聚乙烯醇/淀粉复合薄膜的制备与性能研究

以聚乙烯醇(PVA)和淀粉为原料,采用流延成膜法制备了PVA/淀粉复合薄膜。通过热重分析(TGA)、扫描电子显微镜(SEM)以及力学性能测试,研究了PVA与淀粉的不同混合比例对所制备复合薄膜结构和性能的影响。结果表明:淀粉的加入降低了复合薄膜的拉伸性能,提高了其热稳定性。动态力学性能分析结果表明,淀粉能够提高复合薄膜的储能模量和刚性。     

蒙脱石有机化对PVA/蒙脱石复合薄膜的性能影响

以精制钠基蒙脱石(Na-MMT)、有机化蒙脱石(OMMT)和聚乙烯醇(PVA)为原料,通过水溶液插层-流延成膜法制备纳米复合薄膜。通过X射线衍射(XRD)、扫描电子显微镜(SEM)和热重分析(TGA)对复合材料的结构和性能进行表征,重点探讨蒙脱石有机化对PVA/MMT复合薄膜性能的影响。结果表明Na-MMT和OMMT纳米颗粒在PVA基体中均得到了良好分散;有机改性剂的存在促使PVA/MMT复合薄膜的MMT片层间距扩撑更大,但由于其与PVA相容性较差,导致有效插入MMT片层间的PVA分子较少,PVA/MMT复合薄膜的热稳定性改善效果不明显。     

有机改性LDH/PVA复合膜的制备及其保水性能研究

采用十二烷基硫酸钠(SDS)、十六烷基三甲基溴化铵(CTAB)和钛酸酯偶联剂(CS-311)三种改性剂对水滑石(LDH)进行改性后,通过溶液铸膜法制备改性LDH/聚乙烯醇(PVA)复合膜。使用扫描电子显微镜(SEM)和比表面仪(BET)对改性LDH进行表征,观察改性剂对LDH的形貌和比表面的影响。对改性LDH/PVA复合膜进行SEM、热重分析(TG)、耐水和保水性能等测试。结果表明,改性LDH的加入,使LDH/PVA复合膜的热稳定性、耐水和保水性能有一定提升,其中LDH-CTAB/PVA复合膜耐水性较未改性PVA膜提高3.2倍。     

甲酰胺与超声处理LDH/PVA复合膜的制备和性能研究

文章以甲酰胺为分散液,采用超声强化方式对LDH进行了剥离,利用剥离后的LDH和聚乙烯醇(PVA)制备复合薄膜。用透射电镜对处理前后的LDH进行了表征,用广角X-射线衍射仪、电子万能试验机和差示扫描量热仪对复合膜的结构、力学性能和热性能进行表征。结果表明:剥离后的LDH在甲酰胺中分散情况良好;剥离后的LDH对PVA的结晶有一定的促进作用,复合膜的拉伸强度和拉伸模量相对纯PVA膜有很大程度提高,提高幅度分别为78%和97%;在制备LDH/PVA复合膜过程中未引入任何插层剂,因此该工艺是一种简单且实用的获得高性能聚合物复合膜的工艺过程。     

焙烧复原法制备山梨酸和苯甲酸插层水滑石及其缓释性能研究

焙烧复原法无需有机溶剂,制备流程比较简单,条件容易控制。以水滑石(LDH)为载体,通过焙烧复原法分别将山梨酸(SA)和苯甲酸(BA)插入其层间,制备了SA-LDH和BA-LDH插层材料。采用傅里叶变换红外光谱(FT-IR)、X-射线衍射(XRD)、热重-差热分析(TG-DSC)和扫描电镜(SEM)对其结构和热稳定性进行表征,并研究在不同pH缓冲体系中的缓释性能和机理。结果表明,SA和BA阴离子成功的插入到LDH层间,分散效果得到了明显改善。SA-LDH表现出良好的缓释性能,在pH 4.4、3.4的缓冲溶液中120 min后达到释放平衡,释放量分别为431.34、389.38 mg/g。BA-LDH存在突释现象,缓释性能不佳,释放时间30 min时达到平衡,在pH 4.4、3.4的缓冲溶液中释放量为353.22、304.17 mg/g, SA和BA的释放过程符合准二级动力学方程。焙烧复原法制备的SA-LDH材料具有良好的缓释性能,在防腐保鲜类食品包装材料中的应用具有重要意义。     

