Dyeing And Finishing Properties Of Biomass PHA Fibers

Polyhydroxyalkanoates(PHA) are linear polyesters which are produced by a class of hydroxy fatty acid. PHA has becomed one of the more popular current polymer materials because of its excellent biodegradability and biocompatibility. Therefore, the study has farreaching implications for PHA performance and fiber dyeing and finishing processes.In this paper,the basic properties,the structure changes after processing,and the dying properties has been investigated.By scanning electron microscopy, X- ray diffraction, thermal analysis and other means, were studied the surface morphology, structure and composition, crystalline properties, thermal and mechanical properties of PHA fibers. The results showed that, PHA fiber was smooth and shiny; the degree of crystallinity of about 54.59%, relatively high; breaking strength of 21.71 cN·dtex-1, elongation at break of 29.55%; poor heat resistance PHA fibers melt temperature of only 152.61 ℃.In order to provide the basis for the dyeing process conditions of PHA fibers, we determined the thermal stability, pH stability, oxidative stability and restore stability of PHA fiber. The results showed that the thermal stability of PHA fiber is poor. So the dry heat temperature should be controlled within 150 ℃, and the hot and humid temperature should be controlled in less than 110 ℃;The resistant to acids, oxidant and reducing agent was strong. It maintained a high degree of crystallinity and strength, handling 30 min even at 95 ℃.with a concentration of 10% sulfuric acid. However, the alkali resistance of PHA was poor, when the concentration of sodium hydroxide was 0.4%, the strength strength lost 25.70% and he degree of crystallinity also decreased.Selected different structural types of disperse dyes to study the kinetic and thermodynamic of PHA fibers. The results showed that,the dyeing on PHA by disperse dyes was corresponded to pseudo second-order kinetic models,and the adsorption process of disperse dyes onto PHA fit the Nernst adsorption model. The0DS of disperse orange 30 was-4.51 J·mol-1·K-1and the 0DH was-21.53 kJ·mol-1; The0DS of disperse blue 79 was-6.02 J·mol-1·K-1and the 0DH was-21.31 kJ·mol-1.The 0DS and DH0 of the two disperse dyes were negative, indicating that the dyeing process was a spontaneous exothermic process. Reaserched the factors influencing the disperse dyeing on PHA,the optimum conditions as follows: pH = 5, the temperature 100 ℃, dyeing 60 min. Disperse dyes had a poor buildingup property. Soaping fastness of dyeing fibers reached 4 level above, basically meeting the polyester fabric requirements.Selected different structural types of cationic dyes to study the kinetic and thermodynamic of PHA fibers. The results showed that,the dyeing on PHA by cationic dyes was corresponded to pseudo second-order kinetic models,and the adsorption process of disperse dyes onto PHA fit the Nernst adsorption model. The0DS of cationic red X-GRL was-9.43 J·mol-1·K-1and the 0DH was-14.29 kJ·mol-1; The0DS of cationic red GTLwas-8.48 J·mol-1·K-1and the 0DH was-14.60 kJ·mol-1.The 0DS and DH0 of the two cationic dyes were negative, indicating that the dyeing process was a spontaneous exothermic process. Reaserched the factors influencing the cationic dyeing on PHA,the optimum conditions as follows: pH = 5, the temperature 100 ℃, dyeing 60 min. The six cationic dyes all had poor building-up property. Soaping fastness of dyeing fibers reached 4 level above, basically meeting the polyester fabric requirements.