Polymerization finishing

Modeling and Computer Simulation of a Free-Radical Polymerization Finishing... 

Nearly all polymerization processes and products require a post-reaction process to remove and reduce to an acceptable level residual monomer(s), solvent or diluent. End use properties can be adversely affected by high levels of residuals through toxicity, odor, or poor physical properties. In the cases of residual solvent or diluent, a separation process involving the evaporation of the volatile components (devolatilization) can be used. Devolatilization can be used for residual monomer removal, but completing the polymerization of monomer is an attractive alternative when applicable. Polymerization finishing is usually accomplished with an increase in temperature to kick-off a finishing initiator or the addition of an initiator. (D For the dispersion... 

STONE Free-Radica Polymerization Finishing Process... 

For a polymerization finishing process to be effective and efficient, good or best values of process variables (temperature, choice of initiator, initiator feed rate and amount, and timing) need to be determined. 

Several interesting analogues of structure 11.23 were synthesised recently. These derivatives of 4 methoxynaphthalimide contained a triazine ring with an unsaturated polymerisable substituent capable of addition copolymerisation with other vinyl or acrylic monomers. Such brighteners can be incorporated into the synthesis of polymeric finishes and show exceptional durability to organic solvents and wet treatments [42-44]. 

Reduces or eliminates build up on clips and frames of polymeric finishes... 

TNPP is used as a phospite antioxidant and a stabilizer for elastomers such as SBR, NBR, and SIS. Used as a stabilizer and a chelator/complexing agent in PC, PE, PP, PVC, copolymers such as ABS (Acrylonitrile-Styrenic based), SBR, and EVA (Ethylene-vinyl acetate) and in polymer latex and other aqueous systems. TNPP also prevents gel formation during polymerization finishing, storage, and factory processing. 

From the viewpoint of prediction of service lives, the photochemical deterioration processes of polymers used as paints and finishes are theoretically analyzed based upon unsteady state dynamics. Theoretical results are compared with experimental data under natural and accelerated exposure. Infrared spectra and scanning micrographs show that the deterioration proceeds continuously inwards from the surface, but differently with the exposure conditions. Parabolic (/t ) law was derived approximately for the increase in the depth of the deteriorated layer of polymers with time. Paying attention to the influence of the deterioration of polymeric finishes, the parabolic law involving a constant term was also derived for the progress of carbonation of concrete. These parabolic laws well predict the progress of deterioration and explain the protective function of finishes on reinforced concrete. 

Retardation Effects of Polymeric Finishes on Carbonation. The retardation effects of polymeric finishes can be well explained, using equations 9. and 12., where I is the constant term which includes total surface mass transfer constant, and describes the retardation of carbonation or induction period before the carbonation begins to proceed. From equation 9. it can be seen that the effects depend on the thickness and diffusion coefficients of finishes (Figure 13). 

Paying attention to the influence of the deterioration of polymeric finishes, the parabolic law involving a constant term was also derived for the progress of carbonation of concrete. These parabolic laws combined predict the progress of the deterioration under natural weathering and explain well the protective performance of finishing materials on reinforced concrete. 

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