scholarly journals Concerning Synthesis of New Biobased Polycarbonates with Curcumin in Replacement of Bisphenol A and Recycled Diphenyl Carbonate as Example of Circular Economy

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 361
Author(s):  
Vincenzo De Leo ◽  
Michele Casiello ◽  
Giuseppe Deluca ◽  
Pietro Cotugno ◽  
Lucia Catucci ◽  
...  
Keyword(s):  
Bisphenol A ◽  
Gel Permeation Chromatography ◽  
Second Step ◽  
Chemical Recycling ◽  
Diphenyl Carbonate ◽  
Molecular Weights ◽  
Synthetic Strategy ◽  
Biobased Polymers ◽  
Natural Polyphenol ◽  
Pharmaceutical Properties

Curcumin (CM) is a natural polyphenol well-known for its antioxidant and pharmaceutical properties, that can represent a renewable alternative to bisphenol A (BPA) for the synthesis of bio-based polycarbonates (PC). In the presented strategy, preparation of the CM-based PC was coupled with chemical recycling of the fossil-based BPA polycarbonate (BPA-PC) conducting a two-steps trans-polymerization that replaces BPA monomer with CM or its tetrahydrogenated colorless product (THCM). In the first step of synthetic strategy, depolymerization of commercial BPA-PC was carried out with phenol as nucleophile, according to our previous procedure based on zinc derivatives and ionic liquids as catalysts, thus producing quantitatively diphenyl carbonate (DPC) e BPA. In the second step, DPC underwent a melt transesterification with CM or THCM monomers affording the corresponding bio-based polycarbonates, CM-PC and THCM-PC, respectively. THCM was prepared by reducing natural bis-phenol with cyclohexene as a hydrogen donor and characterized by 1H-NMR and MS techniques. Polymerization reactions were monitored by infrared spectroscopy and average molecular weights and dispersity of the two biobased polymers THCM-PC and CM-PC were determined by means of gel permeation chromatography (GPC). Optical properties of the prepared polymers were also measured.

Preparation and Characterization of Bisphenol a Polycarbonate Facilitated by Supercritical Impinging Stream

2014 ◽  
Vol 875-877 ◽  
pp. 101-105
Author(s):  
Yang Xiao ◽  
Ai Qing Zhang
Keyword(s):  
Mass Transfer ◽  
Bisphenol A ◽  
Gel Permeation Chromatography ◽  
Diphenyl Carbonate ◽  
Infrared Spectrophotometry ◽  
Bisphenol A Polycarbonate ◽  
Synthetic Process ◽  
Ft Ir ◽  
C Nmr

Based on the supercritical impinging stream technique, a novel synthetic process for preparing aromatic polycarbonate (PC) by transesterification between bisphenol-A (BPA) and diphenyl carbonate (DPC) was developed. Supercritical carbon dioxide (ScCO2) is an excellent plasticizing agent and a good solvent for phenol, the by-product of the reaction. Impinging stream can markedly enhance heat and mass transfer, especially mass transfer between phases. In this process, phenol formed from the reaction was dissolved and diffused into ScCO2 phase and the transfer process were accelerated through the impingement of two flows. The structure of the product was characterized by Fourier transform infrared spectrophotometry (FT-IR), 1H-nuclear magnetic resonance (NMR) and 13C-NMR measurements. Thermal analysis was measured by a differential scanning calorimeter (DSC). The PC molecular weight (MW) was determined by gel permeation chromatography (GPC) and can reach up to 4.28×104 g/mol.

scholarly journals Synthesis and In Vitro Antimicrobial Evaluation of Photoactive Multi—Block Chalcone Conjugate Phthalimide and 1,8-Naphthalimide Novolacs

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1859
Author(s):  
Periyan Durairaju ◽  
Chinnasamy Umarani ◽  
Govindasami Periyasami ◽  
Perumberkandigai Adikesavan Vivekanand ◽  
Mostafizur Rahaman
Keyword(s):  
Spectroscopic Analysis ◽  
Photophysical Properties ◽  
Gel Permeation Chromatography ◽  
13C Nmr Spectroscopy ◽  
Antimicrobial Activities ◽  
Microbial Activities ◽  
E Coli ◽  
Molecular Weights ◽  
Antimicrobial Evaluation

