Facial Preparation of Segregated Poly(butylene succinate)/Carbon Nanotubes Composite Foams with Superior Conductive Properties via Synergistic Effect of High Pressure Solid Phase Molding and Supercritical Fluid Foaming

Conductive polymer composites (CPCs) have been demonstrated to have many advantages. However, agglomeration of conductive fillers or segregation of conductive networks in CPCs always results in weak mechanical properties and limited conductivity. To address this issue, four types of poly(butylene succinate)/multiwalled carbon nanotube (PBS/CNT) CPC with different conductive network structures are prepared: PBS/CNT-I: melt mixing with hot pressing (145 degrees C, 10 MPa), PBS/CNT-II: solution mixing with hot pressing (145 degrees C, 10 MPa), PBS/CNT-III: solution mixing with hot pressing (100 degrees C, 10 MPa), PBS/CNT-IV: solution mixing with hot pressing (100 degrees C, 60 MPa). The results show that PBS/CNT-IV CPC has the highest mechanical properties, conductivity, and thermal conductivity. Tensile strength, elongation at break and Young's modulus of PBS/CNT-IV are 119%, 58%, and 37% higher than that of PBS/CNT-III CPC, respectively. Subsequently, PBS/CNT-IV CPCs with different CNT contents are prepared. The mechanical, crystallization, electrical and thermal conductivities, and rheological properties as well as foamability are studied. Compared with PBS/5.0 wt.% CNT-IV CPC, the foamed specimen shows 97% enhancement in conductivity. In general, this work offers a simple, environmentally-friendly approach for manufacturing CPC with high conductivity and good mechanical property and is instructive for construction of a segregated network structure in low-melt-viscosity semi-crystalline polymer.