The copolymer of polyvinyl acetate containing lignin-vinyl acetate monomer: synthesis and characterization

Publication date: Available online 15 December 2019Source: European Polymer JournalAuthor(s): Nana Zhang, Shoujuan Wang, Magdi E. Gibril, Fangong KongAbstractApplication of the lignin-based monomer in polymers synthesis will reducing the use of petrochemical-based monomers, enhance the polymer/copolymers properties, and disposing lignin in a profitable way. Accordingly, in this work, the lignin-vinyl acetate monomer (LVAc) and its copolymers were synthesized successfully. To obtain the LVAc, firstly, lignin was activated with the amine using diethylenetriamine (DETA) and then followed by the grafting with chlorovinyl acetate (CVAc) in alkali medium. The optimal conditions of the preparation the LVAc were determined with the 40 °C, for 6 hours, and at pH 9. The copolymers were synthesized through a suspension-copolymerization of the LVAc with vinyl acetate (VAc) monomers, which was carried out at 60 °C for 3 hours in the presence of Benzoyl peroxide (initiator). The characterization of the LVAc and its copolymers were done by different methods such as elemental analysis, Proton Nuclear Magnetic Resonance (1HNMR), X-ray photoelectron spectroscopy (XPS), Gel permeation chromatography (GPC), Thermogravimetric analysis (TGA), Differential scanning calorimetric (DSC), and Fourier transform infrared spectroscopy (FTIR). GPC analysis showed that the molecular weight (Mw) for the copolymers was higher with more 10,000 g/mol compared to the PVAc. Worth mention the increasing of...
Source: European Polymer Journal - Category: Chemistry Source Type: research

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Publication date: Available online 18 January 2020Source: Carbohydrate PolymersAuthor(s): Dimitrios G. Trikkaliotis, Achilleas K. Christoforidis, Athanasios C. Mitropoulos, George Z. KyzasAbstractA novel adsorbent material composed of chitosan (Cs), polyvinyl alcohol (PVA) and polyethylene glycol (PEG) was prepared in hydrogel bead form to efficiently remove copper ions from aqueous solutions. The properties of the composite were characterized by scanning electronic microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM) and Fourier transform infrared spectroscop...
Source: Carbohydrate Polymers - Category: Biomedical Science Source Type: research
This study provides strong evidence that following a healthy lifestyle can substantially extend the years a person lives disease-free." Commentary on Recent Evidence for Cognitive Decline to Precede Amyloid Aggregation in Alzheimer's Disease https://www.fightaging.org/archives/2020/01/commentary-on-recent-evidence-for-cognitive-decline-to-precede-amyloid-aggregation-in-alzheimers-disease/ I can't say that I think the data presented in the research noted here merits quite the degree of the attention that it has been given in the popular science press. It is interesting, but not compelling if its role...
Source: Fight Aging! - Category: Research Authors: Tags: Newsletters Source Type: blogs
Publication date: Available online 18 January 2020Source: Wound MedicineAuthor(s): Sara S. Abou Zekry, Ahmed Abdellatif, Hassan M.E. AzzazyAbstractHoney, pomegranate peel extract and bee venom, were used in combination with polyvinyl alcohol to develop a novel nanofibrous wound dressing. Methanolic pomegranate peel extract was prepared and mixed with either Manuka honey or lyophilized multiflora honey powder together with bee venom. The formulas were tested for their antibacterial activity, cytotoxicity, and wound healing activity in an excisional wound rat model. Scanning electron microscopy showed that lyophilized honey ...
Source: Wound Medicine - Category: General Medicine Source Type: research
Authors: Yildirim M, Kaplan M, Duzenli T, Tanoglu A, Kucukodaci Z, Onal Tastan Y, Cakir Guney B, Serindag Z Abstract Background: To investigate the protective efficacy of pentoxifylline through biochemical parameters and histopathological scores in a caerulein- and alcohol-induced experimental model of chronic pancreatitis in rats.Methods: A model of chronic pancreatitis with caerulein and alcohol was created in female rats of the genus Sprague Dawley. Pentoxifylline was administered in doses of 25 mg/kg (low dose) and 50 mg/kg (high dose) as a protective agent. Each group contained 8 animals. The gro...
