侧氨基聚硅氧烷改性聚氨酯涂层剂的制备与性能

以侧氨基聚硅氧烷(SAPDMS)、聚四氢呋喃醚、聚乙二醇为混合软段,二羟甲基丙酸为亲水扩连剂,1,4-丁二醇为硬段调节剂,与异佛尔酮二异氰酸酯反应合成了水性有机硅改性聚氨酯(WSSPU),并以WSSPU为基础制备了防水透湿织物涂层剂。分别采用红外光谱、差热扫描量热仪、动态力学分析仪、正电子湮灭寿命谱等表征了WSSPU膜的组成与微观结构,考察了WSSPU膜的力学性能和涂层织物的防水透湿性能。结果表明,当侧氨基聚硅氧烷用量(质量比)< 15%时,可以制得稳定的乳液。聚硅氧烷改性后膜内部微相分离结构更加明显,自由体积空洞变大,透湿性能提高。     

聚硅氧烷改性水性聚氨酯的合成及其表面性能

以聚氧化丙烯二醇(PPG)、双羟基亲水性聚硅氧烷多元醇(UC3667)为软段,异佛尔酮二异氰酸酯(IPDI)、1,4-丁二醇(BDO)、二羟甲基丙酸(DMPA)、乙二胺(EDA)为硬段,制备了一系列聚硅氧烷改性水性聚氨酯(WPUs)。用DLS和FTIR表征了水性聚氨酯乳液粒径和膜结构。通过热重分析、拉伸测试、接触角测试、XPS对水性聚氨酯胶膜的性能进了测定。结果表明:随着聚硅氧烷加入量的增多,水性聚氨酯膜拉伸强度先增大后减小;且聚硅氧烷的加入提高了水性聚氨酯膜的热稳定性、断裂伸长率、接触角,降低了水性聚氨酯膜的表面能。当聚硅氧烷质量分数为5.0%时,胶膜表面的硅迁移量达到饱和,表面能为27.27 mJ/m~2。     

基于MIS改性的WPU/GO纳米复合乳液的研究

以2-氨基-4-羟基-6-甲基嘧啶(MIS)为改性剂,通过1-乙基-(3-二甲基氨基丙基)碳二亚胺盐酸盐(EDC·HCL)活化羧基制得MIS改性氧化石墨烯(MGO)分散液;并在水性聚氨酯乳化过程中引入MGO分散液制备水性聚氨酯/MIS改性氧化石墨烯(WPU/MGO)纳米复合乳液。通过红外光谱、热重分析、纳米粒度分析、扫描电子显微镜和力学分析对MGO,复合乳液和复合膜的结构与性能进行了表征。结果表明,当MGO的添加量为1%时,MGO在水性聚氨酯中均匀分散,纳米复合膜的杨氏模量、拉伸强度、断裂伸长率和热稳定性均有明显提高。     

聚硅氧烷-聚氨酯表面改性剂

采用聚硅氧烷 -聚氨酯共聚物作为表面改性添加剂对热塑性聚氨酯进行共混改性。接触角和ESCA测定结果表明 :聚硅氧烷向共混物表面迁移 ,富集在共混物表面 ,使其接触角增大 ,具有憎水性。     

环氧化合物改性侧链氨基聚硅氧烷的研究

以5种单官能缩水甘油醚——腰果酚缩水甘油醚（NC-513）、烯丙基缩水甘油醚（AGE）、苄基缩水甘油醚（692）、正丁基缩水甘油醚（660）及甲基丙烯酸缩水甘油酯（GMA）和侧链氨基聚硅氧烷为原料,通过环氧基与氨基的反应对侧链氨基聚硅氧烷进行改性。研究了不同反应条件下,改性聚硅氧烷的凝胶行为,表征了改性聚硅氧烷的结构。结果表明,NC-513与侧链氨基聚硅氧烷的反应活性最大;且室温以上时,改性聚硅氧烷凝胶的形成不受反应溶剂及原料反应官能团量之比的影响,所形成的凝胶为氢键物理交联;当温度升高时,会伴有羟基缩合的化学交联,烯键不与氨基反应。由于GMA中烯键和环氧基均与氨基反应,故形成化学交联凝胶。AGE、692、660改性聚硅氧烷在有溶剂的体系形成凝胶,在无溶剂情况下不形成凝胶。     

