添加不同物质的聚乙烯醇/海藻酸钠静电纺丝研究

分别添加少量NaCl、乙酸、表面活性剂十二烷基硫酸钠(SDS),研究少量添加物对海藻酸钠/聚乙烯醇(PVA)溶液性质和静电纺纤维的影响,并初步探讨了溶液静电纺丝机制。结果表明:NaCl改变了溶液的电导率和黏度,乙酸降低了溶液的黏度、提高了溶剂挥发性,SDS降低了溶液的表面张力;适量的添加物可使纤维形貌得到改善;添加物对电纺纤维化学结构无本质影响;无机盐离子加剧了纤维拉伸作用,结晶性有所提高;处于泰勒锥处液滴表面受到静电排斥力、表面张力、同种聚合物分子间的氢键作用力、不同聚合物分子间的氢键作用力以及聚合物同水等溶剂形成的氢键作用力。     

再生丝素蛋白/聚乙烯醇共混纳米纤维的静电纺丝研究

以静电纺丝方法制备再生丝素蛋白/聚乙烯醇共混纳米纤维。研究了共混配比、溶液浓度、添加剂含量及电纺电压、喷丝距离等因素对纤维成形及纤维有关性能的影响。研究表明:与聚乙烯醇共混后再生丝素纤维的柔韧性有一定改善,适当增加PVA在共混物中的含量、提高纺丝液浓度以及纺丝电压有利于改善共混溶液的可纺性。另外,加入丙三醇虽可使纤维直径的均匀性有所提高,但却不利于纤维成形。     

维生素对聚乙烯醇溶液静电纺丝性能的影响

将维生素(VC)溶解在质量分数8%的聚乙烯醇(PVA)水溶液中,通过静电纺丝制得PVA/VC共混纳米纤维。分析了VC含量对溶液性能及静电纺丝速度的影响;测试了纤维的形貌结构及力学性能。结果表明:PVA/VC共混溶液属于切力变稀流体;当PVA/VC质量比为100/10或100/20时,共混溶液的电导率和静电纺丝速度较纯PVA溶液明显提高,制得的纳米纤维表面光滑,粗细均匀;与纯PVA纳米纤维比较,其平均直径和拉伸强度降低,断裂伸长率提高。     

丝素-聚乙烯醇共混溶液静电纺丝及其含银纳米纤维形态研究

研究了不同丝素-聚乙烯醇（SF-PVA）配比的共混溶液和加入硝酸银的丝素-聚乙烯醇（SF-PVA）共混溶液的静电纺丝,利用扫描电镜观察纤维的形态变化。结果表明：在丝素（SF）或聚乙烯醇（PVA）占绝大部分时,整个体系溶解性保持相对稳定,容易形成比较均一的溶液,且纺丝后纤维形态比较均匀、规则;而在两组分含量接近时整个体系的溶解性能较差,不易形成比较均一的溶液,表现为溶液粘度的显著增大,纺丝后纤维不均匀、不规则。笔者选用SF/PVA=1：9（质量比）的共混纺丝液加入硝酸银,随着硝酸银在溶液中含量的增加,溶液电导率会明显增加,纤维的直径明显下降;但随着电导率的增大,纤维中珠状物会增多,纤维均一性也变差。     

静电纺丝法制备聚乙烯醇纳米纤维膜及其交联处理

用化学方法和物理方法对聚乙烯醇(PVA)纳米纤维膜进行交联处理,并且用SEM、DSC和XRD分别对不同的纳米纤维膜样品进行表征。结果表明:煅烧处理的PVA纳米纤维膜的结晶度提高,抗溶解性能良好。     

海藻酸钠/聚乙烯醇溶液的性能及静电纺丝

将质量分数为2%的海藻酸钠(SA)与质量分数为8%的聚乙烯醇(PVA)按一定体积比混合后进 行静电纺丝,研究了SA与PVA溶液的相容性及SA/PVA共混溶液性能.结果表明:SA与PVA溶液相容;随着PVA含量的增加,SA/PVA共混溶液的粘度、表面张力、电导率则降低,共混溶液的可纺性提高;静电纺丝得到的SA/PVA超细...     

