Preparation And Properties Of Different Core(PEO)-Shell(PHB) Structured Ultrafine Fibers

At present,with the increase of human production activities,Air haze,oil spill and other problems are affecting the ecological environment and human health occasionally.The research and development of polymer materials with strong adsorption ability,high selectivity and environment friendliness have become a hot topic.In this study,the different core(PEO)-shell(PHB)structured ultrafine fibers were prepared by coaxial electrospinning technology using the biodegradable polymer material Poly?-hydroxybutyrate(PHB)and hydrophilic non-degradable polymer polyoxyethylene(PEO)as the substrate.The influence of the dynamic rheological properties of PHB and PEO spinning solutions at different temperatures and the electrospinning conditions on the morphology,structure and properties of the fibers were studied.The morphology,core-shell structure,thermal properties,crystallization properties,mechanical properties and hydrophilic properties of the prepared fibers were characterized and analyzed by SEM,TEM and ATR-FTIR.The dynamic rheological properties of PHB and PEO spinning solutions at different temperatures were studied by using a rotating rheometer.The results show that temperature has no obvious effect on the spinnability of PHB solution,but too high temperature is not conducive to spinning,and the spinnability increases with the increasing of shear rate.for PEO solution,increasing the temperature of spinning solution is beneficial to widening the spinning window.the spinning solution of PHB and PEO was stable at 25?,while the stability decreased with the extension of the stress time at 35? and 45?,but the solution was stable in a short time of 1min.the spinning solutions of PHB and PEO showed the characteristics of shear thinning.By using coaxial electrospinning technology and regulating the spinning process conditions,core(PEO)-shell(PHB)ultrafine fibers with smooth and non-porous,helical and non-porous,helical and porous can be prepared.The thermal stability of core(PEO)-shell(PHB)ultrafine fibers with porous helical structure is higher than that ofpure PHB fibers and pure PEO fibers;porous core(PEO)-shell(PHB)ultrafine fibers can be prepared by using PHB as the core component and PEO as the shell component.Ordered core(PEO)-shell(PHB)ultrafine fibers with average diameter of 0.57?m ~1.27?m were prepared by using high-speed rotating receiving roller as coaxial electrospinning receiving device.The fiber contains ? crystal of component PHB and monoclinic crystal of component PEO.PEO macromolecular chain is easy to develop from folded chain crystal to extended chain chip in the process of high-speed stretching,and PHB component is not affected.The diameter and crystallinity of the fiber vary with the condition of electrospinning.taking a single factor as the variable,the corresponding fiber film at the spinning voltage of 18 kV,the injection speed of 0.07mm/min and the collection distance of 8cm all have high mechanical properties.the thermal stability of each component of ordered core(PEO)-shell(PHB)microfiber is higher than that of the pure component.The results of hydrophobicity and oil absorption test showed that the hydrophobicity and oil absorption of the multi-structure core(PEO)-shell(PHB)ultrafine fiber membrane were higher than pure PHB fiber membrane,but the oil retention rate was lower than PHB fiber membrane.