Radical-polymerized poly

Kratochvii, P., M. BOHDANECKf, K. Sole, M. Kor.fNsirf, M. Ryska, and D. l.fM On the structure and solution properties of radically polymerized poly (vinyl chloride). International Symposium on Macromolecular Chemistry Preprints, Vl-69 (1966). 

Keywords acrylate- and methacrylate guanidines radical polymerization poly (meth) acrylate guanidines, conformational behavior, micro-heterogeneity... 

FIGURE 18. Fluorescence spectra of radically polymerized poly(N-vinylcarbazole) films at 293 and 77°K. (1) 29TOK total, (2) 77°K total, (3) component... 

Alternating ABABABABABABABABAB Styrene, maleic anhydride Free-radical polymerization Poly(styrene-a/f-maleic anhydride)... 

The first studies of this problem were carried out on poly(styrene). For example, in the pyrolysis of radically polymerized poly(styrene), 1,3-diphenylpropane and 1,3,5-triphenylpentane were recovered, but no diphenylethane. Small proportions of 1,1 linkages could not be found since the pyrolysis products could not be recovered quantitatively, and the method of determination was not very sensitive. 

The proportion of head-to-head structures can be considerable in some cases. For example, in free-radical-polymerized poly(vinylidene fluoride), -fOH2—CF2 fi, there are about 10-12% of such links according to nuclear magnetic resonance measurements ( H and F). The proportion is as high as 6-10% in poly(vinyl fluoride). Admittedly, these physical methods... 

The molecular weight of each component in a polymer blend may also be determined. In a model experiment, poly(methyl methacrylate), PMMA, molecular weights were estimated in the presence of polystyrene, PS (90). Anion-ically polymerized polystyrene and free radically polymerized poly(methyl methacrylate) were dissolved in tetrahydrofuran in a 50/50 w/w mix. A dual detector GPC was used, equipped with refractive index (RI) and ultraviolet (UV) detectors. 

A detailed photoconductivity study has been carried out with a number of polymethacrylates with pendant aromatic amino groups [93]. Among seven polymethacrylates that have been synthesized from the corresponding methacrylate monomers by free-radical polymerization, poly(2-(N-ethyl-N-3-tolylamino)ethyl methacrylate (18a) and poly((4-diphenylamino)phenylmethylmethacrylate) (18b) exhibit carrier mobilities that exceed the values of PVK by about one order of magnitude at all electric fields. 

The method lends itself to a demonstration of the fact that certain poly(methyl methacrylate) polymers are block copolymers of isotactic and syndiotactic conformation, not to mention that conventional, i,e., free-radically polymerized, poly(methyl methacrylate) contains a substantial fraction of the isotactic polymer. 

An extension of the substituted thiophene work involved the incorporation of methacrylate functionality onto the thiophene backbone [84,85]. Methacrylates are widely known to undergo free radical polymerizations. Poly(12-(methacryloyloxy)ethyl)thiophene) as well as... 

It is also known that syndiotactic poly-(methylmethacrylate) is obtained by low temperature radical polymerization poly-(methylmethacrylate) with optical rotatory power of [a] D + 0.7 1.4° was obtained by polymerization at 0 20 °C using a borneol/ Ce type optically active initiator [25], but the polymer obtained at 70 100°C was... 

As the demand for rubber increased so did the chemical industry s efforts to prepare a synthetic sub stitute One of the first elastomers (a synthetic poly mer that possesses elasticity) to find a commercial niche was neoprene discovered by chemists at Du Pont in 1931 Neoprene is produced by free radical polymerization of 2 chloro 1 3 butadiene and has the greatest variety of applications of any elastomer Some uses include electrical insulation conveyer belts hoses and weather balloons... 

Hydroxy-2-methylpropanenitrile is then reacted with methanol (or other alcohol) to yield methacrylate ester. Free-radical polymerization is initiated by peroxide or azo catalysts and produce poly(methyl methacrylate) resins having the following formula ... 

Poly (methyl Acrylate). The monomer used for preparing poly(methyl acrylate) is produced by the oxidation of propylene. The resin is made by free-radical polymerization initiated by peroxide or azo catalysts and has the following formula ... 

