Cationic starch derivatives as reactive shale inhibitors for water‐based drilling fluids

One of the major problems associated with the use of water‐based drilling fluids is the interaction of water with specific rock formations, such as shales, and the consequent swelling of reactive clays that may be present in that type of rock. Several types of clays reactivity inhibitors have been used by the oil industry, and the most effective ones are the cationic polyelectrolytes, such as the poly(diallyldimethylammonium chloride) (PDADMAC). However, this polyelectrolyte is very toxic. In this work, a series of cationic starch derivatives with different cationic degrees were synthesized with the objective of evaluating their potential as environmentally correct shale reactivity inhibitors. The results showed that the synthesized derivatives presented a good capacity of adsorption on bentonite and an efficient inhibition of the shale reactivity. The derivative with an intermediate cationic degree presented the best performance. In the tests with the formulated fluids this derivative provided an intact cuttings recovery of 84.8% and a total recovery of 92.3%. These values are very close to those found for the PDADMAC additive, therefore indicating that this cationic starch derivative presents a good potential as inhibitor of the shale reactivity. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46621.     

The structure and application of amine‐terminated hyperbranched polymer shale inhibitor for water‐based drilling fluid

Amine‐terminated hyperbranched polymer (HBP‐NH₂), as an inhibitor in water‐based drilling fluid, is prepared by the polycondensation of diamine AB₂ monomers. The primary amine and secondary amide structures are confirmed by Fourier transform infrared spectroscopy and nuclear magnetic resonance hydrogen spectroscopy. Through time of flight mass spectrometry, the molecular weight of HBP‐NH₂ is mainly distributed in the range of 200–1400. Also, the quasi‐spherical shape and the high temperature resistance (200 °C) performance of HBP‐NH₂ are, respectively, certified through the environmental scanning electron microscope and the thermogravimetric analysis. In the inhibition performance test, the linear expansion rate of sodium bentonite in 3 wt % HBP‐NH₂ aqueous solution is only 11.42%, which is lower than other inhibitors (KCl, FA‐367, and HPAM). Zeta potential analysis shows that HBP‐NH₂ has a strong ability to inhibit the hydration and dispersion of sodium bentonite by protonated primary amine groups. Compared with the base slurry, the absolute value of zeta potential is reduced by 25.5 mV in the slurry containing 3 wt % HBP‐NH₂ at 180 rpm. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45466.     

Synthesis of an amphoteric polymer as a high-temperature-resistant shale stabilizer in water-based drilling fluids

To meet the increasing requirement of stabilizing shale under high-temperature situation with the use of water-based drilling fluids (WBDFs), the high-performance shale stabilizer is an urgent need. In this study, an amphoteric copolymer of AM/DMDAAC/NVP (APC) was synthesized by acrylamide (AM), dimethyl diallyl ammonium chloride (DMDAAC), and N-vinylpyrrolidone (NVP) and used as a high temperature-resistant shale stabilizer. The Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy confirmed the successful synthesis of APC. The inhibitive performance of APC was systematically evaluated and compared with three other commonly used shale stabilizers, including the anionic potassium polyacrylamide (KPAM), cationic poly dimethyl diallyl ammonium chloride (PD), and amphoteric polymer FA367. The results demonstrated that APC displayed excellent performance on the linear swelling test, hot-rolling recovery experiment, and shale immersion test. Furthermore, APC combined the advantages of high shale recovery percentages of PD and maintaining shale pellet integrity of KPAM, avoiding the drawbacks of enormous filtration volume of PD and low shale recovery percentages of KPAM. These great properties indicated that APC would be suitable as a shale stabilizer in WBDF to drill high-temperature shale formation.     

β‐Cyclodextrin modified cationic acrylamide polymers for flocculating waste drilling fluids

In this article, the P(AM/A‐β‐CD/DMDAAC) is used as flocculant. The synthesis and characterization of the cationic polyacrylamide flocculant modified by β‐cyclodextrin have been studied in the early article. This article stresses its excellent flocculated performance and mechanism. In the flocculated process, the bridging flocculation played a dominant role. Through the flocculation experiments, it can be seen that the flocculating rate of the P(AM/A‐β‐CD/DMDAAC) on four solutions can go up to 93.4%, 89.7%, 85.1%, and 96.7%, respectively. As can be seen from experiment data, the flocculated property of P(AM/A‐β‐CD/DMDAAC) is superior to polyacrylamide and poly (dimethyl diallyl ammonium chloride). © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40197.     

