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1.
This research paper describes the development, optimization and in vitro characterization of chemically cross-linked pectin–polyvinyl alcohol-co-poly(2-Acrylamido-2-methylpropane sulfonic acid) semi-interpenetrating polymer network hydrogel [pectin–PVA-co-poly(AMPS) semi-IPN hydrogel] for controlled delivery of model drug tramadol HCl. Response surface methodology based on 32 factorial design was used for optimization and investigating the effect of independent factors: polymer-blend ratio (pectin:PVA = X 1) and monomer (AMPS = X 2) concentration on the dependent variables, swelling ratio (q 18th), percent drug release (R 18th, %), time required for 80 % drug release (t 80 %, h), drug encapsulation efficiency (DEE, %) and drug loaded contents (DLC, mg/g) in pectin-PVA-co-poly(AMPS) gels prepared by free radical polymerization. The optimized semi-IPN gel (FPP-10) showed controlled in vitro drug release (R 18th) of 56.34 % in 18 h, t 80 % of 30 h, and DEE of 23.40 %. These semi-IPN hydrogels were also characterized through SEM, FTIR, sol–gel analysis, swelling studies and drug release characteristics. Therefore, this newly synthesized polymeric network could be a potential polymeric system for controlled drug delivery of tramadol HCl for prolonged drug release. 相似文献
2.
Copolymers of N-acryloyl-N′-methylpiperazine (AcrNMP) and 2-hydroxyethyl methacrylate (HEMA) were synthesized by free radical solution polymerization in dioxane at 70 ± 1 °C, using 2,2′-azobisisobutyronitrile (AIBN) as initiator. The copolymer compositions were analyzed by the methods of FTIR spectroscopy and elemental analysis. Both the method of analysis yielded results that agreed reasonably well. The monomer reactivity ratios of the copolymerization were determined by the linearization methods of Finemann–Ross (FR) and Kelen–Tüdös (KT). The reactivity parameter results derived using FTIR analysis showed that the copolymerization yielded mainly alternating structure with reactivity ratios, r 1(AcrNMP) = 0.263 ± 0.011 and r 2(HEMA) = 0.615 ± 0.097 by F–R method and r 1 = 0.227 ± 0.074 and r 2 = 0.53 ± 0.15 by KT method. Microstructure data calculated by the method of Igarashi also supports the alternating structure (tendency) of the copolymer. Crosslinked polymer gels of this system exhibited remarkably high swelling of more than 500% in water at ambient temperature. 相似文献
3.
Beifang Liu Dongcheng Yang Hou Chen Hui Xu Wenxiang Wang Liangjiu Bai 《Iranian Polymer Journal》2017,26(5):355-364
Functional polymer brushes of poly(acrylonitrile-g-N,N?-dimethylaminoethyl methacrylate) were efficiently synthesized by a novel approach of combining Cu(0)-mediated controlled/“living” radical polymerization and nitrile click chemistry. The poly(acrylonitrile-g-N,N?-dimethylaminoethyl methacrylate) as a promising material exhibited excellent hydrophile–lipohile balance in the process of self-assembly and could autonomously develop the orderly structure micelle in N,N?-dimethylformamide/water mixture solvent for the potential application of a new drug delivery carrier. In the process of self-assembly, polyacrylonitrile acted as a backbone of the functional polymer brushes due to its hydrophobic feature and poly(N,N?-dimethylaminoethyl methacrylate) as the branch of functional polymer brushes due to its hydrophilic characteristic, which both were prepared by Cu(0)-mediated controlled/“living” radical polymerization with ethyl-bromoisobutyrate as initiator. Poly(N,N?-dimethylaminoethyl methacrylate) containing azide end group was synthesized by substitution reaction of poly(N,N?-dimethylaminoethyl methacrylate) containing bromine end groups with sodium azide in N,N?-dimethylformamide. The click reaction between the nitrile of polyacrylonitrile and the azide group of poly(N,N?-dimethylaminoethyl methacrylate) was carried out under ammonium chloride as catalyst in N,N?-dimethylformamide. The polymer was further confirmed by GPC, FTIR, 1H NMR and TGA. Meanwhile, the micelles with different morphologies were observed by TEM, and the particle diameter distribution of self-assembled micelle from the PAN-g-PDMAEMA brushes was determined by DLS. 相似文献
4.
