scholarly journals Kinetics and Modeling of Aqueous Phase Radical Homopolymerization of 3-(Methacryloylaminopropyl)trimethylammonium Chloride and its Copolymerization with Acrylic Acid

Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1352
Author(s):  
Ikenna H. Ezenwajiaku ◽  
Emmanuel Samuel ◽  
Robin A. Hutchinson
Keyword(s):  
Acrylic Acid ◽  
Electrostatic Interactions ◽  
Monomer Conversion ◽  
Trimethylammonium Chloride ◽  
Experimental Conditions ◽  
Monomer Composition ◽  
Initial Monomer ◽  
Monomer Content ◽  
Kinetics Of

The radical homopolymerization kinetics of 3-(methacryloylaminopropyl) trimethylammonium chloride (MAPTAC) and its batch copolymerization with nonionized acrylic acid (AA) in aqueous solution are investigated and modeled. The drift in monomer composition is measured during copolymerization by in situ NMR over a range of initial AA molar fractions and monomer weight fractions up to 0.35 at 50 °C. The copolymer becomes enriched in MAPTAC for monomer mixtures containing up to 60 mol% MAPTAC, but is enriched in AA for MAPTAC-rich mixtures; this azeotropic behavior is dependent on initial monomer content, as electrostatic interactions from the cationic charges influence the system reactivity ratios. Models for MAPTAC homopolymerization and AA-MAPTAC copolymerization are developed to represent the rates of monomer conversion and comonomer composition drifts over the complete range of experimental conditions.

In situ Time-Resolved Small-Angle X-ray Scattering Reveals the Formation Kinetics of Polyelectrolyte Complex Micelles

2019 ◽  
Author(s):  
Hao Wu ◽  
Jeffrey Ting ◽  
Siqi Meng ◽  
Matthew Tirrell
Keyword(s):  
Small Angle ◽  
Self Assembly ◽  
Electrostatic Interactions ◽  
Polyelectrolyte Complex ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
Kinetics Of ◽  
Ray Scattering

We have directly observed the <i>in situ</i> self-assembly kinetics of polyelectrolyte complex (PEC) micelles by synchrotron time-resolved small-angle X-ray scattering, equipped with a stopped-flow device that provides millisecond temporal resolution. This work has elucidated one general kinetic pathway for the process of PEC micelle formation, which provides useful physical insights for increasing our fundamental understanding of complexation and self-assembly dynamics driven by electrostatic interactions that occur on ultrafast timescales.

scholarly journals Effect of Na- and Organo-Modified Montmorillonite/Essential Oil Nanohybrids on the Kinetics of the In Situ Radical Polymerization of Styrene

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 474
Author(s):  
Ioannis S. Tsagkalias ◽  
Alexandra Loukidi ◽  
Stella Chatzimichailidou ◽  
Constantinos E. Salmas ◽  
Aris E. Giannakas ◽  
...  
Keyword(s):  
Essential Oil ◽  
Radical Polymerization ◽  
Food Packaging ◽  
In Situ Polymerization ◽  
Average Molecular Weight ◽  
Monomer Conversion ◽  
Hydroxyl Groups ◽  
Modified Montmorillonite ◽  
Kinetics Of

The great concern about the use of hazardous additives in food packaging materials has shown the way to new bio-based materials, such as nanoclays incorporating bioactive essential oils (EO). One of the still unresolved issues is the proper incorporation of these materials into a polymeric matrix. The in situ polymerization seems to be a promising technique, not requiring high temperatures or toxic solvents. Therefore, in this study, the bulk radical polymerization of styrene was investigated in the presence of sodium montmorillonite (NaMMT) and organo-modified montmorillonite (orgMMT) including thyme (TO), oregano (OO), and basil (BO) essential oil. It was found that the hydroxyl groups present in the main ingredients of TO and OO may participate in side retardation reactions leading to lower polymerization rates (measured gravimetrically by the variation of monomer conversion with time) accompanied by higher polymer average molecular weight (measured via GPC). The use of BO did not seem to affect significantly the polymerization kinetics and polymer MWD. These results were verified from independent experiments using model compounds, thymol, carvacrol and estragol instead of the clays. Partially intercalated structures were revealed from XRD scans. The glass transition temperature (from DSC) and the thermal stability (from TGA) of the nanocomposites formed were slightly increased from 95 to 98 °C and from 435 to 445 °C, respectively. Finally, better dispersion was observed when orgMMT was added instead of NaMMT.

