加工芳纶纳米纤维/聚乙烯醇水凝胶制备高强度复合薄膜

芳纶纳米纤维(ANF)具有大长径比、高比表面积、丰富的表面酰胺官能团和优异的力学性能,是制备高强度纳米复合材料的理想构筑单元。本文开发了一种新颖的水凝胶加工策略,用于制备ANF增强聚乙烯醇(PVA)复合薄膜,逐步优化了ANF的含量、水凝胶的预拉伸比和PVA组份的化学交联,表征分析了复合薄膜中ANF的分散、取向、PVA的交联形式及ANF与PVA之间的界面氢键作用,当ANF的质量分数为25wt%、水凝胶的预拉伸比为55%和采用氯化铜交联PVA基体时,复合薄膜的力学性能最优,其杨氏模量和拉伸强度分别高达(14.6±0.3) GPa 和(496.5±10.0) MPa,远远优于文献报道的ANF增强聚合物复合材料。此外,该高强度纳米复合薄膜同时具有良好的透明性和优异的紫外屏蔽性能,透明度大于72.1%,能够屏蔽大于99.98%紫外线,可用做先进包装材料。      

磺胺嘧啶银/聚乙烯醇水凝胶复合材料的制备及性能表征

采用e-Beam电子辐射和冻融循环相结合的方法制备了磺胺嘧啶银(SD-Ag)/聚乙烯醇(PVA)水凝胶。研究了制备工艺对PVA水凝胶的性能的影响。通过拉伸性能测试、吸水率检测、SEM和FT-IR等表征,考察了PVA浓度(占总质量5%~15%)、冻融与辐射处理等对PVA水凝胶拉伸强度、断裂伸长率、吸水性、凝胶含量和微观结构等的影响。结果表明:随着PVA浓度增大,PVA水凝胶的拉伸强度提高。当PVA浓度为15%、辐射剂量为25kGy时,单独辐射、辐射后冻融及冻融后辐射三种工艺制备的PVA水凝胶拉伸强度分别为0.023 MPa、0.048MPa、0.028MPa,吸水率分别为为95%、45%、63%,说明经冻融处理的水凝胶力学强度提高,吸水率有所下降。然后,选择适当的制备工艺并在PVA水凝胶中加入SD-Ag,考察了SD-Ag/PVA水凝胶的抑菌性能,抑菌活性测试结果显示,随着SD-Ag含量的增加,SD-Ag/PVA水凝胶的抑菌效果增强,而且其对革兰式阴性菌(大肠杆菌)的抑菌效果优于其对革兰式阳性菌(金黄色葡萄球菌)的抑菌效果。     

高透明度聚乙烯醇水凝胶的制备、表征及透明机理研究

用二甲基亚砜(DMSO)水溶液通过冷冻/解冻法制备了高透明度聚乙烯醇(PVA)水凝胶,使用差示扫描量热仪(DSC)、紫外吸收光谱、力学性能分析仪、紫外-可见分光光度计等分析了DMSO浓度对聚乙烯醇水凝胶透光率的影响,并表征了PVA水凝胶的含水率、结晶度、力学性能等性质.结果表明,用含量为80%(质量分数)的DMSO水溶液制备的PVA水凝胶得到了高达(99.8±0.2)%透明度,其抗拉强度达到3MPa以上,断裂拉伸率＞600%.研究发现,DMSO与水形成的1DMSO/2H2O网络结构能够限制PVA分子在三维方向的结晶,同时能够促进二维方向PVA晶体的生长.当DMSO含量为80%时,溶液中DMSO与水的比例略＞1:2,存在少量未形成1:2网络结构的DMSO分子,该分子与PVA羟基形成氢键限制了PVA分子在二维方向的结晶,最终导致PVA水凝胶中PVA晶体的体积最小、PVA晶体的数目最多,从而得到了最高的水凝胶透明度和较好的力学性能.     

