含磷丙烯酸树脂的制备及其阻燃性能研究

Preparation of Phosphorus-Containing Poly-Acrylate Resins and their Flame Resistant Properties

采用甲基丙烯酸羟乙酯与五氧化二磷制备含磷单体—甲基丙烯酸羟乙酯磷酸酯(PMOE),并用于合成含磷丙烯酸乳液。研究含磷单体含量对乳液聚合过程稳定性及其树脂阻燃性能的影响。采用红外光谱(FTIR)分析含磷丙烯酸乳液的化学组成;通过热重分析(TGA)、极限氧指数(LOI)和UL-94方法测试含磷丙烯酸树脂的热稳定性和阻燃性能,并利用扫描电镜(SEM)观察含磷丙烯酸树脂残炭微观形貌。实验结果表明:当乳液体系中含磷单体的含量低于30%(wt)时,可以制备得到具有高单体转化率、低凝胶率且储存稳定良好的含磷丙烯酸乳液。随着含磷单体的提高,树脂的成碳率增大,LOI值提高,阻燃性能也得到提高。当含磷单体的用量为30%(wt)时,改性树脂的LOI值可以达到29.5%,并能通过UL-94测试的V-0级别,700℃下的成碳率可达54%(wt)。通过对树脂残炭的微观形貌分析,证明磷元素在丙烯酸树脂体系中主要起到凝聚相阻燃作用。

Phosphorous(P)-containing phosphoric acid methacryloyloxyethyl ester (PMOE) was synthesized with β-hydroxyethyl methacrylate (HEMA) and phosphorus pentoxide (P2O5), which was used to prepare P-containing poly-acrylate emulsion. The effects of PMOE content on polymerization stability and resin flame retardancy were studied. The chemical composition of the prepared P-containing poly-acrylate (PA) emulsion was characterized by FTIR, while the thermal stability and flame retardancy of the prepared P-containing PA resin was measured by TGA, LOI and UL-94 test, and the micro-morphology of the char residue from theP-containing PA resin was observed by SEM. The results show that P-containing PA emulsion with highmonomer conversion, low gelation and good storage stability can be obtained when the P-containing monomercontent is lower than 30%(wt). Char yield and LOI increase when the content of P-containing monomerincreases, which results in better flame retardancy. When the P-containing monomer content is 30 %(wt), LOIof the resin is 29.5%, and the char yield is 54 %(wt) at 700℃. The resin can pass the V-0 level of the UL-94 test.SEM results indicate that phosphorous shows a condensed-phase flame retardant effect.