Copolymer of styrene and methyl

Figure 9.17 Plot of log [i ]M versus retention volume for various polymers, showing how different systems are represented by a single calibration curve when data are represented in this manner. The polymers used include linear and branched polystyrene, poly(methyl methacrylate), poly(vinyl chloride), poly(phenyl siloxane), polybutadiene, and branched, block, and graft copolymers of styrene and methyl methacrylate. [From Z. Grubisec, P. Rempp, and H. Benoit, Polym. Lett. 5 753 (1967), used with permission of Wiley.]...

The same procedure can be employed to make well defined comb-like polymers Living polystyrene can be grafted onto a partially chloromethylated polystyrene89 146), or onto a random copolymer of styrene and methyl methacrylate containing less than 10% of the latter monomer I48). 

The adsorption of block and random copolymers of styrene and methyl methacrylate on to silica from their solutions in carbon tetrachloride/n-heptane, and the resulting dispersion stability, has been investigated. Theta-conditions for the homopolymers and analogous critical non-solvent volume fractions for random copolymers were determined by cloud-point titration. The adsorption of block copolymers varied steadily with the non-solvent content, whilst that of the random copolymers became progressively more dependent on solvent quality only as theta-conditions and phase separation were approached. 

Figure 1. Random copolymers of styrene and methyl methacrylate. (v ). of CC1,/C H1A mixtures as function of...

Hadziioannou et al. [296] employed an analog surface-bond initiator for RAFT-SIP on silica substrates to prepare homogeneous block copolymers of styrene and methyl methacrylate. A patterned substrate was prepared by selective deposition of the initiator. 

Example An unspecified copolymer of styrene and methyl methacrylate is named poly[styrene-co-(methyl methacrylate)]. 

Copolymers are composed of two or more monomers. Source-based names are conveniently employed to describe copolymers using an appropriate term between the names of the monomers. Any of half a dozen or so connecting terms may be used depending on what is known about the structure of the copolymer. When no information is known or intended to be conveyed, the connective term co is employed in the general format poly(A-co-B), where A and B are the names of the two monomers. An unspecified copolymer of styrene and methyl methacrylate would be called poly[styrene-co-(methyl methacrylate)]. 

Fig. 1. Styrene-content dependence of jR-f observed for statistical copolymers of styrene and methyl acrylate (reproduced from Ref.16) by permission of the American Chemical Society)...

Kress, A.O., Mathias, L.J. and Cei, G., Copolymers of styrene and methyl a-(hydroxymethyl)acrylate reactivity ratios, physical behavior, and spectral properties, Macromolecules, 1989, 22, 537. 

Jones, M. H. Graft copolymers of styrene and methyl methacrylate. I. Synthesis. Canad. J. Chem. 34, 948 (1956). 

Reaction (9-23) could be used to produce an ABA copolymer of styrene and methyl methacrylate even though the latter anion is too weakly basic to initiate the polymerization of styrene. If the presence ofa linking group, like the—(—CH2—) in the above reaction, is undesirable a coupling agent like I2 can be used. 

In addition to these irregularities, Winey et al. (1996) have found that in random and alternating copolymers of styrene and methyl methacrylate, the sequence distribution of monomers along the backbone of the polymer strongly affects its miscibility with polystyrene and polymethylmethacrylate homopolymers, even when the overall ratio of styrene/methyl methacrylate in the copolymer chain is held constant. A strictly alternating sequence of monomers in the copolymer was found to be more miscible with the ho-miopolymers than is a copolymer with a random sequence distribution. These results... 

Block copolymer of styrene and methyl methacrylate. The polyazoester is made by the reaction of a diol and AIBN. The procedure is described elsewhere (16). 

