Huang Weijiang, Wang Kui, Tu Chunyun, Xu Xiaolu, Tian Qin, Ma Chao, Fu Qiuping, Yan Wei
School of Chemistry and Materials Engineering, Guiyang University, Guiyang 550005, China.
National Engineering Research Center for Compounding and Modification of Polymer Materials, Guiyang 550014, China.
Polymers (Basel). 2022 Jun 11;14(12):2372. doi: 10.3390/polym14122372.
Polypropylene (PP), as a general thermoplastic polymer, is broadly used in different fields. However, the high flammability, melt dripping and poor mechanical properties of PP are a constraint to the expansion of its applications. In this paper, PP composites containing a combination of a phenethyl-bridged DOPO derivative (PN-DOPO) and organic montmorillonite (OMMT) were prepared via melt blending. The synergistic effects of PN-DOPO and OMMT on the flame retardancy, thermal stability and mechanical properties of PP composites were investigated systematically. The results showed that 20 wt% addition of PN-DOPO with OMMT improved the flame retardancy of PP composites. In particular, the introduction of 17 wt% PN-DOPO and 3 wt% OMMT increased the LOI values of the PP matrix from 17.2% to 23.6%, and the sample reached the V-0 level and reduced the heat release rate and total heat release. TGA indicated that OMMT could improve the thermal stability of the PP/PN-DOPO blends and promote the char residues of PP systems. Rheological behaviour showed a higher storage modulus, loss modulus and complex viscosity of PP/PN-DOPO/OMMT composites, suggesting a more effective network structure. In addition, the tensile strength, flexural properties and impact strength of the PP/PN-DOPO/OMMT composites actually increased for a good dispersion effect. Combined with the char layer analysis, the introduction of OMMT promoted more continuous and compact structural layers containing an aluminium-silicon barrier and phosphorus-containing carbonaceous char in the condensed phase. OMMT can improve the flame retardancy, thermal stability and mechanical properties of PP, and, thus, PN-DOPO/OMMT blends can serve as an efficient synergistic system for flame-retarded PP composites.
聚丙烯（PP）作为一种通用热塑性聚合物，广泛应用于不同领域。然而，PP的高易燃性、熔体滴落和较差的机械性能限制了其应用的扩展。本文通过熔融共混制备了含有苯乙基桥联的DOPO衍生物（PN-DOPO）和有机蒙脱土（OMMT）组合的PP复合材料。系统研究了PN-DOPO和OMMT对PP复合材料阻燃性、热稳定性和机械性能的协同作用。结果表明，添加20 wt%的PN-DOPO与OMMT可提高PP复合材料的阻燃性。特别是，引入17 wt%的PN-DOPO和3 wt%的OMMT使PP基体的极限氧指数（LOI）值从17.2%提高到23.6%，样品达到V-0级，并降低了热释放速率和总热释放量。热重分析（TGA）表明，OMMT可提高PP/PN-DOPO共混物的热稳定性，并促进PP体系的残炭率。流变行为表明，PP/PN-DOPO/OMMT复合材料具有更高的储能模量、损耗模量和复数粘度，表明形成了更有效的网络结构。此外，由于良好的分散效果，PP/PN-DOPO/OMMT复合材料的拉伸强度、弯曲性能和冲击强度实际上有所提高。结合炭层分析，OMMT的引入促进了凝聚相中含有铝硅阻挡层和含磷碳质炭的更连续、致密的结构层的形成。OMMT可提高PP的阻燃性、热稳定性和机械性能，因此，PN-DOPO/OMMT共混物可作为PP阻燃复合材料的高效协同体系。
