Use of a chain extender as a dispersing agent of the CaCO 3 into PBAT matrix

Abstract

This paper investigates the effect of the incorporation of chain extender on the poly(butylene adipate-co-terephthalate) (PBAT) and their mixture with calcium carbonate (CaCO₃) composites. Chain extender (ADR) was used to enhance the compatibility between PBAT and CaCO₃, which have poor interfacial adhesion. Mechanical, thermal, and morphological properties of PBAT, PBAT/chain extender, and their composites were studied. The incorporation of the chain extender enhanced Young’s modulus and elongation at break of the neat PBAT, which is an indicator of the interaction between both materials. These results were confirmed by ¹H NMR and ¹³C NMR (proton – hydrogen and carbon nuclear magnetic resonance, respectively). The chain extender acted by dispersing the CaCO₃ particles; however, with an increase in the filler content, there is a decrease in the mechanical properties. Thermogravimetric analysis showed that chain extender has no influence on neat PBAT thermal behavior and their composites containing CaCO₃. Differential scanning calorimetric analysis showed a decrease in crystallinity values of the PBAT and its composites, which is due to the physical impediment in the organization of polymer chains. Photomicrographs, obtained by scanning electron microscopy, showed that chain extender does not influence PBAT morphology. However, in the composites, chain extender enhanced the dispersion on CaCO₃ particles.