Mapossa Antonio Benjamim, Dos Anjos Erick Gabriel Ribeiro, Sundararaj Uttandaraman
Department of Chemical and Petroleum Engineering, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada.
Materials (Basel). 2024 Sep 16;17(18):4553. doi: 10.3390/ma17184553.
This study investigates the effects of inorganic flame retardants, zinc borate, and magnesium hydroxide, on the thermal, morphological, flame retardancy, and mechanical properties of polypropylene (PP)/calcium carbonate composites for potential construction industry applications. Polypropylene/calcium carbonate (50 wt.%) composites containing 5 and 10 wt.% flame retardants were prepared using a batch mixer, followed by compression moulding. The results demonstrated enhanced thermal stability, with the highest char residue reaching 47.2% for polypropylene/calcium carbonate/zinc borate (10 wt.%)/magnesium hydroxide (10 wt.%) composite, a notably strong outcome. Additionally, the composite exhibited an elevated limited oxygen index (LOI) of 29.4%, indicating a synergistic effect between zinc borate and magnesium hydroxide. The proposed flame retardancy mechanism suggests that the flammability performance is driven by the interaction between the flame retardants within the polypropylene/calcium carbonate matrix. Magnesium hydroxide contributes to smoke suppression by releasing water, while zinc borate forms a protective glassy foam that covers the burning surface, promoting char formation and acting as a physical barrier to heat transmission and fire spread. Scanning electron microscopy confirmed good dispersion of the additives alongside calcium carbonate within the polymer matrix. Despite the addition of up to 10 wt.% flame retardants, the composites maintained high-notched impact strength.
本研究考察了无机阻燃剂硼酸锌和氢氧化镁对用于潜在建筑行业应用的聚丙烯（PP）/碳酸钙复合材料的热性能、形态、阻燃性和力学性能的影响。使用间歇式混合器制备了含有5 wt.%和10 wt.%阻燃剂的聚丙烯/碳酸钙（50 wt.%）复合材料，随后进行模压成型。结果表明，热稳定性增强，聚丙烯/碳酸钙/硼酸锌（10 wt.%）/氢氧化镁（10 wt.%）复合材料的最高残炭率达到47.2%，这是一个非常显著的结果。此外，该复合材料的极限氧指数（LOI）提高到29.4%，表明硼酸锌和氢氧化镁之间存在协同效应。所提出的阻燃机理表明，聚丙烯/碳酸钙基体中的阻燃剂之间的相互作用驱动了燃烧性能。氢氧化镁通过释放水分有助于抑制烟雾，而硼酸锌形成覆盖燃烧表面的保护性玻璃状泡沫，促进炭的形成，并作为热传递和火灾蔓延的物理屏障。扫描电子显微镜证实了添加剂与碳酸钙在聚合物基体中的良好分散。尽管添加了高达10 wt.%的阻燃剂，复合材料仍保持了较高的缺口冲击强度。
