Study On The Formation Mechanism And Properties And Structure Of PAN/SPI/PU Blend Fibres

Soybean protein isolated (SPI) has been considered recently as an alternative to petroleum polymer in the manufacture of adhesives, plastics, textiles et al. SPI is available from renewable resources and biodegradable. Utilizing SPI for materials will help alleviate environmental and petroleum resource problems and add value to agricultural by-products. Polyacrylonitrile (PAN) and polyurethane (PU) are general polymer material, and they have excellent performance, respectively. Blending, which may combine the advantages of both components, is an important method in polymer manufacture.In this dissertation, the mixture of Dimethyl Sulphoxide (DMSO) was used as solvent, and the blend solutions of PAN-SPI-PU were prepared. The blend fibres were processed by wet-spinning and properties of fibres were studied. Their main results obtained are as follows:First, the rheological properties of the PAN/SPI/PU blend solutions in DMSO were studied. The effects of SPI and PU on the rheological properties of PAN solutions are very different. The Non-Newtonian index of PAN/SPI blend solutions decrease and corresponding structure viscosity index of that increase with the increase of SPI content on the whole. The fluid properties of PAN solution is worsened with the addition of SPI. However, Those of PAN/PU blend solutions are opposite, and the fluid properties of PAN solution are improved with the addition of PU. The rheological properties of PAN/SPI/PU blend solutions are affected by the contents of SPI and PU. In any case, the increase of temperature contributes to the improvement of the fluid properties of blend solutions.Second, the effect of temperature and concentration of coagulation bath, the multiple and corresponding distributive proportion of multiple drawing, temperature and time of drying, the type and concentration of crosslink agent on the properties of blend fiber were investigated. The result shown it is better to get good performance fibres when the concentration of coagulating agent was 60%, and the temperature of coagulation bath was 22°C, the drawing multiple in washing bath was 1.5～2 and the drying time was 15～20 minutes at 120°C .The effect of glutaraldehyde and glyoxal as cross-linking agent at coagulation bath on blend fiber were studied. It was found that the mechanical properties of fibres used by glyoxal are improved significantly.Finally, the structure and properties of blend fibres were investigated. The results of FTIR spectroscopy shown that the blend fibres were composed by PAN、SPI and PU, and the concentration of SPI in blend fibres determinately increased with increasing of addition of SPI by using enzymatic hydrolysis . The mechanical properties of fibres had not much change but the tensile strength of blend fibres decreased a little. The moisture regain and biological degradation of blend fibres increased with increasing of SPI content. However, the flexibility of fibres was not obviously improved with increasing of PU content may be due to the poor compatibility between PAN,SPI and PU. The dye uptake of blend fiber increased with increasing of SPI content.