疏水缔合减阻剂的分子模拟

采用分子模拟软件Materials Studio2017R2分别构建非离子型疏水改性聚丙烯酰胺(HM-PAM)、部分水解水溶性疏水缔合聚丙烯酰胺(HAWSP)、部分水解阴离子型聚丙烯酰胺(HPAM)溶液模型,通过分子动力学模拟的方法来计算HPAM、HAWSP与HM-PAM类聚合物在不同Na Cl浓度下的回旋半径(Rg)、均方位移(MSD)。从模拟结果来看,HAWSP与HMPAM、HPAM相比具有更大的回旋半径、更大的特性黏数、更大的流体力学尺寸,会产生更好的减阻效果。在室内采用流体流动阻力测试仪测定HPAM、HAWSP与HM-PAM减阻聚合物在不同Na Cl浓度、不同剪切条件下的减阻性能。实验结果表明,HAWSP型聚合物减阻效果良好,与HM-PAM、HPAM相比具有更好的耐盐性、抗剪切性,与模拟结果一致。     

疏水缔合聚合物溶液的性能

疏水缔合水溶性聚合物指在常规水溶性聚合物主链上引入极少量疏水基团所形成的一类新型聚合物。与部分水解聚丙烯酰胺(HPAM)相比,这类聚合物的分子量不高,但具有独特的溶液性能。本文综述了疏水缔合聚合物的增黏、耐温、抗盐、抗剪切的溶液性能。     

矿化度对疏水缔合聚合物溶液溶解时间的影响研究

疏水缔合聚合物是在亲水的聚丙烯酰胺大分子主链上引入少量疏水基团合成的新型水溶型聚合物。其有耐温耐盐的良好特性。但是疏水基的引入降低了聚合物的水溶性,增加了溶解时间。本文以渤海某油田地层水的离子构成作为参考,通过配制不同矿化度溶液来溶解疏水缔合聚合物,探索矿化度对疏水缔合聚合物溶液粘度及溶解时间的影响,并从原理上解释了出现这些现象的原因。最终发现,随着矿化度升高,疏水缔合聚合物溶液粘度降低,溶解时间增大。这种现象是由于矿化度升高,溶液中电解质增多,溶液极性增强,影响了疏水缔合聚合物分子的展开和缔结。     

疏水改性聚丙烯酰胺的合成方法研究进展

疏水改性聚丙烯酰胺(HMPAM)作为疏水缔合水溶性聚合物重要的分支,具有增黏性、抗盐性和抗剪切性等特性,为研发低成本的HMPAM,以解决工业废水高效处理的问题,通过分析共溶剂法、胶束共聚法、乳液聚合法、自由基界面聚合法、超声波聚合发和超临界CO_2聚合法等HMPAM合成方法,明确了现阶段各种合成方法存在研发生产周期长、成本高、合成效率低和处理效果差等问题,提出将计算机模拟技术和试验结果相结合,完善合成单体和合成方法的搭配系统,寻求更科学、快速和低成本的HMPAM合成方法。     

疏水缔合聚丙烯酰胺溶液性质研究

用粘度法和核孔膜过滤法研究了实验室自制相对分子质量约1000万的疏水缔合聚丙烯酰胺(HAP)溶液的缔合效应,用粘度计考察了电解质浓度、温度和剪切速率对HAP溶液表观粘度的影响,并与相同测试条件下相对分子质量为1770万的部分水解聚丙烯酰胺3530进行对比。结果表明:HAP溶液在70℃的高温和矿化度为5727的高盐条件下,在1000mg/kg附近存在一临界缔合浓度,在临界缔合浓度以上,HAP溶液粘度迅速增加;而3530不存在临界缔合浓度,粘度增加缓慢。浓度为1250mg/kg的HAP溶液通过核孔膜20mL的过滤时间是347.3min,而相同浓度下3530的过滤时间仅为2.1min。浓度为1000mg/kg的HAP溶液即使在矿化度为30000、70℃的高温、30r/min转速的条件下,粘度仍达到32.8mPa·s,而聚合物3530的粘度仅有4.11mPa·s;当剪切速率增加到140r/min、温度为70℃,用矿化度为5727的模拟采出水配制的HAP溶液的粘度为9.21mPa·s,而3530溶液的粘度仅5.18mPa·s。HAP具有良好的耐温抗盐抗剪切能力。     

