静电纺丝素/胶原/聚合物复合纤维的制备及其力学性能的研究

目前,将天然高分子蛋白和聚合物共混利用静电纺丝法制作各种组织工程支架材料倍受关注。基于这种研究背景,在本文中利用静电纺丝技术,制备了丝素(SF)/胶原(COL)/聚左旋乳酸(PLLA)和SF/COL/聚左旋乳酸-己内酯(PLCL)两种共混复合纤维膜,通过扫描电镜(SEM)对纤维形态结构分析,发现复合纤维形貌良好,直径较为均一。同时改变纺丝液中高分子蛋白的比例,复合纤维的直径也随之减小。此外,对复合纤维进行了力学性能测试,发现随着聚合物含量的增加,复合纤维膜的力学性能得以改善,SF/COL/PLCL组复合纤维的拉伸性能明显优于SF/COL/PLLA组。     

静电纺丝制备醋酸纤维素复合纳米纤维的研究进展

静电纺丝技术就是通过带电聚合物溶液或熔体的喷射来制备纳米纤维,是一种制备纳米纤维材料简单有效的技术。醋酸纤维素(CA)易溶于有机溶剂,常作为纤维素的替代材料应用于静电纺丝领域。本文总结了近年来国内外采用静电纺丝技术制备CA复合纳米纤维的研究新进展,重点介绍了CA/CNTs复合纳米纤维、CA/金属粒子复合纳米纤维、CA/金属氧化物复合纳米纤维、CA基载药复合纳米纤维、CA/PAN复合纳米纤维、CA/PVA复合纳米纤维、CA/CS复合纳米纤维等CA复合纳米纤维的研究进展以及潜在的应用领域。     

Eu（TTA）3AA-NBR/PVP同轴超细纤维的制备及荧光性能研究

用同轴静电纺丝制备了含有稀土铕配合物(Eu(TTA)3AA)的芯-壳结构的丁腈橡胶/聚乙烯吡咯烷酮(NBR/PVP)超细荧光纤维。考察了在外层PVP纺丝参数不变的情况下,改变芯层丁腈橡胶纺丝液的纺丝速度、Eu(TTA)3AA含量等对纤维形貌的影响。通过研究Eu(TTA)3AA-NBR/PVP同轴超细纤维中Eu(TTA)3AA微观结构、含量与纤维的荧光性能之间的关系,发现在同轴纤维形成过程中由于溶剂的快速挥发可使Eu(TTA)3AA形成无定形结构,进而在纤维中形成分子簇级别的分散,在Eu(TTA)3AA含量为30%时,同轴纤维比Eu(TTA)3AA粉末的荧光强度提高了2倍。     

Bi_(20)TiO_(32)/聚丙烯腈复合纳米纤维的制备及其对异丙隆的光催化降解性能

采用溶剂热法制备了可见光响应型光催化剂Bi_(20)TiO_(32),为了实现该光催化剂的固定化负载,进一步以Bi_(20)TiO_(32)和聚丙烯腈(PAN)为原料,通过同轴静电纺丝法制备了不同光催化剂含量的Bi_(20)TiO_(32)/PAN复合纳米纤维。通过这一途径一方面可以便于光催化剂的回收利用,另一方面纳米纤维结构可以提高光催化剂与有机污染物反应的接触面积。采用X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、紫外-可见漫反射光谱(UV-Vis DRS)和氮气吸附-脱附法对样品的物相组成、形貌结构、光谱吸收和比表面积等进行表征。研究了在可见光照射下Bi_(20)TiO_(32)/PAN复合纳米纤维膜对苯脲类农药异丙隆的光催化降解性能。结果显示,制备的Bi_(20)TiO_(32)光催化剂禁带宽度为2.35 eV,属于典型的可见光响应型光催化剂。制备的Bi_(20)TiO_(32)/PAN复合纳米纤维直径在600~700 nm,Bi_(20)TiO_(32)可以在纳米纤维表面均匀负载,复合纳米纤维膜对可见光具有明显的响应性,对异丙隆具有很好的光催化降解效果,其中光催化剂质量分数为25.7%的样品S3对异丙隆的降解率最高可达到87%。这一研究表明,通过同轴静电纺丝法将光催化剂负载于有机纳米纤维表面,可以保持光催化剂原有光催化效果,是实现光催化剂固定化一条较好的途径。     

