Styrene/ethyl methacrylate copolymer

The chlorinated alkanes have proven useful for solubilizing lower molecular weight polymers and oligomers. As detailed in the alkane and alcohol chapters, dichloro-methane (DCM) has been used in conjunction with methanol and heptane gradients for the characterization of polystyrenes [272] and styrene/ethyl methacrylate copolymers [649] and with heptane for co-poly (styrene/acrylonitrile) materials [244, 527]. 

More quantitative studies have shown that, although some hypochromism effects exist, they are small. For example, Monnerie I9) examined the integrated molar extinction coefficient of atactic PS in chloroform and found only a 2 % decrease for the polymer relative to ethyl benzene. In addition, Vala and Rice 15 reported a 10% decrease in absorption for the 260 nm band of isotactic PS relative to atactic PS, which was qualitatively confirmed by Longworth18>. Similarly, Cantow 8> observed a 4% hypochromism of the 261.5 nm band of isotactic PS in dioxane relative to atactic PS. Finally, Cantow 8) observed strong hypochromism (relative to atactic PS) ranging from 19% at 262 nm to 32% at 269 nm for an alternating styrene-methyl methacrylate copolymer and for random copolymers having a low styrene content. 

Figure 3. Effect of polymer concentration on the viscosity changes on reaction between styrene-hydroxy ethyl methacrylate copolymer (2.2 mole % HEMA) and hexamethylene diisocyanate in toluene at 80° C. [2VCO]0 [OH 0 = 1. Polymer concentrations 0.047% (gram/dl.) (%), 0.134% (gram/dl.)...

Preparation and Characterization of Styrene—Hydroxy ethyl Methacrylate Copolymers... 

To study the internal crosslinking of styrene-hydroxy ethyl methacrylate copolymers, it was necessary to prepare a range of well characterized materials containing only low concentrations of hydroxyethyl methacrylate. To ensure that the copolymers were of uniform composition, only low monomer conversions were used so that the composition of the monomer mixtures did not change appreciably during the reaction. Low polymerization temperatures were used to obtain high molecular weight copolymers. 

Styrene copolymers of methyl, ethyl, and n-butyl acrylates and methacrylates were also separated according to their compositions (8) (Figure 3). Part of poly (styrene-ethyl methacrylate) P(S-EMA) copol-... 

Plots of the relationship between the styrene content and retention volume for copolymers of styrene-acrylate and styrene-methacrylate with the same ester group lay roughly on the same line. This result indicates that a pair of copolymers with the same ester group and the same styrene content could not be separated (24), For example, copolymers of styrene-methyl acrylate and styrene-MMA with the same styrene content cannot be separated by this technique. In copolymers with the same styrene content, styrene-butyl acrylate and styrene-butyl methacrylate copolymers eluted first from a column, the copolymers of ethyl esters were next, and those of methyl esters eluted last. 

It has been reported that in ethyl acetate and dichloroethane solution, the position of the excimer band is concentration dependent The interpretation of solvent effects is complex. Since the compactness of the pdymer coil will affect the efficiency of energy migration and the ccmcentration of aromatic species in conformations suitable for excimer formation, sdvent effects are to be expected in polymers in which excimer formation is the result of nearest-neighbour interactions, as is the case in styrene as shown in studies on styrene-methyl methacrylate copolymers ... 

In a study of the flame retardance of styrene-methyl methacrylate copolymer with covalently bound pyrocatechol-vinyl phosphate, diethyl p-vinyl benzyl phosphonate, or di(2-phenyl ethyl phosphonate) groups. Ebdon and co-workers [23] obtained data on their decomposition behaviour. This was achieved by reducing the rate of liberation of flammable methyl methacrylate monomer during combustion. Possible mechanisms for these processes are suggested. Other methacrylate copolymers which have been the subject of thermal degradation studies include PMMA-N-methylmaleimide-styrene [24] and PMMA-ethylene vinyl acetate [25-27]. 

A combination of liquid adsorption chromatography (LAC)-SEC, or SEC-LAC, has recently been developed by several workers. Danielewicz and Kubin [66] separated random copolymers of P(S-MMA) and styrene-ethyl methacrylate according to chemical composition on a silica gel column, with a mixture of 1, 2-dichloroethane (DCE) and THE as the mobile phase. Separation was almost independent of the sample molecular mass. 