一种温敏型调剖剂体系的合成及表征

采用自由基胶束聚合,通过丙烯酰胺与甲基丙烯酸十二烷基酯的反应,制备得到了疏水链段在主链上嵌段分布的疏水改性聚丙烯酰胺(HMPAM),随后采用乌氏粘度计、核磁共振等方法对其分子结构、分子量、疏水取代度以及嵌段疏水基团的平均长度进行了表征和分析。     

疏水性聚丙烯酰胺的合成实验研究

疏水性聚丙烯酰胺是一种重要的疏水缔合水溶性聚合物,它可以通过多种方法合成。本文结合均相共聚法和表面活性大单体法2种方法,以丙烯酸和Span80为原料首先合成了一种具有表面活性的疏水缔合型单体Span80-AA,然后将Span80一AA与丙烯酰胺聚合反应合成疏水性聚丙烯酰胺,并研究了时间、引发剂浓度、溶剂配比、大单体含量和温度对疏水聚合物粘度和分子量的影响,从而得到比较合适的实验条件。     

长链疏水缔合聚丙烯酰胺的合成及其溶液性能与室内驱油效果

通过超声辅助,长脂肪链疏水单体丙烯酸十八酯(ODA)与丙烯酰胺(AM)和2-丙烯酰胺基-2-甲基丙磺酸(AMPS)共聚,得到疏水缔合聚丙烯酰胺(OPAM)。通过FTIR,TGA和XRD对聚合物进行了表征,结合表观黏度法和紫外光谱法测试了OPAM的溶液性能,并且进行室内模拟驱油实验。结果表明,OPAM临界缔合浓度(cac)为0.27%(质量分数),溶液在浓度高于cac时,有大量疏水微区形成。引入疏水单体ODA,聚合物热稳定性升高,结晶性下降。OPAM比常规高相对分子质量聚丙烯酰胺(HPAM)驱油效果更好,同等条件下,OPAM驱油效率比HPAM提高了5.5百分点。     

超高分子量聚丙烯酰胺水解干燥条件的研究

分析了聚丙烯酰胺水解、干燥过程中影响分子量及溶解性的主要因素。通过实验,对影响聚丙烯酰胺分子量的水解剂、水解温度、水解时间、水解浓度、胶体粒度、水解加热方法以及干燥时间、干燥温度等因素进行了优化选择,确定了聚丙烯酰胺后水解的工艺参数。并以此工艺参数为基础,确定了适合工业化生产的超高分子量聚丙烯酰胺水解及干燥条件。     

超临界CO2下含氟疏水缔合聚合物驱油剂的合成及性能研究

设计聚合物的分子结构并在超临界CO2下以丙烯酰胺（AM）、马来酸牛磺酸单酰胺化产物（MTS）及甲基丙烯酸十二氟庚酯（G04）为单体合成含氟疏水缔合聚合物驱油剂。并用FTIR、1HNMR和扫描电镜表征了结构。研究温度、压力对产物转化率的影响,含氟疏水聚合物浓度、溶液矿化度、体系温度等对溶液表观粘度的影响。结果表明：与传统聚丙烯酰胺驱油剂相比该聚合物具有很好的增粘效果,且耐温抗盐性能优良,其性能可以满足高温、高矿化度聚合物驱油的要求。     

Study of the interactions between hydrophobically modified polyacrylamide and poly(N-isopropylacrylamide) in water by polymer solvent method

Summary The hydrophobic interactions between poly(N-isopropylacrylamide), PNIPAM, and hydrophobically modified polyacrylamide, HMPAM, have been investigated by means of the polymer solvent viscometry method in dilute solutions. When HMPAM aqueous solution is used as a solvent, a divergence from linearity between the reduced viscosities of PNIPAM (as a solute) and C_PNIPAM is observed. While PNIPAM aqueous solution is used as a solvent, the linearity is better and the intrinsic viscosity of HMPAM is higher than that in 0.1 M NaCl. The magnitude of mutual interaction parameter K_AB suggests the presence of the hydrophobic interaction between HMPAM and PNIPAM, which is dependent on the hydrophobic groups content of HMPAM and temperature. Especially, as temperature increases from 25 to 30°C, the degree of hydrophobic interactions is enhanced, as is reflected in the Huggins coefficient K_H of HMPAM increase from 1.954 to 7.987.     

