Supercritical carbon dioxide foamed thermoplastic polyester elastomer with poly(lactic acid) blending: shrinkage reduction and expansion ratio improvement

IF 2.2 4区 化学 Q3 CHEMISTRY, PHYSICAL
Zong-quan Gu, Bao-yan Zhao, Li Zhang, Jin-biao Bao
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引用次数: 0

Abstract

Thermoplastic polyester elastomer (TPEE) microcellular foam materials prepared using supercritical carbon dioxide (scCO2) as a physical blowing agent suffer from poor dimensional stability, which significantly limits their applications across various fields. This study thoroughly investigates the prevalent issues of high shrinkage and low expansion ratio in the scCO2 foaming process of TPEE. By introducing poly(lactic acid) (PLA), a rigid material with moderate compatibility, into TPEE through blend modification, we markedly improved the shrinkage behavior of foamed TPEE while enhancing its expansion ratio. The experiments successfully produced TPEE/PLA20 microcellular foams with a stable expansion ratio of 19 times. Compared to pure TPEE, the shrinkage rate decreased from 77.3 to 19.0%. Due to its moderate compatibility, PLA was uniformly dispersed within the TPEE matrix as a dispersed phase, which refined the cell structure through heterogeneous nucleation and reduced cell walls strain. Additionally, rigid PLA micro/nanoparticles acted as stress concentration points, promoting the formation of an open-cell structure by causing cell walls rupture, thereby accelerating gas diffusion. More importantly, high glass transition temperature (Tg) PLA nanoparticles are stretched and embedded in the cell walls during the foaming process, and the heterogeneous nucleation effect of PLA enhances the crystallinity of TPEE. These two factors together increase the rigidity of the cell walls. The synergistic effects of these factors enabled the TPEE/PLA microcellular foam materials to effectively resist shrinkage caused by the pressure differential between the inside and outside of the cells and molecular chain relaxation.

Graphical Abstract

超临界二氧化碳发泡热塑性聚酯弹性体与聚乳酸共混:缩小收缩、提高膨胀比
以超临界二氧化碳(scCO2)为物理发泡剂制备的热塑性聚酯弹性体(TPEE)微孔泡沫材料存在尺寸稳定性差的问题,这极大地限制了其在各个领域的应用。本研究深入探讨了TPEE在scCO2发泡过程中普遍存在的高收缩率、低膨胀率问题。通过共混改性,将相容性适中的刚性材料聚乳酸(PLA)引入TPEE中,显著改善了发泡TPEE的收缩性能,同时提高了其膨胀率。实验成功制备出膨胀率稳定在19倍的TPEE/PLA20微孔泡沫。与纯TPEE相比,收缩率由77.3%降至19.0%。由于PLA的相容性适中,它以分散相的形式均匀分散在TPEE基体中,通过非均相成核细化了细胞结构,降低了细胞壁应变。此外,刚性聚乳酸微/纳米颗粒作为应力集中点,通过引起细胞壁破裂促进开孔结构的形成,从而加速气体扩散。更重要的是,在发泡过程中,高玻璃化温度(Tg)的PLA纳米颗粒被拉伸并嵌入细胞壁中,PLA的非均相成核效应增强了TPEE的结晶度。这两个因素共同增加细胞壁的刚性。这些因素的协同作用使TPEE/PLA微孔泡沫材料能够有效抵抗细胞内外压差和分子链松弛引起的收缩。图形抽象
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来源期刊
Colloid and Polymer Science
Colloid and Polymer Science 化学-高分子科学
CiteScore
4.60
自引率
4.20%
发文量
111
审稿时长
2.2 months
期刊介绍: Colloid and Polymer Science - a leading international journal of longstanding tradition - is devoted to colloid and polymer science and its interdisciplinary interactions. As such, it responds to a demand which has lost none of its actuality as revealed in the trends of contemporary materials science.
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