Synthesis,characterization, and performance evaluation of the AM/AMPS/DMDAAC/SSS quadripolymer as a fluid loss additive for water‐based drilling fluid

According to the molecular structure design requirements of the fluid loss additive resistant to high temperature, 2‐acrylamide‐2‐methyl propane sulfonic acid (AMPS), acrylamide (AM), dimethyl diallyl ammonium chloride (DMDAAC) and sodium styrene sulfonate (SSS) are selected as the structure monomers. Using ammonium persulfate as initiator, a new quadripolymer is synthesized through free radical aqueous solution polymerization. According to the minimum filtration loss of the fresh water‐based drilling fluid with 0.5 wt % quadripolymer, The synthesis conditions are optimized by orthogonal test: the mole ratio of AMPS/AM/DMDAAC/SSS is 5/7/2/1, the monomer concentration is 30 wt %, the initiator concentration is 0.8 wt %, the reaction temperature is 75°C and the pH is 10. The structure of the quadripolymer is characterized by Fourier transform infrared spectroscopy and nuclear magnetic resonance hydrogen spectroscopy. The results show that the quadripolymer contains all the designed functional groups. The thermal stability of the quadripolymer is tested by thermogravimetry, differential thermogravimetry, and differential scanning calorimetry. The results show that the thermal degradation of the quadripolymer is not obvious before 272.3°C. The rheological performance and filtration loss of the quadripolymer are evaluated. The results indicate that the filtration loss decreases with the increasing dosage of the quadripolymer before and after thermal aging test at 180°C for 16 h, and the filtration loss before the thermal aging test is smaller than that after the thermal aging test. The high temperature high pressure filtration loss (FL_(HTHP)) experiment results also show that the quadripolymer fluid loss additive has excellent temperature‐resistant performance. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41762.     

Application of a new family of organosilicon quadripolymer as a fluid loss additive for drilling fluid at high temperature

An organosilicon quadripolymer of acrylamide (AM), 2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid (AMPS), N‐vinylpyrrolidone (NVP) and a kind of organosilicon monomer was synthesized by solution free radical polymerization. The chemical structure of organosilicon quadripolymer was characterized by Fourier transform infrared (FTIR) spectroscopy, and molecular weight distribution was determinate by gel permeation chromatography (GPC) under the best optimum synthesis conditions, which were identified by orthogonal test according to filtrate volume of fresh water‐based drilling fluid. The colloidal properties of the organosilicon quadripolymer drilling fluid were investigated in various media such as fresh‐water, 4.0% salt‐water, and saturated brine based fluid. The results showed that the filtrate volume decreased with the increase of the organosilicon quadripolymer concentration before and after the thermal aging test at 180°C for 16 h, and the filtrate volume after the thermal aging test was larger than that before the thermal aging test, but was smaller than the base fluid. The colloidal properties and the filtrate volume could be controlled effectively at aging temperatures not exceeding 200°C. The organosilicon quadripolymer drilling fluid performance was better than corresponding terpolymer without organosilicon group and shows favorable inhibitive property and was an excellent fluid loss additive for drilling fluid resisting high temperature in deep wells. A possible mechanism is proposed to explain the improvement according to the comparative adsorption experiment. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Rheological and electrical properties of Egyptian bentonite as a drilling mud

The flow properties of Egyptian bentonite as a drilling mud were studied using anionic polyacrylamide as an additive (MW 1,000,000 g/mol). The rheological properties (plastic viscosity, yield point, thixotropy) of bentonite–polyacrylamide mud were investigated at different concentrations (5–20 mg/L). It was found that, as polyacrylamide concentration increases, rheological properties increase after 24‐h aging time and up to 40°C. By increasing temperature, rheological properties become nearly constant. Electrical properties (electrophoretic mobility and zeta potential) of Na bentonite/PAM mud were measured using zeta meter. The results showed that zeta potential of Egyptian bentonite/PAM mud increased at low PAM concentrations up to 10 mg/L. At high polyacrylamide concentrations, these properties decreased. To investigate the relation between rheological and electrical properties, potential energy profiles were constructed. Potential energy profile at 10 mg/L polyacrylamide–clay showed a high repulsion potential energy between clay surfaces, i.e., suspension stability attained. The most reliable clay suspension to meet the desired properties could be reached using 6% clay suspension concentration, 10 mg/L polyacrylamide, and temperature 40°C up to 24‐h aging time. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1496–1503, 2007     

