Free radical polymerization terpolymers

PNIPAAm terpolymers were obtained by free radical polymerization of NIPAAm, DMAAm, and DMIAAm (Scheme 2). Polymerization was initiated by AIBN using 1,4-dioxane as a solvent. DMAAm content was varied from 5 to 50 mol %. The total monomer concentration was 0.55 mol/L and the reaction was carried out at 70 °C for... 

In addition to blending with SPMI copolymers, PMI can be incorporated into ABS using mass, emulsion [46-50] or suspension [42] free radical polymerization techniques. The high heat ABS resin can be completely produced by mass polymerization, or mass polymerized PMI-SAN can be blended with (emulsion polymerized) SAN-grafted rubber concentrates and/or conventional mass ABS. Sumitomo Naugatuck determined an empirical relation for the compatibility of SAN/SAN-PMI blends based on the polar monomers in each component [51]. Figure 15.4 shows that the miscibility window with SANs becomes wider with increasing PMI level in the terpolymer [52]. 

Polymerization Catalysed by Acids and Bases. Carbonium ions and carbanions respectively are carriers of the chain transfer in cationic and anionic polymerizations respectively. Ionic polymerization mechanism was exploited for the synthesis of polymeric stabilizers in comparison with the free-radical polymerization only exceptionally. The cationic process was used for the synthesis of copolymers of 2,6-di-tert-butyl-4-vinylphenol with cyclopentadiene and/or for terpolymers with cyclopentadiene and isobutylene [109]. System SnCWEtsAlCla was used as an initiator. Poly(lO-vinylphenothiazin) was prepared by means of catalysis with titanium chlorides [110]. Polymers of 4-[a-(2-hydroxy-3,5-dimethylphenyl)ethyl]-vinylbenzene [111] and 3-allyl-2-hydroxyacetophenone [112] were also prepared under conditions of cationic polymerization. 

Example 10.2 Discuss the Terpolymer Composition Curves for the Termonomer Systems Acrylonitrile-Styrene-Alphamethyl-Styrene by Free Radical Polymerization in a CSTR... 

K. R. Sharma, Subcritical Damped Oscillatory Concentration in Free Radical Polymerization of Alphamethylstryene, Acrylonitrile and Methacrylonitrile Terpolymer, 229th ACS National Meeting, San Diego, CA, March 2005. 

Dyads and triads in copolymers Free radical polymerization Geometric distribution Dyads and triads in terpolymers Nncleotide sequences in DNA Amino acid sequences in protein Sequence alignment... 

The chain sequence length distribution of DNA can be represented using the geometric distribution. The mean and variance of the geometric distribution would be expected to depend on the mechanism of formation of polynucleotide sequences. For instance, a terpolymer formed hy free radical polymerization can be modeled with respect to the sequence distribution as follows. Let three termonomers enter a long copolymer chain atMj, M2, and M3 concentrations with reactivity ratios r 2, 21, r23, r 2, 13, 31- Assume that the bond formation order does not matter in the rate, that is,... 

The synthesis of the diazosulfonate terpolymer via free radical terpolymerization is described in ref. 10. Amino terpolymers were synthesized by free radical polymerization of the three monomers MMA, 3-(triethoxysilyl)propylmethacrylate and the N-NVOC-aminopropyl-methacryl-amide (equimolar amounts) in dioxane at 75°C for 70 h as described in ref. 11. The protection of the amino monomer has been carried out according to the literature (12). 

Polyacrylonitrile (PAN) is formed by the peroxide-initiated free-radical polymerization of acrylonitrile (CH2=CH—CN). The major application of PAN is as the fiber Orion. When copolymerized with butadiene, it forms Buna N or nitrile rubber, which is resistant to hydrocarbons and oils. As a copolymer with styrene (SAN), it is a transparent plastic with very good impact strength used for machine components and for molding crockery. As a terpolymer of acrylonitrile-butadiene-styrene (ABS), the plastic is known for its toughness and good strength and finds applications in water lines and drains. 

Durmaz, H., Kaiatas, F., Tunca, U., and Hizal, G. (2(X)6b) Preparation of ABC miktoarm star terpolymer containing polyfethylene glycol), polystyrene, and poly(tert-butylacrylate) arms by combining Diels-Alder reaction, atom transfer radical, and stable free radical polymerization routes. Journal of Polymer Science Part A-Polymer Chemistry, 44,499. 