PVA纳米涂布PE抗菌薄膜制备及其包装性能研究

采用KH570改性纳米Zn O、NDZ-101改性纳米Ti O2,利用FT-IR和TEM表征改性粉体表面结构和性质变化。配制PVA纳米溶胶,采用涂布法制备PVA纳米Zn O/PE和PVA纳米Ti O2/PE复合薄膜。利用电子万能试验机、透氧测试仪、透湿测试仪和贴膜法研究分析复合薄膜的力学、阻隔和抗菌性能。结果表明,PVA纳米Zn O/PE和PVA纳米Ti O2/PE在纳米粉体添加量为1%左右时可获得良好的力学性能和阻隔性能;PVA纳米Zn O/PE薄膜在避光、自然光和紫外光下抗菌率均达90%以上,PVA纳米Ti O2/PE薄膜在自然光和紫外光下抗菌率达97%以上。     

聚乙烯醇改性对原子层沉积氧化铝复合隔膜的影响

原子层沉积技术(ALD)是一种具有表面自限性反应的薄膜生长技术,可以精准控制薄膜的生长。本文研究了ALD技术包覆聚烯烃隔膜,制作纳米氧化铝聚烯烃复合隔膜。聚烯烃膜表面无ALD氧化铝反应基团,造成ALD氧化铝生长成核慢,前期反应效率低,最终生长的氧化铝多形成团簇而非完整覆盖的薄膜。为了增强ALD氧化铝包覆聚乙烯膜(PE)的全覆盖薄膜生长,将PE膜进行了聚乙烯醇(PVA)表面改性处理,然后进行ALD Al_2O_3生长。通过扫描电镜、红外光谱、电感耦合发射光谱仪等技术手段系统分析了PVA表面改性对ALD Al_2O_3包覆PE膜性能指标的影响。结果表明,PVA改性可以简单有效地在PE膜上增加羟基(-OH)作为ALD反应位点。处理后的PE膜进行ALD Al_2O_3生长,前驱体进入反应腔室后更易与表面羟基进行反应,提高表面生长效率,纤维上均匀包覆氧化铝,无岛状生长的Al_2O_3团簇。同时PVA改性可以增强复合膜的耐热收缩性能,减少厚度增加,减轻机械结构的损坏。     

锡青铜表面超疏水薄膜的制备及其水润滑减摩性能

为了改善锡青铜在水润滑条件下的摩擦性能,在其表面以1％氟硅烷乙醇溶液制备了超疏水薄膜.通过扫描电镜(SEM)观察了超疏水薄膜的表面形貌,测量了其接触角;在CETRUMT-2球-盘摩擦磨损试验机上考察了超疏水薄膜水润滑下的减摩性能.结果表明:锡青铜表面刻蚀并成膜后形成了粗糙的微纳复合结构,刻蚀40 min表面接触角可达151.1°,具备超疏水性能;超疏水薄膜在水润滑下具有较低的摩擦系数,可有效降低摩擦副的磨损.     

微波原位合成2D Ni-Fe MOF/硅藻土复合材料及其改性聚乙烯醇水凝胶不锈钢筛网油水分离性能

如何高效处理含油污水的问题,是如今世界科研人员共同关注的问题。聚乙烯醇(PVA)水凝胶作为高含水量及具有三维亲水网络的软材料在油水分离领域引起了广泛的关注。但是,和大多数具有超润湿性质的水凝胶一样,PVA水凝胶类油水分离材料不仅力学性能差,同时也存在化学稳定性差的问题。基于此,通过微波法制备了2D Ni-Fe金属-有机框架材料(MOF)-硅藻土(Dia)纳米材料及其PVA复合水凝胶。同时,不锈钢网经过浸泡2D Ni-Fe MOF-Dia/PVA水凝胶溶液得到2D Ni-Fe MOF-Dia/PVA水凝胶不锈钢筛网,表现出超亲水-水下超疏油性质。利用SEM、XPS分析2D Ni-Fe MOF-Dia及其复合水凝胶的化学组成和表面形貌。研究了2D Ni-Fe MOF-Dia/PVA复合水凝胶的力学性能及2D Ni-Fe MOF-Dia/PVA复合水凝胶不锈钢筛网的油水分离与乳液分离的分离效率及水通量,并对其耐盐性、耐酸耐碱性油水分离性能进行了测试。结果表明:2D Ni-Fe MOF-Dia/PVA复合水凝胶具有优异的力学性能,拉伸与压缩强度分别达到1.49 MPa及0.58 MPa,同时表现出超亲水-水下超疏油性质,2D Ni-Fe MOF-Dia/PVA不锈钢筛网的油水分离与乳液分离效率与通量分别可达99.2%和742.7 L·m?2·h?1。在酸性、碱性、盐性环境下均保持优异的分离效率与通量,并且在5次循环后,依旧保持稳定的分离效率与通量。      

