Swelling and Deswelling Kinetics of AT-O3S Polymer

In the oil industry, techniques decreasing unwanted water production have drawn large amounts of interest from many companies. During water injection operations, water is injected into the oil reservoir to extract oil trapped in the formation. Due to the heterogeneity in the reservoir formation, oil production will decline and water production will increase as the injected water sweeps the high permeability zones. In order to flush out the oil remaining in the low permeability zones, many treatments have been used. One such treatment involves the injection of an SAP （superabsorbent polymer） into the high permeability zones. The swelled polymer will decrease the heterogeneity of reservoir permeability, thus forcing water injection into the oil rich, unswept zones/areas of the formation. Proper application of an SAP can have a dramatic impact on both the production and lifespan of mature oil wells. Successful treatment is reliant upon the reservoir salinity, temperature, and pH.

Investigation of Swelling/Sorption Characteristics of Highly Swollen AAm/AMPS Hydrogels and Semi IPNs with PEG as Biopotential Sorbent

The aim of this study was to investigate the equilibrium swelling and sorption properties of chemically crosslinked copolymeric hydrogels as biopotential sorbent consisting of acrylamide (AAm) and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS). Semi-interpenetrating polymer network (semi IPNs) hydrogel, composed of AAm with AMPS as co-monomer, with poly (ethylene glycol) (PEG) and a multifunctional crosslinker such as trimethylolpropane triacrylate (TMPTA) was prepared. AAm/AMPS hydrogels and AAm/AMPS/PEG semi IPNs were synthesized by free radical solution polymerization by using ammonium persulphate (APS)/N,N,N’,N’-tetramethylethylenediamine (TEMED) as redox initiating pair. Swelling experiments were performed in water, 0.01 M and 0.03 M aqueous urea solutions at 25oC, gravimetrically. The hydrogels showed enormous swelling in aqueous urea/water medium and displayed swelling characteristics that were highly depended on the chemical composition of the hydrogels. FTIR spectroscopy was used to identify the presence of different repeating units in the semi IPNs. Some swelling and diffusion characteristics were calculated for different semi IPNs and hydrogels prepared under various formulations. For sorption of cationic dye, Lauths violet into the hydrogels was studied by batch sorption technique at 25oC. Dye removal capacity, adsorption percentage and partition coefficient of the hydrogels was investigated. Swelling and dye sorption properties of AAm/AMPS hydrogels and AAm/AMPS/PEG semi IPNs were investigated as a function of chemical composition of the hydrogels.

Preparation and Swelling Behavior of L-Lactide Interpenetrating Networks

Novel triblock copolymers of poly (L-lactide)-poly (ethylene glycol)-sebacate-poly (ethylene glycol)-poly (L-lactide) were synthesized by Ring-Opening Polymerization of different ratios of L-lactide with other three pre-prepared poly (ethylene glycol)-sebacate-poly (ethylene glycol) polymers, coded A, B and C which had different poly (ethyleneglycol) chain lengths. The copolymers were characterized by FTIR and 1H NMR spectroscopy, which indicated that the reaction of ROP took place and led to producing nine triblock copolymers having new different lactide chain lengths (n = 10, 25 and 50), AL10, AL25, AL50,BL10, BL25, BL50, CL10, CL25, and CL50. Nine polymer networks were also prepared from copolymers with sodium alginate S1 - S9 and finally mixed with a solution of hydroxyl ethyl cellulose to form SH1 - SH9.