Influence of glycerides–xanthan gum synergy on their performance as lubricants for water‐based drilling fluids

Water‐based fluids for drilling wells are an environmentally friendly alternative to oil‐based formulations typically used in the oil industry. Aqueous mixtures of nonionic monoglyceride surfactants (C6, C8, C10, C12, and C18 carbon chains) and xanthan gum (XG) were investigated with that purpose, correlating their lubricity and solubility in water, as well as using surface tension and contact angle measurements. The results showed that monoglycerides behave as excellent lubricants in water, with a steady decrease of the friction coefficient as the hydrocarbon chain length increased. Monoglycerides were able to reduce the friction coefficient even further when used in XG suspensions, suggesting that they are probably forming a complex with the polysaccharide that shows a synergy toward their performance as lubricants. Experiments of adsorption onto iron oxide nanoparticles also produced evidence of the interaction between these molecules, which favors their adsorption on the metal surface. These results indicate that interactions occurring in solution between the surfactants and the polysaccharide are crucial in the mechanism of action of these mixtures as lubricants in water‐based drilling fluids. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41085.     

Structure–property relationship of polyetheramines as clay‐swelling inhibitors in water‐based drilling fluids

The influences of structure parameters of polyetheramines as clay‐swelling inhibitors in water‐based drilling fluids on the application performances were studied. Interactions of polyetheramines with clays were investigated through elemental analysis (EA), X‐ray diffraction (XRD), and thermogravimetric analysis (TGA). The results showed that lower molecular weight, hydrophobic oxypropylene segment, and plentiful amino group of polyetheramines favored improvement of inhibitive properties, enhancement of adsorption abilities, and expelling interlayer bound waters of clays (as confirmed by cutting rolling test, bentonite inhibition test, EA, XRD, and TGA studies). Simultaneously, the polyetheramines did not produce adverse effect to filtration control of the drilling fluids. In addition, XRD patterns revealed that these polyetheramines could intercalate into interlayer spaces of clays and display a monolayer arrangement. The corresponding basal spacing of clays was correlated only with molecular weight of polyetheramines. The dense loading of polyetheramines in the interlayer of clays was beneficial in improving inhibitive properties. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Supermolecular structure and mechanical properties of P(AN-AM-AA)/PVA intermacromolecular complex formed through hydrogen bonding

In this article the supermolecular structure and mechanical properties of poly(acrylonitrile-acrylamide-acrylic acid)/poly(vinyl alcohol) [P(AN-AM-AA)/PVA] intermacromolecular complex formed through hydrogen bonding were studied by means of SEM, TEM, and mechanical property testing. The experimental results show that fibrous or network structure could be formed in P(AN-AM-AA)/PVA intermacromolecular complex, and this unique supramolecular structure endows the material with much superior mechanical properties to its constituents. The tensile strength of P(AN-AM-AA)/PVA complex is as high as 3 times that of PVA, and the Young's modulus of the complex is almost 6 times that of PVA. All the encouraging results demonstrate that intermacromolecular complexation among the polymers having complementary structures is an innovative strategy to reinforce polymer materials and, therefore, to prepare a new kind of microcomposites. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 2089–2096, 1997     

Hydrophobically modified poly(ethylene glycol) as reactive clays inhibitor additive in water‐based drilling fluids

Adsorption measurements and inhibition tests were used to investigate the mechanisms of shale stabilization by hydrophobically modified poly(ethylene glycol) (PEG). Commercially available PEG with a large range of molar masses and PEG diesters were adsorbed on smectite‐rich clay from saline solutions and the clay/polymer complexes obtained were characterized by thermogravimetric analysis and x‐ray diffraction. The adsorption isotherms obtained for all unmodified PEG showed low affinity for the clay surface, however they all accessed the interlamellar spaces of the clay and reduced the clay water content of the complexes obtained. The PEG macromolecules had their affinity for the clay strongly enhanced by the hydrophobic modification especially with dodecanoic acid and were intercalated into the clay matrix, reducing, in a more efficient way, the water uptake by the clay. Conventional rolling tests were performed to evaluate the effect of polymers on the clay cuttings integrity. Results show that under conditions promoting the adsorption of polymers on both external and interlayer clay surfaces, displacement of the water from the clay was obtained and dispersion and disintegration of clay cuttings were inhibited. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Comb‐shaped copolymer as filtrate loss reducer for water‐based drilling fluid

