Synthesis of PDMS-PS IPN Pervaporation Membrane for Pervaporation Recovery of Butanol

Polydimethylsiloxane(PDMS)-polystyrene(PS) interpenetrating polymer network(IPN) was prepared and characterized by FTIR, TGA, WCA, swelling experiments, and SEM. The IPN was used for pervaporation(PV) recovery of butanol. Both the permeation flux and separation factor increased with feed temperature, and both water and butanol fluxes increased with feed concentration, while no obvious effect of concentration on separation factor was found. Through the formation of IPN structure, the total flux of PDMS-PS IPN pervaporation membrane increased greatly with the decrease of separation factor. At the feed temperature of 60 °C, the IPN membrane obtained a total flux of 920.3 g/m~2 h with a separation factor of 9.5.     

Preparation of <Emphasis Type="Italic">γ</Emphasis>-methacryloxypropyl Trimethoxy Silane Cross-linked PDMS Membrane for Pervaporation Recovery of Butanol

The present study aimed to improve the pervaporation (PV) performances of polydimethylsiloxane (PDMS) membranes by using special cross-linkers. The γ-methacryloxypropyl trimethoxy silane (KH-570) cross-linked PDMS membranes were fabricated and characterized by FTIR, TGA, WCA, DSC, SEM, and swelling properties. Experimental results showed that the separation factor of the membrane increased slightly with the feed temperature whereas permeate flux increased. Butanol flux increased slowly with the feed concentration while the water flux decreased. The overall result indicated that the separation factor decreased slowly with the feed concentration. The membrane, with a thickness of 55 μm, showed a total flux of 308.4 g/m²h with a separation factor of 26.8 at 70 °C, and butanol permeability reached 11.13×10⁵ Barrer with a membrane selectivity of 56.0.     

热浸渍晶种法制备高重复性NaA分子筛膜

利用热浸渍法和打磨法引入晶种合成NaA分子筛膜,将合成的NaA分子筛膜应用于乙醇/水混合体系,研究进料温度、进料侧压力及进料流量等对其分离性能的影响。结果表明,进料温度升高,渗透通量和分离因数呈增大趋势;进料侧压力增大,渗透通量增加,分离因数减小;进料流量增大,渗透通量明显增大,分离因数未发生明显变化。进料温度为75℃、进料侧压力为100kPa、相对真空度接近-0.1MPa、进料流量为16L/h时,所得NaA分子筛膜的渗透通量和分离因数分别为1.08kg.m-2.h-1和3 338,此时用于乙醇/水混合体系分离效果最佳。NaA分子筛膜的重复性高达80%。     

真空膜蒸馏法分离低浓度乙醇水溶液的试验研究

采用真空膜蒸馏的方法，对低浓度乙醇-水溶液的分离进行了试验研究，实验在中空纤维膜器中进行．实验表明：过程的操作参数对分离效率有较大的影响．在实验条件下，进口温度、料液流量、浓度和真空度的增加，膜通量将增加；分离因子随进口温度和真空度增加而减少，料液流量增加导致分离因子升高，浓度的变化对分离因子影响不大。     

丙酮／丁醇间歇萃取发酵

为了防止丙酮/丁醇发酵过程中代谢产物丁醇对丙酮/丁醇梭状芽孢杆菌(Closlridium acetobutylicum)的抑制作用,进行了萃取和发酵相结合过程的研究。从十三种有机化合物对丙酮/丁醇梭状芽孢杆菌的毒性以及它们的物理性能出发,选出了油醇和混合醇(油醇和硬脂醇的混合物)作为丙酮/丁醇萃取发酵的萃取剂。和用正交试验考察了以油醇作萃取剂时,发酵温度、初始葡萄糖浓度和油水比等三因素对游离细胞、固定化细胞的无搅拌间歇萃取发酵的影响。根据正交试验结果,研究了发酵温度41/35℃、油水比1∶2和不同初始葡萄糖浓度时的间歇搅拌萃取发酵。当初始葡萄糖浓度为110(g/1)时,发酵结束水相丁醇浓度5.12(g/1)、折合水相丁醇浓度16.27(g/1)、折合水相总溶剂浓度33.63(g/1),发酵过程的葡萄糖利用率98.0％。总浓剂产率0.312。研究结果表明:萃取发酵可以减轻产物丁醇对丙酮/丁醇梭状芽孢杆菌的抑制、提高初始葡萄糖浓度、减少生产过程的废水量,为降低产物分离的能耗和总溶剂的生产成本打下了基础。     

聚丙烯酸甲酯膜分离水-乙醇混合物的研究

本文介绍以丙烯酸甲酯、二乙烯三胺为基本原料合成的一种新型聚合物膜材料,并用渗透蒸发法通过该膜对水-乙醇混合物进行分离;研究了料液浓度、料液温度等评价条件对膜透过速率和分离系数的影响;计算了膜对不同浓度料液的表观透过活化能;测试了膜的溶胀度和溶胀膜的组成,利用测定结果讨论了溶液在膜中的溶解和扩散对透过速率和分离系数的影响。还利用红外分光光度计、电镜、动态粘弹测试仪等粗略探讨了膜的微观结构。     

