预成型形状对发泡乙丙橡胶泡孔形态和动态力学性能的影响

Effect of Preform Shape on Cell structure and Dynamic Mechanical Properties of Foaming EPDM

考察了混炼胶预成型形状对发泡乙丙橡胶硫化/发泡过程、泡孔形态及其动态力学性能的影响。结果表明,预成型形状和填充量,不仅影响硫化时间、发泡压力等工艺性能,对发泡橡胶的泡孔尺寸、动态力学性能也具有显著的影响。随预成型样品的厚度增加,硫化转矩和发泡压力增加,焦烧时间t10和正硫化时间t90变化不大;三角型样品和碎胶样品的t90延长,而超量填充胶料时t10和t90较短。随预成型厚度减小,泡孔尺寸逐渐增加,动态模量减小,损耗因子增加;三角型样品的泡孔较大,但动态模量高于8mm样品,表明发泡橡胶的动态模量与受力测试方向上的取向有关,而与其垂直方向上的取向无关。填充橡胶量较大时,泡孔最小,而且损耗模量G″-应变曲线出现第二个峰,表明较小的泡孔容易在较低形变下发生破坏。

Different compounds with preform shape were designed and cured in the foam-curemeter and rubber processor analyzer.The shape had apparent influence on cell structure and dynamic mechanical properties of foaming rubber.The foaming pressure and curing torque were increased as increaseing of the thickness while the scorch time（t10） and optimum time（t90） had little change.The triangle specimen and particle-type specimen had longer t90,and the excessive（mass of rubber for cure） filled one had shorter t10 and t90.The cell area was increased and dynamic moduli was decreasd as decreasing of preform thickness.However,the triangle specimen with bigger cell had higher moduli,which indicated the moduli of foaming rubber had relationship with the orientation along the measuring force but the vertical.The excessive filled specimen had minimal cell and showed another peak in loss modulus G″-strain curve.It was proved that the smaller cell was easy to be destroied at lower deformation.