Vinyl chloride/methyl methacrylate

The applicability of various types of initiation mechanisms to the polymerization of common olefin monomers is summarized in Table 8.1. We see that isobutene can be polymerized only by cationic initiation, whereas monomers, such as vinyl chloride, methyl methacrylate or acrylonitrile with their electronegative substituents will not yield at all to cationic initiation. Vinyl chloride, however, does not respond to anionic initiation as well. Though halogens can withdraw electrons inductively and push electrons by resonance, both effects are relatively weak. Vinyl chloride thus does not undergo either anionic or cationic polymerization. 

VCMMA vinyl chloride/methyl methacrylate VR viscosity ratio... 

Copolymers of acrylonitrile and lower acrylates have also been used as thickeners. The proportion of the acrylate in the copolymer was 60-90% by weight the preferred acrylates were the methyl through butyl esters. These authors also tested an extensive list of known and novel thickeners as comparative examples. The latter included nitrile rubber and vinyl acetate-vinyl chloride, methyl methacrylate-butadiene-styrene (MBS), and acrylonitrile-butadiene-styrene (ABS) copolymers. The copolymers of this invention were claimed to provide better stability, higher viscosity, less stringing, and better impact strength than do the thickeners of the prior art. The claims of this patent do not cover the disclosed copolymers. Polyvinyl ethers are another class of cyanoacrylate thickeners which have been disclosed but not claimed. ... 

Block Copolymers. Several methods such as ultrasonics (100), radiation (101), and chemical techniques (102,103), including the use of polymer ions, polymer radicals, and organometallic initiators, are available to prepare Block Copolymers of acrylonitrile. Acrylonitrile can be used as either the first-or the second-phase monomer. Depending on the mechanism of termination, a diblock of the AB type and a triblock of the ABA type can be formed by disproportionation or transfer for the former, and recombination for the latter. Some of the comonomers are styrene, methyl acrylate, vinyl chloride, methyl methacrylate, vinyl acetate, acrylic acid, and re-butyl isocyanate. An overview and survey of alternating and block copolymers can be found in Reference 104. 

VCMMA (Vinyl chloride)-(methyl methacrylate) plastic... 

Attempts have been made to prepare stereoreguiar polymers from polar monomers (e.g. vinyl chloride, methyl methacrylate) using modified Ziegler-Natta catalysts, but without success. When polymerization does occur it yields non-stereospecific polymer and is thought to proceed by free-radical mechanisms. 

Vinyhdene chloride copolymerizes randomly with methyl acrylate and nearly so with other acrylates. Very severe composition drift occurs, however, in copolymerizations with vinyl chloride or methacrylates. Several methods have been developed to produce homogeneous copolymers regardless of the reactivity ratio (43). These methods are appHcable mainly to emulsion and suspension processes where adequate stirring can be maintained. Copolymerization rates of VDC with small amounts of a second monomer are normally lower than its rate of homopolymerization. The kinetics of the copolymerization of VDC and VC have been studied (45—48). 

Modifications of epichlorohydrin elastomers by radical-induced graft polymeri2ation have been reported. Incorporated monomers include styrene and acrylonitrile, styrene, maleic anhydride, vinyl acetate, methyl methacrylate, and vinyHdene chloride (81), acryHc acid (82), and vinyl chloride (81,83,84). When the vinyl chloride-modified epichlorohydrin polymers were used as additives to PVC, impact strength was improved (83,84). 

For ambient or low temperature application, thermoplastic polymers can be used. Low cost monomers that have been used in this category include ethylene, ethylene-S02, vinyl acetate, methyl methacrylate, styrene, styrene-acrylonitrile, and chlorostyrene. Others awaiting test are vinyl chloride, vinylidene chloride, and terf-butylstyrene. These monomers are limited for use at temperatures below / 100°C because of their softening points. 

Fig. 22a-h. Glass transition temperature versus composition of copolymers methyl methacrylate + styrene (a) styrene + methyl acrylate (b) acrylonitrile + styrene (c) vinyl chloride + methyl acrylate (d) methyl methacrylate + vinyl chloride (e) acrylonitrile + butadiene (f) acrylonitrile + vinyl acetate (g) a-methyl styrene + acrylonitrile (h). Experimental points obtained at low conversions from various publications, are compared to the theoretical plots calculated according to Eqs. (7.1) within the framework of the terminal model [18]... 

The above calculations explain well the qualitative results with monomers like vinyl chloride, vinyl acetate, methyl methacrylate, and styrene. Quantitatively, the correlation between theory and experiment will depend on the magnitude of d and x, which may also change during the formation period. Generally, if Z> 0.6, the particle number, as well as the value of Z,... 

COz. propene, acetaldehyde, vinyl chloride, ethyl chloride, methyl methacrylate... 

This synthetic method has two steps the first step involves synthesising the polymer and the second includes modification with active groups. Some monomers generally used to form the backbone of homopolymers or copolymers include vinyl benzyl chloride, methyl methacrylate, 2-chloroethyl vinyl ether, vinyl alcohol and maleic anhydride. The polymers are then activated by anchoring antimicrobial groups, such as phosphonium salts, ammonium salts or phenol groups, via quaternisation, chloride substitution or anhydride hydrolysis. 

