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将稻壳用10%的盐酸处理后在600℃焚烧得到纯度为99.3%,比表面积为212g/cm2的SiO2,经硅烷偶联剂γ-氨丙基三乙氧基硅烷(KH550)改性后的SiO2为无定形态,尺寸在30~50nm。将改性后的稻壳SiO2与EP复合,对SiO2/EP纳米复合材料的热膨胀过程进行了详细的研究。结果表明:稻壳SiO2的加入,能有效降低SiO2/EP纳米复合材料的热分解性能,其降低量随稻壳SiO2含量增加而增加。纳米复合材料在玻璃态(30℃≤T≤140℃)以及在大于180℃的橡胶态,热膨胀系数随温度变化不大,而在玻璃态与橡胶态的过渡区,材料随温度升高出现收缩。进一步研究发现材料的热循环次数对纳米复合材料的热收缩现象影响较大,热循环次数的增加能消除降低材料在升温过程的中的收缩现象,并有效降低材料的热膨胀系数。
The rice husk was treated with 10% hydrochloric acid and then incinerated at 600 ° C to obtain SiO 2 having a purity of 99.3% and a specific surface area of 212 g / cm 2. After being modified with a silane coupling agent γ-aminopropyltriethoxysilane (KH550) Of SiO2 is amorphous, the size of 30 ~ 50nm. The modified rice hull SiO2 and EP composite, SiO2 / EP nanocomposites thermal expansion process were studied in detail. The results show that the addition of rice hull SiO2 can effectively reduce the thermal decomposition performance of SiO2 / EP nanocomposites, and the decrease of SiO2 increases with the increase of SiO2 content of rice hull. In the glassy state (30 ℃ ≤T≤140 ℃) and in the rubbery state of more than 180 ℃, the thermal expansion coefficient of nanocomposites does not change much with the temperature. In the transition zone between glassy state and rubbery state, the material shrinks with temperature . Further study found that the number of thermal cycles of the material has a significant effect on the thermal shrinkage of the nanocomposites. The increase of the number of thermal cycles can reduce the shrinkage of the material during the heating process and effectively reduce the thermal expansion coefficient of the material.