共查询到20条相似文献，搜索用时 15 毫秒
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In this work, the kinetics of the polyvinyl butyral (PVB) synthesis reaction catalyzed by the deep eutectic solvents (DESs) at the low-temperature stage was studied to control the particle size of PVB resin and optimize its synthesis process. The effects of stirring speed, the concentration of polyvinyl alcohol (PVA), catalyst dosage, and temperature on the synthesis reaction of PVB were investigated. The data obtained from kinetic experiments at 283.15–298.15 K were fitted with the shrinking core models, and the results showed that the model controlled by internal diffusion fitted well with the experimental data. The internal diffusion coefficient, DA, of n-butanal in the product layer was further calculated by the obtained model parameters, and it was applied to predict the synthesis reaction of PVB at different concentrations of n-butanal. The results indicated that the shrinking core model controlled by internal diffusion is suitable to describe the kinetics of the PVB synthesis reaction. DES played a dual role in catalysis and dispersion in the synthesis of PVB, and it was a green catalyst with good potential for PVB industrial applications. 相似文献
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Sun Theo Constan Lotebulo Ndruru;Muhammad Yogi Saputra;Zurriyati Zurriyati;Atika Trisna Hayati;Risda Adriana;Muhammad Al Muttaqii;Edi Pramono;Sonny Widiarto;Marvin H. Pasaribu;Bernadeta Ayu Widyaningrum;Robertus Wahyu N. Nugroho;Deana Wahyuningrum;I Made Arcana; 《应用聚合物科学杂志》2024,141(48):e56050
As a key component for the future high-safety lithium batteries, solid polymer electrolyte (SPE) is gaining an attractive momentum toward large-scale production due to their remarkable compatibility and processability with electrodes. Further, their excellent performance can be improved using the potential use of plasticizers. A deep eutectic solvent (DES) synthesized from choline chloride (ChCl) and citric acid monohydrate (CAM) demonstrates a promising plasticizer to design good SPE membranes along with poly (vinyl alcohol) (PVA). The changes in the surface chemistry of PVA-based membranes, as determined by Fourier transform infrared (FTIR) spectroscopy, confirm the success of DES-plasticizing effect, where detected by wavenumber shifting around main functional groups such as OH, CO, and COC. Following this, EIS characterization on electrical properties reveals the role of 30 wt% DES in improving the ionic conductivity, with the highest ionic conductivity equivalent to 4.66 × 10−4 S cm−1 and the crystallinity index as high as 41.09%. The presence of LiClO4 and DES significantly reduces mechanical performance, and glass transition of PVA-based membranes, as characterized by tensile testing and differential thermal analysis/thermogravimetric analysis. Thus, the presence of DES in PVA and LiClO4 matrices could open another window for designing SPE with novel physicochemical properties. 相似文献
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Dr. Lei Huang Jan Philipp Bittner Dr. Pablo Domínguez de María Dr. Sven Jakobtorweihen Prof. Dr. Selin Kara 《Chembiochem : a European journal of chemical biology》2020,21(6):811-817
The use of oxidoreductases (EC1) in non-conventional reaction media has been increasingly explored. In particular, deep eutectic solvents (DESs) have emerged as a novel class of solvents. Herein, an in-depth study of bioreduction with an alcohol dehydrogenase (ADH) in the DES glyceline is presented. The activity and stability of ADH in mixtures of glyceline/water with varying water contents were measured. Furthermore, the thermodynamic water activity and viscosity of mixtures of glyceline/water have been determined. For a better understanding of the observations, molecular dynamics simulations were performed to quantify the molecular flexibility, hydration layer, and intraprotein hydrogen bonds of ADH. The behavior of the enzyme in DESs follows the classic dependence of water activity (aW) in non-conventional media. At low aW values (<0.2), ADH does not show any activity; at higher aW values, the activity was still lower than that in pure water due to the high viscosities of the DES. These findings could be further explained by increased enzyme flexibility with increasing water content. 相似文献
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研究了氯化铬(CrCl3·6H2O)和氯化镍(NiCl2·6H2O)浓度和存在形式对氯化胆碱-乙二醇(ChCl-EG)低共熔溶剂的黏度和电导率的影响。电喷雾质谱(ESI-MS)分析结果表明,在溶解有CrCl3?6H2O和NiCl2?6H2O 的ChCl-EG(ChCl-EG-NiCl2·6H2O-CrCl3·6H2O)溶液中出现了配阴离子[Cr(H2O)2Cl4]–和[Ni(H2O)2Cl4]2-。由此可以推断,Cr3+(或Ni2+)的两个d轨道、4s 和4p轨道发生d2sp3杂化,形成6个等同的杂化轨道,接受6个配体(Cl-和H2O)形成阴离子配合物。该溶液的电导率随温度的升高而增大,随总金属离子浓度的增大而减小。此外,溶液黏度随温度和总金属离子浓度的变化趋势与电导率相反。这主要是由于镍和铬配离子的形成改变了溶液中的离子组成。 相似文献
