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1.
研究比较线型聚酯胺和超支化聚酯胺作为添加剂用于静电纺丝时,对低浓度聚甲基丙烯酸甲酯溶液可纺性的改善效果及其机理.结果表明,只需加入1wt%的添加剂,无论是线型的还是超支化聚酯胺均能够提高低浓度聚甲基丙烯酸甲酯溶液的可纺性,得到无"串珠"结构的均匀纤维,其直径比不加添加剂而在高浓度纺丝时得到的均匀纤维细很多.通过溶液性能的测试,发现提高可纺性的原因均是由于溶液电导率的提高.超支化聚酯胺因其多枝的结构而含有较多的极性端基,致使本身电导率较高,因而对可纺性的改善效果好于线型聚酯胺.  相似文献   

2.
<正> 酚醛Novolak树脂的溶液性质已有不少研究,但对由槚如坚果壳液(Cashew NutShell liquid CNSL,主要成分为改性的酚醛树脂溶液性质研究得不多。本文用粘度、气相渗透压和红外光谱法等研究了CNSL改性酚醛树脂在丙酮中的溶液性质,订定了Mark-Houwink方程中的参数K和α,以及根据α和Huggins常数K′讨论了CNSL改性酚醛树脂在丙酮中的形态。  相似文献   

3.
芹菜、草莓基质对甲胺磷等4种有机磷农药测定的影响   总被引:1,自引:0,他引:1  
研究芹菜、草莓基质对甲胺磷、乙酰甲胺磷、氧化乐果、毒死蜱4种有机磷农药检测的影响。利用样品基质溶液配制标准样品,对比草莓、芹菜样品、丙酮溶液中4种农药的保留时间、峰形、峰面积。结果发现DB–5MS色谱柱上,丙酮溶液、芹菜基质、草莓基质中甲胺磷、乙酰甲胺磷、氧化乐果色谱峰出峰时间不完全重合,保留时间最大漂移0.1 min。丙酮溶剂、芹菜基质较草莓基质中的甲胺磷、乙酰甲胺磷、氧化乐果更容易出现峰拖尾现象,且芹菜基质溶液中相同浓度的甲胺磷、乙酰甲胺磷峰面积分别约是草莓基质溶液中的75%,90%。毒死蜱的保留时间、峰形、响应面积在草莓基质、芹菜基质、丙酮溶液中基本一样。  相似文献   

4.
再生丝素蛋白水溶液的干法纺丝   总被引:1,自引:0,他引:1  
以高浓度再生丝素蛋白水溶液为纺丝液,采用自制毛细管纺丝装置制备了再生丝素蛋白纤维.探讨了丝素蛋白分子量、pH、金属离子及纺丝工艺参数对溶液可纺性及纤维力学性能的影响.结果表明:当pH为5.2~6.0时,纺丝液表现出良好的可纺性,尤其以pH=6.0、Ca2+浓度为0.3 mol/L的纺丝液可纺性最佳.在最佳纺丝条件下(纺丝管长径比为133;卷绕速率为30mm/s)制得的纤维力学强度最高约为45.5 MPa.  相似文献   

5.
以聚对苯二甲酸二醇酯(PET)无纺布为基底,聚偏氟乙烯(PVDF)纳米纤维为支撑层,聚乙烯醇(PVA)纳米纤维膜为分离层,采用静电纺丝法制备超滤膜,并用水/丙酮混合溶液对复合纳米纤维膜表面进行溶液处理,再加入戊二醛交联改性得到致密分离层.采用扫描电子显微镜(SEM)和红外光谱(FTIR)表征了复合超滤膜的表面,用水接触角(WCA)表征复合超滤膜的亲水性.在0.02 MPa恒压下死端过滤油/水乳液,测试复合超滤膜的过滤性能.结果表明,最优条件下制备的复合超滤膜死端过滤油/水乳液的通量为(42.50±4.78)L/(m~2·h),截留率达到(95.72±0.33)%;循环使用5次后,依然具有较好的过滤性能,常压下死端过滤复合超滤膜的纯水通量为(3469±28)L/(m~2·h).  相似文献   

