Modification of Thin Film Composite PVA/PAN Membranes for Pervaporation Using Aluminosilicate Nanoparticles

The effect of the modification of the polyvinyl alcohol (PVA) selective layer of thin film composite (TFC) membranes by aluminosilicate (Al₂O₃·SiO₂) nanoparticles on the structure and pervaporation performance was studied. For the first time, PVA-Al₂O₃·SiO₂/polyacrylonitrile (PAN) thin film nanocomposite (TFN) membranes for pervaporation separation of ethanol/water mixture were developed via the formation of the selective layer in dynamic mode. Selective layers of PVA/PAN and PVA-Al₂O₃·SiO₂/PAN membranes were formed via filtration of PVA aqueous solutions or PVA-Al₂O₃·SiO₂ aqueous dispersions through the ultrafiltration PAN membrane for 10 min at 0.3 MPa in dead-end mode. Average particle size and zeta potential of aluminosilicate nanoparticles in PVA aqueous solution were analyzed using the dynamic light scattering technique. Structure and surface properties of membranes were studied using scanning electron microscopy (SEM), atomic force microscopy (AFM) and water contact angle measurements. Membrane performance was investigated in pervaporation dehydration of ethanol/water mixtures in the broad concentration range. It was found that flux of TFN membranes decreased with addition of Al₂O₃·SiO₂ nanoparticles into the selective layer due to the increase in selective layer thickness. However, ethanol/water separation factor of TFN membranes was found to be significantly higher compared to the reference TFC membrane in the whole range of studied ethanol/water feed mixtures with different concentrations, which is attributed to the increase in membrane hydrophilicity. It was found that developed PVA-Al₂O₃·SiO₂/PAN TFN membranes were more stable in the dehydration of ethanol in the whole range of investigated concentrations as well as at different temperatures of the feed mixtures (25 °C, 35 °C, 50 °C) compared to the reference membrane which is due to the additional cross-linking of the selective layer by formation hydrogen and donor-acceptor bonds between aluminosilicate nanoparticles and PVA macromolecules.     

PBS-co-DEG与热塑性淀粉共混膜的性能研究

采用流延法制备了不同二甘醇(DEG)含量的聚丁二酸丁二醇二甘醇共聚酯(PBS-co-DEG)与热塑性淀粉(TPS)共混的复合膜,通过核磁共振氢谱仪、傅里叶变换红外光谱仪、凝胶渗透色谱仪、热重分析仪、紫外–可见分光光度计、偏光显微镜等对共聚酯的结构及复合膜的性能进行了表征和测试,采用N435脂肪酶对复合膜进行了降解实验。结果表明,随DEG含量的增加PBS-co-DEG/TPS复合膜的亲水性、光透过率和断裂伸长率均有所增加,热稳定性变化不明显;与PBS/TPS复合膜相比,PBS-co-DEG/TPS复合膜的酶降解速率显著提高。     

P(4HCA-co-DHCA)共聚物纳米粒子的制备与机理研究

由植物性单体4-羟基肉桂酸(4HCA)与3,4-二羟基肉桂酸(DHCA)的缩聚反应,制备了新型主链含芳环的共聚物P(4HCA-co-DHCA),在三氟乙酸(TFA)/N,N'-二甲基甲酰胺(DMF)的混合溶液中,通过离子化作用直接制得共聚物纳米粒子。用扫描电子显微镜(SEM)观察发现,该共聚物纳米粒子为单分散的球状结构;通过改变TFA和DMF的比例,详细地研究了纳米粒子的形成机理。     

无规共聚CPP薄膜专用树脂结构性能分析

从常规物性、链结构、相对分子质量、相对分子质量分布、结晶性能及流变性能对5种无规共聚聚丙烯流延膜(CPP)专用树脂进行对比分析。结果表明:无规共聚CPP专用树脂熔体流动速率一般在7 g/10 min左右,二元无规共聚聚丙烯的乙烯物质的量分数在4.5%~5.0%,且分子链序列结构数据较接近;FL7540为三元无规共聚物,具有最低的熔点及最高的弯曲模量;W0723F的结晶度最低,FL7540的晶体尺寸最小;W0723F晶型最不完善,RF402,FL7540结晶速度较快。流变性能分析表明这几种料的加工性能较为接近。     

