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Selection Of Initiator

Jul 14, 2020

Initiators and polymerization inhibitors are a pair of opposite additives in the curing reaction of unsaturated polyester and crosslinking monomers. The initiator decomposes to produce highly active free radicals, which attack crosslinking monomers (such as styrene) and The unsaturated double bond in the polyester molecular chain activates it to cause a cross-linking reaction. On the contrary, the polymerization inhibitor can absorb or "neutralize" the free radicals generated by the decomposition of the initiator and prevent the cross-linking and curing of the resin. .

The initiator must be decomposed and activated under external conditions, otherwise it will decompose slowly at room temperature and cannot meet the process requirements. This external condition is one of heating; the other is a chemical reaction. The former causes the initiator to thermally decompose, the latter Through redox reaction, the initiator is decomposed. This kind of reducing agent that can activate the initiator is called "accelerator".

The application of unsaturated polyesters is becoming more and more extensive, the variety is increasing, the molding methods are gradually diversified, and various initiators, accelerators and polymerization inhibitors with different characteristics are required, and the cost is low and the use is safe. Therefore, for various additives The research has been paid attention to. These additives have their different performance and use requirements. At the same time, the combination of two or more initiators, accelerators, accelerators, polymerization inhibitors, stabilizers and other methods have become popular In order to balance the promotion and stabilization, the resin's gel, curing and exothermic parameters are effectively adjusted and controlled, which meets the requirements of the use process.