聚合MDI中二环化合物含量对发泡性能的影响

A study on the Relationship of Application Performance with 2-Ring MDI Content of Polymeric MDI

制备了不同 2 ,4’ MDI含量、不同二环化合物含量的聚合MDI样品 ,分别与以CFC 11和环戊烷为发泡剂的组合聚醚进行了发泡实验 ,考察了其流动性和脱模性能与组成的关系。实验结果表明 ,当聚合MDI与 2种组合聚醚进行发泡时 ,2 ,4’ MDI含量对聚合MDI的发泡流动性影响较小 ,而对后熟化性能的影响明显 ,随 2 ,4’ MDI含量的增加 ,脱模变形呈直线上升的趋势。与此对应 ,无论是CFC 11型组合聚醚还是环戊烷型组合聚醚 ,二环化合物含量对聚合MDI的发泡流动性能和后熟化性能影响很大 ,是影响聚合MDI应用性能的关键因素。二环化合物含量的增加 ,可以显著地提高泡沫的发泡高度指数、降低密度分布系数 ,改善聚合MDI的发泡流动性能 ,但泡沫的脱模变形量增大 ,后熟化性能明显变差。

A variety of polymeric MDI containing the different MDI isomer content were prepared, and by foaming experiments with CFC-11-type and cyclopentane-type polyols, the relationship of foaming performance with the composition of polymeric MDI were investigated respectively. Experiment results indicated that the foaming flowability of polymeric MDI was almost independent of 2,4'-MDI content in both CFC and cyclopentane foaming systems, but increase in 2,4'-MDI content resulted in linear rise of demoulding deformation. In contrast, the total 2-ring MDI content of polymeric MDI showed marked influence on foaming flowability and curing, and it was a key effect factor to its application performance. With the increase in total 2-ring MDI content, foaming height exponent would rise and foam density distribution coefficient would drop significantly, foaming flowability was bettered. On the contrary, demoulding deformation would grow, curing performance was degraded.