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.     

Linear‐dendritic copolymers as nanocatalysts

Functionalized poly(ethylene glycol) (PEG) containing four chloride end functional groups (PEG‐Cl₄) was synthesized through reaction between cyanuric chloride and PEG‐(OH)₂. Chloride end functional groups of PEG‐Cl₄ were able to initiate the ring opening polymerization of 2‐ethyl‐2‐oxazoline and star copolymers containing a PEG core, and poly(2‐ethyl‐2‐oxazoline) (POX) arms were obtained. Polymerization was quenched using diethanolamine, and star copolymers containing hydroxyl end functional groups (PEG‐POX‐OH) were obtained. ε‐Caprolactone was then polymerized using the hydroxyl end functional groups of star copolymers and amphiphilic linear‐dendritic copolymers containing PEG and POX, and poly(caprolactone) (PCL) blocks were synthesized. Linear‐dendritic copolymers were able to load the organic and inorganic guest molecules. Application of host‐guest systems such as nanocatalyst for Heck chemical reaction was also investigated. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Flow improvement of Liaohe extraheavy oil with comb‐type copolymers

Liaohe extraheavy oil is a kind of special crude oil with high paraffin and asphaltene contents and a pour point of up to 60°C. To improve its flowability, comb‐type poly(maleic alkylamide‐co‐α‐octadecene) copolymers (MACs) with various amidation ratios were synthesized and used. Model oils containing paraffin mixtures with the same average carbon number to Liaohe extraheavy oil with and without asphaltene were prepared to explore the effect of the MACs on paraffin crystallization and asphaltene dispersion, respectively. We found that MACs reduced the yield stress, changed the size and shape of the paraffin crystals, and obstructed the paraffin crystallization for both model oils and extraheavy Liaohe oils as observed by rheology, polarizing light microscopy, X‐ray diffraction, and differential scanning calorimetry. The MACs seemed to be an ideal candidate for improving the flowability of Liaohe extraheavy oils. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40082.     

Conduction mechanism in H‐type polysiloxane‐polypyrrole block copolymers

Conducting polymers of polysiloxane‐polypyrrole were synthesized by electropolymerization of the pyrrole monomer through pyrrole moieties in N‐pyrrole‐terminated polysiloxanes. Sodium paratoluene sulfonate was used as the electrolyte. Scanning electron microscopy (SEM) was used to determine the surface morphology of the films. The room‐temperature conductivity values of the films were found to be in the range of 1.9–4.4 × 10^?4 (Ω cm)^?1, depending on the supporting electrolyte concentration. The temperature dependence of the dc conductivities of the copolymers having different dopant concentrations was investigated within the temperature range of 100–320 K. The evaluated parameters showed that the electrical transport is dominated by variable range hopping. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 52–56, 2002     

Synthesis and investigation of properties of silaoxadihydrophenanthrene‐diphenylsiloxane fragments containing block copolymers

The reaction of heterofunctional condensation of 1,1‐dichloro‐1‐sila‐2‐oxadihydrophenanthrene with dihydroxydiphenylsilane at various ratios of initial compounds in the presence of pyridine is investigated. α,ω‐Dihydroxysilaoxadihydrophenanthrene‐diphenylsiloxane oligomers with various degrees of condensation are obtained. Organosiloxane block copolymers with the regular arrangement of silaoxadihydrophenanthrene‐diphenylsiloxanes fragments in the main linear dimethylsiloxane chain are produced by the reaction of heterofunctional condensation of α,ω‐dihydroxysilaoxadihydrophenanthrene‐diphenylsiloxanes with α,ω‐dichlorodimethylsiloxanes in the presence of anhydrous pyridine, as an acceptor of hydrochloric acid. Thermogravimetry, differential scanning calorimetry, gel permeation chromatography, and wide‐angle X‐ray analysis are carried out on the synthesized block copolymers. The microheterogeneous structure of block copolymers is observed at definite values of the length of the flexible dimethylsiloxane chain by DSC and X‐ray investigation. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 9–16, 2002; DOI 10.1002/app.10045     