疏水改性微球的制备及其膨胀性能与应用研究

通过反相乳液聚合法制备了一种疏水改性P(AM-N)微球.采用傅里叶变换红外光谱(FTIR)、热重分析仪(TGA)、扫描电镜(SEM)、流变及岩心驱替实验对所合成微球的结构、形貌、性能以及封堵效果进行了表征与测试,并考察了溶胀时长、温度和不同盐溶液浓度对P(AM-N)微球性能的影响.测试结果表明,P(AM-N)微球的平均粒径为76.42 nm,溶胀5 d后P(AM-N)微球的膨胀率高达17.21倍;在70℃下,P(AM-N)微球老化2 d后溶胀率高达17.14倍,在20000 mg/L NaCl溶液和2000 mg/L CaCl_(2)溶液中分别溶胀3 d后膨胀率高达5.31倍和6.03倍,说明其具有较好的耐温性和抗盐性;在注入量为0.5%的条件下,P(AM-N)微球封堵率可达到97.98%,与P(AM)微球相比具有更好的封堵性且弹性增强.

姜黄素-聚苯乙烯载药微球制备及其药物释放的研究

以苯乙烯为原料,分别采用种子溶胀法、悬浮法制备聚苯乙烯多孔微球,以聚苯乙烯多孔微球为载体,姜黄素为负载药物,制备出姜黄素-聚苯乙烯载药微球。考察微球质量、负载药物浓度、反应时间对微球载药率以及包封率的影响。结果表明,悬浮法、种子溶胀法制备的微球均有较好的载药功能,但种子溶胀法制备的多孔微球在载药和释药方面的效果更加显著。释放率试验分析,在10 h内累计缓释率仅达到18.2%,未出现突释的现象,该材料具有药物缓释的作用。

Numerical Simulation of Viscoelastic Extrudate Swell Through Elliptical Ring Die

The numerical simulation of extrudate swell is significant in extrusion processing.Precise prediction of extrudate swell is propitious to the control of melt flow and the quality of final products.A mathematical model of three-dimensional（3D）viscoelastic flow through elliptical ring die for polymer extrusion was investigated.The penalty function formulation of viscoelastic incompressible fluid was introduced to the finite element model to analyze 3D extrusion problem.The discrete elastic viscous split stress（DEVSS）and streamline-upwind PetrovGalerkin（SUPG）technology were used to obtain stable simulation results.Free surface was updated by updating the streamlines which needs less memory space.According to numerical simulation results,the effect of zero-shear viscosity and elongation parameter on extrudate swell was slight,but with the increase of volumetric flow rate and relax time the extrudate swell ratio increased markedly.Finally,the numerical simulation of extrudate swell flow for low-density polyethylene（LDPE）melts was investigated and the results agreed well with others’work.These conclusions provided quantitative basis for the forecasting extrudate swell ratio and the controlling of extrusion productivity shape.

EFFECT OF GAMMA RAYS IN THE PREPARATION OF POLYMER AND HYDROGEL FROM ACRYLAMIDE MONOMER

The formation of polymer and hydrogel from aqueous solutions having 20, 30 and 40% concentrations ofacrylamide monomer by γ-ray irradiation processing in the dose range 0.06-30 kGy using a Co-60 source and theircharacterization have been observed. Polymer conversion and gel fraction are found to depend on radiation doses. Polymerconversion increases with the increase of dose, depending on the solution concentration, where maximum conversion isachieved at 0.18, 0.16 and 0.10 kGy for 20%, 30% and 40% concentrations, respectively. On the other hand, gel fractionincreases with dose from the gel point (0.12 kGy) for all concentrations, where 100% conversion of gel occurs at doses≥5 kGy. Tensile strength, viscosity and molecular weight (M_w) of polymer samples increase with both the dose and theconcentration, showing a high value of M_w up to≈10~8. Swelling of hydrogels under water with respect to time varies due tothe variation of cross-linking density formed in the gels and the maximum swelling mainly occurs within 24 h. A remarkable change of surface morphology reveals characteristic features of monomer, polymer and hydrogel films.

