聚L-乳酸/菜籽蛋白共混纳米纤维毡的制备与表征

以聚L-乳酸、菜籽蛋白为原料,高压静电纺丝制备聚L-乳酸(PLLA)/菜籽蛋白共混复合纳米纤维毡,考察了不同电压、极距和三氟乙酸添加量对纳米纤维形态及直径的影响,采用傅里叶变换红外光谱(FT-IR)、扫描电镜(SEM)和X-射线衍射(XRD)对相关产物进行结构表征。结果表明:复合纤维中PLLA与菜籽蛋白之间以氢键结合,PLLA的结晶性能降低;PLLA纺丝溶液中,菜籽蛋白的三氟乙酸溶液的适量引入可显著提高纺丝速率。在PLLA质量浓度为24%的氯仿溶液中,6.5%菜籽蛋白的三氟乙酸溶液加入量为0.25 mL,电压16 kV,极距10 cm的条件下,可快速制备平均直径622 nm的PLLA/菜籽蛋白复合纳米纤维毡,纺丝速率达到5.2 mg/min。     

聚乳酸纤维的制备及性能研究进展

综述了聚左旋乳酸(PLLA)纤维的制备方法、性能和应用的研究进展。PLLA纤维的制备方法主要包括溶液纺丝、熔融纺丝和静电纺丝。通过调控纺丝工艺、共混改性、物理改性、化学改性等方法,可改善PLLA纤维的生物降解性、力学性能、耐热性能、阻燃性、抗菌性、抗紫外性等综合性能。指出PLLA纤维是未来可持续发展的必然趋势,应在原料成本、纤维改性、纺丝工艺、纤维后处理等方面深入研究,扩大PLLA纤维的应用领域。     

可降解多元混构型纤维的制备及降解性能研究

将聚羟基丁酸戊酸酯(PHBV)、左旋聚乳酸(PLLA)以不同比例共混,采用干法纺丝工艺制备复合可降解纤维。运用扫描电子显微镜和X射线衍射仪对纤维的微观形貌和结构进行分析。确定干法纺丝工艺参数为:卷绕速度28.5 m/min,拉伸倍数3倍,拉伸温度90℃。当PHBV与PLLA质量比为1∶1时,所得纤维强度可达2.8 c N/dtex。通过力学以及结晶性能的变化等研究纤维的降解性能。随降解时间的增加断裂强度与断裂伸长率均呈下降趋势,纤维的规整结构遭到破坏,结晶度有所下降。共混比不同的复合纤维在同一周期内其降解程度不同,当PLLA质量分数达80%,降解周期为50 d时,呈现脆性断裂,断裂强度仅为降解前的1/3。     

多级结构PHB基电纺纤维膜的制备及性能研究

以聚β-羟基丁酸酯(PHB)为基体,左旋聚乳酸(PLLA)和聚氧乙烯(PEO)为第二组分,采用多层静电纺丝法制备了三层复合的PHB/PLLA/PHB,PHB/PEO/PHB,PHB/PLLA/PEO多级结构PHB基纤维膜,研究了多级结构PHB基纤维膜的形貌、结晶行为、热性能和亲水性能。结果表明:多级结构纤维膜中PHB组分的平均直径为770~790 nm,PEO的平均直径为280~290 nm,PLLA的平均直径为400~410 nm;PHB,PLLA组分在多级结构纤维膜中的晶型均为α晶型,PEO组分为单斜晶型,多级结构PHB基纤维膜中各组分的热性能没有受到影响;多级结构纤维膜的亲水性由强到弱的顺序依次为PHB/PEO/PHB纤维膜、PHB/PEO/PLLA纤维膜、PHB/PLLA/PHB纤维膜、PHB纤维膜,多级结构可改善PHB电纺纤维膜的亲水性。     

立构复合聚乳酸/碳纳米管静电纺丝纤维膜的制备及其结晶性能

利用羟基化的碳纳米管(CNT-OH)和辛酸亚锡分别作为引发剂和催化剂,右旋丙交酯在130℃下开环聚合反应,对碳纳米管(CNT)进行了改性处理。红外光谱和热失重分析结果表明,CNT被成功改性,聚右旋乳酸(PDLA)在CNT上的接枝率为34.8%。进一步通过静电纺丝法制备了聚乳酸/功能化碳纳米管(PLLA/CNT-f-PDLA)的复合纤维膜,纤维平均直径为890 nm。利用红外光谱和X射线衍射技术研究了复合纤维膜的结晶行为和晶体结构。结果表明,在120℃热处理0.5 h后的复合纤维膜中,只生成立构复合晶体(sc),无PLLA或PDLA的同质晶体(hc)产生,而且由于CNT-f-PDLA在PLLA基体中的良好分散性以及CNT的异相成核作用,相对于PLLA/PDLA复合纤维膜,PLLA/CNT-f-PDLA复合纤维膜的立构复合结晶度得到了提高。     

