The wetting/leveling agent can effectively reduce the surface tension of the system and significantly improve the construction effect of water-based paint. The addition of wetting and leveling agents increases the wetting and penetration of the paint to the substrate, improves the leveling of the paint, and sometimes overcomes the problem of shrinkage.
Leveling agents can solve common shrinkage problems, especially those caused by excessive use of defoamers. Excessive leveling agent will offset the defoaming effect of defoamer, making the paint bubble during construction, should try to use low foaming, good leveling and small stabilizing foam wetting leveling agent. Leveling agent and defoamer cooperation, including the selection of species and dosage control, is the focus of water-based paint formulation research.
Atom transfer radical polymerization (AT RP polymerization for short) refers to the reversible transfer in the polymerization reaction, that is, the reversible transfer of halogen atoms, oxidized polyethylene wax msds including the transfer of halogen atoms from organic halides to metal halides, and then from metal halides to free radicals. The cyclic atom transfer process is accompanied by the reversible conversion equilibrium reaction between the active species of free radicals (proliferating chain free radicals) and the dormant species of macromolecular organic halides to inhibit the active species of free radicals and keep them at a lower concentration , To reduce the irreversible bimolecular termination side reaction between the growing chain free radicals, so that the polymerization reaction can be effectively controlled. The polymerization mechanism of AT RP is shown in formula (4-38).
R—X+2bipy/CuX-R.+2bipy/CuX: -nMP: +2bipy/CuX,
bip y is irreversible\termination of bipyridine
A “dead” polymer
The research of AT RP mainly includes three aspects: new initiation and polymerization system, polymer structure and material properties, polymerization reaction process and industrial product development, among which the research of new initiation system attracts the most attention. The initiation system of AT RP polymerization is mainly composed of initiator, catalyst and complexing agent.
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