The influence of double-layered distribution of fire retardants on the fire retardancy and mechanical properties of wood fiber polypropylene composites

摘要

Expandable graphite (EG) and ammonium polyphosphate (APP) distributed in different layer of wood fiber and polypropylene composites (WPPC) were prepared. The results of cone calorimetry showed that the layered distribution of EG and APP considerably improved the fire retardancy of the overall composites, and the char residue rate was 41.9%, which increased by 200% compared with that of single-layered WPPC. Moreover, a more firm and compact physical structure char in the base layer formed due to protection of EG in the surface layer. The flexural strength and modulus of double-layered WPPC also increased compared with these of the single-layered WPPC with EG. (C) 2020 Elsevier Ltd. All rights reserved.