A study of dynamic vulcanization for polyamide‐12 and chlorobutyl rubber

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, structure 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.

Effect of butyl rubber type on properties of polyamide and butyl rubber blends

“…In previous studies undertaken on polyamide/butyl rubber blends in our laboratories 16,17 it was shown that these two normally incompatible systems can be mixed in a high shear environment with and without the presence of curing agents added. The high shear environment seems responsible for producing an interaction between the polyamide and rubber components during processing.…”

“…Hexane extraction of the mixtures and measurement of percentage insolubles along with swelling index of the rubber phase confirm that a high level of cure is likely achieved using low levels of curing agents. 17 The objective of the present study was to examine a variety of PA/butyl rubber blends prepared with and without dynamic vulcanization. To observe the effect of the rubber properties on the blend, the butyl rubbers were varied in halogen content, halogen type, percentage unsaturation, and Mooney viscosity.…”

Activation of bifunctional coupling agents in fiberglass/polyethylene composites by electron beam

“…In 10 min of heating at 150°C the decomposition reaction of the diazoketone group, and the subsequent reaction with the glass surface, is virtually complete. 5 Thus, heat is the preferred treatment to bind these coupling agents to a glass surface.…”

“…Creep behavior drops dramatically when a silane coupling agent is present. 4 In the first study of this series, 5 the decomposition of two compounds, 12-azido-1-diazo-2-dodecanone (compound A) and 1-diazo-17-octadecene-2-one (compound B), under heat and UV light was studied. The effectiveness with which heat and UV light were able to bind these compounds to the surface of glass fibers was also investigated.…”

Morphology and mechanical properties of ethylene‐vinyl acetate rubber/polyamide thermoplastic elastomers

“…Thermoplastic polyamide (PA)-based TPEs with nonpolar or polar rubbers as the second components, such as ethylene-propylene diene terpolymer, [1][2][3][4][5][6][7][8] ethylene-propylene rubber, 9 natural rubber, 10 butadiene-acrylonitrile copolymer, [11][12][13][14][15][16][17] hydrogenated butadiene-acrylonitrile copolymer, 18-21 acrylate rubber, [22][23][24] and halogenated butyl rubber 17,[25][26][27][28] have been investigated intensively by applying dynamic vulcanization technique, and the resultant PA-based TPEs have found wide applications in sports, transport, and construction areas.…”