Polymer high-impact polystyrene

The oxidative coupling of 2,6-dimethylphenol to yield poly(phenylene oxide) represents 90—95% of the consumption of 2,6-dimethylphenol (68). The oxidation with air is catalyzed by a copper—amine complex. The poly(phenylene oxide) derived from 2,6-dimethylphenol is blended with other polymers, primarily high impact polystyrene, and the resulting alloy is widely used in housings for business machines, electronic equipment and in the manufacture of automobiles (see Polyethers, aromatic). A minor use of 2,6-dimethylphenol involves its oxidative coupling to... 

Dynamic Mechanical Behaviour of Atactic Polystyrene, High-impact Polystyrene and Other Styrenic Polymers... 

There are a number of flame-retardant styrenic polymers that will be covered in this chapter. These include polystyrene itself, rubber-modified polystyrene [high-impact polystyrene (HIPS)] and rubber-modified styrene-acrylonitrile copolymer [acrylonitrile-butadiene-styrene (ABS)]. Blends with styrenic... 

In rubber-modified polymers like high impact polystyrene or acrylonitrile-butadiene-styrene (ABS) resins, the toughening effect of the dispersed rubber particles appears only in the presence of block or graft copolymers. These copolymers regulate the particle size of the rubber dispersion and achieve adhesion of the two phases. Hence, graft copolymers are of practical importance in polymer alloys. 

The stiffness of such a composite is close to the Hashin-Shtrikman lower bound for isotropic composites. Even if the spherical particles are perfectly rigid compared with the matrix, their stiffening effect at low concentrations is modest. Conversely, when the inclusions are more compliant than the matrix, spherical ones reduce the stiffness the least and platelet ones reduce it the most. Indeed, soft platelets are suggestive of crack-like defects. Soft platelets, therefore result not only in a compliant composite, but also a weak one. Soft spherical inclusions are used intentionally as crack stoppers to enhance the toughness of polymers such as polystyrene (high impact polystyrene), with a small sacrifice in stiffness. 

A graft polymer chain (Fig. 4c) has a linear backbone and randomly distributed side chains. The side chains (which can be very long) are structurally distinct from the main chain but can be homopolymers or copolymers. A well-known example of a graft polymer is high-impact polystyrene (HIPS), where polybutadiene (PB) side chains are grafted to the PS backbone. 

Recommended for polymers PS ( high impact, crystalline polystyrene), ABS, PC, PVC ... 

Immiscible blends include toughened polymers in which an elastomer is added, existing as a second phase. The addition of the elastomer phase dramatically improves the toughness of the resulting blend. Examples of toughened polymers include high-impact polystyrene, modified PP, ABS, PVC, nylon, and others. In addition to toughened polymers, a variety of other two-phase blends are commercially available. These include PC-PBT, PVC-ABS, PC-PE, PP-EPDM, and PC-ABS. 

X. X. Zheng and C. A. Wilkie, Nanocomposites based on poly(epsilon-caprolactone) (PCL)/clay hybrid Polystyrene, high impact polystyrene, ABS, polypropylene and polyethylene. Polymer Degradation and Stability, 82 (2003), 441-50. 

The impact on the PHRR when substituting a polymer oligomer as a surface treatment on montmorillonite for a quaternary ammonium ion is not a panacea [51,52]. The comparison of methylmethacrylate oligomer-treated montmorillonite with quat-treated montmorillonite in poly(methylmethacrylate), polystyrene, high-impact polystyrene, acrylonitrile-butadiene-styrene terpolymer, polypropylene, and polyethylene nanocomposites indicated sensitivity to polymer type and a poor correlation to the degree of exfoliation determined by X-ray analysis and TEM. The impact of polymer structure associated with the montmorillonite appears to be a significant variable relating to the PHRR of these composites. In this book, chapter 4 on barriers... 

Figure 3.25 In situ deformation of a rubber-toughened polymer (HIPS - high impact polystyrene) (a) overview of the area under load and (b) area in front of a crack tip (in micrograph (a) at the bottom) with rubber particles (gray) in a matrix (black) with crazes (bright) 2-pm-thick deformed section, deformation direction see arrow, in lOOOkV HEM.

Polystyrene. Polystyrene [9003-53-6] is a thermoplastic prepared by the polymerization of styrene, primarily the suspension or bulk processes. Polystyrene is a linear polymer that is atactic, amorphous, inert to acids and alkahes, but attacked by aromatic solvents and chlorinated hydrocarbons such as dry cleaning fluids. It is clear but yellows and crazes on outdoor exposure when attacked by uv light. It is britde and does not accept plasticizers, though mbber can be compounded with it to raise the impact strength, ie, high impact polystyrene (HIPS). Its principal use in building products is as a foamed plastic (see Eoamed plastics). The foams are used for interior trim, door and window frames, cabinetry, and, in the low density expanded form, for insulation (see Styrene plastics). 

In the mid-1950s a number of new thermoplastics with some very valuable properties beeame available. High-density polyethylenes produced by the Phillips process and the Ziegler process were marketed and these were shortly followed by the discovery and rapid exploitation of polypropylene. These polyolefins soon became large tonnage thermoplastics. Somewhat more specialised materials were the acetal resins, first introduced by Du Pont, and the polycarbonates, developed simultaneously but independently in the United States and Germany. Further developments in high-impact polystyrenes led to the development of ABS polymers. 

Following the success in blending rubbery materials into polystyrene, styrene-acrylonitrile and PVC materials to produce tough thermoplastics the concept has been used to produce high-impact PMMA-type moulding compounds. These are two-phase materials in which the glassy phase consists of poly(methyl methacrylate) and the rubbery phase an acrylate polymer, usually poly(butyl acrylate Commercial materials of the type include Diakon MX (ICI), Oroglas... 

As mentioned earlier, unmodified polystyrene first found application where rigidity and low cost were important prerequisites. Other useful properties were the transparency and high refractive index, freedom from taste, odour and toxicity, good electrical insulation characteristics, low water absorption and comparatively easy processability. Carefully designed and well-made articles from polystyrene were often found to be perfectly suitable for the end-use intended. On the other hand the extensive use of the polymers in badly designed and badly made products which broke only too easily caused a reaction away from the homopolymer. This resulted, first of all, in the development of the high-impact polystyrene and today this is more important than the unmodified polymer (60% of Western European market). 

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