Polystyrene modifiers

High-impact polystyrene (polystyrene modified with styrene-butadiene rubber (SBR) or polybutadiene rubber). 

V. Migonney, C. Baquey, B. Basse-Cathalinat, B. Masson, S. Winnock, D. Ducassou, E. Seme, D. Labarre, C. Fougnot, M. Jozefow/icz, Haemocompatibility of polyethylene-polystyrene modified tubings. Life Support Syst. 1(Suppl 1) (1983) 227-230. 

Other polymers like polypropylene or polystyrene modified by maleic anhydride or maleamide, with the add groups converted to amide, ester or ester chloride and then reacted on Nylon fibers, have been claimed in a Japanese patent (101). Two patents report grafting of olefinic polymers on polycaprolactam (102,103). Grafting of polysiloxanes on polyamides can be induced by X-rays (104). 

Special grades of polystyrene include impact polystyrene modified with ignition-resistant chemical additives. These were developed because of increased emphasis on product safety and used in many electrical and electronic appliances. The addition of flame-retardant chemicals docs not make the polymer noncombustible, but increases its resistance to ignition and decreases the rate of burning when exposed to a minor fire source. 

Impact polystyrene with ignition-resistant additives is used for appliance housings, such as those for television and small appliances. Structural foam impact polystyrene modified with flame-retardant additives is used for business machine housings and m furniture because of its decorability and ease of processing. Consumer electronics, such as cassettes, reels, and housings, is a fast growing area for use of polystyrenes. Medical applicatiuns include sample collectors, petri dishes, and test lubes. 

Polystyrene modified dicyanate polymer was obtained by simultaneous polymerization of styrene monomer and BPA/DC. The handling of low viscous dicyanate solution in styrene is more convenient that the processing of crystalline BPA/DC or high-viscous dicyanate prepolymers [52]. A similar patent specification describes the polymerization of a mixture of styrene, BPA/DC and p-isopropenyl cyanate BMI (cf. Sect. 5) was also used [53]. 

Fig. 3 Plot of Kyi cos 9 vs. yiv for A cleaned and non-cleaned bare silica particles polystyrene modified particles (0.5 um in radius)...

Step 3 and Step 4 di- and tetrahydropyridone derivatives were also prepared by the author without using polystyrene modified reagents and are described. 

Another venue for saccharide display is on solid support. Resins that have been employed include polystyrene beads, polystyrene modified with polyethylene glycol (TentaGel), and... 

Interest in highly cross-linked (20-30% DVB) macroporous polystyrene arose in the early days of oligonucleotide synthesis [158]. It has been argued that this type of support allows for faster reaction kinetics than the low cross-linked gel-type polystyrene. Modified with a trityl-type tinker, it has been tested by Roster and Cramer [159] in the phosphodiester method. The limitations of the chemistry hampered its use for oligomers longer than a few nucleotides. 

Polystyrene-modified natural rubber PP/natural rubber (288)... 

Fig. 6. Derivatograms of polystyrene modified by thiuram and sulphur a - 10 TMTD 20 S, b - 10 TMTD 10 S, c - 10 TMTD 5 S.

Fig. 5 Stress-strain diagram of normal polystyrene (a) and of a polystyrene modified to increase its impact resistance (b)...

Polystyrene modified polyphenylene oxide can be joined with almost all techniques described in this chapter. Snap-fit and press-fit assemblies can be easily made with this material. Maximum strain limit of 8 percent is commonly used in the fiexing member of PPO parts. Metal screw and bolts are commonly used to assemble PPO parts or for attaching various components. 

Polystyrene modified polyphenylene oxide (PPO) or Noryl can be hot plate welded at 260 to 288°C and 20 to 30 s contact time. Unmodified PPO can be welded at hot plate temperatures of 343°C. Excellent spin welded bonds are possible with modified polyphenylene oxide (PPO), because the low thermal conductivity of the resin prevents heat dissipation from the bonding surfaces. Typical spin welding conditions are rotational speed of 40 to 50 ft/min and a pressure of 300 to 400 psi. Spin time should be sufficient to ensure molten surfaces. 

Impact polystyrene n. An alternative name for high impact polystyrene usually polystyrene modified with thermoplastic elastomer to provide a tougher material. See high-impact polystyrene. 

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. 

Figure 21 (a) Structure of the polystyrene-modified cofactor l,n =90 and computer-geuCTated model of the HRP-polystyrene-based... 

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...

Those with the smallest variation in dissipation factor over the 60-10 Hz frequency range are FEP, polyethylene, polystyrene, modified PPO, and the nylons. ... 

SIMS. The biological activity of the polystyrene-modified surfaces was probed with the lectin Alio A, primary rat hepatocytes, and a-2,6-slalyltransferase. 

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