PVA/明胶/Fe_3O_4磁敏感性水凝胶的制备及性能研究

采用物理交联的方法制备了聚乙烯醇(PVA)/明胶/Fe3O4磁敏感性水凝胶。对Fe3O4磁敏感性水凝胶在加入明胶前后的力学性能及溶胀性能进行了对比分析,利用SEM、IR等对水凝胶进行表征,采用振动样品磁强计测试了其磁敏感性。结果表明,PVA/Fe3O4磁敏感性水凝胶加入明胶后,其力学性能明显增强,提高了0.4~0.7MPa,当磁性粒子含量为1.5%时,力学性能较好;加入明胶后,水凝胶脱水率和溶胀度都随着磁性粒子增加而增大;从SEM照片及IR图上可知,加入明胶后,PVA、明胶和Fe3O4三者相容性较好;测得的水凝胶磁敏感性较好。     

疏水性透明γ-AlOOH/FAS复合薄膜的制备与性能

采用溶胶-凝胶法和表面改性结合的方法制备了疏水性透明-γAlOOH/FAS复合薄膜,勃姆石(γ-AlOOH)薄膜经沸水处理表面形成网格状粗糙结构,氟硅烷(十三氟辛基三乙氧基硅烷,FAS)被用作疏水剂涂敷在勃姆石薄膜表面。研究采用XRD,SEM,接触角测定仪及UV-vis分光光度计对薄膜相结构、表面形貌、接触角及可见光透过率进行了一系列表征。研究结果表明:采用溶胶-凝胶法和表面改性结合的方法制备的-γAlOOH/FAS复合薄膜具有高的透明性和疏水性,复合薄膜对可见光透过率达90%以上,对水的接触角为120.3°。     

三乙醇胺硼酸酯交联制备聚乙烯醇水凝胶及其吸附性能研究

采用三乙醇胺硼酸酯与聚乙烯醇(PVA)交联反应制备了水凝胶,通过红外光谱和扫描电镜来观察PVA水凝胶结构和形貌进行了表征,并PVA对水凝胶的溶胀性和吸附性进行分析研究。研究结果表明PVA水凝胶内存在较强的氢键作用,部分三乙醇胺接枝在PVA分子链上。三乙醇胺硼酸酯交联10%(质量分数)PVA水溶液时,所得凝胶的溶胀度接近700%。PVA水凝胶内部大孔套小孔相互交织,构成了复杂的不规则孔洞和通道。PVA水凝胶对Cu²⁺的色素去除率最高达91%,最大吸附量为10.2 mg/g,其吸附过程符合Langmuir方程模型,属单分子层吸附。     

Small-angle X-ray scattering and FTIR characterization of nanostructured poly (vinyl alcohol)/silicate hybrids for immunoassay applications

