An experimental study on the effect of polymer viscoelasticity on layer rearrangement in coextruded structures.: An article from: Polymer Engineering and Science
Book Details
PublisherSociety of Plastics Engineers, Inc.
ISBN / ASINB00098A7DS
ISBN-13978B00098A7D0
AvailabilityAvailable for download now
Sales Rank99,999,999
MarketplaceUnited States 🇺🇸
Description
This digital document is an article from Polymer Engineering and Science, published by Society of Plastics Engineers, Inc. on July 1, 1998. The length of the article is 3847 words. The page length shown above is based on a typical 300-word page. The article is delivered in HTML format and is available in your Amazon.com Digital Locker immediately after purchase. You can view it with any web browser.
From the author: Previous work on the layer thickness uniformity of coextruded structures has centered primarily on the effects of differing polymer viscosities in the individual layers. These differences in viscosities result in a phenomenon known as "viscous encapsulation" in which the less viscous layer tends to encapsulate the more viscous layer producing nonuniform layer thicknesses. In this study, the effect of polymer viscoelasticity on the layer thickness uniformity of multilayer coextruded structures was investigated by coextruding multilayer structures through die channels of different cross-sectional shapes and observing the location of the interface. In order to minimize the viscosity effects, the coextrusion experiments were conducted with identical materials in each layer that were pigmented to allow observation of the layer interface. It was shown experimentally that coextruding identical polymers through channels of various geometries can cause the layers to rearrange. This layer rearrangement appears to be caused by secondary flows that occur in different channel geometries due to the viscoelastic characteristics of the polymer. Layer rearrangement of identical polymers implies that even resins with viscosities well matched for coextrusion may experience nonuniform layer thicknesses when coextruded through large dies.
Citation Details
Title: An experimental study on the effect of polymer viscoelasticity on layer rearrangement in coextruded structures.
Author: Joseph Dooley
Publication:Polymer Engineering and Science (Refereed)
Date: July 1, 1998
Publisher: Society of Plastics Engineers, Inc.
Volume: v38 Issue: n7 Page: p1060(12)
Distributed by Thomson Gale
From the author: Previous work on the layer thickness uniformity of coextruded structures has centered primarily on the effects of differing polymer viscosities in the individual layers. These differences in viscosities result in a phenomenon known as "viscous encapsulation" in which the less viscous layer tends to encapsulate the more viscous layer producing nonuniform layer thicknesses. In this study, the effect of polymer viscoelasticity on the layer thickness uniformity of multilayer coextruded structures was investigated by coextruding multilayer structures through die channels of different cross-sectional shapes and observing the location of the interface. In order to minimize the viscosity effects, the coextrusion experiments were conducted with identical materials in each layer that were pigmented to allow observation of the layer interface. It was shown experimentally that coextruding identical polymers through channels of various geometries can cause the layers to rearrange. This layer rearrangement appears to be caused by secondary flows that occur in different channel geometries due to the viscoelastic characteristics of the polymer. Layer rearrangement of identical polymers implies that even resins with viscosities well matched for coextrusion may experience nonuniform layer thicknesses when coextruded through large dies.
Citation Details
Title: An experimental study on the effect of polymer viscoelasticity on layer rearrangement in coextruded structures.
Author: Joseph Dooley
Publication:Polymer Engineering and Science (Refereed)
Date: July 1, 1998
Publisher: Society of Plastics Engineers, Inc.
Volume: v38 Issue: n7 Page: p1060(12)
Distributed by Thomson Gale
