马来酸酐固相接枝微晶纤维素

研究了马来酸酐(MAH)固相接枝微晶纤维素(MCC)的反应工艺,并通过红外光谱、X射线衍射对微晶纤维素及其接枝产物进行了对比表征。红外结果表明,接枝产物在1719.13cm-1处出现了酯基的伸缩振动吸收峰,可定性地说明马来酸酐与微晶纤维素发生了接枝反应。X射线衍射结果表明,接枝反应并没有改变微晶纤维素的结晶结构,仅使其结晶度下降。文中探讨了接枝反应温度、时间和MAH用量等因素对接枝取代度的影响。当马来酸酐与微晶纤维素质量比为8%,反应温度90℃,反应时间3h,可得到取代度达0.1的马来酸酐接枝微晶纤维素。     

氯化聚丙烯接枝改性胶粘剂的合成及粘接性能研究

以甲苯为溶剂,过氧化二苯甲酰(BPO)为引发剂,采用甲基丙烯酸羟乙酯(HEMA)通过自由基聚合接枝对氯化聚丙烯(CPP)进行了改性。研究了反应温度、反应时间、引发剂用量、单体用量对氯化聚丙烯改性胶粘剂粘接性能的影响,并对接枝产物进行了FTIR表征,确定出较理想的工艺条件为反应温度θ=110℃,反应时间t=4h,m(CPP):m(HEMA):m(BPO)=1:1:0.1。     

褐煤腐植酸磺化工艺研究

以褐煤腐植酸、Na2SO3、NaOH为原料对褐煤腐植酸进行磺化改性;采用电导法对其磺化度进行测定;通过考察固液比、反应时间、反应温度对磺化腐植酸磺化度的影响获得最佳工艺参数：磺化剂与腐植酸钠溶液的液固比2：20、磺化温度50℃、磺化时间90min;产品磺化度为17．7％;红外光谱表明,磺化腐植酸中磺酸基团明显增多,确实发生了磺化反应。     

原硅酸钠改性的聚偏氟乙烯接枝苯乙烯磺化膜接枝率的影响因素

以过氧化苯甲酰(BPO)作引发剂,通过溶液接枝聚合法把苯乙烯接枝到原硅酸钠改性的聚偏氟乙烯(PVDF)膜上,磺化后得到聚偏氟乙烯接枝苯乙烯磺酸(PVDF-g-PSSA)电解质膜。讨论了原硅酸钠的用量、接枝反应时间、反应温度、BPO浓度、苯乙烯单体浓度等对PVDF-g-PSSA膜接枝率的影响。结果表明,原硅酸钠用量为10%(质量分数,下同)、BPO浓度为0.016mol/L反应液、苯乙烯与四氢呋喃的比例为4∶1、在75℃水浴中,氮气保护下反应10h,可得到接枝率为16.1%、电导率为1.6×10-2S/cm的PVDF-g-PSSA电解质膜。     

改性聚丙烯/聚苯胺复合材料的制备及抗静电性能

采用溶液接枝法,以浓硫酸为磺化剂制备了磺酸改性聚丙烯接枝苯乙烯(MPP),并采用原位聚合法制备了改性聚丙烯/聚苯胺(MPP/PANI)高分子复合材料。考察了单体用量、引发剂用量、溶剂用量、反应时间等因素对接枝率的影响,以及磺化反应的液固比、磺化时间、反应温度等因素对产物磺化度的影响,确定了最佳制备工艺条件。通过红外光谱、DSC、数字高阻计、扫描电镜等手段对产物进行了分析表征。实验结果表明,MPP/PANI高分子复合材料有良好抗静电性;由扫描电镜照片和力学性能测试可知,所制备的抗静电复合物与PP有良好相容性。     

一种BOPP膜胶粘剂的研究

以甲苯为溶剂,过氧化二苯甲酰(BPO)为引发剂,通过自由基聚合,采用丙烯腈(AN)接枝改性氯化聚丙烯(CPP),得到一种BOPP膜胶粘剂.研究了反应温度、反应时间、AN和BPO的质量对CPP胶粘剂改性的粘附性能的影响;得出较佳的工艺条件为:反应温度T=100℃,反应时间t=2.0 h,反应物料的质量比m(CPP):m(AN):m(BPO)=100:2.0:0.20时,改性的CPP胶粘剂有较高的粘接强度.     

