Influence of branching on the mechanical, rheological and crystallization properties of poly(butylene adipate-co-terephthalate)

Biodegradable poly(butylene adipate-co-terephthalate) (PBAT) was branched by dicumyl peroxide. Comparing with the linear PBAT, the branched PBATs characterized significantly improved strain hardening ability leading to a higher tensile strength. Rheological results showed that the branched PBAT samples displayed high elastic modulus and complex viscosity. Differential scanning calorimetry analysis indicated the double effect of branched structure on the crystallization which can promote the nucleation and also hinder the chains diffusion, ultimately, resulting in reduction in △Hc. The higher crystallization temperature was obtained which was meaningful to enhance the melt strength during the cooling process. The Mo method successfully described the nonisothermal melt crystallization behavior of linear and branched PBATs. In general, the total crystallization rate was controlled by the crystal growth rate. The activation energy of the branched PBAT samples as calculated based on Friedman equation was universally larger than the one of linear PBAT.