纳米焦磷酸钛/聚乙烯醇复合薄膜的制备与性能研究

以浸渍提拉法制备了纳米焦磷酸钛(nano-TiP2O7)/聚乙烯醇(PVA)复合薄膜。采用紫外-可见-近红外分光光度计、热重分析仪、分光光度计、拉力试验机等手段对PVA薄膜和nano-TiP2O7/PVA复合薄膜进行性能测试。结果表明,nano-TiP2O7含量在0.5 phr及以上时,复合薄膜的抗紫外线效果明显;nano-TiP2O7含量为1.0 phr时,热稳定性最高,紫外线透射比最低为8%,其加速紫外老化60 h后的拉伸强度保持率为87.83%,断裂伸长率保持率为78.82%,均高于纯PVA薄膜。而且,不同nano-TiP2O7添加量的复合薄膜的耐水性能和保湿性能都得到增强,耐油性能良好。     

PVA/石榴皮粉复合薄膜的制备及性能研究

以聚乙烯醇(PVA)为基材、石榴皮粉为填充材料,采用溶液共混的方法制备了不同石榴皮粉含量的PVA/石榴皮粉复合薄膜。通过扫描电子显微镜(SEM)、红外光谱、紫外可见光谱、力学性能测试、水蒸气透过率测试、热重差热分析等手段考察了石榴皮粉含量对PVA复合薄膜性能的影响。结果表明:石榴皮粉与PVA相容性良好,与纯PVA薄膜相比,PVA/石榴皮粉复合薄膜的热稳定性显著增强,并表现出优异的紫外光阻隔性能,同时,随着石榴皮粉含量的增加,复合薄膜的水蒸气透过率提高,脆性增大。     

纳米二氧化钛-氧化锌改性双极膜制备与表征

在壳聚糖(CS)阴离子交换膜层中添加纳米二氧化钛-氧化锌复合半导体材料,制备了PVA-SA/TiO2-ZnO-CS双极膜(其中:PVA为聚乙烯醇;SA为海藻酸钠),并用热重分析等对其进行了表征。研究结果表明,纳米二氧化钛-氧化锌复合半导体材料较纳米氧化锌或纳米二氧化钛单一半导体材料具有更强的光催化双极膜中间界面层水解离能力,能大大降低双极膜的膜阻抗和膜电阻压降(IR降)。当电流密度为60 mA/cm2时,在高压汞灯照射下,PVA-SA/TiO2-ZnO-CS双极膜的槽电压较没有高压汞灯照射时下降了1.0 V;而PVA-SA/TiO2-CS双极膜和PVA-SA/ZnO-CS双极膜仅分别下降了0.7 V和0.6 V。此外,添加纳米二氧化钛-氧化锌复合半导体材料可提高双极膜的亲水性、热稳定性和机械性能。     

微晶纤维素/聚乙烯醇对明胶基复合薄膜性能的影响

聚乙烯醇(PVA)/明胶基材料具有良好的成膜性能和生物相容性,具有广泛的实际应用价值,是一个重要的研究对象。本研究将微晶纤维素(MCC)和PVA分别作为增强材料和共混材料添加到明胶(GL)基材中,改善明胶基复合薄膜的力学性能和阻隔性能。微晶纤维素的添加可赋予MCC/PVA/GL复合薄膜良好的理化性能和应用性能。当基材中添加质量分数5%MCC时,复合薄膜的拉伸强度由14.91 MPa提高到48.02 MPa,热降解温度提高了11.4℃,含水率降低了9.12%。同时,还延长了水蒸气通过PVA/GL薄膜的路径,降低了MCC/PVA/GL复合薄膜的水蒸气透过率。土壤包埋实验表明,MCC的加入加快了复合薄膜的生物降解性能。因此,MCC/PVA/GL复合薄膜可应用于绿色包装领域,如食品包装、药品包装、化妆品包装等。     