聚乳酸/聚乙烯醇纳米纤维的制备及结构

以二甲基亚砜为溶剂,制备不同配比的聚乳酸(PLLA)和聚乙烯醇(PVA)的混合溶液,静电纺丝制得PLLA/PVA纳米纤维。采用红外光谱仪、原子力显微镜等对PLLA/PVA纳米纤维结构与性能进行了表征。结果表明:PLLA/PVA纳米纤维中PVA上的羟基与PLLA上的羰基形成了氢键,PLLA与PVA之间存在一定的相互作用,但PLLA/PVA纳米纤维存在相分离现象;混合溶液的PLLA质量分数为11%,PVA质量分数为8%时可以得到较好的PLLA/PVA纳米纤维,但PVA质量分数为6%时出现液滴及珠丝,PVA质量分数为4%时,不能制得纳米纤维。     

熔纺聚乳酸纤维的结构与性能研究

通过熔融纺丝法制备了生物可降解左旋聚乳酸(PLLA)纤维,对纤维进行了拉伸和热定型等后处理,用电子单纤维强力仪和X-射线衍射仪研究了PLLA纤维的力学性能和结晶性能,讨论了纺丝温度、拉伸倍数、定型时间和定型温度等对纤维力学性能的影响。结果表明,当纺丝温度为200℃时,纤维可纺性最好。当拉伸倍数为4倍,热定型温度为60℃,定型时间为30min时,PLLA纤维具有最佳的力学性能,其晶区具有α晶型结构。     

PHB/PLLA共混电纺纤维可纺性的研究

采用静电纺丝法制备了聚β-羟基丁酸酯/左旋聚乳酸(PHB/PLLA)共混纤维,探讨了静电纺丝工艺及PHB/PLLA共混电纺纤维的可纺性。结果表明:对共混溶剂氯仿/N,N-二甲基甲酰胺(CF/DMF)体系,随DMF在共混溶剂中含量增加,PHB/PLLA纤维形态由连续的纤维变为微球;对CF溶剂体系,随纺丝溶液浓度增加,PHB/PLLA纤维形态从微球状变为珠状体,再变成纺锤体,最后形成连续纤维;适宜的PHB/PLLA共混电纺纤维的工艺条件如下:PHB/PLLA质量比为1∶1,溶剂为CF,电纺溶液质量分数为4%,推进速度为0.15 mm/min,板间距17 cm,电压18 kV。     

PLLA/CS-g-PCL电纺纤维膜的制备及结构性能表征

将自制的壳聚糖接枝聚己内酯(CS-g-PCL)与聚左旋乳酸(PLLA)分别溶解在二氯甲烷/N,N-二甲基甲酰胺(体积比为7∶3)共混溶剂中制备出相同质量浓度的均匀溶液,然后将两种溶液以不同的质量比共混制备PLLA/CS-g-PCL混合纺丝液,通过静电纺丝制备PLLA/CS-g-PCL电纺纤维膜,借助扫描电镜、傅里叶变换红外光谱、接触角测量仪及强度拉伸仪等测试手段对其结构和性能进行研究。结果表明:当PLLA/CS-g-PCL混合溶液的质量浓度为0.15 g/m L,PLLA与CS-g-PCL质量比8∶2时,PLLA/CS-g-PCL电纺纤维膜的纤维表面光滑,平均直径为760.1 nm,纤维膜的孔隙率为84.6%,接触角为73°,吸水率为482.2%,拉伸强度为3.54 MPa,拉伸模量为125.4 MPa,断裂伸长率为93.8%;相比于纯PLLA电纺纤维膜,PLLA/CS-gPCL电纺纤维膜的亲水性和吸水性得到了改善,模量和断裂伸长率也得到了提高。     

PLLA/PCL共混纤维的力学性能研究

本文以二氯甲烷为溶剂,采用离心纺丝制备出聚乳酸-聚己内酯纤维,通过FT-IR、DSC、SEM、接触角、拉伸测试表征了所得产品,并考察了浓度、配比、转速等条件对纤维结构和形貌的影响。最终得到性能优异的聚乳酸-聚己内酯离心纺丝纤维。研究结果表明:PLLA/PCL共混物为不相容体系,并相互限制对方的结晶行为;在PLLA/PCL共混体系中,PCL可作为PLLA结晶过程的异相成核剂,并促使PLLA的熔融重结晶;离心纺丝最佳纺丝液浓度为12%、最佳组分比(PLLA:PCL)为7:3、最佳离心转速为10 000r/min;PLLA/PCL共混物的接触角处于单组份值之间,表现为疏水性;PLLA/PCL的共混离心纺丝样品力学强度得到显著的增加,韧性也有一定程度的改善。     

