采用不同粒径亚微米镍粉与硅橡胶按质量比为2∶1,2.8∶1进行配料,经过特殊的制备方法,制备成镍/硅橡胶高分子复合材料,并主要研究了复合材料的压敏性能和介电性能.通过对材料做性能测试发现当用亚微米镍粉做导电填料时,复合材料具有优...采用不同粒径亚微米镍粉与硅橡胶按质量比为2∶1,2.8∶1进行配料,经过特殊的制备方法,制备成镍/硅橡胶高分子复合材料,并主要研究了复合材料的压敏性能和介电性能.通过对材料做性能测试发现当用亚微米镍粉做导电填料时,复合材料具有优异的压敏性能:当仅对材料施加一个200 k Pa压强时,质量比为2.8∶1的镍(400纳米填料)/硅橡胶复合材料的电导率变化了9个数量级.同时,材料的压敏性能会随着导电填料粒径的变化而发生变化.为了充分研究材料的电学性能,实验分别测量出在不同压强下材料的电导率、介电常数随频率的变化数据,研究发现:当频率和压强发生变化时,材料的电导率和介电常数也会发生变化,表现出不同的电荷输运机制.展开更多
With the help of the low-frequency internal friction method, we investigate the structural properties of polymer melts, such as amorphous polystyrene （PS）, poly（methyl methacrylate） （PMMA）, and semi-crystalline ...With the help of the low-frequency internal friction method, we investigate the structural properties of polymer melts, such as amorphous polystyrene （PS）, poly（methyl methacrylate） （PMMA）, and semi-crystalline poly（ethylene oxide） （PEO）. An obvious peak of relaxation type is found in each of the internal friction curves. The peak temperature Tp follows the relation Tp ≈ （1.15- 1.18）Tg for PS and PMMA melts, while it follows Tp ≈ 1.22Tm for PEO melt, with Tg being the glass transition temperature and Tm the melting temperature. Based on the analysis of the features of this peak, it is found that this peak is related to the liquid-liquid transition temperature Tn of polymer melts. Mechanism of the liquid-liquid transition is suggested to be thermally-activated collective relaxation through cooperation. This finding may be helpful to understand the structural changes in polymer melts. In addition, the internal friction technique proves to be effective in studying dynamics in polymer melts.展开更多
文摘采用不同粒径亚微米镍粉与硅橡胶按质量比为2∶1,2.8∶1进行配料,经过特殊的制备方法,制备成镍/硅橡胶高分子复合材料,并主要研究了复合材料的压敏性能和介电性能.通过对材料做性能测试发现当用亚微米镍粉做导电填料时,复合材料具有优异的压敏性能:当仅对材料施加一个200 k Pa压强时,质量比为2.8∶1的镍(400纳米填料)/硅橡胶复合材料的电导率变化了9个数量级.同时,材料的压敏性能会随着导电填料粒径的变化而发生变化.为了充分研究材料的电学性能,实验分别测量出在不同压强下材料的电导率、介电常数随频率的变化数据,研究发现:当频率和压强发生变化时,材料的电导率和介电常数也会发生变化,表现出不同的电荷输运机制.
基金Supported by the National Natural Science Foundation of China under Grant No 10674135, and the Knowledge Innovation Project of Chinese Academy of Sciences （KJCX2-SW-W17）.
文摘With the help of the low-frequency internal friction method, we investigate the structural properties of polymer melts, such as amorphous polystyrene （PS）, poly（methyl methacrylate） （PMMA）, and semi-crystalline poly（ethylene oxide） （PEO）. An obvious peak of relaxation type is found in each of the internal friction curves. The peak temperature Tp follows the relation Tp ≈ （1.15- 1.18）Tg for PS and PMMA melts, while it follows Tp ≈ 1.22Tm for PEO melt, with Tg being the glass transition temperature and Tm the melting temperature. Based on the analysis of the features of this peak, it is found that this peak is related to the liquid-liquid transition temperature Tn of polymer melts. Mechanism of the liquid-liquid transition is suggested to be thermally-activated collective relaxation through cooperation. This finding may be helpful to understand the structural changes in polymer melts. In addition, the internal friction technique proves to be effective in studying dynamics in polymer melts.
