磺化聚醚砜/聚醚砜共混膜的制备及膜催化酯化反应动力学研究

以聚醚砜(PES)为基体,磺化聚醚砜(SPES)为催化活性成分,通过溶剂挥发法制备SPES/PES共混膜,用于酸化油(酸值153 mg KOH/g)酯化反应制备生物柴油,并研究了SPES/PES共混型催化膜酯化反应动力学。结果表明,在不同反应温度(45,55,65,75℃),不同的催化剂用量(0.68%,1.35%和2.70%)以及醇油质量比(1∶1,2∶1,5∶1,8∶1和10∶1)条件下,通过反应动力学计算出相应的反应速率以及反应级数。随着催化剂用量和醇油质量比的增加,反应速率逐渐增加,反应级数也增大,平均反应级数为n=2.2,而指前因子和活化能逐渐减小,说明由反应控制逐渐转为混合控制和反应控制。建立了SPES/PES共混型催化膜酯化反应动力学模型。得到实验值与理论值吻合程度较高(误差在±5%左右),验证了动力学模型的正确性。     

磺化聚醚砜/聚醚砜共混膜催化酯化反应性能研究

制备了磺化聚醚砜SPES膜和3种磺化度的SPES/PES共混膜用于催化酯化酸化油制备生物柴油。考察了磺化度、催化膜用量、酸化油和甲醇质量比、反应时间对酯化反应的影响。结果表明,单独使用SPES催化膜较脆,而SPES/PES共混膜机械强度较好,其中磺化度20.3%SPES/PES膜的重复使用性能最好。SPES/PES共混膜催化酯化酸化油制备生物柴油的最佳反应条件为:磺化度20.3%的SPES/PES共混膜为催化剂,催化膜用量1.66%,醇油质量比为1∶1,反应温度65℃,反应时间6 h,此时酸化油转化率为97.44%。     

磺化聚醚砜/聚醚砜共混膜催化酯化反应性能研究

制备了磺化聚醚砜SPES膜和3种磺化度的SPES/PES共混膜用于催化酯化酸化油制备生物柴油。考察了磺化度、催化膜用量、酸化油和甲醇质量比、反应时间对酯化反应的影响。结果表明,单独使用SPES催化膜较脆,而SPES/PES共混膜机械强度较好,其中磺化度20.3%SPES/PES膜的重复使用性能最好。SPES/PES共混膜催化酯化酸化油制备生物柴油的最佳反应条件为:磺化度20.3%的SPES/PES共混膜为催化剂,催化膜用量1.66%,醇油质量比为1∶1,反应温度65℃,反应时间6 h,此时酸化油转化率为97.44%。     

新型聚醚砜-磺化聚醚砜共混膜的性能研究

以浓硫酸为聚醚砜(PES)的溶剂和磺化剂,制备磺化聚醚砜(SPES)。选取磺化度(DS)为14%的SPES溶液,制备PES-SPES共混膜,考察了共混膜的脱盐效果和抗污染性能。结果表明,共混膜的基质材料中,随SPES、PES的质量比的增加,共混膜表面膜孔径增大,断面结构由指状孔向海绵状孔转化,共混膜水通量增加,截留率降低,当SPES的DS为14%、SPES、PES的质量比0.75时,制得共混膜水通量为253.7 L/(m~2·h),对PEG6000、PEG10000和PEG20000的截留率分别为56.8%、74.5%和90.6%;共混膜在相同测试条件下对Na_2SO_4截留效果大于NaCl,经亲水改性的PES-SPES共混膜亲水性提高,抗污染性能明显增强。     

磷钨酸/磺化聚醚砜/聚酯非织造布复合膜制备、表征及催化酯化性能

针对催化酯化反应中,传统的强酸、强碱催化剂会导致设备腐蚀严重,产生大量的废酸和废碱,造成环境污染等问题,采用溶液相转化法以聚酯非织造布(NWF)为支撑材料,磷钨酸(HPW)/磺化聚醚砜(SPES)为铸膜液,制备HPW/SPES/NWF复合催化膜。并对复合催化膜结构采用场发射扫描电镜(FESEM)、压汞仪和透射电镜(TEM)进行表征。研究了复合膜结构与性能之间的关系,考察了HPW加入量、进料流速、醇油质量比对酯化性能的影响以及复合膜重复使用性。结果表明,FESEM观察复合膜为均一的海绵状结构。压汞仪得到复合膜的平均孔径在60μm左右,孔隙率为65%。TEM得到HPW均匀地分散在SPES中。在最佳实验条件下,HPW/SPES/NWF复合催化膜转化率达到96.32%,重复使用5次转化率仍保持在96.03%。     