Kinetics of the reactive spreading of molten aluminum on ceramic surfaces

1995 ◽  
Vol 10 (3) ◽  
pp. 640-650 ◽  
Author(s):  
Douglas A. Weirauch ◽  
Willy M. Balaba ◽  
Anthony J. Perrotta
Keyword(s):  
Molten Aluminum ◽  
Unit Area ◽  
Triple Line ◽  
Temperature Analysis ◽  
Experimental Conditions ◽  
Ceramic Surfaces ◽  
Main Effect ◽  
Kinetics Of ◽  
Rate Of Movement

The spreading kinetics of molten aluminum on ceramic surfaces bearing reactive coatings has been studied through the direct observation of sessile drops, either formed in situ or emplaced at temperature. Analysis of videotapes permitted the assessment of the rate of advance of rapidly spreading droplets. Experimental conditions in this study were chosen to avoid the severe retarding effect of the aluminum oxide film which is typically encountered in aluminum wetting experiments. A variety of reactive coating systems were examined (B, Cu, Ni, Ti, and Ti + B), and the effect of coating amount was assessed. Based upon the experiments of this study, the main effect of the coatings is to drive spreading due to strong exothermic interfacial reactions. The intensity of the interfacial reaction causes the change in free energy per unit area of interface to dominate the rate of movement of the triple line.

scholarly journals Radiolytic synthesis of gold nanoparticles in HEMA-based hydrogels: Potentialities for imaging nanocomposites

Nukleonika ◽  
2021 ◽  
Vol 66 (4) ◽  
pp. 165-177
Author(s):  
Katsiaryna Dziarabina ◽  
Uliana Pinaeva ◽  
Sławomir Kadłubowski ◽  
Piotr Ulański ◽  
Xavier Coqueret
Keyword(s):  
Gold Nanoparticles ◽  
Monomer Conversion ◽  
Thermomechanical Properties ◽  
Temperature Sensitive ◽  
Trimethylammonium Chloride ◽  
Stimuli Responsive ◽  
Monomer Composition ◽  
Swelling Characteristics ◽  
High Degree ◽  
Radiolytic Synthesis

Abstract This article reports on the radiolytic synthesis of nanocomposites containing gold nanoparticles (AuNPs) within two types of hydrogels based on 2-hydroxyethyl methacrylate (HEMA): (i) plain networks with various contents in ethylene glycol dimethacrylate (EGDMA), as a cross-linker and (ii) stimuli-responsive (SR) networks prepared from these monomers copolymerized with [2-(methacryloyloxy)ethyl]trimethylammonium chloride (MADQUAT) to confer pH-switchable swelling. Hydrogels were prepared by photopolymerization with well-defined composition and a high degree of monomer conversion using two experimental procedures, as xerogels or in aqueous solution. Besides MADQUAT, acrylic acid (AA) or N-isopropylacrylamide have been tested as copolymers, yielding pHor temperature-sensitive hydrogels, respectively. Isothermal swelling in water was affected by monomer composition. Electron beam (EB) irradiation at doses up to 100 kGy of poly(HEMA) xerogels and water-swollen networks prepared with 0.5 wt% of EGDMA had a moderate impact on swelling characteristics and thermomechanical properties of the plain materials, whereas small amounts of extractables were formed. Poly(HEMA)-based nanocomposites containing AuNPs were successfully obtained by EB irradiation of samples swollen by aqueous solutions of Au(III). The effects of dose and cross-linking density on the formation of AuNPs were monitored by UV-visible spectroscopy. Irradiation at well-defined temperatures of the Au(III)-loaded SR hydrogels induced the formation of nanoparticles with size-dependent features, whereas the efficiency of Au(III) reduction at 10 kGy was not significantly affected by the network structure. EB-induced reduction of Au(III) in poly(HEMA) hydrogels using a lead mask to generate well-defined patterns yielded coloured and long-lasting images in the zones where the nanocomposite was formed.

Application of online infrared spectroscopy to study the kinetics of precipitation polymerization of acrylic acid in supercritical carbon dioxide

2016 ◽  
Vol 1 (4) ◽  
pp. 372-378 ◽  
Author(s):  
Jean-Noël Ollagnier ◽  
Thierry Tassaing ◽  
Simon Harrisson ◽  
Mathias Destarac
Keyword(s):  
Carbon Dioxide ◽  
Infrared Spectroscopy ◽  
Supercritical Carbon Dioxide ◽  
Acrylic Acid ◽  
Ftir Spectroscopy ◽  
Precipitation Polymerization ◽  
Kinetics Of Precipitation ◽  
Kinetics Of ◽  
Supercritical Carbon

The kinetics of precipitation polymerization of acrylic acid in supercritical CO2 is monitored by in situ FTIR spectroscopy.

scholarly journals Preparation of Poly (Allylthiourea-Co-Acrylic Acid) Derived Carbon Materials and Their Applications in Wastewater Treatment