The order of monomer addition is important. For example, to prepare an AB type block copolymer of styrene and methyl methacrylate, st ene must be polymerized first using a monofunctional initiator and when styrene is completely reacted, the other monomer MMA must be added. The copolymer would not form if MMA were polymerized first, because living poly(methyl methacrylate) is not basic enough to add to styrene. The length of each block is determined by the amount of corresponding monomer which was provided. To produce ABA type copolymer by monofunctional initiation, B can be added when A is consumed, and A added again when B is consumed. This procedure is possible if the anion of each monomer sequence can initiate polymerization of the other monomer. Multiblock copolymers can also be made in this way. 

The most common technique for improving the properties of a polymerized monomer is to allow it to copolymerize with another monomer. We distinguish between random, graft, block, and alternating copolymers as well as network structures in Figure 1. These copolymers differ in their performance characteristics. The effect of their structure on properties is discussed by S. Russo and B. M. Gallo using copolymers of styrene and methyl methacrylate as examples. 

Solvent effects on the optical densities of alternating and random copolymers of styrene and methyl methacrylate can explain the variation in hypochromism at 269.5 nm (see Figure 1 and Table II). Actually, the hypochromism seems to depend on specific interactions between methyl methacrylate mers and styrene mers. Good correlations between hypochromism and chemical structure of the copolymers can be deduced on the basis of the sequence length distribution. 

URW Urwin, J.R. and Steame, J.M., Solution properties of block copolymers of styrene and methyl methacrylate. Part. II. Viscosity, osmotic pressure, and hght scattering... 

KOT Kotaka, T., Ohnutna, H., and Murakami, S., The theta-condition for random and block copolymers of styrene and methyl methacrylate, Y, J. Phys. Chem., 70, 4099, 1966. 

The first set of experiments that will be considered has examined the ability of random copolymers of styrene and methyl methacrylate to improve the interfacial strength between polystyrene and poly(methyl methacrylate). Using the asymmetric double cantilever beam technique, the researchers have found that a diblock copolymer (50/50 composition, Mw = 282,000) creates an interface with strength of400 J/m2. When utilizing a random copolymer however, it was found that the strongest interface (70% styrene, Mw =... 

Utracki, L. A., Simha, R., Interactions in solutions of block and statistical copolymers of styrene and methyl methacrylate. Macromolecules, 1(6), pp. 505-509 (1968). 

Copolymers of styrene and methyl methacrylate were separated by composition in numerous eluents. Most of them represented proper normal-phase systems with gradients increasing in polarity and a polar stationary phase. Figure 12 shows the separation of the mixture of seven statistical poly(styrene-co-methyl methacrylate)s on a silica column through a gradient i-octane/ (THF + 10% methanol) [35]. 

After these initial considerations, the complete analysis of a number of diblock copolymers of styrene and methyl methacrylate shall be discussed in detail. The poly(styrene-ftlodc-methyl methacrylate)s under investigation were prepared via anionic polymerization of styrene and subsequent polymerization of methyl methacrylate, varying molar mass and composition (B1-B3). The polystyrene precursors (P1-P3) were isolated and characterized separately. As the PMMA block is the more polar block in the block copolymer, a polar (silica gel) column was chosen for establishing the critical point of PMMA. According to case (1) in Fig. 14, the PS block is then eluted in the SEC mode. The behavior of PMMA of different molar masses on silica gel Si-100 in eluents comprising methylethylketone and cyclohexane is shown in Fig. 15A [37]. 

P(HB-b-I-S) Block copolymer of hydrogenated butadiene, isoprene, and styrene P(S-b-MMA) Block copolymer of styrene and methyl methacrylate PA Polyamide... 

Homonuclear correlation via the nuclear Overhauser effect (NOESY). The NOESY experiment correlates peaks by means of the nuclear Overhauser enhancement and so identifies pairs of nuclei which are sufficiently close together in space to relax by their dipole-dipole interaction. This technique is not so applicable in determining stereochemical assignments as those described previously, but may be extremely useful in determining the chain conformation as demonstrated by Mirau et al. in a study of the alternating copolymer of styrene and methyl methacrylate [45] (see chapter 4). 

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