Thermal and mechanical properties of poly(lactic acid)/poly(butylene adipate-co-terephthalate)/calcium carbonate composite with single continuous morphology

Poly(lactic acid)/poly(butylene adipate-co-terephthalate) with a content ratio of 90/10, and its calcium carbonate (CaCO3) composites with nano- and micro-sized particles were prepared by melt mixing. The dependence of thermal and mechanical properties of the composites on the particle size and addition content of the CaCO3 filler was investigated. The composite containing five parts micro-sized filler (abbreviated as (LBC)-L-90-B-10-C-5m, similarly hereinafter) exhibited alpha and alpha & PRIME; crystallines on cooling as (LB)-L-90-B-10 without fillers. (LBC)-L-90-B-10-C-11m and (LBC)-L-90-B-10-C-11n5m exhibited only alpha & PRIME; crystalline, and the others exhibited no discernible crystalline. Jeziorny method showed that the crystallization mode of poly(lactic acid) chains in different composites was close, and Mo method showed that the crystal growth mode in (LBC)-L-90-B-10-C-11n5m was different from others. Changes in thermal and mechanical properties were attributed to the overall connection strength which was dependent on the particle size and addition content of the CaCO3 filler. From the perspective of industrialization, (LBC)-L-90-B-10-C-5n11m was preferred.