Photochemical cross-linking of DMI-functionalized polymers provides an efficient way to synthesize hydrogels in a selective and controlled manner. By the use of DMI as the chromophore, photocross-linkable copolymers based on NIPAAm and other monomers can be easily synthesized by free-radical polymerization. Phase transition temperatures of the soluble PNIPAAm copolymers can be adjusted between 24.7 and 58.5 °C by changing the amount of chromophore bearing monomer (more hydrophobic) and/or a hydrophilic comonomer. Photocross-linkable co- and terpolymers can be both pH and temperattrre responsive. The transition tem-perattues of the films show similar trends to those of the corresponding linear polymers, and this can be explained in terms of a balance between hydrophobic and hydrophilic side groups in the polymer gel and the osmotic contribution of ionizable comonomers. These polymers could be efficiently converted into gel networks by UV irradiation in the... 

The polymerization of a mixture of more than one monomer leads to copolymers if two monomers are involved and to terpolymers in the case of three monomers. At low conversions, the composition of the polymer that forms from just two monomers depends on the reactivity of the free radical formed from one monomer toward the other monomer or the free radical chain of the second monomer as well as toward its own monomer and its free radical chain. As the process continues, the monomer composition changes continually and the nature of the monomer distribution in the polymer chains changes. It is beyond the scope of this laboratory manual to discuss the complexity of reactivity ratios in copolymerization. It should be pointed out that the formation of terpolymers is even more complex from the theoretical standpoint. This does not mean that such terpolymers cannot be prepared and applied to practical situations. In fact, Experiment 5 is an example of the preparation of a terpolymer latex that has been suggested for use as an exterior protective coating. 

Terpolymers made from two different olefins and CO are known. They were first described in Brubaker s initial patent and involved the free radical initiated terpolymerization of CO and C2H with another olefin such as propylene, isobutylene, butadiene, vinyl acetate, diethyl maleate or tetrafluoroethylene More recently, in another patent, Hammer has described the free radical initiated terpolymerization of CO and C2H with vinyl esters, vinyl ethers or methyl methacrylate 26Reaction temperatures of 180-200 °C and a combined pressure of 186 MPa were employed. Typically a CO QH4 olefin molar ratio of 10 65 25 was observed in the terpolymers. In other patents, Hammer 27,28) has described the formation of copolymers with pendant epoxy groups by the free radical initiated polymerization of CO, QH4, vinyl acetate and glycidyl methacrylate. Reaction conditions similar to those stated above were employed, and a typical CO C2H vinyl acetate glycidyl methacrylate molar ratio of 10 65 20 5 was observed in the product polymer. 

Commercial ABS is prepared primarily by free-radical emulsion copolymerization of styrene and acrylonitrile in the presence of polybutadiene latex (3). This method was therefore adapted for the preparation of ABS and MBS terpolymers and an intermediate AMBS tetrapolymer under similar conditions (Table I). Polymerizations were charged into 12-ounce crown-cap bottles, sparged and flushed with nitrogen, and... 

During weathering, phenolic antioxidants are photooxidized into hydroperoxycy-clohexadienones, such as 59 (Pospisil, 1993 Pospisil, 1980). The presence of peroxidic moieties in 57 and 59 renders them thermolabile at temperatures exceeding 100 °C and photolysable under solar UV radiation. Both processes account for homolysis of the peroxidic moieties. As a result, the oxidative degradation of the polymeric matrix is accelerated by formed free-radical fragments (tests were performed with atactic polypropylene and acrylonitrile-butadiene-styrene terpolymer (ABS) (PospiSil, 1981 PospiSil, 1980). Low-molecular-weight products of homolysis, such as 60 to 63 are formed in low amounts. 

Styrene is frequently used as part of some terpolymers with large practical utilization. One such copolymer is acrylonitrile-butadiene-styrene terpolymer (ABS). Usually it is made as poly(l-butenylene-graft-l-phenylethylene-co-cyanoethylene). This form of the copolymer can be made by grafting styrene and acrylonitrile directly on to the polybutadiene latex in a batch or continuous emulsion polymerization process. Grafting is achieved by the free-radical copolymerization of styrene and acrylonitrile monomers in the presence of polybutadiene. The degree of grafting is a function of the 1,2-vinyl content of the polybutadiene, monomer concentration, extent of conversion, temperature and mercaptan concentration (used for crosslinking). The emulsion polymerization process involves two steps production of a rubber latex and subsequent polymerization of styrene and acrylonitrile in the presence of the rubber latex to produce an ABS latex. 