Herein we report new multiblock chalcone conjugate phthalimide and naphthalimide functionalized copolymers with a topologically novel architecture synthesis using nucleophilic substitution and polycondensation methodology. The structures of the synthesized novolacs were elucidated on the basis of their spectroscopic analysis including FTIR, 1H NMR, and 13C NMR spectroscopy. Further, the number-average and weight-average molecular weights of the novolac polymers were determined by gel permeation chromatography (GPC). We examined the solubility of the synthesized polymers in various organic solvents including CHCl3, CH3CN, THF, H2O, CH3OH, DMSO, and DMF and found they are insoluble in both methanol and water. The novolac polymers were evaluated for their photophysical properties and microbial activities. The investigation of the antimicrobial activities of these polymers reveals significant antimicrobial activity against the pathogens E. coli, S. aureus, C. albicans, and A. niger.

Probing the molecular weights of sweetgum and pine kraft lignin fractions

TAPPI Journal ◽  
2021 ◽  
Vol 20 (6) ◽  
pp. 381-391
Author(s):  
JULIANA M. JARDIM ◽  
PETER W. HART ◽  
LUCIAN LUCIA ◽  
HASAN JAMEEL
Keyword(s):  
Molecular Weight ◽  
Black Liquor ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Systematic Investigation ◽  
Kraft Pulping ◽  
Molecular Weights ◽  
Lignin Recovery ◽  
Lignin Reactivity ◽  
Kinetics Of

The present investigation undertook a systematic investigation of the molecular weight (MW) of kraft lignins throughout the pulping process to establish a correlation between MW and lignin recovery at different extents of the kraft pulping process. The evaluation of MW is crucial for lignin characterization and utilization, since it is known to influence the kinetics of lignin reactivity and its resultant physicochemical properties. Sweetgum and pine lignins precipitated from black liquor at different pHs (9.5 and 2.5) and different extents of kraft pulping (30–150 min) were the subject of this effort. Gel permeation chromatography (GPC) was used to deter- mine the number average molecular weight (Mn), mass average molecular weight (Mw), and polydispersity of the lignin samples. It was shown that the MW of lignins from both feedstocks follow gel degradation theory; that is, at the onset of the kraft pulping process low molecular weightlignins were obtained, and as pulping progressed, the molecular weight peaked and subsequently decreased. An important finding was that acetobromination was shown to be a more effective derivatization technique for carbohydrates containing lignins than acetylation, the technique typically used for derivatization of lignin.

Synthesis and characterization of novel methacrylate copolymers having pendant piperonyl group: monomer reactivity ratio, thermal degradation kinetics, and biological activity

2021 ◽  
Vol 29 (9_suppl) ◽  
pp. S1432-S1445
Author(s):  
Ibrahim Erol ◽  
Bayram Gencer ◽  
Zeki Gurler
Keyword(s):  
Biological Activity ◽  
Degradation Kinetics ◽  
Gel Permeation Chromatography ◽  
Reactivity Ratio ◽  
Thermal Degradation Kinetics ◽  
Scanning Calorimetry ◽  
Molecular Weights ◽  
Monomer Reactivity Ratio ◽  
Bacteria And Fungi ◽  
Photo Stability

In this study, 2-{[(2H-1,3-benzodioxol-5-yl)methyl]amino}-2-oxoethyl 2-methylprop-2-enoate (BMAOME) monomer was synthesized, and copolymers were prepared with glycidyl methacrylate (GMA). Structural characterizations of the compounds were performed using FTIR, 1H-, and 13C-NMR techniques. Monomer reactivity ratio values were calculated by Finemann–Ross (FR) and Kelen–Tudos (KT) methods. The Tg value of the polymers was determined by differential scanning calorimetry (DSC) and their thermal stability was determined by thermogravimetric analysis (TGA). The molecular weights (w and n) and polydispersity index of the polymers were determined by gel permeation chromatography. The Ea value of thermal decomposition was determined by using the Ozawa and Kissinger methods. The photo-stability of the copolymers was investigated. Furthermore, the photo-stability of the copolymers and the biological activity of polymers against different types of bacteria and fungi were investigated.

