磺化聚苯醚质子交换膜的制备与性能研究

以氯磺酸为磺化剂制备了一系列不同磺化度的磺化聚苯醚(SPPO)膜,通过热重-红外联用分析、差示扫描量热分析、含水率测试、力学性能和电导率测试,探讨了SPPO膜作为质子交换膜用于燃料电池的可能性。结果表明,SPPO存在3个阶段的失重,分别归属于吸收的水分、磺酸基团及主链的降解,磺化之后热稳定性虽有所下降,但主链的降解温度基本保持不变,玻璃化转变温度明显升高;SPPO的含水率随着磺化度和温度的增加而增加;膜的拉伸强度则随着磺化度的增加而降低,且膜在湿态时的强度较干态时的要低,但与商业化的Nafion 112膜相比仍具有较高的强度;磺化度为40.1%的SPPO膜在室温下的电导率为1.16×10-2S/cm,与Nafion 112膜为同一数量级。     

聚丙烯腈/磺化聚苯醚质子交换膜的制备和性能

采用溶液共混浇铸法制备了一系列的聚丙烯腈/磺化聚苯醚(PAN/SPPO)共混质子交换膜.结果表明,磺酸基团成功引入交换膜,共混膜有较好的相容性,没产生相分离,PAN/SPPO共混膜的吸水率和溶胀率明显降低,其热性能稳定.与纯SPPO膜相比,虽然英质子传导率有所下降,但都在10-2～ 10-3S/cm数量级范围内,究全可...     

基团法估算磺化聚苯醚的溶解度参数

以氯磺酸为磺化剂制备了一系列不同磺化度的磺化聚苯醚（SPPO）。采用基团贡献法估算出了聚苯醚（PPO）及SPPO的溶解度参数值，随着磺化度的增加，溶解度参数逐渐增加，估算的结果与SPPO在不同溶剂中的溶解行为基本吻合。     

磺化SEBS的制备工艺研究

探究了影响SEBS磺化反应的各种因素。结果表明:较适宜的磺化试剂和溶剂分别为乙酰基磺酸酯和三氯甲烷;随着磺化反应时间的延长和磺化试剂用量的增加,产物磺化度均有不同程度的增大,达到一定程度后,磺化反应趋于平稳;低温反应的平衡磺化度高于高温反应的平衡磺化度,但平衡时间过长;磺化试剂配比n (乙酸酐)∶n (浓硫酸)=2∶1时,产物磺化度达到最大。当磺化试剂配比大于或小于2∶1时,磺化效率均有不同程度的降低。     

磺化壳聚糖的研制

研究和讨论了壳聚糖磺化反应中氯磺酸用量、反应温度、反应时间对产物中硫含量的影响,通过实验确定了最佳工艺条件。     

磺化聚砜的制备研究

聚砜（PSF）是目前工业上应用最广泛的超滤膜材料，它具有价廉易得，良好的机械强度、抗压密性、化学稳定性、耐热性，以及宽的pH使用范围（pH值为2～12）等优点；但它的憎水性也是人所皆知的，其危害主要表现在疏水溶质易在膜表面产生吸附和沉积，使膜孔受阻，造成膜污染，使膜的性能降低，使用寿命缩短。因此对聚砜的改性已受到广泛的重视．研究表明磺化可以明显改善聚砜膜的各项性能，本文研究了（CH3）3SiSO3Cl对聚砜的磺化过程，通过改变反应时间、温度、磺化剂的用量，确定最佳磺化条件为三氯甲烷，PSF配比15／1mg／L、（CH3）3SiSO3Cl／PSF配比1：1、反应24h、反应温度20℃。     

电镀领域的磺化反应

列举了在电镀领域中实际应用到的各类磺化产物，根据磺化产物在电镀中的作用的不同，对磺酸基团功能特性做了分类概括，以磺化剂的不同，分别列出反应通式和各种磺化产物；对各类磺化反应的优缺点进行了详细阐述和比较。     

