基于聚醚砜(PES)超滤膜的粘杆菌素发酵液预处理过程优化

利用超滤对粘杆菌素发酵液进行膜分离处理并对其工艺过程进行优化。根据膜材料特性,选择聚醚砜(PES)为基材的超滤膜,通过不同截留分子量超滤膜的分离性能比较、操作条件选择,最终确定PES-10(截留分子质量为10 000 u)为超滤膜件,适宜的操作压力为0.3 MPa、料液pH值为6。经过超滤处理,滤液蛋白质含量为4.6mg/100mL,蛋白质去除率为96%,吸光度为0.185,发酵液中的色素得到有效地去除。     

Electrosynthesis of dimethylsulfone from dimethylsulfoxide at a dimensionally stable anode

Galvanostatic electrochemical oxidation of dimethylsulphoxide (DMSO) to dimethylsulfone (DMSO₂) has been effected at a dimensionally stable anode (DSA) under different conditions of current density and reaction media, in both a batch and a flow reactor (membrane cell with an ion-exchange membrane between the two working electrodes) functioning in batch recirculation mode. Excellent yields of the sulfone have been obtained under both conditions. The product has been characterized by various physicochemical techniques. The operational conditions giving maximum yield of the product have been established. The electrochemical oxidation of DMSO has also been studied by cyclic voltammetry at a glassy carbon (GC) electrode. The mechanism of electrochemical oxidation and the advantages of the present methods over existing ones, are discussed.     

青霉素钾,青霉素亚砜和青霉素砜的薄层色谱法分离和鉴别

用薄层色谱法分离和鉴别青霉素钾、青霉素亚砜、青霉素砜，斑点清晰，重现性好，可作为中间体的检测。     

Electrochemical synthesis and spectroelectrochemical behavior of poly(diphenylamine-co-4,4′-diaminodiphenyl sulfone)

The electroactive copolymer of diphenylamine (DPA) and 4,4′-diaminodiphenyl sulfone (DADPS) was synthesized electrochemically in 4 M H₂SO₄ and ethanol medium. Both electrochemical synthesis and characterization of the copolymer deposited on a glassy carbon electrode (GCE) were carried out using cyclic voltammetry. The voltammograms exhibited different patterns of behavior with different feed concentrations of DPA. Equimolar concentrations of DPA and DADPS demonstrated very efficient growth of the copolymer film on the surface of the GCE. The copolymer exhibited high solubility in dimethyl sulfoxide (DMSO). The scan rate exerted little-effect on this GCE copolymer film, revealing the film's excellent electroactive adherent properties. The effect of pH on the copolymer film showed that the polymer was electrochemically active up to pH 7.0. Spectroelectrochemical analysis of the copolymer film, carried out on an indium tin oxide (ITO) plate, showed multicolor electrochromic behavior when the applied potential was changed. The copolymer was characterized by FTIR and ¹H NMR spectral data. The surface morphology was studied using SEM analysis, the grain size of the copolymer was measured using XRD studies and was found to be 56 nm. The electrical conductivity of the copolymer was 2.65 × 10⁻² S cm⁻¹, as determined using a four-probe conductivity meter.     

Monomer sequence determinations of aryl ether sulphone copolymers as determined by 13C n.m.r.

The monomer sequence distributions of three types of aryl ether sulphone copolymers have been determined by ¹³C n.m.r. spectroscopy. Two amorphous aryl ether sulphone copolymers were shown to have transetherified (or ether interchanged) during polymerisation to become random copolymers. The residues in these copolymers were (i)—OøOøSO₂øS—and (ii)—OøSO₂øøSO₂ø—-where ø denotes 1,4-phenylene. Copolymers of 50:50 aryl ether sulphone and aryl ether ketone made from different combinations of monomers were found to have different solubilities in dimethyl sulphoxide, and from ¹³C n.m.r. data this was shown to correlate with the amount of transetherification which had taken place during the polymerisations. The ¹³C n.m.r. chemical shifts for some of the carbon nuclei in these polymers were sensititive to functional groups situated even as far away as three or four aromatic nuclei along the polymer chain.     

