Flexible, antibacterial porous phase change thermal management film prepared by a one-step extrusion casting-foaming method

Flexible antibacterial thermal management products with long working duration are highly desirable for personalized healthcare applications, such as thermotherapy. However, the preparation of products that can meet all these requirements is still under development. In this study, we prepared a flexible porous phase change foaming film (PCFF) by a facile one-step extrusion casting-foaming method, in which thermal expansion microspheres (EMs) were used as the foaming agent to foam a poly(styrene-b-(ethylene-co-butylene)-b-styrene (SEBS)/paraffin-based phase change system containing an antibacterial agent-grafted functional polypropylene (ab-PP) masterbatch. The addition of the ab-PP masterbatch not only improved the processability of the blend system but also imparted the PCFF with almost 100% antibacterial rate against both Escherichia coli and Staphylococcus aureus. The phase change of paraffin and presence of abundant pores within the resulting foaming film bestowed the PCFF with excellent long-duration temperature stability. For a stack composed of 5 layers PCFFs with a total thickness of 3.7 mm and mass of only 16.2 g, the duration of temperature decrease from 48 to 35 degrees C (simulating the thermotherapy temperature for the human body) is longer than 10 minutes. The resultant PCFF exhibited excellent flexibility, antibacterial performance and exothermic ability, which made it a promising prospect in wearable thermotherapy fields. A SEBS/paraffin/PP phase change foaming film was prepared through a one-step melt extrusion casting-foaming technology, and its application potential in thermal therapy was demonstrated.