The NMR method has been extremely successful when applied to sequencing addition copolymers with carbon atom backbone, such as ethylene, propylene, butadiene, acrylonitrile, vinyl acetate, methyl methacrylate, styrene, methylstyrene, vinyl chloride, vinyl fluoride (in this case, F-NMR can be used). " Condensation copolymers such as polyurethanes, polyesters, and polyamides have been analyzed by and NMR. cellent reviews have appeared on this topic, the literature on the subject is always growing, and the instrumental progress is fast. ... 

Methyl acrylate Ethyl acrylate Butyl acrylate Dodecyl acrylate Methyl methacrylate Butyl methacrylate Octyl methacrylate Dodecyl methacrylate Acrylonitrile Vinyl acetate Vinyl stearate Vinyl pelargonate Methyl vinyl ether Ethyl vinyl ether Octyl vinyl ether Dodecyl vinyl ether Vinyl chloride Vinyl bromide Vinyl iodide Methyl acrylate Butyl acrylate Octyl acrylate Dodecyl acrylate Octadodecyl acrylate Maleic anhydride Tetrachloroethylene Methyl methacrylate Butyl methacrylate Octyl methacrylate Vinyl chloride Vinyl chloride Ethyl vinyl ether Butyl vinyl ether Heptyl vinyl ether Hexadecyl vinyl ether Methyl methacrylate Butyl methacrylate Heptyl methacrylate Hexadecyl methacrylate Maleic anhydride Vinyl acetate Methyl acrylate Methyl methacrylate Diethyl maleate... 

Methyl acrylate Acrylonitrile Methyl methacrylate Vinyl acetate Vinyl stearate Vinyl pelargonate Vinyl acetate Methyl methacrylate n-Butyl methacrylate n-Octyl methacrylate Methyl acrylate n-Butyl acrylate n-Octyl acrylate Vinyl chloride Vinyl bromide Vinyl iodide T etrachloroethy lene Maleic anhydride Maleic anhydride... 

Other vinyl polymers that have heen examined include vinylidene chloride — methyl methacrylate [76], vinylidene chloride — phenyl acetate [77], vinyl chloride — butadiene [78], vinyl copolymers [79] and vinylidene chloride - polyethylene [80]. 

Polymerization reactions can also be classified in terms of the reaction medium, and the principal types are bulk, solution, slurry, emulsion, and gas-phase. In bulk polymerization, the reactor initially contains only monomer, and the product is a viscous melt. This is the type of system usually used for step (condensation) polymers. In solution polymerization, both the monomer and the polymer are soluble in the solvent, while in emulsion and slurry reactors, the polymer is not soluble in the reaction medium, which is called a diluent. The principal monomers polymerized by means of emulsion polymerization are vinyl acetate, methyl methacrylate, and vinyl chloride. In a gas-phase reactor or slurry reactor, the gaseous monomer is polymerized on the surface of catalyst particles, which are supported either by stirring in a horizontal reactor, or by fluidization in a vertical reactor. Slurry and gas-phase reactors are used primarily to make polyolefins. 

Vinyl chloride Alkyl methacrylate Methyl methacrylate Vinyl chloride... 

Table I compares the important physical properties of the currently used acrylic resin denture bases - the heat cured and self cured bases. These are typically powder/liquid mixtures containing benzoyl peroxide redox systems activated by a tertiary aromatic amine. Among these are the vinyl chloride - vinyl acetate - methyl methacrylate mixtures and the newer pour type denture bases - the latter designed for laboratory convenience and model fit by control of polymerization shrinkage. On this half of the table the important comparative properties are transverse deflection, failure and water sorption.

Properties Poly(methyl methacrylate) Cast sheet Impact- modified Heat- resistant Alkyd, molded Acrylic poly(vinyl chloride) alloy ... 

Figure 9.17 Plot of log [i ]M versus retention volume for various polymers, showing how different systems are represented by a single calibration curve when data are represented in this manner. The polymers used include linear and branched polystyrene, poly(methyl methacrylate), poly(vinyl chloride), poly(phenyl siloxane), polybutadiene, and branched, block, and graft copolymers of styrene and methyl methacrylate. [From Z. Grubisec, P. Rempp, and H. Benoit, Polym. Lett. 5 753 (1967), used with permission of Wiley.]...

Uses. The a2obisnitriles have been used for bulk, solution, emulsion, and suspension polymeri2ation of all of the common vinyl monomers, including ethylene, styrene vinyl chloride, vinyl acetate, acrylonitrile, and methyl methacrylate. The polymeri2ations of unsaturated polyesters and copolymeri2ations of vinyl compounds also have been initiated by these compounds. 

Other Polymers. Besides polycarbonates, poly(methyl methacrylate)s, cycfic polyolefins, and uv-curable cross-linked polymers, a host of other polymers have been examined for their suitabiUty as substrate materials for optical data storage, preferably compact disks, in the last years. These polymers have not gained commercial importance polystyrene (PS), poly(vinyl chloride) (PVC), cellulose acetobutyrate (CAB), bis(diallylpolycarbonate) (BDPC), poly(ethylene terephthalate) (PET), styrene—acrylonitrile copolymers (SAN), poly(vinyl acetate) (PVAC), and for substrates with high resistance to heat softening, polysulfones (PSU) and polyimides (PI). 

MBS polymers are prepared by grafting methyl methacrylate and styrene onto a styrene—butadiene mbber in an emulsion process. The product is a two-phase polymer useful as an impact modifier for rigid poly(vinyl chloride). 

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