Nylons heat stabilizers

Acid-treated clay catalyst Engelhard F-24 was found to be very effective for the alkylation of diphenylamine (DPA) with an olefin such as a-methyl styrene (AMS) to obtain a mixture of mono and dialkylated diphenylamines (Chitnis and Sharma, 1995). For example, alkylation of DPA with AMS produced a mixture of 4-(a,a-dimethyl benzyl) diphenylamine, i.e. monocumyl-diphenylamine (MCDPA) and 4,4 -bis(a,a-dimethylbenzyl) diphenylamine, i.e. dicumyldiphenylamine (DCDPA) (Eqn.(l 1)). The dialkylated diphenylamine, i.e. DCDPA, is indu.strially important as an antioxidant and heat stabilizer. DCDPA is reported to be an ideal antioxidant for many materials like polyethylene, polypropylene, polyether polyol, polyacetals, nylon 6, synthetic lubricants, hot melt adhesives, etc. 

Along with nylons, polyester fibers approach and exceed common natural fibers such as cotton and wool in heat stability, wash-and-wear properties, and wrinkle resistance. Blended textiles from polyester, cotton, and wool also can be made to be permanent-press and... 

A number of plastics are condensation polymers and include polyesters and nylons that are not as highly oriented as the same materials but in fiber form. Other plastics have been developed that have outstanding heat stability, strength, and other properties that allow their wide use. These plastics include polycarbonates, polyimides, polybenzimidazoles, polysulfides, polyethers, polysulfones, and polyketones. 

A continuing trend has been to polymeric retainers. Laminated phenolic cages have often been used for high speeds at temperatures up to 130°C. Heat stabilized nylon-6,6 has come into broad use in small ball bearings, both with and without glass reinforcement (39). Polyimide and PTFE are used up to 250°C. 

Catalysts. Iodine and its compounds are very active catalysts for many reactions (133). The principal use is in the production of synthetic rubber via Ziegler-Natta catalysts systems. Also, iodine and certain iodides, eg, titanium tetraiodide [7720-834], are employed for producing stereospecific polymers, such as polybutadiene rubber (134) about 75% of the iodine consumed in catalysts is assumed to be used for polybutadiene and polyisoprene polymerization (66) (see Rubber CHEMICALS). Hydrogen iodide is used as a catalyst in the manufacture of acetic acid from methanol (66). A 99% yield as acetic acid has been reported. In the heat stabilization of nylon suitable for tire cordage, iodine is used in a system involving copper acetate or borate, and potassium iodide (66) (see Tire cords). 

Research into controlled-release antimicrobials continues with organo-silver compounds and silver zeolites, which are promising candidates for textile finishes. Silver ions, for example, incorporated in glass ceramic, have a very low toxicity profile and excellent heat stability. These principles are also used for fibre modification, an alternative to the antimicrobial finishes with high permanence. In recent years a variety of antimicrobial modified fibres have been developed, including polyester, nylon, polypropylene and acrylic types. An example of these fibre modifications is the incorporation of 0.5-2 % of organic nitro compounds... 

Monocast. [Polymer Corp.] Heat-stabilized nylon u in paper and textile, construction, mining, metalworking, and material handling industries for bearings, valve seats, seals, gears, wheels, guides, tooling fixtures, insulators, wear parts. 

Celanese Nylon. [Hoechst Celanese/ Engineering Plastics Hoechst UK] Nylon 6/6 resins, some glass-reinforced, heat-stabilized, lubricated for inj. molding and extrusion of mech. parts, gears, bearings, hardware, automotive parts, monofflaments. 

Heat stabilizers include copper salts, phosphoric acid esters, mercaptobenzothiazole, mercaptobenzi-midazole, and phenyl-fi-naphthyl-amine. Among light stabilizers are carbon black and various phenolic materials. Self-lubricating grades of nylon which are of value in some gear and bearing applications incorporate lubricants such as molybdenum disulfide (0.2%) and graphite (1%). 

Uses Plastics lubricant and processing aid pigment dispersant internal lubricant for PVC, nylon 6, nylon color cones. for adhesives, floor finishes, personal care, plastics, wax blends gellant for oils in personal care prods., pharmaceuticals film-former oil or fragrance encapsulator nonirritating abrasive emollient heat stabilizer food pkg. adhesives, coatings, paper/paperboard, cellophane, rubber articles, lubricants, textiles food-contact defoamer... 

Uses Heat stabilizer for PVC, ABS, polyolefins, elastomers, acrylics, adhesives, nylon, PC, PU, PS, coalings, PET food pkg. adhesives, coatings, nibber articles, polymers, closures with sealing gaskets for food containers... 

Chem. Descrip. Trisnonylphenyl phosphite CAS 26523-78-4 EINECS/ELINCS 247-759-6 Uses Processing stabilizer, heat stabilizer for polyolefins, acrylics, adhesives, elastomers, nylon, PC, PU, PS, PVC, coatings, ABS, and PET, food-contact pkg., m lcal devices, color-critical polyolefins, sfyrene block copolymers... 

Methods for meat species identification based on DNA analysis benefit from the heat stability of the DNA molecule and its high specificity. Originally, DNA methods consisted of immobilization of partially purified and denatured DNA, extracted from the meat product sample, on a nylon membrane, followed by hybridization of a species-specific segment of labeled (colorimetric, fluorescent, or chemiluminescent) DNA with any complementary sequences of DNA present on the membrane. More recently, a DNA amplification method - the polymerase chain reaction - has been used, but this is a relatively expensive and technically demanding technique. 

Figure 6.55 Stress vs. strain at various temperatures for conditioned EMS-Grivory Grilamid LV-3H—30% glass fiber, heat stabilized Nylon 11 resin [3].

Figure 6.62 PVT for Evonik Industries Vestamid LI 723 sw (DAM)—low viscosity, plasticized, heat stabilized Nylon 12 resin.

Figure 6.67 Shear modulus vs. temperature for DSM Engineering Plastics Stanyl TE250 Series—fiber glass filled, heat stabilized, fire retardant Nylon 46 resins [5].

Figure 6.152 Dielectric strength vs. moisture content and temperature for BASF Ultramid A3EG6—30% glass fiber, heat stabilized Nylon 66 resin [8].

Figure 6.187 Coefficient of thermal expansion vs. temperature according to ISO 11359 for Evonik Industries Vestamid DX9300—low viscosity, heat stabilized, with improved release properties Nylon 612 resin [9].

Figure 6.201 Stress vs. strain at various temperatures for EMS-Grivory Grilon TS VO—heat stabilized, flame retardant Nylon 6/66 resin (conditioned at 50% RH).

Quinacridone pigments are available in orange, red, and violet. They have good light fastness, excellent bleed and chemical resistance, and adequate heat stability for most plastics. However, they are high in cost. They perform best in polystyrene and acrylic at lower temperatures. They are not recommended for nylon. 

Nycast XHA, Heat-stabilized cast nylon. Cast Nylons Ltd. 

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