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Keywords:

  • polypropylene;
  • modified ammonium polyphosphate;
  • mechanical properties;
  • flame retardance;
  • thermogravimetric analysis

Abstract

In this article, the influence of ammonium polyphosphate (APP) and ammonium polyphosphate modified with 3-(Methylacryloxyl) propyltrimethoxy silane (M-APP) on mechanical properties, flame retardancy, and thermal degradation of wood flour–polypropylene composites (WF/PP composites) have been investigated. Polypropylene grafted with m-isopropenyl-α,α-dimethylbenzyl-isocyanate (m-TMI-g-PP) was used to improve the adhesion of WF/PP composites. APP and M-APP were used as flame retardants. The experimental results demonstrated that addition of M-APP obviously enhanced mechanical properties of WF/PP composites. According to cone calorimetry results, M-APP is also an effective flame retardant for WF/PP composites, compared to that of APP. It was also found that M-APP decreased the 1% weight loss temperature and increased char residue. The thermal degradation of wood flour based upon the first peak temperature of wood decreased from 329.3 to 322.9°C and the thermal degradation of PP based upon the second peak temperature of PP improve from 518.0 to 519.6°C, when M-APP was added to the WF/PP composites. From SEM results the char layer of the 25% M-APP systems is much more intumescent than that of the 25% APP systems, indicating that 3-(Methylacryloxyl) propyltrimethoxy silane can improve the char-forming ability of WF/PP composites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011