Ultrasound-assisted Polymerization Research Articles

A novel approach to control the temperature of chocolate in a packaging box using ultrasound-assisted nanoencapsulated eutectic phase change materials powder

A binary eutectic of n-dodecanol and cetostearyl alcohol was prepared as a phase change material (PCM) and then nanoencapsulated (nPCM) by ultrasound-assisted polymerization for temperature-managing applications. Eutectic PCMs (e-PCMs) and nanocapsules powder were examined through differential scanning calorimetry (DSC). e-PCM had 18.8 °C (melting point) and 192.6 J/g (latent heat), respectively, while nanocapsules powder showed 134.0 J/g (latent heat) with a similar melting point. Fourier transform infrared spectroscopy (FTIR) was used to examine the inert nature of the e-PCM towards shell materials used for synthesizing nanocapsules powder. Morphology, core/shell structure, particle size distribution (avg. ∼ 260 nm), and thermal stability prepared powder were confirmed by the field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), dynamic light scattering (DLS), and thermogravimetric analyzer (TGA). Therefore, the prepared nanocapsules powder was used to show performance in managing the temperature inside a temperature-controlled packaging (TCP) box.

Super-hydrophilic electrospun PAN nanofibrous membrane modified with alkaline treatment and ultrasonic-assisted PANI in-situ polymerization for highly efficient gravity-driven oil/water separation

Polyaniline (PANI) is utilized in numerous membrane-based oil/water emulsion separation systems due to its simple synthesis, low cost, chemical stability, and abundant amino functional groups. However, it is still challenging to benefit from the highest efficiency of the PANI-modified membrane in oil/water separation. Herein, PANI was favorably functionalized electrospun polyacrylonitrile (PAN) nanofiber through the establishment of electrostatic interaction and hydrogen bonding between aniline monomer and alkalinized PAN (APAN) nanofibers followed by aniline polymerization under ultrasonic irradiation (APAN/PANI-S) for high-performance oil/water emulsion separation. The uniform and efficient coating of PANI on APAN nanofiber led to the APAN/PANI-S nanofibrous membrane demonstrating outstanding physical stability in harsh acidic and basic conditions. In addition, the APAN/PANI-S nanofibrous membrane illustrated a super-hydrophilic and underwater super-oleophobic surface nature, which resulted in an extraordinary water flux of about 2289 LMH and oil rejection of around 99.69 % in oil/water separation under the gravity driving force. Furthermore, the homogenous penetration of PANI across the APAN nanofibrous membrane as a result of ultrasound-assisted polymerization caused the APAN/PANI-S nanofibrous membrane to show excellent mechanical stability (∼14.07 MPa) and antifouling properties (water flux of>981 LMH and oil rejection above 98 %) during 15-cycle oil/water emulsion separation. These results indicate that the APAN/PANI-S nanofibrous membrane with superior oil/water separation performance could be a promising candidate from a practical application point of view.

Experimental and biophysical interaction studies of alanine modified polyaniline with bovine serum albumin and human serum albumin: Influence of alanine modification on the spectral, morphological and electronic properties

The present work reports for the first time, modification of aniline with alanine (Ala) in mole ratios of 80–20, 50–50 and 20–80 via ultrasound-assisted polymerization. The formation of Ala-incorporated polyaniline (PANI) was confirmed via FTIR, UV–visible and SEM studies. The geometry optimization, Mulliken charge distribution, vibrational as well as electronic spectral analysis was carried out using Gaussian 09 software with B3LYP/6311 G(d) basis set. Quenching of bovine serum albumin (BSA) and human serum albumin (HSA) by Ala/PANI followed the static mechanism which was confirmed by the fluorescence studies and Stern Volmer plots. The binding constant (Kb) values were found to be higher for Ala-PANI oligomers (∼105 LM−1) containing higher loading of PANI. The binding affinity of Ala/PANI towards BSA as well as HSA was found to be fairly good and the docking studies established that hydrogen bonding as well as Van der Waal’s forces played a significant role in the binding process.

Ultrasound-assisted polymerization of benzoquinone (BQ) with triphenylamine (TPA): comparison of computational and experimental studies

The present preliminary work reports chemical oxidative polymerization of benzoquinone with triphenylamine via ultrasound-assisted technique. The obtained polymer was characterized using Fourier transform infrared spectroscopy analysis, while the electronic transitions were analyzed via ultraviolet–visible studies. The experimental data were compared with the theoretically computed results using Gaussian 09 software. Theoretical IR and UV spectra were computed using DFT/B3LYP method with 6-311G basis set, and the results of spectral analysis were found to be in good agreement with the experimental ones. TEM analysis revealed flower-like particles, while the XRD results confirmed the formation of semi-crystalline polymers. Fluorescence studies exhibited emission around 800 nm, while the relative quantum yield was calculated to be 0.58. The synthesized polymer therefore holds immense potential to be used as near infrared bioimaging agent.