Cathren E. Gowenlock Virginia Gomez James D. McGettrick Enrico Andreoli Andrew R. Barron 《Journal of Coatings Technology and Research》2017,14(1):195-205
Isonicotinate self-assembled monolayers (SAM) were prepared on alumina surfaces (A) using isonicotinic acid (iNA). These functionalized layers (iNA-A) were used for the seeded growth of copper films (Cu-iNA-A) by hydrazine hydrate-initiated electroless deposition. The films were characterized by scanning electron microscopy (SEM), electron-dispersive X-ray spectroscopy, atomic force microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and advancing contact angle measurements. The films are Cu0 but with surface oxidation, and show a faceted morphology, which is more textured (R q = 460 ± 90 nm) compared to the SAM (R q = 2.8 ± 0.5 nm). In contrast, growth of copper films by SnCl2/PdCl2 catalyzed electroless deposition, using formaldehyde (CH2O) as the reducing agent, shows a nodular morphology on top of a relatively smooth surface. No copper films are observed in the absence of the isonicotinate SAM. The binding of Cu2+ to the iNA is proposed to facilitate reduction to Cu0 and create the seed for subsequent growth. The films show good adhesion to the functionalized surface. 相似文献
5.
Yunsheng Xia Miao Lin Dongmei Ren Yuzhen Li Fengyun Hu Wenjun Chen 《Journal of Porous Materials》2017,24(3):621-629
Mesoporous nickel oxide (NiO) nanoparticles were synthesized by the thermal decomposition reaction of Ni(NO3)2·9H2O using oxalic acid dihydrate as the mesoporous template reagent. The pore structure of nanocrystals could be controlled by the precursor to oxalic acid dihydrate molar ratio, thermal decomposition temperature and thermal decomposition time. The structural characteristic and textural properties of resultant nickel oxide nanocrytals were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), N2 adsorption–desorption isotherm and temperature programmed reduction. The results showed that the most excellently mesoporous nickel oxide particles (m-Ni-1-4) with developed wormlike pores were prepared under the conditions of the mixed equimolar precursor and oxalic acid and calcined for 4 h at 400 °C. The specific surface area and pore volume of m-Ni-1-4 are 236 m2 g?1 and 0.42 cm3 g?1, respectively. Over m-Ni-1-4 at space velocity = 20,000 mL g?1 h?1, the conversions of toluene and formaldehyde achieved 90 % at 242 and 160 °C, respectively. It is concluded that the reactant thermal decomposition with oxalic acid assist is a key step to improve the mesoporous quality of the nickel oxide materials, the developed mesoporous architecture, high surface area, low temperature reducibility and coexistence of multiple oxidation state nickel species for the excellent catalytic performance of m-Ni-1-4. 相似文献
6.
The objective of this study was to investigate the influence of molecular structure on impact resistance (a n) and bending strength (σ) of photocured urethane-dimethacrylate polymer networks. Urethane-dimethacrylate (UDMA) monomers were synthesized through reaction of oligoethylene glycol monomethacrylate (OEGMMA) with diisocyanate (DI). OEGMMA varied within the length of the oligooxyethylene chain, which consisted of one to four oxyethylene units. DI varied in chemical character: aliphatic, cycloaliphatic or aromatic. The molecular structure of UDMA polymers was characterized by X-ray powder diffraction, which allowed the calculation of the d-spacing (d) and dimensions of microgel agglomerates (D). The measurements of the polymerization shrinkage were used for the determination of the degree of conversion (DC), whereas the concentration of double bonds was used as a measure of the crosslink density (q). It was found that all structural parameters depend on the UDMA chemical structure. The increasing length of the oligooxyethylene chains caused the decrease in d and q, in contrast to the increase in D and DC. The DI chemical character caused the increase in the DC and q accordingly: symmetrical cycloaliphatic or aromatic < asymmetrical cycloaliphatic and aromatic < substituted aliphatic < linear aliphatic. The compact packing and high DC in polymers derived from aliphatic DIs gave rise to the decrease in d and the increase in D. The non-planar conformation of cycloaliphatic DIs emerged in high d as well as D. The planar conformation of aromatic DIs resulted in the decrease in d as well as D. The study indicated that mechanical behavior of UDMA polymer networks can be explained in terms of the structural parameters. DC and q appeared to be the main factors determining both mechanical properties of poly(UDMA)s. The a n was also shown to be affected by d. Particularly high linear correlations were found on a semi-logarithmic scale for the DC and d with a n. a n increased as the DC increased, whereas d decreased. 相似文献
7.
