Polymer polycaprolactam

Nylon, an aliphatic polyamide, was introduced as a commercial tire cord in 1947 and grew in usage to 5.4 billion kg/yr ( 2 billion lb/yr) in the 1990s (10,11). Nylon-reinforced tires use nylon-6 polymer (polycaprolactam) fibers as well as nylon-6,6 (poly(hexamethylenediamine adipamide)) fibers. Nylon tire cords are characterized by extremely good fatigue resistance in compression and good adhesion to most mbber compounds with simple RFL adhesives. 

The molecular weights obtained by this method are averages. This is particularly evident from the situations where additives are present. In these cases, two different kinds of chains result, with those terminated by the same end group being stunted in growth compared to the normal polycaprolactam. Yet it is the total weight of polymer and the total number of ends that are... 

The more familiar source-based names for these polymers are poly(phenylene oxide) (1), poly(ethylene terephthalate) (2), and polycaprolactam (3). 

An MAI composed of polycaprolactam was investigated on its thermal decomposition behavior to develop easy decomposable polymers, the addition of oxidative deterioration was needed [72]. 

In semi-cristalline polymers, rate-enhancement under stress has been frequently observed, e.g. in UV-photooxidation of Kapron, natural silk [80], polycaprolactam and polyethylene terephthalate [81]. Quantitative interpretation is, however, difficult in these systems although the overall rate is determined by the level of applied stress, other stress-dependent factors like the rate of oxygen diffusion or change in polymer morphology could occur concurrently and supersede the elementary molecular steps [82, 83], Similar experiments in the fluid state showed unequivocally that flow-induced stresses can accelerate several types of reactions, the best studied being the hydrolysis of DNA [84] and of polyacrylamide [85]. In these examples, hydrolysis involves breaking of the ester O —PO and the amide N —CO bonds. The tensile stress stretches the chain, and therefore, facilitates the... 

CL must be very carefully purified to exclude small concentrations of (1) ferric ions which would catalyze die thermal oxidative degradation of polycaprolactam and (2) aldehydes and ketones which would markedly increase oxidizability of CL. The impurities in CL may retard die rate of CL polymerization as well as having a harmful effect on die properties of die polymer fiber. In die vacuum depolymerization of nylon-6, a catalyst must be used because in die absence of a catalyst by-products such as cyclic olefins and nitrides may form, which affects the quality of die CL obtained.1... 

The other entries in Table 13.2 show that heat removal is not a problem for most ring-opening and condensation polymerizations. Polycaprolactam (also called Nylon 6) is an addition polymer, but with rather similar bond energies for the monomer and the polymer. The reaction exotherm is small enough that large parts are made by essentially adiabatic reaction in a mold. An equilibrium between monomer and polymer does exist for polycaprolactam, but it occurs at commercially acceptable molecular weights. 

Monomers may be in the solid, liquid or gaseous state. In the first phase, blending and comminution is generally carried out to reduce inhomogeneities. For the same reason, polymer particle size can also influence the reaction. For example, in the grafting of vinyl chloride on polycaprolactam, the Cl content of the resultant polymer was 3.71 % and 2.16% when 0.05-0.09 mm and 0.4-0.63 mm diameter polycaprolactam particles were employed (31). To obtain polymer in the desired powder form, the polymer was pulverized and selectively precipitated. 

Grohn and Vasiliu-Oprea (18,31,32,41) studied the grafting of several vinyl monomers on polyamide, mainly polycaprolactam. [Their work was summarized in the Simionescu and Vasiliu-Oprea book (73).] In each case, the polymer was first purified by extraction, dissolution and reprecipitation. The grinding was performed at 0.42 fraction packing and by using 16 mm diameter steel balls, at an amplitude of 1.75 mm and at 1420 rpm. With vinyl chloride the air was eliminated from the reaction jar and the monomer was introduced at up to two... 

The ring opening polymerization of cyclic monomers that yield thermoplastic polymers of interest in composite processing is reviewed. In addition, the chemistry, kinetics, and rheology of the ring opening polymerization of caprolactam to nylon 6 are presented. Finally, the rheo-kinetics modelsfor polycaprolactam are applied to the composite process of reaction injection pultrusion. 

EXAMPLE 4.5 Empirical Determination of the Mark-Houwink Coefficients for a Polymer Solution. The molecular weights of various polycaprolactam preparations were determined by end-group analysis (see Example 3.2) intrinsic viscosities of the various fractions in m-cresol were measured at 25°C. The following values are representative of the results obtained (Reim-schussel and Dege 1971) ... 