Source: Scandinavian Journal of Gastroenterology - Category: Gastroenterology Tags: Scand J Gastroenterol Source Type: research
Conclusions: Deactivation in PCC and vmPFC to high-threat stimuli replicated previous work and shows promise for further study as a marker for AUD. Although prazosin did not affect brain activation in the regions of interest during the anticipatory anxiety task, subjective levels of anxiety and brain activation in vmPFC predicted treatment outcomes in individuals with AUD undergoing treatment with prazosin, highlighting individuals more likely to benefit from prazosin than others.
Source: NeuroImage: Clinical - Category: Radiology Source Type: research
This study investigated the feasibility of using pulsed electric fields (PEF) to develop biodegradable films from biopolymers (zein, chitosan) and biosynthetic polymers (poly(vinyl alcohol), polyethylene glycol). Various responses including the viscosity, loss modulus, particle size and polydispersity index of the dispersions were determined after PEF processing at various electric field strength (0.9–3.5 kV/cm), pulse frequency (50–300 Hz), and specific energy (80–650 kJ/kg). The structure-function relationship between the PEF processed colloidal dispersions, and the effect of PEF on the resulting ...
Source: Innovative Food Science and Emerging Technologies - Category: Food Science Source Type: research
Publication date: Available online 8 January 2020Source: Journal of Materials Research and TechnologyAuthor(s): Cláudio Faria Lopes Junior, Glauco Silva de Assis Machado, Patrícia Sousa Nilo Mendes, Priscila Sousa Nilo Mendes, José Augusto Oliveira Huguenin, Elivelton Alves Ferreira, Ladário da SilvaAbstractCopper and zinc alloys have applications in products exposed to harsh environments. Usually, these products have upon their surface a thin film of oxides, whose properties may change due to the exposure to air or aqueous solutions at room temperatures. This work analyzed copper and zinc alloy...
Source: Journal of Materials Research and Technology - Category: Materials Science Source Type: research
Abstract Jicama peroxidase (JP) was covalently immobilized onto functionalized multi-walled carbon nanotube (MWCNT) Buckypaper/Polyvinyl alcohol (BP/PVA) membrane and employed for degradation of methylene blue dye. The parameters of the isotherm and kinetic models are estimating using ant colony optimization (ACO), which do not meddle the non-linearity form of the respective models. The proposed inverse modeling through ACO optimization was implemented, and the parameters were evaluated to minimize the non-linear error functions. The adsorption equilibrium was best described by the Freundlich isotherm model, where...
Source: Environmental Pollution - Category: Environmental Health Authors: Tags: Environ Pollut Source Type: research
In this study, a biocomposite of chitosan/poly vinyl alcohol/activated carbon was synthesized and used for hexavalent chrome removal from aqueous solution. The synthesized adsorbent was characterized by Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FTIR) analysis. The effect of important variables such as pH, concentration, contact time, temperature, and adsorbent dosage was investigated. The value of pHPZC for the adsorbent was evaluated at 4.9. Results showed that adsorption of chrome onto the adsorbent follows the Langmuir isotherm model and has a pseudo-second-order kinetic model. The maximum capac...
Source: International Journal of Biological Macromolecules - Category: Biochemistry Authors: Tags: Int J Biol Macromol Source Type: research
Publication date: Available online 7 January 2020Source: Reactive and Functional PolymersAuthor(s): Katja Vasić, Željko Knez, Elizaveta A. Konstantinova, Alexander I. Kokorin, Sašo Gyergyek, Maja LeitgebAbstractMNPs were synthesized with co-precipitation of ferrous and ferric ions. Carboxymethyl dextran (CMD) was covalently bound to MNPs and the influence of different concentrations on characteristics of CMD coated magnetic nanoparticles (CMD-MNPs) was studied. Different concentrations of CMD were applied into synthesis process. The surface morphology of CMD-MNPs was monitored by scanning and transmission electron...
Source: Reactive and Functional Polymers - Category: Chemistry Source Type: research
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