Polymers blending polyphenylenes

In polymers such as polystyrene that do not readily undergo charring, phosphoms-based flame retardants tend to be less effective, and such polymers are often flame retarded by antimony—halogen combinations (see Styrene). However, even in such noncharring polymers, phosphoms additives exhibit some activity that suggests at least one other mode of action. Phosphoms compounds may produce a barrier layer of polyphosphoric acid on the burning polymer (4,5). Phosphoms-based flame retardants are more effective in styrenic polymers blended with a char-forming polymer such as polyphenylene oxide or polycarbonate. 

The advances in polymer blending and alloying technology have occurred through three routes (1) similar-rheology polymer pairs, (2) miscible polymers such as polyphenylene oxide and polystyrene, or (3) interpenetrating polymer networks (IPNs). All these systems were limited to specific polymer combinations that have an inherent physical affinity for each other. However with... 

Research Focus Method for preparing intimately mixed polymer blends of nylon-66 and polyphenylene sulfide. 

Polymer blends can be subdivided into two kinds those of compatible and those of incompatible polymers. Real compatibility is an exception (see 9.1) an example is PS with PPE (polyphenylene ether, also called PPO, polyphenylene oxide). These two polymers can be blended with each other on such a small scale that it really looks like molecular miscibility. This blend shows, therefore, only one single glass transition. 

Polymer Blends. Blending of polymers with each other accounts for approximately 40 percent of the present plastics market, and the practice is growing continually, because it permits the development of improved properties without the cost of inventing new polymers. When polymers are fairly miscible, as in the polyethylenes, and in polyphenylene ether plus polystyrene, blending can be used to produce intermediate properties and balance of properties. Most polymer blends... 

This review summarizes our work at the University of Bayreuth over the last few years on improving the electret performance of the commodity polymer isotactic polypropylene (Sect. 3) and the commodity polymer blend system polystyrene/polyphenylene ether (Sect. 4) to provide electret materials based on inexpensive and easily processable polymers. To open up polymer materials for electret applications at elevated temperatures we concentrated our research on commercially available high performance thermoplastic polyetherimide resins and synthesized several fluorinaled polyetherimides to identify structure-property relations and to improve further the performance at elevated temperatures (Sect. 5). 

J. M. Joyce and D. J. Kelley. Polyphenylene ether-alkenyl aromatic polymer blends having organobromine additives. US Patent 4927 858, assigned to Huntsman Chemical Corporation (Salt Lake City, UT), May 22,1990. 

Lee HJ, Suda H, Haraya K, Moon SH. Gas permeation properties of carbon molecular sieving membranes derived from the polymer blend of polyphenylene oxide (PPO)/polyvin-ylpyrrolidone (PVP). J Membr Sci 2007 296(1-2) 139-46. 

Polyphenylene ether (PPE) and polystyrene Partially incompatible polymer blends Polyethylene and polyisobutylene Polyethylene and polypropylene (5% PE in PP) Polycarbonate and polybutylene terephthalate... 

For small concentrations of a given component in a polymer blend (less than 10 wt%), the resulting weak transition is typically very difficult to resolve using conventional DSC or DMTA [5,15]. Using MTDSC, Tg determinations were performed [32] on a physical blend containing four components pure PS plus PPO-30 (a PS/polyphenylene oxide (PPO) blend at a composition ratio of 70/30) plus PPO-70 (a PS/PPO blend at a composition ratio of 30/70) plus pure PPO. The amount of each component was 44.0 7.1 13.4 34.5, by weight. Figure 3.9 shows both the heat capacity and... 

Polymer blends were developed alongside the emerging polymers. Once nitrocellulose (NC) was invented, it was mixed with NR. Blends of NC with NR were patented in 1865 - 3 years before the commercialization of NC. The first compatibilization of polyvinylchloride (PVC) by blending with poly vinylacetate (PVAc) and their copolymers dates from 1928. PVC was commercialized in 1931, while its blends with nitrile rubber (NBR) were patented in 1936 - 2 years after the NBR patent was issued. The modem era of polymer blending began in 1960, after Alan Hay discovered the oxidative polymerization of 2,4-xylenols that led to polyphenylene ether (PPE). Its blends with styrenics, Noryl , were commercialized in 1965. 

