Nylon polymerisation


The magnitude of the intellectual achievement of Carothers often overshadows the tremendous effort and success that followed in building the necessary industrial infrastmcture and developing the numerous scientific and engineering innovations required to make nylon a successhil commercial venture. One of the first of these was the development of a route to produce the starting materials from "coal, air, and water," and the first intermediates plant was built at Belle, West Virginia (10). Another was the invention of the autoclave polymerisation process using balanced salt and acetic acid end termination to control the molecular weight of the final polymer. Because nylon-6,6 was insoluble in all common solvents, a new melt-spinning process was required to form fibers and wind them onto packages. Also, the two-step drawing process was invented to develop the hill strength of the fibers. Additional inventions were required for effective downstream processing of this new synthetic fiber in order to dye and form it into finished goods. Finally, strong markets were required to support the financial investment necessary for this revolutionary product fortunately, nylon was extremely well suited to compete in the high value sHk markets.  [c.219]

Polymer Production. Three processes are used to produce nylon-6,6. Two of these start with nylon-6,6 salt, a combination of adipic acid and hexamethylenediamine in water they are the batch or autoclave process and the continuous polymerisation process. The third, the soHd-phase polymerisation process, starts with low molecular weight pellets usually made via the autoclave process, and continues to build the molecular weight of the polymer in a heated inert gas, the temperature of which never reaches the melting point of the polymer.  [c.233]

The polymerisation process proceeds in a manner similar to that of other type AABB polyamides, such as nylon-6,6. The final resin had found apphcation in automotive and other high performance end uses but was withdrawn from the market in 1994.  [c.236]

Fig. 4. Typical nylon-6,6 autoclave polymerisation cycle showing the changes in pressure (—) and temperature (---). To convert MPa to psi, multiply by Fig. 4. Typical nylon-6,6 autoclave polymerisation cycle showing the changes in pressure (—) and temperature (---). To convert MPa to psi, multiply by
Nylon-4,6. This nylon is produced from diaminobutane and adipic acid. The process is similar to that for nylon-6,6, but the amine has a high tendency to cyclize and the temperatures are therefore kept low. This results ia a low molecular weight polymer, which is subsequently iacreased ia viscosity by sohd-state polymerisation.  [c.272]

D. B. Jacobs and J. Zimmerman, in C. E. Schildknecht and I. Skeist, eds.. Polymerisation Processes, High Polymers, Vol. XXIX. Wiley-Interscience, New York, 1977, pp. 424, 467. A very detailed review of nylon-6,6 polymerization.  [c.277]

Large amounts of NMP are consumed in the polymer industry as a medium for polymerisation and as a solvent for finished polymers. Polymers that are soluble in NMP are poly(vinyl acetate), poly(vinyl duoride), polystyrene, nylon and aromatic polyamides and polyimides (qv), polyesters (qv), acryhcs, polycarbonates (qv), cellulose derivatives, and synthetic elastomers. l-Methyl-2-pyrrohdinone is also usefiil for cleaning and stripping of magnetic wire coatings and electronic parts as well as in agricultural appHcations for preparing emulsifiable concentrates. Its low toxicity has allowed it to displace chlorinated solvents in many of these appHcations as well as in paint and finish removers (qv), where it is gaining increasing popularity (91).  [c.363]

The early development of the nylons is largely due to the work of W. H. Carothers and his colleagues, who first synthesised nylon 66 in 1935 after extensive and classical researches into condensation polymerisation. Commercial production of this polymer for subsequent conversion into fibres was commenced by the Du Pont Company in December 1939. The first nylon mouldings were produced in 1941 but the polymer did not become well known in this form until about 1950.  [c.478]

The polymerisation casting of nylon 6 in situ in the mould has been developed in recent years. Anionic polymerisation is normally employed a typical system uses as a catalyst 0.1-1 mol.% of acetic caprolactam and 0.15-0.50 mol.% of the  [c.486]

Reaction injection moulding techniques, developed primarily for polyurethanes (see Chapter 27), have also been adapted for nylon 6 in what must be considered as a variation of the polymerisation casting technique.  [c.487]

It will be seen from this that a variety of atoms can be present along the carbon backbone and indeed carbon atoms may also be replaced, as in the cases of nylon and acetal. During polymerisation it is possible to direct the way in which monomers join on to a growing chain. This means that side groups (X) may be placed randomly (atactic) or symmetrically along one side of the chain (isotactic) or in regular alternating pattern along the chain (syndiotactic) as shown in Fig. A.7. A good example of this is polypropylene which in the atactic form is an amorphous material of little commercial value but in the isotactic form is an extremely versatile large tonnage plastic material.  [c.418]

