聚乳酸/聚丁内酰胺电纺核-壳结构纤维的制备及性能

Preparation and Properties of PLLA/PBL Electrospun Fibers with Core-Sheath Structure

通过溶液静电纺丝法制备了基于聚L-乳酸/聚丁内酰胺(PLLA/PBL)共混体系的全生物基可降解纤维。通过扫描电子显微镜(SEM)、接触角测试、差示扫描量热(DSC)、X射线衍射(XRD)、透射电子显微镜(TEM)以及全反射红外光谱(ATR)等方法,表征并分析了PLLA与PBL的共混比例对纤维形貌、直径、亲水性、热性能及结晶性能的影响,并研究了共混纤维的内部结构。结果表明:PLLA与PBL以不同比例共混电纺均可得到形貌均匀的纤维,PLLA/PBL共混纤维的直径低于纯PLLA纤维的直径,且PLLA/PBL共混纤维的平均直径随PBL含量的增加而减小;PBL的加入没有明显改善PLLA/PBL共混纤维的亲水性,但对纤维中PLLA组分的结晶以及晶体的完善有阻碍作用;电纺过程中溶剂挥发导致的相分离使PLLA/PBL共混纤维形成了以PLLA为壳、PBL为核的核-壳结构。

Poly(L-lactide)(PLLA)and polybutyrolactam(PBL)are both biocompatible and biodegradable polymers.Here,bio-based and biodegradable fibers were electrospun from PLLA/PBL blend solutions dissolved in hexafluoroisopropanol(HFIP),the co-solvent of PLLA and PBL.The influences of PBL mass fraction on fiber properties including morphology,average diameter,thermal,crystallization and hydrophilicity properties were investigated by scanning electron microscope(SEM),differential scanning calorimetry(DSC),X-ray diffraction(XRD)and contact angle testing.The internal structure of blend fibers was confirmed by transmission electron microscope(TEM).Dichloromethane(DCM),the solvent of PLLA was used to etch the fibers to give a supplementary proof.It was found that beads free homogeneous fibers without band structure could be obtained from PLLA/PBL blends.The diameters of fibers distributed in a range of 0.1~1.6μm.The average diameters of PLLA/PBL blend fibers were lower than those of pure PLLA fibers and decreased with the increasing of PBL mass fraction.The crystallinity of PLLA in as-spun fibers was low,and it could be increased by cooling from 190°C that above the melting point of PLLA or annealing at 110°C above its glass transition temperature.Introducing PBL into PLLA fibers hindered the melt and annealed crystallization of PLLA.The reduction in the degree of PLLA crystal perfection was characterized by the obvious decrease in either PLLA crystallization temperature during cooling or the melting temperature in the second heating.The broadening of the half-peak width of PLLA crystal diffraction peaks was another evidence provided by XRD.All evidences from TEM observation and solvent etching experiment suggested that the fibers with core-sheath structures were obtained by single-nozzle electrospinning from solutions of PLLA/PBL blends.The phase separation occurred during the electrospinning process due to various segment mobility should be responsible for the fiber structure with PBL core and PLLA sheath.It could explain why the addition of hydrophilic PBL hardly improved the hydrophilicity of as-spun fiber surfaces.