Polystyrene with butadiene

Super-high-impact polystyrene can be made from blends of polystyrene with butadiene-styrene block copolymers. As illustrated in Figure 2.4, the morphology of rubber-containing domains is finer than the high-impact polystyrene structure shown in the upper left of Figure 2.3. The subject has been recently reviewed by Aggarwal and Marti and Riess. ... 

In the case of poly(vinyl chloride) plastics, the FWA is mixed dry with the PVC powder before processing or dissolved in the plasticising agent (see Vinyl polymers). Polystyrene, acrylonitrile—butadiene—styrene (ABS), and polyolefin granulates are powdered with FWA prior to extmsion (2,78) (see... 

Another polyolefin of interest is polystyrene, a clear, brittle plastic that, by itself, is rarely used in composites. However, several copolymers and alloys of polystyrene with acrylonitrile or butadiene have been used with fiber glass or glass spheres to form composites (7). 

Cheap moulded objects. Toughened with butadiene to moke high-impact polystyrene (FIIPS). Foamed with CO2 to moke common packaging. 

Transparent toughened polystyrene polymers are produced by blending polystyrene with SBS block copolymers (see Section 11.8). During the 1970s and 1980s most development was with block copolymers with a radial (or star) shape. Two types were developed block copolymers with a central butadiene block, and block copolymers with a central polystyrene block. 

Polystyrene (PS) is the fourth big-volume thermoplastic. Styrene can be polymerized alone or copolymerized with other monomers. It can be polymerized by free radical initiators or using coordination catalysts. Recent work using group 4 metallocene combined with methylalumi-noxane produce stereoregular polymer. When homogeneous titanium catalyst is used, the polymer was predominantly syndiotactic. The heterogeneous titanium catalyst gave predominantly the isotactic. Copolymers with butadiene in a ratio of approximately 1 3 produces SBR, the most important synthetic rubber. 

Polystyrene One of the high volume plastics, is relatively low in cost, easy to process, has sparkling clarity, and low water absorption. But basic form (crystal PS) is brittle, with low heat and chemical resistance, poor weather resistance. High impact polystyrene is made with butadiene modifiers provides significant improvements in impact strength and elongation over crystal polystyrene, accompanied by a loss of transparency and little other property improvement. PS is used in many different formulations. 

About half of the styrene produced is polymerized to polystyrene, an easily molded, low-cost thermoplastic that is somewhat brittle. Foamed polystyrene can be made by polymerizing it in the presence of low-boiling hydrocarbons, which cause bubbles of gas in the solid polymer after which it migrates out and evaporates. Modification and property enhancement of polystyrene-based plastics can be readily accomplished by copolymerization with other substituted ethylenes (vinyl monomers) for example, copolymerization with butadiene produces a widely used synthetic rubber. 

Styrene co-butadiene is a rubbery amorphous polymer with a glass transition temperature well below room temperature. Polystyrene co-butadiene is an important component of several commercial families of plastic that contain polystyrene blocks. 

Block copolymers of polystyrene with rubbery polymers are made by polymerizing styrene in the presence of an unsaturated rubber such as 1,4 polybutadiene or polystyrene co-butadiene. Some of the growing polystyrene chains incorporate vinyl groups from the rubbers to create block copolymers of the type shown in Fig. 21.4. The combination of incompatible hard polystyrene blocks and soft rubber blocks creates a material in which the different molecular blocks segregate into discrete phases. The chemical composition and lengths of the block controls the phase morphology. When polystyrene dominates, the rubber particles form... 

Transparent block copolymers of styrene and butadiene, having polystyrene character (Phillips). Weather-resistant, impact-resistant polystyrene with EPDM rubber (Mitsui Toatsu, Hoechst). 

The original objective in preparing emulsion polymers from the 2,6-dichlorostyrene and acenaphthylene was to obtain polymeric fillers of higher Tg than that of polystyrene. It was also presumed that these fillers would not be bonded chemically to the rubber during vulcanization and that the copolymers with butadiene would enable such bonding to be effected. Actually, the polydichlorostyrene and polyacenaphthylene did become bonded to the rubber, as indicated by the inability to extract most of the filler by solvents. The final result was that the copolymers with butadiene served merely as fillers of lower Tg than the above homo-... 

Fig. 3. Example of electron micrograph of a hexagonal structure. Copolymer polystyrene-poly-butadiene SB. 32 containing 30,5% of polybutadiene, swollen with 29% of MMA and post-polymerized. Main figure section along the plane perpendicular to the direction of the axis of the insoluble poly butadiene cylinders insert section by a plane parallel to the axis of the cylinders. Polybutadiene stained by osmium tetroxide in dark...

PVC can be blended with numerous other polymers to give it better processability and impact resistance. For the manufacture of food contact materials the following polymerizates and/or polymer mixtures from polymers manufactured from the above mentioned starting materials can be used Chlorinated polyolefins blends of styrene and graft copolymers and mixtures of polystyrene with polymerisate blends butadiene-acrylonitrile-copolymer blends (hard rubber) blends of ethylene and propylene, butylene, vinyl ester, and unsaturated aliphatic acids as well as salts and esters plasticizerfrec blends of methacrylic acid esters and acrylic acid esters with monofunctional saturated alcohols (Ci-C18) as well as blends of the esters of methacrylic acid butadiene and styrene as well as polymer blends of acrylic acid butyl ester and vinylpyrrolidone polyurethane manufactured from 1,6-hexamethylene diisocyanate, 1.4-butandiol and aliphatic polyesters from adipic acid and glycols. 