Synthesis and characterization of a water‐soluble sulfonates copolymer of acrylamide and N‐allylbenzamide as enhanced oil recovery chemical

A novel water‐soluble polymer was prepared by copolymerization and sulfomethylation using acrylamide (AM) and N‐allylbenzamide (NABI) as raw materials under mild conditions. The effects of ratio of AM to NABI, initiator concentration, reaction temperature, pH, and monomer concentration on the copolymerization were studied. The sulfonates copolymer was characterized by infrared (IR) spectroscopy, ¹H NMR spectroscopy, elemental analysis, and atomic force microscopy (AFM). It was found that the sulfonates copolymer could achieve up to 25%, 30% retention rate of the viscosity at a high temperature (120°C) and a vigorous shear condition (1000 s^?1). It was also found that the sulfonates copolymer had moderate salt tolerance (NaCl, CaCl₂, and MgCl₂·6H₂O) and its viscosity could be restored to the original value when the shear rate changed from 170 to 510 s^?1 and 510 to 170 s^?1. At last, the enhanced oil recovery (EOR) of the sulfonates copolymer was tested by core flood, and with up to 10.6% EOR was afforded in presence of 5000 mg/L NaCl brine at 60°C. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and Optimization of 2-ethylhexyl Ester as Base Oil for Drilling Fluid Formulation

A stable ester was synthesized to overcome the ester hydrolysis problem during the drilling of oil or gas wells using a conventional ester-based drilling fluid. The thermal and hydrolytic stability of the produced ester was high owing to the transesterification method employed in this study. The reaction was performed using 2-ethylhexanol and methyl laureate esters in the presence of sodium methoxide as a catalyst. In order to obtain the optimum synthesis conditions, a response surface methodology (RSM) was appraised based on the central composite design (CCD). The optimum conditions were determined as follows: 0.6 wt.% catalyst, 70°C reaction temperature, 1:1.5 molar ratio, and 11.5 min of reaction time. The results of 77 wt.% 2-ethylhexyl ester (2-EH) illustrated a high agreement between the experimental and RSM models. The reaction product contained 77 wt.% 2-EH and 23% 2-ethylhexanol. The kinematic viscosity was 5 mm²/s at 40°C and 1.5 mm²/sec at 100°C; the specific gravity was 0.854, flash point was 170°C, and pour point was ?7°C. The produced product showed similar properties to the available commercial product. However, it was observed that the mud formulation using the synthesized base oil had superior rheological properties at 121°C.     

Synthesis and clay stabilization of a water‐soluble copolymer based on acrylamide,modular β‐cyclodextrin,and AMPS

A modular β‐cyclodextrin copolymer for clay stabilization was prepared from 2‐O‐(allyloxy‐2‐hydroxyl‐propyl)‐β‐cyclodextrin (XBH), acrylamide (AM), 2‐acrylamido‐2‐methyl propane sulfonic acid (AMPS), and sodium acrylate (NaAA) via redox free‐radical copolymerization. The effects of reactive conditions (such as initiator concentration, monomer ratio, reaction temperature, and pH) on the apparent viscosity of the copolymer were investigated and the optimal conditions for the copolymerization were established. The copolymer obtained was characterized by infrared spectroscopy, scanning electron microscope, viscosity measurements, rheological measurement, core stress test, and X‐ray diffractometry. The crystalline interspace of MMT could be reduced from 18.95323 Å to 15.21484 Å by copolymer AM/NaAA/AMPS/XBH. And this water‐soluble copolymer also showed remarkable anti‐shear ability, temperature resistance, and salt tolerance (1000 s^?1, viscosity retention rate: 35%; 120°C, viscosity retention rate: 75%; 10,000 mg/L NaCl, viscosity retention rate: 50.2%; 2000 mg/L CaCl₂, viscosity retention rate: 48.5%; 2000 mg/L MgCl₂, viscosity retention rate: 42.9%). © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Using Corn Husk Powder as a Novel Substrate to Produce a Surface Active Compound from Labrenzia aggregate KP‐5

