反应型阻燃剂双(2-羧基乙基)膦酸的合成及在尼龙66上的阻燃应用

Study on the Synthesis of Reactive Flame Retardant Bis (2-carboxyethyl) Phosphinic Acid and Its Flame Retarding Application in Nylon 66

以次磷酸、原甲酸三甲酯、丙烯腈等为原料合成了一种新的尼龙66阻燃剂双(2-羧基乙基)膦酸。应用傅里叶变换红外光谱仪(FTIR)、X射线能谱分析(EDS)、差示扫描量热分析(DSC)和热重分析仪(TGA)分别表征双(2-羧基乙基)膦酸的化学结构、元素组成和热稳定性,并将双(2-羧基乙基)膦酸加入到尼龙66的反应体系中,制备了阻燃尼龙66。研究结果表明:通过控制反应温度、反应时间和反应物摩尔比,双(2-羧基乙基)膦酸产率可达到50.79%;合成的阻燃剂具有双(2-羧基乙基)膦酸的分子结构特征;双(2-羧基乙基)膦酸的起始分解温度200℃,低于尼龙66聚合反应温度,但作为预聚体添加到尼龙66中,满足尼龙66合成工艺;在800℃时残炭量为6.36%,说明双(2-羧基乙基)膦酸具有较好的成炭性;当双(2-羧基乙基)膦酸添加量为6%时,阻燃尼龙66的LOI值达到28.0%;当双(2-羧基乙基)膦酸添加量达4%或更高时,垂直燃烧性能达到V-0级别。

A novel flame retardant for nylon 66 bis （2-carboxyethyl）phosphinic acid was synthesized by hypophosphorous acid, trimethyl orthoformate and acrylonitrile etc. The chemical structure, elemental composition and thermostability were characterized by FTIR, EDS, TGA and DSC, respectively. Bis（2-carboxyethyl）phosphinic acid was added in the reaction system of nylon 66 to prepare flame retardant nylon 66. The results indicate that. the yield of bis（2-carboxyethyl）phosphinic acid can be up to 50. 79% by controlling the reaction temperature, reaction time and the molar ratios of the reactants. And the synthesized flame retardant has the molecular structure of bis （2-carboxyethyl）phosphinic acid. The initial decomposition temperature of bis （2-carboxyethyl）phosphinic acid is 200℃, lower than the polymerization reaction temperature of nylon 66. But, it can meet the requirement of the synthesis process of nylon 66 when it is added in nylon 66 as the prepolymer. The amount of char residue is 6. 36% at 800℃. This indicates bis（2-carboxyethyl）phosphinic acid has good char-forming ability.When the additive amount of bis（2-carboxyethyl）phosphinic acid is 6%, the LOI value of flame retardant nylon 66 reaches 28. 0%. When the additive amount is 4% or above, the vertical burning property can reach the level of Ⅴ-0.