Emulsion Adhesives. The most widely used emulsion-based adhesive is that based upon poly(vinyl acetate)—poly(vinyl alcohol) copolymers formed by free-radical polymerization in an emulsion system. Poly(vinyl alcohol) is typically formed by hydrolysis of the poly(vinyl acetate). The properties of the emulsion are derived from the polymer employed in the polymerization as weU as from the system used to emulsify the polymer in water. The emulsion is stabilized by a combination of a surfactant plus a coUoid protection system. The protective coUoids are similar to those used paint (qv) to stabilize latex. For poly(vinyl acetate), the protective coUoids are isolated from natural gums and ceUulosic resins (carboxymethylceUulose or hydroxyethjdceUulose). The hydroHzed polymer may also be used. The physical properties of the poly(vinyl acetate) polymer can be modified by changing the co-monomer used in the polymerization. Any material which is free-radically active and participates in an emulsion polymerization can be employed. Plasticizers (qv), tackifiers, viscosity modifiers, solvents (added to coalesce the emulsion particles), fillers, humectants, and other materials are often added to the adhesive to meet specifications for the intended appHcation. Because the presence of foam in the bond line could decrease performance of the adhesion joint, agents that control the amount of air entrapped in an adhesive bond must be added. Biocides are also necessary many of the materials that are used to stabilize poly(vinyl acetate) emulsions are natural products. Poly(vinyl acetate) adhesives known as "white glue" or "carpenter s glue" are available under a number of different trade names. AppHcations are found mosdy in the area of adhesion to paper and wood (see Vinyl polymers). 

Allyl polymers are made by free-radical polymerization of diaHyl compounds, most frequently diallyl dimethyl ammonium chloride (DADMAC) [7398-69-8] forming a chain containing a five-membered ring (28) poly(DADMAC) [26062-79-3]. 

The nmr spectmm of PVAc iu carbon tetrachloride solution at 110°C shows absorptions at 4.86 5 (pentad) of the methine proton 1.78 5 (triad) of the methylene group and 1.98 5, 1.96 5, and 1.94 5, which are the resonances of the acetate methyls iu isotactic, heterotactic, and syndiotactic triads, respectively. Poly(vinyl acetate) produced by normal free-radical polymerization is completely atactic and noncrystalline. The nmr spectra of ethylene vinyl acetate copolymers have also been obtained (33). The ir spectra of the copolymers of vinyl acetate differ from that of the homopolymer depending on the identity of the comonomers and their proportion. 

Emulsion Polymerization. Poly(vinyl acetate)-based emulsion polymers are produced by the polymerization of an emulsified monomer through free-radicals generated by an initiator system. Descriptions of the technology may be found in several references (35—39). 

Water-soluble polymers obtained through a radical polymerization [e.g., poly(acrylic acid) PAA] often contain sodium sulfate Na2S04 as a decomposition product of the initiator. The peak of Na2S04 is eluted before the dimer. In the interpretation of the chromatogram, a typical GPC program has to be truncated before the Na2S04 peak, or at a Mpaa value of about 200. The calibration curve in this region can be flattened by an additive small pore column as well, but the principle problem remains unsolved. 

Acrylamide readily undergoes polymerization by conventional free radical methods, ionizing radiation, ultrasonic waves, and ultraviolet radiation. The base-cata-lized hydrogen transfer polymerization of acrylamide yields poly-/3-alanine (Nylon 3) a water insoluble polymer that is soluble in certain hot organics. All current industrial production is believed to be by free radical polymerization. 

Mn2(CO)io in a simple photoinitiated free radical polymerization. The antiplatelet activity of these polymers were compared with that of poly(ether-Wrethane) carrying the hydantoin residues in side chains. 

The structure-property relationship of graft copolymers based on an elastomeric backbone poly(ethyl acry-late)-g-polystyrene was studied by Peiffer and Rabeony [321. The copolymer was prepared by the free radical polymerization technique and, it was found that the improvement in properties depends upon factors such as the number of grafts/chain, graft molecular weight, etc. It was shown that mutually grafted copolymers produce a variety of compatibilized ternary component blends. 

There are some indications that the situation described above has been realized, at least partially, in the system styrene-methyl methacrylate polymerized by metallic lithium.29 29b It is known51 that in a 50-50 mixture of styrene and methyl methacrylate radical polymerization yields a product of approximately the same composition as the feed. On the other hand, a product containing only a few per cent of styrene is formed in a polymerization proceeding by an anionic mechanism. Since the polymer obtained in the 50-50 mixture of styrene and methyl methacrylate polymerized with metallic lithium had apparently an intermediate composition, it has been suggested that this is a block polymer obtained in a reaction discussed above. Further evidence favoring this mechanism is provided by the fact that under identical conditions only pure poly-methyl methacrylate is formed if the polymerization is initiated by butyl lithium and not by lithium dispersion. This proves that incorporation of styrene is due to a different initiation and not propagation. 

Takemoto et al.21) synthesized similar types of models, i. e. poly(/3-methacryl-oyloxyethyladenine) 20 (PMAOA), poly(0-methacryloyloxyethyluracil) (PMAOU), and poly(j3-methacryloyloxyethylthymine) (PMAOT), by free-radical polymerizations of /3-methacryloxyethyl compounds of the corresponding base. 

Poly(isoprene) can also he prepared by radical polymerization/ 17 Although the ratio of l,4- l,2- 4,3- units is stated to be ca 90 5 5 irrespective of the polymerization temperature (range -20-50 °C), the proportion of cis-1,4-addition increases from 0 at -20 °C to 17.6% at 50 °C. EPR studies indicate that radicals add preferentially to the 1-position.87... 

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