In this study, surface active compound (SAC)‐producing bacterial isolates were evaluated for SAC production using corn husk powder (CHP) as a sole carbon source. From the 51 isolates screened, Labrenzia aggregate KP‐5 produced the highest SAC activity. The highest SAC production (3.51 g L^?1) was obtained when the strain was cultivated in a minimal salt medium containing 40 g L^?1 CHP and 1 g L^?1 commercial monosodium glutamate at 30 °C and 150 rpm after 51 h of cultivation. The produced SAC had the ability to decrease the surface tension of water from 72.0 to 25.5 mN m^?1, with the critical micelle concentration of 9 mg L^?1 (11.07 mM) and exhibited the highest emulsification activity (EA) of 81% against motor oil. The SAC showed stability at 4–121 °C and pH 4–10 against the surface and EA of vegetable oils and hydrocarbons, and showed tolerance at high salt concentrations (1–10% NaCl). The chemical structure of the SAC was confirmed as a rhamnolipid using Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and mass spectrometric analysis. The SAC did not exhibit inhibitory effects on various vegetables tested; however, strong inhibitory activity against Gram‐positive and Gram‐negative bacteria was observed. The application of SAC for microbial enhanced oil recovery by sand saturated with used lubricating oil resulted in above 89% of oil removal. The properties of the SAC we obtained from CHP have potential applications especially for microbial enhanced oil recovery and/or reducing the intensity of environmental contamination. In addition, the obtained SAC is a suitable alternative to antimicrobial agents.     

Amphoteric hydrolyzed poly(acrylamide/dimethyl diallyl ammonium chloride) as a filtration reducer under high temperatures and high salinities

Poly(acrylamide/dimethyl diallyl ammonium chloride) (PAD) samples were synthesized via solution polymerization. Hydrolyzed poly(acrylamide/dimethyl diallyl ammonium chloride) (HPAD) was prepared with NaOH as a hydrolyzation agent. Both PAD and HPAD were characterized by IR and NMR spectroscopy. Na₂SO₃ was added to slow down the decomposition of HPAD under elevated temperatures. The rheological and filtrate properties of the drilling fluids were investigated in saltwater mud. We found that 30 wt % NaCl hampered those properties. Increasing HPAD's percentage in the clay suspensions reduced the filtrate volumes and whereas increased the viscosities. A greater amount of HPAD added to the saltwater mud resulted in a smaller particle medium size and caused the ζ potential to move toward a less negative value. The hydrolysis degree of HPAD needed to be controlled in a proper range to optimize the reduction in filtration. Scanning electron microscopy photos showed that HPAD was distributed in the surface of the high‐temperature and high‐pressure filter cake as bridges. The drilling fluids with 3.5 wt % HPAD had an excellent tolerance to 30 wt % NaCl and a temperature of 200°C. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41581.     

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.     

Multifunctional characteristics of new carboxymethylcellulose‐based graft copolymers for oilfield drilling

New carboxymethylcellulose‐based graft copolymers with an amphoteric character were synthesized by grafting 2‐(dimethylamino)ethyl methacrylate onto carboxymethylcellulose using a persulfate‐initiated solution polymerization technique. Their multifunctional characteristics as an oilfield drilling–mud additive were investigated with respect to shale inhibition, viscosity building, and filtration control. It was shown that the graft copolymer with an appropriate grafting extent is characteristic of both good shale inhibition and mud properties and may overcome the limitations inherent in commonly used anionic and cationic polymeric additives. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 195–201, 2000     

Properties of high‐temperature drilling fluids incorporating disodium itaconate/acrylamide/sodium 2‐acrylamido‐2‐methylpropanesulfonate terpolymers as fluid‐loss reducers

