Polystyrene homopolymer

Copolymerization allows the synthesis of an almost unlimited number of different products by variations in the nature and relative amounts of the two monomer units in the copolymer product. A prime example of the versatility of the copolymerization process is the case of polystyrene. More than 11 billion pounds per year of polystyrene products are produced annually in the United States. Only about one-third of the total is styrene homopolymer. Polystyrene is a brittle plastic with low impact strength and low solvent resistance (Sec. 3-14b). Copolymerization as well as blending greatly increase the usefulness of polystyrene. Styrene copolymers and blends of copolymers are useful not only as plastics but also as elastomers. Thus copolymerization of styrene with acrylonitrile leads to increased impact and solvent resistance, while copolymerization with 1,3-butadiene leads to elastomeric properties. Combinations of styrene, acrylonitrile, and 1,3-butadiene improve all three properties simultaneously. This and other technological applications of copolymerization are discussed further in Sec. 6-8. 

The particle size information for the latexes selected for structural characterization is shown in Table XIV. The homopolymer polystyrene seed latex was used to prepare the two-stage... 

The largest use for styrene (over 70%) is to make homopolymer polystyrene. The U.S. production volume reached 6.3 billion lb in 1998. Other major uses are in plastics, latex, paints, and coatings, synthetic rubbers, polyesters, and styrene-alkyd coatings. In these applications styrene is used in copolymers... 

Figure 4.27 Traiumission electron micrographs of a mixture of a star diblock copolymer (polybutadiene-polystyrene) with a homopolymer (polystyrene). The upper EM images show mesh layers viewed end-on. The lower image shows the mesh sheets viewed from above, revealing the dense network of pores in the layers, so that the sheets are in fact a filigree of interconnected tunnels. The large-scale dark (one marked A) and bright (B) fringes are due to variations in the thickness of the specimen only. Pictures reproduced witti permission from [48].

Blends. The type I reaction produces free radicals which, in the presence of oxygen, initiates photooxidation which also results in a decrease in the polymer molecular wei t. An indication of the relative importance of the type I reaction in these systems can be estimated from the amount of chain scission induced in a blend of the copolymers with homopolymer polystyrene. For these experiments, one part of 5% vinyl ketone copolymer was blended with four parts of styrene homopolymer to retain an overall ketone monomer concentration of 1%. 

A mixture of graft copolymer, parent polymer (polyethylene), and homopolymer (polystyrene) results from the operation. 

Synonyms Atactic polystyrene Benzene, ethenyl-, homopolymer Ethenylbenzene homopolymer Polystyrene latex Polystyrene resin Polystyrol PS Styrene polymer Styrene, polymerized Vinylbenzene polymer... 

Figure 7.78 represents the heat capacities of the homopolymers polystyrene and poly(a-methyl styrene) with sharp glass transitions at 375 and 443 K, respectively [35]. On copolymerization to a triblock molecule, MS-S-MS(45), a much broader glass transition results. It stretches from the polystyrene to the poly(a-methylstyrene) glass transition and could indicate a solution, but the molar mass seems too high for solubility when compared to Fig. 7.75 in Sect. 7.3.2 (M, = 10 Da). Similarly, the figure indicates broad transition regions for the other copolymers. 

Poly(dimethylsiloxane) (PDMS) is a well-known hydrophobic polymer with higher repellency for water than PS crosslinked siUcone elastomers (WCA = 112° for a smooth film) are commonly used for fabricating microfluidic devices. But forming solid fibers comprised solely of linear PDMS is not possible, due to its low glass transition temperature. Instead of using linear homopolymer PDMS, Ma et al. [21] electrospun fibers of poly(styrene-b-dimethylsiloxane) block copolymers blended with 23.4 wt% homopolymer polystyrene (PS-PDMS/PS) from a solution in a mixed solvent of THF and DMF. The resultant fiber mat, with fiber diameters in the range of 150-400 nm, exhibited a WCA of 163° and a hysteresis of 15°. An illustration of water droplets beaded up on such a mat is provided in Fig. 3. A PS mat of similar fiber diameter and porosity exhibited a WCA of only 138°. The difference was attributed to the lower surface tension of the PDMS component, combined with its spontaneous segregation to the fiber surface. X-ray photoelec-... 

