Enhanced poly(butylene adipate‐<i>co</i>‐terephthalate) composite films reinforced with nano‐calcium carbonate modified by a comb‐like polyacrylic superdispersant

Abstract A comb‐like polyacrylic superdispersant (CPS) consisting of polyacrylic acid‐ co ‐poly(isobutyl alcohol polyoxyethylene ether) (PBAT) was synthesized as a dispersant for preparing nano‐calcium carbonate/PBAT (nano‐CaCO 3 /PBAT) composite through internal mixing. Chemical structure analysis revealed that CPS adsorbed onto the surface of nano‐CaCO 3 via coordination between carboxyl groups and calcium ions, effectively dispersing particles using a comb‐shaped side chain and electrostatic repulsion. This improved compatibility between nano‐CaCO 3 and PBAT resulted in enhanced crystallinity, tensile stress, and elongation at break. By incorporating only 0.4 wt% CPS into 10 wt% nano‐CaCO 3 (based on PBAT weight), the dispersion of nano‐CaCO 3 was significantly improved, leading to a superior two‐phase interface in the composite material. Consequently (in the film's machine direction), elongation at break increased from 882 ± 49% to 1047 ± 31%, while tensile strength increased from 22.10 ± 2.06 MPa to 26.70 ± 1.14 MPa. These findings facilitate the production of high‐performance PBAT composites suitable for blow molding into biodegradable films. Highlights Comb‐like polyacrylic superdispersant synthesized by aqueous polymerization. Nano‐CaCO 3 modified via the adsorption and dispersion of CPS. Stress and elongation of PBAT composite reinforced by CPS‐modified nano‐CaCO 3 . CPS‐modified nano‐CaCO 3 /PBAT composite films processed through blow molding. Enhancement by coordination, hydrogen‐bond action, and microphase separation.