Experimental and Theoretical Studies of Novel Azo Benzene Functionalized Conjugated Polymers: In-vitro Antileishmanial Activity and Bioimaging

To study the effect of insertion of azobenzene moiety on the spectral, morphological and fluorescence properties of conventional conducting polymers, the present work reports ultrasound-assisted polymerization of azobenzene with aniline, 1-naphthylamine, luminol and o-phenylenediamine. The chemical structure and polymerization was established via Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (1H-NMR) spectroscopy, while the electronic properties were explored via ultraviolet-visible (UV-vis) spectroscopy. Theoretical IR and UV spectra were computed using DFT/B3LYP method with 6–311G basis set while theoretical 1H-NMR spectra was obtained by gauge independent atomic orbital (GIAO) method. The theoretically computed spectra were found to be in close agreement with the experimental findings confirming the chemical as well as electronic structure of the synthesized polymers. Morphology was investigated by X-ray diffraction and transmission electron microscopy studies. Fluorescence studies revealed emission ranging between 530–570 nm. The polymers also revealed high singlet oxygen (1O2) generation characteristics. In-vitro antileishmanial efficacy as well as live cell imaging investigations reflected the potential application of these polymers in the treatment of leishmaniasis and its diagnosis.

Ultrasound-Assisted Polymerization of Dyes with Phenylenediamines: Facile Method To Design Polymeric Photosensitizers with Enhanced Singlet Oxygen Generation Characteristics and Anticancer Activity

The present work reports for the first time ultrasound-assisted polymerization of Alizarin Red (AR), Amido Black 10B (AB-10B), and 1,4-benzoquinone (BQ) with o- and p-phenylenediamines. The synthes...

Porous Polypyrrole/Graphene Oxide Functionalized with Carboxyl Composite for Electrochemical Sensor of Trace Cadmium (II)

Cadmium (II) sensing utilizing three-dimensional graphene/polypyrrole oxides was applied and evaluated for the environmentally relevant analytes. Driven by the need to detect trace Cd (II), we prepared a porous graphene oxide-polypyrrole (pGO/PPy) polymer nanocomposite modified sensor for electrochemical trace analysis of Cd (II). The pGO/PPy was prepared by polypyrrole wrapped with graphene oxide using ultrasound-assisted polymerization and graphene oxide functionalized with carboxyl, which was modified on the sensing electrode for pre-concentration and enhanced the absorption of heavy metal ions. Three-dimension graphene oxide and interconnected porous structure of polypyrrole were fabricated by electro-polymerization and sonication to enhance the pre-concentration factors and the sensitivity for cadmium determination. The cadmium sensor fabricated with pGO/PPy nanocomposite displayed a displayed a considerable sensitivity within the linear range from 1μg·L−1 to 100 μg·L−1, a detection limit of 0.05 μg·L−1 2-orders-lower cadmium than the WHO standard limit. The cadmium sensor could be applied in tap, pond and river water with a high selectivity minimizing electroactive, interfering ions.

Ultrasound-assisted polymerization of P(AM-DMDAAC): Synthesis, characterization and sludge dewatering performance

P(AM-DMDAAC) (PDA) was synthesized by ultrasound assisted polymerization with dimethyl diallyl ammonium chloride (DMDAAC) and acrylamide (AM) as the monomers. The reaction conditions of polymerization were investigated by single factor approach and L16 (45) orthogonal array. Results showed that the intrinsic viscosity of PDA could reach 14.6 dL/g with the optimum polymerization conditions as following: monomer concentration of 30%, temperature of 30°C, ultrasound time of 1h, monomer mass ratio (m(DMDAAC):m(AM)) of 2:8, initiator concentration of 0.4‰, sodium benzoate concentration of 0.5‰, ethylene diamine tetraacetic acid (EDTA) concentration of 0.5‰, solution pH value of 6 and urea concentration of 0.3‰. The self-made PDA was characterized by several instruments. The results of FTIR and 1HNMR indicated that PDA was successfully polymerized by AM and DMDAAC. DTA-TGA showed that PDA was very stable at room temperature. And SEM proved the porous and mushroom shaped structure of PDA. For PDA used as flocculant in sludge dewatering experiment, the results showed that the filter cake moisture content and the supernatant turbidity could be reduced to 66.3% and 24.1 NTU, respectively. Comparing with other four cationic polyacrylamides, the filter cake moisture content could be reduced by 2.0-7.4% and the supernatant turbidity could be reduced by 18.3-32.1% via using self-made PDA, that was to say, the dewatering efficiency of self-made PDA was the best. Besides, the optimal dosage of self-made PDA was the least, and the cost analysis showed that it was also favorable, a 14.6-39.3% cost could be saved by using self-made PDA.