聚乙烯吡啶钯接枝聚醚砜膜催化还原对硝基苯酚

以聚醚砜(PES)为原料、氯甲基乙醚为氯甲基化试剂,制备了氯甲基化聚醚砜膜,该膜经碱处理后,采用乙烯基三甲氧基硅烷进行改性,得到聚4-乙烯吡啶接枝聚醚砜膜。再将该接枝膜与氯化钯反应,制成聚乙烯吡啶钯接枝膜。将该膜应用于对硝基苯酚的催化还原反应,考察了催化膜用量、反应温度对对硝基苯酚还原反应的影响,并研究了催化膜的重复使用性能。结果表明:增加催化膜用量以及提高反应温度均能使对硝基苯酚的还原反应速率加快。     

聚醚砜/磺化聚醚醚酮共混膜的制备和性能

采用流延法制备了聚醚砜(PES)含量不同的PES/磺化聚醚醚酮(SPEEK)共混膜。PES与SPEEK具有良好的相容性。所制备PES/SPEEK共混膜的含水率、溶胀度和甲醇透过系数均随PES含量的增加而降低。虽然共混膜的质子传导性能有所降低.但阻醇性能和溶胀性能提高,这说明PES/SPEEK共混膜是一种很好的直接甲醇燃料电池用固体高分子电解质膜材料。     

聚醚砜的磺化与热性能

以浓硫酸为溶剂 ,氯磺酸为磺化剂对聚醚砜 (PES)进行了磺化 ,制备了不同磺化度的磺化聚醚砜 (SPES)。探讨了反应的影响因素 ,分析了 SPES的热稳定性。结果表明 SPES的 Tg较 PES升高 ,随着磺化度的增加 ,SPES的降解温度降低。     

聚醚砜质量分数对聚偏氟乙烯/聚醚砜共混膜性能和结构的影响

用与聚醚砜共混的方法来改善聚偏氟乙烯膜的抗收缩性能,以二甲基乙酰胺作溶剂,聚乙烯吡咯烷酮为添加剂,研究了聚醚砜(PES)质量分数对聚偏氟乙烯/聚醚砜共混膜的收缩率、水通量、截留率及形态结构的影响。聚醚砜的加入可以有效地降低共混膜的收缩率,在w(PES)=1.5%时,共混膜的水通量取得极大值,截留率取得极小值。     

磺化聚醚砜(SPES)/聚醚砜(PES)合金超滤膜的研究

本文研究了磺化聚醚砜 (SPES) /聚醚砜 (PES)合金组份变化对膜性能的影响 ,通过选择适当的合金比例研制得到超滤膜 ,在 0 .2Mpa操作压力下 ,对聚乙二醇分子量为 1万的截留率大于 90 % ,水通量为 80L/m2 ·h ,对阴离子脱盐率PO3 -4 >SO2 -4 >CL-。通过扫描电镜观察膜的断面结构 ,结果表明 :PES膜断面形态属于典型的非对称指状孔结构 ,SPES/PES膜断面形态是致密的海绵状结构 ,致密层部分比SPES薄 ,SPES膜断面形态是较厚的海绵状结构 ,致密层部分多     

Synthesis and characterization of polyethersulfone membranes

Phase inversion method was used to prepare polyethersulfone (PES) ultrafiltration (UF) membranes. Polyethylene glycol (PEG); N, N-dimethyl formamide (DMF) and water were utilized as pore-forming additive, solvent and non-solvent, respectively. Effects of PES and PEG concentrations in the casting solution, PEG molecular weight (MW) and coagulation bath temperature (CBT) on morphology of the prepared membranes were investigated. Taguchi experimental design was applied to run a minimum number of experiments. 18 membranes were synthesized and their permeation and rejection properties to pure water and human serum albumin (HSA) solution were studied. It was found out that increasing PEG concentration, PEG MW and CBT, accelerates diffusional exchange rate of solvent (DMF) and non-solvent (water) and consequently facilitates formation of macrovoids in the membrane structure. The results showed that, increasing PES concentration, however, slows down the demixing process. This prevents instantaneous growth of nucleuses in the membrane structure. Hence, a large number of small nucleuses are created and distributed throughout the polymer film and denser membranes are synthesized. A trade-off between water permeation and HSA rejection was involved, with membranes having higher water permeation exhibited lower HSA rejection, and vice versa. Hence, optimizing preparation variables to achieve high pure water permeation flux along with reasonable HSA rejection was inevitable. Analysis of variance (ANOVA) showed that all parameters have significant effects on the response (water flux and HSA rejection). However, CBT and PES concentration were more influential factors than PEG concentration and MW on the responses.     

