Control of Material Properties by Coating of Fine Particles with High-Speed Rotational Impact Blending

首先，通过高速旋转冲击共混和通过在砂浆中手动混合，用红色氧化铁的细颜料颗粒涂覆粗白色聚乙烯颗粒，并且研究细颗粒的混合比、处理时间、旋转速度和粗颗粒的平均直径相对于混合程度的影响。结果发现，在混合比小于100%的情况下，混合度随着处理时间的增加而增加，但通过旋转冲击使混合比超过100%的比例降低，并且由于混合度的增加，亮度降低至低于手动混合，但在冲击共混期间几乎保持不变。这意味着颗粒的亮度在非常短的混合时间内达到稳定状态，导致当使用旋转冲击式混合器时，对于相同的亮度效果，细颗粒的量减少。采用旋转冲击共混法，以二氧化钛粉体为细颗粒，包覆尼龙和聚乙烯粗颗粒。考察了包覆率和粒径对紫外衰减效果的影响。发现UV防护的有效性通过降低涂覆比率而增加，因为这导致形成较低水平的表面附聚物。用细二氧化钛涂覆大聚合物颗粒的另一个优点是本体分散的改善，这导致最佳的UV保护。

First, coarse white polyethylene particles were coated by fine pigment particles of red iron oxide by high-speed rotational impact blending and by hand mixing in a mortar, and the effects of the mixing ratio of fine particles, the treatment time, the rotational speed and the mean diameter of coarse particles were investigated with respect to the degree of mixing. It was found that the degree of mixing increased with the treatment time at a mixing ratio of less than 100%, but decreased the ratio of over 100% by rotational impact, and that the lightness decreased to lower than that by hand mixing due to the increased degree of mixing, but remained almost constant during the impact blending. This means that the lightness of particles reached a steady state in a very short mixing time, resulting in the reduction of the amount of fine particles for the same lightness effect when using the rotational impact blender. Then, titanium dioxide powder was used as the fine particles to coat coarse nylon and polyethylene particles by the rotational impact blending. The effects of coating ratio and size of the coarse particles were investigated on the effectiveness of UV attenuation. The effectiveness of UV protection was found to be increased by decreasing the coating ratio, as this led to a lower level of surface agglomerates being formed. A further advantage of coating large polymer particles with fine titanium dioxide was an improvement in the bulk dispersion, which resulted in optimum UV protection.