MoS2 nanolayer coated carbon spheres as an oil additive for enhanced tribological performance

Submicrometer-sized carbon spheres coated with a MoS2 nanolayer (CS-MoS2) have been synthesized and investigated as a viable oil additive to enhance the tribological properties of conventional oil lubricants in both the boundary and mixed lubrication regimes. Submicrometer-sized carbon spheres (CS) are obtained by the rapid ultrasound-assisted polymerization of resorcinol and formaldehyde, and MoS2 is subsequently coated onto the CS particles via controlled heat treatment. The tribological performance of the proposed lubricant mixture was studied using a tribometer under the ball-on-disk and cylinder-on-disk configurations. The hybrid lubricant is comprised of 1 wt % CS-MoS2 particles dispersed in a standard engine oil (SAE 5W30) and demonstrated a significant reduction in friction and wear (15–35%) relative to the pristine reference oil under various disk speeds. Raman spectroscopic investigation of the wear scars following the tribological tests suggest high chemical stability of the CS-MoS2 particles. The enhanced tribological performance of the CS-MoS2 and oil mixture lubricant is attributed to both the spherical carbon particles and the superior lubrication of the MoS2 nanolayer. The combination of these tribological properties demonstrated by the secondary particle could prevent direct contact between sliding surfaces and act as a particulate ball bearing at the nanoscale.

Ultrasmooth submicrometer carbon spheres as lubricant additives for friction and wear reduction.

Ultrasmooth submicrometer carbon spheres are demonstrated as an efficient additive for improving the tribological performance of lubricating oils. Carbon spheres with ultrasmooth surfaces are fabricated by ultrasound assisted polymerization of resorcinol and formaldehyde followed by controlled heat treatment. The tribological behavior of the new lubricant mixture is investigated in the boundary and mixed lubrication regimes using a pin-on-disk apparatus and cylinder-on-disk tribometer, respectively. The new lubricant composition containing 3 wt % carbon spheres suspended in a reference SAE 5W30 engine oil exhibited a substantial reduction in friction and wear (10-25%) compared to the neat oil, without change in the viscosity. Microscopic and spectroscopic investigation of the carbon spheres after the tribological experiments illustrated their excellent mechanical and chemical stability. The significantly better tribological performance of the hybrid lubricant is attributed to the perfectly spherical shape and ultrasmooth surface of carbon sphere additive filling the gap between surfaces and acting as a nanoscale ball bearing.

Ultrasound-assisted polymerization of methyl methacrylate using the reactive surfactant Hitenol BC10 in a semicontinuous heterophase process

Semicontinuous heterophase polymerization was used to polymerize methyl methacrylate (MMA) with the reactive surfactant Hitenol BC10 (polyoxyethylene(10)alkylphenyl ether ammonium sulfate, HBC10) in the presence of ultrasound at 50 °C. The effects of HBC10 concentrations and the monomer addition rate (R a) on kinetics, colloidal behavior, and molar masses were studied. Latexes with polymer content between 20 and 24 % were obtained. Particle size distributions (PSD) of latexes without HBC10 were bimodal, whereas those obtained in the presence of HBC10 were mono-modal in all cases. The average particle diameters (D p) were in the range of 39–63 nm decreasing with the HBC10 concentration and increasing with R a. Polymerization rates (R p) were decreased, by increasing the HBC10 concentration, which was ascribed to chain transfer events to HBC10. It was also observed that R p increased with R a; however, monomer-starved conditions were favored at lower R a values. Very high-average molecular weights were observed (1.63 × 106 ≤ M w ≤ 2.34 × 106 g/mol) which decreased when HBC10 concentration increased, and increased with R a. The corresponding polydispersity indexes (M w/M n) were in the range of 1.55–2.30, showing relatively wide molar masses distributions. It was observed from differential scanning calorimetry that polymers with HBC10 presented two T g (123 and 178 °C) which was ascribed to HBC10 incorporated to PMMA chain, corroborated by 1H NMR.