Linear‐dendritic ABA triblock copolymers as nanocarriers

Linear‐dendritic ABA triblock copolymers containing PEG were used for transport the small guest molecules such as 5,7‐dibromo‐8‐hydoxy quinoline, ibuprofen, and Congo red. Nanocarriers containing guest molecules were soluble in water and in some of the organic solvents. Encapsulated guest molecules were soluble in some of the solvents, which they cannot be solved in them solely, for example, chloroform is a very poor solvent for Congo red, but encapsulated Congo red by nanocarriers is soluble in chloroform. The linear‐dendritic copolymers/guest molecule complexes were stable at room temperature for about 10 months; during this time, guest molecules did not release from linear‐dendritic copolymers/guest molecule complexes. The controlled release of guest molecules from linear‐dendritic copolymers/guest molecule complexes in vitro conditions also was investigated. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 267–272, 2007     

Polydimethylsiloxane macromonomer bearing N‐vinylcaprolactam as end group: thermosensitive graft copolymers via free radical polymerization

A polydimethylsiloxane macromonomer was synthesized via anionic ring‐opening polymerization of hexamethylcyclotrisiloxane using N‐vinylcaprolactam anion as initiator and trimethylsilyl chloride as terminating agent. The polydimethylsiloxane macromonomer was copolymerized with N‐vinylcaprolactam in different molar ratios via a free radical mechanism. The new class of graft copolymers thus obtained shows cloud points in water because of an excess of N‐vinylcaprolactam units in the polymer chain. These cloud points can be shifted using randomly methylated β‐cyclodextrin as complexing agent. © 2015 Society of Chemical Industry     

Synthesis and characterization of novel copolymers with the trimethylsilyl group for deep‐UV photoresists

N‐(4‐Acetoxyphenyl) maleimide (APMI) and three kinds of comonomers bearing a trimethylsilyl group were copolymerized at 60°C in the presence of azobisisobutyronitrile (AIBN) as an initiator in 1,4‐dioxane to obtain the three IP, IIP, and IIIP copolymers. These copolymers were removed from the acetoxy group in a transesterification process into new IVP, VP, and VIP copolymers with a pendant hydroxyl group. Two modified processes were adopted to prepare photoresists using these copolymers. The first process involved mixing the dissolution inhibitor, o‐nitrobenzyl cholate, with the new copolymers. Second, o‐nitrobenzyl cholate was introduced into the copolymers using 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) in dimethylformamide (DMF). The cyclic maleimide structure is responsible for the high thermal stability of these copolymers. After irradiation using deep–UV light and development with aqueous Na₂CO₃ (0.01 wt %), the developed patterns showed positive images and exhibited good adhesion to the silicon wafer without using any adhesion promoter. The resolution of these resists was at least 0.8 μm and an oxygen‐plasma etching rate was 1/5.3 to that of hard‐baked HPR‐204. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2791–2798, 2002; DOI 10.1002/app.10255     

Mechanical properties of conducting H‐type polysiloxane–polypyrrole graft copolymers and polytetrahydrofuran–polypyrrole block copolymers

The mechanical properties of block copolymers of polypyrrole and pyrrolyl‐ended azobis‐polytetrahydrofuran (TPPy) and graft copolymers of pyrrolyl‐ended H‐type polydimethylsiloxane (SPPy) were investigated and compared with those of polypyrrole (PPy). Conducting films were prepared electrochemically at a constant potential and doped with p‐toluene sulfonate. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1663–1666, 2002     

Cassava starch‐graft‐polymethacrylamide copolymers as flocculants and textile sizing agents