胺基化多孔再生纤维素膜的制备及其吸附性能的研究

在制备多孔再生纤维素膜的基础上,采用固-固相界面反应的TEMPO氧化法制备了氧化纤维素膜,通过乙二胺接枝改性成功制备了一种胺基化多孔再生纤维素膜。采用红外光谱、X-射线衍射、扫描电镜等对其结构进行表征,并研究了其对阴离子染料二甲酚橙的吸附性能。实验结果表明:改性纤维素膜上成功引入了胺基,且保留了多孔的纤维素膜结构;该改性膜对二甲酚橙具有良好的吸附效果,能够较快达到吸附平衡,其染料去除率高达92%。该吸附过程符合准二级动力学方程和Freundlich等温方程。     

高碘酸盐氧化纤维素与双醛纤维素衍生反应及应用研究进展

高碘酸盐氧化纤维素反应条件温和,反应生成的双醛纤维素含高反应活性的醛基,能够发生还原、磺化、氧化、胺化等反应,得到各种纤维素衍生物。该文主要介绍了高碘酸盐氧化纤维素的反应特征、双醛纤维素的衍生反应、高碘酸盐氧化法制备纳米纤维素的方法及双醛纤维素及衍生物在生物医药和废水处理等领域的应用。     

氨基氟硅氧烷改性大豆油基水性聚氨酯的制备

本文采用甲醇开环的大豆油基多元醇(MESO)、甲苯二异氰酸酯(TDI)和自制的氨基氟硅氧烷(AFSO)反应,成功制备出氨基氟硅氧烷改性大豆油基水性聚氨酯.通过红外、粒径、粘度、吸水率、静态接触角对AFSO改性水性聚氨酯乳液及其膜性能进行了测试.结果 表明,当AFSO含量从0wt％增加至13.3 wt％时,胶膜的表面水接...     

改性石墨烯/细菌纤维素复合导电纤维膜的制备研究

采用真空抽滤法制膜,并采用溶液还原法、蒸汽还原法以及先还原后制膜法3种工艺制备改性石墨烯/细菌纤维素复合导电纤维膜,采用扫描电镜(SEM)、X衍射(XRD)和Raman光谱对纤维膜材料的结构和性能进行表征,探讨了3种制膜工艺对复合导电纤维膜的表面电阻的影响。结果表明,通过SEM观察发现,采用溶液还原法和蒸汽还原法制备的复合导电纤维膜中石墨烯复合物(PNIPAM-rGO)与细菌纤维素较好结合,而先还原后制膜法制备工艺其结合效果较差;XRD证实了PNIPAM-rGO的存在几乎不影响细菌纤维素的结晶结构;Raman光谱较好地证实了PNIPAM-GO能充分还原成PNIPAM-rGO。通过比较导电纤维膜表面电阻发现,采用蒸汽还原法制备的导电纤维膜的导电性最佳。     

基于PEI改性的WPU/石墨烯纳米复合乳液的研究

使用超支化型聚乙烯亚胺(PEI)对氧化石墨烯(GO)进行改性制得改性氧化石墨烯分散液(GO-PEI);并在水性聚氨酯乳化过程中原位引入GO-PEI分散液,并还原制备水性聚氨酯/改性石墨烯纳米复合乳液(WPU/RGO-PEI)。通过红外光谱、紫外光谱、粒度分析、扫描电子显微镜和力学分析对GO-PEI、复合乳液和复合膜的微观结构与性能进行了表征。结果表明:RGO-PEI在水性聚氨酯膜中均匀分散,当RGO-PEI添加量为7%时模量提高12倍,添加量为15%时表面电导率达5.57×10^-4S/cm。     

双醛纤维素的制备及表征

以微晶纤维素(MCC)为原料,高碘酸钠为氧化剂,用正交实验考察了各种条件对氧化效率的影响。结果表明,影响醛基含量的顺序依次是投料比、反应时间、pH及反应温度。最佳氧化条件为:高碘酸钠和微晶纤维素投料质量比为1.0,反应温度30℃,pH=3,反应时间8 h。通过FTIR,XRD和SEM等对产物双醛纤维素在微粒形态、光谱特征、功能基团含量、晶体结构进行了表征。     