Properties of hydrophobically modified polyacrylamide with low molecular weight and interaction with surfactant in aqueous solution

Hydrophobically modified polyacrylamide (HMPAM), with a molecular weight of 10⁴ g/mol, was studied using a range of rheological methods and dynamic light scattering (DLS). DLS measurements indicate that the association of the modified polymer begins at low concentration. The modified polymer with high substitution forms transient networks below the critical concentration, but the networks are disrupted by the micelles formed by the polymer itself, and the networks do not contribute to viscosity enhancement. The modified polymers exhibited surface activity, and so they may be regarded as nonionic polymeric surfactants rather than thickeners. On the other hand, HMPAM is shown to interact with the surfactant SDS while PAM is inert to SDS. In the hydrophobic domains, it undergoes a surfactant‐induced association process; in the hydrophobe‐surfactant transition regions, the surfactant binds to the polymer in a noncooperative way and forms a polymer–surfactant complex. Contracted polymer chains begin to extend because of electrostatic repulsion, which can overcome the association at surfactant domains. The conformation of HMPAM polymer chains could be controlled by adding a specific amount of surfactant. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4348–4360, 2006     

部分水解聚丙烯酰胺N-羟甲基化反应的研究与产物结构表征

研究了部分水解聚丙烯酰胺与甲醛的N-羟甲基化反应和N-羟甲基化产物溶液的粘度行为，并对产物结构进行了表征。结果显示：HPAM与甲醛的羟甲基化反应除受反应温度、反应时间、投料比等因素影响外，聚合物浓度、水解度对羟甲基化程度也有明显影响。HPAM的羟甲基化反应在n(甲醛)：n(PAM)=1：1，温度60℃，pH=8-10，反应2h，羟甲基化率可接近50％。IR分析表明所得产物为部分水解羟甲基化聚丙烯酰胺。     

低黏度二苯基甲烷二异氰酸酯型聚氨酯预聚体的合成

为了研究不同反应条件对聚氨酯预聚体(PPU)产品的黏度和贮存稳定性这两方面的影响,并探究获得低黏度、高储存稳定性的PPU的合成工艺,以二苯基甲烷二异氰酸酯(MDI)和聚丙二醇(PPG)为原料,考察了聚合温度以及加料方式对聚合反应和预聚体黏度的影响。结果表明,对于直接使用的预聚体,适当降低聚合温度和延长滴加时间有利于降低产品黏度;对于需要储存一段时间使用的预聚体,适当提高聚合温度和一次性加料有利于降低体系黏度,稳定性更好。     

SiO2溶胶的甲基化改性及其性能研究

采用溶胶-凝胶法,以甲基三乙氧基硅烷(MTES)为疏水性前驱物,对SiO2溶胶进行甲基化改性,制备MTES-SiO2溶胶,考察了MTES的加入对SiO2溶胶化学结构和性能的影响.结果表明,随着MTES加入量的增加,溶胶的粘度减小,凝胶时间延长,溶胶粒径略微增大.红外光谱分析表明,MTES-SiO2溶胶以Si -O - Si键为主,体系中已成功引入Si - CH3基团,所形成的SiO2分子具有线型结构.MTES-SiO2溶胶在陈化过程中,在粘度发生急剧改变前,溶胶的粘度、固含量变化不大,溶胶粒径略有增加.随着凝胶点的接近,溶胶分子逐渐由线型结构过度到三维网络结构.     

Preparation and stability of aqueous acrylic polyol dispersions for two-component waterborne polyurethane

In this study, aqueous acrylic polyol dispersions with high stability for a two-component waterborne polyurethane were prepared. To improve the stability of acrylic dispersions, the influence of the acrylic acid (AA) addition method, neutralization, water addition rate during the dilution process, and dispersion equipment on the stability of the aqueous acrylic polyol dispersion was studied using dynamic light scattering and a thermal storage experiment. The acrylic resins’ structure was examined using Fourier transform infrared spectra, and the water resistance of the resultant films was investigated by electrochemical measurements and a water-swelling experiment. The dispersions prepared by two-step AA addition exhibited better particle size distribution, viscosity, and thermal storage compared with those prepared by one-step AA addition. Furthermore, the acrylic resin prepared by two-step AA addition was observed to possess a higher acid value. The corrosion currents of films based on dispersions prepared by two-step AA addition decreased to a smaller extent after 24 h of immersion in water. The dispersions afforded smaller particles when larger amounts of neutralizer and slower water addition rates were used. The dispersions prepared using a sawtooth disk dispersion machine displayed better performance than that prepared using a homogenizer dispersion machine.     

