Formation of mesoglobules in aqueous media from thermo-sensitive poly(ethoxytriethyleneglycol acrylate)

A series of six poly(ethoxytriethyleneglycol acrylate) (PETEGA) homopolymers were synthesized by atom transfer radical polymerization, reversible addition-fragmentation transfer polymerization, and anionic polymerization in order to cover a molecular weight range from 7,000 to 40,000 Da. The polymers exhibited a lower critical solution temperature (LCST) behavior in water, which was observed by the occurrence of a cloud point (CP) at around 35 °C. The transmittance of visible light versus temperature dependence overlapped during the cooling and the heating cycles, showing almost a complete lack of hysteresis. Moreover, instead of the occurrence of an uncontrolled macroscopic phase separation, stable colloidal aggregates (mesoglobules) of narrow distribution in particle size were formed in water at temperatures above the LCST of PETEGA at 1 g L⁻¹ solutions. The dimensions of the mesoglobules ranged from 91 to 235 nm, and particle size was not influenced by the molecular weight of PETEGA. Temperature changes caused considerable variations of the mesoglobules dimensions, which were smaller at higher temperatures. The addition of an anionic surfactant simultaneously increased the CP values by 4–6 °C and lowered the dimensions of the mesoglobules.     

Preparation and characterization of poly(MMA–BA)/nano-ATO hybrid latex via miniemulsion polymerization

The poly(methyl methacrylate–n-butyl acrylate)/nano-antimony-doped tin oxide (ATO) hybrid latices were prepared successfully via miniemulsion polymerization in the presence of emulsifier sodium dodecyl sulfate (SDS) and costabilizer hexadecane (HD). Several factors affecting the encapsulation efficiency of nano-ATO were studied. The prepared hybrid latices were characterized using transmission electron microscopy, dynamic light scattering particle size analysis, thermogravimetric analysis, and ultraviolet–visible-near infrared (NIR) spectra. The results show that the encapsulation efficiency of nano-ATO reaches the maximum value of 78.0% with 3 wt% of nano-ATO, 4 wt% of SDS, and 4 wt% of HD, and the mean diameter of hybrid latex particles is 87.5 nm. Both the weight loss ratio and the transmittance in NIR region of hybrid film decrease with the increasing nano-ATO amount. The prepared hybrid film containing nano-ATO exhibits excellent ability for shielding IR light with high transmittance in visible region, which can be used as transparent a heat-insulating coating for energy savings.     

Novel soluble fluorine-containing polyamides derived from 2-(4-trifluoromethylphenoxy)terephthalic acid and trifluoromethyl-substituted aromatic bis(ether amine)s

A series of new fluorine-containing polyamides were prepared directly by polycondensation of 2-(4-trifluoromethylphenoxy)terephthalic acid with four trifluoromethyl-substituted aromatic bis(ether amine)s in N-methyl-2-pyrrolidone (NMP) solution containing dissolved calcium chloride using triphenyl phosphite and pyridine as condensing agents. All the polymers showed excellent solubility in solvents such as NMP, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, pyridine, tetrahydrofuran, and acetone at room temperature. These polymers had inherent viscosities between 0.67 and 1.09 dL/g, and their weight-average molecular weights and number-average molecular weights were in the range of 48,200–68,000 and 29,500–39,400, respectively. The resulting polymers showed glass-transition temperatures between 189 and 214 °C and 10% weight loss temperatures ranging from 475 to 483 °C, and char yields at 800 °C higher than 50% in nitrogen. All polymers were amorphous and could be cast into transparent, flexible, and strong films from DMAc solutions with tensile strengths of 71–115 MPa, elongations at break of 6–9%, and tensile moduli of 2.7–3.2 GPa. These polymers had low dielectric constants of 3.14–3.31 (1 MHz), low moisture absorption in the range of 0.88–1.60%, and high transparency with an ultraviolet–visible absorption cut-off wavelength in the 320–340 nm range.     

