界面成炭实现玻纤增强尼龙6高效阻燃研究

Wick effect is the main reason leading difficult flame resistance of glass fiber (GF) reinforced polymers.In this project,with further investigation of physical chemistry mechanisms, a novel interfacial charring flame resistance is designed compared with the traditional bulk method by adding high loading flame retardant in polymer matrix.Based on the scientific principle that wick effect is related to the adsorption,wetting,and flow of polymer melt on GF surface, a reactive charring catalyst (organic phosphorus flame retardant)will be grafted to the GF surface through the combination of coupling agent as a medium. This flame retardant can catalyze the interfacial resin into char in combustion high temperature,thus endowing GF with coarse and inert surface (replacing original polar and smooth surface), which can effectively restrict the interfacial wetting and flow of polymer melt,and block the thermodynamics and dynamic impact factors causing the wick effect.Additionally,the synergistic flame resistance mode combining bulk and interfacial one will be explored.This mode can realize the differentia distribution of the flame retardant elements,i.e.,high loading or efficient flame retardant distributed in interface where wick effect occurs, but low content or common flame retardant in bulk resin.By this way,the goals of ecnomical, reasonable and efficient use of flame retardants can be realized. Meanwhile, the organization of GF surface by grafting the interfacial flame retardant will improve the system compatibility,thus enhancing the mechanical properties of the composites.

烛芯效应是玻纤增强聚合物材料难阻燃的主要原因。项目拟对玻纤引发尼龙烛芯效应物理化学机制深入研究基础上，突破传统的阻燃剂本体添加方法，设计一种新颖的界面成炭阻燃模式来实现玻纤增强尼龙体系高效阻燃。基于烛芯效应本质为聚合物熔体浸润玻纤表面后向火源定向流动这一原理，通过偶联剂桥联实现反应型成炭催化剂（有机磷阻燃剂）在玻纤表面接枝，利用树脂燃烧高温下阻燃剂对尼龙6催化成炭作用在玻纤原有光滑、极性表面快速形成粗糙和惰性膨胀炭层，从而有效抑制聚合物熔体界面浸润和流动，阻断引发烛芯效应的热力学和动力学因素。探索界面成炭与阻燃剂本体添加结合的协同阻燃模式，实现阻燃剂从界面到本体差异化分布，即在烛芯效应发生，燃烧剧烈的界面区域配置高剂量或高效型阻燃剂；本体树脂区则配置低剂量或普通型阻燃剂，使阻燃剂使用经济、合理、高效化。另外，界面阻燃剂接枝也可使玻纤表面有机化，进而有效改善体系相容性，提高复合材料力学性能。

针对玻纤增强工程塑料PA6“烛芯效应”引起的阻燃技术难题及传统阻燃技术在解决无卤阻燃玻纤增强聚合物上的局限性，提出了一种新的阻燃模式—界面阻燃模式。传统的本体阻燃模式阻燃剂的添加量较高且均匀地分布在复合材料基体中。而界面阻燃模式是将低含量的阻燃剂集中（物理富集和化学接枝）分布在“烛芯效应”最显著的玻纤和树脂界面上，强化其界面阻燃性。所制备的界面阻燃玻纤增强尼龙6（GGF/PA6）较普通玻纤增强尼龙6（GGF/PA6）水平燃烧速率大幅降低，在界面燃烧过程中，形成的连续炭层包裹了玻纤的表面使其表面的粗糙度增加并使玻纤的表面能下降，有效阻碍了PA6熔体在玻纤表面的流动、润湿和铺展，有效抑制了“烛芯效应”。同时阻燃剂接枝也使玻纤表面有机化，使复合材料相容性得到改善，有利于力学性能提高。另外探索界面成炭与阻燃剂本体添加结合的协同阻燃模式，考察了三聚氰胺聚磷酸盐MPP对原纤体系和DOPO接枝玻纤体系的影响，结果表明，在25%MPP的添加量下，原纤体系不能通过UL-94测试，而改性玻纤体系的则可达到UL-94V-0级别，从而为制备高性能无卤阻燃玻纤增强PA6提供了一种新技术和新方法。