Polymerization copolymer

Copolymers of VDC can also be prepared by methods other than conventional free-radical polymerization. Copolymers have been formed by irradiation and with various organometaHic and coordination complex catalysts (28,44,50—53). Graft copolymers have also been described (54—58). 

Recently, Si et al. [59,60] have investigated the synthesis of polymerizable amines, such as N-(3-dimethyl-aminopropyl) acrylamide(DMAPAA) and N-(3-dimeth-ylaminopropyl) methacrylamide (DMAPMA), and their copolymerization reaction. DMAPAA or DMAPMA in conjunction with ammonium persulfate was used as a redox initiator for vinyl polymerization. Copolymers having amino pendant groups, such as copolymer of... 

Chen B, Metera K, Sleiman HF. Biotin-terminated ruthenium hipyridine ring-opening metathesis polymerization copolymers synthesis and self-assemhly with streptavidin. Macromolecules 2005 38 1084-1090. 

The solution random copolymer generally contains about 32 percent cis-, 41 percent trans- and 27 percent vinyl-unsaturation compared to 8 per cent cis-, 74 percent trans- and 18 percent vinyl-unsaturation in emulsion copolymer of the same monomer composition. The principal effect of slightly higher vinyl unsatura-tion in solution copolymer is a small increase in the glass transition temperature (-58 C versus -62 C for the emulsion copolymer). However, both solution and emulsion polymerized copolymers exhibit satisfactory low temperature performance for general uses. 

Emulsion Polymerization Copolym erization Ionic Chain Polymerization it Lives ... 

The USPNF 23 describes methacrylic acid copolymer as a fully polymerized copolymer of methacrylic acid and an acrylic or methacrylic ester. Three types of copolymers, namely Type A, Type B, and Type C, are defined in the monograph. They vary in their methacrylic acid content and solution viscosity. Type C may contain suitable surface-active agents. Two additional polymers, Type A (Eudragit RE) and Type B (Eudragit RS), also referred to as ammonio methacrylate copolymers, consisting of fully polymerized copolymers of acrylic and methacrylic acid esters with a low content of quaternary ammonium groups, are also described in the USPNF 23. A further monograph for an aqueous dispersion of Type C methacrylic acid copolymer is also defined see Section 9. 

When two different monomers are mixed and then polymerized, copolymers are formed. Depending on the ratio of the two monomers and the reaction conditions, the order of the units can range from quite regular (e.g., alternating) to completely random. In this way, polymers with a wide variety of properties can be produced. The most important rubber produced in the largest amount in the United States is styrene butadiene rubber (SBR), a polymer of styrene with butadiene in a 1 3 molecular ratio. 

Polymerization. Copolymers of tetrafluoroethylene/perfluoro(methyl vinyl ether) and the nitrile (1-4 mole ) have been prepared batch-wise in a stirred autoclave using an aqueous ammonium persulfate or ammonium persulfate-sodium sulfite redox couple system at 40°-100° C. The TFE/PMVE gas mixture was pressured, as required, to maintain the pressure and the nitrile pumped in solution in trichlorotrifluoro-ethane. After completion of the reaction, polymer was isolated from the latex (25-30 solids) by coagulation using ethanol and aqueous magnesium chloride solution. It was washed with alcohol/water solutions and dried at 70 °C in an oven under nitrogen. Mass balance indicated that most of the nitrile had been incorporated. 

These generalizations may be illustrated by example (61). Consider the experiments outlined in Table 1. PHEMA, PMMA and copolymers of the two were prepared by dilute solution polymerization. Copolymer compositions (Table 1A [parentheses] ), obtained by application of proton Nuclear Magnetic Resonance spectroscopy (as detailed later in the discussion), are almost identical to the monomer feed ratios, despite high conversions. The latter increase through series 3 to 1, due to the square root relationship between initiator concentration and instantaneous rate of polymerization (63). Close to random co-polymerizations have been observed also in monomer mixtures containing... 

In contrast to Kucera s data Fejgin et al.138) found that the content of the unstable fraction does not change significantly when the proportion of DXL units increases above 2.5 mol %, Typical results are shown in Table 7.17. Similar results were obtained for the radiation-induced polymerization copolymer prepared from a 95 5 mixture of TXN and DXL still contained 12% of the unstable fraction. 

When the polymerization mixture was heated for a few minutes after the addition of TBA, a bimodal molecular weight distribution was obtained. Part of the polystyrene remained unreacted probably as a result of incomplete initiation of aziridine. The polystyryl ester may decompose e g. by proton transfer before it can initiate TBA polymerization. Copolymer formation may proceed by the following route ... 