氟化石墨烯/水滑石改性环氧树脂胶黏剂的性能研究

采用尿素法制备CO3^2-型锌铝水滑石(ZnAlCO3-LDH),并将其与氟化石墨烯(FG)复合,制备不同质量比的FG-ZnAl-LDH,然后将其作为填料对环氧胶黏剂进行改性。通过红外光谱、X射线衍射和扫描电镜对填料进行表征,同时,研究填料添加量及质量比(FG∶LDH)对环氧树脂胶黏剂黏接性能、疏水性能和热稳定性能的影响规律。结果表明,采用尿素法制备的LDH及FG-ZnAl-LDH为二维片层结构,LDH特征峰强度随FG比例增加而逐渐降低。填料添加量为2%,FG∶LDH=1∶1时,FG-ZnAl-LDH改性环氧树脂胶黏剂的性能最佳,其剪切强度较改性前提高26.32%,水接触角提高32.9%,热分解温度提高约5℃。研究表明氟化石墨烯/水滑石的添加,可在环氧树脂胶黏剂中起到增强效果,其不仅可以提高胶黏剂的黏接强度,而且对胶黏剂的疏水性和热稳定性也具有显著的提升作用。     

聚乙烯醇-二氧化硅/聚丙烯腈杂化复合膜渗透蒸发分离己内酰胺/水溶液

制备了以聚乙烯醇(PVA)填充纳米SiO2改性膜为活性层,聚丙烯腈(PAN)超滤膜为底膜的PVA-SiO2/PAN杂化复合膜,并用于己内酰胺(CPL)脱水。用FTIR,SEM,XRD,TGA分别对膜进行了表征,并考察了膜中纳米SiO2粒子的质量分数、进料组分质量分数和温度对复合膜分离性能的影响。结果表明,引入纳米SiO2后,杂化膜的热稳定性明显提高。当膜中纳米SiO2质量分数为1.0%时,复合膜渗透蒸发分离性能最佳。60℃下此复合膜用于分离质量分数为40%的CPL溶液时,其总通量和分离因子分别达到2 177 g/(m2.h)和349。     

Prestretching effect and recovery process of polyvinyl alcohol film crosslinked with tartaric acid

The tartaric acid (TA)/polyvinyl alcohol (PVA) composite films were prepared with various TA concentrations from 5 to 20 wt%. The crosslinking due to TA improved the tensile characteristics such as tensile strength and the Young's modulus, and thermal stability of the films. The addition of TA in PVA led to a decrease in the crystallinity. Application of prestretching or preliminary deformation resulted in significant changes in both stress–strain behavior and tensile characteristics of both pure PVA and TA/PVA composite films. Although low preextension levels such as 5% strain did not change much the tensile characteristics, higher preextension levels improved the tensile strength but decreased the extensibility of the films. The recovery processes of the stretched films consisted of a fast recovery process for which most of the recoverable elastic deformation is seen took place within almost 30 min and a time-dependent long-lasting recovery process continued in time very slowly, which resulted in undesirable residual deformation. It was also observed that increasing TA concentration accelerated the recovery process, hence, improved the recovery properties of PVA. The use of TA in the membrane applications can be considered to improve the mechanical properties and reusability of the membrane technology.     

层状Mg/Al氢氧化物/聚乙烯醇复合膜的制备及染料截留性能的研究

二维膜因其可控的结构和通道特有的物理化学性质,在气体分离、海水淡化、污水处理等诸多分离领域展现出巨大的应用潜力。通过层状Mg/Al氢氧化物（LDH）单片与聚乙烯醇（PVA）高分子链之间的氢键相互作用,层层堆叠构建了PVA/LDH复合膜。利用SEM、XRD考察了PVA与LDH的配比对于复合膜层状结构与层间距高度的影响规律。考察了PVA/LDH复合膜的纯水通量及染料模型分子的截留率。结果表明,不同PVA混合量的复合膜断面都具有层状结构。由于氢键作用导致复合膜较之于纯LDH膜的层间距有所缩小,随着PVA含量增加复合膜层间距先减小后增加;在PVA含量为15%时达到最小值,PVA含量超过15%后复合膜层间距有所增加。不同比例复合膜,以PVA质量分数为25%的复合膜的纯水通量最大;同时,该复合膜对分子量在300~800的染料分子具有优异的截留性能,截留率均超过97%。该工作为PVA/LDH复合膜在印染废水处理提供了新思路。     

