分子模拟硅灰石与硅烷作用机制及改性粉体填充尼龙6性能

Molecular simulation of the interaction mechanism between wollastonite and silane and the properties of modified powder filled nylon 6

  • 摘要: 通过采用硅烷对硅灰石进行干法改性优化硅灰石物化性能,探究了改性温度、时间、硅烷用量对改性效果的影响。采用红外光谱对改性前后硅灰石粉体表面官能团进行表征。分别将未改性硅灰石原样与改性粉体填充尼龙6制备复合材料,对复合材料的冲击强度、拉伸强度、弯曲强度、弯曲模量、热变形温度等指标进行测试。使用分子模拟分析了硅烷SCA1113 (3-氨丙基三乙氧基硅烷)改性硅灰石的微观机制。结果表明:改性温度80 ℃,改性时间20min,硅烷用量0.8%为优化工艺条件;未改性硅灰石填充尼龙6样品较尼龙6纯样刚性提高但降低韧性,而改性后的硅灰石填充尼龙6可以同时提高尼龙6材料的刚性与韧性;硅烷SCA1113改性硅灰石时其反应性不来自于硅灰石晶体内部,晶面(100)最具反应性,硅烷SCA1113与硅灰石表面吸附为化学吸附,形成了Si-O-Ca键。

     

    Abstract: The physical and chemical properties of wollastonite were optimized through dry modification with silane, and the effects of modification temperature, time, and silane dosage on the modification effect of wollastonite were explored. Infrared spectroscopy was used to characterize the surface functional groups of wollastonite and modified wollastonite. PA6 composite materials were prepared by filling wollastonite and modified wollastonite powder in polyamide 6 (PA 6), and the impact strength, tensile strength, flexural strength, and flexural modulus of the composite materials were tested. The microscopic mechanism of wollastonite modified by SCA1113 (3-Aminopropyltriethoxysilane)was analyzed using molecular simulation. The results show that the optimize modification process conditions of wollastonite are the modification temperature of 80°, the modification time of 20 minutes, and the silane dosage of 0.8%. Unmodified wollastonite filled nylon 6 can improve the rigidity of the composite material but reduce its toughness compared to pure nylon 6 samples, while modified wollastonite filled nylon 6 can simultaneously improve the rigidity and toughness of the material; When silane SCA1113 modifies wollastonite, its reactivity does not come from inside the wollastonite crystal, and the crystal surface (100) is the most reactive, and silane SCA1113 and wollastonite surface are adsorbed to form Si-O-Ca bond.

     

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