Polystyrene hydrocarbon polymers

The pure hydrocarbon nature of polystyrene gives it excellent electrical insulation characteristics, as a result of both the fundamentally good characteristics of the material and to the low water absorption of such a hydrocarbon polymer. The insulation characteristics are therefore well maintained in humid conditions. 

Nonconjugated hydrocarbon polymers could also be combined with carbon nanotubes, with polystyrene being the most studied example. The composites are generally prepared by solution or shear mixing techniques, resulting in materials with improved mechanical properties [60]. 

Several workers have used this approach to metalate hydrocarbon polymers. Plate and co-workers (98), for example, metalated polystyrene and monitored the butane evolution by gas chromatography. They reported a 40% catalyst efficiency. However, they did not report the grafting efficiency or the overall effectiveness of this metalating reagent. 

Despite the numerous papers devoted to photooxidation of hydrocarbon polymers [21], the initiation step has not been clearly established yet even for polyethylene or polystyrene which were the most studied [22,23]. Difficulties which follow from solution of this problem consist in the necessity of analysis of small amounts of decomposing unstable structures and products which are thereby formed. Moreover, photoinitiation does not include one reaction only but the overall complex of many chemical and physical processes, which importance depends on experimental conditions. 

Since the initial work of Smidsrod and Guillet numerous investigators have used I.G.C. to determine physicochemical parameters characterising the interaction of small amounts of volatile solutes with polymers Baranyi has shown that infinite dilution weight fraction activity coefficients, interaction parameters and excess partial molar heats of mixing can be readily determined with this technique. Partial molar heats and free energies of mixing, and solubility parameters of a wide variety of hydrocarbons in polystyrene and poly(methyl methacrylete) have been determined The temperature dependence of the interaction parameter between two polymers has also been studied... 

The analytical depth profiling for these systems (e.g. the polystyrene data is shown in Figure 5) revealed that the reaction is essentially confined to the topmost monolayer of material ( ). This is entirely reasonable in terms of the plasma chemistry since the most prominent reactive species is atomic oxygen f ich is expected to have an extremely short mean free path in hydrocarbon polymers. This serves as a very good example of the powerful nature of XPS when applied to the study of the surface modification of polymers. 

Methods have been developed for the analysis of hydrocarbon polymers (e.g. styrene, butadiene and isoprene) by MALDI-TOF-MS, through the attachment of Ag(acac) to matrices of tran5-3-indoleacrylic acid or l,4-bis(2-(5-phenyloxazolyl))benzene . SUver-cationized molecular ions were produced for polymers of styrene, butadiene and isoprene up to mass 125,000 Da. For lower-mass styrene polymers, the resolved oligomer molecular ions provide information concerning the end group. This technique permits the analysis of many commercially important materials such as acrylonitrile-butadiene-styrene (ABS), styrene-acrylonitrile, styrene-methyl methacrylate and styrene-isoprene copolymers. The use of the salts of transition metals other than Ag, Cu or Pd as the cationizing agents fails to cationize polystyrenes in MALDI. The ability of MALDI to reduce metals to the oxidation state 4-1 is critically important to polystyrene cationization, as without this reduction MALDI tends to fail to form polystyrene-metal cations. Cu(acac)2 was used for the verification of the above . 

Hydrocarbon polymers that were exposed in the LEO environment invariably showed an increase in surface oxide content. For example, the oxygen atomic concentration on a polyethylene surface increased by roughly 10 percent during exposure in LEO. And similar exposures of polystyrene and Kapton led to an increase in surface oxygen atomic concentration of approximately 20 percent and three percent, respectively. 67... 

It is well known that individually, photoinitiators and certain metallic organic compounds cause hydrocarbon polymers, such as polyethylene or polystyrene, to photodegrade faster than the original polymer not containing such an additive. We have discovered that by combining both types of additives in a plastic a striking synergistic effect occurs. 

An interesting extension of our work is the possibility to blend some of the more rodlike hydrocarbon LC polymers with other flexible random coil all-hydrocarbon polymers such as polystyrene or polyethylene. Depending on both the transition temperatures and solubilities, some mixtures may form phase separated immiscible blends and ultimately generate "molecular composites". 

Generally, the intensity of ion peaks decreases with increasing ion mass. For hydrocarbon polymers containing cyclic ions (aromatic hydrocarbon polymers) such as polystyrene, which... 

DSC analysis of the polymer revealed a higher Tg (178 °C) than those of many other known hydrocarbon polymers, such as thermally resistant syn-diotactic polystyrene. The polymer does not decompose up to 300 °C in the TG analysis and shows good thermal stability. These results as well as the 13C NMR data indicate a rigid polymer structure. 

The polyethylene latexes obtained in the different emulsion polymerization procedures using the various aforementioned nickel(II) complexes display average particle diameters of 100 to 600 nm. A number of anionic surfactants or neutral stabilizers are suitable, i.e. compatible with the catalysts and capable of stabilizing the latex. Solids contents of up to 30% have been reported to date. A typical TEM image is shown in Fig. 7.2. By comparison to smooth, spherical latex particles of amorphous polystyrene as a well studied hydrocarbon polymer prepared by free-radical emulsion polymerization, the ruggedness of the particles shown can be rationalized by their high degree of crystallinity. 

Adding AgN03 to solutions of hydrocarbon polymers before analysis by laser-desorption FT-MS allows efficient Ag ion chemical ionization. This was applied to polystyrene (187), polyisoprene (188), polybutadiene (189) and polyethylene (190). Oligomers attached to Ag+ were observed with m/z values ranging from 400 to 6000 D, with unit mass resolution256. 

Polystyrene (pol-ee-STYE-reen) is a thermoplastic polymer made from styrene. A thermoplastic polymer is a material that can he repeatedly softened and hardened by alternately heating and cooling. Styrene is a hydrocarbon derived from petroleum with the formula C6H5CH=CH2. The presence of the double bond in the styrene molecule makes it possible for styrene molecules to react with each other in long chains that constitute the polymer polystyrene. 

Derrick and coworkers have investigated polyglycols (PEG, polybutadiene,polystyrene, and poly(methylmethacrylate) by FD-MS. Prokai and Scrivens et al. have looked at various phenol-formaldehyde (novalak and resole) resins. Wile and Cook obtained FD spectra of lactone, lactam, and carbonate polymers." Matsuo et al. investigated polystyrene and poly(propylene glycol) as high mass reference compounds." Faffimer and Schulten studied several hydrocarbon polymers (polybutadiene, polyiso-prene, polyethylene, polystyrene)." Evans et al. used FD-MS to investigate mechanistic aspects of fhe mefal-cafalyzed polymerization of ethylene and other olefins. 

Aliphatic or side-chain aromatic hydrocarbon polymers (polyolefins and polystyrene) give no char while the CR percentage of main-chain aromatic, condensed aromatic, heterocyclic (high-temperature) polymers may be as high as 70%. Halogen-containing polymers are outside the scope of the above relation. 

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