耐温耐盐疏水缔合聚合物的合成及性能评价

以丙烯酰胺(AM)、疏水单体烯丙基十二胺和耐盐单体H-66为原料,通过自由基水溶液聚合制备一种聚丙烯酰胺类聚合物RDTA。通过1H NMR和FTIR表征聚合物结构,通过表观黏度、SEM和流变性能测试研究了RDTA在不同溶液中的缔合效应和该缔合行为随温度变化的影响关系。实验结果表明,RDTA的临界缔合质量分数(W*)在0.25% ~ 0.3%。盐离子对RDTA高分子链的刺激作用能够增强该分子链的结构黏度。弹性模量G′随RDTA质量分数的增加而增大,溶液体系表现出弹性体,体系的空间结构更加密集。70℃、90℃和120℃,170 s-1剪切下,0.5% RDTA在6% NaCl盐溶液中剪切时间 < 300 s时,溶液黏度呈现缓慢上升趋势,说明RDTA在NaCl盐溶液中存在盐刺激RDTA溶液增稠的现象,继续剪切1 h后,剪切剩余黏度仍60 mPa·s以上。     

一种耐高温酸液稠化剂的制备及性能

以丙烯酰胺(AM)、甲基丙烯酰氧乙基三甲基氯化铵(DMC)为原料、是否引入十八烷基甲基丙烯酸酯(SMA)为区别,通过自由基聚合制备出两种稠化剂SY-1和SY-2.采用FTIR及芘探针法对其结构进行表征;通过热重分析仪、流变仪、酸岩反应旋转岩盘仪对其进行性能测试.结果表明:引入SMA单体后制得产物SY-2热稳定性得到改善;当SY-2添加量为质量分数为20％的盐酸溶液质量的0.8％时,溶液升温至180℃的终点黏度为50 mPa·s,继续剪切1 h后终点黏度为20.1 mPa·s,剪切稳定性为40.20％;在180℃、3 MPa下,SY-2型稠化酸的静态酸岩反应速率为8.94×10–5 g/(cm2·s).该体系与缓蚀剂、铁离子稳定剂配伍性良好,可用于深井高温酸化压裂.     

耐盐型疏水缔合聚合物的制备及流变性能

采用丙烯酰胺(AM)、丙烯酸(AA)、2-丙烯酰胺-2-甲基丙烷磺酸(AMPS)和水溶性阴离子疏水单体S-18制备了新型耐盐疏水缔合聚合物S-18HPAM。聚合放热测试表明:疏水单体含量的增加导致放热时间的延长,更有利于疏水结构的形成。微观结构测试表明:聚合物具有复杂的网状结构,在NaCl溶液中网状结构更为明显。流变测试结果表明:聚合物在盐溶液中具有良好的耐温和抗剪切性能。聚合物质量分数为0.3%(基于溶液总质量),温度90℃,剪切速率170 s–1和NaCl质量浓度20000 mg/L条件下,剪切后表观黏度大于70 mPa·s。在总矿化度20000 mg/L模拟地下水条件下,S-18HPAM质量分数为0.3%,剪切后黏度为70 mPa·s,加入质量分数0.5%表面活性剂十二烷基硫酸钠(SDS)后,黏度增加到170m Pa·s。储能模量G'随着聚合物质量分数的增加而增大,体系弹性增强,同时疏水结构单元数量增加,形成致密的空间网络结构。     

一种疏水缔合聚合物的合成及溶液性能

将十八烷基-二甲基甲代烯丙基氯化铵(C18DMMAAC)作为疏水单体,与丙烯酸(AA)、丙烯酰胺(AM)在水溶液中通过自由基聚合得到疏水缔合聚合物HAPAM-18,通过1HNMR和红外光谱对其结构进行了表征。最佳的聚合反应条件为:n(AM)∶n(AA)∶n(C18DMMAAC)=74.94∶25∶0.06,AA的摩尔中和度为95%,单体总质量分数为20%,引发剂质量分数为0.05%(以单体总质量计),温度45℃,反应时间12 h。研究表明,聚合物溶液的临界缔合质量浓度为2 g/L;聚合物溶液对温度较为敏感,80℃时黏度保留率为70.93%;聚合物溶液仍为剪切变稀的假塑性流体,但表现出良好的抗剪切性能,剪切1 h后黏度保留率达115%;由于设计为含较多阴离子的聚合物,该聚合物的抗盐性较差。     