Claudia Stefanutti Fabio Mazza Antonio Vivenzio Serafina Di Giacomo Giuseppina Perrone Mariarosaria Serra Antonello Bucci 《Lipids》2009,44(12):1141-1148
An open-labeled randomized trial with parallel groups was carried out to study the effects of Dif1stat® (Monascus purpureus–Linear aliphatic alcohols–Niacin) in the treatment of primary moderate hypercholesterolemia. The trial lasted 8 months. The patients, males and females, were assigned to two groups: A (#130), treated with diet, and B (#110) submitted to diet + Dif1stat®. After 4 months, group A did not show significant changes in Total cholesterol (TC), LDL-cholesterol (LDLC), HDL-cholesterol (HDLC) or non-HDL-cholesterol (non-HDLC). The same group, showed a reduction in TC (–22%), LDLC (–30%) and non-HDLC (–27%) after 8 months (P ≤ 0.001). After 4 months, TC (–21.3%), LDLC (–29%), and non-HDLC (–26%) were significantly lowered in group B (P ≤ 0.001). In group B, TC, LDLC and non-HDLC showed a further reduction after 8 months: –29.4, –38 and –37%, respectively (P ≤ 0.001). Even triglycerides (TG) decreased significantly (–33%) (P ≤ 0.001). After 8 months, group B showed a significant reduction of TG (–33%) (P ≤ 0.001), when compared to group A. Some safety parameters were significantly reduced in both groups: AST and γ-GT in group A after 4 and 8 months, as well as ALT, AST and γ-GT in group B after 8 months (P ≤ 0.001). Dif1stat®, given with a suitable diet, was well tolerated in the long-term and induced an anti-atherogenic plasma lipid and lipoprotein profile, in patients with moderate hypercholesterolemia. 相似文献
8.
A series of well-defined novel amphiphilic temperature-responsive graft copolymers containing PCL analogues P(αClεCL-co-εCL) as the hydrophobic backbone, and the hydrophilic side-chain PEG analogues P(MEO2MA-co-OEGMA), designated as P(αClεCL-co-εCL)-g-P(MEO2MA-co-OEGMA) have been prepared via a combination of ring-opening polymerization (ROP) and atom transfer radical polymerization (ATRP). The composition and structure of these copolymers were characterized by 1H NMR and GPC analyses. The self-assembly behaviors of these amphiphilic graft copolymers were investigated by UV transmittance, a fluorescence probe method, dynamic light scattering (DLS) and transmission electron microscopy (TEM) analyses. The results showed that the graft copolymers exhibited the good solubility in water, and was given the low critical temperature (LCST) at 35(±1) °C, which closed to human physiological temperature. The critical micelle concentrations (CMC) of P(αClεCL-co-εCL)-g-P(MEO2MA-co-OEGMA) in aqueous solution were investigated to be 2.0 × 10?3, 9.1 × 10?4 and 1.5 × 10?3 mg·mL?1, respectively. The copolymer could self-assemble into sphere-like aggregates in aqueous solution with diverse sizes when changing the environmental temperature. The vial inversion test demonstrated that the graft copolymers could trigger the sol-gel transition which also depended on the temperature. 相似文献
9.
Dietary PUFA Increase Apoptosis in Stomach of Patients with Dyspeptic Symptoms and Infected with <Emphasis Type="Italic">H. pylori</Emphasis>
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Rasoul Sharifi Mohammad Nouri Akram Eidi Zahra Noormohammadi Homayun Dolatkhah Masoud Shirmohammadi 《Lipids》2017,52(6):549-558
Drug-resistant strains of Helicobacter pylori and poor treatment response are the main reasons for the failure in eradicating it in patients. Polyunsaturated fatty acids (PUFA) have an inhibitory effect on bacterial growth. The aim of this study was to investigate the effect of PUFA in combination with standard triple therapy on apoptosis in H. pylori infected subjects with dyspeptic symptoms. This study was a double-blind clinical trial in which 34 H. pylori infected subjects with dyspeptic symptoms were randomly divided into two groups of 17 patients. The control group received standard triple therapy (amoxicillin, clarithromycin and omeprazole) and the experimental group received the standard therapy and PUFA for two weeks. Gene expression levels of caspase-3, BCL-2 and Bad proteins were studied with real-time PCR, while protein levels were quantified in frozen sections and using immunohistochemistry. Compared with the control group, a significant increase (p < 0.01) was observed in the expression of caspase-3 and Bad genes and a significant reduction (p < 0.05) in the expression of Bcl-2 gene. The protein level of active caspase-3 and Bad protein was significantly increased and the level of Bcl-2 protein was significantly decreased (p < 0.05). The results of this study show that oral administration of PUFA in combination with the standard triple therapy increased apoptosis in H. pylori-infected patients with dyspeptic symptoms. This increase in apoptosis may partly reduce drug resistance in these patients. Our results suggest inclusion of a dietary PUFA containing fatty acid supplement may improve treatment of patients that are refractory to the standard triple therapy. 相似文献
10.