A new comb‐shaped copolymer was synthesized by free radical copolymerization of 2‐acrylamide‐2‐methyl propane sulfonic acid, acrylamide, N‐vinyl‐2‐pyrrolidone, and allyl polyoxyethylene ether (APEG) monomers. The copolymer was evaluated as a filtrate loss reducer in water‐based drilling fluid at 180 °C environment, and found to work well without causing high viscosity effect. Composition of the copolymer was determined by Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy, and gel permeation chromatography. FTIR, X‐ray diffraction,, and environmental scanning electron microscopy characterizations were used to probe the filtrate loss mechanism of the comb‐shaped copolymer. Thermogravimetry and differential scanning calorimetry results showed that thermal degradation of the copolymer is not obvious before 293.6 °C. The copolymer is found to be superior to its commercially available counterparts for controlling filtrate loss volume and maintaining a steady viscosity after 180 °C aging. Higher content of APEG in the copolymer helps maintain rheological properties of the drilling fluid after aging and reduces filtrate loss volume. The morphology of the copolymer in aqueous solution displays a comb‐shaped 3D structure and shows clear adsorption onto clay particles. The working mechanism for copolymer is that anchoring groups bind the copolymer onto clay particles through different binding mechanisms, while colloidal suspension stability is achieved by steric hindrance and electrostatic repulsion, as well as through PEG segment intercalation into clay lamellae. The copolymer is able to cover and seal the micro‐holes in the mud cake even at high temperature to reduce permeability. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45989.     

Poly (diallyldimethylammoniumchloride)/sodium‐montmorillonite composite; structure,and adsorption properties

A cationic polyelectrolyte, poly (diallyldimethylammoniumchloride) (PDADMAC) and a smectite‐type layered silicate (sodium activated montmorillonite clay (Sodium‐Montmorillonite, NaMt)), intercalated composites (PDADMAC/NaMt) were prepared. Basal spacings (d001) of NaMt in composites were measured by X‐Ray diffraction analysis (XRD). Ultrasonic addition of low molecular weight PDADMAC into the NaMt structure (at very low concentration and very low PDADMAC(g)/NaMt(g) ratios) resulted in good adsorbing properties both for positively and negatively charged dyes. The adsorption kinetics of the prepared composites both for negatively charged [remazol black (RB)] and positively charged [methylene blue (MB)] reactive dyes were investigated. The RB adsorption efficiency of the positively charged composite is approximately three times that of the pure NaMt while its MB adsorption efficiency is as good as that of pure NaMt. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Cationic and hydrophobically modified chitosans as additives for water‐based drilling fluids

Water‐soluble chitosan derivatives are synthesized via a two‐step procedure that includes the hydrophobization of chitosan using different acyl chlorides, and then the alkylation of some of the amine groups. Rheology, conventional rolling, and filtration tests are performed to evaluate the effect of the modified polysaccharides on the rheological behavior of the fluid, as well as on the clays cuttings integrity and on the control of fluid loss for the geological formations. The results indicate that the product with C16 segments, 2% (wt/vol) concentration and high molar weight led to aqueous solutions with a pseudoplastic behavior equivalent to the one presented by the commercial rheology modifier used in water‐based drilling fluids. In addition, the hydrophobically modified cationic chitosan shows an excellent capacity for inhibiting the clays reactivity and for keeping the cuttings integrity. The results also show that this product can significantly decrease the volume of filtrate, leading to values comparable to the ones obtained with commercial additives, and therefore suggesting that it could be considered to replace some of the drilling fluid additives commonly used. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40300.     

Hyperbranched polyglycerols,obtained from environmentally benign monomer,as reactive clays inhibitors for water‐based drilling fluids

To prevent the degradation of the borehole and also the disintegration and dispersion of drilled cuttings, different shale stabilizing additives are used in water‐based drilling fluids (WBFs). Glycols, poly(ethylene glycol), glycerols, and polyglycerol derivatives, also called polyols, have been used to inhibit shales containing reactive clays in WBF. These additives are normally used in conjunction with KCl to reduce clay swelling and dispersion of drilled cuttings. Highly branched polymers have become an important field in current polymer science. Such materials typically exhibit compact, globular structures in combination with an exceptionally high number of sites with functional groups. They have unique properties that differ significantly from their linear counterparts, and the hyperbranched polyglycerol (hPG) is an important hyperbranched polymer that can be produced from an environmentally benign monomer, the glycerol carbonate. In this article, the clay inhibitive properties of hPG were evaluated by different test methods including bentonite inhibition test, cuttings recovery, and X‐ray diffraction measurements. The results show that the hPG has a great potential to be used as an environmental friendly inhibitor additive in WBFs. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40384.     

