凝聚相结构调控的氢氧化镁复合阻燃剂研究

Magnesium hydroxide, an important mineral form of magnesium resources, can be used as a green flame retardant of polymers with condensed-phase strategies. However, its distinct disadvantages are strong surface polarity and high loading level, which are detrimental to the mechanical properties of polymer composites. Based on the condensed-phase flame retardant mechanism of charring process, a synergistic model consisting of a magnesium hydroxide core and a synergist shell is proposed to improve interfacial interaction between flame retardant particles and polymer matrix in this project. Firstly, this project plans to employ boron-based synergist as shell to significantly enhance fire retardancy and decrease total loading amount by controlling the shell components and nanostructures, which could promote the migration and self-assembly to fabricate compact char layer structures in condensed phase. Further, this project aims to examine the following issues: the influence of using various morphology magnesium hydroxide core on the coating property, the regulative mechanism of shell components and nanostructures, the migrating and charring process of magnesium hydroxide particles in polymer melts, and the fire retardancy of this condensed-phase structural control in typical organic polymers. This project is expected to reveal the mechanism of flame-retardant synergistic effect and condensed-phase structural regulation, which can provide a strong foundation for developing green flame retardants in future.

氢氧化镁是镁资源的一种重要的赋存形式，可作为绿色阻燃剂在聚合物凝聚相中发挥阻燃作用，但由于表面极性、阻燃填充量大等缺陷，导致添加后复合物的力学性能显著下降。因此本课题基于凝聚相炭层结构调控机理，提出了一种氢氧化镁-协效剂的核-壳结构阻燃模型以提高阻燃粒子分散相与聚合物体相的相互作用。研究拟首先采用硼系协效剂作为壳相，通过调变核-壳粒子的壳相组成和纳米结构控制氢氧化镁粒子在凝聚相中迁移和自组装形成高质量的炭层结构以增强阻燃性能,降低总阻燃填充量；进一步研究不同形态核相氢氧化镁对壳相包覆能力的影响关系、壳相组成和纳米结构的调控规律、氢氧化镁粒子在聚合物体相中迁移结炭规律以及典型有机聚合物阻燃性能评价。可望揭示凝聚相炭层结构调控和增效阻燃的本质，为设计开发新型的绿色阻燃体系提供理论依据和应用基础。

氢氧化镁是镁资源的一种重要的赋存形式，可作为绿色阻燃剂在聚合物凝聚相中发挥阻燃作用，但由于表面极性、阻燃填充量大等缺陷，导致添加后复合物的力学性能显著下降。因此本课题基于凝聚相炭层结构调控机理，提出了一种氢氧化镁-协效剂的核-壳结构阻燃模型以提高阻燃粒子分散相与聚合物体相的相互作用。首先采用硼酸锌效剂作为壳相，通过调变核-壳粒子的壳相组成和纳米结构控制氢氧化镁粒子在凝聚相中迁移和自组装形成高质量的炭层结构以增强阻燃性能,降低总阻燃填充量；进一步研究了不同形态核相氢氧化镁对壳相包覆能力的影响关系、壳相组成和纳米结构的调控规律、氢氧化镁粒子在聚合物体相中迁移结炭规律以及典型有机聚合物（EVA、MVQ）阻燃性能评价。在此基础上，开发了一系列氢氧化镁@硼酸锌协效阻燃剂，并对其应用性能及增效机理展开研究，明确了 粒子迁移-阻燃微机理-凝聚相增强-阻燃效率提升 之间的关系。结果表明，对于凝聚相结构调控的阻燃体系，阻燃剂粒子的迁移能力和迁移行为会极大影响阻燃微机理，进而影响阻燃效率，与材料密度、界面粘度、表面能等因素有较大关系。本项目尽管仅就个别体系开展研究，其结果为设计开发新型的绿色阻燃体系提供理论依据和应用基础，对其它成分绿色无卤阻燃剂的开发也有借鉴意义。项目资助发表论文4篇，待发表1篇。培养硕士生3名，其中2名已经取得硕士学位，1名在读。项目批准经费25万元，支出18.09万元，各项支出基本与预算相符。剩余经费6.91万元，计划用于本项目研究后续支出。