Sania Ashraf Robina Begum Rida Rehan Weitai Wu Zahoor H. Farooqi 《Journal of Inorganic and Organometallic Polymers and Materials》2018,28(5):1872-1884
Poly(N-isopropylmethacrylamide-co-methacrylic acid) [p(NipAam-Mac)] microgels were synthesized and used as microreactors to fabricate silver nanoparticles. Pure and hybrid microgels were characterized using Ultraviolet–Visible (UV/Vis) spectroscopy, Fourier transform infra-red (FTIR) spectroscopy and transmission electron microscopy (TEM). Catalytic activity of hybrid microgels and mechanism of catalysis by this system was explored using different reaction conditions. At the same temperature, apparent rate constant (kapp) was found to be varied from 0.0414 to 0.7852 min?1 by increasing the concentration of NaBH4 from 2.49 to 22.41 mM at constant concentration of substrate and catalyst. However upon extra increase in concentration of NaBH4 from 22.41 to 37.35 mM reduced the value of kapp to 0.2178 min?1. Likewise, the value of kapp was found to be increased from 0.1242 to 0.5495 min?1 with increasing the concentration of 4-nitrophenol [Para-nitrophenol (p-Np)] from 0.063 to 0.079 mM keeping other parameters constant. Further increase in concentration of p-Np caused decline in the value of kapp. Kinetic data reveals that catalytic reduction of p-Np obeys Langmuir–Hinshelwood mechanism and p-Np is converted to p-Ap on the surface of the silver nanoparticles passing through various reaction intermediates. 相似文献
11.
Zhuangsheng Lin Eric A. Decker Julie M. Goddard 《Journal of Coatings Technology and Research》2016,13(2):395-404
Active packaging materials with surface immobilized metal chelating ligands were prepared by laminated photografting technique. The resulting materials presented transition metal scavenging properties with potential application in non-migratory antioxidant active packaging materials. Photografting of functional polymer ligands is typically performed in an oxygen-free environment, requiring a nitrogen inerting step, which limits potential industrial scale-up. Laminated photografting eliminates the need for nitrogen inerting by sandwiching the monomer solution between base material and an oxygen barrier layer. In this study, we demonstrated the ability to synthesize metal chelating active packaging materials, previously prepared by standard batch photografting, using a laminated photografting technique. The polypropylene-graft-poly(acrylic acid) and polypropylene-graft-poly(hydroxamic acid) chelating films prepared by laminated photografting presented similar surface chemistry as those reported previously, as characterized by infrared spectroscopy, and presented ferric ion chelating capacity of 182 ± 29 and 89 ± 10 nmol/cm2, respectively, at pH 5.0. The reported laminated photografting represents a coating technology with potential for adaptation to roll-to-roll manufacture of metal chelating films on an industrial scale. 相似文献
12.
Recently, a new cost-effective and less labor-intensive technique termed the “lipoprint LDL system” was developed to measure LDL particle size. However, the agreement between lipoprint and previously validated techniques, such as polyacrylamide gradient gel electrophoresis (PGGE), has never been tested. Therefore, we measured LDL size by lipoprint and PGGE in 16 obese subjects at 4 different time points. Lipoprint significantly overestimated (P = 0.003) integrated LDL particle size by 1.1 ± 3.0 Å when compared to PGGE. As for distribution, there was good agreement between methods for the estimation of large, medium, and small particles (mean difference between the methods was <3% for each parameter). Correlational analysis also revealed good relationships between methods for the proportion of large (r = 0.81, P < 0.0001), medium (r = 0.67, P < 0.0001), and small (r = 0.73, P < 0.0001) particles. In sum, although there is good agreement between lipoprint and PGGE for the determination of LDL size distribution, absolute LDL size values may differ between the two methods. 相似文献
13.
