Polypropylene blends with potential as materials for microporous membranes formed by melt processing
Polypropylene blends with potential as materials for microporous membranes formed by melt processing
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DOI：
10.1016/s0032-3861(01)00654-1
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发表时间：
2002-02-01
期刊：
影响因子：
4.6
通讯作者：
Gogos, CG
中科院分区：
文献类型：
--
作者：
Chandavasu, C;Xanthos, M;Gogos, CG
以不相容的聚丙烯共混物为原料，通过熔融加工和挤出后处理制备了孔径为2 ~ 25 nm的新型微孔膜。使用含有聚苯乙烯和聚对苯二甲酸乙二醇酯作为次要相组分的体系作为起始膜材料，浓度不超过15重量%。共混物首先在同向旋转双螺杆挤出机中混配，随后通过片材模头挤出以获得无孔前体膜。这些在低于次要相的玻璃化转变温度的温度下相对于原始尺寸进行单轴拉伸（100-500%）以诱导微孔结构，然后在升高的温度下进行后处理以稳定多孔结构，该多孔结构由宽度为几纳米量级的均匀微裂纹组成。分散相浓度和组分熔体流变性对固体和微孔共混物形态的影响。在固态的拉伸操作的有限元建模产生了一个成功的解释的共混物响应单轴拉伸，导致微裂纹的形成。在这项工作中开发的过程可以被认为是无溶剂的替代品相转化生产实践的膜含有中孔。(C)2001爱思唯尔科技有限公司版权所有。
Novel microporous membranes with pore size ranging from 2 to 25 nm were produced from immiscible polypropylene blends via melt processing and post-extrusion treatments. Systems containing polystyrene and polyethylene terephthalate as the minor phase components were employed as starting membrane materials at concentrations not exceeding 15 wt%. The blends were first compounded in a co-rotating twin-screw extruder and subsequently extruded through a sheet die to obtain the non-porous precursor films. These were uniaxially drawn (100-500%) with respect to the original dimensions at a temperature below the glass transition temperature of the minor phase to induce a microporous structure and then post-treated at elevated temperatures to stabilize the porous structure, which consisted of uniform microcracks in the order of a few nanometers in width. The effects of dispersed phase concentration and component melt rheology on the solid and microporous blend morphologies are presented. Finite element modeling of the stretching operation in the solid state yielded a successful interpretation of the blend response to uniaxial tension that resulted in microcrack formation. The processes developed in this work may be considered as solventless alternatives to phase inversion manufacturing practices for membranes containing mesopores. (C) 2001 Elsevier Science Ltd. All rights reserved.