Toughening poly(lactic acid) by CaCO3 treated with waste lower purity dimer fatty acid

With the growing emphasis on environmental conservation, the utilization of biomass resources has garnered increasing attention. Dimer acid, derived from vegetable oils, serves as a high-quality chemical raw material while the waste lower purity dimer acid (WLPDA) will result in environmental pollution and resource wastage. In this work, WLPDA was employed as a surface modifier for calcium carbonate (CaCO3) particles with the aim of toughening of poly(lactic acid) (PLA). The addition of WLPDA demonstrates excellent modifying effects on CaCO3, achieving an activation index of 100% and an increased contact angle from 14 degrees to around 120 degrees. Furthermore, the PLA/WLPDA modified CaCO3 (D-CaCO3) composites exhibit noticeably toughening effects, with a maximum increase of 87% in impact strength. The improvement can be attributed to the favorable plastic deformation of interparticle ligaments following particle-matrix debonding and the long aliphatic chains of WLPDA. This research highlights the viability of replacing stearic acid with WLPDA as the surface modifier for inorganic fillers, providing a promising alternative for the toughening modification of polymers. Additionally, it presents a novel approach for the comprehensive utilization of dimer acid biomass resources.