Morphology of fibers formed via thermally induced phase separation of polypropylene / liquid paraffin blend in stress-field and the properties of membrane obtained

摘要

The thermally induced phase separation (TIPS) process has been utilized for making microporous materials, such as membranes and foams, from semicrystalline polymers. TIPS of polypropylene with various diluents have been investigated. On other hand it is well known that semicrystalline polymers melted spun under high take-up ratio have a row nucleated structure of stacked lamellae normal to the fiber direction, and such polymers are named as springy, or 'hard-elastic' polymers . The mechanism of the formation of such structure has been investigated by J.E.Spruiell et.al.[3]. By extension of hard-elastic polymers micropous membranes were obtained. It was found that the hard elastic fibers also could be prepared from the blend of polypropylene and the blend of isotactic polypropylene with atactic polypropylene. Up to now, however, there has been no report of the morphology of the thermally induced phase separation of polymer-diluent system in a stress field. In this work morphology of polypropylene/liquid paraffin blend crystallized in the stress field was studied. Elastic fiber was obtained from the blend melt spun with high take-up draw ratio. The feasibility of membrane preparation from such fibers was proposed.