耐温耐盐疏水缔合水溶性聚合物的研究进展

疏水缔合聚合物相较于传统的聚丙烯酰胺由于其耐温耐盐稳定性好等特点成为近年来油田上主要的研究对象,本文就从国内外调研综述了疏水缔合聚合物的研究新进展,并从分子的主链、侧链等方面提出了提高疏水缔合聚合物耐温抗盐性能的途径,最后腱鬻了琉水缔合聚合物在油气开采、涂料、污水处理、药物缓释等广阔的应用前景．     

页岩压裂用疏水缔合聚合物的合成及性能分析

采用表面活性大单体法,在聚丙烯酰胺分子链上引入少量疏水基团,合成AM—AA．DM共聚体系,应用到页岩气压裂液中。考察了引发温度、引发剂用量、疏水单体含量等对聚合物性能的影响。结果表明,聚合的最佳条件为：引发温度40℃,引发剂含量0．1％,单体总浓度25．0％。在此条件下,聚合物的粘均分子量为112万左右,粒度主要分布在0．4—1．0μm之间,合成产物均一性较好;合成产物水溶液具有良好的抗剪切性能。     

耐温疏水缔合聚合高分子制备及流变性能研究

以丙烯酰胺（AM）?2-丙烯酰胺-2-甲基丙磺酸（AMPS）为原料,引入长链疏水单体DAB和刚性疏水单体Ars,采用自由基水溶液聚合得到耐温型疏水缔合聚合高分子PAS,使用红外光谱仪和扫描电镜表征PAS分子结构并观察分子链的聚集状态,使用热重仪测试聚合高分子的耐热性,RS6000流变仪测试PAS的流变性能并与常规疏水缔合聚合物对比。结果表明：PAS干粉372℃失重50%,具有良好耐热性;聚合高分子PAS具有复杂空间网络结构并观察到疏水侧链的缔合微区,经流变仪频率扫描与应力扫描,聚合高分子PAS表现出良好的触变性和黏弹性,聚合高分子PAS在170 s-1条件下耐温达150℃可保持121 mPa·s,在100℃条件下剪切1.5h,黏度为198mPa·s,经过不同速率剪切后黏度恢复率为78.5%,与常规的疏水缔合型聚合物相比具有更好的耐温性和抗剪切性能。     

纳米SiO2改性疏水缔合聚合物基的合成及性能评价

本文以丙烯酰胺(AM)、2-丙烯酰胺基-2-甲基丙磺酸(AMPS)和丙烯酸(AA)为亲水单体,十六烷基二甲基烯丙基氯化铵(CDMAAC)为疏水单体,在纳米SiO2的存在下,以EDTA/VA044/过硫酸铵/抗坏血酸为引发剂,通过自由基聚合法,合成了具有核壳结构的纳米SiO2改性疏水缔合聚合物.分别通过红外光谱和扫描电镜...     

疏水缔合聚合物的合成、表征及其溶液性能研究

采用自由基胶束聚合法,合成了一种疏水缔合型丙烯酰胺-烷基丙烯酸酯共聚物。用1HNMR谱和TEM对该共聚物进行了表征。用旋转黏度计测定了不同疏水基含量的聚合物的溶液性能,考察了温度对聚合物溶液性能的影响,同时研究了外加盐对聚合物溶液形貌的影响。     

一种疏水缔合型阳离子聚合物酸液稠化剂的合成及性能

以甲基丙烯酰氧乙基三甲基氯化铵(DMC)、甲基丙烯酰氧乙基二甲基正十六烷基溴化铵(HDMC)为原料,采用自由基水溶液聚合制备阳离子型疏水缔合聚合物P(DMC-HDMC)。用红外光谱、核磁共振氢谱和荧光光谱分别对其分子结构和疏水微区结构进行了表征,并对其在酸液中的流变性进行了考察。结果表明,P(DMC-HDMC)含有亚甲基长链(CH2)15,在溶液中能够形成疏水微区,且其临界缔合质量分数(CAC)为～0.17%(质量分数)。在w(HCl)=20%的溶液中,当w〔P(DMC-HDMC)〕=0.16%(CAC)时,其流出时间t分别为20.47 s和40.8 s;与非疏水缔合型聚甲基丙烯酰氧乙基三甲基氯化铵(PDMC)相比,随酸质量分数的增加,PDMC的黏度明显降低,而P(DMC-HDMC)则相对稳定,整体呈略微上升趋势;w〔P(DMC-HDMC)〕=1.0%时,在w(HCl)=20%溶液中60、90℃下的热稳定性ω分别为85.5%和70.4%;w〔P(DMC-HDMC)〕=0.8%时,w(HCl)=20%溶液中30℃、170 s-1下剪切120 min后剪切稳定性ω'为88.3%。     

