Nanoporous Membranes by Solventless Melt Processing and Post-Treatments

纳米多孔聚合物过滤膜的常规制造方法采用有机溶剂，导致膜具有宽的孔径分布和有限的耐有机溶剂性。 产生了大量被溶剂污染的含水废物。 初步研究已经描述了一种新颖的和普遍适用的无溶剂技术，用于从多组分聚合物体系制备纳米多孔膜，该多组分聚合物体系含有基质相和不混溶的次要相，具有/不具有相容性嵌段共聚物。 该方法包括将多组分聚合物体系熔融挤出成膜并对其进行挤出后处理，该挤出后处理包括拉伸步骤，导致基质中的连续微裂纹和通过脱粘在相界面处的孔。 提出了这样一种技术的一般调查，用于制作平面纳米多孔膜。 具体的研究目标和方法如下：（1）将不相容聚合物共混物的范围从两大类聚合物组合：半晶/无定形和具有不同熔融温度的半晶/半晶，扩展到各种体系。 系统选择将考虑它们的极性、亲水性、结晶度、熔融温度、熔体粘度和弹性以及分子量和分布。 (2)建立了薄膜挤出和后处理条件之间的详细加工/结构/性能相关性，开发了前体固体膜形态和纳米多孔膜结构。 (3)研究这种膜在超滤、纳滤、微滤、支撑液膜渗透作为皮肤屏障模拟物和电池隔膜应用中的分离特性。 (4)分析所提出的无溶剂膜制造方法相对维斯现有的溶剂型膜制造过程的显著降低的总体环境影响。这些研究目标的成功实现将建立一种环境友好的通用无溶剂技术，该技术制造具有多种商业上有用的分子/蛋白质/纳米颗粒混合物的分离和传输能力的平坦纳米多孔聚合物膜。 该制造方法将具有立即扩展到中空纤维膜的潜力。 了解这种制膜技术的科学及其潜力将有助于开发新型纳米多孔膜。 一名研究生和一名博士后将接受膜制造、膜表征和膜工艺方面的教育。 聚合物加工研究所和NJIT膜技术中心之间的合作将把现有的合作推向更高的水平。

Conventional fabrication methods for nanoporous polymeric filtration membranes employ organic solvents resulting in membranes having a wide pore size distribution and limited organic solvent resistance. Large volumes of solvent-contaminated aqueous wastes are produced. Preliminary studies have described a novel and generally applicable solventless technique for making nanoporous membranes from a multicomponent polymer system containing a matrix phase and an immiscible minor phase with/without a compatibilizing block copolymer. The method involves melt extrusion of the multicomponent polymer system into a film and subjecting it to post-extrusion treatments involving stretching steps leading to continuous microcracks in the matrix and pores at the phase interface via debonding. A general investigation of such a technique for making flat nanoporous membranes is proposed. The specific research objectives and the corresponding methods are as follows: (1) Broaden the range of immiscible polymer blends to a variety of systems from two broad classes of polymer combinations: semicrystalline/amorphous, and semicrystalline/semicrystalline with different melting temperatures. System selection will consider their polarity, hydrophilicity, degree of crystallinity, melting temperature, melt viscosity and elasticity and molecular weight and distribution. (2) Established the detailed processing/structure/property correlations between film extrusion and post-treatment conditions, the precursor solid film morphology and the nanoporous membrane structure developed. (3) Investigate the separation characteristics of such membranes in ultrafiltration, nanofiltration, microfiltration, supported liquid membrane permeation as a skin-barrier analog and battery separator applications. (4) Analyze the drastically reduced overall environmental impact of the proposed solventless membrane manufacturing method vis-a-vis existing solvent-based membrane making process.Successful achievement of these research objectives will establish an environmentally friendly general solventless technique of making flat nanoporous polymeric membranes having a variety of commercially-useful separation and transport capabilities for mixtures of molecules/proteins/nanoparticles. The manufacturing methodology will have immediate potential for extension to hollow fiber membranes. Understanding the science of this membrane-making technology and its potential will facilitate development of novel nanoporous membranes. A graduate student and a post-doctoral fellow will be educated in membrane fabrication, membrane characterization and membrane processes. Collaboration between Polymer Processing Institute and the Center for Membrane Technologies at NJIT will advance existing cooperation to a higher level.