纳米TiO2薄膜透光率及结构研究

采用溶胶一凝胶法在普通玻璃上制备了纳米TiO2薄膜．考察了聚乙二醇含量、溶胶液浓度、镀膜层数等各个因素对膜透光性能的影响．探讨了透光性能与光催化降解率的关系；利用XRD、SEM、光度法等对膜结构、表面形貌、透光率及催化活性进行了表征。由透光率与光降解率关系图可知．高透光率的薄膜具有强的光催化活性。     

基于金属浮栅层有机薄膜非易失性存储器的制备与表征

以聚甲基丙烯酸甲酯(PMMA)为栅介质,以并五苯为有机薄膜制备了有机薄膜非易失性存储器,研究基于热蒸发金属金浮栅层的存储行为。在2 s脉冲的偏压下,浮栅层通过充放电过程可导致明显的阈值电压偏移。在1 V的脉冲电压下可实现电荷的写入/擦除操作,在6 V的脉冲电压下可获得30.0 V的存储窗口。实验结果表明,基于金属浮栅层并以并五苯作为有机薄膜来制备非易失性存储器具有一定的研究价值和应用前景。     

钨酸锆薄膜样品高温衍射测试方法

基于不对称布拉格反射理论,以平行光掠入射方式配合普通X射线粉末衍射仪的高温样品台,研究了玻璃基钨酸锆薄膜样品的高温衍射测试方法,与聚焦光方式相比,减弱了玻璃基体的噪音影响,增加了衍射峰的强度,提高了谱图的可读性.XRD数据表明：钨酸锆薄膜样品的晶格常数随温度升高而变小,从25℃时的0.91791 nm逐步变小至600℃时的0.91243 nm.     

薄膜蒸发器温度场及膜内给热系数的数值模拟

应用CFD软件CFX4.4建立了薄膜蒸发器内水及粘性料液的传热计算模型,获得了沿轴向及膜厚方向的液膜平均温度分布,计算了各参数下加热段液膜内给热系数a. 结果表明,进料量及搅拌转速对各料液液膜温度分布及膜内给热系数影响显著. 不同粘度料液在不同操作条件下均存在同一最佳进料量,此时圈形波内截面平均速度 达到最大值, 相应的膜内给热系数a也达到最大值. 高转速或最佳进料量下,纯物质水流动边界层与膜厚之比及温度边界层与膜厚之比均最小,流动边界层与温度边界层存在内在联系. 传递边界层厚度严重影响液膜内温度分布及给热系数. 本研究各工况下,粘性料液尚未形成明显的温度边界层.     

热致变色VO2薄膜制备与影响相变因素

VO2具有优异的热致变色特性,已成为功能材料领域研究的热点.论文从VO2薄膜制备方法与薄膜相变特性影响因素两个方面,对其最新研究成果进行综述,总结了各种制备方法的优缺点,阐明了薄膜性能影响因素,并对其今后的研究与发展方向进行了展望.     

BaTiO3薄膜的Sol-gel法制备及其介电特性研究

以钛酸四丁酯和乙酸钡为主要原料,以乙二醇独甲醚为溶剂,采用溶胶凝胶法成功地配制出了BaTiO3溶胶,溶胶清晰稳定,保存时间长.并用XRD分析了沉积在Si(100)低阻硅片上的薄膜的结构,发现薄膜在600℃时结晶状态已良好.文中同时对薄膜的介电性质进行研究,并讨论了退火温度对薄膜介电性质的影响.     

TiO_2纳米多孔薄膜结构与光电化学性能相关性的研究

采用二步电压氧化法制备了两组孔径及孔密度不同的TiO_2纳米多孔薄膜,利用电化学测试方法对制备出的TiO_2纳米多孔薄膜的开路电位-时间曲线、交流阻抗谱图以及计时电流曲线进行了测试,研究了多孔薄膜材料的孔径及孔密度对材料光电化学性能以及比表面积的影响。结果表明,制备出的具有不同孔径和孔密度的试片在光照情况下的电化学反应电阻均明显下降,相关电化学反应更容易发生;增大薄膜材料的比表面积有利于提高其光电性能,性能最佳的薄膜材料的孔径为103 nm,孔密度为10×10~8个/cm~2。     