凹凸棒土杂化粒子改性聚乙烯醇/壳聚糖复合膜的结构与性能研究

采用表面引发接枝聚合法制备凹凸棒土接枝聚丙烯酰胺杂化粒子(ATP-g-PAAm),以此改性聚乙烯醇/壳聚糖复合膜(PVA/CS).采用傅里叶红外光谱(FTIR)、差示扫描量热(DSC)、热失重分析(TG)等对三元复合膜(PVA/CS/ATP-g-PAAm)进行了表征,考察了杂化粒子含量对复合膜力学性能、热性能、吸湿率和...     

聚乙烯醇/氧化石墨烯分离膜的结构与性能

成膜材料聚乙烯醇（PVA）易溶胀,稳定性差,氧化石墨烯（GO）具有很好的化学稳定性,以PVA为主要原料,GO为添加剂,聚乙二醇为造孔剂,采用共混法制备了GO含量不同的PVA/GO分离膜,并用光学接触角测量仪、超滤杯等考察了分离膜的亲水性和耐污染性;采用SEM、IR、TGA等表征了分离膜的微观形貌、热学及力学性能。结果表明：GO的加入改善了分离膜的内部孔道、亲水性、纯水通量和耐污染能力,膜的热稳定性和力学性能均得到提高,当GO含量为2%时,分离膜的综合性能达到最优。     

Antibacterial Vancomycin@ZIF-8 Loaded PVA Nanofiber Membrane for Infected Bone Repair

Bone substitutes with strong antibacterial properties and bone regeneration effects have an inherent potential in the treatment of severe bone tissue infections, such as osteomyelitis. In this study, vancomycin (Van) was loaded into zeolitic imidazolate framework-8 (ZIF-8) to prepare composite particles, which is abbreviated as V@Z. As a pH-responsive particle, ZIF-8 can be cleaved in the weak acid environment caused by bacterial infection to realize the effective release of drugs. Then, V@Z was loaded into polyvinyl alcohol (PVA) fiber by electrospinning to prepare PVA/V@Z composite bone filler. The drug-loading rate of V@Z was about 6.735%. The membranes exhibited super hydrophilicity, water absorption and pH-controlled Van release behavior. The properties of anti E. coli and S. aureus were studied under the pH conditions of normal physiological tissues and infected tissues (pH 7.4 and pH 6.5, respectively). It was found that the material had good surface antibacterial adhesion and antibacterial property. The PVA/V@Z membrane had the more prominent bacteria-killing effect compared with the same amount of single antibacterial agent containing membrane such as ZIF-8 or Van loaded PVA, and the antibacterial rate was up to 99%. The electrospun membrane had good biocompatibility and can promote MC3T3-E1 cell spreading on it.     

纳米纤维素晶须-壳聚糖/聚乙烯醇复合膜性能与细胞相容性

以椰壳纤维为原料,制备了纳米纤维素晶须,用硅烷偶联剂对纳米纤维素晶须进行改性,将改性后纳米纤维素晶须与壳聚糖、聚乙烯醇共混,采用溶液浇铸法制备了改性纳米纤维素晶须-壳聚糖/聚乙烯醇复合膜。采用FTIR、DSC、TG、XRD和SEM对改性纳米纤维素晶须-壳聚糖/聚乙烯醇复合膜的结构、热性能、结晶行为和形貌进行表征与分析,对复合膜的力学性能和水接触角进行测试,将成纤维细胞L929接种到复合膜上,对其进行细胞相容性实验。结果表明,添加改性纤维素晶须,能够使壳聚糖/聚乙烯醇复合膜的热性能、结晶行为和力学性能提高,成纤维细胞在复合膜上具有较好的黏附和生长,制备的纳米纤维素晶须-壳聚糖/聚乙烯醇复合膜具有良好的综合性能和细胞相容性。     

