Polycaproamide Fibres Research Articles

Some features of the heterophase emulsion graft polymerization of glycidyl methacrylate to polycaproamide fibre

-- The special features of the graft polymerization of glycidyl methacrylate to polycaproamide fibre have been discovered. An anomalous effect of the copper compound and of hydrogen peroxide in the composition of the redox system on the rate of graft polymerization of glycidyl methacrylate has been found.

Thermooxidative decomposition of phosphorus and metal-containing polyamide fibres

-- The thermooxidative decomposition of phosphorus and metal containing polycaproamide fibres prepared by introducing combustion retarders into the polymer melt has been studied.

Preparation of cation-exchange polycaproamide fibers

-- The process of preparing cation-exchange PCA fibers by the radical graft polymerization of potassium p-styrene-sulfonate in aqueous and in aqueous salt solutions of the monomer has been investigated. The identity of the kinetic parameters (reaction order with respect to monomer and the effective activation energy) of the heterophase graft polymerization of PSS indicates the occurrence of the graft polymerization in the kinetic region.

Structure–property relationship of modified polypropylene–polycaproamide fiber

AbstractThe effect of the addition of polyamide on the structure and properties of polypropylene fiber has been studied. Although a good fiber is obtained with a composition containing only a very low concentration of polycaproamide in polypropylene, the increase in polyamide content decreases the drawing strength of the mixed polymer melt due to sudden lowering of melt viscosity and strength. The poor melt strength of the studied polymer mixture is attributed to increased heterogeneity induced in the system with increased concentration of polyamide. Use of an effective interphase modifier, maleic anhydride‐grafted polypropylene, however, was found to improve fiber properties of the studied polymer mixtures even with a very high concentration of polyamide as the dispersed phase. Thus, addition of a 1–4 wt % interphase modifier facilitates the formation of good fiber even with 30 wt % polycaproamide in the blend. This improvement is attributed to the improved dispersity of polyamide in the polypropylene matrix as well as improved phase compatibility due to the formation of a chemically modified polyamide during melt extrusion in the presence of maleic anhydride‐grafted polypropylene.

Modified polycaproamide fibres with improved heat resistance

The high efficiency of the method of grafting functionally active polymer to fibres from aliphatic polyamides to increase their thermal and chemical resistance has been demonstrated. When the easily oxidized PDMAEM, quaternary ammonium or pyridinium bases, especially in the presence of an epoxy group in the N-alkyl radical, is contained in the grafted chains, the increase in thermal resistance and chemical stability is caused by an effect of thermooxidative cross-linking of the polymer, accompanied by a loss in its thermal plasticity.

Studies of structure formation in grafting of polyacrylonitrile to polycaproamide fibers

AbstractThe relationship between the basic structure parameters of a polycaproamide (PCA) substrate and the structure of grafted polyacrylonitrile (PAN) was studied. The influence of the total degree of crystallinity of the PCA fiber, its crystal modification, and the orientation of crystallites on the PAN structure in the copolymer were analyzed. The structure of PCA‐PAN graft copolymers was studied by infrared spectroscopy (dichroism and ATR), X‐ray structure analysis, nuclear magnetic resonance, and scanning electron microscopy. The development of an oriented isotactic structure was found in PAN grafted to a PCA substrate having a bigh degree of orientation. The type of crystal modification of PCA does not affect the structure formation process in PAN. The oriented structures in PAN arise directly in the course of synthesis rather than on the subsequent rearrangement of the molecular chains under the action of orientation drawing. In contrast to earlier findings, our studies indicate that synthesis under the conditions specified increases the degree of crystallinity of PCA and crystallite size. The grafted PAN chains are presumed to grow epitaxially under the influence of PCA crystallites.

Effect of a glow discharge on the formation of a surface layer on polycaproamide fibres in the presence of an organophosphorus compound

The interaction of a glow discharge with polycaproamide fibres which have been impregnated with an involatile, unreactive liquid has been investigated.

Dyeing polycaproamide fibre in bulk

The advisability of using bis-aroylenebenzimidazole derivatives for dyeing fibres of PCA in bulk has been shown.

Stabilization of the elastic modulus of oriented polycaproamide fibres in a humid atmosphere

In oriented polycaproamide fibres, moisture absorption mostly occurs in amorphous domains of the polymer. The considerable increase in crystallinity (from 43 to 75%) of polycaproamide fibres after annealing under high pressure leads to an increase in the elastic modulus of the original dry fibre from 7·1 to 15·3 GPa. The annealed fibre exhibits lower moisture absorption (1·8%) and a higher elastic modulus in a humid atmosphere (8·0 GPa) as compared to the original unannealed fibre (7% and 1·2 GPa, respectively).

