Polystyrene—polyethylene blends, mechanical

Kung, E. Lesser, A. J. and McCarthy, T. J. (1997) Mechanical properties of polystyrene/polyethylene blends prepared by using supercritical CO2 processing, ACS Polymer Preprints, 38,462-463. 

Couman W.J., Heikens D., and Sjoerdsma S.D., Dilatometric investigation of deformation mechanism in polystyrene-polyethylene block copolymer blend Correlation between Poisson ratio and adhesion. 

Barensten, W. M. Heikens, D. Mechanical Properties of Polystyrene/Low Density Polyethylene Blends. Polymer 1973, 14, 579. 

Sanchez-Solis, A. Estrada, M.R. Cruz, J. Manero, O. On the properties and processing of polyethylene terephthalate/styrene-butadiene rubber blend. Polym. Eng. Sci. 2000,40 (5), 1216-1225. Luzinov, I. Xi, K. Pagnoulle, C. Huynh-Ba, G. Jerome, R. Composition effect on the core-shell morphology and mechanical properties of ternary polystyrene/styrene butadiene rubber polyethylene blends. Polymer 1999, 40 (10), 2511-2520. 

Styrene is polymerized in the presence of butadiene rubber. Polystyrene and polyethylene are mechanically mixed in the presence of compatibilizer according to special technology. COMPATIBILIZATION Compatibilizer miscible with both pol3nners BLEND MANUFACTURE Extrusion... 

Weld lines and mechanical properties of injection molded polyethylene/polystyrene/copolymer blends. Polym. Eng. Sci.. 34,1202-1210. 

We focus here on the polystyrene/high-density polyethylene (HDPE) system. We have studied this system in greater detail than any other and describe here the phase behavior of this system, the blend synthesis, and some mechanical properties of the composites. 

Mechanical tests indicate that these blends do not behave like conventional blends and suggest that the polystyrene phase is continuous in the substrate. The moduli of the blends as a function of blend composition is plotted in Figure 10.6. The Voigt and Reuss models are provided for comparison (Nielsen, 1978) These are the theoretical upper and lower bounds, respectively, on composite modulus behavior our data follows the Voigt model, suggesting that both the polystyrene and polyethylene phases are continuous. In most conventional composites of polystyrene and HDPE, the moduli fall below the Voigt prediction indicating that the phases are discontinuous and dispersed (Barentsen and Heikens, 1973 Wycisk et al., 1990). 

Figure 10.7 shows that the tensile strength is improved as polystyrene is incorporated. Data for conventional melt-blended samples (Fayt et al., 1989) are provided for comparison. We note that the ductile-to-brittle transition for our system is shifted toward much higher polystyrene content. Fayt and others have shown that conventionally prepared polyethylene/ polystyrene blends are relatively poor materials (Barentsen and Heikens, 1973 Wycisk et al., 1990). Blends of most compositions are weaker than polystyrene or polyethylene homopolymers because of the poor interfacial adhesion between the two immiscible polymers. The electron micrographs and the mechanical data for the blends described here indicate that poly-... 

Fayt, R. Jerome, R. Teyssie, P. Molecular Design of Multicomponent Polymer Systems. XIV. Control of the Mechanical Properties of Polyethylene-Polystyrene Blends by Block Copolymers. J. Polym. Sci., Part B Polym. Phys. 1989, 27, 775. 

These experimental mixers enabled the study of the role of the rheological properties of the individual blend components on the mechanisms and rates of dispersive mixing. Three commercial polymers Dow Chemical Company polystyrene (PS686) and low density polyethylene (PE 132) and Chevron low density polyethylene (PE 1409) were used in the study. Figure 11.32 (a) shows the viscosities of the three polymers at 200°C (121). PS 685... 

Fayt R, Jerome R, Teyssie P (1989) Molecular design of multicomponent polymer systems. XIV Control of the mechanical properties of polyethylene-polystyrene blends by block copolymers. J Poly Sci Part B Poly Phys 27(4) 775-793... 

On the other hand, some mechanically compatible blends as well as some dispersed two-phase systems have made respectable inroads into the commercial scene. Many of these are blends of low-impact resins with high-impact elastomeric polymers examples are polystyrene/rubber, poly (styrene-co-acrylonitrile) /rubber, poly (methyl methacrylate) /rubber, poly (ethylene propylene)/propylene rubber, and bis-A polycarbonate/ ABS as well as blends of polyvinyl chloride with ABS or PMMA or chlorinated polyethylene. 

Failure Mechanisms in Blends of Linear Low-Density Polyethylene and Polystyrene... 

Specifically, PVC blends with polyethylene, polypropylene, or polystyrene could offer significant potential. PVC offers rigidity combined with flammability resistance. In essence, PVC offers the promise to be the lowest cost method to flame retard these polymers. The processing temperatures for the polyolefins and polystyrene are within the critical range for PVC. In fact, addition of the polyolefins to PVC should enhance its ability to be extruded and injected molded. PVC has been utilized in blends with functional styrenics (ABS and styrene-maleic anhydride co-and terpolymers) as well as PMMA offering the key advantage of improved flame resistance. Reactive extrusion concepts applied to PVC blends with polyolefins and polystyrene appear to be a facile method for compatibilization should the proper chemical modifications be found. He et al. [1997] noted the use of solid-state chlorinated polyethylene as a compatibilizer for PVC/LLDPE blends with a significant improvement in mechanical properties. A recent treatise [Datta and Lohse,... 

As stated previously, styrene-diene triblock copolymers are the most important category of thermoplastic elastomers. Unlike most other TPEs, they can be blended with large quantities of additives without a drastic effect on properties. In almost all applications, the actual triblock copolymer content is less than 50%. Oils are used as a processing aid and do not result in a significant loss of properties if the polystyrene domains are not plasticized. For this reason, naphthalenic oils are preferred. The use of inert fillers such as clays or chalks reduces the cost of the final material. Unlike conventional rubbers, inert fillers do not have a substantial effect on the mechanical properties of TPEs. Thermoplastics such as polyethylene or polypropylene are also used to improve the solvent resistance and can increase the upper service temperature. Polystyrene homopolymer is used as a processing aid, which also increases the hard phase weight fraction and causes the material to stiffen. 

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