Polyvinyl alcohol and acidity-regulating KH2PO4 synergistically accelerated degradation of PBAT/PLA composites

Poly(butylene adipate-co-terephthalate) (PBAT)/polylactic acid (PLA) composites were prepared by water-soluble polyvinyl alcohol (PVA) and degradation-promoting agent (DPA) which were made from acidity-regulating KH₂PO₄ and halloysite by a physical layer-by-layer coating method. The effect of PVA and DPA on the biodegradation of PBAT/PLA composites in the cross-sectional morphology, thermal properties, molecular structure, due to degradation was evaluated using a host of characterization methods. The results showed that PVA had a good solubilizing effect on the composite system and improved the overall compatibility. DPA had little effect on the compatibility, crystallinity, and thermal stability of the composite system, but greatly accelerated the degradation. The interior of composite material containing DPA (Com-DPA) was shown to be severely damaged after 29 weeks of degradation, which was attributed to preferential degradation of amorphous regions of the composite by ester hydrolysis. Our results demonstrated the PVA and DPA worked synergistically to promote swelling and diffusivity of degradation products, and provided an acid environment for enhancing ester hydrolysis. This technology may have good prospects for accelerated degradation of materials in agricultural applications.     

Development of biopolymer composite films based on chicory extract reinforced polyvinyl alcohol/chitosan blend via green approach for flexible optoelectrical devices

Biopolymer blend composite films based on polyvinyl alcohol (PVA) and chitosan (CS) incorporated with varying amounts of chicory extract (CE) have been developed by the green solution casting technique. The impact of CE content on structural, thermal, mechanical and electrical properties was thoroughly examined. The existence of intermolecular interactions in the blend composite was confirmed by Fourier-transform infrared and ultraviolet spectroscopy. The x-ray diffraction pattern proved the successful preparation of PVA/CS/CE composite film. The scanning electron microscopy images of the composites showed shape and grain size for the different bio-filler contents. The thermal transition temperature of the blend composites was significantly improved by the addition of CE extract deduced from differential scanning calorimetry. The dielectric study showed that the permittivity remarkably increases with decreasing frequency and maximum dielectric constant was observed for 15 wt% loading. The activation energy obtained from the AC conductivity decreased as the temperature increased. The addition of CE extract improved the hardness and tensile strength of the PVA/CS blend composite in comparison with a pristine pure blend. The controllable mechanical, thermal, optical, and electrical characteristics of the PVA/CS blend composite suggest that it might be an attractive optical material for the advancement of futuristic flexible-type optoelectronic and energy storage systems.     

Construction of lysozyme exfoliated rectorite‐based electrospun nanofibrous membranes for bacterial inhibition

Lysozyme (LY) exfoliated rectorite (REC) based electrospun nanofibrous membranes with enhanced bacterial inhibition ability and thermostability were fabricated via electrospinning. All the obtained membranes exhibited better fiber shape and three‐dimensional structure, which could be observed by scanning electron microscopy. Energy‐dispersive X‐ray analysis, X‐ray photoelectron spectroscopy, and Fourier transform infrared (FTIR) spectrum denoted the existence of LY and REC in the composite membranes. Besides, the FTIR results suggested that there were interactions between REC and polyvinyl alcohol (PVA)/LY chains. Small angle X‐ray diffraction indicated that REC was exfoliated by PVA and LY chains. In addition, the exfoliation of REC was directly confirmed by transmission electron microscopy. According to Brunauer‐Emmett‐Teller surface area test results, PVA/LY/REC membranes had higher surface area than that of PVA/LY membranes. The performance tests showed that both the thermal stability and antibacterial activity of the composite membranes were enhanced after adding REC. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41496.