Unfed polymerization monomer mixture contained 80 mole % AN and 20 mole % S final product actually contained 23.6 mole % S because the reaction did not go to complete conversion. Fed polymerization copolymer had a uniform composition of 8C mole % AN and 20 mole % S. 

So far, our discussion has been restricted to chain block and graft copolymerization. This is largely because the practical utility of copolymerization is more elaborate in chain polymerization than step polymerization. Also, in step copolymerization, block copolymers are generally preferred to the other types of copolymers. Therefore only block step-polymerization copolymers are discussed here and only in a very limited scope to illustrate the principles involved in their preparation. 

Figure 10-25. Glass transition temperatures Tg of free-radically-polymerized copolymers of styrene and acrylic acid (AS), acrylamide (AA), /-butyl acrylate (BA), and butadiene (BU) as a function of the mole fraction Xsty of styrene monomeric units (after K. H. lllers).

Definition Fully polymerized copolymer of acrylic and methactylic acid esters with a low content of quat. ammonium groups Propertbs Colorless clear to wh.-opaque gran., faint amine odor sol. in methanol, alcohol, I PA, acetone, ethyl acetate, methylene chloride insol. in water, petrol, ether... 

Synonyms Methacrylate copolymer Methacrylate polymer Definition Fully polymerized copolymer of methacrylic acid and an acrylic or methacrylic ester Type C may contain surfactants Properties Wh. powd., faint char, odor sol. in dll. alkali, buffer sol ns. of pFI 7, methanol, alcohol, IPA, acetone insol. in water, dll. acids vise. 50-200 cps... 

Utilizing an electrocopolymerization technique, various conducting copolymer layered structures were constructed. The copol)mier composition, and the thickness of the polymerized copolymer, are controlled easily in the electrolytic polymerization process (Fig. 7). Fig. 8 is an example of such depth profile-controlled multilayers, consisting of polypyrrole and copoly(pyrrole/3-methylthiophene). The present method will allow nm-level thickness control. 

To produce polymer wood, wood is degassed and then loaded according to wood type with 35%-95% monomer. The monomer is then converted by polycondensation or addition polymerization to polymer. For polycondensation, monomers that do not eliminate volatile components during polyreaction are, of course, preferred. Ring-shaped monomers as well as monomers with carbon-carbon double bonds can be polymerized. In the latter case, polymerization can be induced by 7-rays, peroxides, redox systems, etc. Not all monomers, however, are suitable for the preparation of polymer wood. For example, acrylonitrile is not soluble in its own monomer. In wood, therefore, the precipitation polymerization leads to powdery deposits and not to a continuous phase. The same problem occurs with vinyl chloride, and in this case, the boiling point of the monomer is too low. Poly (vinyl acetate) has a glass transition temperature which is too low. In addition, monomers with G values (see Chapter 12) which are too low require high 7-ray doses to induce polymerization. Copolymers of styrene and acrylonitrile, poly (methyl methacrylate), and unsaturated polyesters are used commercially. 

In addition there is a report of a water soluble polymeric (copolymer) photoinitiators. These initiators were synthesized by copolymerizing 2-acryloxy and 2-acrylamido anthraquinone monomers with three water-soluble comonomers acrylamide, 2-acrylamido-2-methylpropane sulfonic acid and 2-acryloxyethyl trimethylammonium iodide. The polymerization activity correlates well with their measured photo reduction quantum yields in water... 

Emulsion polymerized copolymer of butyl acrylate, styrene, acrylic acid, and acrylamide Polyester Stainless steel 42 (24) [39] 190(39] 370 [39] ... 

M. Bakhshaee, R.A. Pethrick, H. Rashid, D.C. Sherrington, Encapsulation of carbon black in suspension polymerized copolymers, Polym. Commun. 1985, 26, 185-192. 

The pol5uner types considered here are primarily those that are soluble in water as prepared, soluble after neutralization of emulsion polymerized copolymers, the so-called alkali-soluble polsrmers, and cross-linked swellable gel polymers. Emulsion polymers are discussed in a limited fashion, as acrylic and methacrylic acids are used ubiquitously at low levels in almost all acrylic emulsion polymerizations to contribute some special characteristic. For example, the incorporation of acidic monomers contributes to such properties as adhesion, wettability, and emulsion polymer stability. 

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