Poly(ethylene terephthalate)/poly(ethylene glycol‐co‐1,3/1,4‐cyclohexanedimethanol terephthalate)/clay nanocomposites: Effects of biaxial stretching

In this study, we fabricated poly(ethylene terephthalate) (PET)/clay, PET/poly(ethylene glycol‐co‐1,3/1,4‐cyclohexanedimethanol terephthalate) (PETG), and PET/PETG/clay nanocomposite plates and biaxially stretched them into films by using a biaxial film stretching machine. The tensile properties, cold crystallization behavior, optical properties, and gas and water vapor barrier properties of the resulting films were estimated. The biaxial stretching process improved the dispersion of clay platelets in both the PETG and PET/PETG matrices, increased the aspect ratio of the platelets, and made the platelets more oriented. Thus, the tensile, optical, and gas‐barrier properties of the composite films were greatly enhanced. Moreover, strain‐induced crystallization occurred in the PET/PETG blend and in the amorphous PETG matrix. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42207.     

Re‐entrant transition of aluminum‐crosslinked partially hydrolyzed polyacrylamide in a high salinity solvent by rheology and NMR

Linked polymer solution (LPS) is a nanoparticle polymer and designed by crosslinking a high molecular weight partially hydrolyzed polyacrylamide (HPAM) with aluminum (III). It has been applied in the oil industry to enhance oil recovery by improving sweep efficiency and by microscopic diversion in porous media. To achieve good propagation properties, aggregates formed by intermolecular crosslinking and gel formation should be avoided. To our knowledge, there is no established method to distinguish between intra‐ and intermolecular crosslinking for high molecular weight (>10 × 10⁶ Da), low concentration (<1000 ppm), polydisperse solutions of partially hydrolyzed polyacrylamides in high salinity solvents (5 wt % NaCl). The high salinity solvent is relevant to represent for formation water in many oil reservoirs. The main objective of the present study is to establish an experimental method for determining phase transition of LPS from monomeric coiled state to aggregated state in a high salinity solvent. No single experimental methods are conclusive and we have therefore applied a combinatorics approach including two‐dimensional NMR, dynamic rheology, and UV spectroscopy. The different techniques show similar trends, which allow overall interpretations of phase transitions to be made. The experimental results indicated that the LPS solution at high salinity solvent underwent a phase transition by chain re‐expansion, called reentrant transition. The transition point was observed at addition of 100 ppm of Al³⁺. Higher concentrations of Al³⁺ suppressed the rate of reentrant transition, most likely because of intramolecular crosslinking of HPAM chains by Al³⁺. Intermolecular crosslinking reaction was not observed at these conditions. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43825.     

Semidry synthesis of the poly(acrylic acid)/palygorskite superabsorbent with high‐percentage clay via a freeze–thaw–extrusion process

A problem with the synthesis of polymer/clay composites is the poor compatibility between clay and polymers; this is particularly bad for those with a high percentage of clay. In response, we introduced a freeze–thaw–extrusion process before polymerization to make the best use of the high activation ability of acrylic acid (the monomer) and the exceptional hydration of palygorskite (clay). This processing was powerful for facilitating clay dispersed into the nanoscale and for obtaining good compatibility with the polymer, even for those polymers with high clay contents. The experiment showed that the quality of the consequent superabsorbent was improved significantly. As the dispersion was worked out perfectly by the freeze–thaw–extrusion process, we further explored the effect of the system water content on the water absorptivity of the consequent composite. With synthesis by the improved system, the water absorbency still amounted to 98.2 g/g in a 0.9 wt % NaCl solution for the composite with 35 wt % clay, whereas the water content (55 wt %) was much less than that of general synthesis (ca. 95 wt %). Scanning electron microscopy showed that the composite had a rich pore structure in the range of several hundred nanometers, and the palygorskite was distributed perfectly in the composite on the nanoscale. Fourier transform infrared spectroscopy gave further direct evidence for the reaction between the clay and polymer. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Biopolyester‐based nanocomposites: Structural,thermo‐mechanical and biocompatibility characteristics of poly(3‐hydroxybutyrate)/montmorillonite clay nanohybrids

In this work, the structural, thermal, mechanical, and biocompatibility characteristics of biopolyester‐based nanocomposites with phyllosilicate clays, namely those of poly(3‐hydroxybutyrate) (PHB) with octadecylamine‐modified montmorillonite (C₁₈MMT), are reported. PHB/clay nanocomposites with various loadings were prepared by melt mixing. X‐ray diffraction measurements and transmission electron microscopy images revealed the coexistence of intercalated and exfoliated states in the produced nanocomposites. Atomic force microscopy imaging also shed light to the morphological characteristics of the pure PHB and the prepared nanocomposites. The thermal stability of the nanohybrid materials was improved with the 5 wt % loading nanocomposite to show the best improvement. In addition, the nanohybrids have lower melting point compared to pure PHB and enhanced storage modulus (E′). Finally, the biocompatibility of pristine PHB and the 5 wt % nanocomposite was assessed by studying the morphology and proliferation of osteoblast cells attached on their surfaces. The results after 3 and 7 days of cell culturing indicate the incorporation of nanoclays does not change the cell adhesion and spreading as compared to those on pure PHB. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41628.     