Ultrasound assisted polymerization for synthesis of ZnO/Polypyrrole composites for zinc/nickel rechargeable battery

ZnO/Polypyrrole (PPy) composites are synthesized by ultrasound assisted chemical polymerization of PPy in the presence of ZnO particles. With different initial content of pyrrole, granular and layered ZnO/PPy composite are formed. The fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) are adopted to characterize the as-prepared samples. ZnO/PPy composites are used as anode material for Zn/Ni batteries. Galvanostatic charge/discharge experiments, cyclic voltammograms (CV) and electrochemical impedance spectroscopy (EIS) are conducted to evaluate the cycle performance of electrodes. ZnO/PPy composites show superior capacity stability, more stable charge plateau and higher discharge plateau compared to conventional ZnO electrode. Furthermore, rate performance is also improved by ZnO/PPy composites.

Removal of Brilliant Green from wastewater using conventional and ultrasonically prepared poly(acrylic acid) hydrogel loaded with kaolin clay: A comparative study

The present work deals with the removal of Brilliant Green dye from wastewater using a poly(acrylic acid) hydrogel composite (PAA-K hydrogel) prepared by incorporation of kaoline clay. The composite has been synthesized using ultrasound assisted polymerization process as well as the conventional process, with an objective of showing the better effectiveness of ultrasound assisted synthesis. It has been observed that the hydrogel prepared by ultrasound assisted polymerization process showed better results. The optimum conditions for the removal of dye are pH of 7, temperature of 35°C, initial dye concentration of 30mg/L and hydrogel loading of 1g. The extent of removal of dye increased with an increase in the contact time and initial dye concentration. A pseudo-second-order kinetic model has been developed to explain the adsorption kinetics of dye on the PAA-K hydrogel. Thermodynamic and kinetic parameters indicate that the adsorption process is spontaneous in nature and the PAA-K hydrogel prepared by ultrasound process is a promising adsorbent compared to conventional process. The obtained adsorption data has also been fitted into commonly used adsorption isotherms and it has been found that Freundlich as well as Langmuir adsorption isotherm models fits well to the experimental results.

Ultrasound assisted polymerization of N-vinyl imidazole under phase-transfer catalysis condition – A kinetic study

The kinetics of phase-transfer catalyzed radical polymerization of N-vinyl imidazole (NVI) using potassium peroxy disulfate (PDS) as water soluble initiator and tetraoctylammonium chloride (TOAC) as PTC has been investigated in ethyl acetate/water two phase system assisted by ultrasound irradiation at constant temperature 60+1°C under nitrogen atmosphere. and. The rate of polymerization increases with an increase in concentrations of NVI, PTC and PDS. The order with respect to [NVI], [PTC], and [PDS] were found to be 1.01, 1.03 and 0.52 respectively. Based on the observed results a suitable mechanism has been proposed to account for the experimental observations followed by a discussion on its significance.

2D-Infrared Thermography Monitoring of Ultrasound-Assisted Polymerization of Water-Soluble Monomer in a Gel Process

This paper describes a process based on the ultrasound-assisted polymerization of a water-soluble monomer at a high concentration, which is known as a gel polymerization process. Polymerization is triggered by the ultrasound-assisted decomposition of the initiating species. This highly exothermic polymerization reaction can sustain a localized reaction front that propagates throughout an unstirred medium, as in frontal polymerization. Evidence for the controlled nature of thermal propagation alongside a gel process is presented by online 2D-infrared (IR) thermography monitoring. In addition, the effects of thermal propagation on the molar mass distributions are described. Specifically, the use of ultrasound not only suppresses the so-called “fingering” of frontal polymerization but also avoids any alteration of the molar mass distribution of the polymer.

Ultrasound assisted polymerization of MMA and styrene in near critical CO 2

It has been shown that ultrasonic irradiation can induce the formation of free radicals in liquid carbon dioxide. In this work, ultrasonically induced polymerization of MMA or styrene in liquid CO 2 was successfully performed. With ultrasound irradiation for 2–6 h and the absence of any form of stabilizer, discrete polymer particles have been generated and the resulting polymer formed as a fine powder. The results also show that the irradiation period and CO 2:MMA ratio have a significant effect on both the molecular weight and molecular weight distribution for the resulting polymer.