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1.
以聚乙烯醇(PVA)和正硅酸乙酯(TEOS)为原料,通过溶胶-凝胶(Sol-Gel)技术,制备出不同nano-SiO2含量的PVA/nano-SiO2杂化膜,并采用扫描电子显微镜(SEM)、X射线衍射仪(XRD)等仪器测试和分析了杂化膜的结构和性能。结果表明:随着nano-SiO2含量的增加,PVA杂化膜的耐水性能增强,结晶能力下降,而力学性能呈现先增大后减小的趋势。当nano-SiO2的加入量在10%左右时,断裂伸长率由纯PVA膜的34.74%提高到55.52%,拉伸强度从33.08 MPa增加到49.98 MPa;而当nano-SiO2含量增加到20%以上时,nanoSiO2粒子会发生团聚,使得杂化膜的力学性能变差。 相似文献
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以聚乙烯醇(PVA)与聚乙二醇(PEG)共混,并与正硅酸乙酯(TEOS)进行交联反应制备杂化膜。FTIR证实杂化溶胶液发生交联反应形成共价键Si—O—C,WXRD观察表明加入TEOS改变了膜结晶度,加入PEG提高了PVA膜对乙醇/水溶液的渗透通量,但分离因子下降,随着TEOS的加入,膜的分离因子提高。在TEOS质量分数为10%时,杂化膜的分离因子达到最大。提高退火温度可以提高膜的分离因子,但通量下降。在100℃下退火12 h的杂化膜对乙醇质量分数为85%的乙醇/水溶液的分离性能最佳。 相似文献
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采用壳聚糖(CS)和1,3丙磺酸内酯反应生成—SO3H基团并依次加入聚乙烯醇(PVA)和正硅酸四乙酯(TEOS),通过溶胶凝胶法与磺化CS交联制备一系列具有不同磺化CS含量的新型磺化PVA/CS/SiO2杂化膜。采用傅里叶变换红外光谱、扫描电子显微镜和动态热力学测试技术、以及离子交换容量,含水量、线性膨胀率等数据系统地研究了磺化CS含量对杂化膜的物理和化学性能的影响。结果表明,膜的水含量、线性膨胀率和离子交换容量的范围分别为10 %~25 %、15 %~20 %、0.10~0.65 mmol/g;制备的杂化膜拥有优异的OH-离子渗析性能和可接受的选择性,渗析系数(UOH)和分离因子(S)范围分别为0.0135~0.0160 m/h、15.6~26.9。 相似文献
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聚酰亚胺/二氧化硅杂化膜的制备与介电性能的研究 总被引:1,自引:0,他引:1
采用溶胶-凝胶法制备了BTDA-ODA聚酰亚胺/SiO2杂化膜,利用红外分光光度计(FTIR)、热重分析仪(TGA)和透射电镜(TEM)研究了杂化膜的微观结构和热性能,并对杂化膜的介电常数(e)和介电损耗(tand)随SiO2粒子含量和电场频率的变化进行了分析和讨论。结果表明:杂化膜的介电常数和介电损耗随SiO2粒子含量的增加而增大,随电场频率的升高而逐渐降低,用考虑到粒子的形状因素和两相间相互作用的EMT模型可以预测聚酰亚胺/SiO2杂化膜的介电常数。 相似文献
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以正硅酸乙酯(TEOS)为前驱体,戊二醛(GA)为交联剂,利用溶胶凝胶法和原位化学交联法相结合的方法,制备了交联的聚乙烯醇/二氧化硅(PVA/SiO2)杂化功能膜。通过FTIR、SEM、溶胀和拉伸实验研究了二氧化硅和原位化学交联对杂化膜结构和性能的影响。结果表明,制备的膜是具有梯度交联结构的有机/无机杂化体系,原位化学交联对膜断面形貌影响不大。二氧化硅的引入和戊二醛原位交联都能有效地降低杂化膜的平衡溶胀度,两种因素在提高杂化膜耐水性方面具有互补作用。 相似文献
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通过熔融接枝反应将乙烯基三甲氧基硅烷(VTMS)接枝到聚乙烯蜡(PEW)分子链上,接枝物红外光谱(FTIR)的1090、1030、960 cm-1等处出现了—Si—O—CH3的特征吸收峰。以正硅酸乙酯(TEOS)为前驱体,混入接枝PEW中,通过溶胶-凝胶法(sol-gel)制备了PEW/SiO2杂化材料。使用透射电镜(TEM)和热重分析(TG)研究了杂化材料的形态及性能,结果表明,通过sol-gel可以制备SiO2含量为0. 98%~4. 12%的杂化材料,SiO2颗粒与PEW接枝物分子间具有良好的相容性,纳米SiO2的存在提高了PEW的耐热性能,当SiO2含量为3. 75%时,PEW的分解温度提高了21. 34℃。 相似文献
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溶胶-凝胶法制备环氧树脂/SiO2杂化材料的研究 总被引:4,自引:0,他引:4
以环氧树脂、正硅酸乙酯(TEOS)、У-氨丙基三乙氧基硅烷(KH-550)为原料,采用溶胶-凝胶(Sol-Gel)法制备了环氧树脂/SiO2杂化材料。研究了TEOS用量、KH-550用量、温度对环氧树脂/SiO2杂化材料性能的影响。利用透射电镜(TEM)研究了SiO2在杂化材料中的分散状态,利用扫描电镜(SEM)对杂化材料的拉伸断口的微观形貌进行了研究,并用差示扫描量热(DSC)法研究了杂化材料的耐热性能。结果表明,TEOS含量在3%,KH-550含量在2%、反应温度在60℃时,杂化材料的拉伸强度、断裂伸长率、冲击强度和弯曲强度分别提高了30.1%、53.9%、34.4%、12.5%;生成的SiO2颗粒的平均尺寸为20nm左右;杂化材料玻璃化温度比纯环氧树脂提高20℃以上。 相似文献
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PVA-TEOS/PAN渗透汽化膜的制备及其乙酸乙酯脱水 总被引:2,自引:0,他引:2
以聚丙烯腈(PAN)中空纤维超滤膜为底膜,以聚乙烯醇(PVA)和正硅酸乙酯(TEOS)的混合液为涂膜液,采用溶胶-凝胶法制备了PVA-TEOS/PAN渗透汽化复合膜,并用于乙酸乙酯脱水. FT-IR和XRD谱图证实复合膜表层中由于PVA与TEOS的交联反应而形成了Si?O?C共价键,且PVA的结晶度下降. 另外,利用静态接触角测量对复合膜表层的亲水性进行了表征. 考察了复合膜在乙酸乙酯水溶液中的溶胀性能及涂膜液中TEOS含量和料液温度与浓度对PVA-TEOS/PAN复合膜分离性能的影响. 结果表明,TEOS的加入有效降低了复合膜在乙酸乙酯水溶液中的溶胀度,使其对水具有较好的分离选择性. 40℃下,涂膜液中TEOS质量含量分别为5%和30%的PVA-TEOS/PAN复合膜分离98%的乙酸乙酯水溶液时,其分离因子分别为2830和4448,渗透通量分别为49.4和41.4 g/(m2×h). 相似文献
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聚乙烯醇/二氧化硅互穿网络膜的研究 总被引:1,自引:0,他引:1
