ポリスチレン粉体の成形物の構造に及ぼす成形圧力および温度の影響

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In order to elucidate the hot-pressing process of granular materials, studies were made of the effects of compacting pressure and temperature on the structure of polystyrene powder compact. The kinetic studies showed that within the temperature and pressure range studied, the relation between the percentage of shrinkage S of the powder compact and the compacting time t was expressed by an empirical equation, S=At^k (t>30 sec), in which k was an apparent rate of shrinkage. At a given compacting pressure the temperature dependence of the apparent rate of shrinkage. At a given compacting pressure the temperature dependence of the apparent rate of shrinkage k is characterized by a sharp maximum at a critical temperature T_s. It was found that the critical temperature did not depend on the shape and size of powder particles as was characteristic of polystyrene. This T_s decreased gradually with increasing compacting pressure. The powder compacts had different pore structures depending on the compacting conditions. Thus, for those prepared below T_s pore size and its distribution remained almost unchanged with compacting time, whereas for those above T_s a remarkable change was observed in both of them.As a conclusive summary of these results and discussion, two different mechanisms of hot-pressing of polystyrene powder compacts were suggested, i.e., local deformation of the powder at the contact points below T_s and the overall deformation caused by the softening of polystyrene above T_s. The results of microscopic observation are in favor of the suggested mechanisms.
社団法人日本材料学会の論文
1967-05-15

ポリスチレン粉体の成形物の構造に及ぼす成形圧力および温度の影響

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