Synthesis and characterization of potassium humate–acrylic acid–acrylamide hydrogel

A novel potassium humate–acrylic acid–acrylamide (KHA–AA–AM) superabsorbent polymer was prepared from the reaction among leonardite potassium humate, acrylic acid and acrylamide by free radical initiating process using ammonium persulfate as the initiator and N, N′-methylene bisacrylamide as the crosslinker. Various effects of synthesis conditions on superabsorbent polymer were studied and the optimal reaction condition was obtained with crosslinker concentration 0.44–0.74 wt%, initiator concentration 1.12–2.22 wt%, n(KOH)/n(AA) 0.51–0.70, monomer concentration 10.95–12.59 wt%, graft reaction temperature 83 ± 1°C, monomer mole ratio of acrylic acid to acrylamide 1.42–2.30, and potassium humate content 17.54 wt%. Under the optimal conditions, the solution absorbency of KHA–AA–AM superabsorbent polymer to deionized water, tap water, 0.5% carbamide solution and 0.9% NaCl solution were 733–756, 161–284, 786–825, and 76–83 g/g, respectively.     

Ring-opening polymerization of γ-glycidoxypropyltrimethoxysilane catalyzed by multi-metal cyanide catalyst

Ring-opening polymerizations of γ-glycidoxypropyltrimethoxysilane (GPTMS) were carried out by using multi-metal cyanide (MMC) catalyst and the synthesized homopolymer was a comb-shaped polymer with regular structure. The structure of the polymer obtained (P-GPTMS) was characterized by FTIR, ¹H-NMR, and ²⁹Si-NMR spectroscopy, and the molecular weight and its distribution were analyzed by size-exclusion chromatography with multi-angle laser light scattering (SEC-MALLS). The thermal behavior of P-GPTMS was investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). P-GPTMS with high molecular weight (M _n = 18,000–80,000) and narrow molecular weight distribution (1.10–1.35) were synthesized when the dosage of MMC catalyst was 0.1% and polymerization temperature was 130 °C. The molecular weight of the product could be adjusted by controlling the polymerization time. The T _g of P-GPTMS is in the range of −34 to −30 °C. On the basis of the TGA data, the decomposition rate of P-GPTMS reached its peak at 374.14 °C and the entire decomposition stopped at 600 °C.     

Synthesis of high refractive index polyamides containing thioether unit

Two kinds of aromatic dibenzoyl chloride monomer containing thioether unit 4,4′-Bis(4-chloroformylphenylthio)benzophenone (BP-DC) and 4,4′-thiodibenzoyl chloride (T-DC) were synthesized with two steps, which was reacted with diamine monomer containing thioether and amide unit to prepare a new kind of polyamide containing high quantity thio-ether group. The intrinsic viscosity of the polyamides was 0.76–0.90 dl/g obtained with optimum synthesis conditions. The polymers were found to have good optical properties: the optical transmittance of the aromatic polyamide film at 450 nm is higher than 80%, meantime the high quantity thio-ether unit provided the polymer with a high refractive index ranging from 1.691 to 1.696 and low birefringence of 0.007–0.008. At the same time the polymers had excellent thermal performance with glass transition temperature (T_g) of 226 °C–278 °C, initial degradation temperature (T_d) of 427 °C–439 °C. They showed improved solubility in polar aprotic solvents.     

Semicontinuous heterophase polymerization of methyl methacrylate in the presence of reactive surfactant HITENOL BC10

Semicontinuous heterophase polymerization was used to copolymerize methyl methacrylate (MMA) with reactive surfactant HITENOL BC10 (HBC10) at 60 °C using sodium dodecyl sulfate as pre-stabilizing agent and potassium persulfate as initiator. The mixture of MMA and HBC10 was added at constant rate in continuous mode varying the MMA/HBC10 ratio. High-polymerization rates were observed, decreasing as the MMA/HBC10 ratio decreased. Latexes with polymer content near 20% and polymer to surfactant (P/S) weight ratios between 5 and 15 were obtained. Particle sizes distribution were bimodal in all cases with a tendency to be monomodal as HBC10 concentration increased which was ascribed to enhanced particle stabilization by the presence of HBC10. The average particle diameters at the end of polymerizations for the first and second populations were around 10 and 50 nm, respectively. Very high average molecular weights were observed (1.4 × 10⁶ ≤ M _w  ≤ 2.1 × 10⁶ g/mol), which decreased when HBC10 concentration increased. The corresponding polydispersity indexes (M _w /M _n ) were in the range of 1.45–2.24.     

