Influence of modified fiber–MHSH hybrids on fire hazards,combustion dynamics,and mechanical properties of flame-retarded poly(butylene succinate) composites

Environmental problems caused by polymers and polymers have historically dominated both academic and industrial attention. Sustainable biodegradable wood-plastic composites (WPCs) as an optimum can solve the environmentally critical problems caused by petroleum-based polymers. However, they are flammable, prone to fire accidents, and often have a contradiction between mechanical performance and flame-retardant properties, which limits their range of applications. Here, we reported a flame-retarded poly(butylene succinate) (PBS) WPC prepared with modified natural fiber-magnesium hydroxide sulfate whisker (MHSH) hybrids and intumescent flame retardant s (IFRs). The mechanical performance, flame-retardant properties , thermal stability, and actual fire simulation parameters of composites were investigated. Owing to the unique composition characteristics of modified cassava dregs-MHSH hybrids, the mechanical properties (70P/23I/5C/2M, flexural strength was 39.2 ± 1.960/MPa, impact strength was 7.95 ± 0.3975/ KJ/m²]), flame retardant properties (70P/23I/5C/2M, the limiting oxygen index value was 39.6%, UL-94 was V0) and thermal stability of WPC have been improved. Thereby, the balance between mechanical performance and flame retardant properties of biocomposites has been achieved in the practical engineering requirements. Furthermore, cone calorimeter data indicated that modified cassava dregs–MHSH hybrids played a role in improving the fire safety of composites. The total heat release, total smoke produce, toxic gas release, and total oxygen consumed of 70P/23I/5C/2M were lowered compared with those of 70P/25I/5C. Dynamics analysis indicated that the addition of modified cassava dregs–MHSH hybrids increased the activation energy of composites. Based on the experimental and analyses data, especially the morphological characterization of char residue analysis, it illustrated that modified cassava dregs–MHSH hybrids have a reinforcement and flame-retardant effect. The combusted residue of the incorporated modified cassava dregs–MHSH hybrids could support the three-dimensional charred layer formed by the combustion products of the IFR and the PBS. Thus, the more stable three-dimensional charred layer could not only effectively reduce thermal conductivity of composites but also hinder the propagation of heat into the interior substrate, thereby improving the flame-retardant properties of the WPC. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48490.