Partial Compatibility and the Formation of Thickened, Shrink-Resistant Thermoset Moulding Compounds

This paper describes a new class of thermosetting polymer blends. The blends are now used commercially in the manufacture of sheet moulding compounds (SMC) where they exhibit important advantages compared with conventional systems. The new compositions comprise a cross-linkable base resin and unsatu...

Full description

Saved in:
Bibliographic Details
Published in:High performance polymers 1996-03, Vol.8 (1), p.67-82
Main Authors: Bush, S F, Methven, J M, Blackburn, D R
Format: Article
Language:English
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:This paper describes a new class of thermosetting polymer blends. The blends are now used commercially in the manufacture of sheet moulding compounds (SMC) where they exhibit important advantages compared with conventional systems. The new compositions comprise a cross-linkable base resin and unsaturated monomer in which the base resin is dissolved and a saturated additive resin which has a crystalline melting temperature Tm below the temperature Tr at which cross-linking occurs. Between Tr and Tm the additive and base resin form a single liquid phase, which on cooling thickens reversibly to a leathery sheet with no bulk phase separation. The paper describes the mechanisms underlying this viscosity switch phenomenon and the partial compatibility criterion used to select the resin-additive combinations which exhibit this behaviour.
ISSN:0954-0083
DOI:10.1177/095400839600800105