聚醚酰亚胺的磺化与热性能

以氯磺酸为磺化剂成功制备了一系列不同磺化度的磺化聚醚酰亚胺(SPEI),并对SPEI的结构和热性能进行了研究。采用热重-红外联用技术对SPEI的热失重及失重产物分析表明SPEI有三个阶段的失重,分别归属于吸收的水分、磺酸基团及主链的降解,磺化之后热稳定性有所下降,磺酸基团在230℃~370℃区间发生降解,但主链的降解温度基本保持不变;SPEI的玻璃化转变温度(Tg)明显升高,当磺化度为62.6%时,体系出现了两个独立的Tg。     

PP包装膜胶粘剂的研究

以过氧化二苯甲酰(BPO)为引发剂,通过自由基聚合,采用马来酸酐(MAH)接枝改性氯化聚丙烯(CPP);研究了不同反应温度、不同反应时间和不同质量的MAH和BPO对改性PP包装膜的粘附性能的影响;得出较佳的工艺条件为反应温度85℃,反应时间2.5h,原料质量配比为m(CPP):m(MAH):m(BPO)=100:2.5:0.4.并对产物结构进行了FTIR表征.     

磺化腐植酸保水剂的制备及其性能研究

采用溶液聚合法制备了磺化腐植酸保水剂,探讨了影响磺化腐植酸保水剂制备的因素,采用扫描电镜、红外光谱和X射线衍射仪等手段对制备的保水剂进行表征,并用吸水倍数对保水剂在不同介质中的吸水时间、不同温度条件下的吸水性能和沙土的保水性能进行分析。结果表明:在磺化腐植酸投加量为0.3g、中和度为60%、n(KPS)/n(AA)为0.002、n(MBA)/n(AA)为0.0003时,其吸水倍数高达1034g/g;腐植酸在接枝前后,表面形貌发生变化,且其表面积明显增大;腐植酸接枝后具有丙烯酸的特征基团,磺酸基团可能被负载;腐植酸在磺化前后以及接枝前后性质发生了改变。所制保水剂在吸水2h后趋于饱和,在蒸馏水中的吸水效果最好,较低温度时吸水效果也较好。随使用时间的延长,在沙土中吸水倍数逐渐下降。     

改性CPP包装膜的研究

用甲基丙烯酸甲酯(MMA)对流延聚丙烯膜(CPP)进行接枝改性.系统研究了反应温度、反应时间、引发剂过氧化二苯甲酰(BOP)和单体MMA的量等因素对CPP膜接枝率的影响,并对其影响因素作了分析.实验结果表明改性以后的CPP膜性能得到提高,能满足多种包装膜的需要.     

正交设计法研究中温煤沥青磺化工艺

以浓硫酸为磺化剂对中温煤沥青进行磺化改性。采用硫酸钡沉淀法测其磺化度。通过考察反应温度、反应时间和磺化比对磺化度的影响并通过正交实验获得最佳工艺参数：反应温度70℃,反应时间5h,磺化比1．8,该条件下合成产物的磺化度达13．28％,水溶物含量为98％。     

Synthesis and characterization of sulfonated poly(ether imide) membranes using thermo-analysis and dialysis process

Polyimides have been investigated as alternative materials to commercial membranes, once these polymers present high thermal, chemical, and mechanical performances. This work has modified poly(ether imide), PEI, by sulfonation reaction using acetyl sulfate as sulfonating agent. Sulfonated PEI (SPEI) films were characterized by infrared spectroscopy, ion exchange capacity (IEC), glass transition temperature (Tg), and proton diffusivity. The influence of degree of sulfonation on IEC, Tg, and proton diffusivity can be observed. SPEI membranes have presented proton diffusivity lower than that obtained with a commercial sulfonated membrane (Nafion). This result was related to low degree of sulfonation and low chain mobility of the obtained SPEI.     

How to maintain the morphology of styrene-divinylbenzene copolymer beads during the sulfonation reaction

This work aims to describe the use of acetyl sulfate as sulfonating reagent of microporous beads based on styrene (STY) and divinylbenzene (DVB) which were prepared by aqueous suspension copolymerization. The copolymer was chemically modified by two different sulfonating agents, namely sulfuric acid and acetyl sulfate which is prepared “in situ” by mixing acetic anhydride and sulfuric acid. The morphologic features of resin beads were analyzed by optical microscopy (OM) and by scanning electron microscopy (SEM). The sulfonic group incorporation into the copolymer network was verified by infrared spectroscopy (FTIR) and quantified by using a standardized NaOH solution. The bead morphology maintenance depends on the sulfonating agent and reaction conditions.     

Preparation of sulfonated gel resins for use in ion chromatography

Conditions are studied for reproducibly sulfonating small, spherical poly(styrene-divinylbenzene) beads to obtain cation exchangers suitable for ion chromatography. The effects of wetting agents and sulfonation parameters are noted. Resin capacity is examined as a function of crosslinking under fixed sulfonation conditions. Sulfonated resins of the highest crosslinking studied (12%) are shown to be very efficient for ion chromatography. Electron-photomicrographs show that sulfonization occurs only on the outer surfaces of the spherical beads.     

