Baroplastic properties of polymer blends formed by solution mixing

Baroplastic materials refer to polymers that undergo phase transitions due to pressure even below their glass transition temperature. In this study, we examined the pressure-induced miscibility of polymer pairs, including polymethylmethacrylate (PMMA) with polyvinyl chloride (PVC), polystyrene (PS) with polycarbonate (PC), and polycaprolactone (PCL) with polyethylmethacrylate (PEMA), by mixing them in solution. Each polymer pair was combined in a 1 : 1 mass ratio and subsequently dried. PMMA/PVC was compression molded at temperatures ranging from 90℃ to 140℃, PS/PC from 100℃ to 150℃, and PCL/PEMA at 70℃, with transparency being monitored to observe pressure-induced miscibility. The results indicated that pressure-induced miscibility could be achieved through solution mixing; however, the effects of repeated molding cycles were not observed. This suggests that effective baroplastic properties require nanoscale mixing. Nevertheless, the PMMA/PVC combination exhibited superior baroplastic properties even with solution mixing, likely due to the inherent compatibility between PMMA and PVC.