磺化反应工艺研究进展

介绍目前磺化反应工艺的发展现状,对比了三氧化硫(SO3)、浓硫酸、发烟硫酸、氯磺酸、氨基磺酸等磺化剂的性能及其对磺化反应的影响,同时介绍了磺化反应的影响因素、磺化产物的分离测定方法和磺化反应工艺及设备。     

杀虫单磺化及其高纯粉剂制备工艺的研究

介绍了杀虫单的介质法磺化反应及结晶工艺的研究 ,探讨了影响磺化收率和杀虫单粉剂含量及出粉率的主要因素 ,找出了生产高纯度杀虫单粉剂的最优工艺条件。实验结果表明 :以含量为 50 %的氯化物盐酸盐为原料 ,按质量比为 1:0 .95比例加入浓度为 85%的甲醇介质进行磺化反庆 ,磺化收率可达 88%以上 ,生产的杀虫单含量≥ 95% ,折 10 0 %计的杀虫单出粉率≥ 4 6 % ,折 10 0 %杀虫单粉剂耗甲醇≤ 0 ,17t/t     

Compatibilization of Poly(2,6-dimethyl-l,4-phenylene oxide) and Poly(2,6-dichloro-l,4-phenylene oxide) with Sulfonated Polystyrene and its Na and Zn-neutralized Ionomers

Compatibility of acidic (H), Na, and Zn neutralized sulfonated polystyrene ionomer blends with Poly(2,6-dimethyl- 1,4-phenylene oxide) (PPO) and Poly(2,6-dichloro- 1,4-phenylene oxide) (PDCIPO) was investigated by Dilute Solution Viscometry (DSV) and Differential Scanning Calorimetry (DSC). The intrinsic viscosities of the blends, are measured in suitable solvents. The degree of compatibility of the blends is characterized by Δb parameter. According to the results, PPO is completely miscible, except for Na-neutralized 1.7 mol% sulfonated polystyrene (Na1.7SPS) which is completely immiscible with PPO and PDClPO. PDClPO is completely miscible with Zn-neutralized sulfonated polystyrene (Zn4.8SPS) and partially miscible with acid sulfonated polystyrene (4.8SPS). Received: 12 August 2001/Revised version: 21 January 2002/Accepted: 11 March 2003 Correspondence to Leyla Aras     

Synthesis, structures and thermal properties of new class epoxide-terminated telechelic poly(2,6-dimethyl-1,4-phenylene oxide)s

Dihydroxyl telechelic poly(2,6-dimethyl-1,4-phenylene oxide)s (1) with regiocontrolled end-group structures have been synthesized by oxidative polymerization of 2,6-dimethylphenol with various aromatic diols in the presence of CuBr/dibutylamine catalysts. The novel one- or two-armed telechelic derivatives based on aromatic diols as core and 1 as arms were subsequently epoxidized with epichlorohydrin and a series of new epoxidized poly(2,6-dimethyl-1,4-phenylene oxide)s (2) were accessible with number average molecular weight ranged from 3500 to 14,000. The end-group structures and regioselectivity of polymers were controlled by the CuBr/dibutylamine catalysts under different reaction conditions, and the structures and properties were studied by nuclear magnetic resonance spectroscopy, gel permeation chromatography, thermogravimetric analysis and differential scanning calorimetry. Upon heating in the presence of oxygen, the one-armed dihydroxyl telechelic polymer was converted via intermolecular coupling and redistribution reaction to the two-armed derivative with significant increase in its molecular weight and elimination of diol monomer. Treatment of dihydroxyl telechelic derivatives with epichlorohydrin and NaOH afforded the epoxide-terminated telechelic derivatives in 77-94% yields.     

