Peroxide curing agents

The polyester alkyd moulding compositions are also based on a resin similar to those used for laminating. They are prepared by blending the resin with cellulose pulp, mineral filler, lubricants, pigments and peroxide curing agents on... 

After formulation with a flame retardant filler such as alumina trihydrate Al203 3H20, hydrated silica or calcium carbonate, a peroxide curing agent and... 

Aliphatic or aromatic peroxide curing agents can also be used, by reactions with vinyl side chains or even saturated alkyl groups. Specihc peroxides are chosen on the basis of their decomposition temperatures, and the reaction products they leave behind after the curing process is complete. Some peroxides used are Mv(2,4-dichloroben-zoybperoxide, benzoyl peroxide, dicumyl peroxide, and di-t-butyl peroxide.83-86... 

Figure 1.8 EPDM rubber with peroxide curing agent, detection of cumyloxy fragments...

Experiments were performed on DC745U and M97 silica-filled silicone polymers as described elsewhere [1-5]. The gum stocks for all formulations were co-block polymers of dimethylsiloxane, diphenylsiloxane, methylphenylsiloxane, and/or methylvinyl siloxane. The gum stock was reinforced with high surface area silica filler and crosslinked with peroxide curing agents. These materials were tested in both new as well as service return conditions. 

Ac yiacetone peroxide curing agent, thermosets Isopropyl tridodecylhenzenesuUonyl titanate Ken-React KR 7 Ken-React KR 9S Ken-React KR 12 Ken-Read KR 26S Ken-React KR 33DS Ken-Read KR 38S Ken-React KR 41B Ken-Read KR 44 Ken-Read KR 46B Ken-React KR 55 Ken-React ... 

FKMs are compounded in either water-cooled internal mixers or two-roll mills. A two-pass mixing is recommended for internally mixed com-poimds with the peroxide curing agent added in the second pass. Compoimds press-cured 10 min 350°F (177°C) can be formulated to possess more than 2100-lb/in (14.4-MPa) tensile strength, 380% elongation, 525% 100% modulus, and higher values when postcured 16 h 392°F (200°C).ii Processing temperatures are >392°F (200°C). ... 

Peroxide-curing agents are effective at crosslinking most rubbers. Exceptions to this are butyl and chlorobutyl rubber, some polyacrylates and some fluoropolymers (these being grade dependent). Peroxides form direct carbon-carbon crosslinks, which are... 

The first peroxide cure agents were used in 1929. But the vulcanizates obtained had poor physical properties, and poor resistance to heat ageing when compared to sulfur-cured vulcanizates. 

Fiberglass panels can be made from glass fibers, a liquid polyester syrup, and styrene plus a peroxide curing agent. Polymerization of the styrene and the resin occurs but secondary reactions can be carried out on the unreacted hydroxyl ends of the polymer. The extent of these reactions depends upon the number of unreacted ends remaining. How much hydroxyl is there in the resin We need it in a hurry,... 

One problem associated with this task is that a number of peroxide curing agents breakdown to give more that one product and a number of these are common to more than one peroxide species. This is demonstrated in Table 7. 

Vinyl groups are usually introduced at very low levels and substitute for a methyl group in the structure shown. This allows a greater variety of peroxide curing agents to be used to crosslink the rubber as well as obtaining better compression set properties as in the case of dimethyl rubber. 

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