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, aromatic hydrocarbon styrene. Polystyrene can be solid or foamed. General-purpose polystyrene is clear, hard, and brittle. It is an inexpensive resin pe ...

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

electrical insulation An electrical insulator is a material in which electric current does not flow freely. The atoms of the insulator have tightly bound electrons which cannot readily move. Other materials—semiconductors and conductors—conduct electric current ...

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 i ...

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 substance's mass per unit of volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' can also be used. Mathematicall ...

. They were originally developed in 1966 by

General Electric General Electric Company (GE) is an American multinational conglomerate founded in 1892, and incorporated in New York state and headquartered in Boston. The company operated in sectors including healthcare, aviation, power, renewable ene ...

Plastics (now owned by

SABIC Saudi Basic Industries Corporation ( ar, الشركة السعودية للصناعات الأساسية), known as SABIC ( ar, سابك), is a Saudi chemical manufacturing company. 70% of SABIC's shares are owned by Saudi Aramco. It is active in ...

). 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 in the repeat units 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 ru ...

above 100 °C, 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) is a location in an object where the stress is significantly greater than the surrounding region. Stress concentrations occur when there are irregularit ...

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 inter ...

when in contact with many organic liquids. Compounds such as

gasoline Gasoline (; ) or petrol (; ) (see ) is a transparent, petroleum-derived flammable liquid that is used primarily as a fuel in most spark-ignited internal combustion engines (also known as petrol engines). It consists mostly of organic c ...

kerosene Kerosene, paraffin, or lamp oil is a combustible hydrocarbon liquid which is derived from petroleum. It is widely used as a fuel in aviation as well as households. Its name derives from el, κηρός (''keros'') meaning " wax", and was re ...

, and

methylene chloride Dichloromethane (DCM or methylene chloride, methylene bichloride) is an organochlorine compound with the formula . This colorless, volatile liquid with a chloroform-like, sweet odour 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 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 Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-to ...

, where it could serve as cost-effective

electrode An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor, an electrolyte, a vacuum or air). Electrodes are essential parts of batteries that can consist of a variety of materials ...

s in an

electrolyzer In chemistry and manufacturing, electrolysis is a technique that uses direct electric current (DC) to drive an otherwise non-spontaneous chemical reaction. Electrolysis is commercially important as a stage in the separation of elements from na ...

, replacing expensive rare elements. It is highly resistant against the

alkaline In chemistry, an alkali (; from ar, القلوي, al-qaly, lit=ashes of the saltwort) is a basic, ionic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a ...

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 groups in their chemical structures. Polycarbonates used in engineering are strong, tough materials, and some grades are optically transparent. They are easily work ...

used in the manufacturing of

Blu-ray The Blu-ray Disc (BD), often known simply as Blu-ray, is a digital optical disc data storage format. It was invented and developed in 2005 and released on June 20, 2006 worldwide. It is designed to supersede the DVD format, and capable of st ...

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