Cassava starch‐graft‐polymethacrylamide (PMAM) copolymers were synthesized by a free‐radical‐initiated polymerization reaction, and the products were tested for their efficiency as flocculants and textile sizing agents. The highest percentages of grafting and monomer conversion were 79.9 and 78.0%, respectively. The grafted starches were characterized by Fourier transform infrared spectroscopy, X‐ray diffraction analysis, scanning electron microscopy, differential scanning calorimetry, and thermogravimetric analysis. The average molecular weight of PMAM chains in the grafted starches ranged from 15.9 to 30.8 × 10⁵ g/mol. The grafted starches exhibited a higher peak viscosity and paste stability in comparison to the native starch (NS). Dynamic mechanical analysis showed that grafting provided fairly shear‐stable hydrogels, and the highest storage modulus obtained was 17,900 Pa compared to 1879 Pa for NS. The flocculation studies demonstrated the superiority of starch‐g‐PMAM over cassava starch and PMAM as an efficient flocculant. The tensile strength of cotton yarns sized with the starch‐grafted copolymer was significantly higher (104 MPa) compared to that sized with NS (34 MPa). © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39810.     

Comb‐like polymer‐graphene nanocomposites with improved adhesion properties via surface‐initiated atom transfer radical polymerization (SI‐ATRP)

The synthesis and properties of comb‐like polymer‐graphene nanocomposites via surface initiated atom transfer radical polymerization is reported. The crystallization temperature (T_c) and melt temperature (T_m) of the comb‐like homopolymer increases from −18 to −8 °C and 1 to 11 °C, respectively, in the nanocomposite synthesized with 0.6 wt % graphene initiator. The rheological properties like modulus and complex viscosity of the nanocomposite show a twofold increase. Transmission electron microscopy results of the nanocomposite show a well‐intercalated structure with nanoscale distribution of graphene domains and in scanning electron microscopy a sheet‐like structure with corrugations, and crumples are seen. The hydrophobicity, as measured by water contact angle, increases from 101° in the homopolymer to 118° in the nanocomposite. The nanocomposites exhibit substantial increase in adhesive strength on different substrates, with peel strength increasing by more than 1000 times, as compared to the homopolymer. The improved tack and adhesion properties of the nanocomposites suggest them as novel materials for adhesive applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45885.     

Photoelectric properties of ABA‐type triblock copolymers designed using fluorine‐containing polyimide macroinitiators with polyhedral oligomeric silsesquioxane

4,4′‐(Hexafluoro‐isopropylidene) diphthalic anhydride‐2,3,5,6‐tetramethyl‐1,4‐phenylenediamine (6FDA‐TeMPD) was synthesized and reacted with polyhedral oligomeric silsesquioxane (POSS) to form an ABA‐type triblock copolymer by atom transfer radical polymerization. The solid‐state and optical properties of the resulting copolymers were systematically investigated, and their electronic states were analyzed. As the POSS concentration increased, the transparency across the entire wavelength range increased. In the ABA‐type triblock copolymers, a new transition was observed between the highest occupied molecular orbital in POSS and the lowest unoccupied molecular orbital in 6FDA‐TeMPD because of their high molecular size dispersion. Since the refractive index of 6FDA‐TeMPD decreased linearly as the POSS concentration increased, the refractive index of the ABA‐type triblock copolymers of 6FDA‐TeMPD with POSS could be easily controlled. POLYM. ENG. SCI., 57:1207–1213, 2017. © 2017 Society of Plastics Engineers     

Improvement of oil flowability by assembly of comb‐type copolymers with paraffin and asphaltene

Comb‐type (maleic acid alkylamides‐co‐α‐octadecene) copolymers (MACs) assemble with long‐chain n‐paraffins and asphaltenes by the hydrophobic alkyl branches and polar groups, respectively, and improve flowability of crude oils upon cooling. Their effects on the crystallization of paraffins from model oils were studied by rheology, optical microscopy, differential scanning calorimetry, and X‐ray diffraction. Upon cooling, MACs change the size and shape of paraffin crystals and reduce the yield stresses of gels generated by precipitated solids. Deposition of wax was significantly suppressed by MAC as observed using a laboratory‐scale deposition apparatus. MACs are more effective than poly(ethylene‐butene) copolymers in improving the flowability of crude oils containing asphaltenes. The interactions between the carboxyl and amide groups of MAC with the polar aromatic asphaltenes appear to stabilize crudes through the steric effects of the long alkyl groups of MAC polymers, thereby reducing the strength of paraffin/asphaltene gels formed on cooling. © 2011 American Institute of Chemical Engineers AIChE J, 2012     