硅氮烷疏水改性介孔分子筛填充PDMS制备杂化复合膜及渗透汽化性能

采用硅烷偶联剂对介孔分子筛疏水改性,并将其掺杂在聚二甲基硅氧烷(PDMS)中涂覆在聚砜基膜上制备有机无机杂化复合膜.对疏水改性介孔分子筛进行了BET测试及FT-IR等表征.BET测试结果显示,改性前后孔径分布发生明显变化;从FT-IR图中看出,改性后介孔分子筛的羟基峰明显减小甚至消失并且出现烷基等特征峰.通过扫描电镜(SEM)观察了有机无机杂化复合膜的形貌结构,并研究了分子筛添加量、料液浓度和操作温度等对杂化复合膜渗透汽化性能的影响.结果表明:采用1,1,3,3-四甲基二硅氮烷对介孔分子筛疏水改性最有效;疏水改性后介孔分子筛/PDMS杂化复合膜对醇/水溶液有较好的分离效果,当分子筛填充质量分数为20%、操作温度为40℃、进料液质量分数为3%时,杂化膜对乙醇/水体系的分离因子最高为9.8,渗透通量为1 002 g/(m2·h),对正丁醇/水体系的分离因子最高为65.4,渗透通量为1402 g/(m2·h).     

PU弹性网络对PAM凝胶吸水/脱水行为的影响

为改善聚丙烯酰胺凝胶(PAM)在吸水/脱水过程中对环境变化的响应性,制备了多孔聚氨酯弹性体(PU)与PAM的互穿网络结构(IPN),测试其在吸水/脱水过程中的质量和体积变化,并与PAM凝胶的响应行为进行比较,研究PU网络的回弹作用对PAM凝胶吸水/脱水行为的影响.分析表明,吸水过程中PU网络的作用主要表现为后期对溶胀网络的束缚;而在脱水过程中,其回弹行为对溶胀PAM凝胶的初期体积收缩具有明显的加速作用.这种PU/PAMIPN结构可以提高PAM作为传感/驱动器件的环境响应性.     

Study on concentrating sulfuric acid solution by vacuum membrane distillation

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操作条件对超滤姬松茸多糖的影响

利用标准化因子多元线性回归方法定量研究了操作压力、浓度和温度对超滤膜方法分离姬松茸多糖的膜通量及截留率的影响并建立了相应的数学关系式.研究结果表明:1)对通量而言,压力、浓度和温度均是显著性影响因素,其中压力和温度为正贡献、浓度为负贡献,影响程度依次为:浓度(78.3%)>压力(16.61%)>温度(5.09%);2)对截留率而言,压力和浓度是显著性影响因素,温度是影响因素但不是显著性影响因素,压力和温度为负贡献、浓度为正贡献,影响程度依次为:压力(47.35%)>浓度(42.7%)>温度(9.95%);3)得到了膜通量(J)及截留率(R)与压力(P)、质量浓度(p)和温度(T)之间的定量关系式.     

聚丙烯酸酯改性聚氨酯胶粘剂的研究

制备了聚酯型聚氨酯／聚丙烯酸酯互穿网络弹性体，将其溶解于溶剂中形成聚氨酯／聚丙烯酸酯粘合剂，考察了丙烯酸酯用量，异氰酸根与羟基摩尔比，催化剂和稳定剂用量，接枝及溶剂等对粘合剂粘合性能的影响，同时考察了粘合剂的储存性能。     

考虑热辐射作用的燃速相关性

本文以复合固体推进剂凝相燃烧模型为基础,发展了一种考虑热射辐对燃面作用的理论模型,得到了预示药条、缩比和全尺寸发动机燃速相关的半经验方法。对外加热辐射的四种复合推进剂和三种复合推进剂的药条、φ152mm与φ300mm发动机的燃速相关性进行了预示,结果与实验值相一致。该燃速相关方法可用于工程设计。     

Separation of xylo-oligosaccharides from enzymatic hydrolytes using membrane reactor

1　INTRODUCTIONMembranereactorsrepresentapromisingtech nologyforproductionandprocessinginthepharma ceuticalandfoodindustry .Theincreasingattentionto“natural like” productsandenviron mentalpro cessesmakesthemembranereactorsparticularlyat tractive,becausetheydonotrequirechemicaladdi tives ,areabletoworkundermildconditionsofpH ,temperature,and pressure ,andcanreducethefor mationofby products[1] .Thecatalyticactionofen zymesisextremelyefficientandselectivecomparedwithordinarychemicalcatalys…     

不同热处理介质对聚氨酯系中空纤维膜性能的影响

采用熔融纺丝制得聚氨酯系中空纤维膜,研究了不同热处理介质对膜性能的影响.结果表明:所制得的聚氨酯系中空纤维膜经热水介质处理后水通量随理论拉伸倍数的增加而增大,经热空气介质处理后水通量随理论拉伸倍数的增加先增大后减小;经热水介质处理后可提高聚氨酯系中空纤维膜断裂伸长率,而经热空气处理后则可提高其断裂强度;在相同压力条件下,热水介质处理后聚氨酯系中空纤维膜的水通量更易于稳定.     

