The Noryl family of modified resins consists of amorphous blends of polyphenylene oxides (PPO) or polyphenylene ether (PPE) resins with

polystyrene Polystyrene (PS) is a synthetic polymer made from monomers of the aromatic hydrocarbon styrene. Polystyrene can be solid or foamed. General-purpose polystyrene is clear, hard, and brittle. It is an inexpensive resin per unit weight. It i ...

. They combine the inherent benefits of PPE resin (affordable high heat resistance, good

electrical insulation Electricity is the set of physical phenomena associated with the presence and motion of matter possessing an electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by ...

properties, excellent

hydrolytic Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysis ...

stability and the ability to use non-halogen

fire retardant A fire retardant is a substance that is used to slow down or stop the spread of fire or reduce its intensity. This is commonly accomplished by chemical reactions that reduce the flammability of fuels or delay their combustion. Fire retardants ...

packages), with excellent dimensional stability, good processability and low

density Density (volumetric mass density or specific mass) is the ratio of a substance's mass to its volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' (or ''d'') can also be u ...

. They were originally developed in 1966 by

General Electric General Electric Company (GE) was an American Multinational corporation, multinational Conglomerate (company), conglomerate founded in 1892, incorporated in the New York (state), state of New York and headquartered in Boston. Over the year ...

Plastics (now owned by

SABIC Saudi Basic Industries Corporation (), known as SABIC (), is a Saudi chemical manufacturing company. 70% of SABIC's shares are owned by Saudi Aramco. It is active in petrochemicals, chemicals, industrial polymers and fertilizers. It is the second ...

). NORYL is a registered trademark of SABIC Innovative Plastics IP B.V. Noryl resins are a rare example of a homogeneous mixture of two polymers. Most polymers are incompatible with one another, so tend to produce separate phases when mixed. The two polymers compatibility in Noryl resins is due to the presence of a

benzene ring Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar hexagonal ring with one hydrogen atom attached to each. Because it contains only carbon and hydr ...

in the

repeat unit A repeat unit or repeating unit , or mer, is a part of a polymer whose repetition would produce the complete polymer chain (except for the end groups) by linking the repeat units together successively along the chain, like the beads of a necklace ...

s of both chains.

Properties

The addition of polystyrene to PPE increases the

glass transition temperature The glass–liquid transition, or glass transition, is the gradual and reversible transition in amorphous materials (or in amorphous regions within semicrystalline materials) from a hard and relatively brittle "glassy" state into a viscous or rub ...

above , owing to the high T_g of PPE, so Noryl resin is stable in boiling water. The precise value of the transition depends on the exact composition of the grade used. There is a smooth linear relation between weight content of polystyrene and the T_g of the blend. Due to its good electrical resistance, it is widely used in switch boxes. However, product design is important in maximising the strength of the product, especially in eliminating sharp corners and other

stress concentration In solid mechanics, a stress concentration (also called a stress raiser or a stress riser or notch sensitivity) is a location in an object where the stress (mechanics), stress is significantly greater than the surrounding region. Stress concentra ...

s. Injection molding must ensure that moldings are stress-free. Like most other amorphous thermoplastics, Noryl is sensitive to

environmental stress cracking Environmental Stress Cracking (ESC) is one of the most common causes of unexpected brittle failure of thermoplastic (especially amorphous) polymers known at present. According to ASTM D883, stress cracking is defined as "an external or intern ...

when in contact with many organic liquids. Compounds such as

gasoline Gasoline ( North American English) or petrol ( Commonwealth English) is a petrochemical product characterized as a transparent, yellowish, and flammable liquid normally used as a fuel for spark-ignited internal combustion engines. When for ...

kerosene Kerosene, or paraffin, is a combustibility, combustible hydrocarbon liquid which is derived from petroleum. It is widely used as a fuel in Aviation fuel, aviation as well as households. Its name derives from the Greek (''kērós'') meaning " ...

, and

methylene chloride Dichloromethane (DCM, methylene chloride, or methylene bichloride) is an organochlorine compound with the formula . This colorless, volatile liquid with a chloroform-like, sweet odor is widely used as a solvent. Although it is not miscible with ...

may initiate brittle cracks resulting in product failure.

Applications

Noryl resins offer a good balance of mechanical and chemical properties, and may be suitable for a wide variety of applications such as in electronics, electrical equipment, coating, machinery, etc. One of the most famous applications of Noryl was the molded case of the original

Apple II Apple II ("apple Roman numerals, two", stylized as Apple ][) is a series of microcomputers manufactured by Apple Computer, Inc. from 1977 to 1993. The Apple II (original), original Apple II model, which gave the series its name, was designed ...

computer. At that point, the product was referred to internally at Apple (1978) as "GE NORYL". A famous picture of an Apple II was made after a fire almost completely melted the Noryl case, but the motherboard, when removed from the case, was found to still operate. Noryl resins have possible applications in the production of hydrogen, where it could serve as cost-effective electrodes in an electrolyzer, replacing expensive rare elements. It is highly resistant against the alkaline potassium hydroxide. For conductivity, the plastic is sprayed with a nickel-based catalyst.Technology Review: Hydrogen on the Cheap
/ref> Noryl resins are being investigated as a possible replacement for

polycarbonate Polycarbonates (PC) are a group of thermoplastic polymers containing carbonate ester, carbonate groups in their chemical structures. Polycarbonates used in engineering are strong, toughness, tough materials, and some grades are optically transp ...

used in the manufacturing of

Blu-ray Blu-ray (Blu-ray Disc or BD) is a digital optical disc data storage format designed to supersede the DVD format. It was invented and developed in 2005 and released worldwide on June 20, 2006, capable of storing several hours of high-defin ...

Discs.Sabic Develops New Blu-ray Materials
/ref> It is also used in certain construction products, like water pumps for swimming pools.

References

External links

MIT Technology Review
- ''Hydrogen on the Cheap'' * {{cite web , url = http://tmsearch.uspto.gov/bin/showfield?f=doc&state=4807:parjp0.2.3 , title = USPTO registration of NORYL Polymers Polyethers SABIC

Properties

Applications

See also

References

External links