聚乙烯-乙烯醇/TiO2共混非织造布的制备及其表征

通过高压静电纺丝技术,以异丙醇/水为混合溶剂,通过TiO2共混改性,制备了不同二氧化钛含量的聚乙烯-乙烯醇(EVOH)/二氧化钛(TiO2)非织造布,通过扫描电子显微镜、X-射线衍射(XRD)对其微观形貌、结晶性能进行了研究,并分析了相对面电阻和吸碱率与TiO2共混量的关系。结果表明:经TiO2共混改性后,纤维中有白色团状突起出现,有实心纤维和空心纤维两种形貌;XRD分析表明,随着TiO2含量的增加,EVOH/TiO2非织造布的结晶度越来越低;非织造隔膜的吸碱率最大可达到950%。     

明胶改性聚乳酸纤维性能的研究

用己二胺和戊二醛处理聚乳酸(PLA)纤维,在纤维表面引入醛基,接枝明胶后获得表面亲水改性的PLA纤维。接枝明胶在改善纤维亲水性的同时保持了纤维的拉伸强度,还提高了纤维在碱性溶液中的湿热稳定性。经戊二醛交联,PLA纤维表面亲水性降低,水分难与纤维表面接触,热碱溶液处理后纤维力学损伤程度降低,进一步提高了PLA纤维的湿热稳定性。     

松木纤维表面超支化接枝改性及其对PP复合材料性能的影响

为了改善松木纤维与聚丙烯(PP)之间的界面结合性能,采用接枝改性技术在纤维表面逐步接枝超支化聚酰胺,并用接枝改性后的纤维与PP及相容剂熔融共混制备复合材料。采用傅里叶变换红外光谱及热重分析对改性前后纤维的官能团及热性能进行了分析表征,并对纤维增强PP复合材料的拉伸强度进行了测定。结果表明,经超支化聚酰胺改性后,纤维表面成功引入了大量的氨基基团。经1.0代超支化聚酰胺接枝改性后,纤维的耐热性有所增加,但经2.0及3.0代超支化聚酰胺接枝改性后,纤维的耐热性均有所下降。经超支化聚酰胺接枝改性后,纤维增强PP复合材料的拉伸强度均有所提高,其中2.0代超支化聚酰胺改性的纤维增强PP复合材料拉伸强度最高。对于未改性或KH–550改性的纤维,其目数为20目时的复合材料拉伸强度较目数为40目的高,但超支化聚酰胺接枝改性的纤维增强复合材料拉伸强度随纤维尺寸的变化情况与此相反。     

聚酯纤维非织造布紫外光表面接枝改性研究

以PET纤维非织造布为处理对象，研究了紫外接枝过程中不同单体、引发剂、溶剂对接枝处理后的非织造布与改性苯丙胶乳粘接性能的影响。发现以AM为接枝单体，安息香为光引发剂，水和丙酮为混合剂时效果最好。并且通过正交设计实验方法，找出最佳处理条件，经这个最佳条件处理后的非织造布浸渍改性苯丙胶乳，然后固化，测得其横向拉伸强力从未处理前的47N增加到119．28N，效果显著。     

聚多巴胺改性静电纺EVOH–SO_3Li薄膜的热力性能

由静电纺丝技术制备的EVOH–SO_3Li纳米纤维薄膜的力学性能不高,为了改善薄膜的力学性能,采用多巴胺对EVOH–SO_3Li纳米纤维膜进行改性。通过宏观形貌观察、扫描电子显微镜、傅立叶变换红外光谱分析这三种测试方法相结合,表明多巴胺粘附在纳米纤维上,并在纤维膜上进行自聚形成聚多巴胺(PDA)。热失重分析结果表明,热失重为10%时PDA改性后的隔膜较未改性的EVOH–SO_3Li纯膜提高了67℃。拉伸性能测试结果表明,浸泡浓度为0.015 mol/L时,PDA改性后的隔膜拉伸强度比纯膜提高了11.89 MPa。PDA改性后薄膜的孔隙率有所下降但吸液率提升明显,最高达到了480%。     