Synthesis and characterization of thioether-containing polyimides with high refractive indices

Colorless and transparent polymers with high refractive indices and high temperature resistance have aroused great interest in the industrial community. Here, a series of polyimides (PIs) were prepared from a newly synthesized thioether-containing dianhydride, 1,4-bis(3,4-dicarboxy-phenylenesulfanyl)-benzene dianhydride, and various diamines by a two-step polycondensation reaction. Some flexible and tough films were obtained by casting solutions of them in poly(amic acid) (PAA). The tensile strengths and elongations at break of these PI films were greater than 58 MPa and 10%, respectively. All of them were thermally stable up to 500 °C in both air and nitrogen. Their glass transition temperatures were in the range from 204.5 to 265.8 °C. PI films with a thickness of 10–20 μm showed good optical transparency in the visible light region. Their cutoff wavelengths were lower than 400 nm and their transmittance was higher than 80% at 460 nm. The thioether linkages in the PIs endowed them with high average refractive indices (n _AV) of 1.68–1.74 and low birefringence values (Δn) of 0.0085–0.0120.     

Corrosion performance of the electroless Ni–P coatings prepared in different conditions and optimized by the Taguchi method

This paper presents an experimental study on the influence of anionic surfactant sodium dodecyl sulfate (SDS), pH, substrate finishing and annealing temperature on the corrosion resistance of electroless nickel phosphorus (Ni–P) coatings using electrochemical techniques and optimization of process parameters based on the Taguchi method. Parameters were selected in three levels and L9 from orthogonal robust array design was used. Corrosion performance of the electroless Ni–P coatings was evaluated by polarization and electrochemical impedance spectroscopy (EIS). Scanning electron microscope (SEM), Energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) analysis were used for studying surface morphology and chemical composition of the electroless Ni–P coatings. The results showed that SDS surfactant causes increasing of corrosion resistance and improves surface morphology. Finally, optimum conditions were achieved as, surfactant concentration: 1.5 g L⁻¹, pH: 5.5, substrate finishing provided with emery paper no, 2000, and annealing temperature of 200 °C.     

Study on preparation and properties of novel reactive phenolic hydroxyl-containing polyimides

Novel reactive polyimides (PIs) containing phenolic hydroxyl functionalities were prepared from 4-(4-hydroxyphenyl)-2,6-bis[3-(4-aminophenoxy)phenyl]pyridine (m,p-HAPP) with various aromatic dianhydrides via one-step polycondensation procedure. The inherent viscosities of the PIs were 0.54–0.63 dL/g in DMF solution and most of them were readily soluble in common organic solvents such as DMF, DMAc, NMP, and m-Cresol, etc. Meanwhile, the PIs also had good thermal stability, with the glass transition temperature (T _g) of 221.7–310.5 °C, the temperature at 10 % weight loss of 524.1–579.3 °C in nitrogen atmosphere. Then commercial epoxy resin was cured in the presence of different ratios of the reactive polyimide, giving a series of polyimide modified epoxy films. Thermogravimetric analysis showed the increase of the temperature at 5 % weight loss of the films with the increase of the polyimide content; 296 °C for 0 %, 309 °C for 1.95 %, 337 °C for 3.85 % and 350 °C for 5.63 %.     

Properties of hydrophobically modified polyacrylamide with low molecular weight and interaction with surfactant in aqueous solution

Hydrophobically modified polyacrylamide (HMPAM), with a molecular weight of 10⁴ g/mol, was studied using a range of rheological methods and dynamic light scattering (DLS). DLS measurements indicate that the association of the modified polymer begins at low concentration. The modified polymer with high substitution forms transient networks below the critical concentration, but the networks are disrupted by the micelles formed by the polymer itself, and the networks do not contribute to viscosity enhancement. The modified polymers exhibited surface activity, and so they may be regarded as nonionic polymeric surfactants rather than thickeners. On the other hand, HMPAM is shown to interact with the surfactant SDS while PAM is inert to SDS. In the hydrophobic domains, it undergoes a surfactant‐induced association process; in the hydrophobe‐surfactant transition regions, the surfactant binds to the polymer in a noncooperative way and forms a polymer–surfactant complex. Contracted polymer chains begin to extend because of electrostatic repulsion, which can overcome the association at surfactant domains. The conformation of HMPAM polymer chains could be controlled by adding a specific amount of surfactant. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4348–4360, 2006     