机械活化木薯淀粉制备双醛淀粉的研究

采用搅拌球磨机对木薯淀粉进行机械活化,以活化60 min的木薯淀粉为原料,NaIO4为氧化剂制备双醛淀粉,并以醛基摩尔分数为评价指标,考察活化时间、反应时间、反应温度、氧化剂用量、NaIO4浓度及体系pH等因素对木薯淀粉氧化反应的影响。结果表明,机械活化对木薯淀粉的氧化反应有显著的强化作用。双醛淀粉的醛基摩尔分数随活化时间的延长而增大;活化60 min的淀粉在反应时间90 min、反应温度30℃、n(NaIO4)∶n(AGU)=0.8∶1、NaIO4的浓度0.5 mol/L、体系pH=4的条件下制得的双醛淀粉x(醛基)=95.4%,而在相同条件下,由原木薯淀粉制得的双醛淀粉x(醛基)=58.2%。利用红外光谱仪、扫描电子显微镜和X射线衍射仪对产物的结构进行了表征。     

高碘酸钠氧化棉布纤维反应条件的研究

采用高碘酸钠对棉布纤维进行有限氧化,在棉布表面局部形成了双醛纤维素,为引入壳聚糖提供了活性部位。通过正交试验,初步确定棉布氧化反应最佳条件为:反应温度60℃,反应时间6 h,NaIO4浓度0.08 mol/L,pH值6,醛基含量超过180 mmol/L。     

Structural characterization of chitosan and oxidized carboxymethyl cellulose based freeze-dried films

The conversion of dihydroxyl groups to dialdehyde by periodate oxidation is a useful method widely used in derivatization of cellulose. Periodate oxidation is a highly specific reaction to convert 1,2-dihydroxyl groups to paired aldehyde groups without significant side reactions. This reaction cleaves the C2?CC3 bond; the resulting compound is the dialdehyde cellulose (DAC). These aldehyde groups of carboxymethyl cellulose interact with amino group of chitosan and their interaction results in the formation Schiff??s base with enhanced properties of both the polymers, i.e., of chitosan and carboxymethyl cellulose. Interaction of chitosan and oxidized carboxymethyl cellulose (OCMC) has been carried out with three combinations, i.e., 5, 10, and 15?wt% OCMC with rest of chitosan in 2% lactic acid solution. This new compound is covalently crosslinked which has been analyzed by various techniques like FTIR, TGA, XRD, and SEM.     

Preparation and Characterization of C10–C14 Alkyl Cellulose Ester Sulfate Surfactant

The aim of this work is to synthesize surfactants based on cellulose with different molecular weights. Raw cotton cellulose was tailored into cellulose segments with different molecular weights by a hydrothermal process, then the average degree of polymerization (DP) was determined by viscosimetry and the molecular weight distribution was estimated by gel permeation chromatography. The C₁₀–C₁₄ alkyl cellulose ester sulfate surfactants were prepared by hydrophilic sulfonation and hydrophobic esterification. The surface tension of the surfactants solution was obtained by the Wilhelmy plate method. Results showed that the cellulose segments presented a broader distribution compared with the raw material. The critical micelle concentration (CMC) value decreased from 1.08 to 0.86 wt% as the hydrophobic chain length was increased from 10 to 14. The CMC values of cellulose surfactants with C₁₄-acyl chloride hydrophobization decreased from 1.32 to 0.86 wt% as the DP was decreased from 2,700 to 296.     

“Dialdehyde Cellulose” Nanofibers by Electrospinning as Polyvinyl Alcohol Blends: Manufacture and Product Characterization

A nanofiber was obtained by electrospinning of “dialdehyde cellulose” (periodate-oxidized cellulose, DAC) and polyvinyl alcohol (PVA), using only water as the solvent. Celluloses of four different origins were fully oxidized with sodium periodate to water-soluble DAC. Aqueous solution of DAC showed inadequate spinnability regardless of the polymer concentration and the electrospinning conditions used. Addition of PVA improved the solution's viscoelasticity and, consequently, the solution's spinnability. We examined the effects of DAC/PVA composition and electrospinning parameters on fiber morphology. Highly homogeneous nanofibers were prepared from 1:1 up to 2:1 (weight) DAC/PVA blends while samples of lower viscosity or higher relative DAC contents resulted in continuous, beaded fiber networks. Characterization of the electrospun fabrics revealed a highly crosslinked DAC structure reinforced with PVA, strongly interacting through hemiacetal bonds and hydrogen bonding. Fluorescence labeling confirmed the presence of reactive aldehyde functionalities in the electrospun web. The versatile properties of DAC as reactive material can now be imparted on electrospun fiber and nanofiber material – which was not possible so far –further widening the application scope of this interesting cellulose derivative.     