同轴静电纺丝再经两步后处理制备PAN基中空碳纤维

采用聚丙烯腈(PAN)溶液作为壳层,甲基硅油作为芯层,利用同轴静电纺丝技术制备出外径为3μm的同轴PAN复合纤维,经过预氧化和炭化后可以制得直径约为1μm的中空碳纤维.采用扫描电镜(SEM)观察中空纤维形貌.傅立叶红外光谱分析仪(FTIR)表征了热处理前后纤维成分变化.分析了同轴射流结构、芯液/壳液流速比Vin/Vout对中空结构的影响.研究表明,同轴内针尖伸出外针尖的距离Zp是影响同轴射流形成的主要因素,伸出长度Zp约为外针孔半径rout的1/2时得到同轴射流,Zp>0.7rout时从冠状锥体周围产生许多射流,不能在锥顶部形成同轴射流.芯液/壳液流速比Vin/Vout对中空结构的形成有较大影响,当Vin/Vout=0.5时得到多孔纤维,增大芯液流速,当Vin/Vout=1时得到中空纤维,继续增大Vin/Vout=2时得不到同轴射流.     

羟基磷灰石/丝素蛋白复合纤维的制备及其矿化研究

在以静电纺丝法制备羟基磷灰石(HAP)/丝素蛋白(SF)复合纤维的前提下, 采用同轴共纺法获得了以HAP为“芯”、SF为“皮”的双组分电纺纤维(电纺膜), 并通过扫描和透射电镜、红外光谱以及X射线衍射等手段对电纺纤维进行了表征. 结果表明, HAP均存在于上述两种方法制备的纳米纤维中, 但同轴共纺法不仅可以避免HAP/SF共混电纺时pH值对丝素蛋白结构的影响, 并且能大大提高电纺膜中HAP的含量. 同时, 我们还分别以SF纤维、HAP/SF复合纤维和HAP/SF“皮-芯”纤维作为有机基质, 对羟基磷灰石在其上的矿化过程进行了探索, 结果表明含较多羟基磷灰石的HAP/SF“皮-芯”纤维更有利于矿化的进行.     

同轴电纺制备刚性多糖纳米纤维膜

将壳聚糖、海藻酸钠或透明质酸配制成水溶液,聚氧化乙烯(PEO)溶解在二甲基甲酰胺(DMF)/H2O 混合溶剂中,以上述两溶液分别作为内、外纺丝液进行同轴电纺制备成纤维膜,进而利用适当溶剂除去 PEO 外壳,得到纯多糖纳米纤维膜.纤维结构通过 TEM、SEM 进行表征.结果表明:同轴电纺可一步制得外壳为 PEO、内核为刚性多糖的核壳纳米纤维,纤维外壳 PEO 组分可以用氯仿萃取除去;与单轴电纺法制得的刚性多糖纤维相比,同轴电纺可以保持最终纤维的结构完整性.     

静电纺丝制备铁(Ⅱ)/聚丙烯腈复合纳米纤维及其应用于吸附铬(Ⅵ)

利用静电纺丝技术制备了铁(Ⅱ)/聚丙烯腈[Fe(Ⅱ)/PAN]复合纳米纤维,用于吸附检测溶液中的铬(Ⅵ)。SEM及BET分析可知,纤维形态结构均匀,直径大约为153nm,比表面积为14.0m2·g-1。Fe(Ⅱ)/PAN复合纳米纤维表面携带的PAN…Fe(Ⅱ)(OH)+官能团能快速吸附去除溶液中的铬(Ⅵ),并将其还原为铬(Ⅲ)。根据吸附等温线模型分析,Langmuir模型更适合本体系,最大吸附量为5.40mg·g-1。在优化的试验条件下,97%的铬(Ⅵ)可被从溶液中去除。     

静电纺羟基磷灰石/明胶微纳复合纤维

本文从仿生角度出发,模拟细胞外基质独特结构,采用静电纺丝法成功制备出HA均匀分布的HA/Gelatin复合纤维。根据影响静电纺丝的主要因素,分别考察了聚合物浓度、无机物含量、溶剂浓度、电纺电压等因素对纤维形貌和结构的影响。研究结果表明:聚合物浓度是制备复合纤维的首要影响因素,影响复合纤维的直径;无机物的添加使聚合物中的氢键减少,降低了电纺液的粘度,影响复合纤维中珠状物的形成;制备分布均匀的电纺纤维,溶剂起很大的作用,影响纤维的粘联;电纺电压增大使电场力过大,聚合物被强力拉伸,单根纤维出现卷曲。     