Seven novel high refractive index (HRI) acrylic monomers, comprising the quinolinone structural motive, have been synthesized and characterized. Cross-linked homo- as well as copolymers were prepared by photochemical bulk polymerization. The homopolymers show refractive indices at 589 nm (n 589) ranging from 1.60 up to 1.68, glass transition temperatures (T g) from 52 to 76 °C, and Abbe numbers (ν Abbe) of 19 to 25. Due to these parameters, the homopolymers are not suitable to be used directly for intraocular lens (IOL) manufacture, but the quinolinone monomers may be used as high refractive index components in copolymers. Potential mixtures were calculated theoretically and one example, a copolymer with PEA and PEGPEA, was prepared and characterized. The experimentally found values were T g?=?24 °C, n 589?=?1.593, and ν Abbe?=?28.3. Interestingly, the quinolinone compound which does not have any spacer between the polymerizable group and the high refractive index group appears to be the most useful one. The lightfastness of the new material fulfills the demands for IOLs. Quinolinone derivatives are promising new comonomers for high refractive index copolymers. 相似文献
14.
The development of new environment-friendly and efficient adsorbents has attracted a great interest in recent years. In this study, ethylene diamine-grafted chitosan copolymer (CS–MAA–EN) and triethylene tetramine-grafted chitosan copolymer (CS–MAA–TN) were synthesized to remove heavy metal ions from water. The influence of pH, adsorbents dosage and initial metal concentration were investigated to study the adsorbing effect of CS–MAA–EN and CS–MAA–TN for the removal of Cu2+ from aqueous solutions. The equilibrium adsorption capacities of CS–MAA–EN and CS–MAA–TN were 85.91 and 102.67 mg/g, respectively. The adsorption process was fitted better by the Langmuir isotherm model (R 2 = 0.9993, 0.9991) than the Freundlich isotherm model (R 2 = 0.8781, 0.8775). The adsorption kinetics confirmed that the adsorption mechanism could be better described by the pseudo-second-order equation. Two adsorbents showed excellent desorption efficiency (D e) and reuse ratio (R u). D e and R u of CS–MAA–EN were evaluated as 95.2 and 89.35 %, respectively, and those values of CS–MAA–TN were 92.73 and 83.25 %. The competitive adsorption results of the two adsorbents indicated that the rate sequence was Fe3+ > Cu2+ > Cr6+ > Ni2+ > Zn2+. 相似文献
15.
Polyhedral oligomeric silsesquioxane (POSS) and glycidyl methacrylate (GMA) are used to synthesize linear L-(PGMA-b-MA-POSS), dicephalous D-(PGMA-b-MA-POSS)2, and four-armed T-(PGMA-b-MA-POSS)4 through atom transfer radical polymerization (ATRP). These different structured POSS/GMA-containing copolymers are applied to build the porous films through breath-figures (BF) method. L-(PGMA-b-MA-POSS) is easy to form the ordered porous BF film, and T-(PGMA-b-MA-POSS)4 tends to form well-distributed BF film due to its high segment density which is beneficial to stabilize water drop. It is proven that solvent has a great effect on the morphologies of BF film. The perfect BF film is developed in the relatively wet atmosphere as 5–8 μm diameter of pores casted in THF and 2–4 μm diameter of pores casted in CH2Cl2 with regular morphology. The developed BF film has superior stability than the film developed in natural conditions due to the shorter stable balancing time. Therefore, it is believed that the obtained porous films show great potential in coating application. 相似文献
16.
Elena V. Kolyakina Ivan D. Grishin Andrey I. Poddel’sky Dmitry F. Grishin 《Journal of Polymer Research》2016,23(11):222
The influence of bis[4,6-di-tert-butyl-N-(2,6-dimethylphenyl)-o-iminobenzosemiquinono]cobalt (II) on radical polymerization of methyl methacrylate initiated by AIBN at 70–90 °C was studied. The introduction of cobalt complex bearing redox ligands into reaction media allows to provide polymerization of methyl methacrylate without self-acceleration with linear increase of molecular weight with conversion giving polymers with relatively low molecular weight distribution. The results of IR and NMR spectrometry and MALDI mass spectroscopy measurements show that the possibility of β-hydrogen transfer between complex and propagating radical during polymerization is minimal. The electron donating additives as tert.-butyl amine and pyridine have no activating effect on polymerization. The results of our experiments provided at different concentrations of initiator show that polymerization proceeds via degenerative chain transfer mechanism. 相似文献
17.