采用溶胶凝胶法制备了聚乙烯醇/二氧化硅有机/无机互穿网络结构。扫描电子显微镜(SEM)观察到样品表面光滑,均匀;原子力显微镜(AFM)观察到样品中无机相与有机相呈互穿网络结构,且随无机物的增多两相分布更均匀;元素分析结果为纯PVA中w(O)为38%,随着无机物的增多w(O)逐渐降低为24.9%,是硅羟基与醇羟基之间脱去水,两相之间进行交联的结果;29SiNMR表明随无机物的增多,化学位移Q3的强度有所降低而化学位移Q4值却略有上升,说明硅羟基含量逐渐减少,两相交联程度逐渐增大,与元素分析结果相印证;热重曲线(TG)表明,无机物的加入使PVA的热降解温度由400℃提高到420℃,进一步证明两相之间已形成网状结构。 相似文献
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Poly(vinyl alcohol) (PVA) blended with poly(ethylene glycol) (PEG) was crosslinked with tetraethoxysilane (TEOS) to prepare organic–inorganic PVA/PEG/TEOS hybrid membranes. The membranes were then used for the dehydration of ethanol by pervaporation (PV). The physicochemical structure of the hybrid membranes was studied with Fourier transform infrared spectra (FT‐IR), wide‐angle X‐ray diffraction WXRD, and scanning electron microscopy (SEM). PVA and PEG were crosslinked with TEOS, and the crosslinking density increased with increases in the TEOS content, annealing temperature, and time. The water permselectivity of the hybrid membranes increased with increasing annealing temperature or time; however, the permeation fluxes decreased at the same time. SEM pictures showed that phase separation took place in the hybrid membranes when the TEOS content was greater than 15 wt %. The water permselectivity increased with the addition of TEOS and reached the maximum at 10 wt % TEOS. The water permselectivity decreased, whereas the permeation flux increased, with an increase in the feed water content or feed temperature. The hybrid membrane that was annealed at 130°C for 12 h exhibited high permselectivity with a separation factor of 300 and a permeation flux of 0.046 kg m?2 h?1 in PV of 15 wt % water in ethanol. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 相似文献
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气相、沉淀、稻壳SiO2/聚乙烯醇复合膜的性能比较 总被引:1,自引:0,他引:1
分别采用气相SiO2、沉淀SiO2和稻壳SiO2与聚乙烯醇(PVA)接不同的比例制备成复合膜。比较了3种不同来源的纳米SiO2/PVA复合膜的拉伸性能及耐水性能。结果表明:SiO2含量相同时,复合膜的断裂伸长率和拉伸强度的排列顺序为:气相SiO2/PVA〉稻壳SiO2/PVA〉沉淀SiO2/PVA;拉伸模量的排列顺序为:气相SiO2/PVA〉沉淀SiO2/PVA〉稻壳SiO2/PVA;3种来源的SiO2都可以提高PVA的耐水性,且耐水性随SiO2含量的增大而增强,SiO2含量相同时,复合膜的耐水性排列顺序为:气相SiO2/PVA〉沉淀SiO2/PVA〉稻壳SiO2/PVA。 相似文献
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采用溶胶-凝胶法制备了聚乙烯醇(PVA)/γ-氨丙基三乙氧基硅氧烷(APTEOS)有机/无机杂化膜。用FTIR和XRD对杂化膜进行了表征。测定了膜在乙醇/水溶液中的溶胀行为。考察了杂化膜对85%(质量)的乙醇/水溶液的渗透蒸发分离性能。加入APTEOS降低了PVA的结晶度,有效控制了膜的溶胀,呈现出优良的分离性能。随着APTEOS含量的增加,杂化膜的选择性急剧增加,在5.0%(质量)时达到最大值;同时膜的渗透通量迅速增加。解决了PVA膜trade-off效应。 相似文献
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以正硅酸乙酯(TEOS)和聚乙烯醇(PVA)为原料,采用溶胶-凝胶法制备PVA/SiO2杂化材料,研究丁其制尊T艺和作为玻璃板防雾涂层的应用;通过FT—IR分析证明SO-O-Si的生成及-OH键的保留,使用分光光度计研究其透光率,并对不同质量分数(SiO2)下的雾度、硬度和耐水性进行了讨论。 相似文献
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Novel hybrid organic–inorganic membranes were prepared via sol–gel reactions of quaternized poly(vinyl alcohol) (q‐PVA) and γ‐aminopropyltriethoxysilane (APTEOS) for pervaporation dehydration of an 85 wt % ethanol solution. The physicochemical structure of the hybrid membranes was characterized by FTIR, XRD, SEM, TG, and TEM. Nanofractal objects originated from self‐assembly of ammonium groups on the q‐PVA chains and amino groups in APTEOS can be observed on the surface of the hybrid membranes. When APTEOS/PVA ratio is 5% (wt/wt), the hybrid membrane has specific nervate networks on its surface and exhibits the highest separation factor. The hybrid membranes have better pervaporation performance than pristine q‐PVA membrane, and their permeation flux was found to increase linearly with increasing APTEOS content. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