静电纺聚丙烯腈纳米纤维晶态结构及取向的形成

采用新型流动水浴收集方式制备出连续单向排列的静电纺聚丙烯腈(PAN)纳米初生纤维,收集静电纺丝不同阶段的静电纺PAN纳米纤维,并在热水中进行后牵伸,使其伸长至原长的2倍、3倍.通过扫描电子显微镜(SEM)、广角X射线衍射(WAXD)等方法对静电纺丝过程不同阶段的PAN纳米纤维的形貌、直径、致密性、晶态结构及取向进行了表征.研究表明,(1)在静电纺丝过程中PAN纺丝液射流受到牵伸作用,静电纺PAN纳米纤维的晶态结构形成并逐渐完善.纳米纤维的直径随着静电纺丝过程逐渐减小(从664 nm减小至353 nm),结晶度从42.55％增加至47.76％,晶区取向由37.48％提高至43.93％.纳米纤维致密性也逐渐提高(密度由1.1917 g/cm3增加至1.1943 g/cm3).(2)静电纺丝过程进入PAN射流溶剂含量较低的阶段后,继续通过静电纺丝过程提高纳米初生纤维晶态结构及取向的效果很有限,而通过热水后牵伸过程可进一步使晶态结构及取向得到有效果的完善.研究同时发现,静电纺初生纤维的晶态结构及取向与其在热水牵伸过程中的进一步完善具有相关性.     

Degradation behaviour of PCL/PEO/PCL and PCL/PEO block copolymers under controlled hydrolytic,enzymatic and composting conditions

Short-term hydrolytic and enzymatic degradation of poly(ε-caprolactone) (PCL), one series of triblock (PCL/PEO/PCL) and the other of diblock (PCL/PEO) copolymers, with a low content of hydrophilic PEO segments is presented. The effect of the introduction of PEO as the central or lateral segment in the PCL chain on copolymer hydrolysis and biodegradation properties was investigated. FTIR results revealed higher hydrolytic degradation susceptibility of diblock copolymers due to a higher hydrophilicity compared to PCL and triblock copolymers. Enzymatic degradation was tested using cell-free extracts of Pseudomonas aeruginosa PAO1, for two weeks by following the weight loss, changes in surface roughness, and changes in carbonyl and crystallinity index. The results confirmed that all samples underwent enzymatic degradation through surface erosion which was accompanied with a decrease in molecular weights. Diblock copolymers showed significantly higher weight loss and decrease in molecular weight in comparison to PCL itself and triblock copolymers. AFM analysis confirmed significant surface erosion and increase in RMS values. In addition, biodegradation of polymer films was tested in compost model system at 37 °C, where an effective degradation of block copolymers was observed.     

PEO／PVP共混体系结晶行为

本文用WAXD、PLM、DSC方法研究了聚氧化乙烯(PEO)/聚乙烯基吡咯烷酮(PVP)共混体系的结晶行为,探索了两组分聚合物间相互作用及体系结晶度与非晶组分含量的关系。DSC研究表明PEO/PVP共混体系具有两个玻璃化转变温度,分别是纯组分的T_g,无相容性。应用Avrami和LH方程对其动力学参数进行了研究。偏光显微镜观察了共混物结构形态。     

PEO分子量对POM/PEO晶/晶共混物溶液结晶的影响

以六氟异丙醇(HFIP)为聚甲醛(POM)与聚氧化乙烯(PEO)的共溶剂,通过溶液结晶研究了PEO分子量对POM/PEO 50/50晶/晶共混物结晶行为及结晶形态的影响。结果表明,PEO分子量越小,POM与PEO在结晶过程中相互干扰越大。当PEO分子量为4×103时,共混物中POM形成部分不完善晶体,出现明显的熔融双峰。SEM结果表明:含不同分子量PEO的共混晶体均无明显相分离,且低分子量PEO的共混物更易形成规整球晶,认为通过溶液结晶,POM/PEO 50/50共混物中POM与PEO形成了晶体相互穿插的结晶结构。     

结晶-非晶共混体系的结晶行为研究——PEO/PMMA与PEO/PVA共混物

用DSC和傅里叶红外(FTIR)光谱表征PEO/PMMA和PEO/PVA共混体系的结晶行为。发现PEO/PVA体系的结晶度与其组成的变化是一致的;而PEO/PMMA体系的结晶度随非晶组分增加而下降的速度,从与组成变化一致到比后者快,但又随时间而改变。对此结晶/非晶共混体系的结晶度随组成和时间而变化的现象,可用体系的玻璃化转变温度(T_g)来解释。     