耐高温新型含杂萘联苯聚醚砜嵌段共聚物的性能

将氯端基聚醚醚砜齐聚物和杂萘联苯类双酚羟端基齐聚物通过溶液缩聚,成功地合成了一系列新型聚醚醚砜-聚醚砜(PEES-PPES)嵌段共聚物,并用IR、DSC、TGA、X-WAXD等测试手段对聚合物进行了表征。结果表明:PEES-PPES具有较高的热稳定性,较好的溶剂溶解性;砜基比例的变化对PEES-PPES的热性能有较大的影响,表明砜基对杂萘联苯聚醚砜改性效果明显。     

Preparation and properties of crosslinked sulphonated poly(arylene ether sulphone) blend s for direct methanol fuel cell applications

HMS-based sulphonated poly(arylene ether sulphone) (HMSSH) is synthesised using 4,4′-dihydroxy-α-methylstilbene (HMS) monomer to introduce an interesting stilbene core as crosslinkable group. Crosslinked blend membranes are obtained by blending the BPA-based sulphonated poly(arylene ether sulphone) (BPASH) with crosslinkable HMS-based sulphonated poly(arylene ether sulphone) by UV irradiation of the blend membrane. Compared to the native BPASH with crosslinked BPASH/HMSSH blend membranes, the crosslinked blend membranes greatly reduce the water uptake and methanol permeability with only a slight reduction in proton conductivity. The crosslinked blend membrane, which has a 6% HMSSH content, has a water uptake of 59%, methanol permeability of 0.75 × 10⁻⁶ cm² s⁻¹, and proton conductivity of 0.08 S cm⁻¹. A membrane-electrode assembly is used to investigate single-cell performance and durability test for DMFC applications. Both the power density and open circuit voltage are higher than those of Nafion^® 117. A maximum power density of 32 mW cm⁻² at 0.2 V is obtained at 80 °C, which is higher than that of Nafion^® 117 (25 mW cm⁻²).     

聚氯乙烯/聚醚砜共混小孔超滤膜的研制

聚氯乙烯与聚醚砜属部分相容体系。采用溶胶-凝胶相转化法,改变聚合物共混比例、混合溶剂、添加剂用量,制备了一系列聚氯乙烯/聚醚砜(PVC/PES)共混超滤膜。通过调配铸膜液中聚合物共混比例,可大大提高共混膜的强度和韧性。其水通量和截留率与同类日本产高分子分离膜相比,均有较大提高。     

Deposition of aromatic polyimide thin films in supercritical carbon dioxide

The deposition of aromatic polyimide (API) thin films was carried out in supercritical carbon dioxide (scCO₂) with 20 mol% of N,N-dimethylformamide (DMF) as a cosolvent, and using 4,4′-diaminodiphenyl ether (ODA) and pyromellitic dianhydride (PMDA) as monomers. A new apparatus based on a flow method that consisted of a cold-wall type reactor and two supply lines for each of the API monomers was used. The effect on the morphology of the films was investigated at feeding monomer concentrations and deposition temperatures ranging from 5 × 10⁻⁴ to 5 × 10⁻⁶ on a mole fraction basis and from 423 to 523 K, respectively. The results showed that increasing the monomer concentration and decreasing the deposition temperature increased the thickness of the films, and a smooth surface of the film was obtained at 423 K. Additionally, FT-IR study and thermogravimetric (TG) analysis of the film deposited at monomer mole fractions of 5 × 10⁻⁵ and at a deposition temperature of 473 K were also carried out. The FT-IR spectrum of the deposited film in scCO₂ with DMF represented imide structures although there was a small peak of amide carbonyl stretching that originated from the polyamic acid and DMF. The TG curve indicated the temperature of 5% weight loss was more than 800 K under an air atmosphere after complete imidization.     

Toughening of aromatic diamine-cured epoxy resins by modification with hybrid modifiers composed of N-phenylmaleimide–styrene copolymers and N-phenylmaleimide–styrene–p-hydroxystyrene terpolymers

Hybrid modifiers composed of N-phenylmaleimide–styrene copolymers (PMS), and N-phenylmaleimide–styrene–p-hydroxystyrene terpolymers (PMSH) containing pendent p-hydroxyphenyl groups as functionalities, were used to improve the toughness of bisphenol-A diglycidyl ether epoxy resin cured with p,p′-diaminodiphenyl sulphone. The hybrid modifiers were effective in toughening the epoxy resin. When using the modifier composed of 10 wt% PMS (M?_w 313000) and 2.5 wt% PMSH (2.5 mol% p-hydroxystyrene units, M?_w 316000), the fracture toughness (K_IC) for the modified resins increased 100% with no deterioration in the flexural properties and the glass transition temperature. The improvement in toughness of the epoxy resins was attained because of the co-continuous phase structure and the improvement in interfacial adhesion. The toughening mechanism is discussed in terms of the morphological characteristics of the modified epoxy resin systems.