Thermal stability, poly -polystyrene blends

Blends of polystyrene and poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) can be mixed in the melt as both polymers have reasonable thermal stability. There has however been much discussion as to whether the blends are truly one phase. Some techniques suggest homogeneity while others suggest a heterogeneous structure. On balance it appears that the two polymers are in fact thermodynamically miscible in all proportions but completely efficient mixing is difficult to achieve... 

As we said earlier, the introduction of aromatic units into the main chain results in polymers with better thermal stability than their aliphatic analogs. One such polymer is poly(phenylene oxide), PPO, which has many attractive properties, including high-impact strength, resistance to attack by mineral and organic acids, and low water absorption. It is used, usually blended with high-impact polystyrene (HIPS), to ease processability in the manufacture of machined parts and business machine enclosures. 

Composite conductive fibers based on poly(3,4-ethylene-diox)d hiophene]-polystyrene sulfonic acid (PEDOT-PSS) solution blended with polyacrylonitrile (PAN] were obtained via wet spinning. The influence of draw ratio on the morphology, structure, thermal degradation, electrical conductivity, and mechanical properties of the resulting fibers was investigated. The results revealed that the PEDOT-PSS/PAN composite conductive fibers crystallization, electrical conductivity and mechanical properties were improved with the increase of draw ratio. The thermal stability of the fibers was almost independent of draw ratio, and only decreased slightty with draw ratio. Besides, when the draw ratio was 6, the conductivity of the PEDOT-PSS/PAN fibers was 5.0 S cm, ten times the conductivity when the draw ratio was 2 (Fig 5.10]. ... 

In a further smdy, it was investigated if sulfonated low-cost ionomers can also be used as acidic cross-linkers for PBI polymers in order to reduce membrane costs. For this purpose, sulfonated polystyrene (S4a, Fig. 4.5) and poly (a-methylstyrene sulfonic acid), (S4b, Fig. 4.5) have been blended with commercial PBIOO (B4, Fuma-Tech) to 70 wt% PBIOO/30 wt% sulfonated polystyrene blend membranes. The membranes were characterized in terms of chemical stability by the immersion in Fenton s Reagent, thermal stability in terms of TGA-FTIR coupling and in terms of proton conductivity after PA doping [58]. Poly(-a-methylstyrene sulfonic acid) was chosen for comparison with sulfonated polystyrene since it is known that the main radical attack target of polystyrene is the tertiary C-H bond [59] which is not present in poly(a-methylstyrene), leading to verified better radical stabilities of poly(-a-methylstyrene), compared to poly(styrene) [60]. In Table 4.4, the results of thermal and FT stability of the blend membranes B3/S4a and B3/ S4b are listed. 

Melt-mixing in a Brabender Plasticorder, followed by hot pressing, was used to prepare blends of poly(3-octylthiophene) with polyethylene, polystyrene, poly-(ethylene-covinylacetate) and polypropylene [54]. Authors claim that poly(3-octylthiophene) itself is melt processable, but no thermal or rheological properties for this polymer were provided. Thermogravimetric analysis of this polymer with different stabilization... 

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