退火和老化气氛对铝酸钙玻璃上SiO_2薄膜性能影响

将用IAD法在CAB玻璃基体上沉积的SiO_2薄膜在600℃条件下部分进行退火,然后在不同湿度气氛中进行老化处理.利用分光光度计、纳米硬度计和扫描电镜研究了退火处理及不同老化气氛对SiO_2薄膜的光谱性能、硬度及摩擦性能的影响.实验结果如下:虽然退火和老化方式影响SiO_2薄膜的结构,但不同处理的SiO_2膜层表面摩擦系数均小于CAB玻璃基体,退火处理后的SiO_2薄膜硬度高于不退火处理的SiO_2薄膜硬度;SiO_2薄膜在可见光区内对CAB玻璃能够起到有效的增透作用;退火处理后红外透过率提高.实验结果表明CAB玻璃表面镀SiO_2薄膜在不损害光谱性能的同时可以起到有效地防护作用,显著提高其耐摩性能.     

Insight on Castor Oil Based Polyurethane and Nanocomposites: Recent Trends and Development

Castor oil has gained momentous attention as a valuable bio-based monomer and a potential alternative to the current petrobased polyol for synthesizing polyurethane due to the presence of inherent hydroxyl group. In spite of its huge potentiality very little has been reviewed regarding the development of polyurethane from castor oil. This review thus highlights the recent trends and development in the field of polyurethane and its nanocomposite based on castor oil including its biodegradability and weatherability studies. Further, this review also provides an insight regarding the utilization of castor oil based polyurethane and its nanocomposite for coating application.     

Regression Analysis of the Dielectric and Morphological Properties for Porous Nanohydroxyapatite/Starch Composites: A Correlative Study

This paper aims to investigate the dielectric properties, i.e., dielectric constant (ε′), dielectric loss factor (ε″), dielectric tangent loss (tan δ), electrical conductivity (σ), and penetration depth (D_p), of the porous nanohydroxyapatite/starch composites in the function of starch proportion, pore size, and porosity over a broad band frequency range of 5 MHz–12 GHz. The porous nanohydroxyapatite/starch composites were fabricated using different starch proportions ranging from 30 to 90 wt%. The results reveal that the dielectric properties and the microstructural features of the porous nanohydroxyapatite/starch composites can be enhanced by the increment in the starch proportion. Nevertheless, the composite with 80 wt% of starch proportion exhibit low dielectric properties (ε′, ε″, tan δ, and σ) and a high penetration depth because of its highly interconnected porous microstructures. The dielectric properties of the porous nanohydroxyapatite/starch composites are highly dependent on starch proportion, average pore size, and porosity. The regression models are developed to express the dielectric properties of the porous nanohydroxyapatite/starch composites (R² > 0.96) in the function of starch proportion, pore size, and porosity from 1 to 11 GHz. This dielectric study can facilitate the assessment of bone scaffold design in bone tissue engineering applications.     

热处理温度对Ba0.5Sr0.5TiO3薄膜结构与性能影响的研究

采用HPAgilent4294A阻抗分析仪、X衍射、扫描电镜等测试方法研究了热处理温度对BaxSr1-x，TiO3（BST）薄膜结构与性能的影响。当升／降温速率为0．5～1℃／min时，得到的薄膜表面均匀、无裂纹、孔洞。经过750℃退火处理后，薄膜的介电性能最佳，即具有较高的相对介电常数和较小的介质损耗。     

Effect of Blend Preparation on Electrical,Dielectric, and Dynamical‐Mechanical Properties of Conducting Polymer Blend: SBS Triblock Copolymer/Polyaniline

Conducting polymer blends based on styrene–butadiene–styrene (SBS) triblock copolymer and polyaniline doped with dodecylbenzene sulfonic acid (Pani.DBSA) were prepared by different procedures: mechanical mixing (MM) and ‘in situ’ polymerization (ISP) methods. The ISP blends exhibited higher levels of electrical conductivity, as compared to MM blends. The scanning electron micrographs of the ISP blend were characterized by the presence of microtubules, which favored the formation of the conducting pathways inside the SBS matrix. From dynamic mechanical and dielectric analysis, it was possible to suggest a higher interaction degree of the polyaniline with the polystyrene phase of the block copolymer. Blends prepared by ISP method displayed also higher dielectric constant and higher dielectric loss factor than blends prepared by MM method.