The terpolymer of disodium itaconate (DIA), acrylamide (AM) and sodium 2‐acrylamido‐2‐methyl‐1‐propane sulfonate (SAMPS) was synthesized through free‐radical polymerization, and characterized using FTIR and TGA methods. The IR spectra of DIA‐AM‐SAMPS terpolymer confirmed that there was no olefinic band at 1635–1620 cm^?1, while the TGA results revealed that the terpolymer was of higher thermal stability than the SAMPS homopolymer. The filtrate volume reduced with increase of the terpolymer concentration before or after the aging test. The rheology properties of both fresh‐water mud and salt‐water mud were improved by DIA‐AM‐SAMPS terpolymer, and apparent viscosity (η_a); plastic viscosity (η_b) and yield point (τ₀) of salt‐water mud reached the smallest values at 1.2% of the terpolymer concentration after the aging test. The particle size data demonstrated that only a small change of the clay particle size occurred before and after the aging test at 220°C. This further confirmed the thermal stability of the terpolymer–clay dispersion from another point of view. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 3068–3075, 2002; DOI 10.1002/app.2335     

Efficiency of Egyptian drilling muds in the presence of cationic polyethylene imine and anionic polyacrylamide

The flow properties of Egyptian bentonite were studied using a combination of anionic polyacrylamide (MW = 1,000,000 g mol^?1) and cationic polyethylene imine (MW = 700,000 g mol^?1). This combination gave a significant effect on the clay suspensions to be qualified in the field of drilling mud depending on the sequence their addition. It was found that, by adding 50 mg/L cationic polyethylene imine followed by 10 mg/L anionic polyacrylamide, the rheological properties were improved using 6% Egyptian bentonite suspension, especially at 20°C. But, by reversing this addition sequence, the rheological properties of bentonite suspension were declined. The zeta‐potential value of bentonite suspension in the presence of 50 mg/L polyethylene imine was ?47 mV, while at 10 mg/L polyacrylamide was ?55 mV. But, on addition of 10 mg/L polyacrylamide to bentonite suspension followed by 50 mg/L polyethylene imine induced a reduction of the zeta‐potential value to ?51 mV when compared with that of polyacrylamide alone. By reversing the addition sequence, a very high stable suspension having zeta‐potential values of ?82 mV was obtained. Potential energy profiles were constructed to investigate the relation between rheological and electrical properties. Potential energy profile at 50 mg/L polyethylene imine followed by 10 mg/L polyacrylamide to bentonite suspension produced a high repulsion potential energy between clay surfaces, i.e. the suspension stability improved. By reversing that sequence, a significant decrease in the energy barrier was observed. The most reliable clay suspension as a drilling mud could be obtained by using 6% clay suspension concentration, with 50 mg/L polyethylene imine followed by 10 mg/L polyacrylamide, at 20°C up to 24 h aging time. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1487–1495, 2007     

Influence of polymerization conditions on the viscosity and yield of poly(phenylene sulfide ether)

High molecular weight poly(phenylene sulfide ether) (PPSE) was successfully synthesized by reaction of 4,4′‐dihydroxy diphenyl sulfide with 4,4′‐dichloro diphenyl sulfide in N‐methyl‐2‐pyrrolidone (NMP). The influence of polymerization conditions on the intrinsic viscosity and yield of PPSE was investigated and the optimized reaction condition was concluded. Reactions at about 180°C for 6 h along with sodium benzoate as an additive and monomer concentration of 0.588 mol/L NMP were found to produce the highest intrinsic viscosity (0.55 dL/g). Longer reaction time and/or higher temperature reduced the intrinsic viscosity and yield of the resulting product, probably due to side reactions, such as reductive dehalogenation and chemical degradation. X‐ray diffraction indicated that the polymer possessed of orthorhombic cell and had a high crystallinity of 65.8%. The high molecular weight PPSE is a crystalline polymer with T_m of 252°C and T_mc of 224°C. The polymer shows good chemical resistance, but is soluble in organic amide, halo‐hydrocarbon and oxohydrocarbon solvent at a temperature over 150°C. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and application of sodium 2‐acrylamido‐2‐methylpropane sulphonate/N‐vinylcaprolactam/divinyl benzene as a high‐performance viscosifier in water‐based drilling fluid