The GC/AED studies on the reactions of sulfur mustard with oxidants

A gas chromatograph coupled with an atomic emission detector was used to identify and to determine the products formed on oxidation of sulfur mustard. The oxidation rate and the resulting oxidates were studied in relation to oxidant type and reaction medium parameters. Hydrogen peroxide, sodium hypochlorite, sodium perborate, potassium monopercarbonate, ammonium peroxydisulfate, potassium peroxymonosulfate (oxone), and tert-butyl peroxide were used as oxidants. Oxidations were run in aqueous media or in solvents of varying polarities. The oxidation rate was found to be strongly related to oxidant type: potassium peroxymonosulfate (oxone) and sodium hypochlorite were fast-acting oxidants; sodium perborate, hydrogen peroxide, ammonium peroxydisulfate, and sodium monopercarbonate were moderate oxidants; tert-butyl peroxide was the slowest-acting oxidant. In non-aqueous solvents, the oxidation rate was strongly related to solvent polarity. The higher the solvent polarity, the faster the oxidation rate. In the acid and neutral media, the mustard oxidation rates were comparable. In the alkaline medium, oxidation was evidently slower. A suitable choice of the initial oxidant-to-mustard concentration ratio allowed to control the type of the resulting mustard oxidates. As the pH of the reaction medium was increased, the reaction of elimination of hydrogen chloride from mustard oxidates becomes more and more intensive.     

Structure and Properties of Chemically-reduced Functionalized Graphene Oxide Platelets

Green reduction of graphene oxide(GO) functionalized with 3-aminopropyltriethoxysilane and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride/N-hydroxysuccinimide was performed by using ascorbic acid and sodium bisulfite.The obtained materials were characterized by thermo-gravimetric analysis,transmission electron microscopy.X-ray diffraction,UV-Vis,Fourier transform infrared and Raman spectroscopy techniques.The results indicated a strong dependence of the materials properties such as deoxygenation degree,absorption peak shift,crystallite size and functionalization degree on the functionalization approach and reducing agent.     

The Effect of Various Additives on the Stability of Isoproterenol Hydrochloride Solutions

The effect of various additives on the rate of degradation of eight isoproterenol hydrochloride aqueous formulations was studied. In addition, the reaction was studied at various pH values and temperatures. From the latter data, activation parameters were determined. Rate constants increased from 10 to 100 times over a 25 degree increase in temperature. The activation energy for the reaction averaged approximately 25 kcal/mole. Ascorbic acid and sodium bisulfite appear to be the most efficient antioxidants in the system. Sequestering agents such as EDTA and citric acid do not appear to reduce the rate and, in one instance, EDTA seemed to enhance the degradation process. The reaction appears to be an oxidation of the catechol ring system of isoproterenol similar to that observed with epinephrine.

Catecholamines such as isoproterenol and epinephrine are highly subject to degradative oxidation in solutions. A number of antioxidants and other substances are added to formulations containing these substances in an effort to retard this degradation. This study was undertaken to investigate the effect on the stability of the solutions. An attempt was also made to compare the interaction of isoproterenol with bisulfite and boric acid to the analogous interaction of the latter compounds with epinephrine.     

Reaction Kinetics of Some Catecholamines in Sodium Bisulfite Solutions

Decreases in isoproterenol and N-t butylnor-isoproterenol concentrations as a function of time have been measured for solutions with different sodium bisulfite concentrations. The pseudo first-order constants are dependent upon the sodium bisulfite concentration and the solution pH. The activation energy for isoproterenol and levarteronol in sodium bisulfite solutions was calculated as 24.4 and 25.0 kilocalories per mole. A minimum rate constant as a function of pH was demonstrated and the general equation was derived for this relationship.     

智能型AMPS/DMAEMA水凝胶的电敏感性能

以2-丙烯酰胺基-2-甲基丙磺酸(AMPS)和甲基丙烯酸N,N-二甲氨基乙酯(DMAEMA)为单体,N,N′-亚甲基双丙烯酰胺为交联剂,过硫酸铵和亚硫酸氢钠为氧化还原引发剂,采用水溶液聚合法制备了AMPS/DMAEMA水凝胶,考察了样品水凝胶在外加直流电场刺激下的消溶胀动力学和弯曲行为.结果表明,DMAEMA单体含量和施加电压大小对水凝胶的电敏感性能有着显著影响.用一级动力学方程能够较好地描述水凝胶在接触电压刺激下的消溶胀过程.在非接触电压刺激下,单体摩尔比,n(AMPS):n(DMAEMA)=9:1的水凝胶向负极弯曲;单体摩尔比n(AMPS):n(DMAEMA)=5:5的水凝胶向正极弯曲;单体摩尔比n(AMPS):n(DMAEMA)=7:3的水凝胶随着非接触电压的增大,出现先向负极弯曲,后向正极弯曲的现象.