广东工业大学雷彩虹团队报道了热定型温度对PP/HDPE双层微孔膜微孔结构及性能的影响。相关研究成果于2024年6月26日发表于国际顶尖学术期刊《中国高分子科学杂志》。

由于PP层的机械稳定性，PP/HDPE双层微孔膜可以在比PE单层膜更高的热定型温度下制备。研究人员分析了热定型温度对PP/HDPE双层膜孔结构和性能的影响。随着热定形温度从120°C增加到130°C，由于薄片的熔化和热定形过程中连接桥结构的稳定性，PE层中连接桥晶体的长度和结晶度增加。热定型微孔膜相应的透气性、孔隙率、液体电解质的润湿性和力学性能都有所提高，表现出更好的电化学性能。

然而，当热定形温度进一步提高到140°C，高于PE树脂的熔点时，由于片层和连接桥在热定形过程中熔化和收缩，导致透气性和孔隙率降低，因此一些孔隙闭合。相反，在上述热定形温度区域内，PP层的变化可忽略不计。

该研究成功地建立了微孔膜在热定型过程中稳定的孔结构与性能之间的关系，有助于指导高性能PP/PE/PP锂电池隔膜的生产。

附：英文原文

Title: Influence of Heat-setting Temperature on the Microporous Structure and Properties of PP/HDPE Bilayer Microporous Membranes

Author: Jie Xie, Yong-Shi Wu, Jia-Yi Xie, Rui-Jie Xu, Cai-Hong Lei, Sai-Nan Song, Guang-Quan Li, An-Ping Huang

Issue&Volume: 2024-06-26

Abstract: Due to the mechanical stability of PP layer, the PP/HDPE double-layer microporous membrane could be prepared at a higher heat-setting temperature than that of PE monolayer membrane. In this work, the effects of heat-setting temperature on the pore structure and properties of PP/HDPE double-layer membrane were studied. With the increase of heat-setting temperature from 120 °C to 130 °C, the length of connecting bridge crystal and crystallinity in the PE layer increase due to the melting of thin lamellae and the stability of connecting bridge structure during heat-setting. The corresponding air permeability, porosity, wettability of liquid electrolyte and mechanical property of the heat-set microporous membrane increase, exhibiting better electrochemical performance. However, when the heat-setting temperature is further increased to 140 °C, higher than the melting point of PE resin, some pores are closed since the lamellae and connecting bridges melt and shrink during heat-setting, resulting in a decrease of air permeability and porosity. In contrast, there is negligible change in the PP layer within the above heat-setting temperature region. This study successfully builds the relationship between the stable pore structure and property of microporous membrane during heat-setting, which is helpful to guide the production of high-performance PP/PE/PP lithium batteries separator.

DOI: 10.1007/s10118-024-3157-x

Source: https://www.cjps.org/en/article/doi/10.1007/s10118-024-3157-x/