PVA静电纺丝工艺优化研究

以聚乙烯醇(PVA)为原料、去离子水为溶剂,通过静电纺丝制备PVA纳米纤维膜,利用正交实验探讨静电纺丝过程中纺丝液PVA浓度、纺丝距离、纺丝电压和注射速度对PVA纳米纤维膜形貌及纤维直径的影响,得出制备纤维膜的较佳工艺条件,并分析了纺丝液PVA浓度对纤维膜的力学性能和亲水性能的影响。结果表明：随着纺丝液PVA浓度的增加,PVA纤维的直径逐步变小,直径分布变窄;当纺丝液PVA质量分数为7%、纺丝电压为14 kV、纺丝距离为14 cm、注射速度为0.5 mL/h时,纤维膜的纤维直径最小,为203 nm;正交实验中PVA浓度、纺丝电压、纺丝距离、注射速度4个因素的极差值分别为87.00,49.67,18.33,11.67;纺丝液PVA质量分数从5%增加到7%,纤维膜的断裂强度从2.21 MPa提高至2.81 MPa,断裂伸长率从31.63%提高至56.39%,水接触角从37.7°提高至48.7°。     

静电纺丝制备纳米级纤维的研究

首先介绍了静电纺丝制备纳米纤维的原理及其影响因素,然后归纳、总结了当前国内外静电纺丝制备纳米纤维的研究内容,并对今后的研究提出了建设.     

热熔处理对壳聚糖/聚乙烯醇静电纺丝纳米纤维膜力学性能的影响

静电纺丝方法制备的纳米纤维膜的强度主要来源于其纤维间的缠接,因此强度较低。对壳聚糖(CS)/聚乙烯醇(PVA)纳米纤维膜采用了热熔处理的方法,使纳米纤维之间发生热熔,研究了热熔处理对纳米纤维微观结构、力学性能和亲水性能的影响。扫描电镜结果显示,热熔处理后的纳米纤维间出现熔接的现象,同时伴有部分纤维的断裂。力学性能测试表明,热熔处理能够提高纳米纤维膜的力学性能,热熔温度为100℃时,纳米纤维膜的力学性能提升最高。水接触角测试表明,热熔处理会使得纤维结构更为致密,导致其水接触角增大;XRD和FT-IR测试表明,热熔处理在增大纳米纤维膜结晶性的同时,未明显改变纳米纤维膜的化学结构。     

Reactive electrospinning of poly(vinyl alcohol) nanofibers

We aim to couple the electrospinning in‐line with solution chemistry to fabricate novel crosslinked polymer nanofibers. Poly(vinyl alcohol) (PVA) was used as a model polymer due to its high amount of hydroxyl groups. To obtain ideal parameters for electrospinning, pure PVA was explored primarily. To gain crosslinked fibers, PVA was first crosslinked partially with glutaraldehyde (GA) followed by transferring this precursor to a long hot tube which was used as reactor and then electrospun right before gelation. The preheating time and tube‐passing time were determined with viscometer and rheometer. The reactive as‐spun fibers could maintain their original morphology after water immersion due to their high crosslinking degree. The thermal stability and mechanical property of reactive as‐spun fibers were improved drastically compared with pure and GA vapor crosslinked PVA fibers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effects of the tacticities of poly(vinyl alcohol) on the structure and morphology of poly(vinyl alcohol) nanowebs prepared by electrospinning

The effects of tacticities on the characteristics of poly(vinyl alcohol) (PVA) nanowebs prepared by an electrospinning technique were investigated. PVA webs composed of uniform nanofibers with syndiotactic dyad (s‐dyad) contents of 53.5 and 57.3% were successfully obtained with electrospinning. By changing processing parameters such as the initial polymer concentration, applied voltage, and tip‐to‐collector distance, we found suitable conditions for forming PVA webs with uniform nanofibers. PVAs of higher s‐dyad contents were prepared at a lower solution concentration and at a higher applied voltage because of the easy formation of syndiotactic PVA chain entanglements at a very low polymer concentration. The average diameter of the nanofibers in a PVA web with the higher s‐dyad content of 57.3% (ca. 240 nm) was thinner than that of the nanofibers in a PVA web with the lowers‐dyad content of 53.5% (ca. 270 nm). In addition, the crystallinity and thermal stability were greatly increased with an increase in the s‐dyad content. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

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。     

Preparation and characterization of graphene oxide/poly(vinyl alcohol) composite nanofibers via electrospinning

Graphene oxide (GO) was well dispersed in poly(vinyl alcohol) (PVA) diluted aqueous solution, and then the mixture was electrospun into GO/PVA composite nanofibers. Electron microscopy and Raman spectroscopy on the as‐prepared and calcined samples confirm the uniform distribution of GO sheets in the nanofibers. The thermal and mechanical properties of the nanofibers vary considerably with different GO filler contents. The decomposition temperatures of the GO/PVA composite nanofiber dropped by 38–50°C compared with pure PVA. A very small loading of 0.02 wt % GO increases the tensile strength of the nanofibers by 42 times. A porous 3D structure was realized by postcalcining nanofibers in H₂. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Thermal and structural characterization of nanofibers of poly(vinyl alcohol) produced by electrospinning

