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.

scholarly journals Morphology and crystallization kinetics of Rubber-modified Nylon 6 Prepared by Anionic In-situ Polymerization

2020 ◽  
Vol 27 (1) ◽  
pp. 204-215
Author(s):  
Hongkai Zhao ◽  
Dengchao Zhang ◽  
Yingshuang Li
Keyword(s):  
Crystallization Kinetics ◽  
In Situ Polymerization ◽  
Good Description ◽  
Nylon 6 ◽  
Avrami Equation ◽  
Infrared Analysis ◽  
Chain Segment ◽  
The Impact ◽  
Kinetics Of

AbstractIn this work, we modified nylon 6 with liquid rubber by in-situ polymerization. The infrared analysis suggested that HDI urea diketone is successfully blocked by caprolactam after grafting on hydroxyl of HTPB, and the rubber-modified nylon copolymer is generated by the anionic polymerization. The impact section analysis indicated the rubber-modified nylon 6 resin exhibited an alpha crystal form.With an increase in the rubber content, nylon 6 was more likely to generate stable α crystal. Avrami equation was a good description of the non-isothermal crystallization kinetics of nylon-6 and rubber-modified nylon-6 resin. Moreover, it is found that the initial crystallization temperature of nylon-6 chain segment decreased due to the flexible rubber chain segment. n value of rubber-modified nylon-6 indicated that its growth was the coexistence of two-dimensional discoid and three-dimensional spherulite growth. Finally, the addition of the rubber accelerated the crystallization rate of nylon 6.

Preparation and Properties of the Polystyrene/Alumina Nanocomposites

2012 ◽  
Vol 557-559 ◽  
pp. 519-522
Author(s):  
Xu Man Wang ◽  
Cai Ning Zhang
Keyword(s):  
Molecular Weight ◽  
Thermal Resistance ◽  
Coupling Agent ◽  
Silane Coupling Agent ◽  
In Situ Polymerization ◽  
Average Molecular Weight ◽  
Experimental Results ◽  
Solvent Resistance ◽  
Silane Coupling

Silane coupling agent KH-570 was applied to modify the surface capability of the alumina (Al2O3). The modified Al2O3were dispersed in styrene. The in-situ polymerization was used to prepare the polystyrene/alumina (PS/Al2O3) composites, in which azodiisobutyronitrile (AIBN) was used as initiator. FTIR, DSC and TG were applied to characterize the prepared composites. The solvent resistance, thermal resistance of the composites and the average molecular weight of PS in PS/Al2O3nanocomposites were studied. The experimental results demonstrated that the solvent resistance of PS/Al2O3nanocomposites was improved by the adding of Al2O3nanoparticles. The thermal resistance of the composites increased with the increasing of the Al2O3content. Meanwhile, the molecular weight of PS in the composites increased with the increasing of the Al2O3content.

In situ polymerization of supramolecular nanorods assembled from polymerizable perylene bisimide

2017 ◽  
Vol 8 (30) ◽  
pp. 4422-4427 ◽  
Author(s):  
Yan Sun ◽  
Zhibo Li
Keyword(s):  
Free Radical ◽  
Radical Polymerization ◽  
In Situ Polymerization ◽  
Free Radical Polymerization ◽  
Perylene Bisimide

Dimethacryl amide functionalized perylene bisimide monomer was synthesized, in-situ free radical polymerization was then performed in the organized state to maintain the assembly structures.

Preparation of ZnO/PANI Nanocomposite and Study on its Photocatalytic Properties

2013 ◽  
Vol 716 ◽  
pp. 368-372
Author(s):  
Hui Xu ◽  
Jian Wei Xing
Keyword(s):  
Charge Separation ◽  
In Situ Polymerization ◽  
Blue Dye ◽  
Methylene Blue Dye ◽  
Aniline Monomer ◽  
First Order ◽  
Photocatalytic Activities ◽  
Recombination Centers ◽  
Kinetics Of

Polyaniline (PANI)/zinc oxide (ZnO) nanocomposites have been synthesized by in-situ polymerization of aniline monomer with ZnO nanomaterials. The PANI/ZnO nanocomposites were used as photocatalyst in the photodegradation of methylene blue dye (MB) molecules in aqueous solution. The results showed that PANI/ZnO nanocomposite greatly enhanced photocatalytic activities compared with pristine polyaniline might due to high photoexcited electronhole pairs charge separation. The photocatalytic activities of PANI/ZnO nanocomposites increased with increasing ZnO content, however, further increasing ZnO content over 50% induced the formation of more agglomerates, which could act as recombination centers of photoexcited electronhole pairs, leading to decreased photocatalytic activity. The kinetics of photodegradation of MB dye using PANI/ZnO(ZnO content 50 % ) nanocomposites photocatalyst was found to be of the first order.

