Noryl thermal

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. 

One can assume that blends of polymers will be more difficult to color than any single component by itself. Diffuse reflection can increase due to internal light reflection or scattering at phase interfaces if the polymers are at least partially immiscible or their refractive indices are significantly different. Blends of translucent polymers are typically more opaque than either resin alone. Furthermore, colorant stability (thermal or chemical) can be adversely affected by the presence of the other polymer(s). As in the case of neat polymers, both circumstances will result in a restricted achievable color gamut for the polymer blend. An example of a prominent polymer blend is GE s Noryl (PS/PPO), which certainly colors much differently than the polystyrene component by itself. 

Polyphenylene ether resins were developed in the early 60 s but could not be processed because the thermal degradation temperature was a few degrees below the melt temperature required for processing. Later discovery that PS can act as a plasticizer lead to the introduction of PPE/PS, one of the most successful blend (Noryl , Prevex , Luranyl ). 

Noryl, for example, is composed of polystyrene, an inexpensive polymer, and polyfphenylene oxide) or PPO, a relatively expensive polyether. For the most, the properties of Noryl are additive. For example, Noryl has poorer thermal stability than the polyether alone, but is easier to process. Its single glass transition temperature increases with increasing polyether content. In terms of tensile strength, however, the polyblend is synergistic. 

The products from the thermal degradation of Noryl GTX poly(phen-ylene oxide)-polyamide in air and in nitrogen have been identified and quantified. Ecotoxicologic testing of the products of pyrolysis with aquatic organisms indicated that in a fire, no greater harm than burned beech wood is to be expected when the fire-fighting water reaches aquatic ecosystems. ... 

Noryl, PPO rigid, tough, stable, thermal and chemical resistance tools and machinery, automotive... 

Other thermoplastic resins can be added to produce a polymer blend in order to achieve a desirable balance of mechanical/thermal properties and cost (e.g. PPO/PS, Noryl from GE). Most blends are two phase systems, where no stress transfer to the dispersed phase is possible. PPO/PS is a special case and forms a single blend Tg between the values of the PPO (210°C) and PS (100°C) depending on the relative proportion of the two polymers (e.g. about 150°C for Noryl). 

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. 

Noryl EF expandable beads, an interpoljnner of PPE and expandable polystyrene EPS, are available in 100, 200, and 300 series. FR grades use a nonbrominated, nonchlorinated flame retardant. The grades are bsted below along with an indication of their thermal stabihty, i.e., temperature at which there is no significant deformation after 1-h exposure (ISO 2796-1980). These grades and key features include... 

Noryl GTX 918W 372 = F (189°C) HDT at 66 psi (0.45 MPa) high flow grade for under-the-hood and electrical apphcations requiring retention of properties under thermal load... 

Skrypnyk,I.D. and J.L. Spoormaker, Prediction of Residual Deformation in clamped Noryl Gtx Plates after Thermal Cycles ANTEC 2001. 

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