weidner , Felix Scheliga , Hans R. Kricheldorf

{"title":"Polycondensation, cyclization and disproportionation of solid Poly(L-lactide) trifluoroethyl esters and the simultaneous formation of extended chain crystals and extended ring crystals","authors":"Steffen M. Weidner , Felix Scheliga , Hans R. Kricheldorf","doi":"10.1016/j.polymer.2024.127800","DOIUrl":null,"url":null,"abstract":"<div><div>Two poly(L-lactide)s (PLAs) with a degree of polymerization (DP) of 20 or 100 were prepared by trifluoroethanol-initiated ring-opening polymerization (ROP) catalyzed by tin(II) 2-ethyl hexanoate (SnOct<sub>2</sub>). These PLAs were annealed at 140 °C or at 160 °C in the presence of SnOct<sub>2</sub>, and the changes in topology and molecular weight distribution (MWD) were monitored by matrix-assisted laser desorption/ionization time-of-flight (MALDI TOF) mass spectrometry and gel permeation chromatography (GPC). For the PLA with a DP 20, the main reaction was polycondensation combined with higher dispersities. In the case of the DP 100, PLA polycondensation was combined with disproportionation and the formation of a new MWD maximum around <em>m/z</em> 3500. In addition, extensive cyclization occurred, and the resulting cyclic PLAs crystallized separately from the linear chains in the form of extended ring crystals. These results also suggest that both extended chain and extended ring crystals posses the same crystal thickness as a result of thermodynamically controlled transesterification in the solid state.</div></div>","PeriodicalId":405,"journal":{"name":"Polymer","volume":"315 ","pages":"Article 127800"},"PeriodicalIF":4.1000,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Polymer","FirstCategoryId":"92","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0032386124011364","RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"POLYMER SCIENCE","Score":null,"Total":0}

引用次数: 0

Abstract

Two poly(L-lactide)s (PLAs) with a degree of polymerization (DP) of 20 or 100 were prepared by trifluoroethanol-initiated ring-opening polymerization (ROP) catalyzed by tin(II) 2-ethyl hexanoate (SnOct₂). These PLAs were annealed at 140 °C or at 160 °C in the presence of SnOct₂, and the changes in topology and molecular weight distribution (MWD) were monitored by matrix-assisted laser desorption/ionization time-of-flight (MALDI TOF) mass spectrometry and gel permeation chromatography (GPC). For the PLA with a DP 20, the main reaction was polycondensation combined with higher dispersities. In the case of the DP 100, PLA polycondensation was combined with disproportionation and the formation of a new MWD maximum around m/z 3500. In addition, extensive cyclization occurred, and the resulting cyclic PLAs crystallized separately from the linear chains in the form of extended ring crystals. These results also suggest that both extended chain and extended ring crystals posses the same crystal thickness as a result of thermodynamically controlled transesterification in the solid state.

Abstract Image

查看原文本刊更多论文

固体聚（L-内酯）三氟乙酯的缩聚、环化和歧化以及延伸链晶体和延伸环晶体的同时形成

在 2- 乙基己酸锡（II）（SnOct2）催化下，通过三氟乙醇引发的开环聚合（ROP）制备了聚合度（DP）为 20 或 100 的两种聚乳酸（PLA）。这些聚乳酸在 SnOct2 的存在下于 140 ℃ 或 160 ℃ 退火，并通过基质辅助激光解吸/电离飞行时间（MALDI TOF）质谱法和凝胶渗透色谱法监测拓扑结构和分子量分布（MWD）的变化。对于 DP 20 的聚乳酸，主要反应是缩聚和较高的分散度。对于 DP 值为 100 的聚乳酸，缩聚反应与歧化反应相结合，并在 m/z 3 500 附近形成了新的最大截留分子量。此外，还出现了广泛的环化现象，由此产生的环状聚乳酸与线性链分开结晶，形成延伸的环状晶体。这些结果还表明，由于固态热力学控制的酯交换作用，延伸链和延伸环晶体具有相同的晶体厚度。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

来源期刊

Polymer 化学-高分子科学

CiteScore

7.90

自引率

8.70%

发文量

959

审稿时长

32 days

期刊介绍： Polymer is an interdisciplinary journal dedicated to publishing innovative and significant advances in Polymer Physics, Chemistry and Technology. We welcome submissions on polymer hybrids, nanocomposites, characterisation and self-assembly. Polymer also publishes work on the technological application of polymers in energy and optoelectronics. The main scope is covered but not limited to the following core areas: Polymer Materials Nanocomposites and hybrid nanomaterials Polymer blends, films, fibres, networks and porous materials Physical Characterization Characterisation, modelling and simulation* of molecular and materials properties in bulk, solution, and thin films Polymer Engineering Advanced multiscale processing methods Polymer Synthesis, Modification and Self-assembly Including designer polymer architectures, mechanisms and kinetics, and supramolecular polymerization Technological Applications Polymers for energy generation and storage Polymer membranes for separation technology Polymers for opto- and microelectronics.