Aiming at good thickening ability and temperature resistance in water‐based drilling fluid, a novel copolymer viscosifier (SDKP) of sodium 2‐acrylamido‐2‐methylpropane sulfonate (NaAMPS) with N‐vinylcaprolactam (NVCL) and cross‐linking divinylbenzene (DVB) was prepared by micellar radical polymerization. The composition and molecular structure of optimal SDKP under the optimum reaction conditions was characterized by FT‐IR, ¹H‐NMR, and elemental analysis, and the molecular weight was determined by GPC. Thermal gravimetric analysis showed that the SDKP was even stable when the temperature was not higher than 330 °C. The performance of SDKP as viscosifier for aqueous, brines, and saturated brine bentonite drilling fluid was evaluated before and after aging tests at 230 °C for 16 h. The evaluation results indicated that the SDKP had excellent thickening ability, thermal resistant, and salt tolerance. HTHP rheology test showed that the SDKP containing drilling fluids displayed a thermo‐thickening effect in temperature range of 150 to 180 °C, which was beneficial to increase the viscosity and strength of fluids at high temperatures. Shear test showed that the SDKP illustrated a similar shear thinning to xanthan gum. ESEM observations demonstrated that the continuous three‐dimensional network was formed in the SDKP aqueous and brines solution, which was probably the main reason for its excellent thickening properties. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44140.     

Free radical kinetics of N‐methyl N‐vinyl acetamide polymerization at low conversions in aqueous media

N‐methyl N‐vinyl acetamide (NMNVA) monomer was polymerized at low conversions and its free radical kinetics were detailed using capillary dilatometry. The polymerizations were conducted isothermally, at 40°C using 2,2′‐azobis[2‐(2‐imidazolin‐2‐yl) propane dihydrochloride] (ABDH) as initiator. Monomer concentration and initiator concentration ranges were 1.10–1.70 mol · L⁻¹ and 1–4 mmol · L⁻¹, respectively. The aqueous polymerization media were kept at neutral pH. The rates of polymerization (R_p) and orders of reaction with respect to NMNVA and ABDH concentrations were evaluated and the kinetic expression was found to be ideal, with R_p ∝ [NMNVA]^1.07 [ABDH]^0.61. The polymers obtained were characterized by their viscosity numbers and correlation of viscosity average molecular weights was made with the amount of ABDH initiator. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 337–341, 2001     

Biodiesel production from Stichococcus strains at laboratory scale

BACKGROUND: This paper reports the results of an experimental campaign of autotrophic cultures of Stichococcus strains aiming at selecting the most promising strain for biofuel production. The strain selected—S. bacillaris 158/11—was cultivated in 1 L lab‐scale bubble column photobioreactors under fed‐batch and semi‐continuous conditions. A Bold basal medium supplemented with NaNO₃ as nitrogen source was adopted. Tests were carried out at 23 °C, 140 µE m^?2 s^?1, and air flow rate ranging between 0.4 and 4 vvm. Cultures were characterized in terms of pH, concentration of total nitrogen, total organic carbon, total inorganic carbon, biomass, lipid fraction and methyl‐ester distribution of transesterified lipids. RESULTS: S. bacillaris 158/11 proved to be the best strain to produce biodiesel. Methyl‐ester distribution was characterized by a large fraction of methyl palmitate, methyl linolenate, methyl linoleate, and methyl oleate along with phytol. The process photosynthetic efficiency—fraction of available light stored as chemical energy ‐ was about 1.5%. Specific biomass productivity was ～60 mg_DM L^?1 day^?1 under the semi‐continuous conditions tested. Total lipid productivity was 14 mg L^?1 day^?1 at a dilution rate of 0.050 L day^?1. CONCLUSION: S. bacillaris 158/11 is a potential strain for massive microalgae cultures for biofuel production. Higher biomass/total‐lipid productivity could be obtained in sunlight. Copyright © 2011 Society of Chemical Industry     

抗高温耐盐型钻井液用降滤失剂的合成与性能评价

选用对苯乙烯磺酸钠(SSS)、2-丙烯酰胺基-2-甲基丙磺酸(AMPS)、丙烯酰胺(AM)单体为原料,利用自由基聚合的方式,得到一种抗高温耐盐聚合物降滤失剂.通过傅里叶红外光谱分析(FT-IR)表明合成产物结构与设计结构相符.当降滤失剂加量为1.8%时,室温下和210℃下淡水基浆的滤失量分别为7.9mL和13.5mL;在25%NaCl和3%CaCl₂的盐水泥浆中,钻井液的滤失量分别为14.8mL和11.0mL.通过扫描电镜(SEM)可以分析钻井液形成的滤饼的微观结构,由此得到降滤失剂作用的机理是:当降滤失剂吸附在黏土表面时,降滤失剂可以使黏土颗粒在钻井液中分散,从而形成致密的滤饼来减少滤失量.     

