A Study of Dynamic Vulcanization for Polyamide-12 and Chlorobutyl Rubber

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Authors
  1. Van Dyke, J.D.
  2. Gnatowski, M.
  3. Koutsandreas, A.
  4. Burczyk, A.F.
Corporate Authors
Defence R&D Canada - Suffield, Ralston ALTA (CAN)
Abstract
Polyamide-12 and chlorobutyl rubber were blended by dynamic vulcanization in a high shear environment using curing systems based on sulfur, dithiocarbamate/ZnO, and 4,4-methylenebiscyclohexylamine/MgO. As expected, all blends with curing agents show increased tensile strength and elongation at break in comparison to blends without curing agents. Maximum mechanical properties are obtained at relatively low levels of curing agent in all systems. Hexane extraction of the mixtures and measurement of percentage of insolubles along with the swelling index of the rubber phase confirm that a high level of cure is achieved at low levels of curing agent. Although the curatives are designed for the rubber phase, differential scanning calorimetry results indicate that both phases are affected during the dynamic vulcanization process, with polyamide-12 showing a reduced melting temperature that is indicative of molecular weight reduction, structures changes, or reaction with the rubber phase. Scanning electron microscopy results indicate that phase size is reduced with increased blending time and level of curing agent. Rheological studies indicate that blends containing curing agents exhibit non-Newtonian behavior to a greater extent than polyamide or nonvulcanized polyamide/chlorobutyl rubber blends.
Keywords
Dynamic vulcanization
Report Number
DRDC-SUFFIELD-SL-2002-051 — Scientific Literature
Date of publication
20 May 2002
Number of Pages
10
DSTKIM No
CA024167
CANDIS No
521678
Format(s):
Hardcopy;Document Image stored on Optical Disk

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