耐高温有机锆交联酸体系性能研究

鉴于目前交联酸体系不能满足高温储层酸化压裂需要,以自制有机锆交联剂JLJ-11及稠化剂FS3802为原料,通过加量优选,制备了一种新型耐高温有机锆交联酸体系,并对其耐温耐剪切、滤失、缓蚀、携砂以及破胶等性能进行了评价。结果表明,所制备交联酸体系耐温耐剪切性能显著,在恒温150℃和剪切速率170 s-1条件下,持续剪切1 h,表观粘度仍保持在50 mPa·s以上;体系破胶彻底,加入0.2%的过硫酸铵,95℃静置2 h后,粘度降至2.15 mPa·s;同时所制备交联酸体系滤失系数较低、缓蚀作用明显、携砂性能良好,适用于高温储层的酸压施工。     

低伤害酸性压裂液的制备及性能测试

针对碱敏、高温、低渗地层,制备出了一种酸性交联的低伤害超支化压裂液体系。通过室内实验,确定了适合120¹40℃井的高温配方:0.4%140℃井的高温配方:0.4%⁰.6%超支化分子稠化剂+0.3%0.6%超支化分子稠化剂+0.3%⁰.6%交联剂+0.5%助排剂+0.5%粘土稳定剂+过硫酸铵,并对其进行了性能评价,结果表明,该压裂液体系具有良好的抗剪切性能、携砂性能,并具有破胶后无残渣、表面张力低、对地层伤害低等优点,可以满足储层改造工艺设计要求。     

耐高温厌氧胶的研制及其贮存稳定性研究

以乙氧化双酚A二甲基丙烯酸酯（BPA2EODPT）、环氧丙烯酸酯（EA）和三羟甲基丙烷三甲基丙烯酸酯（TMPTMA）为主要原料,N,N'-4,4'-二苯甲烷双马来酰亚胺（BMI）和气相二氧化硅（SiO2）为耐热改性剂,异丙苯过氧化氢（CHP）为引发剂,N,N-二乙基对甲苯胺（DPT）和糖精（SA）为促进剂和助促进剂,对苯醌（BQ）、乙二胺四乙酸四钠（Na4EDTA）和对苯二酚（HQ）为稳定剂,优选出耐高温厌氧胶的最佳配方。结果表明：当m(BPA2EODPT)︰ m(EA)︰m(TMPTMA)=3.1︰1︰2.5、w(BMI)=6%、w(SiO2)=4%、w(CHP)=3.5％、w(DPT)=0.4%、w(SA)=2%、w(BQ)=0.07%、w(Na4EDTA)=0.04%、w(HQ)=0.11%时,厌氧胶的综合性能较好,耐热性能及贮存稳定性能俱佳。     

耐酸纳米微球的研发及CO2驱封窜性能研究

针对长庆低渗透油藏CO₂驱出现的窜流难题,以丙烯酰胺(AM)、4-苯乙烯磺酸钠(SSS)和二甲基二烯丙基氯化铵(DMDAAC)为共聚单体,N,N’-亚甲基双丙烯酰胺(MBA)为交联剂,亚硫酸氢钠(SHS)和过硫酸铵(APS)为引发剂,通过反相微乳液聚合法研发了一种耐酸纳米微球(AR-NS)。采用红外光谱(FTIR)、扫描电镜(SEM)、热重(TG)及流变仪对产物的结构、形貌和性能进行了分析。结果表明,合成产物在乳液中为高分散度的纳米微球,其平均初始粒径为255 nm。在酸性地层水条件下,耐酸纳米微球的膨胀倍数为13.8倍而普通微球膨胀倍数仅为3.7倍;油藏温度85℃条件下、质量浓度为5 000 mg/L时耐酸纳米微球悬浮液黏度仅为0.56 mPa·s,具有优异的注入性;低渗裂缝岩心超临界CO₂驱封窜实验表明,耐酸纳米微球注入后裂缝性岩心的封堵率达95.41%,采收率提高了21.03%,耐酸纳米微球在低渗CO₂驱油藏中具有优异的封窜效果。     