Novel,rosin‐based,hydrophobically modified cationic polyacrylamide for kaolin suspension flocculation

A novel, hydrophobically modified cationic polyacrylamide (HMPAM) was synthesized via the copolymerization of acrylamide, diallyl dimethyl ammonium chloride (DMDAAC), and diallylmethyl dehydroabietic acid propyl ester ammonium bromide. Optimum conditions for preparing HMPAM were such that the amount of initiator was 0.075 wt % of the total monomer mass, the monomer concentration was 20 wt %, and the amount of DMDAAC was 18 mol % of the total monomer molar mass. HMPAM was characterized with an UV–visible spectrometer, ¹H‐NMR, Ubbelohde viscometer, rotational viscometer, and rotational rheometer. HMPAM solutions exhibited strong hydrophobic associations, and the critical association concentration of the HMPAM aqueous solution was about 0.7 wt %; the HMPAM solutions also showed salt thickening and shear resistance. The surface morphologies of the freeze‐dried HMPAM samples (1 wt %) were also observed via scanning electron microscopy. Compared with unmodified cationic polyacrylamide, Synthesis of HMPAM‐0.5 exhibited a stronger flocculation capacity, and the optimal transmittance of the supernatants was above 95%. HMPAM‐0.5 showed significant flocculation performances for 3–4 and 3–5 wt % kaolin suspensions at 40 and 50 mg/L, respectively. Moreover, the flocculation performance was enhanced with the addition of NaCl and CaCl₂. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46637.     

Preparation of PET/clay nanocomposites via in situ polymerization in the presence of monomer‐activated organoclay

Various polyethylene terephthalate (PET)/clay nanocomposites containing a commercial organoclay (organophilic montmorillonite nanoclay [OMMT]) and a monomer‐activated OMMT (remodified OMMT) were prepared via in situ interlayer polycondensation of dimethyl terephthalate and ethylene glycol. In order to remodify the commercial OMMT nanoparticles, a diacid chloride monomer was applied. The prepared nanocomposites were characterized by diverse methods, including X‐ray diffraction, differential scanning calorimetry, thermogravimetric analysis, and intrinsic viscosity measurements. The results of the study revealed that the PET/(remodified OMMT) nanocomposites possess a better state of clay dispersion as well as significantly better thermal properties as compared with the PET/OMMT nanocomposites. Moreover, the PET/(remodified OMMT) nanocomposites showed higher crystallization temperature, degree of crystallinity, maximum degradation temperature, and lower half‐time of crystallization than that of the PET/OMMT nanocomposites. It was found that the remodification process for OMMT led to less of a foaming problem during in situ polymerization. J. VINYL ADDIT. TECHNOL., 21:70–78, 2015. © 2014 Society of Plastics Engineers     

有机硅改性酚醛树脂胶粘剂压制稻秸杆人造板的研究

采用有机硅改性酚醛树脂(PF)胶粘剂压制稻秸秆人造板。经大量预试验后,采用正交试验法优选出制备稻秸秆人造板的最佳工艺参数。结果表明:当PF合成过程中温度(第二次增长黏度时)为80℃、w(有机硅)=5%和有机硅在第一次增长黏度之前加入时,由有机硅改性PF胶粘剂压制的稻秸秆人造板,其各项力学性能均满足GB/T 4 897.3-2003标准要求,甲醛释放量均低于0.5 mg/(100 g)。     

响应面优化法研究果糖苯酚树脂胶黏剂的合成

以果糖代替甲醛,在碱性条件下合成了果糖苯酚树脂胶黏剂。用响应面优化法对果糖苯酚树脂的合成条件进行了优化。以树脂黏度为考察指标,根据Box-Behnken的中心组合设计原理对实验进行设计和结果分析。用响应面优化法研究了温度、时间和催化剂用量对反应的联合影响,得出最佳工艺条件为:反应温度72.36℃,反应时间6.96h,催化剂用量7.98%。在此条件下,树脂的黏度为27.67s。同时用红外光谱(IR)对树脂结构进行了分析。