A Novel Design Strategy for Temperature-Responsive IPN Hydrogels Based on a Copolymer of Acrylamide and N-(1,1-Dimethyl-3-Oxobutyl)-Acrylamide

A methology is described for the synthesis of novel temperature-responsive interpenetrating polymer network (IPN) hydrogels with poly(2-acrylamido- 2-methylpropane sulfonic acid) (PAMPS) as a tightly crosslinked 1st network, temperature-responsive poly(acrylamide-co-N-(1,1-dimethyl-3-oxobutyl)- acrylamide) (P(AM-co-DAAM)) with low cost as a lossely crosslinked 2nd network. The structure and morphology of the IPN hydrogels were characterized by FTIR, TGA and SEM, and the results indicated that PAMPS network introduced P(AM-co-DAAM) hydrogels have large, thermally stable and interconnected porous network. The properties of the IPN hydrogels, which include: swelling capacity, equilibrium swelling/deswelling ratio, temperature- responsive behavior, and the dwelling kinetics as specific temperature, were investigated carefully. Results showed that the obtained IPN hydrogels displayed a controllable equilibrium swelling/deswelling behavior and possessed remarkable thermosensitivity. In addition, the results also indicate that the incorporation of the hydrophobic groups DAAM has a big effect on the LCST of the IPN hydrogels. Consequently, these novel temperature-responsive IPN hydrogels with low cost and slow-releasing performance would be promising for potential applications, such as environmental catalysis, water treatment, and agriculture.

一种阳离子型聚合物防膨剂的制备与性能研究

以丙烯酰胺(AM)、二甲基二烯丙基氯化铵(DMDAAC)和甲基丙烯酰胺丙基三甲基氯化铵(MAPTAC)为原料,采用水溶液聚合法制备出一种阳离子型防膨剂PMAD,通过FTIR进行表征,并对其粘均分子量进行测试;由防膨测试、耐温测试、耐水洗测试、耐盐测试及其与无机盐复配实验,对PMAD的相关性能进行研究。结果表明,PMAD具有较好的防膨性能、耐温性能、耐水洗性能和耐盐性能。当PMAD使用浓度为0.8%时,其防膨率可达87.12%,温度为100℃时防膨率超过80%,矿化度为200 g/L时,防膨率大于90%,三次水洗后,防膨率保持在80%以上。将PMAD分别与KCl、NH_(4)Cl进行复配,在使用浓度为1%时,体系的防膨率均大于90%,表明PMAD具有优异的抑制粘土膨胀的作用。

Effects of synthesis parameters on the performance of crosslinked Co-polymers with clays for conformance control

Conformance control or water shut-off is a technique used to improve oil recovery.During conformance control,polymers block high permeability water areas and redistribute water drive toward unswept oil zones.In this study,co-polymers(denoted ATP-PGV/AM-co-AMPS)were synthesized using acrylamide(AM)and 2-acrylamide-2-methylpropane sulfonic acid(AMPS)as the monomers,polyethylene glycol(PEG)-200 and methylenebisacrylamide(MBA)as the crosslinkers,attapulgite(ATP)and bentonite(PGV)as the clay types,and ammonium persulfate(APS)as the initiator,in addition to paraffin oil and surfactants.Samples were synthesized using inverse emulsion polymerization with different concentrations of monomers,crosslinkers,and clays,and they were characterized using Fourier-transform infrared(FTIR)spectroscopy and scanning electron microscopy(SEM)with energy dispersive X-ray spectroscopy(EDX).FTIR spectra of the samples confirmed the existence of sulfonate and hydroxyl groups,which are important for polymer swelling.SEM-EDX images indicated that the morphology and elemental composition were different before and after swelling,confirming the occurrence of swelling.Moreover,samples were placed in sodium chloride solution(20,000 ppm)for 7 days to evaluate swelling at both room temperature and 90°C.Thermogravimetric analysis(TGA)and differential scanning calorimetry(DSC)were used to determine the thermal characteristics of the microparticles.Finally,rheological measurements were used to assess the deformation and rheological behavior of the hydrogels.The results showed that after 1 day,good swelling without loss of mechanical strength was achieved with the composite synthesized using 10%AM,15%AMPS,6%PGV,and 10%ATP.

