纳米TiO2光催化降解含油污水中HPAM的研究

用溶胶-凝胶法制备了锐钛矿型纳米TiO2,研究了合成催化剂反应条件对光催化降解含油废水中聚丙烯酰胺(HPAM)的影响。确定了最佳反应条件分别为:煅烧温度在500℃时,光催化活性达到最高,随着煅烧温度的升高,催化剂晶型从锐钛矿向金红石型转化,转型温度为600℃,有金红石型晶体出现时催化活性降低;最佳老化时间约为1 d;随着醇用量的增加,制备出来的TiO2其光催化活性也逐渐升高,当V(钛酸丁酯)∶V(醇)=10:80时,催化剂活性最高,继续增加,催化活性降低;随着水量的增加催化活性增强,当V(钛酸丁酯)∶V(水)=100:40时,制备出的TiO2催化活性最大,继续增加催化活性下降。     

絮凝剂的助滤行为分析

对高分子絮凝剂（聚丙烯酰胺）在过滤过程中的作用进行了系统的动态研究，总结了絮凝剂在过滤过程中的行为规律。絮凝剂的助滤作用主要表现在过滤成饼阶段，脱水阶段也有利于部分毛细水排出，但随着脱水时间延长，滤饼水分往往高于未经絮凝的滤饼。     

Graft Copolymerization of Pectin with Polyacrylamide

In the present study, an attempt has been made to modify pectin by grafting polyacrylamide using ammonium ceric sulphate as initiator. The effect of various variables like initiator concentration, monomer concentration, temperature and time has been studied. The grafted copolymer was characterized by Fourier transform infrared spectroscopy (FT-IR), organic elemental analysis, differential scanning calorimetry (DSC) and X-ray diffraction (XRD). FT-IR studies indicated incorporation of amide group. Rheological behavior of pectin solution was compared with that of the grafted copolymer. The comparative rheological properties of pectin and grafted copolymer indicated change in the property of the product. Differential scanning calorimetry and XRD suggested formation of the grafted copolymer.     

多羟基稳定剂对聚丙烯酰胺分散聚合粒子形态的影响

以乙醇／水（EtOH／H2O）溶剂为反应介质,以过硫酸铵（AFS）和聚乙烯醇（PVA）或聚乙二醇（PEG）为引发剂和稳定剂,利用显微分析观察当改变稳定剂的种类时,丙烯酰胺（AM）分散聚合粒子形态的变化。研究发现：以PVA-0488,PEG-1000和FEG-2000为稳定剂时所得粒子为球状,而以PVA-1788或PVA-1799为稳定剂时所得粒子为短棒状。     

高温延迟交联聚丙烯酰胺凝胶堵漏剂的研究

利用热熔胶的热塑性,制备了热熔胶延迟引发剂。基于自由基聚合,以丙烯酰胺、N,N’-亚甲基双丙烯酰胺为单体合成了高温延迟交联聚丙烯酰胺凝胶堵漏剂。利用红外光谱和扫描电镜对高温延迟交联堵漏剂进行了结构表征,并对凝胶的成胶时间、封堵能力和抗温性能进行了测试。实验结果表明,引发剂成功被热熔胶包覆。此外,高温延迟交联堵漏剂性能评价实验表明,相比空白样,其可有效地延迟成胶时间,成胶时间为1～4 h可调;同时,该凝胶还具有优良的封堵性能,高温下可有效封堵4 mm缝宽缝板,承压4.83 MPa以上;凝胶具有良好的抗温能力,150℃热滚96 h后,破胶率仅5%。高温延迟交联凝胶保证了现场地下交联凝胶堵漏施工的顺利进行,可有效封堵裂缝型恶性漏失。     

反相悬浮聚合诱导微米级多孔SiO2微球的制备

以硅溶胶为硅源,采用聚丙烯酰胺作为结构导向试剂,反相悬浮聚合法制备了介孔二氧化硅微球。控制引发剂过硫酸钾、交联剂N,N-亚甲基双丙烯酰与单体丙烯酰胺的加入量,获得球形度以及分散性较佳的聚丙烯酰胺复合二氧化硅微球。焙烧去除聚丙烯酰胺模板后得到的二氧化硅微球通过光学显微镜、红外光谱FT-IR、X-射线衍射以及氮气吸附脱附等手段进行了表征,证明聚丙烯酰胺在制备中起到了良好的结构导向作用,获得的二氧化硅微球的比表面积为240m2/g,孔径均匀分布于9nm左右,孔容度为0.3cm3/g。该方法可以通过改变转速的方法控制硅球的粒径。     

超高相对分子质量聚丙烯酰胺特性粘数测定方法

针对流变性和粘弹性越来越复杂的超高相对分子质量聚合物,以牛顿流体为理论基础的毛细管粘度计测定特性粘数的方法误差越来越大。从分析胜利油田现场用超高相对分子质量聚合物的流变性能入手,通过测定聚合物溶液的粘温曲线、流变曲线和固定剪切速率下的粘度,确定了流变仪法在低剪切速率、低浓度下测定超高相对分子质量聚合物特性粘数的实验条件。结果表明,流变仪法测定的超高相对分子质量聚合物的特性粘数值与聚合物的相对分子质量更加接近,ηsp/C～C和lnηr/C～C曲线线性好,测定结果准确可靠。      

On the possibility of using combined polymerization and drying in synthesis of polyacrylamide

This paper presents investigation results of polyacrylamide synthesis with combined polymerization and drying. First, polyacrylamide synthesis was carried out in concentrated aqueous solutions of acrylamide at 30°C. Polymerization was initiated by K₂S₂O₈/Na₂S₂O₃ an oxidation–reduction system. The monomer conversion degree at this stage did not exceed 80%. Further, polymerization with simultaneous solvent elimination from the prepolymer was carried out in a dryer with infrared heat supply and natural convection. Such conditions provide monomer conversion degree up to 100%.     

Nonlinear optical properties of two oxazine dyes in aqueous solution and polyacrylamide hydrogel using single beam Z-scan

The nonlinear optical properties of the two oxazine dyes, i.e. oxazine 720 (OX720) and oxazine 750 (OX750), in aqueous solution and in polyacrylamide hydrogel (PAA) matrix were studied by Z-scan technique using CW He–Ne laser at 632.8 nm. All the polymeric and aqueous samples showed a negative nonlinearity and large nonlinear refractive index of the order of 10⁻⁸ cm²/W. The concentration-dependent nonlinear refractive index was also investigated. In the case of PAA–dye systems, two types of transit (fast) and steady state (slow) nonlinear effects were observed. It is believed that these effects are due to the thermo-optical induced refractive index gradient and a concentration gradient induced by a temperature gradient present in a medium.