粉煤灰空心微珠包覆纳米氢氧化镁复合材料的可控制备及填充尼龙6性能研究

Development of low cost, good comprehensive performance of polyamide 6 is of great significance to enlarge its application scope. Fly ash cenosphere particle is a kind of ideal polymer filler due to its low cost, good dispersibility and fluidity, no internal stress as a filler and non-toxic properties. However, fly ash cenosphere filling in polymer has many problems, such as low whiteness, high abrasion, poor compatibility and low flame retardant property. Nano-magnesium hydroxide has high whiteness, low mohs hardness, good flame retardant property.However it is difficult for nano-magnesium hydroxide to disperse in filling the polymer. This project amis to prepare controllable fly ash cenosphere coated with nano-magnesium hydroxide composite through heterogeneous nucleation method. Then the properties of the composite filling in polyamide 6 will be studied. To achieve controllable fabrication and activity optimization, the impact of different factors on the distribution, shape and surface specific area of composite material and properties in filling polyamide 6 will be investigated. Based on the analysis of the transfer of the main reactive species and the change of intermediate products and surface/interface of PA6 composites subjected to stress and heat, the structure-function relationship between composite structure and properties and assist effective flame retardant and strengthening mechanism of PA6 filled with fly ash cenosphere coated with nano-magnesium hydroxide will be discussed.It will provide theoretical basis and technology support for properties control of industrial polymer.

开发经济性、综合性能良好的环保阻燃尼龙6复合材料，对于扩大其应用范围具有重要意义。粉煤灰空心微珠分散性与流动性好、无毒、作填料时没有引发内应力，是一种理想的聚合物填料，但是其填充聚合物白度低、磨耗高、相容性和阻燃性差；而纳米氢氧化镁具有白度高，莫氏硬度低、无卤、阻燃、抑烟的优点，然而其填充聚合物分散性差。鉴于此，本项目以空心微珠为载体，设计一种组分和微结构可控的空心微珠包覆纳米氢氧化镁复合材料，并对其填充尼龙6复合材料性能进行研究。通过研究制备过程中合成工艺对空心微珠包覆氢氧化镁复合材料形貌、比表面积及填充尼龙6复合材料性能的影响规律，实现复合粉体可控制备和性能优化的有效耦合。通过探究尼龙6复合材料受力和受热过程中表/界面变化和主要活性自由基转移过程以及中间产物变化等，揭示复合材料结构与性能之间的构效关系，阐明复合材料协效增强和阻燃尼龙6机理，为工业聚合物性能控制提供理论基础和技术支持。

以粉煤灰为原料，研究了工艺条件对粉煤灰基复合粉体制备的影响，优化了工艺条件，建立了工艺条件与粉煤灰基复合粉体白度、物化性能之间的关系，结果表明，最佳工艺条件为：包覆量为70%，包覆剂滴加速度为5 mL/min，溶液pH=10，反应温度为90 ℃，反应时间为90 min，粉煤灰空心微珠与水固液比为1:5。粉煤灰表面成功负载了纳米氢氧化镁、纳米氧化锌和纳米硅酸铝粒子，白度提高，比表面积增大，镁盐阴离子种类对粉煤灰基复合粉体形貌影响较大，以硫酸镁、氯化镁、硝酸镁和氢氧化钠反应可以得到粉煤灰负载纳米片状、球状、棒状粒子；复合粉体填充尼龙6应用试验结果表明：粉煤灰负载纳米氢氧化镁可以代替纳米氢氧化镁填充尼龙6，不但可以提高其力学性能和阻燃性能，而且可以改善纳米氢氧化镁填充尼龙6难分散的问题，粉煤灰负载纳米氧化锌和纳米硅酸铝填充尼龙6也可以提高尼龙6的力学性能；粉煤灰基复合粉体增强尼龙6机理为：粉煤灰表面粗糙度增大；阻燃机理为：粉煤灰及纳米粒子协效阻燃。此外，粉煤灰负载纳米氢氧化镁复合粉体还可以用于吸附废水中的重金属离子，性能优于粉煤灰原样和纳米氢氧化镁，可以解决纳米氢氧化镁吸附重金属离子回收难的问题和粉煤灰吸附性差的问题。