Styrene butylmethacrylate

Loutfy et al. (1983) measured the photoconductivity of a series of squaraines dispersed in a styrene butylmethacrylate copolymer. The generation efficiencies were strongly field dependent. In most materials, a quadratic field dependence was observed. For MSQ, the results were in agreement with Tam. At high fields, the efficiency was approximately 0.70. 

The reactivity ratios were determined by performing a thermal polymerization at 135°C of several styrene-butylmethacrylate mixtures in which the mole fraction of styrene varied from 0.1 to 0.9 (3). Except for the mixture with a styrene mole fraction of 0.1, all mixtures showed thermal polymerization. When these mixtures had reached a conversion of 5 to 10%, the polymerization was stopped by cooling the mixture rapidly. The polymer monomer mixture was precipitated in methanol and dried in a vacuum oven. The different copolymers were analyzed by elemental analysis. The determination of the carbon and oxygen content in the copolymer gave the amount of styrene in the copolymer. The results are shown in Figure 8.4. By using the method of Kelen-Tudos (4-6), the reactivity ratios were determined at ri = 0.40 0.03 and r2 = 0.86 0.03 (styrene is monomer A). 

Poly(styrene-fr-2-vinylpy r idin e-b-tert-butylmethacrylate)... 

Frechet and coworkers recently described how living free radical polymerization can be used to make dendrigrafts. Either 2,2,6,6-tetramethylpiperidine oxide (TEMPO) modified polymerization or atom transfer radical polymerization (ATRP) can be used [96] (see Scheme 10). The method requires two alternating steps. In each polymerization step a copolymer is formed that contains some benzyl chloride functionality introduced by copolymerization with a small amount of p-(4-chloromethylbenzyloxymethyl) styrene. This unit is transformed into a TEMPO derivative. The TEMPO derivative initiates the polymerization of the next generation monomer or comonomer mixture. Alternatively, the chloromethyl groups on the polymer initiate an ATRP polymerization in the presence of CulCl or CuICl-4,4T dipyridyl complex. This was shown to be the case for styrene and n-butylmethacrylate. SEC shows clearly the increase in molecu-... 

Neutralizing these polyesters with different hydroxyamines made it possible to obtain stable micellar systems. The size of these micelles was shown to essentially be a function of the structure and the polyester molecular weight. The smallest micelles are obtained with diacid polyester of lower molecular weight. A model for the chain conformation of polyester in a micelle was proposed, taking into account the area occupied by one end group located at the micelle surface. Furthermore, such micelles were demonstrated to be able to solubilize non-neutralized polyester chains, as well as monomers like styrene or butylmethacrylate (BMA). 

Moad also notes that the most common grafting modifications made to polyolefins are via maleic anhydride, maleate esters, styrene, maleimides, acrylates and their esters, and vinyl silanes. Other polymer systems (Fink, 2005) that undergo grafting are polystyrene/maleic anhydride (useful for PA6/PS blends), PVC/butylmethacrylate (for improved processi-bility), PET/nadic anhydride, starch/vinyl acetate and starch/methyl acrylate (for improved water resistance). 

Other polymers which degrade in organic solutions include poly-n-butylmethacrylate [450] and copolymers of styrene and a-methylstyrene [451],... 

Abbreviations for the polymeric units in Table 2.10 (C H )- - phenyl ring, a-MS - alpha-methyl styrene, AN, acrylonitrile, BMA - butylmethacrylate, CHMA - cyclohexylmethacrylate. Cl - caprolactone, C(VC) - unit of chlorinated PVC, DNS - 2,4-dini-trostyrene-co-styrene, DTC -2,2-dimethyltrimethylenecarbonate, HFPC - hexafluoro bisphenol-A polycarbonate, MA - maleic anhydride, MMA - methylmethacrylate, PAr - unit of polyarylate, Phenoxy - unit of polyhydroxy ether of bisphenol-A, PPE - unit of poly(2,6-dimethyl-1,4-phenylene ether), S - styrene, TMPAr - unit of tetramethyl bisphenol-A polyarylate, TMPC - unit of tetramethyl bisphenol-A polycarbonate, VAc - vinyl acetate, VC - vinyl chloride, VCVAc90 - VC-co-VAc copolymer with 90 wt% VC, VME - vinylmethylether. 