Synthesis and characterization of negative‐type polyamic acid ester with 1‐methacryloyloxy‐2‐propanoate group

A negative‐type photosensitive polyamic acid (PAA) was synthesized from cyclobutane‐1,2,3,4‐tetracarboxylic dianhydride and 2‐(methacryloyloxy)ethyl 3,5‐diaminobenzoate in N‐methyl‐2‐pyrrolidinone. Glycidyl methacrylate was added into the PAA solution to yield a photosensitive PAA ester (PAE) by the ring‐opening esterification reaction of the carboxylic acid group in the PAA and glycidyl methacrylate. Esterification reactions were conducted with varying reaction temperatures and times. The typical PAE (PAE‐C3) with a degree of esterification of 20% was used for a photosensitivity study. We investigated the effects of the postexposure baking temperature, amount of photoinitiator, and exposure dose on the photosensitivity of PAE‐C3. Furthermore, a photolithography evaluation was conducted on PAE‐C3 in the presence of 1‐[4‐(phenylthio)phenyl]‐2‐(O‐benzoyloxime)‐1,2‐octanedione as a photoinitiator using a mercury lamp at a 365‐nm wavelength. The resolution of the film with 2.0‐μm thickness was about 8 μm. PAE‐C3 cured at 250°C for 60 min was stable up to around 310°C in a nitrogen atmosphere. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2252–2258, 2006     

Thermo‐ and pH‐ responsive copolymers: Poly(n‐Isopropylacrylamide‐co‐IAM) copolymers

Poly(N‐isopropylacrylamide) (NIPAAm) is well known as a smart material with good thermal sensitivity and favorable biocompatibility. A series of new smart hydrogels, NIPAAm copolymerized with IAM (itaconamic acid; 4‐amino‐2‐methylene‐4‐oxobutanoic acid), were synthesized through radical solution polymerization in this work. Poly(NIPAAm‐co‐IAM) can respond to the changes of temperature as well as pH value. Such a characteristic is due to the fact that IAM contains not only a hydrophilic acrylic acid moiety but also an acrylamide moiety to be thermal and pH sensitive. The experimental results show that the lower critical solution temperature (LCST) of the copolymer increases as the molar fraction of IAM increases. Moreover, based on the current experimental data, 3 wt % of Poly(NIPAAm‐co‐IAM) aqueous solution in this study exhibits a phase transition temperature (37.8°C) close to the human body temperature in the buffer solution of pH 7 possibly to be useful in drug delivery. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42367.     

Polar polystyrene‐isoprene‐styrene copolymers with long polybutadiene branches

Polar polystyrene‐isoprene‐styrene (SIS) copolymers having epoxide groups and long polybutadiene (PB) branches were synthesized via the combination of in situ epoxidation, anionic polymerization and graft‐onto reaction. They were characterized with ¹H NMR, GPC, FT‐IR, DSC, and contact angle test. Their polarity was determined by the epoxidation degree and graft efficiency. The epoxidation degree linearly increased with the epoxidation time. The graft efficiency decreased with the branch length, but increased with the epoxidation degrees. Although their glass transition temperature (T_g) of diene blocks and flexibility properties had been negatively affected by in situ epoxidation, they could be modulated by the epoxidation degree, branch length, and branch density. Their T_g could be tailored by the branch length and branch density since they fitted the Fox equation very well, especially as the longer branches were grafted. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40303.     

