Peroxide curing process

In spite of the relative weakness of the cross-link bands, the course of the peroxide curing process can be followed to extract kinetic data. Examining Figure 3, where the infrared spectra of (A) natural rubber, (B) dlcumyl peroxide, (C) dlcumyl... 

Diallyl Phthalate Resin Thermoset supplied as diallyl phthalate prepolymer or monomer. Has high chemical, heat and water resistance, dimensional stability, and strength. Shrinks during peroxide curing. Processed by injection, compression, and transfer-molding. Used in glass-reinforced tubing, auto parts, and electrical components. Also called DAP. 

Boron oxide particles were incorporated to silicone rubber-based mixes containing fumed silica (reinforcing filler) and reference mineral fillers - aluminum hydroxide, wollastonite, calcined kaolin, mica (phlogipite) and surface modified montmorillonite with dimethyl-dihydrogenatedtal-low quaternary ammonium salt. Acidic character of boron oxide, which can disturb the peroxide curing process, was compensated by addition of magnesium oxide. The influence of boron oxide particles on properties of composites was determined and mechanism of their ceramization process studied. 

FluorosiHcones (FVMQ) have exceUent low temperature flexibUity properties coupled with good oil, fuel, and solvent resistance and exceUent aging properties. The materials are compounded and reinforced with fine particle fiUers, especiaUy sUica. The materials are mixed and processed on especiaUy clean equipment and are peroxide-cured. 

The early 1980s saw considerable interest in a new form of silicone materials, namely the liquid silicone mbbers. These may be considered as a development from the addition-cured RTV silicone rubbers but with a better pot life and improved physical properties, including heat stability similar to that of conventional peroxide-cured elastomers. The ability to process such liquid raw materials leads to a number of economic benefits such as lower production costs, increased ouput and reduced capital investment compared with more conventional rubbers. Liquid silicone rubbers are low-viscosity materials which range from a flow consistency to a paste consistency. They are usually supplied as a two-pack system which requires simple blending before use. The materials cure rapidly above 110°C and when injection moulded at high temperatures (200-250°C) cure times as low as a few seconds are possible for small parts. Because of the rapid mould filling, scorch is rarely a problem and, furthermore, post-curing is usually unnecessary. 

Crosslinking time is directly dependent on the rate of decomposition of the peroxide. The effectiveness of the overall crosslinking reaction is thus dependent on the type of peroxide and polymer radicals produced during the process. Cure time and temperature can, in a peroxide cure system, be determined solely from knowledge of the rate of peroxide thermal decomposition. 

Peroxide cure systems, in rubber compounding, 22 793-794 Peroxide decomposers, 3 111-114 Peroxide decomposition, 24 279-280 Peroxide formation, by VDC, 25 694. See also Hydrogen peroxide Peroxide initiators, 23 379-380 worldwide producers of, 24 303 Peroxide-ketazine process, 23 582-583 flow sheet for, 23 582 versus Raschig process, 23 583 Peroxide linkages, in VDC polymer degradation, 25 713... 

Cumyl propyl peroxide, determination, 708 Curing processes, 692, 707 Curtin-Hammett principle, electron-poor alkene photooxygenation, 877 Cyanine dye, TBARS assay, 667 Cyanohydrins, bis(trimethylsilyl) peroxide reactions, 797... 

Influences of the different methacrylates and 1,2-polybutadiene as coagents on the mechanical and rheological properties of the peroxide-cured PP/EPDM TPVs were reported by Rishi and Noordermeer [39, 40]. They interpreted the results in terms of solubility parameter and cure kinetics. The effects of coagents on both processing and properties of the compound depend on the nature of the polymer, type of peroxide, and other compounding ingredients. Among the methacrylate... 

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