6.
醋酸纤维素是目前世界上应用最为广泛的反渗透膜材料,醋酸纤维素-丙酮溶液法成膜是最简单、最经济的成膜疗法,但目前有关其铸膜溶液的研究还远远不够。添加剂是铸膜溶液的重要组成之一,对于分离膜微孔结构的形成有着重要的意义。为此本文采用水、甲酰胺、磷酸、甘油、正丙醇作为添加剂,研究了它们对于醋酸纤维素-丙酮溶液结构与性质的影响。实验部分原料采用上海群力塑料厂生产的醋酸纤维素(CA),取代度为2.42,并采用去离子水和各种化学纯试剂:丙酮、磷酸、甲酰胺、正丙醇和甘油。IR分析采用Analect RFX-65型红外光谱仪,傅里埃变换迭加64次。  相似文献   

7.
采用反应挤出法制备了一系列不同组成的聚(对亚苯基苯并二唑/3-氨基-4羟基苯甲酸盐酸盐)(PBO-b-ABPBO)多嵌段共聚物,用傅立叶红外(FT-IR),广角X射线衍射(WXRD)对其结构进行了表征,并用热重分析(TGA)对其热性能进行分析,另外用压差式毛细管流变仪对PBO-b-ABPBO溶液的剪切流变性能进行了研究.结果表明:PBO-b-ABPBO溶液在流动性和可纺性方面较PBO溶液有较大改善,尽管PBO-b-ABPBO纤维的热性能和力学性能比PBO纤维略有下降.  相似文献   

8.
本文采用 IR、粘度测量、Huggins 方程和 MCALLISTER 方程表征,计算机拟合非线性方程组等方法研究了醋酸纤维素—丙酮溶液中各种添加剂对醋酸纤维素和丙酮的相互作用。结果表明,添加剂与丙酮有一定的相容性或部份相容性,与醋酸纤维素有一定的氢键或亲核作用。添加剂与醋酸纤维素之间的相互作用强烈地影响着醋酸纤维素的形态结构和分子之间的相互作用力。  相似文献   

9.
脱乙酰甲壳质溶液的粘度及其稳定性   总被引:1,自引:0,他引:1  
本文研究了脱乙酰甲壳质(CTS)的甲酸、乙酸以及甲、乙酸的异丙醇、乙醇、丙酮溶剂体系的溶液粘度及稳定性,并从溶液的稠度指数K和流动行为指数n来考察其增稠能力和溶液性质。实验表明,含有异丙醇和乙醇溶液的粘度,比不含有机溶剂的溶液的粘度高,而含有丙酮的则较低。有机溶剂的加入,对溶液的稳定性没有明显的影响,CTS甲酸系统的溶液比乙酸系统的溶液具有较好的稳定性。分子量为5.6×10~5CTS的增稠能力不及部分水解聚丙烯酰胺,但优于卡拉胶。CTS溶液属假塑性流体,其K值随溶液存放时间延长而下降,但n值上升,并接近于1。实验发现,抗氧剂维生素C不仅不能增加CTS溶液的稳定性,且对CTS有明显的促进降解作用。  相似文献   

10.
采用溶胶-凝胶法制备了TiO2-SnO2复合凝胶,利用XRD、UV、IR谱对其结构进行了表征,研究了复合凝胶的组成对水、乙醇、丙酮、氨水蒸气平衡吸附量的影响,以苯酚溶液为模拟污染物测定了复合凝胶的光催化降解能力.实验结果表明,组成为n(TiO2)∶SnO2=80%∶20%的复合凝胶具有最强的吸附和光催化活性,对水蒸气、乙醇、丙酮气体的吸附以及对苯酚溶液的光催化降解能力均高于其它组成的复合凝胶.  相似文献   