Wettability of Aqueous Rhamnolipids Solutions Produced by Pseudomonas aeruginosa LBI

The wetting behavior of rhamnolipids produced by Pseudomonas aeruginosa LBI strain grown on waste oil substrate and sodium dodecyl sulfate (SDS) on glass, polyethylene terephthalate (PET), poly(vinyl chloride) (PVC), poly(ε-caprolactone) (PCL) and polymer blend (PVC–PCL) was investigated by the measuring contact angle of sessile drops, to determine the wetting characteristics of rhamnolipids. The comparison of the wetting profiles showed that at low SDS and rhamnolipid concentrations, the contact angle increased and when the concentration of the surfactant increased further, the contact angle decreased. The blend surface (PVC–PCL) showed better wettability than the homopolymers themselves and the blend changed the surface hydrophobicity of the polymer, making it more hydrophilic. The rhamnolipids produced by the LBI strain exhibited superior wetting abilities than the chemical surfactant SDS one. This is the first work that evaluates the wetting properties of rhamnolipids on polymer blends.

Investigation and optimization of SDS and key parameters effect on the nickel electroless coatings properties by Taguchi method

In this research, the influence of anionic surfactant sodium dodecyl sulfate (SDS), pH, substrate finishing, and annealing temperature on the surface morphology and hardness of the electroless nickel phosphorus (ENi–P) coatings were studied. Taguchi’s experimental design method was used. Parameters selected in three levels and L9 from orthogonal robust array design were employed. Surface roughnesses of the deposits were measured using a stylus instrument. Scanning electron microscope and x-ray diffraction analysis were implemented to study surface morphologies and phase composition, respectively. Microhardness of the ENi–P deposits was measured using a microhardness tester at three trials per sample. The results showed that addition of the SDS increases the microhardness and improves surface morphology. Finally, optimum condition was achieved as, surfactant concentration equal to 1.5 g/L, pH 5.5, substrate finishing provided with emery paper no. 2000, and annealing temperature equal to 400°C.     

Synthesis of <Emphasis Type="Italic">N</Emphasis>-(3-Oxapropanoxyl)dodecanamide and its Application in Surfactant-Polymer Flooding

Alkali-surfactant-polymer (ASP) flooding has been considered to be one of the useful tertiary oil recovery techniques. However, field tests in China have revealed that serious side effects may occur due to using alkali. Thus alkali-free SP flooding is more favorable in China. Unfortunately, surfactants effective in ASP flooding are usually ineffective in the absence of alkali and new surfactants need to be designed. In this paper N-(3-Oxapropanoxyl)dodecanamide as a pure compound and a mixture of homologues with narrow EO number distribution, synthesized by the reaction of lauroyl chloride with diglycolamine and addition of one ethylene oxide to coconut monoethanolamide respectively, are examined for their adaptability in SP flooding. It is found that, when mixed with betaines, both products can reduce Daqing crude oil/connate water interfacial tension to a magnitude of 10⁻³–10⁻⁴ mNm⁻¹ at 45 °C in a wide surfactant concentration range, 0.01–0.5 wt%, and oil displacement tests using natural cores indicates that a tertiary oil recovery of 18.6 ± 0.4% OOIP can be achieved by SP flooding with the N-(3-Oxapropanoxyl)dodecanamide as the main surfactant without adding any alkaline agent and neutral electrolyte. N-(3-Oxapropanoxyl)dodecanamide, as a nonionic surfactant without a cloud point and producible industrially from renewable materials, is an ideal surfactant for SP flooding in the absence of an alkaline agent.     

