Acryl-type monomers

The high pressure polymerization of ethylene can be slightly modified for the copolymerization of ethylene with vinyl- and acrylic-type monomers such as vinyl acetate, vinyl chloride, acrylonitrile, or acrylic esters. Some of these copolymers of ethylene and vinyl acetate or maleic anhydride are already available and have found various applications in plastics, coatings, and adhesives. Copolymers of ethylene and vinyl chloride and of ethylene and acrylonitrile appear particularly interesting because of the low cost of monomers and the properties of the copolymers. Although their synthesis has been disclosed in a number of patents their larger scale production is still in a state of development. 

Examination of cur data for peaks due to monomer which might be formed from unzipping reactions showed no detectable amount being produced. This is not unexpected because the prepolymer composition is approximately 50% acrylate type monomers and, therefore, degradation by unzipping is unlikely. 

Zwitterionic Polymerizations. Zwitterionic intermediates also appear to be responsible for the spontaneous specific 1 1 copolymerizations of some acrylate-type monomers with cyclic nucleophilic species reported by Saegusa and his CO-workers.In many ways these resemble the spontaneous polymerizations of strong donor and acceptor vinyl moities mentioned earlier. s —... 

Nitroxides have been used to prepare numerous block copolymers. Initially, using the TEMPO moiety, only styrene-based monomers could be incorporated into copolymers, but with the use of new nitroxides like DEPN and BPPN, the list has expanded to include acrylate-type monomers, as well as dienes, something that previously could only be accomplished through ionic mechanisms. Unfortunately, chain extension of either St or diene-based macroinitiator with an acry-... 

The majority of imprinting protocols make use of acryl-type monomers and a range of monomers have been specially developed for these applications. One reason to why this particular strategy has been so widely adopted is because acrylates copolymerizes rather well with other acrylates, and the same goes for acrylamides. Thus, the chances of obtaining a MIP where the distribution of the monomers is not affected by the polymerization per se are substantially greater. 

The molecular weight of a polymer can be controlled through the use of a chain-transfer agent, as well as by initiator concentration and type, monomer concentration, and solvent type and temperature. Chlorinated aUphatic compounds and thiols are particularly effective chain-transfer agents used for regulating the molecular weight of acryUc polymers (94). Chain-transfer constants (C at 60°C) for some typical agents for poly(methyl acrylate) are as follows (87) ... 

The successful development of eye contact lenses led in turn to a demand for soft contact lenses. Such a demand was eventually met by the preparation of copolymers using a combination of an acrylic ester monomer such as methyl methacrylate, a cross-linkable monomer such as a dimethacrylate, and a monomer whose homopolymer is soluble or highly swollen in water such as N-vinyl pyrrolidone. Such copolymers swell in water (hence the term hydrophilic), the degree of swelling being controlled by the specific type and amount of the monomers used. In use the lens is swollen to equilibrium in water, a typical soft lens having a water content of about 75%. 

This polymer contains carboxylic as well as acrylic functionality. The acrylic part of the polymer undergoes light induced polymerization. Use of this photoreactive polymer eliminated the need for separate acrylic type polymerizable monomer(s). 

The initiation of polymerization by ultraviolet radiation has been of particular interest in the study of free radical processes [1,2]. The test tube demonstration described here is simple and may be used to evaluate the polymerizabil-ity of new monomers or to study some of the physical properties of a polymer. Although the method is particularly effective for acrylic and methacrylic monomers, it may also be applied to the polymerization of a wide range of vinyl -type monomers. 

Acrylate types of monomers and oligomers are known to be skin and eye irritants. Even if they do not cause irritation immediately, they may sensitize a person over a longer exposure and cause allergy. On the other hand, they represent much less of a hazard than common solvents (see Table 10.1). 

In general, acrylic ester monomers copolymerizc readily with each other or with most other types of vinyl monomers by free-radical processes. 

Monomer Purification. All polymers were prepared from either column purified or distilled monomers. The acrylate and methacrylate esters, styrene, and vinyl nitrile type monomers were purified by passing them through Rohm and Haas Amberlyst exchange resins (salt forms), while the diene monomers were either distilled directly from cylinders and condensed in a dry ice trap or alternatively caustic washed to remove the inhibitor. 

In general, acrylic ester monomers copolymerize readily with each other or with most other types of vinyl monomers by dee-radical processes. The relative ease of copolymerization for 1 1 mixtures of acrylate monomers with other common monomers is presented in Table 7. Values above 25 indicate that good copolymerization is expected Low values can often be offset by a suitable adjustment in the proportion of comonomers or in the method of their introduction into the polymerization reaction (86). 

Various bifunctional resins are based on acrylic epoxide monomers. Such systems can photopolymerize by the radical and/or cationic mechanism. With iron arene photoinitiators in the presence of an oxidant, radical as well as cationic photopolymerization of these monomers is possible . Onium -type photoinitiators form radical species upon photolysis, as shown in Figs. 3 and 4. The local radical concentration is, however, too low to permit the polymerization of such systems... 

Considerable efforts have been directed, during the last few years, to grafting various vinyl and acrylic monomers on cellulosic fibers or films in order to modify their properties in a predetermined way. It was shown that one can graft large amounts of vinyl-type monomers, such as acrylonitrile or acrylic esters on rayon, cotton, cellophane, paper, and wood, thus modifying the properties of the base material in many respects, and improving, particularly, dimensional stability, water repellency, and resistance to thermal and chemical degradation. 

As prepol3nners used in crosslinking reactions of acrylic enamels are usually copol3nners of acrylic (x = H) and methacrylic (x CH3) type monomers, the macroradlcal I can undergo a number of rearrangements depending on the local sequence distribution. For X = Y CH3 (a methacrylate sequence) one obtains ... 

Subsequently D Alello developed the polystyrene-hased resin in 1944 (4). Two years later, polystyrene anion-exchange resins made hy chloromethylation and amination of the matrix were produced. Four principal classes of ion-exchange resins were commercially availahle by the 1950s. These are the strong-acid, strong-hase, and weak-hase resins derived from styrene-divinylbenzene copolymers, and the weak-acid resins derived from cross-linked acrylics. To this day, the most widely used ion exchangers are synthetic organic polymer resins based on styrene- or acrylic-acid-type monomers as described by D Alelio in U.S. Patent 2,3666,007. 

Polymerizable Ultraviolet Stabilizers — Miscellaneous Types. In our research on polymerizable ultraviolet stabilizers, we have decided to prepare styrene-type monomers in which the vinyl (or isopropenyl) group is directly attached to the phenyl group of the stabilizer, which might be polymerized similarly to styrene. These monomers can indeed be polymerized and copolymerized successfully with styrene, acrylic and methacrylic acid derivatives with azobisisobutyronitrile (AIBN) as the radical initiator (12-Ut-). 

Intermediate species such as macromolecules bearing acrylate-type residues represent a cross between photopolymerizable monomers and photocrosslinkable polymers. The gap between photopolymerizable systems and photocrosslinkable polymers is closed since the two systems are basically the same. A photocrosslinkable polymer can be considered the extreme case of a macromolecular photopolymerizable monomer. 

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