剑麻纤维的溶胶–凝胶技术改性

通过溶胶–凝胶技术以正硅酸乙酯作为溶胶前驱体对剑麻纤维进行改性,采用傅里叶变换红外光谱(FTIR)、热重(TG)分析、X射线光电子能谱(XPS)分析以及单根纤维拉伸性能测试对改性剑麻纤维进行表征。FTIR和XPS测试结果表明,SiO_2凝胶成功引入剑麻纤维中;TG分析结果表明,经过溶胶–凝胶技术改性后,剑麻纤维的起始热分解温度变化很小,仅提高约0.5℃,但失重率明显降低;拉伸性能测试结果表明,溶胶–凝胶技术改性剑麻纤维的拉伸强度高于未改性的纤维,且剑麻纤维的吸湿率越高,单根纤维的拉伸强度越高,当纤维吸湿率为22.7%时,其拉伸强度较未改性纤维提高了29.21%,较KH550改性纤维提高了7.84%。     

EVOH基交联离子聚合物的制备及其表征

以聚乙烯-乙烯醇(EVOH)为基体,通过化学修饰,在EVOH主链上引入磺酸基来控制产物的离子交换当量(IEC),利用缩醛反应进行交联改性来控制产物水溶性,进而合成出具有高IEC值和低水溶性的交联离子聚合物.反应后经滴定测定出产物的磺化度和IEC值,由红外光谱(FT-IR)表征产物的化学结构.结果表明,1260cm-1附近磺酸的S=O伸缩振动吸收峰的存在说明了磺化产物的存在;热重分析(TGA)表明,经交联改性后的离子聚合物,其热分解温度由397℃上升到439℃,耐热性明显提高.     

芳纶APMOC纤维辐照处理研究

通过γ－射线辐照处理技术对芳纶 APMOC纤维进行改性。结果表明,经过辐照剂量500kGy辐照后,APMOC纤维产生了辐照交联反应,其复丝拉伸强度和复合材料的横向拉伸强度明显提高。     

戊二醛交联改性鼠尾I型胶原纤维的结构与性能研究

以自制的鼠尾I型胶原为原料,经湿法纺丝制备胶原纤维,采用戊二醛蒸气对胶原纤维进行交联改性处理,对交联改性前后纤维的结构和性能进行了表征。结果表明:经戊二醛交联改性处理后,胶原纤维的断裂强度得到提高,与未交联胶原纤维相比,交联处理20 min的胶原纤维断裂强度提高了15.8%;交联改性胶原纤维抗水性明显提高,交联20 min后,吸水率明显减小且趋于稳定;戊二醛在胶原纤维表面发生了化学反应,交联改性胶原纤维的三股螺旋结构的稳定性和热稳定性提高。     

聚丙烯纤维/表面改性黄麻纤维复合膜的制备及性能

以聚丙烯(PP)纤维为基体,经碱、偶联剂表面改性处理后的黄麻纤维为第二组分,采用非织造-模压工艺制备了PP纤维/表面改性黄麻纤维复合膜,探讨了经表面改性处理后的黄麻纤维含量对复合膜的力学性能、吸水性能以及复合膜的断面形貌的影响。结果表明:随着黄麻纤维含量的增加,复合膜的拉伸强度呈先增大后减小趋势,但变化不明显,当黄麻纤维质量分数为10%时,拉伸强度达到最大为60.5MPa,复合膜的拉伸模量、弯曲强度、弯曲模量也呈先增大后减小趋势,当黄麻纤维质量分数为30%时,复合膜力学性能最优,其拉伸模量、弯曲强度、弯曲模量分别为6.4 GPa,80.7MPa,5.0 GPa;复合膜的吸水率(W)随黄麻纤维含量的增加而增大,当黄麻纤维质量分数为40%时,复合膜的W最大为6.6%;当复合膜中黄麻纤维质量分数小于等于30%时,PP纤维与黄麻纤维之间界面粘合良好,黄麻纤维与PP纤维紧密相连,相互交叉形成网状结构。     