Preparation of heat resisting poly(methyl methacrylate)/graphite composite microspheres used as ultra‐lightweight proppants

Ultra‐lightweight heat resisting poly(methyl methacrylate) (PMMA)/graphite microspheres were successfully prepared via in situ suspension polymerization. The Fourier transform infrared and X‐ray powder diffraction results confirmed the successful preparation of the composite microspheres. Field emission scanning electron microscope analysis illustrated that the graphite particles were dispersed in microspheres and the PMMA/graphite composite microspheres had good sphericity and roundness. Furthermore, density analysis indicated that the apparent density of composites microspheres was about 1.055–1.135g/cm³ which was suitable for the transmission with water carrying. The results from thermodynamic test revealed that the thermal stability of the composite was significantly improved with increasing graphite content, which could be used as ultra‐lightweight proppant in deep underground. In addition, the crushing rate decreased to 0.5% with graphite ratio of 3.0% at the pressure of 69 MPa. Therefore, PMMA/Graphite composite microspheres exhibit a promising application in petroleum or gas exploitation as water carrying fracturing proppants. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41924.     

ANN modeling in Pb(II) removal from water by clay‐polymer composites fabricated via the melt‐blending

This work presents two new related aspects in heavy‐metal adsorption. The first aspect is the use of Cloisite^® C20A‐polycaprolactone (C20A‐PCL) composite with the aid of dry Na2SO4 in Pb(II) extraction from water. The composite was fabricated by means of the melt‐blending method at a filler loading rate of 3% (w/w). This material was able to remove 87% of Pb(II) from water despite the fact that the polymer is a thermoplastic and the C20A is hydrophobic. The second aspect is the modeling of the adsorption data obtained using polymer‐clay composites synthesized via the melt‐blending method by artificial neural networks. A network with 10 neurons and using TRAINLM, and employing tansig function in the input layer and purelin in the output layer was found to be optimal. The network was used to predict the adsorption efficiency of Pb(II) by several clay‐polymer composites and the correlation was satisfactory. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3894–3901, 2013     

Nanocomposite piezoelectric films of P(VDF‐TrFE)/LiNbO3

Piezoelectric films were prepared by incorporation of lithium niobate (LiNbO₃) nanoparticles into copolymer of vinylidene difluoride and trifluoroethylene. Nanoparticles of LiNbO₃ with ferroelectric phase were successfully synthesized and dispersed homogenously by ultrasonication in the copolymer matrix without any surfactant or surface functionalization. The nanocomposites were fully characterized by electronic microscopy, X‐ray diffraction, differential scanning calorimetry, dynamical mechanical analysis, and piezometer. Surprisingly, the copolymer matrix crystallinity and morphology were not affected by the incorporation of nanoparticles. Therefore the nanocomposites remained good mechanicals properties and high ferroelectricity coupled to nonlinear optical activity thanks to the noncentro symmetric space group of lithium niobate. This could be a novel approach to develop new multifunctional materials. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Modified zeolitic–midazolate framework 8/poly(ether‐block‐amide) mixed‐matrix membrane for propylene and propane separation

In this study, we fabricated a dual‐layer PES–poly(ether‐block‐amide) (PEBA) composite membrane that included zeolitic–midazolate framework 8 (ZIF‐8) particles and evaluated it for propylene and propane separation under pure and mixed feed conditions. To improve the performance, compatibility, and distribution of particles in the polymer matrix, the ZIF‐8 particles were modified by 3‐(triethoxysilyl) propyl amine (APTES) and 3‐(trimethoxysilyl) propyl amine (APTMS) amino silane coupling agents. Particle modification did not have much effect on the structure and particle size and slightly reduced the membrane specific surface area. The modified particles tended to be in the soft section. At the high loading rate of modified particles, their appropriate compatibility increased the membrane gas permeability () and selectivity. APTES with the proper chain length compared with APTMS had a higher and the same selectivity. The best performance (by 32.1 gpu) was found in PES–PEBA–ZIF‐8–APTES 20%. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46273.