酚酞基聚醚砜溶液的流变性研究

采用锥板式流变仪研究了酚酞基聚醚砜/二甲基乙酰胺(PES-C/DMAc)的流变性能。结果表明:溶液的质量分数为18%～28%时,PES-C/DMAc溶液属于切力变稀流体,随着PES-C浓度的增加,非牛顿指数降低,零切粘度上升;溶液温度为20～100℃时,随着溶液温度的升高,PES-C/DMAc溶液非牛顿指数上升,零切粘度降低。温度升高,有利于提高溶液的可纺性。根据Arrhenius方程,溶液质量分数为18%～28%,PES-C/DMAc溶液的粘流活化能随浓度的增加而缓慢增加,但变化不大。     

Hydrophobic polyethersulfone porous membranes for membrane distillation

Membrane distillation (MD) is a thermal, vapor-driven transportation process through micro porous hydrophobic membranes that is increasingly being applied to seawater and brine desalination processes. Two types of hydrophobic microporous polyethersulfone flat sheet membranes, namely, annealed polyethersulfone and a polyethersulfone/tetraethoxysilane (PES/TEOS) blend were prepared by a phase inversion process. The membranes were characterized and their performances were investigated using the vacuum membrane distillation of an aqueous NaCl solution. The performances of the prepared membranes were also compared with two commercially available hydrophobic membranes, polytetrafluorethylene and polyvinylidene fluoride. The influence of operational parameters such as feed temperature (25–65 °C), permeate vacuum pressure (200–800 mbar), feed flow rate (8–22 mL/s) and feed salt concentration (3000 to 35000 mg/L) on the MD permeation flux were investigated for the four membranes. The hydrophobic PES/TEOS membrane had the highest salt rejection (99.7%) and permeate flux (86 kg/m²·h) at 65 °C, with a feed of 7000 ppm and a pressure of 200 mbar.     

POSS-induced rheological and dielectric modification of polyethersulfone

Polyhedral oligomeric silsesquioxane (POSS) nanostructured chemicals, when incorporated at low levels in thermoplastics, provide processability enhancement and viscosity reduction without compromising other bulk physical properties. POSS has been relatively unexplored in high performance polymers, and there is incomplete understanding of the mechanisms by which POSS produces flow improvements. In this study, polyethersulfone (PES) was melt-blended with trisilanolphenyl (TSP)-POSS and dodecaphenyl (DP)-POSS; and rheological, dielectric spectroscopy, and scanning electron microscopy evaluations were conducted to identify structure/property/processing relationships. TSP-POSS yielded greater processability improvements and viscosity reductions than DP-POSS, suppressed low temperature relaxations to a larger extent, and displayed a greater degree of nanoscale dispersion in the polymer matrix. The findings are evaluated in terms of competing theories of POSS viscosity reduction.     

熔融法纺制聚醚砜纤维的探索研究

采用国产聚醚砜(PES)树脂为原料,添加不同的增塑剂,在不同的实验条件下进行熔融法纺丝实验,并对其热性能、流变性、可纺性及纤维的力学性能进行了研究。通过对聚醚砜树脂的分子质量和增塑剂种类及含量进行调整,在适当的工艺条件下,该聚合物流动性有了明显改善,具有良好的熔融可纺性。其中以按100／20配比在PES-E中添加3#增塑剂的纺丝效果最好。     

Permeation properties of CO2and CH4in asymmetric polyethersulfone/polyesterurethane and polyethersulfone/polyetherurethane blend membranes

The transport performances of carbon dioxide and methane were studied in polyethersulfone,polyethersulfone/polyeterurethane (PES-ETPU) and polyethersulfone/polyestherurethane (PES-ESPU) blend membranes separately with different compositions.The variations in the structural characteristics of PES membrane after incorporation of ESPU and ETPU were investigated by different techniques.Additionally,the effect of pressure and composition on the permeance of CO2,CH4and ideal selectivity of CO2/CH4were checked on the membranes. The results revealed that the morphology of the blend membranes was affected by two opposite factors:thermo-dynamic enhancement and kinetic hindrance.The membranes with denser sponge layers were formed at lower ratio of PU/PES,while more porous structure with enlarged macrovoids membranes were observed at higher PU content.The results indicated that adding PU to PES membrane,caused permeance improvement of the gases with nearly no change and/or reduction in ideal selectivity of CO2/CH4.Moreover,PES-ETPU membranes showed higher permeability and less CO2/CH4selectivity in comparison with PES-ESPU samples. For PES-ESPU membrane containing 1.5% ESPU,CO2permeance at 10 bar was improved up to 20% with almost no change in CO2/CH4selectivity with respect to PES.Finally,response surface methodology was used to evaluate the effects of the operating parameters on the permeance and ideal selectivity.