Effect of oligolactic acid stereocomplex microplates as rapid crystallization nucleating agents on the properties of poly(L‐lactic acid)

Abstract

AbstractAn efficient and scalable method to prepare oligolactic acid stereocomplex microplates (SC‐OLA‐MPs) is developed. Oligolactic acid was firstly synthesized via the melt polycondensation of lactic acid. Then, the oligo (L‐lactic acid) and oligo (D‐lactic acid) were crystallized with a mixture of dichloromethane and acetone, and consequently the stereocomplex microparticles were obtained in the form of circular microplates with a diameter of approximately 2 μm. As an eco‐friendly nucleating agent, SC‐OLA‐MPs were introduced into poly (L‐lactic acid) (PLLA) via melt blending. The nonisothermal and isothermal crystallization of the SC‐OLA‐MPs/PLLA composites were investigated, and the crystal morphology and heterogeneous nucleation phenomena during the isothermal crystallization process were photographed with POM. SC‐OLA‐MPs show excellent nucleating effects on PLLA crystallization. With the incorporation of 10% SC‐OLA‐MPs, the crystallization half‐time of the SC‐OLA‐MPs/PLLA composite decreased from 7.18 to 0.45 min at 100°C, compared to the neat PLLA. Through a short‐time molding procedure, the thermal deformation temperature of PLLA is improved by the addition of SC‐OLA‐MPs.Highlights Polylactic acid stereocomplex microplates were fabricated by solution crystallization. This method is easy and scalable. This microplate is an effective nucleating agent for PLLA.