Conductive polypyrrole composite films prepared using wet cast technique with a pyrrole–cellulose acetate solution

Conductive polypyrrole‐cellulose acetate films were prepared from cellulose acetate (CA) solution of pyrrole (Py) using wet cast method. In the composite films, Py was used as a solvent for CA which was dissolved with different concentration. Then, to prepare PPy–CA composite film, the Py viscous solution of CA was cast on glass plate and immersed in FeCl₃ aqueous solution. When the CA film was formed in the aqueous solution, the polymerized PPy particles having about 1 μm diameter were formed in composite film. The resultant composite films were characterized, showing good film fabrication and electrical conductivity of around 6.9 × 10^?4 to 3.6 × 10¹ S/cm. POLYM. ENG. SCI., 54:78–84, 2014. © 2013 Society of Plastics Engineers     

Properties of 2,3-dicarboxy cellulose combined with various metallic ions

2,3-Dicarboxy cellulose and partially oxidized 2,3-dicarboxy cellulose were prepared in good yields from the corresponding dialdehyde cellulose obtained by periodate oxidation of cellulose according to a modification of the method described by Hofreiter, Wolff, and Mehltretter [J. Am. Chem. Soc., 79 , 6457 (1957)]. The 2,3-dicarboxy cellulose oxidized to nearly 100% oxidation level was completely soluble in water, but the 2,3-dicarboxy cellulose of 70% oxidation level was not. The former 2,3-dicarboxy cellulose took up various metallic ions other than alkali metals to form a precipitate or solid. The metal contents taken up corresponded to the theoretical values calculated as combined in the form of metallic salt of the carboxylic acid group. 2,3-Dicarboxy cellulose combined with metallic ions such as copper, cobalt, and nickel ions gave viscous, gel-like products, which solidified when exposed to air. The properties of products combined with such metallic ions are discussed.     

Novel surface modification of cellulose film by heat‐set finishing method using poly(ethylene glycol)‐coated polystyrene nanospheres

The nanosphere having hydrophobic backbone and hydrophilic branches was used as the agent for the surface modification of a cellulose film. They were obtained by dispersion copolymerization of styrene (St) and poly(ethylene glycol) (PEG) macromonomers in an ethanol/water solution at 60°C by using a free‐radical initiator. The PEG‐coated polystyrene (PSt) nanosphere–water dispersions were prepared at concentrations of 0.1, 0.2, 0.5, and 1.0% (w/v). A measure of 1 mL of the dispersion was poured over the cellulose film, cut into a strip of 5 × 5 cm². The film was pressed by plates heated at 200°C with 6.8 g/cm² pressure for 2 min to melt PSt nanospheres and fix them on the cellulose film. The morphology of the film surface was also observed by a scanning electron microscopy (SEM). The resulting modified surface was characterized by X‐ray photoelectron spectroscopy (XPS). The contact angle, the moisture absorption, and the leakage of electrostatic charge from the film were studied. The surface of the film treated with the dispersion had high water‐repellency, although the bulk properties did not change. It was found that the dispersion was effective in making the cellulose surface hydrophobic. The surface modification of cellulose film was successful by using this simple method. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1516–1523, 1999     

纤维素―铝酸锶复合膜的制备及表征

将微晶纤维素溶解于氯化1-正丁基-3-甲基咪唑([Bmim]Cl)离子液体中,加入铝酸锶荧光粉,然后流延成膜,制备得到了纤维素―铝酸锶复合膜。利用红外光谱、X射线衍射、热重分析、扫描电镜和荧光发射光谱对复合膜进行了表征。结果表明,铝酸锶荧光粉在纤维素膜中分布均匀,铝酸锶荧光粉和纤维素之间存在着一定的相互作用,纤维素对荧光粉体发光影响较小。