In the present work we aimed to develop and characterize hybrid organic–inorganic materials based on poly(vinyl alcohol) (PVA) polymer chemically modified by organosilanes and crosslinked network to be tested as solid support on immunoassay application. Hybrids were synthesized by reacting PVA with 5 different alkoxysilanes modifying chemical groups: tetraethoxysilane (TEOS), 3-mercaptopropyltriethoxysilane (MPTES), 3-glycidoxypropyltrimethoxysilane (GPTMS), 3-(triethoxysilyl)propylisocyanate (TESPI), and 3-aminopropyltriethoxysilane (APTES). PVA-derived hybrids were also modified by chemically crosslinking with glutaraldehyde (GA) during the synthesis reaction. In order to investigate the structure in the nanometer-scale, PVA-derived hybrids were characterized by using small-angle X-ray scattering synchrotron radiation (SAXS). Fourier transform infrared spectroscopy (FTIR) was used to investigate PVA hybrids chemical functionalities and their interaction with bovine herpesviruses. The morphology of silane modified PVA films were also analyzed by SEM coupled to EDX. The bioactivity assays were tested through Enzyme Linked Immunosorbent Assay (ELISA) with bovine herpesvirus (BoHV). SAXS results have indicated nano-ordered disperse domains for PVA hybrids with different X-ray scattering patterns for PVA polymer and PVA-derived hybrids. FTIR spectra have clearly showed that the proposed modifications of PVA by organosilanes were obtained. The chemical crosslinking of PVA polymer chain by GA was verified by FTIR. The immunoassay results have showed that PVA hybrids with chemically functionalized structures have played an important role on regulating to some extent the interaction of herpesvirus and solid substrate at the interface. These results have given strong evidence that PVA-derived hybrid nanocomposites were successfully formed with GA crosslinked network. Also, such PVA based material could be advantageously used in immunoassays with enhanced specificity for diagnosis.     

Chemical synthesis of highly stable PVA/PANI films for supercapacitor application

Polyvinyl alcohol (PVA)/polyaniline (PANI) thin films were chemically synthesized by adopting two step process: initially a thin layer (200 nm) of PVA was spin coated by using an aqueous PVA solution onto fluorine doped tin oxide (FTO) coated glass substrate, afterwards PANI was chemically polymerized from aniline monomer and dip coated onto the precoated substrate. The thickness of PANI layer was varied from 293 nm to 2367 nm by varying deposition cycles onto the precoated PVA thin film. The resultant PVA/PANI films were characterized for their optical, morphological and electrochemical properties. The FT-IR and Raman spectra revealed characteristic features of the PANI phase. The SEM study showed porous spongy structure. Electrochemical properties were studied by electrochemical impedance measurement and cyclic voltammetry. The electrochemical performance of PVA/PANI thin films was investigated in 1 M H₂SO₄ aqueous electrolyte. The highest specific capacitance of 571 Fg⁻¹ was observed for the optimized thickness of 880 nm. The film was found to be stable for more than 20,000 cycles. The samples degraded slightly (25% decrement in specific capacitance) for the first 10,000 cycles. The degradation becomes much slower (10.8% decrement in specific capacitance) beyond 10,000 cycles. This dramatic improvement in the electrochemical stability of the PANI samples, without sacrificing specific capacitance was attributed to the optimized PVA layer.     

Chemical,morphological, and mechanical analysis of rice husk/post-consumer polyethylene composites

Composites were obtained from post-consumer high-density polyethylene (PE) reinforced with different concentrations of rice husk. PE and rice husk were chemically modified to improve their compatibility in composite preparation. Rice husk was mercerized with a NaOH solution and acetylated. The chemically modified fibers were characterized by FTIR and ¹³C NMR spectroscopy. The composites were prepared by extrusion of modified and unmodified materials containing either 5 or 10 wt.% fibers. The morphology of the obtained materials was analyzed by SEM. The chemical modification of the fiber surface was found to improve its adhesion with matrix. Flexural and impact tests demonstrated that PE/rice husk composites present improved mechanical performance comparatively to the pure polymer matrix, on the contrary no benefit is observed in the tensile strength over the pure PE.     

FTIR spectroscopy characterization of poly (vinyl alcohol) hydrogel with different hydrolysis degree and chemically crosslinked with glutaraldehyde

In this work, poly (vinyl alcohol) (PVA) hydrogels with different degree of hydrolysis (DH) were prepared by chemical crosslinking with glutaraldehyde (GA). The nanostructure of the resulting hydrogels was investigated by Fourier Transform Infrared Spectroscopy (FTIR) and Synchrotron small-angle X-ray scattering characterization (SAXS). In vitro tests were performed by swelling ratio assays in different pH solutions. The infrared spectra of the crosslinked PVA showed absorption bands of the acetal bridges resulted from the reaction of the GA with the OH groups from PVA. Also the FTIR spectroscopy was used to determine the crystallinity of the PVA film based on the relative intensity of the vibration band at 1141 cm^− 1. The results have showed an increase of hydrogel crystallinity with higher DH of PVA. SAXS patterns have clearly indicated important modifications on the PVA semicrystalline structure when it was crosslinked by GA. The swelling ratio was significantly reduced by chemically crosslinking the PVA network. PVA-derived hydrogel with chemically modified network was found to be pH-sensitive, indicating a high potential to be used in drug delivery polymer system.     

