Research On The Spinning And Modification Of Biological Polyester P(3HB-co-4HB) Fiber

Today oil reserves of our world is dwindling, and oil price is rising, global energy crisis has been increasing, environmental pollution is increasingly serious. The international context led to the emergence of a large number of biodegradable polymer materials, which can mainly be divided into three categories:chemical synthetic polymers, natural starch-based bio-degradable materials, and the biomass polyester polyhydroxyalkanoate (PHA). The polyhydroxy fatty acid ester materials due to its superior biodegradability, biocompatibility and outstanding mechanical properties has become a hot topic in the field of biodegradable polymer materials.The object of this paper is poly (3-hydroxy-butyrate-co-4-hydroxyl butyrate) [P (3HB-co-4HB)], whose mechanical properties are similar to the PE and PP, with the increase of 4HB content, the material transforms from brittle to the toughness, and the processing window is narrow, crystallization performance of P (3HB-co-4HB) is poor, the crystallization rate is slow, is easily to occur of secondary crystallization, the molding shrinkage rate is 1-2.5%.This article analysised the thermal performance of the P (3HB-co-4HB) by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) of, selected a suitable melt-spinning temperature of 125-150 ℃, P (3HB-co-4HB) fibers, P (3HB-co-4HB)/TiO2 fibers, P (3HB-co-4HB)/EVA fibers and P (3HB-co-4HB)/TiO2/EVA fibers were successfully prepared. Capillaryrheometer, thermal gravimetric analysis and single yarn strength tester were used to test the fheological property, thermal property, monofilament mechanical property and elasticity property of composites. The results shown:P (3HB-co-4HB), P (3HB-co-4HB)/TiO2, P (3HB-co-4HB)/EVA, and P (3HB-co-4HB)/TiO2/EVA composite materials melting are all pseudoplastic fluid, with the temperature rose, the apparent viscosity of the melt decreased, the value of non-Newtonian index n increased; with shear rate increased, the apparent viscosity decreased. P (3HB-co-4HB) and P (3HB-co-4HB)/TiC>2 were pseudoplastic fluids; TiO2 can improve the processing fluidity of the material effectively; also can improved the thermal stability; fracture strength of fibers were significantly reduced and flexibility recovery rate of fibers increased to 100% after TiO2 added in, and unwinding improved. P(3HB-co-4HB)/EVA blends had better rheology, crystallinity, thermal stability; the fracture strength of the fibers decreased with the EVA content increased, but the elongation at break was on the contrary; the elastic recovery rate of blend fibers reached 100%; moisture regain rate and drying shrinkage rate first increased and then decreased with EVA content increased. When TiO2 and EVA was both added to the matrix of P (3HB-co-4HB), the thermal stability of the composite materials were better than the pure P (3HB-co-4HB) fibers, but were not as good as P (3HB-co-4HB)/EVA binary blends fibers, and the mechanical properties of the ternary blend fibers were poorer than P (3HB-co-4HB)/EVA binary blend fibers.