2021-10-04 Pageview:784
This has a very positive effect on painted surfaces where adhesive strength is required. The thinner of high-temperature kitchen coatings is water, and there is a big difference in the construction process between the two compared to solvent-based coatings.
Due to the high surface tension of water, the wettability of water is poor, which leads to high-temperature kitchen coatings to hang and shrink. And the heat of evaporation of water is higher, under the same conditions, the volatilization of water needs more time. Therefore, the construction of high-temperature kitchen coatings is more demanding than solvent-based coatings.
The macroinitiator refers to a polymer compound with a functional group that can be decomposed into free radicals on the molecular chain. The significant advantages of macroinitiators are: ①Almost all monomers can undergo free radical polymerization; ②Very low sensitivity to impurities; ③The molecular weight distribution of block copolymers is usually relatively narrow. The diffusion and reactivity of the macroinitiator are relatively low, which reduces the radical termination reaction and increases the controllability of the reaction. Therefore, it is generally used to synthesize block copolymers.
The preparation method of the macromolecular initiator is: ①Prepare from the reaction of a single-end-capped hydroxyl-terminated polymer or other monofunctional or bifunctional polymer with active small molecule compounds that can generate free radicals; ②Degradation of polymers with high molecular weight (Azo compounds with high molecular weight are partially degraded, and polymers of vinyl monomers are heated and cracked under the action of oxygen or ozone); ③Prepared by bifunctional group condensation polymers. Using macromolecular initiators, atom transfer radical polymerization (AT RP), nitroxide stable radical polymerization and reversible addition fragmentation chain transfer (RAFT) polymerization, etc., block copolymers with controllable structure and narrow molecular weight distribution can be prepared .
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