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Recent advances in novel electroactive devices have placed new requirements on material development. High-performance dielectric elastomers with good mechanical stretchability and high dielectric constant are under high demand. However, the current strategy for fabricating these materials suffers from high cost or low thermal stability, which greatly hinders large-scale industrial production. Herein, we have successfully developed a novel strategy for improving the dielectric constant of polymeric elastomers via deep eutectic solvent inclusion by taking advantage of the low cost, convenient and environmentally benign synthesis process and high ionic conductivity from deep eutectic solvents. The as-prepared composite elastomers showed good stretchability and a greatly enhanced dielectric constant with a negligible increase in dielectric dissipation. Moreover, we have proven the universality of our strategy by using different types of deep eutectic solvents. It is believed that low-cost, easy-synthesis and environmentally friendly deep eutectic solvents including composite elastomers are highly suitable for large-scale industrial production and can greatly broaden the application fields of dielectric elastomers. 相似文献
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以铜粉和硫粉为原料,在摩尔比为0.48:0.32:0.2的乙酰胺,尿素,硝酸铵三元低共熔溶剂中通过单质直接反应合成了纳米CuS。通过XRD、SEM、EDS和UV-Vis DRS等手段进行了表征,XRD、EDS表明产品为纯净的CuS晶体。SEM显示产品是由纳米片交错连结而成的球体结构。UV-Vis DRS表明产品的禁带宽度为1.86 e V。测试产品的光催化降解染料性能,光照100 min后亚甲基蓝(10 mg/L)的降解率可达到100%。表明CuS具有良好的光催化活性。 相似文献
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Dorota Skowro&#x;ska Katarzyna Wilpiszewska 《International journal of molecular sciences》2022,23(24)
In the paper, the method of obtaining the potato starch nanocomposites plasticized with a deep eutectic solvent is described. The deep eutectic solvent based on choline chloride and malic acid (CM, molar ratio 1:1) was used as the plasticizer. The effect of the sodium and calcium montmorillonite (MMTNa, MMTCa respectively) addition on the properties of potato starch films was investigated. The thermal, mechanical, and barrier properties were determined. Moreover, a moisture absorption test was performed. The starch gelatinization temperature increased in the presence of montmorillonite. The values of glass transition determined by DMTA depended on the nanofiller type. For the systems containing MMTCa, they generally decreased with its content (although still lower than reference samples). The obtained nanocomposites showed improved mechanical and barrier properties. The highest values of tensile strength and Young’s modulus were noted for the system containing 1% MMTNa. The XRD revealed that only the films with MMTNa exhibited intercalation. The homogeneity of the samples decreased with increasing nanofiller concentration. This was probably due to the occurrence of choline chloride-montmorillonite interactions, which were more favored than clay-starch interactions. 相似文献
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分析了醋酸乙烯衍生物聚乙烯醇、醋酸乙烯一乙烯共聚物VAE乳液和EVA树脂、聚乙烯醇缩丁醛的国内市场形势。 相似文献
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Deep eutectic solvents (DESs) are a kind of potential lixiviant for extraction processing. Unlike conventional ionic liquids (ILs), DESs are relatively cheap and environmentally friendly. Herein, three different ChCl-based DESs, namely, choline chloride/urea, choline chloride/ethylene glycol, as well as choline chloride/propandioic acid, were synthesized and used to enhance bitumen recovery from oil sand by petroleum ether extraction. The results showed a multiphase system formed after mixing the components at ~25°C, consisting of sands and clays, a DES layer, and a petroleum ether layer containing the bitumen. These DESs were immiscible with bitumen or petroleum ether. Coupled with a density difference, a clear phase separation was presented between the bitumen–petroleum ether mixture and DES. The DES functioned as a separating agent, keeping the petroleum ether–bitumen mixture and spent sand apart from each other. The results showed that the bitumen recovery was increased by ~12% compared with that without the DESs. We deduced that the enhancement in the separation may result from the reduction of adhesion between bitumen and sand by the DESs. The ChCl-based DESs and petroleum ether could be readily recycled to reduce industrial costs. After 10 cycles, the bitumen recovery remained above 86%. 相似文献