Biodegradation of phenol at high concentration by a novel bacterium: Gulosibacter sp. YZ4

BACKGROUND: A novel bacterial strain, Gulosibacter sp. YZ4, has been isolated from activated sludge. Its application potential for phenol biodegradation has not yet been reported, therefore, in this study, biodegradation tests using strain YZ4 were executed under different conditions. RESULTS: The strain was identified as a new member of the genus Gulosibacter and nominated as Gulosibacter sp. YZ4. Phenol biodegradation tests showed that strain YZ4 could thoroughly biodegrade 1000 mg L^?1 phenol across a wide temperature range from 10 to 42 °C and pH range 5 to 11. Degradation of 1000 mg L^?1 phenol was not inhibited by the coexistence of p‐cresol or quinoline. During phenol degradation, strain YZ4 excreted both phenol hydroxylase and catechol 1,2‐dioxygenase to efficiently metabolize phenol. At 36 °C, pH 7.5, strain YZ4 could effectively degrade phenol at concentrations as high as 2000 mg L^?1 within 76 h. Haldane's model with the parameters obtained from the experiments could successfully describe the behavior of the phenol biodegradation by the strain YZ4. CONCLUSIONS: The strain YZ4 has a high potential for applications in phenol wastewater treatment in view of its adaptability to temperature and pH fluctuations and great tolerance to other coexistent toxics. Copyright © 2011 Society of Chemical Industry     

Experimental investigation of the rheological behaviors of polypropylene in a capillary flow

The rheological characterization of polymer melts is strongly related to their material properties. In this study, we focused on the rheological behaviors of a polypropylene (PP) melt through a capillary die. With an advanced twin‐bore capillary rheometer with dies measuring 1.0, 0.5, and 0.25 mm in diameter, experiments were performed over a shear‐rate range of 3 × 10² to 5 × 10³ s^?1 at three temperatures, 210, 220, and 230 °C. The results demonstrate that the geometry dependence of the PP viscosity relied on the die diameter and the temperature of the PP melt. The viscosity values of the PP melt in the 0.25‐mm diameter die were higher than were those in the 0.5‐ and 1.0‐mm dies at 220 and 230 °C. However, the viscosity values in all of the tested dies were similar at 210 °C. The tendency for the viscosity to decrease as the temperature of the polymer melt increased weakened in the 0.25‐mm diameter die. As a result, the pressure applied to the PP melt in the 0.25‐mm diameter die increased; this caused a decrease in the free volume between molecules. On the basis of the Barus equation, the contribution of pressure to the changed viscosity in each die at each of the tested temperatures was calculated and was found to be as high as 32.86% in the 0.25‐mm die at 230 °C. Additionally, the effect of the wall slip on the geometry dependence of the PP viscosity in the tested dies was investigated with a modified Mooney method. The values of the slip velocity revealed that wall slip occurred only in the 0.25‐mm die at 210 °C. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43459.     

Thermophysical properties of softened seawater and salt solutions over a wide temperature and pressure range

Investigations on the thermophysical properties of treated seawater and NaCl, Na₂SO₄ and MgCl₂ solutions of various concentrations have been carried out. Density has been investigated at 20–200°C temperatures and up to 200 bar pressures. The heat conductivity of seawater and solutions of various concentrations was studied at 20–300°C accounting for the solubility and the results analyzed. The viscosity of NaCl solutions was studied by the capillary method at 20–350° C and to 300 bars. The absolute value of viscosity decreases with increase in temperature, but the relative value increases. Heat capacitance of NaCl solutions investigated at 20–200°C, was found to decrease with increase in concentration. The surface tension of NaCl solutions was studied by the method of two capillaries at20–200°C.