一步法制备聚乙醇酸纤维的工艺及其性能研究

以聚乙醇酸(PGA)为原料,采用熔融纺丝-拉伸-卷绕一步法工艺制备PGA纤维,研究了工艺路线对纤维结构的影响,重点讨论了拉伸倍数对纤维的结构、力学性能、回弹性能及亲水抗静电性能的影响.结果表明:采用熔融纺丝-拉伸-卷绕一步法工艺,可以较好地实现PGA纤维的热拉伸,纤维与纤维之间不易黏结,纤维结构的稳定性得到改善;随着拉...     

Effect of Poly(L-lactic acid) on Hydrolytic Degradation of Poly(glycolic acid)

The in-vitro degradation behavior of poly(glycolic acid) (PGA) rods and the composite rods containing poly(L-lactic acid) (PLLA) were investigated via mass loss, pH value change, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Since the degradation rate of PLLA is lower than that of PGA, PLLA/PGA composite rods exhibit a slower degradation rate in comparison with PGA. This finding indicated that it was possible to control the degradation rate of the composites by changing their composition. This result indicates that this kind of composite biomaterial may be applicable to devices for the need of prolonged degradation.     

Electrospun fibers of poly(l‐lactic acid) containing lovastatin with potential applications in drug delivery

Lovastatin (Merck's Mevacor) is a statin drug designed to lower cholesterol, and reduce the risk of heart attack and stroke. We use electrospinning to combine the biomedical properties of lovastatin with the advantages of electrospun fibers to prepare a composite biomaterial for lovastatin delivery. Poly(l ‐lactic acid) (PLLA), a biodegradable and biocompatible polymer, was co‐spun with lovastatin. Incorporation of lovastatin at 5 or 10 wt % improved fiber alignment and surface smoothness, and increased fiber diameter. Influence of lovastatin on the phase structure (crystal, mobile amorphous, and rigid amorphous fractions) was investigated using scanning calorimetry and synchrotron X‐ray scattering. Addition of lovastatin resulted in increased crystallinity and reduced mobile amorphous fraction. PLLA fibers were characterized in terms of their drug release kinetics in comparison to PLLA film. High drug entrapment efficiency (ranging from 72% to 82%) and appropriate release profiles were achieved. In vitro drug release studies demonstrated that release occurred in two stages: an initial rapid release over the first day and a slower second stage of release which approached a plateau after 7 days. PLLA fibers have a higher release rate than comparable film. Electrospun biomaterial fibers of PLLA provide a promising new release strategy for delivery of lovastatin. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45287.     

热处理时间对PLLA/PDLA纤维结构及性能的影响

对采用熔融纺丝及热牵伸得到的左旋聚乳酸/右旋聚乳酸(PLLA/PDLA)牵伸丝在200℃下进行了不同时间的热处理,并对热处理前后PLLA/PDLA纤维热性能、结晶结构、表面形貌等进行了研究。结果表明:经过热处理后,DSC升温曲线中仅存在sc立构晶熔融峰;当热处理时间为1 min时,即可得到仅含sc立构晶的PLLA/PDLA纤维,随着热处理时间的延长,sc立构晶的熔融峰分峰现象有所减弱,结晶度及晶区取向度均有不同程度的提高,同时晶粒尺寸变小。SEM照片显示,经热处理后PLLA/PDLA纤维表面呈现不规则的突起。     

Investigations of the preparation technology for polyglycolic acid fiber with perfect mechanical performance

Polyglycolic acid (PGA) fibers were prepared by melt‐spinning process in this report. The effects of spinning parameters, such as windup rates and drawn ratio, on the mechanical properties of the fibers were discussed by analyzing the internal stress of as‐spun fibers, axial sound velocity, fiber tenacity, etc. The results showed that windup rate had a slight effect on the macromolecular orientation degree of the as‐spun fibers, which was quite unusual for melt spinning, whereas, the subsequent drawing process effectively increased the macromolecular orientation degree of the PGA fibers and consequently increased the tensile strength of the fibers. Low internal stress of as‐spun fibers obtained at lower windup rate led to higher drawing ratio, and the drawn fibers possessed relatively excellent mechanical properties. As a contrast, higher windup rate resulted in the strong internal stress of the as‐spun fibers, which had a negative influence on the drawing process, and so the tensile strength of the drawn fibers was relatively poor. Therefore, PGA fiber with perfect mechanical performance could be prepared at the technical parameters of lower windup rate and higher drawing multiples as well as slow drawing rate. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

