Global energy issues are becoming increasingly prominent, and have caused widespread attention. Lightweight, thermal insulation, environmentally friendly and recyclable polymeric foam materials exhibit a great application prospects in reducing energy consumption, saving resources and improving utilization. However, there are huge challenges in preparation of such high thermal insulation materials. Herein, recyclable, high mechanical strength and thermal insulation polypropylene (PP) foams were achieved by supercritical CO₂ foaming in the presence of β nucleating agent (β-NAs). The obtained PP-β foam exhibited a variety of advantages, including high expansion ratio, continuous honeycomb polygonal cells, a very low thermal conductivity of 26.4 mW/m•K, strong tensile and compressive strength, as well as recyclable property. The accelerated crystallization process, decreased crystal size, and enhanced viscoelasticity caused by the β-NAs contributed to the formation of the multifunctional PP foams. The honeycomb polygonal cells greatly increased the curved path of heat propagation and reduced heat transfer efficiency, as well as enhanced the mechanical properties. Moreover, the compressed PP-β foam still possessed excellent thermal insulation property, as low as 37.1 mW/m•K. The recyclable multifunctional PP foam materials achieved by using physical foaming technology provided a potential solution for the preparation of multifunctional thermal insulation materials, which offered a big application prospect for polymer foam materials in the fields of reducing energy loss.

全球能源问题变得日益突出，并引起了广泛关注。轻质，隔热，环保和可回收的聚合物泡沫材料在降低能耗，节省资源和提高利用率方面显示出巨大的应用前景。然而，在制备这种高绝热材料方面存在巨大挑战。在此，通过超临界CO ₂获得了可回收的，高机械强度和隔热的聚丙烯（PP）泡沫。在β成核剂（β-NAs）存在下发泡。所得的PP-β泡沫显示出多种优点，包括高膨胀比，连续的蜂窝状多边形孔，26.4mW / m·K的非常低的导热率，强的拉伸和压缩强度以及可回收的特性。β-NA引起的加速结晶过程，减小晶体尺寸和增强粘弹性有助于形成多功能PP泡沫。蜂窝状多边形单元极大地增加了热传递的弯曲路径并降低了热传递效率，并增强了机械性能。而且，压缩的PP-β泡沫仍具有优异的绝热性能，低至37.1mW / m·K。