Earlier references to these terpolymers (SOa/olefin/caibon monoxide) are known. For example, U.S. Patent 2,634,254 discloses the terpolymer prepared by polymerization in the presence of a free radical catalyst such as an azo compound. Also, U.S. Patent 4,251,340 discloses similar terpolymers prepared using irradiation as the initiator. These terpolymers are generally high melting (m.p. about 280°C) and show good structural durability for high temperature applications. 

Acrylamide monomer is a white crystal, available commercially as a 50 wt % aqueous solution. Acrylamide monomer can be polymerized to a very-high-molecular-weight (lO -lO g/mole) homopolymer, copolymer, or terpolymer. Polyacrylamide (PAM) is a nonionic polymer. The anionic polyacrylamide species can be obtained from the hydrolysis of the amide (—CONH ) functional group of the homopolymer, or from the copolymerization of acrylamide with an anionic monomer, such as acrylic acid (AA) or 2-acrylamino 2-methyl propane sulfonic acid (AMPS). Acrylamide can be copolymerized with a cationic monomer, such as dimethyl diallylammonium chloride (DMDAAC) or acryloyloxyethyl trimethyl ammonium chloride (AETAC), to form the cationic acrylamide polymer. Acrylamide can simultaneously react with anionic and cationic monomers to form a polyampholyte. The acrylamide homopolymer, copolymers, and terpolymers are synthesized (1-20) by free radicals via solution or emulsion or other polymerization methods. F. A. Adamsky and E. J. Beckman (21) reported the inverse emulsion polymerization of acrylamide in supercritical carbon dioxide. The product classes of acrylamide polymers include liquid, dry, and emulsion. 

This methodology was also employed for the synthesis of ABC triblock terpolymer of L-lactide (LL), N, N-dimethylacrylamide (AAm), and St. Degradation of the PEL segment of the block copolymer resulted in the formation of nanoporous material.In the synthetic process, first anionic polymerization of lactide initiated by benzyl alcohol in the presence of triethyl aluminum yielded PEL with hydroxyl terminus, which was converted to a CTA with the aid of thionyl chloride. The macro-CTA was then utilized in the successive polymerization of AAm and St in the presence of a free radical source generating a triblock copolymer, PEE-l -PAAm-l7-PSt (Scheme 46). 

The chain addition polymerizations require monomers with double bonds. They require free radical or ionic initiators to open the double bond and form the polymerization path in the manufacture of polymers such as polyethylene, polypropylene, polystyrene, and polyvinyl chloride which together constitute the majority of polymers, about 70 % of all polymers produced. A wide range of copolymers or terpolymers are produced by chain addition polymerization of two or three different monomers with double bonds. 

Polymer synthesis. The synthesis of linear terpolymers of NIPAAm, BMA and AA, with feed ratio of NIPAAm/BMA/AA = 85/5/10 or 80/10/10, was carried out in varying volume percent of benzene and tetrahydrofuran (THF) as solvent. AIBN was used as free radical initiator (7.41 mmol AIBN per mol monomer). Dried N2 gas was bubbled through the solution for 20 min to remove dissolved oxygen. The solution was polymerized for 24 hours at 60 C under N2 atmosphere. The synthesized terpolymers were recovered by precipitation in diethylether. The polymers were filtered and dried under vacuum overnight. 

Major commercial synthetic specialty polymers are made by chain-growth polymerization of functionalized vinyl monomers, carbonyl monomers, or strained ring compounds. Depending on monomer structure, the polymerization may be initiated free radically, anionically, or cationically. Copolymers or terpolymers with random, alternating, block, or graft sequences can be prepared under appropriate reaction conditions. There are numerous mediods used to prepare specialty polymers in the research laboratory. However, only a few are of commercial interest. Of particular commercial interest is synthesis of specialty polymers in solutions, dispersions, suspensions, or emulsions. 

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