     

不同旋涂方式对铜锌锡硫硒薄膜及相应器件性能的影响

晶体质量是决定铜锌锡硫硒(Cu₂ZnSn(S,Se)₄, CZTSSe)吸收层薄膜吸收效率的关键,旋涂是溶液法制备CZTSSe吸收层的第一步,因此旋涂方式的选择至关重要。为了探究不同旋涂方式对CZTSSe吸收层薄膜质量和相应器件性能的影响,分别采用三组不同的旋涂方式制备铜锌锡硫(Cu₂ZnSnS₄, CZTS)前驱体薄膜及CZTSSe吸收层薄膜,并利用X射线衍射仪(XRD)、能谱仪(EDS)、显微拉曼光谱仪(Raman)、场发射扫描电子显微镜(FE-SEM)分析了不同旋涂方式对所制备的CZTSSe吸收层薄膜晶体结构、元素成分、相纯度、表面形貌的影响。同时,采用电流密度-电压(J-V)测试和外量子效率(EQE)测试对CZTSSe吸收层薄膜太阳电池的光电特性进行了表征。结果表明:旋涂7周期,且第一周期烘烤之前旋涂2次的效果最好,所制备的CZTS前驱体薄膜均匀,无裂纹,CZTSSe吸收层薄膜结晶度更高,薄膜表面更平整致密,晶粒大小更均匀,实现了9.63%的光电转换效率。通过对采用不同旋涂方式制备的器件的性能参数进行统计分析,得出新的旋涂方式可以提高CZTSSe薄膜太阳电池的可重复性,为将来可能的大规模商业化应用做铺垫。     

On the Optical Activity of Poly(l-lactic acid) (PLLA) Oligomers and Polymer: Detection of Multiple Cotton Effect on Thin PLLA Solid Film Loaded with Two Dyes

Optical rotatory dispersion (ORD) is a beautiful analytical technique for the study of chiral molecules and polymers. In this study, ORD was applied successfully to follow the degree of polycondensation of l-(+)-lactic acid toward the formation of poly(lactic acid) oligomers (PLAO) and high molecular weight poly(l-lactic acid) (PLLA) in a simple esterification reaction equipment. PLLA is a biodegradable polymer obtainable from renewable raw materials. The racemization of the intrinsically isotactic PLLA through thermal treatment can be easily followed through the use of ORD spectroscopy. Organic or molecular electronics is a hot topic dealing with the combination of π-conjugated organic compounds and polymers with specific properties (e.g., chirality) which can be exploited to construct optoelectronic devices, such as organic light-emitting diodes (OLEDs), organic photovoltaic (OPV) high efficiency cells, switchable chirality devices, organic field-effect transistors (OFETs), and so on. ORD spectroscopy was applied to study either the gigantic optical rotation of PLLA films, as well as to detect successfully the excitonic coupling, occurring in thin solid PLLA green film loaded with a combination of two dyes: SY96 (a pyrazolone dye) and PB16 (the metal-free phthalocyanine pigment). The latter compound PLLA loaded with SY96 and PB16 shows a really gigantic optical activity in addition to typical ORD signal due to exciton coupling and may be considered as a simple and easily accessible model composite of a chiral polymer matrix combined with π-conjugated dyes for molecular electronics studies.     

基于树脂膜溶渗经编多轴向复合材料成型及性能分析

详细阐述了四轴向经编玻璃纤维织物树脂膜溶渗成型工艺,测试了成型后的复合材料性能,并与同样条件下手糊成型工艺进行对比。结果表明:由于树脂膜溶渗成型工艺复合材料中的纤维体积含量要高于手糊成型工艺,因此其试样的断裂强力、断裂伸长率要高于手糊成型;另外,树脂膜溶渗成型复合材料试样沿不同取向断裂强力由高到低分别是经向、斜向、纬向;经真空辅助成型制备的材料相比手糊成型具有较优异的韧性。