Kinetics polymerization, poly

Keywords graft polymerization kinetics poly(methyl acrylate) RAFT polymerization siiica... 

An alternating copolymer of a-methyl styrene and oxygen as an active polymer was recently reported [20]. When a-methyl styrene and AIBN are pressurized with O2, poly-a-methylstyreneperoxide is obtained. Polymerization kinetic studies have shown that the oligoperoxides mentioned above were as reactive as benzoyl peroxide, which is a commercial peroxidic initiator. Table 1 compares the overall rate constants of some oligoperoxides with that of benzoyl peroxide. 

Swarc,M. The Kinetics and Mechanism of N-carboxy-a-amino-acid Anhydride (NCA) Polymerization to Poly-amino Acids. Vol. 4, pp. 1—65. 

The polymerization kinetics have been intensively discussed for the living radical polymerization of St with the nitroxides,but some confusion on the interpretation and understanding of the reaction mechanism and the rate analysis were present [223,225-229]. Recently, Fukuda et al. [230-232] provided a clear answer to the questions of kinetic analysis during the polymerization of St with the poly(St)-TEMPO adduct (Mn=2.5X 103,MW/Mn=1.13) at 125 °C. They determined the TEMPO concentration during the polymerization and estimated the equilibrium constant of the dissociation of the dormant chain end to the radicals. The adduct P-N is in equilibrium to the propagating radical P and the nitroxyl radical N (Eqs. 60 and 61), and their concentrations are represented by Eqs. (62) and (63) in the derivative form. With the steady-state equations with regard to P and N , Eqs. (64) and (65) are introduced, respectively ... 

Jabarin, S. A. and Lofgren, E. A., Solid state polymerization of poly (ethylene terephthalate) kinetic and property parameters, J. Appl. Polym. Sci., 5315-5335 (1986). 

Chen, S. and Chen, F Kinetics of polyesterification III Solid-state polymerization of poly(ethylene terephthalate),. /. Polym. Sci., Polym. Chem. Ed., 25, 533-549 (1987). 

With over 200 million dental restorations performed each year, the importance of developing a restorative material with tooth-like appearance and properties cannot be underestimated. In this article, the use of poly (multimethacrylates) as dental composites is summarized from both fundamental and practical sides. Detail is provided regarding the utilization, procedures, and problems with polymeric composite restoratives, and a complete discussion of the polymerization kinetics and the polymer structural evolution is presented, fn the final sections, properties of current composite materials and suggestions for what areas of research would prove most promising are presented. 

Poly(vinyl pyrrotidone). Another commercial polymer with significant usage is PVP. It was developed in World War II as a plasma substitute lor blood. This monomer polymerizes faster in 50 water than it does in bulk, an abnormality inconsistent with general polymerization kinetics. This may be due to a complex with water that activates the monomer it may also be related to the impurities in the monomer that are difficult to remove. See also Vinyl Acetal Polymers. 

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