Novel polypropylene-based microporous membranes via spherulitic deformation

Document Type

Article

Publication Date

3-2-2009

Abstract

A novel method for creating a microporous membrane via spherulitic deformation is illustrated. The microporous structure was generated by the combination of intra-spherulitic and inter-spherulitic deformations. Polypropylene was selected due to its unique cross-hatched lamellar morphology facilitating inter-spherulitic deformation. A precursor film with a spherulitic structure was made under low-stress melt processing condition. A tangential lamellae-rich spherulite was created and identified with a positive birefringence sign. A sequential annealing process improved the crystalline structure, and in particular the thickness of the tangential lamellae. The annealing process proved to be critical for initiating the inter-spherulitic deformation. A WAXS examination provides a quick characterization method for the inter-spherulitic deformation. A highly interconnected solvent-resistant porous polypropylene membrane having a pore size in the range of 50-100 nm and a porosity of about 0.18 was thereby developed in this study. This concept can be further expanded by using an α-nucleating agent to reduce spherulite sizes. A highly methanol permeable membrane with an estimated porosity of 0.29 was produced with the nucleated polypropylene samples. © 2009 Elsevier B.V.

Identifier

60549092239 (Scopus)

Publication Title

Journal of Membrane Science

External Full Text Location

https://doi.org/10.1016/j.memsci.2008.12.060

ISSN

03767388

First Page

267

Last Page

278

Issue

1-2

Volume

330

Grant

DMI-0327968

Fund Ref

National Science Foundation

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