Instead of monomers, polymers in solution can be grafted on Nylon structures. Aqueous solution of poly(acrylic add) is used for impregnation of polyamide fabrics which is subsequently dried during 1 to 5hrs at 80-150° C after which cure is carried out for 15 to 60 min at 150-218° C (99). A copolymer of styrene-maleic anhydride is said to be grafted on polycaprolactam by heating at 230° C at a pressure of 25 kg/cm2 (100). 

Other polymers like polypropylene or polystyrene modified by maleic anhydride or maleamide, with the add groups converted to amide, ester or ester chloride and then reacted on Nylon fibers, have been claimed in a Japanese patent (101). Two patents report grafting of olefinic polymers on polycaprolactam (102,103). Grafting of polysiloxanes on polyamides can be induced by X-rays (104). 

Fig. 4. Change of viscosity of polycaprolactam heated at 250° initial polymer prepared with 0,06 mol-% NaCL + 0,10mol-% AcCL (3), extracted with 1% aq. acetic acid, followed by extraction with water (2), extraction with water (7)...

Platinum complexes, 161 Polarographic studies, 153, 154 of 2-aminothiazoles, 29 of 2-anilinothiazoles, 30 of 2-azothiazoles, 107, 108 Polyacrylonitrile, 105, 163, 164, 167 Polyamines, 156-168 Polycaprolactam, 156-168 Polyesters, 163, 165, 166, 167 Polyhalogenothiazole. reactivity of, 408-409 Polymers, e-caprolactam, butadiene, 438 Polymorphism, of sulfathiazole, 116 Positive colored image, 440 Postemergence activity, 134 Potassium salts, of acetamido thiazoles, 90 Potentiometric measurements, and amido-imido equilibrium, 116 and amino-imino equilibrium, 21 P.P.P. approximation, charge diagrams calculations by, 17... 

Note also that nylon-6 was listed in Table 2-2 as the product of the ringopening polymerization of the cyclic monomer caprolactam. So here is an example of the same polymer that can be made from (at least) two different monomers by two different mechanisms. This illustrates the complexity of our classification and nomenclature schemes, because polycaprolactam,... 

The absorption was correlated to the octanol-water partition coefficients of the drugs, suggesting that prediction of absorption from partition data is possible [30, 31]. Polymers such as Nylon-6 (polycaprolactam) are known to adsorb drug substances such as benzocaine [32],... 

Figure 5.1. Molecular structures of the chemical repeat units for common polymers. Shown are (a) polyethylene (PE), (b) poly(vinyl chloride) (PVC), (c) polytetrafluoroethylene (PTFE), (d) polypropylene (PP), (e) polyisobutylene (PIB), (f) polybutadiene (PBD), (g) c/5-polyisoprene (natural rubber), (h) traw5-polychloroprene (Neoprene rubber), (i) polystyrene (PS), (j) poly(vinyl acetate) (PVAc), (k) poly(methyl methacrylate) (PMMA), ( ) polycaprolactam (polyamide - nylon 6), (m) nylon 6,6, (n) poly(ethylene teraphthalate), (o) poly(dimethyl siloxane) (PDMS).

The same name would ordinarily be used even if the polymer were synthesized from ethylene glycol (HOCH2CH2OH), ethylene chlorohydrin (CICH2CH2OH), or bischloromethyl ether (CICH2OCH2CI). Similarly, structure 1-13 is called polycaprolactam because it is made industrially from the lactam by reaction (1-5), in preference to polymerization of the parent amino acid, H2N (CH2).[Pg.29]

There is also an alternative numbering system for synthetic polyamides. Polymers that could be made from amino acids are called nylon-.r, where x is the number of carbon atoms in the repeating unit. Thus, polycaprolactam (1-13) is nylon-6, while the polymer from m-aminoundecanoic acid is nylon-11. Nylons from diamines and dibasic acids are designated by two numbers, in which the first represents the number of carbons in the diamine chain and the second the number of carbons in the dibasic acid. Structure 1-6 is thus nylon-6,6. Nylon-6,6 and nylon-6 differ in repeating unit length and symmetry and their physical properties are not identical. 

Under a variety of conditions, COClj and polycaprolactam gave insoluble chlorine-containing polymers [1392],... 

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