高压静电纺丝法制备EVOH/TiO2无纺布

采用高压静电纺丝技术，以异丙醇／水为混合溶剂，制备了聚乙烯-乙烯醇（EVOH），二氧化钛（TiO2）无纺布；通过引描电子显微镜、差示扫描量热仪及热失重仪对其微观形貌、热性能进行了研究分析；结果表明：经TiO2掺杂改性后，尤纺市的纤维商径减小，孔径降低，无纺布的结晶度降低，熔点变化不大，耐热性下降。     

聚乙烯-乙烯醇无纺布制备工艺及性能研究

以异丙醇／水为纺丝溶剂,采用高压静电纺丝技术制备了聚乙烯-乙烯醇（EVOH）无纺布,通过考察纺丝混合溶剂配比、溶液浓度等工艺,对EVOH无纺布微观形貌和力学性能进行了研究,并获得了聚乙烯-乙烯醇无纺布的最佳制备工艺。结果表明,当纺丝液复合溶剂异丙酗水配比为70／30（v／v）、纺丝液浓度为10％（w／v）时制得的EVOH无纺布的力学性能较其它溶液体系的无纺布性能较高,其拉伸强度和断裂伸长率分别为53．7MPa和57．5％。     

Development of bacterial cellulose nanowhiskers reinforced EVOH composites by electrospinning

In the current study, hybrid electrospun ethylene vinyl alcohol (EVOH) fibers reinforced with bacterial cellulose nanowhiskers (BCNW) were developed and characterized. Additionally, electrospinning was suggested as a method for the incorporation of well‐dispersed BCNW into an EVOH matrix by melt compounding. With the aim of maximizing the BCNW's loading in the electrospun fibers, an optimized method was applied for generating fibers from solutions containing up to 40 wt % BCNW. As demonstrated by FTIR spectroscopy, it was possible to incorporate BCNW concentrations up to ～ 24 wt %, although a complete incorporation of the nanofiller into the fibers was only achieved with solutions containing up to 20 wt % of the filler, DSC analyses suggested that the incorporation of the nanofiller reduced the crystallinity of the as‐obtained EVOH fibers and produced an increase in the glass transition temperature of these during the second heating run. Thermogravimetric analyses showed that even though EVOH protects the nanowhiskers from thermal degradation, the electrospun hybrid fibers present a relatively lower thermal stability than the pure EVOH fibers. FTIR analyses of the samples subjected to different thermal treatments confirmed that the stiffening effect observed by DSC only occurs after melting of the EVOH phase and is cooperative with a partial acid chemical development in the BCNW, which promotes strong chemical interactions between the polymeric matrix and the nanofiller. Finally, the hybrid electrospun fibers were incorporated into pure EVOH by melt compounding to produce composite films. This methodology showed higher stability and dispersion of the BCNW than direct addition of the freeze‐dried nanofiller to EVOH. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

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     

Effect of Thermoplastic Starch and Photocrosslinking on the Properties and Morphology of Electrospun Poly(ethylene-co-vinyl alcohol) Mats

Nonwoven fibrous mats of poly(ethylene-co-vinyl alcohol) (EVOH) and thermoplastic starch (TPS) blends were successfully prepared through the electrospinning technique using a mixed solvent system of isopropyl alcohol and water. The influence of TPS on the morphology and structure of the fibrous mats was investigated using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy. The addition of TPS to EVOH resulted in beaded electrospun fibers. The SEM images revealed decreasing average width of the blend fibers and increasing quantity of beads with an increased TPS content. EVOH/TPS fibers mats irradiated under ultraviolet light using sodium benzoate as a photosensitizer were also prepared. The size and number of beads were diminished in the photocrosslinked EVOH/TPS fiber mats. The as-spun and crosslinked EVOH/TPS fiber mats exhibit a superior fluid uptake ability (with 20 wt% of TPS) and superior barrier properties (with 20 and 40 wt% of TPS) in comparison to those observed in neat electrospun EVOH mats. These properties are of particular interest for use in dressing materials for the medical industry and for use in multilayer plastic fuel tanks for the automotive industry, respectively. POLYM. ENG. SCI., 60:474–480, 2020. © 2019 Society of Plastics Engineers     

Crosslinking reactions of oxidized cellulose fiber. I. Reactions between dialdehyde cellulose and multifunctional amines on lyocell fabric