Gas Chromatographic Separation and Identification of Jacaric and Punicic 2-Ethyl-1-Hexyl Esters
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Siriluck Pojjanapornpun Kornkanok Aryusuk Narumon Jeyashoke Supathra Lilitchan Kanit Krisnangkura 《Journal of the American Oil Chemists' Society》2017,94(4):511-517
The present study demonstrates the separation of a critical pair of conjugated linolenic acid (CLN) isomers—jacaric acid (JA; c8, t10, c12-18:3) and punicic acid (PA; c9, t11, c13-18:3)—on a 60-m conventional Supelcowax 10 column. The alkyl esters of different alcohols (C1–C8) of JA and PA were prepared and analyzed isothermally at 220, 230 and 240 °C. The adequacy of their separation was determined from the separation factors (α) and peak resolutions (R s). Acceptable resolution (R s = 1.01) of JA and PA was obtained with their 2-ethyl-1-hexyl ester derivatives at a column temperature of 230 °C. In addition, the Gibbs energy of transfer from solution to gas of the three double bonds \((\Delta_{\text{sln}}^{\text{g}} G_{\text{u}}\)) could be used to describe the interactions of the double bond with the stationary phase. Characterization of 2-ethyl-1-hexyl esters of Jacaranda mimosifolia seed oil at 230 °C demonstrates that the oil contains JA and α- and β-calendic acid as a CLN without the presence of PA. The results suggested that JA could be resolved from PA on a 60-m Supelcowax 10 column as the ethyl hexyl ester. 相似文献
18.
19.
Photo-responsive microgels were prepared by taking advantage of the interaction between Tween 20-coumarin conjugate (TCC) and polymeric β-cyclodextrin (PβCD). TCC was prepared by covalently attaching coumarin to the hydroxyl group of the head (PEO segment) of Tween 20. The molar ratio of coumarin residue and Tween 20 was 1: 1, determined on the 1H NMR spectrum. PβCD was prepared by reacting epichlorohydrins (EPI) with the hydroxyl groups of βCDs. The primary hydroxyl groups participated in the polymerization reaction, evidenced by the 13C NMR spectrum. The CD content in PβCD, determined by a colorimetric method, was 37.4%. Microgels were prepared by adding TCC to the aqueous solution PβCD (20%, w/v) so the molar ratio of TCC to βCD residue was 0.72: 1. The shape was spherical on SEM photo and optical microscopic photo, and the diameter, measured on light scattering equipment, was a few micrometers. The size dramatically decreased by the irradiation of λ at 365 nm, possibly due to the photo-dimerization of coumarin residue of TCC. Thr size of the photo-treated microgel markedly increased by the irradiation of λ at 254 nm, possibly due to the de-dimerization of the coumarin residue dimers. 相似文献
20.
Synthesis,Characterization and Surface Properties of Amidosulfobetaine Surfactants Bearing Odd-Number Hydrophobic Tail
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S. M. Shakil Hussain Mustapha Alao Animashaun Muhammad Shahzad Kamal Nisar Ullah Ibnelwaleed A. Hussein Abdullah S. Sultan 《Journal of surfactants and detergents》2016,19(2):413-420
Three amidosulfobetaine surfactants were synthesized namely: 3-(N-pentadecanamidopropyl-N,N-dimethyl ammonium) propanesulfonate (2a); 3-(N-heptadecanamidopropyl-N,N-dimethyl ammonium) propanesulfonate (2b), and 3-(N-nonadecanamidopropyl-N,N-dimethyl ammonium) propanesulfonate (2c). These surfactants were prepared by direct amidation of commercially available fatty acids with 3-(dimethylamino)-1-propylamine and subsequent reaction with 1,3-propanesultone to obtain quaternary ammonium salts. The synthesized surfactants were characterized by IR, NMR and mass spectrometry. Thermogravimetric analysis (TGA) results showed that the synthesized surfactants have excellent thermal stability with no major thermal degradation below 300 °C. The critical micelle concentration (CMC) values of the surfactants 2a and 2b were found to be 2.2 × 10?4 and 1.04 × 10?4 mol/L, and the corresponding surface tension (γCMC) values were 33.14 and 34.89 mN m?1, respectively. The surfactants exhibit excellent surface properties, which are comparable with conventional surfactants. The intrinsic viscosity of surfactant (2b) was studied at various temperatures and concentrations of multi-component brine solution. The plot of natural logarithm of relative viscosity versus surfactant concentration obtained from Higiro et al. model best fit the surfactant behavior. Due to good salt resistance, excellent surface properties and thermal stability, the synthesized surfactant has potential to be used in various oil field applications such as enhanced oil recovery, fracturing, acid diversion, and well stimulation. 相似文献