A new long-side-chain sulfonated poly(2,6-dimethyl-1,4-phenylene oxide) (PPO)/polybenzimidazole (PBI) amphoteric membrane for vanadium redox flow battery

A new amphoteric membrane was prepared by blending long-side-chain sulfonated poly(2,6-dimethyl-1,4-phenylene oxide)(S-L-PPO) and polybenzimidazole(PBI) for vanadium redox flow battery(VRFB) application.An acid–base pair structure formed between the imidazole of PBI and sulfonic acid of S-L-PPO resulted in lowered swelling ratio. It favors to reduce the vanadium permeation. While, the increased sulfonic acid concentration ensured that proton conductivity was still at a high level. As a result, a better balance between the vanadium ion permeation(6.1 × 10-9 cm~2·s~(-1)) and proton conductivity(50.8 m S·cm~(-1)) in the S-L-PPO/PBI-10% membrane was achieved. The VRFB performance with S-L-PPO/PBI-10% membrane exhibited an EE of 82.7%, which was higher than those of pristine S-L-PPO(81.8%) and Nafion 212(78.0%) at 120 m A·cm~(-2). In addition, the S-LPPO/PBI-10% membrane had a much longer self-discharge duration time(142 h) than that of Nafion 212(23 h).     

Copolymers of poly(2,6-dimethyl-1,4-phenylene ether) and ester units

Copolymers of telechelic poly(2,6-dimethyl-1,4-phenylene ether) segments with terephthalic methyl ester endgroups (PPE-2T, 3700 g/mol) and different diols were made via a polycondensation reaction. The terephthalic endgroups of PPE-2T are stable during this reaction. The T_g of these polyether-ester copolymers decreases with increasing diol length and diol flexibility. The T_g can be set between 100 and 200 °C by changing the type of diol. However at increasing diol length the T_g becomes broader and the test bars are less transparent because the extent of phase separation increases with increasing diol length. Only polymers with a diol length up to C12 are homogeneous. Phase separation is probably enhanced by the bimodal molecular weight distribution of PPE-2T. Phase separation can be suppressed by using shorter PPE-2T segments with a short diol. It is even better to use fractionated, monomodal PPE-2T. Copolymerisation is much more effective in decreasing the T_g of PPE and therefore its processability than blending with polystyrene. It is expected that the processability of these copolymers is much better than that of PPE.     

Poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) multi-bonded carbon nanotube (CNT): Preparation and formation of PPO/CNT nanocomposites

Poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) multi-bonded carbon nanotube (CNT) (CNT-PPO) was prepared using brominated PPO under the condition of atom transfer radical polymerization. The structure and properties of CNT-PPO were characterized with FTIR, Raman spectroscopy and thermal analyzer. The PPO layer in a thickness of about 4.5 nm was observed covering on the side wall of CNT with a high-resolution TEM. The PPO modification warrants the good dispersion of CNTs in PPO in the formation of PPO/CNT nanocomposites, which demonstrated enhanced mechanical properties and increases in electrical conductivity. The developed approach of CNT modification with engineering plastics can be applied to other polymers and preparation of functional polymer/CNT nanocomposites.     

Synthesis and characterisation of telechelic poly(2,6-dimethyl-1,4-phenylene ether) for copolymerisation

Telechelic poly(2,6-dimethyl-1,4-phenylene ether) (PPE) segments are interesting starting materials, for example for copolymerisation. A good method to make partly bifunctional PPE-2OH is by redistribution or depolymerisation of high molecular weight commercial PPE with tetramethyl bisphenol A. The product has a bimodal molecular weight distribution because only ∼70-80% of high molecular weight starting material is depolymerised. The phenolic endgroups can be modified easily by a fast and complete reaction with methyl chlorocarbonyl benzoate. The product after endgroup modification is called PPE-2T and has two terephthalic methyl ester endgroups and a molecular weight of 2000-4000 g/mol. The functionality of these PPE-2T products is around 1.8. The bimodal PPE-2OH and PPE-2T products can be separated in a high and low molecular weight fraction by selective precipitation. The low molecular weight fraction has a narrow molecular weight distribution with a polydispersity between 1.2 and 1.5.     