Condensation polymerisation In this case reaction between two groups occurs which leads to the production of a polymer and also a simple molecule, e.g. reaction between adipic acid and hexamethylene diamine yields nylon 66 and water  [c.914]

The first patent for the production of synthetic polyamides was issued in 1937 to Wallace H. Carothers, who was working at Du Pont Company (5). His pioneering work in the development of polymeric materials led in a few years to the commercialisation of nylon-6,6 as the first synthetic fiber. In 1941 P. Schlack at 1. G. Farbenindustrie in Germany was issued a patent for nylon-6 based on the polymerisation of caprolactam [105-60-2] (6). Ironically, Carothers first attempt to synthesise polyamides in 1930 was to make nylon-6 from 6-aminohexanoic acid, but for unexplained reasons he was only able to produce a low molecular weight polymer (7). At this time he and his co-workers also made other polyamides from dibasic acids and aUphatic diamines (8) however, owing to their low solubiUty and high melting point, this work was also abandoned for the next five years while they worked on other polymers, including neoprene and polyesters. In July 1935, nylon-6,6 was chosen by Du Pont to be the specific polyamide for commercial introduction. This choice was based on its balance of physical properties making it suitable for fiber production and the potential for a low cost source of starting materials from six-member ring carbon compounds derived from coal (qv) (9). In less than one year, Du Pont scientists and engineers built the first commercial plant in Seaford, Delaware, which began production in 1939.  [c.219]

Nylon-6,9, Nylon-6,10, and Nylon-6,12. These related polyamides ate produced in a process similar to that used for nylon-6,6, where a salt of hexamethylenediamine and the appropriate diacid is formed in water. The solution is heated in an autoclave until polymerisation is complete. Processing times, pressures, and temperatures are adjusted for the slightly different melting points and viscosities of these polymers. Because of the lower melting points, ie, nylon-6,9 (T = 210° (7), nylon-6,10 (T = 220 (7), and nylon-6,12 (T = 212" (7), and the perhaps greater chemical stabihty of the diacids, these polymers generally experience less thermal degradation in processing than nylon-6,6. They ate generally used as engineering resins for specialty appHcations where reduced moisture regain and chemical resistance are important. Nylon-6,12 [24936-74-1] and its copolymers are also used in the manufacture of toothbmsh btisties and fishing line.  [c.236]

Nylon-6. This nylon is produced from caprolactam (qv) in the presence of water. The reaction is initiated by a hydrolytic ring opening to aminocaproic acid followed by reaction of the amine end with caprolactam [105-60-2] giving ring opening and further reaction. The polymerisation, which takes place at 240—280°C, can be carried out at atmospheric pressure a continuous process (the VK tube process) was developed as early as 1940 (15,16). Nylon-6 is almost always produced by continuous means in the 1990s. Figure 5 shows one such system, which involves three vessels for hydrolysis and polymerization the single VK tube for these operations is still also widely used. The equiUbrium with caprolactam estabUshed in the polymerization leaves about 10% unreacted monomer in the product. This needs to be removed for most plastics operations, unless plasticized material is required. The removal is normally done by water extraction followed by drying, although vacuum removal from the melt is also employed. The whole process is carried out under an inert gas such as nitrogen to avoid discoloration.  [c.271]

Copolymers. Copolymers from mixtures of different bisphenols or from mixtures of dichlorosulfone and dichiorohen ophenone have been reported in the patent Hterature. Bihmctional hydroxyl-terrninated polyethersulfone oligomers are prepared readily by the polyetherification reaction simply by providing a suitable excess of the bisphenol. Block copolymers are obtained by reaction of the oligomers with other polymers having end groups capable of reacting with the phenol. Multiblock copolymers of BPA-polysulfone with polysiloxane have been made in this way by reaction with dimethyl amino-terminated polydimethyl siloxane the products are effective impact modifiers for the polyethersulfone (79). Block copolymers with nylon-6 are obtained when chlorine-terminated oligomers, which are prepared by polyetherification with excess dihalosulfone, are used as initiators for polymerisation of caprolactam (80).  [c.332]


See pages that mention the term Nylon polymerisation : [c.144]    [c.307]   
Plastics materials (1999) -- [ c.486 ]