PVA/PAN渗透汽化膜分离乙酸乙酯—乙醇—水体系的研究

采用相转化法制备了平板PAN超滤膜,并采用涂覆法制备了酒石酸交联的PVA/PAN复合膜.利用红外谱图和扫描电镜对复合膜表面化学组成及膜结构进行了分析和表征.同时,以乙酸乙酯-乙醇-水体系为研究对象,分别研究了交联荆的含量以及料液温度等对复合膜性能的影响.结果表明在同一温度下,交联剂含量增加,膜的溶胀度减小,渗透通量减小.选择性增高.随温度的升高,渗透通量增大,而选择性降低.在30～50℃的料液温度下,复合膜的总通量为30～150 g/(m2·h),分离因子可达480～29 000.     

戊二醛交联对CCMC/PVA复合膜性能的影响

采用流延成膜工艺制备了CCMC/PVA共混复合膜,研究了戊二醛交联剂对复合膜的透光性能和力学性能的影响。结果表明:交联处理膜的致密性和机械性能显著提高;当戊二醛添加量为2%(质量分数),体系的pH为10,交联反应温度为85℃,交联时间为35 min时,复合膜的拉伸强度可达18.91 MPa,断裂伸长率为226%,透光率为75%。     

PVA/淀粉单层和多层复合材料的制备和性能研究

利用流延成形的方法制备PVA/淀粉单层和多层复合薄膜,并通过硅溶胶对其进行改性,对其力学性能和亲水性能进行研究,通过扫描电镜（SEM）、傅里叶红外（FT-IR）等对其进行表征。FT-IR结果表明,SiO₂与淀粉或PVA间发生脱水缩合,分子链间产生交联,SiO₂含量越多,交联程度越大。通过薄膜拉伸断口的SEM分析,在多层结构中,SiO₂颗粒能起到更好的增强增韧效果,多层结构比单层结构有着更高的抗拉强度和断裂延伸率。     

聚乙烯醇/橘皮果胶/阿魏酸复合包装膜的制备及性能研究

目的 为开发一种具有抗氧化活性和紫外屏蔽性的聚乙烯醇复合包装薄膜,从橘皮中提取果胶,探索聚乙烯醇/橘皮果胶/阿魏酸复合膜的性能。方法 首先用柠檬酸提取橘皮中的果胶,然后以阿魏酸为交联剂,用溶液共混浇筑法制备聚乙烯醇/橘皮果胶/阿魏酸复合薄膜。通过对复合薄膜结构、形貌、热性能、耐水性能、光学性能、力学性能、抗氧化性能的表征,考察不同含量的阿魏酸对复合薄膜的影响。结果 果胶羧基与聚乙烯醇羟基形成酯键,阿魏酸与聚合物形成酯键与氢键,薄膜具有较好的热稳定性和紫外屏蔽能力,加入阿魏酸后薄膜的耐水性能显著提升,拉伸强度和抗氧化活性显著增加。其中,当阿魏酸质量分数为5%时薄膜水溶性降低了38.89%,耐水性能最佳。结论 阿魏酸的加入提高了聚乙烯醇复合薄膜的耐水性能,薄膜具有良好的紫外屏蔽能力和抗氧化活性,是一种十分具有潜力的可持续包装材料。     

二步钝化法处理黄铜制品的研究

介绍了不同处理方式对黄铜制品经二步钝化法处理后形成钝化膜外观，色泽及结构的影响，并通过扫描电镜对钝化膜结构进行了表征，试验结果表明，黄铜制品在酸蚀后经1号钝化液钝化15s，2号钝化液钝化30s所形成的钝化膜结构致密、性能优良。