The formation of a segregated structure in conductive polymer composites (CPCs) is one of the most promising strategies for achieving good electrical conductivity and electromagnetic interference (EMI) shielding performance. Nevertheless, the segregated CPCs usually suffer from deteriorated mechanical properties due to the limited interfacial interaction between polymer granules hindered by the conductive layer. We propose a novel sintering method utilizing the intense selective heating of conductive fillers upon microwave irradiation, which shows obvious advantages over conventional compression molding (CM). To do so, carbon nanotubes (CNTs) were used as microwave absorbers in the thermoplastic polyurethane (TPU) media. Upon irradiation, CNTs were responsible for a local temperature increasing spot on the surface of TPU granules, promoting the molecular diffusion among TPU only in the interface region without damaging the segregated structure. In this way, the elongation at break of the as-prepared TPU/CNT composites reached 350%, approximately ten times higher than that of the composites prepared by the conventional CM. Meanwhile, the microwave sintering (MS) composites showed comparable electrical conductivity and EMI shielding effectiveness (SE) to the CM samples. Our current efforts provide an insight into the development of a highly stretchable EMI shielding material via the “green” method.

In this study, a novel poly (vinyl alcohol) (PVA)/poly (ethylene glycol) (PEG) scaffold was carefully designed via thermal processing and subsequent supercritical fluid (SCF) foaming. Interestingly, a bimodal open-celled structure with interconnected networks was successfully created in the plasticized PVA (WPVA)/PEG scaffold. Large cells were produced from the nucleation sites generated in the PVA phase during rapid depressurization, while plenty of small pores generate in the cell walls of the big cells. The formation mechanism of this cellular structure was studied by considering the various phase morphologies and the diffusion behaviour of the carbon dioxide (CO₂) in individual phases. In addition, the intermolecular interactions of the WPVA/PEG blend were studied using X-ray diffraction and FTIR analysis. The results demonstrate that various types of hydrogen bonds among the hydroxyl groups on the PVA chains, PEG and water molecules are formed in the blend system. The realization of thermoplastic foaming of the PVA/PEG blend benefits from the interactions of complexation and plasticization between water and PEG molecules. The SEM images also revealed that L929 fibroblast cells were able to attach and spread on surfaces of the WPVA/PEG samples. Thus the WPVA/PEG scaffold with unique bimodal cellular structure is nontoxic and favours the attachment and proliferation of cells, making it promising for use as the candidate for tissue engineering applications.