Synthesis and performance evaluation of a new drag reducer based on acrylamide/12-allyloxydodecyl acid sodium

Hydraulic fracturing with slickwater is a field-proven stimulation technology used in tight reservoirs. Because of the high pumping rate associated with slickwater fracturing, drag reduction (DR) is critical in minimizing pressure drop and the success of oilfield operations. In this paper, a new type of drag reducer (SPR) was synthesized with acrylamide and 12-allyloxydodecyl acid sodium, and its drag reduction performance was evaluated. The results showed that the new drag reducer features low molecular weight, fast-dissolving rate and low interfacial tension. The algorithm of estimating the drag reduction rate of non-Newtonian fluid SPR was proposed and validated. Empirical or semianalytical models for estimating the friction ratio (σ) or friction factor (λ or f) were used to simulate the turbulence behavior of the SPR drag reducer under different Reynolds numbers (Re). The modified Virk's correlation could accurately model the turbulent behavior of the SPR drag reducer. A unified calculation formula was established in this study for different pipe diameters.     

丙烯酸/α-甲基丙烯酸/丙烯酰胺共聚物智能水凝胶的合成及评价

由丙烯酸（AA）、α-甲基丙烯酸（MAA）和丙烯酰胺（AM）合成了具有很好DH敏感性和一定温度敏感性的智能水凝胶，考察了合成温度、丙烯酰胺、交联剂和引发剂用量对制备的水凝胶溶胀性能的影响。结果表明，在60℃下，单体从和MAA用量分别为100mmol和75mmol时，单体AM、交联剂和引发剂用量分别为反应物总质量的32．8％、0．2％和0．4％时，制备的水凝胶溶胀性能最好。考察了介质的离子浓度、pH值和温度对水凝胶溶胀比的影响，结果表明，离子浓度越大，水凝胶的溶胀比越小；水凝胶具有一定的DH可逆性。     

N-苄基丙烯酰胺的合成

以丙烯腈和苯甲醇为原料，浓硫酸作催化剂，合成了N-苄基丙烯酰胺（N-BAA）。考察了反应温度、反应时间和催化剂用量等因素对产物收率的影响，得出了最佳反应条件：n（丙烯腈）：n（苯甲醇）：n（浓硫酸）=3：1：1．2，反应时间3h，反应温度60℃。在最佳条件下，N-BAA的收率可达92％。每100g粗产物用10％氢氧化钠溶液提纯，精制产物纯度可达99．80％，熔点为64～65℃。通过红外光谱对产物结构进行了表征。     

驱油用抗盐聚合物KYPAM的应用性能

新研制并已投入工业生产的驱油用抗盐聚合物KYPAM，为具有梳形分子结构的超高分子量的AM／AHPE共聚物（共聚单体AHPE结构未知）。按大庆企业标准《驱油用聚丙烯酰胺》的规定测定6项质量指标，KYPAM均优于大庆2B838和日本三菱MO－4000；在矿化度为1000－19334mg/L的大庆（45℃），胜利（70℃，80℃）5种清水，污水中，1000mg/L的KYPAM溶液的粘度较对比超高分子量HPAM高30％－40％；在不脱氧180小时溶液老化测试中，KYPAM粘度保持率最高，KYPAM溶液45℃剪切稳定性略高于2B838和MO－4000溶液；KYPAM在3种水中的增粘性能（粘浓曲线，45℃和70℃）均远好于2B838和MO－4000。在70℃岩心驱油实验中，KYPAM污水溶液提高水驱后采收的幅度，阻力系数和残余阻力系数均高于英国胶体公司的HPAM1285清水溶液。     

Preparation of glucose oxidase immobilized in different carriers using radiation polymerization

Glucose oxidase (EC 1.1.3.4) was immobilized on different polymeric materials using different immobilization techniques (entrapping by γ‐irradiation, and covalent binding using epichlorohydrin). Studies were carried out to increase the thermal stability of glucose oxidase (GOD) for different applications. The activity and stability of the resulting biopolymers have been compared with those of free GOD. The effect of different polyvinyl alcohol/polyacrylamide (PVA/PAAm) compositions of the copolymer carrier on the enzymatic activity of the immobilized GOD was studied. The maximum enzymatic activity was obtained with the composition ratio of PVA/PAAm of 60:40. The behaviour of the free and immobilized enzyme was analysed as a function of pH. A broadening in the pH profile (5.5–8) was observed for immobilized preparations. The activity and stability of the resulting biopolymers produced by immobilization of GOD onto different carriers have been compared, in both aqueous and organic media, with those of the free GOD. The enzyme's tolerance toward both heat and organic solvent was enhanced by immobilization onto polymers. The addition of different concentrations of organic solvents (10–50%, v/v) to the enzyme at higher temperature (60 °C) was found to stabilize the enzyme molecule. The strongest stabilizing effect on the enzymatic activity was achieved at a concentration of 10%. Copyright © 2005 Society of Chemical Industry     

N-羟甲基丙烯酰胺的合成

对N－羟甲基丙烯酰胺（NAM）的合成工艺做了进一步的研究。结果表明：在丙烯酰胺：甲醛＝1∶1．05（mol比），碱性催化剂存在下，70℃反应3h。转化率可达99％。产品质量稳定，反应液可不经分离直接用作交联剂，降低了生产成本。并提出用固含量法测定溶液中的NAM含量，简易可靠。     

Water-soluble copolymers: 22. Copolymers of acrylamide with 2-acrylamido-2-methylpropanedimethylammonium chloride: Aqueous solution properties of a polycation

The viscometric, turbidimetric and potentiometric properties of copolymers of acrylamide (AM) with 2-acrylamido-2-methylpropanedimethylammonium chloride (AMPDAC) were studied in aqueous solutions. The AMPDAC polymers exhibit poor salt tolerance and large, negative viscosity/temperature coefficients. Furthermore, the polymers were found to be sensitive to changes in pH. The AMPDAC polymers undergo phase separation in the presence of dianions as a function of temperature and AMPDAC composition.     

新型阳离子聚丙烯酰胺微粒的研究--含PEO支链阳离子聚丙烯酰胺微粒的合成、助留性能及作用机理

本文采用反相微乳液聚合的方法合成了丙烯酰胺(AM)/丙烯酰氧基乙基三甲基氯化铵(AD-AMQUAT)/聚氧乙烯大单体(PEO-A)/N,N'-亚甲基双丙烯酰胺(Bis)的四元共聚物微粒.研究了该微粒助留剂的结构与性能.这种微粒和纸纤维能够通过离子键和氢键作用显著地增强助留效果.     

Methacrylic acid–acrylamide-g-poly(ethyleneterephthalate) fibres for urea hydrolysis

This paper presents the results of urease immobilization onto methacrylic acid–acrylamide grafted poly(ethyleneterephthalate) fibres. The graft yield strongly affected the maximum activity of the immobilized enzyme up to a value of 70·2%. Higher grafting caused a decline in urease activity and led to the degradation of the fibres. The minor changes observed in K_m and V_max demonstrated that the conformational changes existed during immobilization were not extensive. However, 70·2% methacrylic acid–acrylamide-g-fibres containing urease were more stable towards acidic and alkaline pH, high temperature and storage conditions compared with free enzyme. Apart from the increase in stability to heat inactivation, the initial enzymatic activity of the urease–fibre system remained almost unchanged even after 40 repeated assays corresponding to 10 h of operation in 4 months, indicating the excellent durability of the system.