Synthesis and characterization of soluble polyamides from bis-[(4′-aminobenzyl)-4-benzamide] ether and various diacids

New aromatic diamine containing preformed amide, ether, and methylene; bis-[(4′-aminobenzyl)-4-benzamide] ether (BABE), was synthesized and characterized by FT-IR, NMR, and mass spectrometry. Aromatic–aliphatic polyamides were prepared from BABE with aliphatic/aromatic diacids via Yamazaki’s polymerization. The polyamides were characterized by FT-IR, ¹H NMR, inherent viscosity [η_inh], solubility tests, differential scanning calorimetry [DSC], thermogravimetric analysis [TGA], and X-ray diffraction [XRD]. Polyamides had inherent viscosities 0.35–0.84 dL/g, soluble in aprotic polar solvents like N-methyl-2-pyrrolidone, N, N-dimethyl acetamide and dimethyl sulphoxide containing LiCl due to an amorphous to partially crystalline morphology; as XRD patterns indicated. DSC analysis of polyamides showed glass transition temperatures 166–268 °C. Polyamides showed high thermal stability as they did not degrade below 300 °C, had 10% weight loss temperature higher than 375 °C, and the char yields at 900 °C were 22–55%; indicating potential applications as engineering materials.     

Synthesis, Characterization, Conductivity, Band Gap, and Thermal Analysis of Poly-[(2-mercaptophenyl)iminomethyl]-2-naphthol and Its Polymer–Metal Complexes

Oxidative polycondensation reaction conditions of [(2-mercaptophenyl)iminomethyl]-2-naphthol (2-MPIM-2N) were studied using oxidants such as air and NaOCl in an aqueous alkaline medium between 40 °C and 90 °C. The structure of poly-[(2-mercaptophenyl)iminomethyl]-2-naphthol (P-2-MPIM-2N) was characterized by ¹H- ¹³C NMR, FT-IR, and UV–Vis spectroscopy, size exclusion chromatography (SEC), and elemental analysis. At optimum reaction conditions, the yield of P-2-MPIM-2N was found to be 78 and 82% for air and NaOCl oxidants, respectively. From SEC measurements, the number-average molecular weight (M _n ), weight-average molecular weight (M _w ) and polydispersity index (PDI) of P-2-MPIM-2N are 2900, 3500 g mol⁻¹ and 1.207; 2200, 2500 g mol⁻¹ and 1.136, for air and NaOCl oxidants, respectively. Polymer–metal complexes were synthesized by the reaction of P-2-MPIM-2N with Co²⁺, Cu²⁺, Zn²⁺, Pb²⁺ and Cd²⁺ ions. The highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), and electrochemical band gaps (E^￠_g E^{\prime}_{g} ) of 2-MPIM-2N and P-2-MPIM-2N were −5.97, −2.66 and 3.31 eV and −5.82, −2.68 and 3.14 eV, respectively. The conductivity of polymer and polymer–metal complexes were determined in the solid state. Conductivity measurements of doped and undoped Schiff base polymer and polymer–metal complexes were carried out at room temperature and atmospheric pressure by the four-point probe technique using an electrometer. The conductivities of the polymer and polymer–metal complexes increased when iodine was used as doping agent.     

Novel surfactants for ultralow interfacial tension in a wide range of surfactant concentration and temperature

This work investigates the possibility of injecting dilute aqueous solutions of novel surfactants into the Yibal field (Sultanate of Oman). This was accomplished through an experimental protocol based on the following criteria: (i) compatibility of the surfactants with the high-saline reservoir water (∼200 g/L); (ii) low interfacial tension (IFT) between crude oil and reservoir water (less than 10⁻² mN m⁻¹); and (iii) maintaining the low IFT behaviour during the entire surfactant flooding. Novel surfactants selected in this study consist of a series of ether sulfonates (AES-205, AES-128, AES-506, and 7–58) and an amphoteric surfactant (6–105). These surfactants were found to be compatible with reservoir water up to 0.1% surfactant concentration, whereas 6–105 and 7–58 showed compatibility within the full range of surfactant concentration investigated (0.001–0.5%). All surfactant systems displayed dynamic IFT behavior, in which ultralow transient minima were observed in the range 10⁻⁴–10⁻³ mN m⁻¹, followed by an increase in the IFT to equilibrium values in the range 10⁻³–10⁻¹ mN m⁻¹. The results also showed that with respect to concentration (0.05–0.5%) and temperature (45–80°C), AES-205 and 7–58 surfactants exhibit a wide range of applicability, with the IFT remaining below 10⁻² mN m⁻¹, as required for substantial residual oil recovery. In addition, ultralow IFT were obtained at surfactant concentrations as low as 0.001%, making the use of these surfactants in enhanced oil recovery extremely cost-effective.     

