Microlayer polymer structures via melt processing

Leon Levitt, Takushi Saito, Chris Macosko

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Layered polymer microstructures have useful properties. Very regular, thin (<1 μm) microlayer structures are iridescent or mirror-like and can function as optical filters. Microlayer structures can also show enhanced mechanical properties. Even less regular and thicker layers can dramatically alter the permeability of the matrix polymer. We demonstrate that such layered structures arise naturally when 10-100 μm diameter drops of one polymer melt are sheared within another. This is due to the weak influence of interfacial tension compared to shear stress. A high second normal stress difference in the matrix can actually cause the drops to widen. Adding a block copolymer to the drops or grafting reactions across the interface greatly enhances area generation. Stretching microlayer structures in an extensional rheometer generates new interfacial area exponentially. Samples can be prepared by stacking alternating layers followed by compression in a heated press and also by multilayer coextrusion. Using 50 or more layers enhances interfacial effects permitting direct measurement of interfacial tension and grafting reactions. Interfacial tension is found to increase strongly with rate of area generation. Grafting reactions also increase interfacial effects rather than decrease as had been expected from some studies.

Original languageEnglish (US)
Title of host publicationTechnical Papers, Regional Technical Conference - Society of Plastics Engineers
Editors Anon
PublisherSoc Plast Eng
Number of pages1
StatePublished - Dec 1 1997
EventProceedings of the 1997 International Symposium on Polymer Blends, Alloys and Filled Systems, POLYBLENDS - Boucherville, Can
Duration: Oct 9 1997Oct 10 1997

Other

OtherProceedings of the 1997 International Symposium on Polymer Blends, Alloys and Filled Systems, POLYBLENDS
CityBoucherville, Can
Period10/9/9710/10/97

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