11.
A poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) fibrous surface with various bead-on-string structures was fabricated by electrospinning. PHBV was electrospun at various concentrations and then CF4 plasma treatment was employed to further improve the hydrophobicity of the PHBV fiber surfaces. The surface morphology of the electrospun PHBV mats was observed by scanning electron microscopy (SEM). The surface properties were characterized by water contact angle (WCA) measurements and X-ray photoelectron spectroscopy (XPS). The surface morphology of the electrospun PHBV fibrous mats with the bead-son-string structure varied with the solution concentration. The WCA of all of the electrospun PHBV mats was higher than that of the PHBV film. In particular, a very rough fiber surface including porous beads was observed when PHBV was electrospun from the solution with a concentration of 26 wt%. Also, its WCA further increased from 141 degrees to 158 degrees after CF(4) plasma treatment for 150 s. PHBV can be rendered superhydrophobic by controlling the surface morphology and surface energy, which can be achieved by adjusting the electrospinning and plasma treatment conditions.  相似文献   

12.
Based on the Euler-Lagrange equation for ion density distribution in an inhomogeneous, charged, and hard-sphere fluid, a novel method is proposed to determine the interaction pressure between charged plates. The resulting expression is a sum of distinct physical contributions to the pressure, which involves different contributions to the single-particle direct correlation function. It can, therefore, be conveniently used in any density functional approach to facilitate analysis of the pressure components. In this study, the so-called fundamental measure theory (FMT)∕weighted correlation approach (WCA) approach is applied to estimate both the hard-sphere and the electric residual contributions to the single-particle direct correlation function, upon the calculation of the ionic density profiles between charged plates. The results, against the Monte Carlo simulations, show that the FMT∕WCA approach is superior to the typical FMT∕mean spherical approximation approach of the density functional theory in predicting the interaction pressure between charged plates immersed in an electrolyte solution upon various conditions in the primitive model. The FMT∕WCA approach can well capture the fine features of the pressure-separation dependence, to reproduce not only the shoulder shape and the weak attractions in monovalent electrolytes but also the strongly oscillatory behavior of pressure in divalent electrolytes where pronounced attractions are observed. In addition, it is found that the FMT∕WCA approach even has an advantage over the anisotropic, hyper-netted chain approach in that it agrees with the Monte Carlo results to a very good extent with, however, much less computational effort.  相似文献   

13.
Hydrophobins are structural proteins produced by filamentous fungi that are amphiphilic and function through self-assembling into structures such as membranes. They have diverse roles in the growth and development of fungi, for example in adhesion to substrates, for reducing surface tension to allow aerial growth, in forming protective coatings on spores and other structures. Hydrophobin membranes at the air-water interface and on hydrophobic solids are well studied, but understanding how hydrophobins can bind to a polar surface to make it more hydrophobic has remained unresolved. Here we have studied different class II hydrophobins for their ability to bind to polar surfaces that were immersed in buffer solution. We show here that the binding under some conditions results in a significant increase of water contact angle (WCA) on some surfaces. The highest contact angles were obtained on cationic surfaces where the hydrophobin HFBI has an average WCA of 62.6° at pH 9.0, HFBII an average of 69.0° at pH 8.0, and HFBIII had an average WCA of 61.9° at pH 8.0. The binding of the hydrophobins to the positively charged surface was shown to depend on both pH and ionic strength. The results are significant for understanding the mechanism for formation of structures such as the surface of mycelia or fungal spore coatings as well as for possible technical applications.  相似文献   