Porometric and electron-microscope investigation of polycaproamide fibres treated with a glow discharge

Morphological changes in polycaproamide fibre which take place on contact with high-frequency glow discharges have been studied.

Polycaproamide fibres with reduced combustibility

The basic characteristics of the composition of polycaproamide fibres in the presence of various phosphorus-containing compounds, introduced into the polymer melt before spinning, have been investigated.

Aspects of the structure of grafted polycrylonitrile on liquid-phase graft polymerization to polycaproamide fibres

The relationship between the main parameters of the structure of polycaproamide (PCA) fibre and the structure of grafted PAN has been investigated by IR spectroscopy and X-ray structural analysis. The influence of the orientation of the PCA crystallites, the type of their crystalline modification and the total degree of crystallinity on the structure of PAN in the copolymer has been studied. Graft polymerization with the method of initiation used increases the degree of crystallinity and the size of the PCA crystallites. The orientation of these crystallites after garfting increases. It is shown that the process of structuring of PAN does not depend on the type of crystalline modification of PCA. Oriented PAN crystallites appear directly in the course of polymerization of acrylonitrile on the PCA fibre and their advent is determined by the matrix influence of the PCA crystallites.

Preparation of fire-resistant polycaproamide fibres

A method had been developed for the preparation of fire-resistant polycaproamide fibres; it uses a three-component synergistic system of combustion retarders: boric acid + brominated pentaerythritol + antimony oxide. The effect of the synergistic system of combustion retarders is supported by the value of the oxygen index for the fire-protected polycaproamide fibres and by data from differential thermogravimetric analysis.

Stereoregularity of grafted polyacrylonitrile prepared by liquid phase graft polymerization to polycaproamide fibre

The stereoregularity of grafted polyacrylonitrile (PAN) was studied in polycaproamide (PCA)-PAN graft copolymers, prepared by chemically initiated liquid phase graft polymerization on fibres. It was found that the stereoregularity of grafted PAN cannot be reliably determined by 13C NMR spectroscopy. By IR spectroscopy, the presence of absorption bands characteristic of isotactic PAN triads was revealed in graft copolymers. These results were confirmed by X-ray structural analysis. By spectroscopic analysis of polyacrylic acid prepared by polymer-analogous transformation of PAN, the stereoregular isotactic structure of grafted PAN was established.

Role of diethylaminoethylmethacrylate in graft polymerization to a polycaproamide fibre

The participation of diethylaminoethylmethacrylate in the initiation of graft polymerization of this monomer to a polycaproamide fibre has been established by ESR and UV spectroscopy and colorimetry. The formation of an aminohydroperoxide during grafting has been demonstrated. The participation of the hydroperoxide of the monomer in graft polymerization is demonstrated by inhibition of the process in the medium in an inert gas.

Physicomechanical and spectral properties of modified fibre-forming polycaproamide

The physicomechanical characteristics of fibre based on polycaproamide which has been modified at the synthesis stage with 1–5% by wt. of sodium 4,4′-diaminostilbene-2,2′-disulfonic acid have been investigated. Spectral-luminescent properties of solutions and films of the modified polycaproamide have been described. An evaluation of the ability of two types of dye to dye the modified polycaproamide fibres has been carried out, and it has been found that the introduction of diaminostilbene fragments helps raise the dyeability of the fibres with basic cationic golden-yellow 2K.

Synthesis of graft copolymers of polycaproamide with polymethacrylic acid

The modification of polycaproamide fibres by graft polymerization of methacrylic acid in the presence of the K 2S 2O 8Na 2S 2O 8 redox system and copper ions is studied. A connection is established between the amount of monomer sorbed on the polymer base and the kinetics of the graft polymerization reaction. It is established that in the presence of this system with a considerable excess of reducing agent in the reaction solution a sufficient difference in the rates of the homo- and graft-polymerization rates is ensured, this determining the high effectiveness of grafting with hardly any formation of polymer.

Regeneration of ?-caprolactam from wastes in the manufacture of polycaproamide fibres and yarns

Regeneration of ?-caprolactam from wastes in the manufacture of polycaproamide fibres and yarns

Properties of polycaproamide fibres which have been modified by grafting polyacrylonitrile

The properties of modified polycaproamide fibres containing various amounts of grafted polyacrylonitrile have been investigated.

Spontaneous elongation of polycaproamide fibres, formed from the melt

Spontaneous elongation of melt-formed polycaproamide fibres has been investigated using infrared and small and wide angle X-ray diffraction spectrometry. The reason for this phenomenon was shown to be the crystallization of the polymer. The activation energy of this process is 26 kJ/mole.