Thermally expandable microcapsules for polymer foaming-Relationship between expandability and viscoelasticity
A new thermally expandable microcapsule was developed for use with foaming polypropylene (PP) by injection molding and extrusion processes at operating temperatures above 200°C. The microcapsule consists of a blowing agent as the core and a shell polymer. The rheological properties of the shell poly...
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Published in | Polymer engineering and science Vol. 50; no. 4; pp. 835 - 842 |
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Main Authors | , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Hoboken
Wiley Subscription Services, Inc., A Wiley Company
01.04.2010
Wiley Society of Plastics Engineers, Inc Blackwell Publishing Ltd |
Subjects | |
Online Access | Get full text |
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Summary: | A new thermally expandable microcapsule was developed for use with foaming polypropylene (PP) by injection molding and extrusion processes at operating temperatures above 200°C. The microcapsule consists of a blowing agent as the core and a shell polymer. The rheological properties of the shell polymer were controlled by a crosslinking agent to design the expandability and shrinkage. The effects of rheological properties on the expandability and the surface appearance of foam products were thoroughly investigated. It was found that storage modulus G′ and tan δ significantly affected the expandability and shrinkage and were controllable through crosslinking polymerization. Visual observation of batch foaming, rheological measurement, and experiments of foam injection molding and extrusion elucidated the existence of the optimal degree of crosslinking that could realize more than 30% density reduction while maintaining a smoothsurface at PP foam injection molding and extrusion. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers |
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Bibliography: | istex:0D24A2C835D0AF19461EEF47403EF5ECED082CBC ArticleID:PEN21595 Part of the paper was presented at the ANTEC meeting (Chicago), 2009. ark:/67375/WNG-46XB8H7Z-F ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 |
ISSN: | 0032-3888 1548-2634 |
DOI: | 10.1002/pen.21595 |