Investigation of the Flammability and Thermal Stability of Halogen-Free Intumescent System in Biopolymer Composites Containing Biobased Carbonization Agent and Mechanism of Their Char Formation
Investigation of the Flammability and Thermal Stability of Halogen-Free Intumescent System in Biopolymer Composites Containing Biobased Carbonization Agent and Mechanism of Their Char Formation
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DOI：
10.3390/polym11010048
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发表时间：
2019-01-01
期刊：
影响因子：
5
通讯作者：
Seide, Gunnar
中科院分区：
文献类型：
--
作者：
Maqsood, Muhammad;Seide, Gunnar
淀粉是一种具有天然成炭能力的多元化合物，是膨胀体系中理想的成炭剂。淀粉的这种炭化能力，如果伴随着酸性源，可以产生有效的膨胀型阻燃剂（IFR）系统，但在IFR系统中的淀粉基复合材料的性能还没有被详细测试。在这里，我们描述了一个基于聚乳酸IFR系统组成的聚磷酸铵（APP）作为酸源和玉米淀粉作为碳源。我们通过熔融配混制备不同的配方，然后通过热压成型为片材。采用热重分析和扫描电镜分别研究了复合材料的热行为和表面形貌。我们还进行了极限氧指数（LOI），UL-94和锥形量热法测试，以表征阻燃性能。锥形量热法显示，与纯PLA相比，IFR复合材料的峰值热释放速率降低了66%，并且通过相对于样品的初始质量留下43%的残余质量来指示膨胀型结构的发展。并对成炭机理进行了讨论。
Starch, being a polyhydric compound with its natural charring ability, is an ideal candidate to serve as a carbonization agent in an intumescent system. This charring ability of starch, if accompanied by an acidic source, can generate an effective intumescent flame retardant (IFR) system, but the performance of starch-based composites in an IFR system has not been tested in detail. Here, we describe a PLA-based IFR system consisting of ammonium polyphosphate (APP) as acidic source and cornstarch as carbon source. We prepared different formulations by melt compounding followed by molding into sheets by hot pressing. The thermal behavior and surface morphology of the composites was investigated by thermogravimetric analysis and scanning electron microscopy respectively. We also conducted limiting oxygen index (LOI), UL-94, and cone calorimetry tests to characterize the flame-retardant properties. Cone calorimetry revealed a 66% reduction in the peak heat release rate of the IFR composites compared to pure PLA and indicated the development of an intumescent structure by leaving a residual mass of 43% relative to the initial mass of the sample. A mechanism of char formation has also been discussed in detail.