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W. J. Pech-Rodríguez E. Rocha-Rangel Carlos Adrian Calles-Arriaga G. Vargas-Gutiérrez F. J. Rodríguez-Varela 《应用陶瓷进展》2018,117(8):461-467
ABSTRACTThe present work discusses the electrophoretic deposition (EPD) of copper–carbon nanotubes (Cu–CNTs) composite coatings in a Deep Eutectic Solvent (DES) media, using a non-symmetric deposition process. A Taguchi experimental design is implemented in order to assess the effect of the different parameters on the microstructural characteristics of the coatings. The analysis of the design of experiments (DOE) is performed with the signal to noise (S/N) ratio and the analysis of variance. The results clearly reveal that the time of deposition is the most influential parameter on crystallite size, whereas the asymmetric factor has the highest effect on the preferential deposition of Cu or C and thus on the chemical composition. It is therefore concluded that by changing some of the parameters, EPD can be implemented to develop nanostructured composite coating having a desired crystallite size and morphology. 相似文献
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Yan Qi;Junbiao Peng;Chunsheng Zhang;Danling Wang;Yihu Song;Qiang Zheng; 《应用聚合物科学杂志》2024,141(39):e56006
Rubber nanocomposites exhibit strain softening under large-amplitude oscillation shear and large-strain cyclic tension while the softening behaviors are hard to regulate in industry. Herein, an oligomer deep eutectic solvent (DES) synthesized from polyethyleneglycol and tetrabutylammonium bromide is used to mediate the vulcanization and softening behaviors of natural rubber (NR) gums and their nanocomposites. The results show that DES could accelerate NR vulcanization and improve crosslinking density. For the hydrophilic silica nanocomposites, DES could greatly reduce tanδ and weaken weak strain overshoot accompanying Payne and lower percentages damping accompanying Mullins effects. The effects in nanocomposites filled with hydrophilic/hydrophobic silica and carbon black are investigated and compared. The investigation provides a new way for tailoring elasticity and dissipation of vulcanizate nanocomposites filled with hydrophilic silica. 相似文献
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采用季铵盐与酚形成低共熔溶剂(DES)从含酚的混合物中萃取分离酚是一种有效的油酚分离方法, 然而分离过程中, 中性油的夹带会影响分离效率。以含苯酚200 g·L-1的甲苯溶液作为模拟油酚混合物, 氯化胆碱(ChCl)作为分离剂, 研究了氯化胆碱的加入量、萃取温度(25～55℃)及模拟油中直链烷烃的浓度等因素对酚的萃取分离及中性油夹带的影响。结果表明, 随着ChCl加入量增大, 酚萃取率升高, 中性油的夹带量减少;ChCl过量时, 酚的萃取量恒定且达到极大值, 中性油夹带量恒定且夹带量最小;萃取温度对酚的萃取率影响不大, 对中性油的夹带量在ChCl加入量不足时随温度升高而增多, 当ChCl加入量足量时与温度变化关系不大;模拟油中直链烷烃的浓度不影响萃取效率, 浓度越高, 甲苯夹带越少。以ChCl萃取含苯酚200 g·L-1的甲苯溶液, 在萃取温度25℃、ChCl加入量大于0.6(与酚的摩尔比)的条件下, 苯酚萃取率达95%, 甲苯夹带率为15%, 70℃条件下氮气吹扫60 min内可将DES中甲苯完全去除。 相似文献
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Lignin readily dissolves in a deep eutectic solvent (DES) composed of ZnCl2/acetamide 1:3 M ratio in concentrations up to 16.7 wt %, and upon addition of water, two fractions were obtained; one composed of lignin with low-molecular weight that remained dissolved in the DES/water mixture, whereas the other fraction of lignin with higher molecular weight (regenerated lignin, RL) was regenerated by precipitation. Both the RL fraction and the whole solution of lignin in DES were used to replace part of phenol (20 wt %) in the condensation of phenol and formaldehyde to introduce biomass in the resulting resins. The lignin treatment that produced the higher yield of RL consisted of lignin/DES ratio of 1:10 (w/w) stirred for 4 h at 100 °C. By using 13C NMR spectroscopy, a preferential cleavage of the S unit of lignin during DES treatment was identified. The modified phenol-formaldehyde resin (RLPF) containing the RL exhibited higher bonding strength (1.28 ± 0.16 MPa) and shorter Sunshine gel time (557 s) than PF (587 s), showing that the RL helps to improve the polycondensation process. The resin modified with the whole solution of lignin in DES exhibited the shortest Sunshine gel time due to the effect of zinc(II) accelerating the curing process. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48385. 相似文献
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以甲醇为溶剂,以环氧树脂为引发剂,乙酸乙烯酯与甲醇的质量比为25∶3.96,反应温度为(65±2)℃,引发剂用量为0.080 2 g,反应4.5 h,以溶液聚合法制备粘均相对分子质量为1.95×105的聚醋酸乙烯酯,经醇解得到无毒的聚乙烯醇,产品经UV,FTIR,1H NMR谱进行确认和结构分析。讨论了反应温度、反应时间、引发剂用量、原料质量比对醋酸乙烯酯相对分子质量的影响。 相似文献
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高聚合度的聚醋酸乙烯酯醇解制备聚乙烯醇,由于其相对分子质量较大,所以研究其醇解工艺显得尤为必要.就影响醇解工艺的因素,如醇解温度、醇解时间、催化剂浓度等进行了探讨,得出了高聚合度PVAc醇解最佳工艺. 相似文献