Molecules ◽  
2019 ◽  
Vol 24 (5) ◽  
pp. 957 ◽  
Author(s):  
Limei Liang ◽  
Chengpeng Li ◽  
Tingting Hou ◽  
Zhiying Zhong ◽  
Dongchu Chen ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Acrylic Acid ◽  
Carbon Materials ◽  
Sewage Treatment ◽  
Experimental Conditions ◽  
Removal Capacity ◽  
Carbon Monolith ◽  
Paraffin Oil ◽  
Pseudo Second Order

Functional carbon materials have been developed and applied in various sewage treatment applications in recent years. This article reports the fabrication, characterization, and application of a new kind of poly (allylthiourea-co-acrylic acid) (PAT–PAC) hydrogel-based carbon monolith. The results indicated that the poly acrylic acid component can endow the PAT–PAC hydrogel with an increased swelling ratio and enhanced thermal stability. During the carbonization process, O–H, N–H, C=N, and –COO– groups, etc. were found to be partly decomposed, leading to the conjugated C=C double bonds produced and the clear red shift of C=O bonds. Particularly, it was found that this shift was accelerated under higher carbonization temperature, which ultimately resulted in the complex conjugated C=C network with oxygen, nitrogen, and sulfur atoms doped in-situ. The as-obtained carbon monoliths showed good removal capacity for Ni(II) ions, organic solvents, and dyes, respectively. Further analysis indicated that the Ni(II) ion adsorption process could be well described by pseudo-second-order and Freundlich models under our experimental conditions, respectively. The adsorption capacity for Ni(II) ions and paraffin oil was as high as 557 mg/g and 1.75 g/g, respectively. More importantly, the as-obtained carbon monoliths can be recycled and reused for Ni(II) ions, acetone, and paraffin oil removal. In conclusion, the proposed PAT–PAC-based carbonaceous monoliths are superior adsorbents for wastewater treatment.

Kinetics of the Fully Inhibited Thermal Decomposition of Bistrifluoromethyl Peroxide, CF3OOCF3

1975 ◽  
Vol 53 (10) ◽  
pp. 1442-1448 ◽  
Author(s):  
Bernard Descamps ◽  
Wendell Forst
Keyword(s):  
Thermal Decomposition ◽  
Gas Phase ◽  
Rate Constant ◽  
Chromatographic Analysis ◽  
Static Method ◽  
Experimental Conditions ◽  
Experimental Expression ◽  
Kinetics Of ◽  
Rate Of Accumulation

The pyrolyosis of CF3OOCF3 (BTMP) was studied in the gas phase from 5 to 100 Torr BTMP pressure and between 197 and 244 °C in a clean nickel reactor by the static method. CF3O radicals, due to the initial split[Formula: see text] were scavenged by SO3F radicals produced in situ by the thermal decomposition of their dimer S2O6F2. Under these conditions, CF3OOSO2F is the only product of BTMP pyrolysis, as shown by gas chromatographic analysis. Thus the BTMP pyrolysis becomes fully inhibited and the rate of accumulation of CF3OOSO2F is a measure of k1. The rate constant k1 turns out to be pressure-insensitive under the experimental conditions, from which it is inferred that k1 is actually k1∞, the limiting high-pressure unimolecular rate constant for reaction 1. Its temperature dependence yields the result[Formula: see text]This result is compared with other values of the O—O bond dissociation energy in BTMP. The experimental expression for k1 ∞ is used to construct the pressure falloff of k1 following the procedure of Forst. The calculation confirms that falloff begins only below 10 Torr.

scholarly journals RAFT Copolymerization of Styrene and Maleic Anhydride with Addition of Ascorbic Acid at Ambient Temperature

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Juxiang Luo ◽  
Deshu Cheng ◽  
Mingchun Li ◽  
Meihua Xin ◽  
Weifu Sun ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Ascorbic Acid ◽  
Maleic Anhydride ◽  
Ambient Temperature ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Monomer Conversion ◽  
Experimental Conditions ◽  
Monomer Composition ◽  
Novel Method

A novel method for RAFT copolymerization of styrene (St) and maleic anhydride (MAh) at ambient temperature using ascorbic acid (Asc) as an initiator is reported. Various experimental conditions including reaction component, monomer composition, the amount of Asc, and temperature were investigated in terms of monomer conversion, molecular weight, and molecular weight distribution. In this system, the copolymer of styrene/maleic anhydride (SMA) with well-regulated molecular weight and low molecular weight distribution (Mw/Mn=1.30) was obtained, and the conversion of monomer was 70.4% after 12 hours at 25°C. The NMR spectra demonstrated that the copolymer synthesized possesses a strictly alternating structure. Furthermore, the proposed mechanism adapted to the RAFT copolymerization of St and MAh initiated by Asc at ambient temperature is presented. Using this new methodology, it is possible to achieve well-defined SMA under mild conditions by RAFT copolymerization.

Sign in / Sign up

Export Citation Format

Share Document