中国科学院宁波材料技术与工程研究所郑文革团队，报道了采用自组装成核剂的微孔注塑成型的轻质、强、高耐热聚乳酸泡沫。相关研究成果于2024年2月29日发表于国际顶尖学术期刊《中国高分子科学杂志》。

聚乳酸（PLA）泡沫已显示出相当大的前景，可作为不可降解塑料泡沫（如聚苯乙烯（PS）泡沫）的环保替代品。然而，PLA泡沫通常由于其固有的缓慢结晶速率和低熔体强度，而具有低耐热性和较差的蜂窝状结构。

该研究中，研究人员通过芯背微孔注射成型（MIM）工艺成功制备了具有良好细胞形态、优异强度和增强耐热性的高性能PLA泡沫。差示扫描量热法（DSC）结果表明，添加肼基成核剂（HNA）显著提高了聚乳酸的结晶温度，加速了聚乳酸结晶过程。值得注意的是，添加1.5wt%的HNA导致PLA的细胞大小显著减小，从43.5μm减小到2.87μm，并且细胞密度显著增加，从1.08×10⁷个细胞/cm³增加到2.15×10¹⁰个细胞/cm³。

这种增强导致PLA共混泡沫的最终结晶度约为55.7%，与纯PLA泡沫相比有显著改善。此外，在1.5wt%HNA浓度下，PLA共混泡沫的拉伸强度和拉伸韧性分别显著提高了136%和463%。此外，PLA共混泡沫的维卡软化温度显著提高到134.8°C，而纯PLA泡沫仅表现出约59.7°C。

这些发现强调了制备具有增强韧性和耐热性的轻质注塑PLA泡沫的潜力，为生产适用于大规模应用的高性能PLA泡沫提供了一种可行的方法。

附：英文原文

Title: Lightweight, Strong and High Heat-Resistant Poly(lactide acid) Foams via Microcellular Injection Molding with Self-Assembly Nucleating Agent

Author: Xiao-Hu Bing, Wen-Yu Ma, Ming-Hui Wu, Peng Gao, Xiao Zhou, Hai-Bin Luo, Long Wang, Wen-Ge Zheng

Issue&Volume: 2024-02-29

Abstract: Poly(lactide acid) (PLA) foams have shown considerable promise as eco-friendly alternatives to nondegradable plastic foams, such as polystyrene (PS) foams. Nevertheless, PLA foam typically suffers from low heat-resistance and poor cellular structure stemming from its inherent slow crystallization rate and low melt strength. In this study, a high-performance PLA foam with well-defined cell morphology, exceptional strength and enhanced heat-resistance was successfully fabricated via a core-back microcellular injection molding (MIM) process. Differential scanning calorimetry (DSC) results revealed that the added hydrazine-based nucleating agent (HNA) significantly increased the crystallization temperature and accelerated the crystallization process of PLA. Remarkably, the addition of a 1.5 wt% of HNA led to a significant reduction in PLA’s cell size, from 43.5 μm to 2.87 μm, and a remarkable increase in cell density, from 1.08×107 cells/cm3 to 2.15×1010 cells/cm3. This enhancement resulted in a final crystallinity of approximately 55.7% for the PLA blend foam, a marked improvement compared to the pure PLA foam. Furthermore, at 1.5 wt% HNA concentration, the tensile strength and tensile toughness of PLA blend foams demonstrated remarkable improvements of 136% and 463%, respectively. Additionally, the Vicat softening temperature of PLA blend foam increased significantly to 134.8 °C, whereas the pure PLA foam exhibited only about 59.7 °C. These findings underscore the potential for the preparation of lightweight injection-molded PLA foam with enhanced toughness and heat-resistance, which offers a viable approach for the production of high-performance PLA foams suitable for large-scale applications.

DOI: 10.1007/s10118-024-3088-6

Source: https://www.cjps.org/en/article/doi/10.1007/s10118-024-3088-6/