A 30-min 99/1->93/7 chloroform/ethanol gradient was used with a silica column (A = 254nm) to characterize styrene/methyl and ethyl methacrylate copolymers [755]. That the ethanol content was critical was shown through a series of chromatograms for a 50/50 styrene/methyl methacrylate co-polymer and a 35/65 styrene/ethyl methacrylate co-polymer. For 25 pL injections of 0.1% w/v samples, the 50/50 co-polymer completely eluted with a 97/3 chloroform/ethanol mobile phase but was completely adsorbed to the silica at 99/1. Similarly, the 35/65 copolymer eluted at 95/5 chloroform/ethanol and did not elute at 98/2. Temperature effects (40-70°C) on the level of ethanol needed for elution were tabulated for these co-polymers as well. 

The foUowing activity coefficients and interaction parameters determined by GLC for solute-statistical copolymers may be found in the literature (a) forty three non-polar and polar solutes on ethylene-vinyl acetate copolymer with 29% weight of vinyl acetate at 150.6 and 160.5°C [105] chloroform, carbon tetrachloride, butyl alcohol, butyl chloride, cyclohexanol, cyclohexane, phenol, chlorobenzene and pentanone-2 on the same copolymer with 18% weight vinyl acetate at 135°0 [102], normal xdkanes (C5, Oj, Og, Ojo), oct-l-ene, chlorinated derivatives, n-butanol, toluene, benzene, methyl-propyl-ketone and n-butyl-cyclohexane on the copolymer mentioned with 40% weight vinyl acetate at 65, 75 and 85°0 [68, 106] (b) n-nonane, benzene, chloroform, methyl-ethyl-ketone and ethanol in methyl methacrylate-butyl methacrylate copolymer with 10% butyl methacrylate [32] (c) hydrocarbons in styrene-alkyl methacrylates copolymers at 140°C [101] (d) the solutes in (b) on butadiene-acrylonitrile copolymer with 34% weight acrylonitrile [68]. 

A number of studies have uncovered instances of miscibility in mixtures of homopolymer A with copolymer CD when the corresponding homopolymer pairs A/C, A/D, and C/D are immiscible. The copolymer of styrene and acrylonitrile has been found to be miscible with a fairly large number of polymers, including poly(vinyl chloride) poly(e-caprolactone) sulfone based polymers poly(methyl methacrylate) and poIy(ethyl methacrylate) Copolymers of a-methylstyrene... 

For example, this method was carried out for various copolymers, namely styrene-methyl methacrylate copolymer [65-67], epoxide resins [68], styrene-acrylic acid copolymer [69], styrene-2-methoxyethyl methacrylate copolymer [70, 71], ethylene-ot-olefin copolymer [72], partially modified dextran-ethyl carbonate copolymer [73], vinyl chloride-vinyl acetate copolymer [43], styrene-acrylonitrile copolymer [74], and styrene-butadiene copolymer [75]. 

Mori, S., Separation and detection of styrene-alkyl methacrylate and ethyl methacrylate-butyl methacrylate copolymers by liquid adsorption chromatography using a dichloroethane mobile phase and a UV detector, J. Chromatogr., 541, 375, 1991. 

Accordingly, the synthesis of novel cinnamate polymers with high functionality and performance is very important from the viewpoint of both polymer chemistry and practical use. Recently, we have reported the synthesis of polymers with pendant photosensitive moieties such as cinnamic ester and suitable photosensitizer groups by radical copolymerizations of 2-(cinnamoyloxy) ethyl methacrylate with photosensitizer monomers (9), by copolymerizations of chloromethylated styrene with the photosensitizer monomers followed by the reactions of the copolymers with salts of... 

Graft copolymers of polyamides using pre-irradiation gamma-rays techniques have been reported for styrene (130), in solution, in the presence of water (40), in alcohols or acetone solution (131), vinyl acetate (130), methacrylic acid in water (132) or methanol solution (129), methyl (133) and ethyl (130) acrylates, 2-ethylhexyl acrylate (55,134), methyl methacrylate (130), in methanol solution (129), 2-dimethylamino ethyl methacrylate quaternary salts (135), acrylamide in aqueous medium (128,136), acrylonitrile (130,137), and 4-vinyl pyridine in aqueous solution (128). 

