吹熄阻燃环氧树脂机理研究

A new type of phosphorus-containing polyhedral oligomeric silsesquioxane (DOPO-POSS) is synthesized successfully. It is found that DOPO-POSS in very low content can flame retard the epoxy resin (EP) effectively, moreover, EP/DOPO-POSS composites exhibit a blowing-out effect through vigorous emission of pyrolytic gases. The relationships between the change of pyrolytic gases (composition, concentration, and emission speed) and blowing-out effect are investigated to reveal the flame retardancy mechanisms of DOPO-POSS in the gas phase. The structures of epoxy resin, curing agent, and flame retardant, which could influence the blowing-out effect of EP composites, is investigated to understand the reasons of blowing-out effect. All of these researches could help us to found the physical model and chemical model, which could explain the mechanism of the blowing-out effect and make us could control the blowing-out effect of EP composites. The research of mechanism of blowing-out effect possesses profound meaning and offers us a new method and theoretical foundation to product some effective flame retardants for epoxy resins.

前期工作中成功合成了含有DOPO基团的笼型低聚硅倍半氧烷(DOPO-POSS)，而且发现DOPO-POSS在很低含量时即能有效的阻燃环氧树脂，并呈现独特的"吹熄"阻燃现象。本项目通过研究DOPO-POSS对"吹熄"阻燃环氧树脂气相产物成分、浓度、以及释放速度等影响揭示"吹熄"阻燃在气相中的作用机理；研究"吹熄"阻燃环氧树脂交联网络结构和分子结构（环氧树脂、固化剂和阻燃剂的分子结构）与"吹熄" 阻燃现象的关系，确定"吹熄"现象成因和影响因素，并以此为基础建立"吹熄"阻燃环氧树脂的物理、化学模型。然后最终揭示"吹熄"阻燃机理，并实现"吹熄"阻燃环氧树脂阻燃性能的可控性。研究"吹熄"阻燃环氧树脂的机理具有深远的意义，将为我们开发新型高效环氧树脂阻燃剂提供新的方法和理论基础。

项目通过研究DOPO-POSS阻燃环氧树脂时表现出的“吹熄”现象，第一次提出吹熄阻燃环氧树脂概念。将DOPO-POSS用于阻燃DGEBA/m-PDA、DGEBA/PA650、TGDDM/DDS等多种环氧树脂体系。同时还将DOPO与多种硅倍氧烷（OPS、OAPS、PPSQ）通过物理混合用于阻燃环氧树脂。通过对比不同配方吹熄阻燃效应的差异来逐步揭示“吹熄”阻燃机理。本项目研究设计并建立了两种实验方法，分别用于分析燃烧过程中环氧树脂样品不同时间和不同位置的炭层物理、化学结构的变化情况，以及环氧树脂在UL-94垂直燃烧过程中的凝聚相温度的变化情况，建立“吹熄”阻燃环氧树脂的物理、化学模型。根据吹熄阻燃机理对环氧树脂进行阻燃，得到了数个阻燃性能和综合性能优异的环氧树脂配方，这些配方中的硅、磷阻燃元素的含量明显低于目前已有商业化产品，具有很好的应用前景。