以经过表面胺基改性后的纳米SiO2为核心,通过重复迈克尔加成反应和酰胺化反应在其表面接上树枝型结构,合成了SiO2锚合聚酰胺-胺型(PAMAM)树枝状大分子。然后将不同代数的树枝化SiO2加入到十二内酰胺开环聚合反应中,以原位聚合的方法制备了一系列的PA12/纳米SiO2复合材料。研究了SiO2接枝率、加入量等条件对复合材料力学性能、热性能和结晶形态的影响。结果表明,二氧化硅表面树枝状大分子的接枝率随着代数的增加而提高,但实际接枝率低于理论值。PA12/纳米SiO2复合材料的缺口冲击强度较PA12的高,拉伸强度变化不大。
Using aminosurface-modified nano SiO2 as multifunctional reactant, polyamidoamine dendrimer (PAMAM) was propagated on silica surface by repeating michael addition and amidation reactions, and three generations branch-shaped silicas were obtained. A series of Nylon12/nano silica composites were prepared by in-situ ring-opening polymerization by using different generations of branch-shaped silicas and laurolactam. The effect of graft ratio and amount of SiO2 on mechanical properties, thermal properties, crystal morphology, relative viscosity and of composites were studied in detail. The results show that graft ratio of PAMAM on silica surface increases with increasing generations, but the measured ratio is smaller than theoretical value. The notched impact strength of the composite is higher than that of Nylon12, while there is no significant change in tensile strength.