Imparting enhanced hydrophobicity to polyester fabrics: Formation of ultrathin water-repelling coatings on the fiber surface

A new technology for hydrophobization of synthetic fiber materials was described. This technological approach is based on formation of nanosized fluoropolymer coatings from solutions of low-molecularweight fraction of ultradispersed polytetrafluoroethylene and tetrafluoroethylene telomers. The mechanism of formation of protective coatings was described, and the properties of polyester materials thus modified were presented.     

Analysis of a polytetrafluoroethylene coating deposited onto polyester fibers from supercritical carbon dioxide

A low-molecular-weight polytetrafluoroethylene coating deposited onto a polyester textile material from supercritical carbon dioxide with the aim to make the material hydrophobic was analyzed. The hydrophobic properties of the coating were examined in comparison with those of the hydrophobizing agent produced by Nuva (Switzerland).     

Ultrathin Hydrophobic Coatings Obtained on Polyethylene Terephthalate Materials in Supercritical Carbon Dioxide with Co-Solvents

The surface properties of ultradisperse polytetrafluoroethylene coatings on polyethylene terephthalate materials modified in a supercritical carbon dioxide medium with co-solvent additions (aliphatic alcohols) were analyzed. An atomic force microscopy study revealed the peculiarities of the morphology of the hydrophobic coatings formed in the presence of co-solvents. The contribution of the co-solvents to the formation of the surface layer with a low surface energy was evaluated from the surface energy components of the modified polyester material. The stability of the coatings against dry friction was analyzed.

     

Hydrophobization of polyester textile materials with telomeric tetrafluoroethylene solutions

Hydrophobic coatings formed on a polyester fabric by treatment with telomeric solutions prepared by a radiation-chemical procedure in acetone and butyl chloride were studied by IR spectroscopy (MATIR), energy-dispersive analysis, and atomic force microscopy. The hydrophobic properties of the textile material were evaluated by procedures traditional for textile chemistry. Conditions determining the formation of a thin, highly hydrophobic, uniform, and flawless coating resistant to the effect of operation factors were suggested.     

Control of the Sorption Properties and Wettability of a Nonwoven Polypropylene Material by Direct Gas Fluorination

The effect of direct gas fluorination on the surface properties of a nonwoven polypropylene material was studied. Direct gas fluorination with mixtures of different compositions allows directional variation of the surface properties of the nonwoven polypropylene material. The surface becomes more hydrophobic when using a mixture of fluorine and nitrogen but less hydrophobic when using a mixture of fluorine, oxygen, and nitrogen. The modification leads to changes in the chemical composition of the surface and in the roughness of the material. The nonwoven polypropylene materials thus obtained exhibit increased sorption capacity for spent oil or water, respectively. Variation of the properties of the nonwoven polypropylene material allows expansion of its applications.

     

Modification of polyester fibrous materials with surface barrier discharge for making them more hydrophilic

The possibility of using surface barrier discharge for the surface modification of polyester fabrics with the aim of making them more hydrophilic was studied. The action of surface-barrier discharge leads to the formation of hydrophilic oxygen-containing groups on the surface of polyester fabrics owing to weak degradation of poly(ethylene terephthalate) macromolecules, and the thread surface becomes rougher on the nanolevel. This leads to a considerable decrease in the contact angle and to an increase in the wettability of the polyester fabric, i.e., the fabric becomes considerably more hydrophilic. Modification of the polyether fabric with surface barrier discharge does not cause appreciable decrease in the strength and breaking elongation of the material.     

Ethylene terephthalate oligomers in the processes of modification of polyester fabrics in supercritical carbon dioxide

The influence of the conditions of processing of polyester fiber material in the supercritical carbon dioxide (SC-CO₂) medium on the localization of ethylene terephthalate cyclic oligomers on the surface of fibers is studied. It is shown that cyclic oligomers are deposited on the surface of polyester fiber materials in the form of large associates. The mechanism of migration of oligomers from the interior of polyester fibers plasticized in the SC-CO₂ medium is considered. Recommendations to minimize the amount of surface oligomers in the dyeing of polyester fiber materials in SC-CO₂ are given. It is shown that the deposition of oligomers on the surface of polyester fabric does not adversely affect the quality of their hydrophobization with ultrafine polytetrafluoroethylene in the SC-CO₂ medium.