14.
ICP刻蚀硅模板用于PDMS规则超疏水表面的制作   总被引:2,自引:0,他引:2  
张润香  张玉龙  林华水 《电化学》2007,13(3):264-268
在ICP(inductively coupled plasma)刻蚀后的硅模板上复制聚二甲基硅氧烷(PDMS),经剥离得到含有一定尺寸的规则微柱阵列疏水表面.实验表明,当微柱高度较小时,微柱高度和边长对接触角有正影响,而间距则呈负影响;但如微柱高度较大,则高度对接触角的影响趋小,而边长呈负影响.间距对接触角的影响表现复杂.微柱间距6μm,边长14μm和高14μm微柱阵列的PDMS表面,静态接触角最大,约151°.  相似文献   

15.
Superhydrophobic cerium oxide film was introduced to aluminum substrate by an in‐situ growth process and surface modification. Different molar ratios between Ce(NO3)3 · 6H2O and C6H12N4 were involved in this research. The morphologies, chemical compositions and wetting properties of the films were analyzed by scanning electron microscopy (SEM), energy dispersive X‐ray detector, Fourier transfer infrared spectrometer and water contact angle (WCA) measurement, respectively. A great WCA of 158.8o with a low angle hysteresis of about 3o was obtained. Combination of uniform hierarchical micro‐nanostructure as revealed by SEM together with the hydrophobic alkyl groups from stearic acid was found to be responsible for the superior superhydrophobic property. The corrosion resistance performance of the superhydrophobic surface was evaluated by immersing in sodium chloride aqueous solution, the WCA kept as high as 152.1o after immersion for 21 days, indicating our superhydrophobic surfaces had high chemical stability and durability in corrosive medium. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

16.
菠菜叶绿素的浸提和协同萃取反应   总被引:27,自引:0,他引:27  
有机溶剂;菠菜叶绿素的浸提和协同萃取反应  相似文献   

17.
通过溶液聚合法合成了聚(丙烯酸六氟丁酯-co-甲基丙烯酸)(P(HFBA-co-MAA))和聚(甲基丙烯酸十二氟庚酯-co-甲基丙烯酸)(P(DFHMA-co-MAA))羧基氟碳共聚物. 静电纺丝实验结果表明,随着 MAA 用量的减少,两种氟碳共聚物的可纺性逐渐变差,相应的纺丝液的浓度也逐渐降低,所用溶剂的极性和沸点呈现降低的趋势;当配制纺丝液所用低沸点溶剂丁酮用量增大时,所得纤维的直径呈增加趋势;P(DFHMA-co-MAA) 的可纺性优于 P(HFBA-co-MAA). 采用两步法在 P(DFHMA-co-MAA)共聚物纤维表面制备光催化剂 ZnS,XPS 结果表明锌离子先与共聚物纤维表面的羧酸根离子络合,然后络合的锌离子再与硫源 TAA 反应形成 ZnS. MAA 用量高的共聚物纤维表面形成的 ZnS 量与粒子尺寸较大,MAA 用量为 10 wt% 时,共聚物纤维表面形成了纳米级的 ZnS 粒子,通过紫外降解实验和红外分析表明制备的 ZnS/P(DFHMA-co-MAA)纤维复合物具有很好的耐紫外光降解性能.  相似文献   

18.
The photochemical processes of aromatic amino acids were investigated in aqueous solution using acetone as photosensitizer by KrF (248 nm) laser flash photolysis. Laser-induced transient species were characterized according to kinetic analysis and quenching experiments. The intermediates recorded were assigned to the excited triplet state of tryptophan, the radicals of tryptophan and tyrosine. The excited triplet state of tryptophan produced via a triplet-triplet excitation transfer and the radicals arising from electron transfer reaction has been identified. Neither electron transfer nor energy transfer between triplet acetone and phenylalanine can occur in photolysis of phenylalanine aqueous solution which contains acetone. Furthermore, triplet acetone-induced radical transformation: Trp/N-Tyr→Trp-Tyr/O was observed directly in photolysis of dipeptide (Trp-Tyr) aqueous solution containing acetone, and the transformation resulting from intramolecular electron transfer was suggested.  相似文献   

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