Influence of Styrene

Figure 11.18 Influence of styrene content on properties of ethylene-styrene copolymers (based on...

Particular mention should be made of the influence of styrene monomer (Figure 16.10). An increase of the residual monomer from 0 to 5% can cause a 30°C reduction in softening point. On the other hand there is a marked increase in the ease of flow. It is not, however, good practice to change the flow properties in this way as the monomer will volatilise in the processing machine and the... 

Figure 16.10. Influence of styrene monomer content of the softening point and flow characteristics of polystyrene, (After Haward and Crabtee) ...

By means of an apparent Michaelis constant (A mapp) together with a maximum rate ( max) of butadiene metabolism both obtained with human liver microsomes (Filser et al., 1992), Filser et al. (1993) constructed a human model which was later extended by Csanady et al. (1996) for the butadiene metabolites epoxybutene and diepoxybutane. For butadiene and epoxybutane, the required human tissue air partition coefficients were measured using autopsy material (Table 23). Filser et al. (1993) investigated the influence of styrene co-exposure on butadiene metabolism by assuming competitive interaction. Simulations for a 70-kg man exposed over 8 h to 5 or 15 ppm [11 or 33 mg/m3] butadiene indicated total amounts of butadiene metabolized of 0.095 and 0.285 mmol, respectively, reduced by about 19% and 37% as a result of co-exposure to 20 and 50 ppm styrene, respectively. No influence of butadiene on styrene metabolism was noted. 

Schellenberg J and Hamann B (1993) Influence of styrene-acrylonitrile oligomers on the properties of ABS graft copolymers. Eur Polym J 29 727-30. 

Journal of Applied Polymer Science 71, No. 10,7th March 1999, p. 1581-95 INFLUENCE OF STYRENE CONTENT ON THE HYDROGENATION OF STYRENE-BUTADIENE COPOLYMER... 

Soon after vinyl BR s were first introduced commercially, it was recognized that the vinyl structure imparted non-typical dynamic properties. In particular, their vulcanizates showed improved resistance to heat build-up when compared to emulsion SBR. j O Before relating the special contribution of the vinyl structure to properties, it is informative to first determine the influence of styrene content (at constant vinyl) on the two fundamental properties of interest Tg and tan 6, as shown in Figure 14. As expected, both Tg and tan 6 increase almost linearly with styrene content. Thus like a conventional tire tread rubber, the rolling resistance of solution SBR s prepared using lower amounts of styrene is accompanied by a decrease in the wet traction of the rubber. 

Influence of Styrene and Vinyl Contents on Wet Traction and Rolling Resistance... 

J.Y. Li, K. Sato, S. Ichizuri, S. Asano, S. Ikeda, M. lida, A. Oshima, Y. Tabata and M. Washio, Pre-irradiation induced grafting of styrene into cross-linked and non-cross-linked polytetrafluoroethylene films for polymer electrolyte fuel ceU applications. I Influence of styrene grafting conditions, Eur. Polym. J. 40, 775 (2004). 

The influence of styrene concentration in UPR on the miscibility with unsaturated polyester and the mechanical properties was investigated [24]. A commercial UPR containing 38 wt % styrene was used to prepare samples with 6-58 wt % styrene by partial evaporation of styrene in vacuo or dilution with fresh styrene. Sets of curves presenting the effect of styrene content on the glass transition temperature and the mechanical properties of the cured UPR vs. temperature were presented. Phase separation in the crosslinked UPR with increase in styrene concentration was observed. 

The cross-linking reaction mechanism is also influenced by the presence of other monomers. Methyl methacrylate is often used to improve the uv resistance of styrene-based resins. However, the disparate reaction rates of styrene and methacrylate monomer with the fumarate unsaturation not only preclude the use of more than 8% of the methacrylate monomer due to the significant slowing of the cross-linking reaction but also result in undercured products. 

Through a study of the influence of thiophene and other aromatic compounds on the retardation and chain transfer on the polymerization of styrene by stannic chloride, the relative rates of attack of a carbonium-ion pair could be obtained. It was found that thiophene in this reaction was about 100 times more reactive than p-xylene and somewhat less reactive than anisole. ... 

