Preparation and Properties of Bio-Based Flame Retardant L-APP/Poly(L-lactic acid) Composites

Poly(L-lactic acid) (PLLA) is a thermoplastic material with complete degradability, high biocompatibility and excellent mechanical properties. It can replace petroleum-based polymers are currently being used in the fields of packaging, agriculture, textiles, medical and so on. However, PLLA’s extremely flammability greatly limits its wider application. An bio-based flame retardant L-APP/PLLA composites was prepared by melt blending of the L-APP and PLLA. The morphology, impact properties, thermal properties and flame retardant properties of composites were investigated by field emission scanning electron microscope (SEM), impact tester, differential scanning calorimeter (DSC), thermogravimetric analyzer (TGA), limiting oxygen indexer (LOI) and horizontalvertical burning tester. The results showed that the degree of crystallization (Xc) and LOI of L-APP/PLLA composites increased as increasing of L-APP content. What’s more, the impact strength first increased and then decreased, the glass transition temperature (Tg) and melting temperature (Tm) do not changed significantly. The impact strength of composites was 9.1 kJ/m2 at a 5 wt% loading for L-APP, which was the highest level. When the content of L-APP was 20%, the LOI was 30.8%, the Xc was 42.3% and the UL-94 level was V-0. This research can promote the value-added utilization of lignin and the application of PLLA in the fields of flame retardant materials.