Noryl

Physical or chemical vapor-phase mechanisms may be reasonably hypothesized in cases where a phosphoms flame retardant is found to be effective in a noncharring polymer, and especially where the flame retardant or phosphoms-containing breakdown products are capable of being vaporized at the temperature of the pyrolyzing surface. In the engineering of thermoplastic Noryl (General Electric), which consists of a blend of a charrable poly(phenylene oxide) and a poorly charrable polystyrene, experimental evidence indicates that effective flame retardants such as triphenyl phosphate act in the vapor phase to suppress the flammabiUty of the polystyrene pyrolysis products (36). 

Property AST M test ABS Noryl a Nylon b P< Polyeste d r HD PE Polypropyle ne High impact polystyrene Polyurethane PV C... 

Noryl is an alloy of poly(2,6-dimethyl-l,4-phenylene ethei) and polystyrene. 

Noryl. Noryl engineering thermoplastics are polymer blends formed by melt-blending DMPPO and HIPS or other polymers such as nylon with proprietary stabilizers, flame retardants, impact modifiers, and other additives (69). Because the mbber characteristics that are required for optimum performance in DMPPO—polystyrene blends are not the same as for polystyrene alone, most of the HIPS that is used in DMPPO blends is designed specifically for this use (70). Noryl is produced as sheet and for vacuum forming, but by far the greatest use is in pellets for injection mol ding. 

Noryl is a rigid dimensionally stable material. Dimensional stabiUty results from a combination of low mold shrinkage, low coefficient of thermal expansion (5.9 x 10 per° C), good creep resistance (0.6—0.8% in 300 h at 13.8 MPa (2000 psi)), and the lowest water absorption rate of any of the engineering thermoplastics (0.07% in 24 h at room temperature). Noryl resins are completely stable to hydrolysis. They are not affected by aqueous acids or bases and have good resistance to some organic solvents, but they are attacked by aromatic or chlorinated aUphatic compounds. 

DMPPO—polystyrene blends, because of the inherent flame resistance of the DMPPO component (oxygen index ca 29.5), can be made flame retardant without the use of halogenated additives that tend to lower impact strength and melt stabiUty in other polymers. Approximately one-half of total Noryl sales volume is in flame-retarded grades, ie, VO or VI in a 1.6-mm section (UL-94). 

General Electric is the only U.S. producer of Noryl resin and also has faciHties in Japan and Europe. DMPPO is also produced in Japan by Ashahi, Mitsubishi Gas Chemical, and Sumitomo. 

Health and Safety Factors. Animal-feeding studies of DMPPO itself have shown it to be nontoxic on ingestion. The solvents, catalyst, and monomers that are used to prepare the polymers, however, should be handled with caution. Eor example, for the preparation of DMPPO, the amines used as part of the catalyst are flammable toxic on ingestion, absorption, and inhalation and are also severe skin and respiratory irritants (see Amines). Toluene, a solvent for DMPPO, is not a highly toxic material in inhalation testing the TLV (71) is set at 375 mg/m, and the lowest toxic concentration is reported to be 100—200 ppm (72). Toxicity of 2,6-dimethylphenol is typical of alkylphenols (qv), eg, for mice, the acute dermal toxicity is LD q, 4000 mg/kg, whereas the acute oral toxicity is LD q, 980 mg/kg (73). The Noryl blends of DMPPO and polystyrene have PDA approval for reuse food apphcations. 

Property ASTM method Noryl SelOo " Prevex vqa Noryl GFN3""... 

Modified nylons are blends of nylon resins and specially grafted nylon resins. In the Du Pont family of Zytel resin, certain blends have been designated Supertough to emphasize the improvement in impact that blends provide over standard resins. General Electric s Noryl GTX resins consist of a nylon matrix resin and a PPO resin in dispersed form. A highly sophisticated blend, it maintains a filled nylon s HPT with no sacrifice of impact resistance. 

Blends of ABS with polycarbonates have been available for several years (e.g. Bayblend by Bayer and Cycoloy by Borg-Wamer). In many respects these polymers have properties intermediate to the parent plastics materials with heat distortion temperatures up to 130°C. They also show good impact strength, particularly at low temperatures. Self-extinguishing and flame retarding grades have been made available. The materials thus provide possible alternatives to modified poly(phenylene oxides) of the Noryl type described in Chapter 21. (See also sections 16.16 and 20.8.)... 

Unfortunately for PPO its price is too great to justify more them very restricted application and this led to the introduction of the related tmd cheaper Noryl materials in 1966 by the General Electric Corporation. These will be discussed in the next section. In recent years the only sources of unmodified PPO have been the USSR (Aryloxa) and Poland (Biapen). 

The processing of blends of an amorphous material (polystyrene) and a crystalline material with a high melting point (PPO) reflects the nature of the constituent materials. The processing is mainly by injection moulding, and the major points to be considered when processing Noryl-type materials are ... 

Polyamide PPOs are manufactured by General Electric (Noryl GTX), BASF having now withdrawn from marketing their product (Ultranyl). Usage of the blends has so far been mainly in the automobile field for such applications as valance panels, wheel trims, grilles, rear quarter panels, front bumpers and tailgates. 

Figure 32.1. Polar diagrams for three thermoplastic materials, CYCOLOY (a PC/ABS blend), ULTEM (polyetherimide) and NORYL (a styrenic PPO). The shaded area indicates the range...

These results demonstrate some interesting chemical principles of the use of acrylic adhesives. They stick to a broad range of substrates, with some notable exceptions. One of these is galvanized steel, a chemically active substrate which can interact with the adhesive and inhibit cure. Another is Noryl , a blend of polystyrene and polyphenylene oxide. It contains phenol groups that are known polymerization inhibitors. Highly non-polar substrates such as polyolefins and silicones are difficult to bond with any technology, but as we shall see, the initiator can play a big role in acrylic adhesion to polyolefins. 

Can handle special plating grades of ABS, PP, polysulfone, filled Noryl, filled polyesters, some nylons. 

In the present study DSC and TGA data were run on DuPont 910 and DuPont 951 instruments, respectively. Arapahoe Smoke Chamber results were obtained on a commercial apparatus. Coated samples used were commercially prepared zinc arc spray samples on Noryl FN 215 Structural Foam. 

Noryl GFN-3-70 polyphenylene oxide/polystyrene with fiberglas... 

Polyblends of impact-resistant polystyrene and PPO (NORYL, General Electric). ... 

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