Macroradicals obtained by the copolymerization of equimolar quantities of styrene and maleic anhydride in benzene or in cumene were also used as initiators to produce block copolymers with methyl methacrylate, ethyl methacrylate, and methyl acrylate. The yields of these block copolymers were less than those obtained with styrene, but as much as 38% of methyl methacrylate present in the benzene solution added to the macroradical to produce a block copolymer. The amount of ethyl methacrylate and methyl acrylate that was abstracted from the solution to form block copolymers was 35 and 20%. 

The freeze/thaw (F/T) stability of a polymer emulsion serves as a macroscopic probe for investigating the properties of the average particle in a polymer emulsion. A review of the factors which contribute to this stability is included. A study of styrene-ethyl acrylate-methacrylic acid polymers shows the existence of a minimum in the plot of minimum weight percent acid required for F/T stability vs. the minimum film formation temperature (MFT) of the polymer. This is considered to be a function of both the amount of associated surfactant and the minimum acid content. Thus, both the type of surfactant and the copolymer ratio—i.e., MFT—play major roles. Chain transfer between radicals and polyether surfactant resulting in covalently bonded surfactant-polymer combinations is important in interpreting the results. 

To this end, work has been initiated on a series of somewhat less polar styrene-ethyl acrylate-methacrylic acid emulsion polymers. The first major difference encountered in changing from the MMA-EA-MAA to the S-EA-MAA polymers was the need for at least a 50% increase in surfactant to obtain a coagulate-free emulsion for the 100% styrene vs. 100% methyl methacrylate. The determination of the minimum weight percent of MAA required to yield a F/T stable emulsion for various copolymers gave the results listed in Table III. 

More or less similar behavior has been observed (8) in the blends of the copolymer or the terpolymer with the following bis-A polycarbonate, polyvinyl chloride, poly (ethyl methacrylate), and a terpolymer made from methyl methacrylate, N,N -dimethyl acrylamide, and N-phenyl-maleimide. Because of this unique miscibility characteristic of the a-methyl styrene interpolymers, an attempt was made at compati-bilizing polyarylethers with the interpolymers by attaching pendant chemical groups known to exist in systems with which the interpolymers are miscible. 

A final example of the application of 13C NMR spectroscopy is taken from our work9 on copolymers of methacrylates and vinyl phenol which were synthesized using similar chemistry to that shown previously for the styrene-co-vinyl phenol copolymers. In Figure 7-48 are typical 13C NMR spectra of an ethyl methacrylate (EMA) copolymer containing 52 mole % EMA before (top) and after (bottom) deprotection. The absence of the NMR peaks at around 0 ppm (the two methyl carbons attached to silicon), 19 ppm (the tertiary carbon of the f-butyl group), and 26 ppm (the three methyl carbons on the f-butyl group) after desilylation, clearly indicates the absence of any residual f-butyldi-methylsilyl groups. 

Most research into the study of dispersion polymerization involves common vinyl monomers such as styrene, (meth)acrylates, and their copolymers with stabilizers like polyvinylpyrrolidone (PVP) [33-40], poly(acrylic acid) (PAA) [18,41],poly(methacrylicacid) [42],or hydroxypropylcellulose (HPC) [43,44] in polar media (usually alcohols). However, dispersion polymerization is also used widely to prepare functional microspheres in different media [45, 46]. Some recent examples of these preparations include the (co-)polymerization of 2-hydroxyethyl methacrylate (HEMA) [47,48],4-vinylpyridine (4VP) [49], glycidyl methacrylate (GMA) [50-53], acrylamide (AAm) [54, 55], chloro-methylstyrene (CMS) [56, 57], vinylpyrrolidone (VPy) [58], Boc-p-amino-styrene (Boc-AMST) [59],andAT-vinylcarbazole (NVC) [60] (Table 1). Dispersion polymerization is usually carried out in organic liquids such as alcohols and cyclohexane, or mixed solvent-nonsolvents such as 2-butanol-toluene, alcohol-toluene, DMF-toluene, DMF-methanol, and ethanol-DMSO. In addition to conventional PVP, PAA, and PHC as dispersant, poly(vinyl methyl ether) (PVME) [54], partially hydrolyzed poly(vinyl alcohol) (hydrolysis=35%) [61], and poly(2-(dimethylamino)ethyl methacrylate-fo-butyl methacrylate)... 

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