Polymerization copolymerizations

Despite numerous efforts, there is no generally accepted theory explaining the causes of stereoregulation in acryflc and methacryflc anionic polymerizations. Complex formation with the cation of the initiator (146) and enoflzation of the active chain end are among the more popular hypotheses (147). Unlike free-radical polymerizations, copolymerizations between acrylates and methacrylates are not observed in anionic polymerizations however, good copolymerizations within each class are reported (148). 

Unlike ftee-tadical polymerizations, copolymerizations between acrylates and methacrylates ate not observed in anionic polymerizations however, good copolymerizations within each class ate reported (99). 

Allcock, H. R., Schmutz, J. L., and Kosydar, K. M., A new route for poly(organophosphazene) synthesis. Polymerization, copolymerization, and ring-ring equiUbration of trifluoroethoxy-and chloro-substituted cyclotriphosphazenes, Macromolecules. 

Homopolymerization of ethyl 4-vinyl-a-cyano-p-phenylcinnamate with AIBN in benzene gave a soluble polymer of inherent viscosity 0.2 djf,/g. There was no evidence for involvement of the tetra-substituted double bond in the polymerization. Copolymerizations with styrene and methyl methacrylate were also successful. 

His plan to concentrate research in the area of polymerization mechanisms was in the beginning more requirement than choice. On arriving in Vienna, Mark quickly realized that less experienced hands could not prepare monomers and polymers at the speed and purity necessary to compete with the Ludwigschafen and Freiburg laboratories. Thus early on, research was directed toward observing polymerization, copolymerization, and reaction... 

Ziegler-Natta (or Natta-Ziegler) catalyst (ZNC) Able to produce stereoregular pol5uners. zwitterionic polymerization Copolymerization between nucleophilic and electrophilic comonomers. 

Polymers produced by chain-reaction polymerization Copolymerization Kinetics... 

Dreyfuss, P. andM. P. Dreyfuss, Cationic Ring-Opening Polymerization Copolymerization, Chap. 53 in Comprehensive Polymer Science, Vol. 3, G. C. Eastmond, A. Ledwith, S. Russo, and P. Sigwalt, eds., Pergamon Press, London, 1989. 

Ethylene, isobutylene, tert-butylethylene, and other olefins also copolymerize with thiocarbonyl fluoride. What is astonishing is that tetramethylethylene, which is so sterically hindered as to be unreactive in olefin polymerizations, copolymerizes readily with thiocarbonyl fluoride. Most of these comonomers do not behave in the same way as propylene. They give products with compositions more closely approximating the monomer mixture used. 

N (3-Ethynyl phenyl maleimide is synthesized from 3-ethynylaniline and maleic anhydride in DMAc. The cyclodehydration of the resulting amide acid is performed in the usual way with acetic anhydride and nickel acetate as a base catalyst (138). This AB-type monomer has a melting point of 129-131 °C. The polymerization/copolymerization is extremely exotherm (720 J/g) and proceeds in the 180-220 °C temperature range. Furthermore, JV-(3-ethynyl... 

Inoue, S. and Aida, T., Anionic Ring-opening Polymerization Copolymerization , in Comprehensive Polymer Science, Pergamon Press, Oxford, 1989, Vol. 3, pp. 533-569. 

Comparison of the Two Reactions Step-Growth Polymerization in More Detail Making PET in the Melt Interfacial Poly condensation Chain-Growth Polymerization in More Detail Free Radical Chain Polymerization Going One Step Better Emulsion Polymerization Copolymerization Ionic Chain Polymerization It Lives ... 

The polymerization described so far is homo-polymerization based on single monomers. Some polymers used in pharmaceutical applications are copolymers. They have properties that each homo-polymer does not exhibit. For example, the copolymer of hydroxyethyl methacrylate and methyl methacrylate is synthesized in order to obtain a polymer exhibiting a hydrophilic/hydrophobic balance. A variety of copolymers (alternating, block, random) can be formed from two different monomers. Special processes produce alternating and block copolymers, while random copolymers are produced by free-radical copolymerization of two monomers. The polymerization steps, such as initiation, propagation, and termination, are the same as in free-radical homo-polymerization. Copolymerization kinetics are depicted as follows ... 

Now we come to a subject where we will employ what we have learned in applying both kinetics and statistics to polymerizations copolymerization. In our discussion of chain microstructure, we have already discussed the various types of copolymers that can be formed, and these are illustrated in Figure 6-1. We ll start by briefly considering some examples, to give you a feel for the range of materials produced commercially. 

Polymerization, Copolymerization, and Grafting. In this work we have prepared vinyl and isopropenyl derivatives of 2(2-hydroxyphenyl)2H-benzotriazoles 2H5V, 2H5P, and 2(2-hydroxy-5-methylphenyl)2H-4 — vinyl-benzotriazole 2H5V and 2(2-hydroxy-5-methylphenyl)2H-4-vinyl-benzotriazole were hcanopolymerized and copolymerized with styrene,... 

Since 4,7-dihydro-l,3-dioxepin (IA) is both the simplest and one of the more easily prepared 1,3-dioxepin monomers (Table I), copolymerization of equimolar mixtures of IA-MA were first examined under a variety of conditions (Table II). As shown, yields of 1 1 alternating IA-MA copolymer are highly dependent upon polymerization conditions, with highest conversions obtained in 1,2-dichloroethane solvent. Also, incremental or controlled addition of initiator improves yields of copolymer. Using DCE solvent, the copolymers precipitated during polymerization. Copolymerization without added initiator was not observed. 

Polymerization/copolymerization of monocyclic carbonates that also have unsaturated bonds ... 

Polymerization/copolymerization of unsaturated monocyclic carbonates is one of the methods of synthesizing polycyclic carbonates. The copolymerization behavior... 

It is noteworthy that reprocessing of either PEST, PC, or their mixtures can be facilitated by adding 0.2-0.5 wt% of titanium and zirconium esters that re-polymerize, copolymerize and bond these polyesters to fibers, flakes or rubber crumbs. The method has been successfully used to blend 80% recycled PET with recycled PC. The agent is re-activated every time the mixture is reprocessed, thus the alloy s properties improve during recycling [Schut, 1996]. 

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