The commercial PPO resins were developed by General Electric (Noryl) and defined as modified PPO. Their exact chemical nature is unknown. They may be polymer blends, likely with polystyrene or high-impact polystryene. In Europe PPO is recognized by a more generic name, polyphenylene ether (PPE). 

The second case we describe here is the polymerization of styrene to polystyrene in the presence of polyphenylene oxide. Poly-2,6-dimethyl-l,4-phenylene oxide (PPE) is an orange-red polymer with a glass transition temperature of 220°C and it is completely miscible with PS. Although strictly speaking the system consists of two components, the mutual complete miscibility of all components (monomer as well as both polymers) permits to treat this polymerization as a one-component reactive extrusion process. From product point of view the addition of PPE to PS results in a polymer blend with a higher glass transition temperature (6) than polystyrene. From process point of view the increased viscosity of PPO... 

Polymer blends as products have been the result of billions of dollars of research and technology development expenditures. By 1982, the per annum worldwide sales of polyphenylene/polystyrene exceeded US 1 billion. Polyvinyl chloride/ acrylonitrile butadiene styrene (ABS) blends have captured the markets worldwide. Compatibilized nylon/ABS blends appeared on the market and were sold under the name Triax 1000 by Monsanto with step-change improvement in product performance properties. 

Thanks to their unusual miscibility polymer blends of polyphenylene oxide and polystyrene were the first commercially successful amorphous engineering thermoplastics blends, introduced back, in 1968 Pete Juliauo of GE Corporate Research Laboratories presented a comprehensive review at the last lUPAC Meeting of The Rague(l) where he showed how the evolution of science and technology of blends (2,3) based on polyphenylene oxide, blsphenol A polycarbonate, polybutylene teraphthalate, polyamides and polyacetals, created many more opportunities for the development of engineering thermoplastics with attractive combination of attributes. 

FTIR spectroscopy has been applied in the study of polymer blends including Neoprene rubber, chlorosulfonated PE, nitrile rubber, polyvinyl chloride (PVC) containing carbon black and other fillers [86], Nylon 6 inorganic [87], polyhydroxyether sulfone/poly(N-vinyl pyrrolidone) [88], graphite-based low-density polyethylene [89], caprolactone/Nafion blends [90], polybutylene terephthalate/polyamide [91], polyphenylene sulfide/acrylonitrile - butadiene - styrene [92], PMMA/polypyrrol [93], and lower or high performance liquid chromatography (LDPE/HDPE) [94]. 

Amorphous polyamides, preferably copolyamides from iso- and terephthalic acid with hexamethylene diamine have gained importance as components in polymer blends with polycarbonate, polyphenylene ether and/or functionalized elastomers, and also with the semi-crystalline polyamides 6 and 66. These copolyamides increase the chemical resistance of polycarbonate or polyphenylene ether and reduce stress-cracking sensitivity to concentrated zinc chloride solution in polyamide 6 and 66. Moreover, these copolyamides provide for improved compatibility. 

Polyamides are the dominant polymers used for mirror housings, with 3,400 metric tons consumed in vehicle exteriors manufactured in North America in 2000. Polyphenylene oxide/polyamide filled with carbon fibers was recently introduced to provide charge dissipation during the electrostatic painting process of mirror housings. As with PPO/PA body panels, this semiconductive polymer blend ensures high paint-transfer efficiency while eliminating the need to apply a separate conductive primer (Fig. 15). 

S. M. Duff, An investigation into the crystallization mechanisms of semi-crystalline polymer blends Syndiotacticpolystyrene blended with polyphenylene ether, in M.Sc. Thesis. University of Limerick Limerick (1998). 

Common conductive polymers are poly acetylene, polyphenylene, poly-(phenylene sulfide), polypyrrole, and polyvinylcarba2ole (123) (see Electrically conductive polymers). A static-dissipative polymer based on a polyether copolymer has been aimounced (124). In general, electroconductive polymers have proven to be expensive and difficult to process. In most cases they are blended with another polymer to improve the processibiUty. Conductive polymers have met with limited commercial success. 

The uses of blends of polystyrene with the so-called polyphenylene oxide polymers are discussed in Chapter 21. 

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