Swelling Process of Thin Polymer Film Studied via in situ Spectroscopic Ellipsometry

The swelling process of thin polystyrene films in quantity was studied in this paper using the in situ spec- troscopic ellipsometry. We systematically investigated the influence of film thickness on the swelling process of thin polystyrene films. The results show that in the case of high Mw polystyrene（Mw=400000）, the curve of the swelling degree as a function of time discloses that the relaxation of the long polymer chains accompanies the diffusion of acetone molecules, The swelling process is via the Fickian relaxation mechanism. Both the values of the equilibrium swelling degree and the diffusion coefficient of acetone molecules in the polystyrene film decrease as the film thick- ness reduces under confinement. However, in the case of lowMw PS（Mw=4100）, the dewetting process is so fast be- fore the equilibrium of swelling that the whole swelling process cannot be observed.

Cohesional Entanglement of Amorphous Polymer in Glass State as Probed by Equilibrium Swelling in a "Non-Solvent

The equilibrium swelling of the system Polystyrene (PS) (M = 1.7 × 10s, monodisperse)/diethyl ether at 30 °C and 35 °C has been studied in detail in quiescent state for a time span over 150 d. Arguments are given to show that the swelling process in a “non-solvent” is a network swelling rather than a phase separation process. It is different from the cloud point curve (CPC) experiment studied in literature, where the experiment starts from a one-phase solution, so that the cohesional entanglement present in the solid polymer is disrupted by dissolution. The cohesional entanglement structure of the solid polymer, on the contrary, is retained in the concentrated phase on swelling, at least in the initial stage. The course of swelling as presented by the curve Va(t) was found to proceed in three stages, where Va is the volume of the concentrated phase. In the first and third stages of Va(t), the curve goes up smoothly, while in the second stage the curve Va(t) shows large up and down jumps, indicating probably a readjustment in the network structure. Some results on a monodisperse PS sample of M = 5.8 × 105 and a polydisperse sample of M = 2.0 × 105 are also given. The values of Va observed at swelling equilibrium are not in accord with the expected cloud point temperature. The cloud point curve represents a phase separation process occurring in local regions (space limited to μm) and in time scale of the order of minute, while the process Va(t) occurred in the whole space of the concentrated phase, in time scale of days. For quantitative characterization of the network present in the concentrated phase, a precise value of the polymer-solvent interaction parameter x is needed.

种子溶胀悬浮聚合法制备分子印迹聚合物微球

以酪氨酸为印迹分子 ,甲基丙烯酸为功能单体 ,三羟甲基丙烷三甲基丙烯酸酯 (TRIM )为交联剂 ,采用种子溶胀悬浮聚合法在水溶液中制备了一系列分子印迹聚合物微球 (MIPMs)。利用扫描电镜 (SEM)对此微球的粒径大小、粒径分布、表面孔与孔径分布等进行了分析研究 ,探讨了影响其形貌的主要因素 ,并将所得微球用作色谱固定相研究了其分子选择吸附性能。研究表明 ,种子溶胀悬浮聚合法能够制得单分散性较好的、表面带有微孔的分子印迹聚合物微球 ,且该微球呈现出较好的特异吸附性能。

多孔聚合物微球的制备及其在化妆品中的应用进展

简要介绍了单分散多孔聚合物微球的应用,重点综述了多孔聚合物微球用作化妆品活性物载体时所起的控释和缓释作用;讨论了多孔聚合物微球的合成手段,包括悬浮聚合法、分散聚合法和种子溶胀法,种子溶胀法中的动态溶胀法和二步溶胀法更易得到粒径均一的多孔聚合物微球;同时介绍了其成孔机理和性能表征;最后提出了多孔聚合物合成以及在化妆品应用中目前存在的问题、发展方向和应用前景。

pH敏感性和温敏性聚丙烯酸钠与聚N-异丙基丙烯酰胺互穿网络材料的合成及其溶胀行为的研究

制备了对温度和pH值具有双重敏感性的PAANa/PNIPAM互穿网络(IPN)材料,测定了IPN的平衡溶胀度和在不同温度和pH中的溶胀度变化的行为。结果显示,这种材料能分别在32℃和pH为5.5发生溶胀行为的突变, 溶胀度突变范围明显高于以往文献所报道的类似材料的变化值。根据它在温度变化和pH值变化中的溶胀行为可以得知,在网络中这两种分子链是独立作用的,但是相互之间又有影响。