scholarly journals Tailoring π-conjugation and vibrational modes to steer on-surface synthesis of pentalene-bridged ladder polymers

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Bruno de la Torre ◽  
Adam Matěj ◽  
Ana Sánchez-Grande ◽  
Borja Cirera ◽  
Benjamin Mallada ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Materials Science ◽  
Second Step ◽  
Vibrational Modes ◽  
Force Microscopy ◽  
Synthetic Strategy ◽  
Atomic Force ◽  
Structures And Properties ◽  
Ladder Polymers ◽  
Ladder Polymer

Abstract The development of synthetic strategies to engineer π-conjugated polymers is of paramount importance in modern chemistry and materials science. Here we introduce a synthetic protocol based on the search for specific vibrational modes through an appropriate tailoring of the π-conjugation of the precursors, in order to increase the attempt frequency of a chemical reaction. First, we design a 1D π-conjugated polymer on Au(111), which is based on bisanthene monomers linked by cumulene bridges that tune specific vibrational modes. In a second step, upon further annealing, such vibrational modes steer the twofold cyclization reaction between adjacent bisanthene moieties, which gives rise to a long pentalene-bridged conjugated ladder polymer featuring a low bandgap. In addition, high resolution atomic force microscopy allows us to identify by atomistic insights the resonance form of the polymer, thus confirming the validity of the Glidewell and Lloyd´s rules for aromaticity. This on-surface synthetic strategy may stimulate exploiting previously precluded reactions towards π-conjugated polymers with specific structures and properties.

Using a natural chlorite as catalyst in chemical recycling of waste plastics: Hydrolytic depolymerization of poly-[bisphenol A carbonate] promoted by clinochlore

2021 ◽  
Vol 120 ◽  
pp. 642-649
Author(s):  
Eugenio Quaranta ◽  
Ernesto Mesto ◽  
Maria Lacalamita ◽  
Cosimino Malitesta ◽  
Elisabetta Mazzotta ◽  
...  
Keyword(s):  
Bisphenol A ◽  
Chemical Recycling ◽  
Waste Plastics ◽  
Hydrolytic Depolymerization

scholarly journals Cellulase-Assisted Extraction, Characterization, and Bioactivity against Rheumatoid Arthritis of Astragalus Polysaccharides

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Ling Cao ◽  
Mi Yu ◽  
Chonghui Wang ◽  
Yunhui Bao ◽  
Minghui Zhang ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
High Performance ◽  
Biological Activities ◽  
Gel Permeation Chromatography ◽  
Type Ii Collagen ◽  
Therapeutic Effects ◽  
Molecular Weights ◽  
Assisted Extraction ◽  
Synovial Membranes ◽  
Cellulose Column

This study investigated the effect of cellulase on the isolation of crude Astragalus polysaccharide (APS), analyzed the monosaccharide component of deproteinized APS, detected the molecular weights of purified APS, and examined the biological activities and the preliminary mechanism against rheumatoid arthritis (RA). Compared with water extraction method, cellulase-assisted extraction increased the yield of crude APS to 154% and polysaccharide contents to 121%. Crude APS was then purified by ethanol precipitation, Sevag deproteinization, and high-performance liquid chromatography (HPLC) analysis; monosaccharide contents of APS were different after cellulase-assisted method, especially galacturonic acid content which significantly increased. DEAE-52 cellulose column chromatography isolated three polysaccharide fractions, including a neutral polysaccharide (APS-water) and two acidic polysaccharides (APS-NaCl1 and APS-NaCl2). Using high-performance gel permeation chromatography (HPGPC), the molecular weights of APS-water, APS-NaCl1, and APS-NaCl2 were identified as 67.7 kDa, 234.1 kDa, and 189.4 kDa, respectively. Then their therapeutic effects and possible mechanism against RA were explored using type II collagen-induced arthritis (CIA) rat model. APS could significantly reduce paw swelling, serum concentration of IL-1β and TNF-α, and the expression levels of NF-κB-p65 and IκBα in synovial membranes in CIA rats. Our study indicated that cellulase significantly increases the yield and polysaccharide contents of crude APS, improves the product quality, and preserves the biological features against RA in CIA rats.

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