The potential problem of styrene taint in foods is well known and documented in the literature (Saxby 1996). Styrene (see Chapter 2) is the monomer that is polymerized to make polystyrene (PS) (also known as general purpose or GPPS grade). It is also commonly used with butadiene rubber (5-20 % w/w) as a block copolymer to form high impact polystyrene (HIPS). In addition there are less common copolymer grades such as acrylonitrile-butadiene-styrene (ABS) having a mixture of 25 %, 15-25 % and 50-65 % of each monomer respectively or a copolymer with acrylonitrile (styrene-acrylonitrile, SAN). 

The copolymerization with alkyllithium to produce uniformly random copolymers is more complex for the solution process than for emulsion because of the tendency for the styrene to form blocks. Because of the extremely high rate of reaction of the styryl-lithium anion with butadiene, the polymerization very heavily favors the incorporation of butadiene units as long as reasonable concentrations of butadiene are present. This observation initially was somewhat confusing because the homopolymerization rate of styrene is seven times that for butadiene. However, the cross-propagation rate is orders of magnitude faster than either, and it therefore dominates the system. For a 30 mole percent styrene charge the initial polymer will be almost pure butadiene until most of the butadiene is polymerized. Typically two-thirds of the styrene charged will be found as a block of polystyrene at the tail end of the polymer chain ... 

An other interesting example of copolymer is given by Georges et al. [52,59] who first demonstrated the living character of the polymerization of styrene initiated by dibenzoyl peroxide in the presence of Tempo or Proxyl (2,2,5,5-tetramethyl-l-pyrrolydinyloxy). Polystyrene with a narrow polydispersity (Mw/Mn = 1.2) is obtained and block copolymers with butadiene, isoprene, acrylate and methacrylate sequences are prepared ... 

Van Henten, at the Shell Plastic Laboratories (II), showed that styrene-butadiene block polymers can be blended with commercial HIPS to upgrade its impact strength to 5.8 ft-lbs/inch. Childers, at Phillips Petroleum (12), blended commercial polystyrene with block polymers in a Brabender plastograph. To control rubber particle size he added a peroxide during the blending operation, thereby creating crosslinks. With this technique he achieved an impact strength of 5.9 ft-lbs/inch. 

Polystyrene (PS) in its atactic and syndiotactic forms is a brittle thermoplastic, even in an orientated state [4]. To improve the toughness of aPS, impact modification has been practised for a long time, either by polymerizing the styrene in the presence of a polybutadiene rubber leading to high-impact polystyrene, commonly called HIPS, or by blending the polystyrene with multi-block copolymers, mainly of the styrene-butadiene-styrene (S-B-S) type. 

An urethane-based pressure-sensitive adhesive composed of a liquid hydroxytelechelic polybutadiene and a polyisocyanate does not require a solvent in coatings onto label sheets. This polymer together with the (polystyrene-co-butadiene) copolymer and a polyisocyanate was applied in steel coatings 239 240>. 

Polystyiene-polybutadiene Polybutadiene-poly(a-methyl styrene) Polybutadiene-poly(vinyl naphthalene) Polystyrene-polybutadlene-polystyrene Polybutadiene-polystyrene-polybutadiene Polystyrene-polyisoprene Pblystyrene-polyisoprene-polystyrene Polyia>prene-poly(vinyl-2-p dine) PofyiK>prene-poly(vinyl-4-pyridine) Polyisoprene-poly(methyl methacrylate) Polystyrene-poly(butadiene or ia>prene)-polystyrene Star polystyrene-polybutadiene with 4 branches Star polybutadiene-polystyrene with n branches Star polystyrene-polybutadiene with n branches Star polystyrene-polyisoprene with n brandies Polystyrene-polyisoprene-poly(vinyl-2-pyridine) Polystyrene-poly vinyl-2-pyridine) Polystyrene-poly(vinyl-4-pyridine) Poly(vinyl-2-pyridine)-poly(vinyl-4-pyridine)... 

Styrene copolymer with divinylbenzene is used frequently in many polystyrene products, and the similarity between the two comonomers makes this copolymer almost identifiable with the homopolymer itself. In terms of production volume, styrene copolymer with butadiene is probably the most important copolymer (SBR). Depending on the butadiene/styrene ratio, the copolymer is used as an elastomer with large applications in the tire industry, in the manufacturing of conveyor belts, etc. when butadiene/styrene ratio is 75/25 parts wt., or when butadiene/styrene ratio is 40/60 parts... 

Used as an antioxidant and thermostabilizer for polypropylene, polyethylene, impact resistant polystyrene, poly-4-methyl-pentene. Can be used as a stabilizer for natural and synthetic rubber, polyvinyl chloride. A copolymer of acrylonitrile with butadiene and styrene, polyacetals, alkyde resins, polyamides and polyesters. 

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