Yang Chenguang, Xu Yangkang, Liu Haiyang, Yan Kun, Wang Wenwen, Zhao Qinghua, Wang Dong
Key Laboratory of Textile Fiber and Products (Wuhan Textile University), Ministry of Education, Wuhan Textile University, Wuhan 430200, China.
College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620, China.
Langmuir. 2025 Mar 4;41(8):5546-5556. doi: 10.1021/acs.langmuir.4c05256. Epub 2025 Feb 18.
Polypropylene (PP) foam is a potential high-temperature insulating porous material with high mechanical properties and service temperature. However, the development of insulating and multifunctional foams based on PP still faces challenges. In this study, grafting by ultraviolet (UV) radiation was successfully used to introduce ester-based groups into PP molecular chains. The grafted product was then blended with pure PP in a specified proportion and pelletized, and then subjected to chemical foaming to obtain the modified rigid PP foams. The grafted PP effectively reduced the melt flow rate and heterogeneous nucleation during foaming, improved foaming efficiency, and promoted the formation of nanometer- and micron-sized cells. The newly introduced ester-based groups also effectively absorbed near- and far-infrared radiative energy; meanwhile, the nanometer- and micron-sized cells effectively enhanced the Knudsen and Phonon Scattering Effects, resulting in a significant reduction in the thermal conductivity, from 186.7 to 65.3 mW/(m·K). Moreover, the obtained foam exhibited well mechanical and hydrophobic properties under complex environmental conditions. The ester-based multiscale porous PP foam demonstrated simultaneous reduction in the radiation heat transfer coefficient, solid thermal conductivity, and gas thermal conductivity, thereby providing a new strategy for further reducing the thermal conductivity of polymer-based foams and achieving excellent insulation. This work realized the preparation of difficult-to-make rigid PP foams, laying the foundation for further diversification of PP foams and expanding their application areas.
聚丙烯（PP）泡沫是一种具有高机械性能和使用温度的潜在高温绝缘多孔材料。然而，基于PP的绝缘多功能泡沫的开发仍面临挑战。在本研究中，成功利用紫外线（UV）辐射接枝将酯基引入PP分子链中。然后将接枝产物与纯PP按特定比例共混并造粒，接着进行化学发泡以获得改性硬质PP泡沫。接枝PP有效降低了发泡过程中的熔体流动速率和异相成核，提高了发泡效率，并促进了纳米级和微米级泡孔的形成。新引入的酯基还有效吸收了近红外和远红外辐射能；同时，纳米级和微米级泡孔有效增强了克努森效应和声子散射效应，导致热导率显著降低，从186.7降至65.3 mW/(m·K)。此外，所得泡沫在复杂环境条件下表现出良好的机械性能和疏水性。酯基多尺度多孔PP泡沫同时降低了辐射传热系数、固体热导率和气体热导率，从而为进一步降低聚合物基泡沫的热导率并实现优异隔热提供了新策略。这项工作实现了难以制备的硬质PP泡沫的制备，为PP泡沫的进一步多样化及其应用领域的拓展奠定了基础。
