Effect of Crosslinking Agent and Branching Agent on Morphological and Physical Properties of Poly(Butylene succinate) Foams

To enhance a viscosity of poly(butylene succinate) (PBS), a crosslinking agent (i.e. dicumyl peroxide, DCP) or branching agent (i.e. Desmodur (R) N3300, N3300) was incorporated with various amount ranging from 0 to 4 phr via an internal mixer. The thermal transition, rheological properties (e.g. storage modulus, loss modulus, and complex viscosity) and gel content of the compound were determined via differential scanning calorimeter, rheometer, and gel content measurement, respectively. The results revealed that less degree of crystallinity, higher viscosity and more crosslinked structure were detected as increasing amount of DCP and N3300. Subsequently, a compression moulding technique was used to prepare PBS foam with a chemical blowing agent, i.e. azodicarbonamide (ADC). Scanning Electron Microscopy was acquired to examine cell size, cell size distribution, cell structure, and cell density. Besides, physical properties, e.g. foam density and physical appearance, were investigated. The results indicate that the degree of crystallinity, viscosity, and crosslinked structure affect the morphological and physical properties of PBS foams, i.e. greater viscosity and crosslinked structure causing obstacle for cell growth, and less degree of crystallinity allowing easier cell nucleation and cell growth.