【摘要】 将环烯烃共聚物样品在超临界CO2 条件下饱和后 ,先将体系降至一中间压力 ,而后采用 4种不同的方法分次降压和快速冷却 .通过 4种降压和冷却模式的比较 ,初步研究了快速降压法微孔发泡的成核及增长过程 .并得到了几种新颖结构的微孔 ,如具有过渡层结构以及直径呈双峰分布的微孔等 .研究表明 ,泡孔充分增长过程中绝大部分气核消失或合并 ,只有很少一部分最终生长为稳定的泡孔结构 ,而不同的泡孔增长过程对最终的泡孔结构有很大影响 .二次成核只有在一定的压降范围内才能发生 .两次降压得到的泡孔结构与该降压幅度下气体溶解度的变化密切相关更多还原

【Abstract】 The cell nucleation and cell growth of microcellular foaming in supercr itical CO 2 pressure quench process was investigated by means of dual depressur iz ation and cooling.Cyclic Olefin Copolymer (COC) was saturated under supercritic al CO 2 circumstance,and then the system was depressurized to an intermediate pr essure.After that,four methods of re depressurization and cooling were adopte d .Several novel cell structures were prepared in this way,such as cells with tr ansitional layers and bimodal size distribution cells.It was found that most of the nuclei disappear or coalesce during cell growth process with only a small f raction growing to stable cells,and the final cell structure strongly depends o n the cell growth process.Dual nucleation occurs only in a certain depressurizat io n range.Final cell structures obtained in dual depressurization are closely corr elative to the solubility variation of CO 2 under corresponding pressures.更多还原