Gaylord et al. [49] reported the dilution and matrix effects in grafting of the styrene/AN binary mixture onto cellulose with K2S2O8 as the initiator. Titledman and coworkers [50] reported the effect of hydroxypro-pylmethyl cellulose on the course of (NH4)2S20 decomposition and claimed a route for grafting of vinyl monomers onto the polymer backbone. The decomposition of the peroxo salt, under the catalytic influence of the... 

Chu et al. [24] correlated viscosity-morphology and compatibility of PS-PB blends. The effect of styrene-butadiene triblock copolymer in PS-PB was studied, and it was found that the domain size decreases with an increase of compatibilizer loading. The blending methods influenced the morphology due to the difference in the extent of mixing. 

Figure 2 Influence of added styrene-butadiene block copolymer (BCP) on the particle size.

The influence of maleic anhydride modified styrene-(ethylene-co-butylene)-styrene (SEBS) triblock copolymer as a reactive compatibilizer in a nylon-6-SEBS blend was investigated by Wu et al. [66]. When the ma]e-ated SEBS was incorporated into the PA-6-SEBS biend. 

Influence of Structure on the Cationic Polymerization of Substituted Styrenes... 

Substituted styrenes are often used for investigating influences of structure, solvent and initiators on the cationic polymerization 1,2). Under constant outer conditions,... 

One of the few attempts to examine a polymerization reactor in periodic operation experimentally is the work of Spitz, Laurence and Chappelear (X6)who reported the influence of periodicity in the initiator feed to the bulk polymerization of styrene in a CSTR. To induce periodicity the initiator feed was pulsed on-and-off and the reactor output compared with steady-state operation with the same time-averaged initiator input. 

The heterogeneous copolymerization of styrene and acrylonitrile in various diluents as reported by Riess and Desvalois (22). Although the copolymer composition in these studies was not strongly influenced by the diluent choice, the preferential adsorption of acrylonitrile monomer onto the polymer particles shifted the azeotropic copolymerization point from the 38 mole % acrylonitrile observed in solution to 55 mole % acrylonitrile. 

FIGURE 27.8 T-peel strength values of dichloroisocyanurate (DCI)-treated styrene-butadiene rubber (SBR) (R2 rubber) and thermoplastic rubber (TR)/waterbome polyurethane adhesive/canvas joints. Influence of the dichloroisocyanurate (DCI) concentration. (From Cepeda-Jimenez, C.M., Pastor-Bias, M.M., Martfn-Martfnez, J.M., and GottschaUc, P., J. Adhes. Set Technol., 16, 257, 2002.)... 

Romero-Sanchez M.D., Pastor-Bias M.M., and Martm-Martmez J.M., 2002, Improved peel strength in vulcanized SBR rubber roughened before chlorination with trichloroisocyanuric acid, J. Adhes., 78, 15-38. Cepeda-Jimenez C.M., Pastor-Bias M.M., Ferrandiz-Gomez T.P., and Martfn-Martmez J.M., 2001, Influence of the styrene content of thermoplastic styrene-butadiene rubbers in the effectiveness of the treatment with sulfuric acid, Int. J. Adhes. Adhes., 21, 161-172. 

Maleimides Alkyl and aryl maleimides in small concentrations, e.g., 5-10 wt% significantly enhance yield of cross-link for y-irradiated (in vacuo) NR, cw-l,4-polyisoprene, poly(styrene-co-butadiene) rubber, and polychloroprene rubber. A-phenyhnaleimide and m-phenylene dimaleimide have been found to be most effective. The solubihty of the maleimides in the polymer matrix, reactivity of the double bond and the influence of substituent groups also affect the cross-fink promoting ability of these promoters [82]. The mechanism for the cross-link promotion of maleimides is considered to be the copolymerization of the rubber via its unsaturations with the maleimide molecules initiated by radicals and, in particular, by allyfic radicals produced during the radiolysis of the elastomer. Maleimides have also been found to increase the rate of cross-linking in saturated polymers like PE and poly vinylacetate [33]. 

The properties and yield of the polymer product were correlated to the NHC identity, providing clear evidence that the NHC ligand was bound and influenced the reaction. Smaller R groups (Me, Et) on 39-R provided low molecular weights, yields, and detectable amounts of impurity. Sugiyama only examined the influence of sterics on the formation of PC, but the initial success inspired Tanaka and coworkers to extend this application by tethering NHC ligands to styrene beads [48]. 

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