Preparation and Properties of Oxidized Coal/Polyaniline Composite Material

2011 ◽  
Vol 306-307 ◽  
pp. 220-223
Author(s):  
Xiao Ping Fan ◽  
An Ning Zhou
Keyword(s):  
Composite Material ◽  
In Situ Polymerization ◽  
Polymer Network ◽  
Interpenetrating Polymer Network ◽  
Hydroxyl Groups ◽  
Oxidized Coal ◽  
Pani Composite ◽  
Maximum Conductivity ◽  
Hydrolysis Of

Semi-interpenetrating polymer network of coal/polyaniline (PANI) composite material were prepared by in situ polymerization. Raw coal was oxidized in different conditions by H2O2 and HNO3, respectively. The total acidic groups analysis, Fourier transform infrared (FTIR) spectrum, and conductivity test of the raw coal and the oxidized coal/PANI composite material were conducted. The results showed that the increases of the carboxyl groups and the hydroxyl groups were mainly attributed to the hydrolysis of the weak ether link and the transform from the carboxylate to carboxylic acid. These increases were benefit to the reaction of coal and PANI, and consequently enhanced the conductivity of the composite material. The maximum conductivity of oxidized coal/PANI reached 4.72×10‑1 S/cm.

New Low Toxic Water-Soluble Monomers for Gelcasting of Ceramic Powders

2010 ◽  
Vol 62 ◽  
pp. 163-168 ◽  
Author(s):  
Mikolaj Szafran ◽  
Agnieszka Szudarska ◽  
Paulina Bednarek
Keyword(s):  
In Situ Polymerization ◽  
Polymer Network ◽  
Water Soluble ◽  
Cross Linking ◽  
Alumina Powder ◽  
Hydroxyl Groups ◽  
Ceramic Powders ◽  
Ceramic Slurry ◽  
Low Toxic

In this paper the two new low toxic water-soluble monomers: glycerol monoacrylate and 3-O-acrylic-D-glucose are introduced and their application in gelcasting of alumina powder is reported, in comparison with 2-hydroxyethyl acrylate, the commercial monomer. Both synthesized substances do not need an addition of cross-linking agent to the ceramic slurry, because hydrogen bonds can be formed in the polymer network, owing to the presence of two or more hydroxyl groups in their molecules, unlike in the case of 2-hydroxyethyl acrylate. Rheological behavior of alumina gelcasting suspensions containing these monomers has been studied, as well as the characteristics of raw and sintered elements formed from these slurries by initializing an in situ polymerization.

scholarly journals Role of Zingiber Officinale Essential Oil- Chitosan Based Biopolymer Film For Bioactive Packaging

2021 ◽  
Author(s):  
Sawsan A. Al-Hilifi ◽  
Rawdah M. Al-Ali
Keyword(s):  
Essential Oil ◽  
Food Packaging ◽  
Fourier Transforms ◽  
Zingiber Officinale ◽  
Differential Scanning Calorimetric ◽  
Hydroxyl Groups ◽  
X Ray Diffraction ◽  
Ft Ir ◽  
Biopolymer Film

Abstract The recent interest in bio-packing at field of food become trending in the development of antimicrobial coatings. The focus of this study was to assess the potential application of zingiber officinale essential oil (GEO) in chitosan films (CHf). The data indicated that there were significant differences(p < 0.05) in the chemical composition of the samples.Forty-seven active compounds of the essential oil were identified from the rhizomes of ginger, which were identified byGC-MS. Fourier transforms infrared spectra (FT-IR) confirmed that an interaction between the hydroxyl groups of the phenolic compounds of the essential oil and the amide groups of polymer matrix. As shown the appearance of peaks at wavenumbers 1639cm-1 and 1558cm-1 Furthermore, X-ray diffraction results suggested a lower crystallintiyin CHf due to GEO effect. Differential Scanning Calorimetric (DSC) analysis revealed that CHf possessed high thermal stability, especially when different concentrations of GEO added. The bioactive CHf showed distinct activity against both positive and negative gram bacteria. They are Staphylococcus aurous, Bacillus subtillis, Streptococcus Sp. Escherichia coli, Salmonella Sp. Pseudomonas erugiosa. This results provides a comprehensive insight on the importance of films incorporated with EOs of interest in food packaging.

scholarly journals Model Discrimination for Hydrogen Peroxide Consumption towards γ-Alumina in Homogeneous Liquid and Heterogeneous Liquid-Liquid Systems

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1476
Author(s):  
Daniele Di Menno Di Bucchianico ◽  
Wander Y. Perez-Sena ◽  
Valeria Casson Moreno ◽  
Tapio Salmi ◽  
Sébastien Leveneur
Keyword(s):  
Hydrogen Peroxide ◽  
Ring Opening ◽  
Oxidation Mechanism ◽  
Liquid System ◽  
Side Reactions ◽  
Hydroxyl Groups ◽  
Homogeneous Liquid ◽  
Liquid Systems ◽  
Kinetics Of

The use of hydrogen peroxide as an oxidizing agent becomes increasingly important in chemistry. The example of vegetable oil epoxidation is an excellent illustration of the potential of such an agent. This reaction is traditionally performed by Prileschajew oxidation, i.e., by the in situ production of percarboxylic acids. Drawbacks of this approach are side reactions of ring-opening and thermal runaway reactions due to percarboxylic acid instability. One way to overcome this issue is the direct epoxidation by hydrogen peroxide by using γ-alumina. However, the reaction mechanism is not elucidated: does hydrogen peroxide decompose with alumina or oxidize the hydroxyl groups at the surface? The kinetics of hydrogen peroxide consumption with alumina in homogeneous liquid and heterogeneous liquid-liquid systems was investigated to reply to this question. Bayesian inference was used to determine the most probable models. The results obtained led us to conclude that the oxidation mechanism is the most credible for the heterogeneous liquid-liquid system.

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