Ag~+/离子液体支撑液膜蒸汽渗透分离苯/环己烷体系的研究

利用AgNO₃,AgBF₄和[bmim]BF₄,[bmim]PF₆离子液体制备Ag⁺/离子液体"填充型"支撑液膜,用于苯/环己烷的蒸汽渗透,研究了离子液体的种类、银盐阴离子种类、操作温度及原料液中苯含量等因素对苯/环己烷混合体系的蒸汽渗透膜分离性能的影响.结果显示:AgNO₃/[bmim][PF₆]支撑液膜对等体积配比的苯/环己烷混合体系分离效果较佳,35℃时渗透通量为14.81 g/（m²·h）,分离因子为36.59.     

基于PTFE中空纤维膜的膜蒸馏技术处理浓海水

通过调节挤出头的尺寸和拉伸倍数,制备出4种不同壁厚和孔径的聚四氟乙烯（PTFE）中空纤维膜。将PTFE中空纤维膜制成膜组件,采用真空膜蒸馏（VMD）技术处理浓海水。研究了PTFE中空纤维膜的壁厚和孔径、料液温度和流速、冷侧真空度等对产水通量和脱盐率的影响。结果表明：减小膜丝壁厚、增加膜孔径、提高料液温度、料液流速和冷侧真空度均可增加产水通量。但产水通量随浓缩倍数的增加而减小。整个实验过程中,4种PTFE中空纤维膜的脱盐率均保持在99.5%以上,且不受操作条件的影响。     

Influence of interpenetrating polymer networks (IPN) microstructure on underwater acoustic stealth performance

According to the configuration and absorption theory of polymer macromolecule materials, a kind of IPN with wider temperature range and higher damping property was designed and synthesized. By using the spectrum of dynamic mechanical thermal analysis (DMTA) and acoustic pulse tube device, the microstructure, phase separation degree, phase size and phase continuity of IPN with different components were analyzed. The experimental results show that the nano size grade of phase, the continuous and homogeneous IPN phase can provide higher absorption coefficient. The absorption coefficient of optimized sample I09 is 0.7 in 2 kHz, and the absorption peak is 0.9 in 4 kHz. Then the underwater acoustic properties of modified IPN filled with mica, micro-balloon and nano-SiO₂ were discussed respectively to indicate that the inhomogeneous property of filler-modified IPN can improve the underwater acoustic stealth performance effectively, and the micro size grade of these filler-modified IPN can work well in low frequency acoustic stealth.     

膜分离法回收不凝气中乙醇/水蒸气的实验研究

模拟传统发酵,将PTFE膜用于不凝气中乙醇/水蒸气的分离,研究了不凝气中乙醇浓度、进料温度、膜后真空度等操作条件对膜分离性能的影响,并对PTFE膜和ePTFE膜进行比较.结果表明,PTFE膜渗透通量随着气体中乙醇摩尔分数、进料温度、膜后真空度的增加而增加,温度与渗透通量符合Ar-rhenius方程.PTFE膜分离因子随气体中乙醇摩尔分数、进料温度的增加而增加,随膜后真空度的增加而减小.ePTFE膜相对于PTFE膜来说,具有较高的渗透通量,分离效果较好,有利于乙醇/水蒸气的分离.     

聚偏氟乙烯疏水平板膜用于真空膜蒸馏的研究

采用自制聚偏氟乙烯疏水平板膜,通过改变进水温度、进水流量、冷侧真空度及进料浓度等影响因素,对真空膜蒸馏的性能进行实验研究。结果表明,随进水温度（40-65℃）、进水流量（1.8-17.5 L/h）、冷侧真空度（0.038-0.093 MPa）的增加,膜通量呈增大趋势,最大可达39.22kg/（m^2·h）;随进料NaCl溶液浓度（1-40 g/L）的增加,膜通量减小,截留率增加。在40 g/L时,膜通量仅为9.59 kg/（m^2·h）,截留率达到98.6%。     

Influence of Interpenetrating Polymer Networks (IPN) Microstructure on Underwater Acoustic Stealth Performance

According to the configuration and absorption theory of polymer macromolecule materials, a kind of IPN with wider temperature range and higher damping property was designed and synthesized. By using the spectrum of dynamic mechanical thermal analysis (DMTA) and acoustic pulse tube device, the microstructure, phase separation degree, phase size and phase continuity of IPN with different components were analyzed. The experimental results show that the nano size grade of phase, the continuous and homogeneous I...