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Article: The application of stress relaxation to quality control of polyisobutylene.
- Article from:
- Rubber World
- Article date:
- October 1, 1996
- Author:
CopyrightCOPYRIGHT 1996 Lippincott & Peto, Inc. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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Polyisobutylene rubber (IM) is produced at molecular weights ranging into several millions resulting in extremely high polymer viscosities. These high viscosities make it impossible to apply simple rheological tests for measuring common MW parameters, such as Mooney viscosity or melt flow rate. An additional concern with high MW polymers is shear degradation. Dynamic tests at low strains can yield MW information, but for high MW very low test frequencies are required which imply impractical slow tests and require highly sensitive instruments. MW of IM is therefore commonly determined by dilute polymer solutions methods such as GPC and intrinsic viscosity. The later test is ...