We have studied two vinyl-peptide block copolymers a copolymer polystyrene-poly(Y benzyl-L-glutamate) (SG) and a copolymer poly-styrene-poly (L-glutamic acid) (SE) and the corresponding hydrophobic homopolymers polystyrene (S) and polyCy-benzyl-L-glutamate) (G). The molecular weight of the polystyrene blocks was 25,000 and the polypeptide content of the copolymers was about 50 %. 

Figure 6 The apparent heat capacity at 20K/min. of homopolymer polystyrene blends, measured 5 days after compaction.

In this chapter the homopolymer, polystyrene, is considered together with styrene-acrylonitrile copolymers, acrylonitrile-butadiene-styrene copolymers and styrene-a-methylstyrene copolymers. The important styrene-butadiene copolymers are described with other diene polymers in Chapter 18. The use of styrene in the cross-linking of unsaturated polyesters is described in Chapter 10. 

Fig. 15. Pulsed ELDOR (DEER) distance measurements on the ionic spin-probe TEMPO-4-carboxylate attached to ionic clusters in ionically modified diblock copolymers, (a) Schematic structure of a monoionic polystyiene-polyisoprene diblock copolymer modified by sulfonate end groups on the polyisoprene bloek (sample series S). (b) Schematic structure of an a,0)-zwitterionic polystyrene- ly-isoprene diblock copolymer modified by a quaternary ammonium end group on the polystyrene block and a sulfonate end group on the polyisoprene block (sample series Z). (c) Schematic structures of the polymer chains. Tlie solid line corresponds to the harder block polystyrene, the dotted line to the softer block polyisoprene. (d) Dependence of ionic cluster size (ri) and intercluster distance (r2> on molecular weight. Squares correspond to sample series Z, circles to sample series S, and diamonds to monionic homopolymers (polystyrene modified with quaternary ammonium end groups). The dotted and dashed lines are fits of a constant function. The solid line is the best-fit scaling law r2 = 2.09...

Typical stress-relaxation moduli are given in Fig. 9 as a function of log time, for several SINs and a homopolymer PSN. In each case, the data were correlated through the use of the time-temperature superposition principle in the form of a master curve, with a reference temperature of 100 C. This reference temperature is near the glass transition temperature of homopolymer polystyrene. 

TLC has been used in the study of many homopolymers polystyrene, poly(methyl methacrylate), poly(ethylene oxide), polyisoprene, poly(vinyl acetate), poly(vinyl chloride) and polybutadiene. Their molecular weight, molecular-weight distributions, microstructure (stereo-regularity, isomerism and the content of polar end groups), isotope composition and branching have been studied. For copolymer characterisation (e.g. purity and compositional inhomogeneity), random copolymers such as styrene-methacrylate, and block copolymers such as styrene-butadiene, styrene-methyl methacrylate and styrene-ethylene oxide have been separated. A good review article on polymers... 

Rutledge et al. showed that fiber mats composed solely of uniform fibers could be obtained by electrospinning a hydrophobic material (i.e., poly(styrene-block-dimethylsiloxane) block copolymer) blended with homopolymer polystyrene (PS) [24]. The roughness of the nonwoven mat, resulting from the small diameters of the fibers (150-400 nm), combined with the enrichment of the dimethylsiloxane... 

Polypropylene Polypropylene, Copolymer Polypropylene, Homopolymer Polystyrene (PS)... 

Polyethylene Terephthalate (PET) Polyethylene, HDPE Polymethyl Methacrylate (PMMA) Polypropylene Polypropylene, Copolymer Polypropylene, Homopolymer Polystyrene (PS)... 

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