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Physical and gas transport properties of hyperbranched polyimide-silica hybrid membranes were investigated. Hyperbranched polyamic acid as a precursor was prepared by polycondensation of a triamine, 1,3,5-tris(4-aminophenoxy) benzene (TAPOB), and a dianhydride, 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), and subsequently modified a part of end groups by 3-aminopropyltrimethoxysilane (APTrMOS). The hyperbranched polyimide-silica hybrid membranes were prepared by sol–gel reaction using the polyamic acid, water, and alkoxysilanes. 5% weight-loss temperature of the hybrid membranes increased with increasing silica content, indicating effective crosslinking at polymer-silica interface mediated by APTrMOS moiety. On the other hand, glass transition temperature of the hybrid membranes prepared with methyltrimethoxysilane (MTMS) showed a minimum value at low silica content region, suggesting insufficient formation of three-dimensional Si O Si network compared to the hybrid membranes prepared with tetramethoxysilane (TMOS). CO2, O2, N2, and CH4 permeability coefficients of the hybrid membranes increased with increasing silica content. Especially for TMOS/MTMS combined system, the hybrid membranes showed simultaneous enhancements of gas permeability and CO2/CH4 separation ability. It was concluded that the 6FDA-TAPOB hyperbranched polyimide-silica hybrid membranes have high thermal stability and excellent CO2/CH4 selectivity and are expected to apply to high-performance gas separation membranes. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
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将超支化聚酯(HBPE)与聚乙烯醇(PVA)共混交联制备了PVA/HBPE交联渗透汽化膜,研究了PVA/HBPE交联膜内的溶解扩散及渗透汽化性能。结果表明,随着温度的增加,水在交联膜内的渗透系数(Pwater)增加,且变化趋势与纯水通量一致,在55 ℃时达到最大值71.952 g/m2·h;随着HBPE含量的增加,渗透系数Pwater及纯水通量呈现增加的趋势,当HBPE含量为40 %时,纯水通量达到最大值185.726 g/m2·h。 相似文献
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A novel copper‐poly(vinyl alcohol) (PVA)/silica complex was prepared and its chemical structure, thermal, and mechanical properties were studied. The results showed that the crystallinity of PVA first increased and then decreased by the addition of copper chloride, whereas, the thermal decomposition temperature increased dramatically. For PVA/silica hybrid, the decomposition temperature associated with the removal of water molecules in PVA chains was 262°C. But the temperature increased to 361°C when the content of copper chloride was 2 wt%. The intelligent electronic tensile tester was used to investigate the mechanical properties of these complexes. The results suggested that the tensile strength of the complexes is improved with negligible decrease in the plasticity. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers 相似文献