Polymers polycaproamide

The hybrid nanocomposite polymer-silica materials on the basis of oligomer alkoxysilane (polyethoxysilane (PES) obtained from tetraethoxysilane) with polycaproamide, polyacrylonitrile, chitosan and zirconyl oxychloride were investigated. 

Modelling non-isothermal crystallization is the next important step in a quantitative description of reactive processing. This is particularly important, because crystallization determines the properties of the end product. Therefore, the development the spatial distribution of crystallinity, a, and temperature, T, with time throughout the volume of the reactive medium must be calculated. It is also noteworthy that crystallization and polymerization processes may occur simultaneously. This happens when polymerization proceeds at temperatures below the melting point of the newly formed polymer. A typical example of this phenomenon is anionic-activated polymerization of e-caprolactam, which takes place below the melting temperature of polycaproamide. 

Reactive extruders and extrusion dies of different designs can be easily included in standard technological scheme of polymer production plants, such as those for polycaproamide synthesis, as shown in Fig. 4.39. In this case, a reactive material premixed in a tank 1 is fed into a static device 2 for prepolymerization, where part of the polymerization process takes place. Then the reactive mixture enters the extruder-reactor 3. The necessary temperature distribution is maintained along the extruder. Transfer of the reactive mass proceeds by a system of two coaxial screws mounted in series in a common barrel. Controlling the relative rotation speed of both screws provides the necessary residence time for the reactive mass in the extrader, so that the material reaching the outlet section of the die is a finished polymer. 

Melting behaviour and spherulitic crystallization of polycaproamid (nylon 6). Polymer 3, 43—51 (1962). 

A few cases of prevailing polycondensation. Rec. Trav. Chim. 7,277 (1952). Macchi, E. M., N. MorGsoff, and H. Morawetz Polymerization in the solid state. X. The solid state conversion of 6-aminocaproic acid into oriented nylon 6. J. Polymer Sci., to be publi ed — Morosoff, N., D. Lim, and H. Morawetz Preparation of biaxially oriented polycaproamide by the solid state polycondensation of e-aminocaproic acid. J. Am. Chem. Soc. 86, 3167 (1964). 

Although there are clear lUPAC rules for naming the polymers, in practice various names for the same polymer are frequently encountered. As an example, a simple polymer such as nylon 6 (commercial name) can be named poly(e-caprolactam), poly[imino(1-0X0-1,6-hexandiyl)], poly(6-aminohexanoic acid), polycaproamide or poly(pentamethylenecarbonamide). 

Majority of dispersed dyes, used for PETP dyeing, are instable themselves [284, 286]. That is why it may be supposed that increase of dye concentration leads to accumulation of being formed radicals in the thin surface layer of the sample without mixing, as a result of which the rate of chain break rises and suppresses chain photooxidation of polymer. This effect was called by the authors [175] effect of concentration inhibition, which was observed in the case of polycaproamide light stabilization by action dyes. 

The objects of our investigations were four kinds of elastomers, of different structure and polarity, viz. cis-1,4-polybutadiene (BR)> butadiene-acrylonitrile copolymer (NBR), isobutylene-isoprene copolymers (IIR) and ethylene-propylene-diene terpolymer (EPT). They were mixed with plastomers low density polyethylene (PE] ), polystyrene (PS), polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC), polycaproamide (PCA) and polyacrylonitrile (PAN) (Table 1). The concentration of the plastomers in the mixtures was changed in the range from 0 to 50 pph of the elastomer. The polymers were blended at temperature T = 423 K by means of the micromill of the Plasti--Corder apparatus. After 24 hours, crosslinking substances, dicurayl peroxide (DCP) or sulphur and diphenylguanidine (S, DPG), were added at room temperature. The composition of the mixtures is given in Table 2. 

Reprinted by permission of John Wiley Sons, Inc. from Holmes, D. R., Bunn, C. W. and Smith, D. J. The crystal structure of polycaproamide nylon 6 , J. Polymer Sci. 17, 159 (1955). Copyright 1955 John Wiley Sons, Inc. 

The effect of the sohd body surface on the structure of the polymer boimdary layers has been considered in detail in a great number of pubhcations and we wiU not consider this issue in detail. We point out only that a number of pubhcations have reported correlation between the structure of the boimdary layer and the adhesion strength for couples such as metal—polycaproamide coating [33], fluoroplastic— steel [34], and epoxy rubber polymers-metals [35]. 

The only case of textile dermatitis reported to be caused by fiber polymers during the 1990s was that described by Tanaka et al. (1993). In this case, the specific nylon polymer was epsilon-aminocaprioic acid (EACA). This is not one of the usual polymers used to form nylon those polymers being polyhexamethylene adipamide for nylon 66 fibers and polycaproamide for nylon 6 fibers. 

Fig. 105. Dependence of the amount of 6 -caprolactam formed in the process of thermal depolymerization of polycaproamide in the presence of O.O370/0 water, on the duration of heating at 230 C for four samples with initial specific viscosity of the polymer 0.400 (1), 0.450 (2), 0.612 (3), and 0.786 (4).

For polycaproamide, the formation of cross-linked structures occurs more slowly at 280°C the polymer is converted to an infusible, insoluble product after 12 days. The authors explain the cross-linking of polyamides by the presence of secondary amino groups, formed in the interaction of the terminal amino groups, as was indicated above, as well as ketone groups, formed according to the following reaction (interaction of carboxyl groups) ... 

The mixed polyamide (anid G-669) is converted to a three-dimensional product at this same temperature. Such a behavior of polycaproamide is apparently explained by the fact that at high temperatures destruction of the caprolactam polymer predominates over thermal and thermooxidative structuring (at comparatively low temperatures - below 200°C —capron is structured at an even greater rate than anid G-669). 

Alfonso, G.C. Costa, G. Pasolini, M. Russo, S. Ballistreri, A. Montaudo, G. Puglisi, C. Flame-resistant polycaproamide by anionic pol3merization of e-caprolactam in the presence of suitable flame-retardant agents. 7. Appl. Polym. Sci. 1986, 31, 1373-1382. 

Similarly, thermal history may also affect fatigue life. This is shown in Fig. 3.23 which shows the difference heat treatment makes on the fatigue life of polycaproamide. In this case the upper curve has been heat treated for 1 h at 180°C in oil. The oil keeps oxygen away from the heated polymer. Had... 

Fig. 9.1. Generalized concentration dependence of the viscosity of solutions of polymers (the different points correspond to different polymers, where the most flexible-chain polymer is polycaproamide and the most rigid-chain polymer is poly-p-benzamide).

Aderno, D., Bianchi, E., Ciferri, A., Tealdi, A., Torre, R. and Valenti, B. (1976), Bulk properties of synthetic polymer-inorganic salt systems. 3. Flow behavior and glass-transition of salted polycaproamide. Journal of Polymer Science Part C-Polymer Symposium. (54) pp. 259-269. 

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