含全氟己基基团的甲基丙烯酸酯共聚物的合成及性能对比

分别将几种含氟单体(FA)与甲基丙烯酸丁酯(BMA)、丙烯酸乙酯(EA)聚合得到三元共聚物,通过IR、DSC、GPC、TGA等测试手段分别对其涂膜性能进行了研究对比。结果表明,全氟己基侧链的引入能有效提高涂膜的拒水能力和耐高温性能;芳香环的引入提高了涂膜的硬度及耐高温性能。利用热场发射扫描电镜(OXFORD EDX)对聚合物薄膜截面的氟元素分布进行了分析,显示退火工艺有助于含氟基团更好的向涂膜表面迁移,氟元素沿膜截面呈梯度分布。     

Preparation of ultra-high temperature SiC–TiB2 nanocomposites from a single-source polymer precursor

SiC–TiB₂ ceramic nanocomposites are valuable ultra-high temperature materials, which are rarely prepared from preceramic polymers. In this work, we synthesized SiC–TiB₂ nanocomposites from a new preceramic polymer called titanium- and boron-modified polycarbosilane (TB–PCS). The polymer structure was characterized by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy. The structure, composition, and morphology of the resulting ceramic products were investigated by FT-IR, X-ray diffraction, and transmission electron microscopy. The elements of titanium and boron were incorporated into the preceramic polymer, and nanoscale TiB₂ and β-SiC grains generated in situ were detected in the pyrolyzed ceramic products at temperatures higher than 1400 °C. The new preceramic polymer presents a novel approach to preparing SiC–TiB₂ nanocomposites.     

Effect of temperature on mechanical properties of ultra-high performance concrete

High temperature mechanical property data are needed for evaluating fire resistance of structural members. Being a relatively new construction material, there is a lack of temperature-dependent mechanical property data on ultra-high performance concrete (UHPC). To address this knowledge gap, this paper presents results from an experimental study on the effect of temperature on mechanical properties of UHPC. Specimens made of two UHPC mixes: one with only steel fibers (UHPC-S) and the other with hybrid fibers, that is, both steel and polypropylene (UHPC-H), were tested under different heating conditions in 20 to 750°C temperature range. Compressive strength, tensile strength, stress-strain response, and elastic modulus of UHPC were evaluated at various temperatures. Results generated from these property tests on UHPC were compared with property relations specified in design codes for conventional normal strength concrete (NSC) and high strength concrete (HSC). The comparisons show that UHPC experiences faster degradation in compressive strength and elastic modulus as compared to conventional concrete. However, UHPC exhibits slower degradation in tensile strength and ductility at elevated temperatures due to the presence of steel fibers. Data generated from these property tests were utilized to propose relations for expressing the mechanical properties of UHPC as a function of temperature and these relations can be used as input to numerical models for evaluating fire resistance of structures made of UHPC.     

Thermal properties and performance of carbon fiber-based ultra-high temperature ceramic matrix composites (Cf-UHTCMCs)

The thermophysical properties of carbon fiber-based ultra-high temperature ceramic matrix composites have been determined to aid designers who need these properties when considering using the composites in ultra-high temperature aerospace applications. The coefficient of thermal expansion (CTE) and thermal diffusivity of the composites were measured parallel and perpendicular to the ply direction; the thermal conductivity was measured using the laser-flash method and the heat capacity calculated from the relationship between the thermal diffusivity, density, and thermal conductivity. Both the CTE and thermal conductivity showed higher values across the ply and increased with increasing temperature as expected, whilst the thermal diffusivity showed higher values parallel to the ply and increased smoothly with temperature. In addition, two different but related oxyfuel torch tests, based on oxyacetylene and oxypropane, were used to evaluate the thermo-ablation behavior of the composites. The tests showed how good the composites were at withstanding the ultra-high temperatures, high heat fluxes, and gas velocities involved.