Proton NMR investigation of the local dynamics of PEO in PEO/PMMA blends

Longitudinal relaxation of proton magnetisation was used to characterize the molecular motions of PEO chains in compatible PEO (hydrogenated)/PMMA (deuterated) blends. Both the temperature and the PEO concentration, Φ, were varied. A maximum in the spin–lattice relaxation rate was observed and its properties were analyzed as a function of Φ. For Φ ≤ 0.50, the maximum is observed below the glass transition temperature of the blend; this shows that PEO chains dispersed in a matrix of PMMA remain highly mobile on a local scale even below T_g(Φ). A frequency–temperature correspondence procedure, applied to the measurements performed at two Larmor frequencies, 32 and 60 MHz, leads to a characteristic correlation time for PEO molecular motions. Its temperature dependence obeys a WLF free volume relation above the glass transition of the blends. The PEO free volume fraction and its thermal expansion are strongly reduced by the presence of the PMMA chains. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 1095–1105, 1997     

Structure and properties of keratin/PEO blend nanofibres

Keratin proteins are the major component of hair, feathers, wool and horns and represent an important source of renewable raw materials for many applications. Regenerated keratin has useful properties such as biocompatibility and biodegradability. Moreover, keratin materials can absorb heavy metal ions, formaldehyde and other VOCs. In this work, regenerated keratin was blended with aqueous solutions of poly(ethylene oxide) (PEO) in different proportion in order to improve its processability. Keratin/PEO nanofibres were produced by electrospinning the blend aqueous solutions. The chemical, physical and rheological characteristics of the blend solutions were correlated with morphology, structural, thermal and mechanical properties of the electrospun mats.     

The Electrochemical Behavior of PPV/PEO Blend

Light-emittingelectrochemicalcellisanewpromisingdeviceforlarge-areadisplay'.Theelectrochemicaldopinginthepolymerblendofpoly(ethyleneoxide)(PEO)andpoly(l,4-phenylenevinylene)(PPV)usedintheLECplaysaveryimpo~roleinitselectroluminescence.TheaimofthisinvestigationistounderstandiftheadditionofPEOaffectstheelectrochemicalbehaviorofPPVandtheeffectsofdopantsonsuchablendsystem.Accordingtotheprocessesreportedintheliteramresl',wepreparedthepolymerblendonaPtelectrodewhichwasusedastheworkingelectrode…     

PMMA-PEO共混体系的辐射交联

<正> 聚甲基丙烯酸甲酯(PMMA)是典型的辐射裂解型聚合物。经辐照后,PMMA主链发生无规断裂。在聚合物共混体系中,PMMA是否能发生交联,这是辐射化学中一个非常重要的研究课题之一,也是一项探索性工作。 PMMA-PEO共混体系是可以分子水平共溶的体系。本文试图将共混体系的相容性与共混体系中的裂解型聚合物的辐射效应联系起来,讨论PMMA-PEO共混体系的辐射交联。     

Effect of hydrotropes on the solution behavior of PEO/PPO/PEO block copolymer L62 in aqueous solutions

Effect of hydrotropes viz. sodium benzene sulfonate (NaBS), sodium toluene sulfonate (NaTS) and sodium xylene sulfonate (NaXS) on the micellization, phase behavior and structure of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymer L62 in aqueous solution was studied by surface tension, dye spectral, cloud point and small angle neutron scattering measurements. The addition of hydrotropes increased the critical micelle concentration (CMC) of L62 which appears to be logistic as the added hydrotrope enhances the solubility of PPO moiety (and PEO) making it behave like a more hydrophilic block copolymer that would micellize at high copolymer concentration. Partial phase diagram of L62 in water shows two cloud point (CP) in the concentration range (0-10 wt.%). Addition of hydrotropes shifts the L62 concentration range showing double cloud points at lower side of concentration; sodium xylene sulfonate (NaXS) being more effective. SANS data for L62 in the presence of 0.4 and 0.8 M NaXS at temperatures <30 °C showed unimers which are fully dissolved Gaussian chains. The unimer-to-micelle transition takes place when temperature is increased. It is found that SANS data for L62 in the presence of 0.4 M NaXS (40 and 50 °C) and 0.8 M NaXS (45 and 50 °C) correspond to ellipsoidal structure of micelles.     

Enhanced orientation of PEO polymer chains induced by nanoclays in electrospun PEO/clay composite nanofibers

Polymer fibers composed of poly(ethylene oxide) (PEO) and nanoclay were fabricated by electrospinning. The morphology of the composite nanofibers was characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM), which showed aligned nanoclays in the fibers. Polarized Fourier transform infrared (FT-IR) spectroscopy revealed that the PEO chains in the composite fibers exhibit a higher degree of orientation than that in PEO nanofibers containing no nanoclay. It is believed that spatial confinement is present in the electrospun nanofibers, which results in the enforcement of the mutual restriction. The anisotropic hierarchical nanostructure may have potential applications in optics, mechanical materials, and biomedical materials for cell culture.