聚乙交酯纤维的结构及其降解性能

纺制了聚乙交酯(PGA)纤维,并对其进行了不同温度和时间的热处理。对处理后PGA纤维的结构进行了测试,并将其放置于恒温箱的磷酸盐缓冲液中进行两周降解处理,研究了不同热处理工艺下PGA纤维的结构及降解性能。试验结果表明:随着热处理温度的提高,PGA纤维材料的晶区取向度变化不大,结晶度逐渐增大,晶粒尺寸也相应发生变化;在试验条件下,经过恒温缓冲液两周时间的降解处理,纤维的强度保持率随热处理温度提高呈现先增大后降低的趋势,纤维的强度保持率在110℃出现最大值;同时,在热处理温度110℃时,随着热处理时间的延长,PGA纤维的强度保持率增加。     

Characterization of poly(L‐lactic acid) fibers produced by melt spinning

Biodegradable poly(L ‐lactic acid) (PLLA) fibers were processed by a two‐step melt‐spinning method (melt extrusion and hot draw) from PLLA with three different viscosity‐average molecular weights (494,600, 304,700, and 262,800). Before spinning, the polymer flakes were first milled into powders and dried under vacuum. Viscosity‐average molecular weight of PLLA following the fabrication process was monitored. Tensile properties of as‐spun and hot‐drawn fibers were investigated. Morphology of the PLLA fibers was viewed under a scanning electron microscope. Crystallinity of these fibers was assessed by thermogram analysis of differential scanning calorimetry. Results showed that the extent of decrease in the viscosity‐average molecular weight of PLLA dropped sharply by 13.1–19.5% during pulverization and by 39.0–69.0% during melt‐extrusion. The hot‐draw process in this study had a little effect on the viscosity‐average molecular weight of PLLA. Smoother fibers could be obtained for the die temperature at least 230°C for raw materials with higher crystallinity (more than 75%) and at least 220°C for raw materials with lower crystallinity (about 60%). The as‐spun fibers showed crystallinity of 16.5–22.8% and the value increased to 50.3–63.7% after hot draw. Tensile moduli of the as‐spun fibers were in the range of 1.2–2.4 GPa, which were raised to 3.6–5.4 GPa after hot draw. The final PLLA fibers with 110–160 μm diameters showed tensile strengths of 300–600 MPa. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 251–260, 2001     

In vitro chemical degradation of poly(glycolic acid) pellets and fibers

The influence of macroscopic dimensions, heat treatment, and polymer morphology on the chemical degradation of poly(glycolic acid) (PGA) fibers and pellets was examined in media of different pH values by monitoring the sample mass, dimensions, crystallinity, mechanical strength, and surface character. The degradation was found to be chemically controlled and independent of fiber size. The rate was an order of magnitude faster in alkaline vs. acidic media. In general, the pellets degraded faster than fibers, and while the latter showed little surface deterioration, scanning electron photomicrographs of the pellets revealed considerable surface degradation with circumferential microcracks progressing into longitudinal cracks with increasing immersion times and pH. Concomitantly, DSC measurements showed a steady increase in crystallinity for both fibers and pellets. The fiber tensile strength decline was independent of diameter and more drastic in alkaline media. Additionally, the heat-treated fiber was always stronger than the non-heat-treated one. It is concluded that crystallinity and polymer chain orientation, in addition to immersion media, influence PGA degradation. Also, the loss in strength results from chain scission in the amorphous regions while mass loss occurs when polymer chains become small enough to be soluble. These different variables offer a means of modifying PGA fiber tensile properties.     

马来酸酐接枝改性PP/PS皮芯复合纤维的研究

用自制的马来酸酐接枝聚苯乙烯为相容剂,与改性聚丙烯(PP)混合造粒作为芯层料,以聚苯乙烯和相容剂为皮层料,将芯层料与皮层料以体积比1:1的比例熔融复合纺丝,制得皮芯复合纤维,对改性PP的结构和皮芯复合纤维性能进行了研究。结果表明:马来酸酐已接枝到聚丙烯上,皮芯复合纤维相对于纯PP纤维,其熔点下降,结晶温度上升;电镜分析表明皮芯复合纤维的皮芯之间没有明显的裂缝,其相容性得到改善;与没有改性的PP与聚苯乙烯复合纤维比较,皮芯复合纤维的力学性能得到明显的提高。