壳聚糖接枝聚丙烯酸高吸水性树脂的合成工艺

在水溶性引发剂过硫酸铵的引发下,使丙烯酸在壳聚糖的分子链上接枝聚合,并加入N,N′-亚甲基双丙烯酰胺进行一定程度的交联,制得高吸水性树脂。采用FT-IR和SEM对所合成的高吸水性树脂进行了结构表征。研究了反应条件对所制得的高吸水树脂吸水性能的影响。结果表明,使树脂具有最高吸水性能的最优化反应条件为:m(AA)/m(CTS)=10,引发剂和交联剂与单体的质量比分别为3.3%和0.16%,反应温度65℃,反应时间5.5 h。在此条件下合成的树脂最大吸水倍率可达1180 g/g,吸盐水倍率可达120 g/g。

二元共聚高吸水性树脂的合成与溶涨性能

以N ,N′ -亚甲基双丙烯酰胺为交联剂 ,过硫酸钾为引发剂 ,采用溶液聚合法合成了丙烯酸 -丙烯酰胺二元共聚高吸水性树脂 .研究了单体组成、单体浓度、引发剂用量、交联剂用量、反应温度等因素对产物性能的影响 .

改性玉米秸秆制备农用保水剂及其性能研究

以改性玉米秸秆(MPCS)、丙烯酸单体(AA)为接枝共聚原料,以N,N′-亚甲基双丙烯酰胺(MBA)为交联剂,过硫酸铵(APS)为引发剂,合成新型农用保水剂,并对保水剂吸水性能影响因素进行分析:当固定单体丙烯酸用量为100 g时,改性玉米秸秆最佳用量为10 g,引发剂用量为1.2 g,交联剂为0.15 g,反应温度为70℃,丙烯酸中和度为90%。所得保水剂胶体最大吸水倍率在蒸馏水和0.9%生理盐水中吸液量分别为823 g/g和83 g/g。红外光谱分析和电镜扫描表明,保水剂胶体接枝聚合成功,胶体具有良好的表面形态。

NVP接枝壳聚糖水凝胶的合成与溶胀性能

合成了N乙烯基吡咯烷酮(NVP)接枝壳聚糖(CHI)水凝胶,讨论了NVP/CHI、引发剂、交联剂、聚合温度、乙酸浓度等因素对接枝率及凝胶溶胀性能的影响,NVP∶CHI为6时,接枝率达到300%以上.溶胀温度、pH值、盐浓度等对凝胶溶胀性能的影响实验表明,凝胶表现出温度敏感性,在40℃出现最大平衡溶胀率,并观察到一级相转变;在中性或弱酸性介质中溶胀性能较好;与PVP凝胶相比,NVP接枝CHI凝胶表现出反聚电解质效应.溶胀动力学研究表明,在溶胀前期,CHI含量较高时,凝胶趋向于非Fick溶胀,说明除了溶剂扩散外,凝胶网络链段弛豫、水分子与凝胶网络间及凝胶高分子链段间相互作用对凝胶溶胀性能的影响至关重要;CHI含量较高时则趋向于Fick溶胀.

利用^(60)Coγ辐射聚合技术研制淀粉型农用高吸水材料

利用60Co g 辐射聚合技术合成淀粉接枝丙烯酸盐高吸水材料。辐照剂量7 kGy左右、交联剂用量0.01墶?墶⑺芤旱膒H值为5—8、淀粉用量在10%—30%时制成吸水倍率可达600倍、性价比较高的农用高吸水材料。