Effect of acid treatment on structure and morphology of carbons prepared from pyrolysis of polyfurfuryl alcohol

Furfuryl alcohol (FA) was polymerized in aqueous solutions consisting of polyvinyl pyrrolidone (PVP) as a surfactant together with hydrochloric acid, phosphoric acid, or acetic acid as a catalyst, respectively. The polymerization degree of FA and the resulting structural difference after carbonization were examined. Experiments revealed that the presence of acids does indeed promote polymerization of FA, leading to a reduced defect population and an eventual formation of a more ordered structure in the carbonized products. This is particularly pronounced when hydrochloric acid was used as a catalyzer, forming “nonstick” polyfurfuryl alcohol (PFA) particles with a diameter ca. 0.5–1 μm. The polymeric particles were then converted into microporous carbon spheres with a specific surface area of 297 m²/g when calcined at 600 °C in argon atmosphere. On the contrary, FA in the rest of catalyst systems showed aggregated form with a pronouncedly reduced specific surface area ranging from 0.3 to 5.2 m²/g.     

Synthesis and properties of novel aromatic polyamides with non-conjugated bichromophoric units in the main chains

A dicarboxylic acid bearing two cinnamic acids units linked in their para positions by a methylene bridge was synthesized by the reaction of 4,4′-methylene-bis(benzaldehyde) and malonic acid, characterized by spectral and elemental analysis and used to prepare a series of novel photocrosslinkable aromatic polyamides through its reaction with various ether-bridged aromatic diamines. ¹H and ¹³C NMR, IR and UV spectroscopy confirmed the structure of the monomer and photopolymers. The resulting polymers with inherent viscosities of 0.65–1.14 dL/g were soluble in polar aprotic solvents, such as DMF, DMSO, DMAc and NMP, and showed good film-forming properties. Their weight-average and number-average molecular weights, determined by GPC (polystyrene standard), were in the range 57,400–84,300 and 24,000–40,900, respectively. The percent of water absorbed at 65% relative humidity varied between 1.57% and 2.35%. The polyamides exhibited glass transition temperatures between 202 and 239 °C, and they were stable up to a temperature of 350 °C in air. Wide-angle X-ray scattering diagrams did not show any crystalline reflection and no endothermic peak attributable to polymer melting was observed in DSC curves of the polymers. These photosensitive polymers exhibited strong UV absorption maxima both in solution and film state, and displayed three photochemical transformations under the UV exposure, viz. a trans-cis isomerization, favored in the early stage of UV irradiation, a bimolecular cyclodimerization, leading to the generation of a cyclobutane ring, and a photo-Fries rearrangement evidenced only in polymer solutions.     

Synthesis and characterization of poly(aryl ether ketone)s with fluorinated phenyl in the side chain

New bisphenol monomers, (4-fluorophenyl)hydroquinone (3b) and (3,4-difluoro phenyl)hydroquinone (3c), were synthesized in a two-step synthesis. Poly(aryl ether ketone)s (PAEKs) (4a–c) were derived from these fluorinated bisphenols and nonfluorinated bisphenol—phenylhydroquinone (3a) with 4,4′-diflourobenzophenone via a nucleophilic aromatic substitution polycondensation. The obtained polymers had inherent viscosities of 0.50–0.92 dL/g. Thermal analysis showed that the obtained PAEKs had excellent thermal properties, the glass transition temperatures ranged from 148 to 160 °C, and the temperatures at 5% weight loss (Td₅) were above 527 °C and the temperatures at 10% weight loss (Td₁₀) were above 544 °C in nitrogen. All the polymers showed excellent solubility and could dissolve in common organic solvents, such as DMSO, NMP, DMF, etc. So the films of them were easily cast from their solutions, which possessed good mechanical properties, with tensile strengths of 95.2–104.0 MPa, Young’s moduli of 2.68–3.06 GPa, and elongation at break of 15–32%. Furthermore, the prepared PAEKs displayed low dielectric constants (2.75–2.95 at 1 MHz) and hydrophobic character (contact angles for water: 83.9^o–98.4^o).