Rotational relaxation times of polymers in solution are generally such that probes with nanosecond fluorescence decay times suffice for measurement of p. For faster relaxation, picosecond time resolution is required, and this may have applications in the polymer field. One should therefore pay tribute to the extraordinarily elegant instrumentation that is now available for picosecond rotational relaxation measurements on smaller molecules (85-87). Much more viscous solutions can be studied if long-lived phosphorescence is used as the luminescence monitor, and such studies on a millisecond time scale have recently been carried out on poly(vinyl alcohol), poly(ethylmethacrylate), poly-(styrene), poly(butylmethacrylate), and poly(methylmethacrylate) using benzophenone and anthrone as probes (88). 

Zimmerman and co-workers reported a similar quadmple complementary H-bonding pair (designed to minimize homodimerization of one of the units) with very high Ka values (3 X 10 M" ) used to prepare a styrenic and methacrylate monomer subsequently copolymerized with styrene and n-butylmethacrylate, respectively, via traditional free-radical polymerization. Blends of the polymers clearly formed networks in the bulk and in chloroform solutions. 

Several other examples have been reported in the literature in which one single BCP has been used. On the contrary, studies using blends are rather scarce. Krausch and coworkers [57] adsorbed a linear ABC triblock copolymer of poly(styrene-b-2-vinylpyridine-b-tert-butylmethacrylate) onto the SiO surface of a silicon wafer to fabricate a nanostructured support and analyze the microphase separation of a polymer blend on this substrate. The BCP used exhibits a lateral microphase separation as a consequence of the strong affinity of the middle block [ie, poly(vinylpyrrolidone) (PVP)] to the boundary surface. Interestingly, the phase separation of the homopolymers... 

If the results for butylmethacrylate are compared with reactive extrusion of styrene the maximum conversion is much lower in the case of butylmethacrylate. Styrene could be polymerized up to a conversion of almost 99%, while in the case of butylmethacrylate the highest conversion was 96.3%. This limitation indicates the importance of the ceiling temperature as described by Dainton (14). It is known in literature (15) that methacrylates possess a relatively low ceiling temperature, which means that the influence of thermodynamic limitations is most pronounced for these components. Bywater (16) found for methylmethacrylate an equilibrium monomer concentration of 0.3mol/l at 132°C, which was independent of the amount of polymer formed after reaction. This imphes... 

The product of this polymerization is applied in specialty areas, such as the manufacture of recording tapes and toners for photocopiers. When styrene (St) and butylmethacrylate (BMA) are mixed in the molar ratio 1 1, the polymer formed is transparent and has a glass transition temperature of about 30°C. Figure 8.3 shows the two monomers. The conversion in this case is measured gravimetrically. The product was dissolved in THF, and a small amount of hydroquinone was added to inhibit further reaetion. The molecular weight distribution was determined by gel permeation ehromato-graphy (GPC) with two mixed columns of polymer laboratories. The detection method used was by reactive index. 

Figure 8.8 Typical molecular weight distribution for the copol5merization of styrene and butylmethacrylate.

Figure 13.9 DSC experiments at different temperatures for a butylmethacrylate-styrene mixture.

The chemical modification of homopolymers such as polyvinylchloride, polyethylene, poly(chloroalkylene sulfides), polysulfones,poly-chloromethylstyrene, polyisobutylene, polysodium acrylate, polyvinyl alcohol, polyvinyl chloroformate, sulfonated polystyrene block and graft copolymers such as poly(styrene-block-ethylene-co-butylene-block-styrene), poly(1,4-polybutadiene-block ethylene oxide), star chlorine-telechelic polyisobutylene, poly(lsobutylene-co-2,3-dimethy1-1,3-butadiene), poly(styrene-co-N-butylmethacrylate) cellulose, dex-tran and inulin, is described. 

Poly(styrene- -2-vinylpy r idine- tert-butylmethacrylate) 1... 

---