EXTRACTION OF RUBBER FROM LATEX BY HYBRID COAGULANT BASED ON POLYDIMETHYLDIALLYLAMMONIUM CHLORIDE AND VISCOSE FIBER

In the proposed work, the possibility of using a hybrid coagulant based on a polymer cationic electrolyte-VPK – 402 (poly-N,N-dimethyl-N, N-diallylammonium chloride) in combination with viscose fiber in the technological process of separating SKS-30 ark rubber from latex is considered. The influence of the consumption of a hybrid coagulating agent, viscose fiber and its dosage, as well as the process temperature on the reduction of the aggregate stability of styrene-butadiene latex is considered. The influence of viscose fiber on the physical and mechanical properties of vulcanizates is established. At the same time, a number of features were noted consisting in a decrease in the aggregate stability of latex butadiene-styrene rubber during its coagulation with a hybrid coagulant. It was found that the use of a hybrid coagulant can reduce the consumption of cationic polyelectrolyte by up to 30%. It is shown that in the multicomponent system under consideration, several processes can occur simultaneously, which lead to the destabilization of latex dispersions. The use of a hybrid coagulant, including cationic polyelectrolyte, provides a combined effect of the bridging and neutralization mechanisms of violation of the aggregate stability of the dispersion. The presence of viscose fiber in the dispersed phase leads to an additional coagulating effect-adagulation, which is a kind of heterocoagulation. This may be due to the difference in surface potentials between the latex globules and the fiber additive. It is established that the temperature regime of the process of isolation of rubber from latex does not significantly affect the completeness of the extraction of rubber from latex. A decrease in the content of components of the emulsion system in wastewater discharged from the shops producing rubbers by emulsion polymerization was noted. According to the main physical and mechanical parameters, rubbers, rubber mixtures and vulcanizates prepared on their basis meet the requirements.

The Improving properties of Viscose fabric by water repellent finish

Viscose as cellulosic origin, the cheapest of all cellulosic fabrics could be the best alternative. Viscose is manufactured from regenerated cellulose. In order to manufacture viscose, pulp of bamboo is treated with aqueous sodium hydroxide to form alkali cellulose. This alkali cellulose is then treated with carbon disulfide to form sodium cellulose xanthate. The xanthate is then dissolved in aqueous sodium hydroxide and allowed to depolymerize. After depolymerization, rayon fiber is produced from the ripened solution. Viscose is primarily employed in apparels, upholstery fabric, industrial clothing, and medical hygiene. Apparels, upholstery fabric, and industrial clothing segments account for key share of the viscose market. The medical hygiene segment is anticipated to expand during the forecast period. Demand for viscose fiber is anticipated to increase significantly in the near future due to the rise in global population, increase in standard of living, and growth in disposable income. Viscose is an eco-friendly product; thus, increase in awareness about eco-friendly products and decrease in production of cotton are estimated to augment the demand for viscose fiber. Viscose fabric exhibits some similar properties compared to cotton except its poor wet strength due to higher moisture regain. In this study, chemical finishes by different cross-linkers were applied to improve the wet strength of the viscose fabric. For this purpose, water repellent finishes were applied. Water repellent finish helped in reducing the molecular barrier around the individual fibres that lowered the surface tension of the fabric. It reduces the absorbency of viscose fabric hence leads to higher wet strength. Therefore, the treated viscose fabric exhibited better wet strength after applying water repellent finishes on it. Scanning electron microscope (SEM) was used to examine the surface of the fabric treated with chemicals. Tensile strength of viscose was increased 24.6%.

Study on structure and properties of natural indigo spun-dyed viscose fiber

To improve the level dyeing property and colorfastness of natural pigment-dyed cellulose fiber, a study on the structure and properties of natural indigo spun-dyed viscose fiber was carried out systematically. Herein, the natural pigment-dyed cellulose fiber was prepared by wet-spinning technique, and the microstructure of the colored fiber was comprehensively studied. Fabrics with different color depths were obtained by adjusting the color value and the content of indigo pigment. The natural indigo was evenly embedded in the viscose fiber, and the results indicated the existence of a direct ratio relationship between the performance of natural indigo and the color depth of the fiber. The level dyeing property and colorfastness of the fabric were tested. The fabric exhibited excellent dyeing uniformity, as indicated by the relative standard deviation of the surface color depth value on the fabric, which was no more than 2.39%. The colorfastness of natural indigo spun-dyed fiber was outstanding even when mordant was not used in the production process. The colorfastness to artificial light could reach grade 5, the fastness to washing with detergent reached grade 3–4, the fastness to rubbing reached grade 4–5, and that to high temperature reached grade 4–5. These results can possibly promote the future use of natural dyes in the fiber produced by a spun-dyeing technique.