Polyamides products

Amidation. Heating of the diammonium salt or reaction of the dimethyl ester with concentrated ammonium hydroxide gives adipamide [628-94-4] mp 228°C, which is relatively insoluble in cold water. Substituted amides are readily formed when amines are used. The most industrially significant reaction of adipic acid is its reaction with diamines, specifically 1,6-hexanediamine. A water-soluble polymeric salt is formed initially upon mixing solutions of the two materials then hea ting with removal of water produces the polyamide, nylon-6,6. This reaction has been studied extensively, and the hterature contains hundreds of references to it and to polyamide product properties (31). 

In 1973 Du Pont commenced production of another aromatic polytunide fibre, a poly-(p-phenyleneterephthalamide) marketed as Kevlar. It is produced by the fourth method of polyamide production listed in the introductory section of this chapter, namely the reaction of a diamine with a diacid chloride. Specifically, p-phenylenediamine is treated with terephthalyl chloride in a mixture of hexamethylphosphoramide and V-methylpyrrolidone (2 1) at -10°C Figure 18.32). 

For condensation polymerization, it is necessary to have two functional groups on each monomer and to mix stoichiometric amounts of the reactants. In polyamide production, the starting materials first form nylon salt by proton transfer ... 

The presence of even small amounts of cyclic oligomers can be detrimental for the utilization of a polymer if the cyclics migrate out of the product during its use. Many commercial processes remove cyclic by extraction (e.g., with steam in polyamide production) or thermal devolatilization (polysiloxane). 

National Emission Standards for Hazardous Air Pollutant Emissions Group I Polymers and Resins National Emission Standards for Hazardous Air Pollutants for Epoxy Resins Production and Non-Nylon Polyamides Production National Emission Standards for Hazardous Air Pollutants From Secondary Lead Smelting National Emission Standards for Marine Tank Vessel Tank Loading Operations National Emission Standards for Hazardous Air Pollutants From Phosphoric Acid Manufacturing... 

Pollutants for Epoxy Resins Production and Non-Nylon Polyamides Production... 

Although the product of this early technology was a molten polymer, the rapid polymerization and high molecular weight polyamide product are clearly desirable qualities for a reaction injection molding (RIM) system. 

Copyright certificate No 235160 of Czechoslovakia. Dyeing of polyamide products in mass into yello v (1987) (in Russian). 

Dimethyl adipate (43.55 g, 0.25 mol), diethylene triamine (28.33 g, 0.275 mol) and 2.5 g of Novosjym 435 (immobilized Candida antarctica lipase) were mixed in a 250-ml flask and heated in an oil bath to 90°C. The viscous mixture was stirred at 90°C for 16 hrs in an open vessel with a steam of nitrogen. The product turned into a yellowish solid at the end of the reaction. 150 ml of methanol was added to dissolve the polyamide product. The immobilized enzyme was insoluble in the methanol solution and was removed by filtration. Methanol was removed by evaporating using a rotary evaporator under a reduced pressure to give the product as a yellowish solid. The yield was 48 g M 8,400 M /M 2.73. 

Linear aliphatic homopolyamides are partially crystalline materials. Therefore they are characterized by both an unordered amorphous state and an ordered crystalline state. The latter may exhibit polymorphism. The extent to which each state or specific modification is represented depends, for a given chemical structure, considerably on processing conditions and treatment operations. It affects the properties of the shaped polyamide product. Thus the corresponding structure parameters are of importance for optimizing fiber processes as well as for assessing the performance of fiber products in particular applications. 

Table 4 Structure of aromatic polyamides (product names, e.g., Aramide) [4]...

Polymers Resins II Epoxy Resins Production, Non-Nylon Polyamides Production 03/03/98... 

The synthesis of polyamides of the nylon series has the advantage that the fraction of monomers and oligomers at the polycondensation equilibrium is very small. Consequently monomers and oligomers do not have to be removed from the polyamide, which is in contrast to polyamide production by lactam polymerization. On the other hand, the nylon polycondensation is not as straight-forward a process as the lactam polymerization. For historical reasons, PA 6,6 dominates the market in England and the USA, whereas in West Germany and Japan, PA 6 plays the dominant role. 

Of all the polyamides, nylon 6 and nylon 6,6 are produced in by far the greatest quantity. In the United States, about 78% of the polyamide production is nylon 6,6, while in Germany, about 65% is nylon 6. This development can be explained on historical grounds Nylon 6,6 was first manufactured in the United States (du Pont), while in Germany the first commercial polyamide was Perlon (nylon 6 IG Farben). In the United States in 1964, 32% of the nylon production was used for tire cord, 22% for carpets, and 17% for outerwear clothing. 

The reaction of 4-phenyl-3-buten-4-olide with benzylamine was investigated as a model for polyamide synthesis. Linear polyamides were prepared from ringopening polyaddition of 4,4 -disubstituted bis(3-buten-4-olide) in m-cresol u g aliphatic diamines. Further studies have investigated the production of hydroxy-substituted polyamides from 4,4 -disubstituted bis(4-butanoiide) and polyamide production from 2,2 -p-phenylene bis-oxazolones by similar ring opening reactions with diamines. ... 

BAT is to treat flue-gases from polyamide production processes by wet scrubbing. 

Improves Impact strength of recycled polyamide products. General Properties ... 

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