Synthesis and gas permeability of ABA‐type triblock copolymers derived from fluorine‐containing polyimide with polyhedral oligomeric silsesquioxane

ABA‐type triblock copolymers derived from 4,4'‐(hexafluoroisopropylidene)diphthalicanhydride‐2,3,5,6‐tetramethyl‐1,4‐phenylenediamine (6FDA‐TeMPD) and methacryl phenyl polyhedral oligomeric silsesquioxane (MPPOSS) were synthesized by atom transfer radical polymerization. The chemical structure of the synthesized ABA‐type triblock copolymer was confirmed by ¹H NMR, ¹³C NMR, ²⁹Si NMR and Fourier transform infrared analyses. The ratios of 6FDA‐TeMPD and MPPOSS determined by TGA were 94/6, 85/15, 77/23, 68/32, 57/43 and 31/69. The film density of the ABA‐type triblock copolymer films did not conform to the mixing rule because of polyimide (PI) chain aggregation. Based on contact angle and water uptake analyses, the hydrophobicity of the ABA‐type triblock copolymer film was determined to be higher than the theoretical value because of POSS cage effects and PI chain aggregation. The gas permeability coefficient of the ABA‐type triblock copolymer decreased compared with that of PI because of aggregation of PI chains and inhibition of solubility decreases by substitutes with high affinity. ABA‐type triblock copolymer CO₂/H₂ separation performance increased compared with that of PI. The ABA‐type triblock copolymer derived from PI and MPPOSS can be described as a polymer material with higher hydrophobicity and higher CO₂/H₂ selectivity than PI. © 2015 Society of Chemical Industry     

Cyclolinear organosilicon copolymers with monocyclic fragments in the side chain

The reaction of heterofunctional condensation of organodichlorosiloxycyclotri(tetra, penta) siloxanes and organodichlorosililcarbocyclotrisiloxane with dihydroxydimethylsiloxanes in the presence of pyridine was investigated. It was shown that at small lengths of the linear dimethylsiloxane link (n ≤ 4) the reaction of heterofunctional condensation runs both intermoleculary with formation of polymers and intramoleculary with formation of bicyclo‐organosiloxanes. It was established that insertion of cyclic fragments in the side chain hinders the chain transfer reactions that proceed with release of the D‐type cycles during thermal depolymerization. The conformational and hydrodinamic properties of some polymethylsiloxane copolymers with cyclosiloxane fragments in the side chain have been studied. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 583–594, 1999     

Comb‐like polymer with sulfo groups and its dispersion and rheological properties in aqueous ceramic suspensions

Two types of new comb‐like polymers were formed as dispersants for aqueous ceramic suspensions with isoprenyloxy poly(ethylene glycol ether), acrylic acid, maleic anhydride as the main starting materials. During the synthesis, one comb‐like polymer introduced sodium methylallyl sulfonate (SMAS) into the reaction media, whereas the other did not. The chemical structure and molecular weight were characterized by Fourier transform infrared spectroscopy and gel permeation chromatography. The effects of the polymers on the dispersion, ζ potential and rheological properties of the kaolin suspensions are discussed in detail. The results indicate that SMAS facilitated chain transfer, controlled the effective charge density of the surface, and increased the electrostatic repulsion force. The kaolin suspensions displayed shear‐thinning behavior on the basis of the electrostatic and steric effects of the comb‐like polymers. The apparent viscosity decreased from 1088 to 258 mPa s with the assistance of the SMAS‐prepared comb‐like polymer as a dispersant. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44563.     

Synthesis of cassava starch‐g‐poly(methyl methacrylate) copolymers with benzoyl peroxide as an initiator

Graft copolymers of cassava starch and methyl methacrylate (MMA) were synthesized by free‐radical polymerization with benzoyl peroxide (BPO) as an initiator in an aqueous medium at 80°C. The formation of graft copolymers was confirmed by analysis of the obtained products with Fourier transform infrared spectroscopy and scanning electron microscopy. The effects of the amount of cassava starch, the amount of MMA monomer, the amount of BPO, and the reaction time on the grafting characteristics were studied. The optimum condition for grafting were obtained when 5 g of cassava starch, 5 g of MMA, 0.1 g of BPO, and a reaction time of 3 h were used. These condition provided a graft copolymer with 25.00% add‐on, 81.40% monomer conversion, 54.30% homopoly(methyl methacrylate) formed, 45.70% grafting efficiency, 37.20% grafting ratio, and 95.54% yield. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4083–4089, 2006