Fibrillation‐controlled lyocell fibers were developed by crosslinking reactions between dialdehyde cellulose (DAC) and multifunctional amines. DAC lyocell fibers were manufactured by partial oxidation with sodium metaperiodate and were successfully crosslinked with two multifunctional amines by Schiff‐base formation. The amorphous regions and the char formations, which were characterized by differential scanning calorimetry and thermogravimetric analysis, increased with the degree of oxidation. After the crosslinking reactions, an increase in the amorphous regions also appeared, whereas the thermal stability was somewhat improved by the chain crosslinking. These results were in good agreement with viscosity‐average degree of polymerization values in that they diminished with oxidation level and increased with the crosslinking reactions. The water retention value and moisture regain value decreased with the oxidation and crosslinking levels, which implied that the swellability of fibers and the water absorbency in characteristic sites decreased with them. The increase in the dry crease recovery angle also confirmed the presence of hemiacetal crosslinks in the DAC and amine crosslinks between the DAC and the amines. The fibrillation grade of the crosslinked fibers diminished with oxidation level and the amine concentration. In particular, the fibrillation properties of the crosslinked fibers with 4‐hydroxy‐2,4,6‐triaminopyrimidine sulfate salt were more easily controlled than those of the crosslinked fibers with 2,4,6‐triamino‐1,3,5‐triazine. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Mechanical and thermal properties of acrylic fibers crosslinked with disulfonyl azides

A novel method for the crosslinking of acrylic fibers was devised, which uses disulfonyl azides as crosslinking agents. This is a fiber‐finishing process in which 1,6‐hexanedisulfonyl azide, 1,3‐benzenedisulfonyl azide, 4,4‐biphenyldisulfonyl azide, 1,5‐naphthalenedisulfonyl azide, and 2,6‐naphthalenedisulfonyl azide were applied to an acrylic fiber (Courtelle) and thermally treated to bring about crosslinking. A study was made of the mechanical and thermal properties of the crosslinked fibers and of the abrasion and pilling performance of the associated fabrics. Crosslinking brought about significant improvements in the initial modulus, resistance to abrasion, pilling performance, and thermal stability of the fibers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1309–1319, 2002; DOI 10.1002/app.2349     

Fabricating novel thermal crosslinked ultrafine fibers via electrospinning

In this article, we report the preparation of a kind of novel crosslinked ultrafine fiber by electrospinning of unsaturated polyester macromonomers (UPM) and subsequent thermal crosslinking. The UPM is prepared via a two‐step reaction with poly(2‐methyl‐1,3‐propyleneadipate) diol terminated (PMPA), isophorone‐diisocyanate (IPDI) and 2‐hydroxyethyl methacrylate (HEMA). Poly(3‐hydroxyl‐butyrate‐co‐3‐hydroxylvalerate) (PHBV) is chosen to improve the processability of the UPM. UPM/PHBV blend ultrafine fibers are successfully electrospun with a proper mass ratio of UPM to PHBV in dichloromethane solution. The fibers are thermally crosslinked after electrospinning. Measurement results indicate that the average diameter of the fibers is about 1 μm and the crosslinked fibers have good solvent‐stability and thermal‐stability. This novel fiber has potential applications in filtration and protective coating. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 107:2142–2149, 2008     

Loop strength of spun collagen fibers

The effects of gultaraldehyde (GA) crosslinking, basic chromium sulfate (Cr) tanning, and thermal treatments on the loop strength of spun collagen fibers were studied. The loop test have been carried out using a piano wire as a model loop. The promotion of GA crosslinking led a significant decrease of the strength and elongation at break. On the other hand, the promotion of Cr tanning gave no change. These properties decreased with an increasing shear stress at bending region of loop. The improvement of these mechanical properties were realized by thermal treatments of both GA crosslinked and Cr tanned fibers. The thermal treatment temperature showed the maximum effect at 100°C. However, there was no effect of thermal treatment for the noncrosslinked fibers. The fracture morphology of Cr tanned fibers is characterized by longitudinal splitting along the fiber axis in the bending region, although the fracture morphology of noncrosslinked and GA crosslinked fibers can be characterized by transverse fracture. © 1996 John Wiley & Sons, Inc.