Free radical copolymerizations with styrene

A noticeable change in the TBSM activity as compared with that of its organic analog BMA (rBMA = 0.64 and rSt = 0.54)89) in the free-radical copolymerization with styrene may be ascribed to steric factors and the effect of intermolecular coordination. 

The attachment of preformed polyethereal dendrons (e. g., 70, see Scheme 5.17), which have been functionalized at the focal point by reaction with p-(chloromethyl)sty-rene, has been shown1501 to undergo free radical copolymerization with styrene giving rise to polystyrene with appended benzyl ether dendritic wedges. 

TABLE 2.11 Monomer Reactivity Ratios for Free Radical Copolymerization with Styrene (M ) ... 

PolylStyrene co-n-Butyl Methacrylate) Fractionation. OC was developed with the particular idea of elucidating the kinetics of the free radical copolymerization of styrene n-butyl methacrylate. Thus, this polymer provided the main focus of the work. 

Synthesis of a styrene monomer containing a diiron hexacarbonyl moiety and its copolymer together with the metal atom of the preferred copolymers has been achieved [6]. (3) and (4) (Fig. 2) undergo free radical copolymerization with... 

Kennedy 67,77 118) studied the ability of w-styryl-polyisobutene macromonomers to undergo free-radical copolymerization with either styrene or butyl or methyl methacrylate. Here, the macromonomers exhibited a relatively high molecular weight of 9000, and the reaction was stopped after roughly 20% of the comonomer had been converted. The radical reactivity ratios of styrene and methyl methacrylate with respect to macromonomer were found to be equal to 2 and to 0.5, respectively. From these results, Kennedy concluded that in the ra-styrylpolyisobutene/styrene system the reactivity of the macromonomer double bond is reduced whereas with methacrylate as the comonomer the polar effect is the main driving force, yielding reactivities similar to those observed in the classical system styrene/MMA. 

Coincidental with Ivin and Spensley, O Driscoll and Gasparro (12) studied the free radical copolymerization of styrene-methyl methacrylate but at 250°C. The latter workers varied monomer feed ratio over a wide... 

Figure 10.7. Instantaneous copolymer composition in free-radical copolymerization of styrene and 2-vinyl thiophene mole fraction of styrene in polymer as function of initial mole fraction and fractional conversion of styrene calculated with reactivity ratios pa = 0.35 and pb = 3.10 (from Mayo and Walling [127]).

Another approach for the preparation of organic polymers with cyclophos-phazene side groups involves the Staudinger reaction of an azido- substituted cyclophosphazene with a phosphine residue in an organic copolymer. Free-radical copolymerization of styrene with diphenyl-p-styrylphosphine yields... 

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. 

Figure 22-4. Graphical evaluation of linear copolymerization equations after Fineman-Ross [Equation (22-25)] and Kelen-Tiidos [Equation (22-28)], for the free radical copolymerization of styrene with methyl methacrylate in bulk at 6(f C.

Figure 22-7. Change in mole fraction of monomeric unit, of the reversibly polymerizing a-methyl styrene in the free radical copolymerization with methyl methacrylate at 60 C (above) or with acrylonitrile at 80 C (below) as a function of the overall monomer concentration. In the former case, reversibly depolymerizing disequences (—), and in the latter case, nondepolymerizing disequences (—), were found. (After data from P. Wittmer.)...

Table 22-12. Effect of Solvent on the Copolymerization Parameters in the Free Radical Copolymerization of Styrene with Methyl Methacrylate at 50° C...

Figure 22-12. Arrhenius plot for the temperature dependence of the copolymerization parameters in the free radical copolymerization of styrene (S) with acrylonitrile (AN).

Unsaturated polyesters with molecular weights of several thousand are made commercially by condensing maleic anhydride or phthalic anhydride with ethylene glycol or propylene glycol. The subsequent free radical copolymerization with 30-35% by wt styrene leads to a cross-linked product which possesses exceptionally good mechanical properties, particularly when reinforced with glass fiber. The thermosetting properties... 

FIGURE 10.6 Free-radical concentration versus conversion for the styrene (Sty)/divinylbenzene (DVB) copolymerization initiated with 0.10 M MAIB, at 70°C. [DVB] =0.20 (A), 0.10 ( ), 0.05 ( ), and 0 (A) M. Reprinted from Zetterlund PB, Yamazoe H, Yamada B. Ehopagation and termination kinetics in high conversion free radical copolymerization of styrene/divinylbenzene investigated by electron spin resonance and Fourier-transform near-infrared spectroscopy. Polymer 2002 43 7027-7035. 2002, with permission from Elsevier. 