Poly(vinyl alcohol) (PVOH) was obtained from the alkaline hydrolysis of poly(vinyl acetate) (PVAc). Nonwoven membranes (mats) of PVOH nanofibers were produced by electrospinning of solutions of PVOH in water with and without aluminum chloride. The concentration of the PVOH/water solution was 12.4% w/v. The morphology of the mats was analyzed by scanning electron microscopy (SEM). The thermal properties and the degree of crystallinity of the nanofibers were measured by differential scanning calorimetry (DSC); the crystal structure of the mats was evaluated by wide‐angle X‐ray diffraction. The best nanofibers were obtained by electrospinning the PVOH/water solution with aluminum chloride (45% w/v) in which an electrical field of 3.0 kV/cm was applied. It was observed that the addition of the aluminum chloride and the increase in the applied electrical field decreased the number‐average nanofibers diameters. The mats without aluminum chloride had higher melting temperatures and higher degrees of crystallinity than the mats with the salt. The crystal structure of the mats was found to be monoclinic; however, the mats were neither highly oriented nor have a high degree of crystallinity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Study of electrospinning of sodium alginate,blended solutions of sodium alginate/poly(vinyl alcohol) and sodium alginate/poly(ethylene oxide)

Alginate is an interesting natural biopolymer for many of its merits and good biological properties. This paper investigates the electrospinning of sodium alginate (NaAlg), NaAlg/PVA‐ and NaAlg/PEO‐ blended systems. It was found in this research that although NaAlg can easily be dissolved in water, the aqueous NaAlg solution could not be electrospun into ultrafine nanofibers. To overcome the poor electrospinnability of NaAlg solution, synthetic polymers such as PEO and PVA solutions were blended with NaAlg solution to improve its spinnability. The SEM images of electrospun nanofibers showed that the alginate (2%, w/v)–PVA (8%, w/v) blended system in the volume ratio of 70 : 30 and the alginate (2%, w/v)–PEO (8% w/v) blended system in the volume ratio of 50 : 50 could be electrospun into finest and uniform nanofibers with average diameters of 118.3 nm (diameter distribution, 75.8–204 nm) and 99.1 nm (diameter distribution, 71–122 nm), respectively. Rheological studies showed a strong dependence of spinnability and fiber morphology on solution viscosity and thus on the alginate‐to‐synthetic polymer (PVA or PEO) blend ratios. FTIR studies indicate that there are the hydrogen bonding interactions due to the ether oxygen of PEO (or the hydroxyl groups of PVA) and the hydroxyl groups of NaAlg. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

On the electrospinning of poly(vinyl alcohol) nanofiber mats: A revisit

Electrospinning was used to fabricate mats of poly(vinyl alcohol) (PVA; M_w = 72,000 Da, degree of hydrolysis ≈ 97.5–99.5) nanofibers from PVA solutions in reverse osmotic water. The effects of solution concentration, applied electrical potential, sonication, and collection distance on morphological appearance and diameters of the as‐spun fiber mats as well as those of the individual fibers were carefully investigated mainly by scanning electron microscopy. The effect of the distance from the center of the as‐spun fiber mat on morphological appearance and diameters of the as‐spun fibers was also investigated. The mechanical integrity of some as‐spun PVA fiber mats was also investigated. At all concentrations and applied electrical potentials investigated, the average diameters of the as‐spun PVA fibers ranged between 85 and 647 nm. The use of sonication to prepare a PVA solution caused the viscosity of the solution to decrease; hence, the observed decrease in the average diameters of the as‐spun fibers and the average diameters of the as‐spun fibers were practically the same throughout the as‐spun fiber mat. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

The influence of poly(vinyl alcohol) suspending agents on suspension poly(vinyl chloride) morphology

The requirements for PVC suspension resin have changed considerably in the last few years, so much so that few companies have products on their ranges that are more than 4 or 5 years old. The suspending agent has a crucial influence on the morphology of the resin, so the changes in resin characteristics have largely been achieved by changes in the suspending agent systems. After a brief review of the mechanism of PVC suspension polymerisation, the properties of polymers made using PVOH suspending agents are related to changes in the latter. The effect of variations in PVAc degree of hydrolysis and viscosity are related to changes in surface tension. Methods of achieving higher porosity by using low hydrolysis co-suspending agents are described. It is shown that higher bulk densities can be achieved by delayed addition of the PVOH. Levels of conjugated unsaturation and copolymer distributions are also shown to have important influences.     

Electrospinning fabrication and characterization of poly(vinyl alcohol)/montmorillonite nanofiber mats

Poly(vinyl alcohol) (PVA)/montmorillonite clay (MMT) nanofiber mats have been fabricated by the electrospinning technique. The PVA/MMT nanofiber mats were characterized by X‐ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and mechanical measurements. The study showed that the introduction of MMT results in improvement in tensile strength, and thermal stability of the PVA matrix. XRD patterns and SEM micrographs suggest the coexistence of exfoliated MMT layers over the studied MMT contents. FTIR revealed that there might be possible interaction occurred between the MMT clay and PVA matrix. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009