熔融态聚碳酸酯结构演化与流变性能的相关性,Journal of Applied Polymer Science

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熔融态聚碳酸酯结构演化与流变性能的相关性
Journal of Applied Polymer Science ( IF 2.7 ) Pub Date : 2022-11-22 , DOI: 10.1002/app.53418
Mengdi Chen ₁ , Mingfu Zheng ₁ , Lu Zhang ₁ , Yunsheng Xu ₁ , Xianming Zhang ₁ , Wenxing Chen ₁

Affiliation

在这项工作中，利用多种流变学和分子结构表征方法研究聚碳酸酯 (PC) 在氮气气氛下高温 (260–300°C) 下的熔融后缩聚 (MPP) 过程。我们发现一些意想不到的现象，PC 熔体的复数粘度在 300°C 10 小时的 MPP 过程中迅速上升并达到约 10 ^{6 Pa·s 的异常高值。}分离可溶性 PC 和不溶性凝胶残留物，并通过凝胶渗透色谱分析这两种组分，¹H-NMR 和热解-气相色谱质谱法。结果表明，可溶性 PC 的分子量在反应早期（小于 1 小时）显着增加。之后由于长时间的高温反应引起的支化反应和降解反应的发生而继续减少。化学结构分析表明，在可溶性聚碳酸酯和不溶性凝胶残渣中都发现了相同的两个支化结构，结构的变化表明在交联反应过程中没有形成新的结构。根据这项研究的结果，我们清楚地了解了 PC 在 MPP 过程中的流变特性和结构变化之间的相关性。

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Correlation between structural evolution and rheological properties for polycarbonate in the molten state

In this work, multiple rheological and molecular structure characterization methods are utilized to investigate the melt post-polycondensation (MPP) process of polycarbonate (PC) at high temperatures (260–300°C) under a nitrogen atmosphere. We find some unexpected phenomena that the complex viscosity of PC melt rise rapidly and it reaches an extraordinarily high value of about 10⁶ Pa·s during the MPP process of 10 h at 300°C. Dissoluble PC and insoluble gel residue are separated and both fractions are analyzed by gel permeation chromatography, ¹H-NMR, and pyrolysis-gas chromatography mass spectrometry. Results show that the molecular weight of dissoluble PC significantly increases at the early stage of the reaction (less than 1 h). After that, it continues to reduce due to the occurrence of branching reactions and degradation reactions caused by high temperature reactions for a long time. Chemical structure analysis indicates that the same two branched structures are discovered in both dissoluble PC and insoluble gel residue, the changes in structures indicate that no new structures are formed during the crosslinking reaction. According to this study's results, we clearly understand the correlation between the rheological properties and structural changes for PC in the MPP progress.

更新日期：2022-11-22

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