Vinyl chloride (VC) readily copolymerizes with MA (see table in the appendix to this chapter) maleates and maleimides, using free-radical initiators to give random copolymers.The effect of MA on the chain-transfer constant (C ) during polymerization of vinyl chloride has been studied at 40-70°C. At 60°C, the MA Cs was 7.7 x 10, compared to a styrene Cs of 72.2 X 10. Melville and Burnett determined the copolymerization rate constant for the VC-MA pair to be 2.1 x 10" liter moF s Several studies have shown that equimolar copolymers may also be obtained for the monomer pair (see Chapter 10). It has been observed that the presence of MA enhanced the polymerization rate of vinyl chloride. As shown in the table in this chapter s appendix, vinylidene chloride also undergoes free-radical copolymerization with MA. ... 

Maleic anhydride has also been free-radical copolymerized with a number of other monomer pairs, such as allyl acetate-allyl chloride, vinyl chloride-diethyl fumarate, acrylamide-methacrylic acid, " " trimethylolpropane allyl ethers-methyl acrylate, " and styrene-acetyltriallyl citrate. " Systems of this type are very briefly reviewed. 

A Monsanto patent by Lavengood [38] reported on the free radical copolymerization of styrene (S), acrylonitrile (AN) and maleic anhydride (MA) and the use of these terpolymers in the reactive compatibilization of PA6/ABS blends. Indeed, the amine end groups of nylon react with the MA groups of the terpolymer with formation of a graft copolymer at the interface. 

Ethylene oxide/styrene block copolymers have been further free-radical copolymerized with other ethylenically unsaturated compounds such as methyl methacrylate and methacrylic acid in benzene, tetrahydrofuran, and dimethylformamide (176). Correlations were made between reactivity ratio and solvent dielectric constant, as well as between solubility parameters of reaction solvent and growing polymer chains with marked effects apparent. Gel permeation chromatography of diblock and triblock copolymers based on polystyrene and poly(ethylene oxide) has revealed interesting molecular characteristics (177). Such block copolymers have an amphiphilic character. In aqueous solution, the polymers form spherical micells with a polystyrene core and a poly(ethylene oxide) outer sheath. The investigations used an aqueous-methanolic solution and were able to ascertain block copolymer structures and to estimate the impurities in the diblock copolymer. 

Table 2.13 (Section 2.16.5) gives the reactivity ratios for free-radical copolymerization of styrene with (a) butadiene, (b) methyl methacrylate, (c) methyl acrylate, (d) acrylonitrile, (e) maleic anhydride, (f) vinyl chloride and (g) vinyl acetate. For each of these copolymerizations calculate ... 

By use of an appropriate plot, evaluate the reactivity ratios for free-radical copolymerization of styrene with acrylonitrile. 

Kundu and Larock (2005) copolymerized conjugated (87%) linseed oil, which is more reactive towards free radical reactions, with styrene and divinyl benzene (3-5%) by gradual heating. Soxhlet extractions of the products showed that only 35-85% of the oil could be incorporated into the cross-linked thermosets. The dynamic mechanical analysis of these polymers indicated that they were phase separated, as two separate T s appeared these materials presented a soft rubbery phase with a sharp at -50 C and a hard brittle plastic... 

The backbone chain is made by free radical copolymerization of styrene with some acryloyl chloride. It is reacted in THF solution with silver hexafluoroantimonate. The oxocarbenium salt formed immediately initiates the polymerization of THF (Scheme 23). However, the growth of the grafts has to be stopped at an early stage (by induced deactivation) to prevent formation of bridges between individual chains. The graft copolymers obtained have been characterized accurately. 

In Refs. 125, 126 the viscosity is measured with a magnetic sphere rheometer at decreasing shear rate (its lowest value is 10" s ) in different polymeric systems free-radical copolymerization of styrene-meta-divinylbenzene with solvent and polycondensation of hexamethyl diisocyanate with polyoxypropylene with and without solvent. These experiments yield k = 0.79 in both systems. The standard deviation of experiments performed at different shear rates at the gel points is 0.07 in k. Since t and E are measured in Ref. 126 using the same apparatus and the same sample, T is determined as the time vriiere 9 and E are equal to zero, the precision in Tc being higher than 10" %. 

For the free-radical copolymerization of mono- and bisacrylamide samples performed and with a magnetic sphere rheometer, t = 2.05 0.2 and for the free-radical copolymerization of styrene and divinylbenzene, using the same type of apparatus, t = 2.1 0.3. ITiese exponents are higher than the value of 1.7 predicted by percolation for an alternative theory see however Ref. 107 and smaller than the classical exponent t = 3. 

Styrene-butadiene rubber is prepared from the free-radical copolymerization of one part by weight of styrene and three parts by weight of 1,3-butadiene. The butadiene is incorporated by both 1,4-addition (80%) and 1,2-addition (20%). The configuration around the double bond of the 1,4-adduct is about 80% trans. The product is a random copolymer with these general features ... 

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