Synthesis of poly(2,6-dimethyl-1,4-phenylene oxide) derivatives in water using water-soluble copper complex catalyst with natural ligands

Poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) was synthesized by oxidative polymerization of 2,6-dimethylphenol (DMP) using a water-soluble copper complex catalyst under oxygen and with natural ligands in alkaline water. Arginine, guanine, adenine, cytosine, histidine, and folic acid were used as ligands for the copper complex. Arginine performed the best, with a yield of 72%, a number-average molecular weight (M_n) of 4400, and a molecular weight distribution (M_w/M_n) of 1.7. It was then used to optimize reaction conditions. Surfactants, temperature, and sodium hydroxide concentration were varied in copolymerization of DMP and 2-allyl-6-methylphenol (AMP) to produce allyl-containing PPO with 77% yield (M_n = 4500; M_w/M_n = 1.8). The optimum conditions were applied to copolymerization of DMP, AMP, and bisphenol A, leading to dihydroxyl PPO analogs containing thermally cross-linkable allyl groups. The thermal properties of these thermosetting PPOs were studied by differential scanning calorimetry, thermogravimetric analysis, and Fourier-transform infrared spectroscopy.     

Blends of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) with polystyrene-based thermoplastic rubbers: A comparative study

This work presents the first part of our study on the modification of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) with styrenic thermoplastic rubbers. Polystyrene-b-polyisobutylene-b-polystyrene (SIBS), polystyrene-b-polybutadiene-b-polystyrene (SBS) and polystyrene-b-poly(ethylene/butylene)-b-polystyrene (SEBS) triblock copolymers were melt blended with PPO and the blends were characterized. Differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA) and transmission electron microscopic (TEM) studies revealed that PPO/SEBS blends displayed the most pronounced phase-separated morphology with largest rubbery domains. SBS showed the most miscibility, and the least detrimental effect on dynamic mechanical properties and tensile strength. The results of this comparative study guided us to develop optimum conditions for the impact modification of PPO by SIBS thermoplastic rubbers.     

Kinetics of photo-oxidative degradation and stabilization of poly(2,6-dimethyl-1,4-phenylene oxide) by metal dialkyl dithio phosphate

The kinetics of photo-oxidative degradation and stabilization of poly(2,6-dimethyl-1,4-phenylene oxide) have been studied in the temperature range 313-363 K using monochromatic light of 365 nm with a constant intensity flux of 8.7 × 10^?9 einstein s^?1 cm^?2 in the absence and presence of Ni(II) O,O′-diisopropyldithiophosphate. The course of degradation and stabilization was determined by means of light scattering and spectroscopic techniques. The extent of photodegradation was followed by carbonyl formation, gel content and activation energy. The incorporation of 1.2 wt% stabilizer in the matrix of the polymer films exercises the maximum protective influence on the photodegradation of the polymer.     

Dielectric,mechanical and thermal properties of some chlorinated poly (p-phenylene oxide)s in the solid state

The dielectric, mechanical and thermal properties were investigated for poly(2,6-dichloro-1,4-phenylene oxide) (PDCPO), poly(2-chloro-6-methyl-1,4-phenylene oxide) (PCMPO) and poly(2,6-dimethyl-1,4-phenylene oxide) (PDMPO). PDCPO exhibited two dielectric secondary relaxations designated as β and γ processes around 160 and 100K, respectively. The γ process was assigned to the motion of a trace of chloroform included in the PDCPO film. A blend film PDMPO/PCMPO ($\text{9}\text{1}$ mixing ratio) exhibited dielectric relaxation around 330K and the process was assigned to the rotation of phenyl group with respect to oxygen-phenyl-oxygen axis. No dielectric relaxation was observed for the PDMPO film dried carefully, while the PDMPO film kept under an atmosphere of water vapour exhibited dielectric relaxation due to the motion of the water molecules at about 180K. Tensile stress at break measured on PDCPO prepared by Stamatoff's method was 38 MPa and was much higher than that for PDCPO prepared by the method reported by Blanchard et al. Temperature dependence of the dynamic Young's modulus for PDCPO measured at 110 Hz exhibited no appreciable loss peak in the range below 480K. Glass transition temperatures for PDCPO, PCMPO and PDMPO were determined to be 490, 445 and 500K, respectively, by differential scanning calorimetry.