3D porous Ti3C2 MXene/NiCo-MOF composites for enhanced lithium storage

To improve Li storage capacity and the structural stability of Ti3C2 MXene-based electrode materials for lithium-ion batteries (LIBs), a facile strategy is developed to construct three-dimensional (3D) hierarchical porous Ti3C2/bimetal-organic framework (NiCo-MOF) nanoarchitectures as anodes for high-performance LIBs. 2D Ti3C2 nanosheets are coupled with NiCo-MOF nanoflakes induced by hydrogen bonds to form 3D Ti3C2/NiCo-MOF composite films through vacuum-assisted filtration technology. The morphology and electrochemical properties of Ti3C2/NiCo-MOF are influenced by the mass ratio of MOF to Ti3C2. Owing to the interconnected porous structures with a high specific surface area, rapid charge transfer process, and Li+ di. © 2020 by the authors.National Natural Science Foundation of ChinaNational Natural Science Foundation of China [51702098]; National Key R&D Program of China [2016YFE0131200]; International Cooperation Project of Shanghai Municipal Science and Technology Committee [18520744400

Carboxymethylated and sulfated furcellaran from furcellaria lumbricalis and its immobilization on PLA scaffolds

This study involved the creation of highly porous PLA scaffolds through the porogen/leaching method, utilizing polyethylene glycol as a porogen with a 75% mass ratio. The outcome achieved a highly interconnected porous structure with a thickness of 25 μm. To activate the scaffold’s surface and improve its hydrophilicity, radiofrequency (RF) air plasma treatment was employed. Subsequently, furcellaran subjected to sulfation or carboxymethylation was deposited onto the RF plasma treated surfaces with the intention of improving bioactivity. Surface roughness and water wettability experienced enhancement following the surface modification. The incorporation of sulfate/carboxymethyl group (DS = 0.8; 0.3, respectively) is confirmed by elemental analysis and FT-IR. Successful functionalization of PLA scaffolds was validated by SEM and XPS analysis, showing changes in topography and increases in characteristic elements (N, S, Na) for sulfated (SF) and carboxymethylated (CMF). Cytocompatibility was evaluated by using mouse embryonic fibroblast cells (NIH/3T3).Ministry of Education, Youth, and Sports of the Czech Republi

Hidroksietil metakrilatın yaşayan radikal polimerleşmesi ve poli(dimetil siloksan) makrobaşlatıcı ile blok kopolimerleşmesi.

Hydrophilic poly(2-hydroxyethyl methacrylate), PHEMA, and hydrophobic poly(dimethyl siloxane), PDMS, segments containing copolymers have been widely used as a biomaterial. These amphiphilic copolymers also used as an emulsifying agent in polymer solutions and compatibilizer in polymer blends. In this case, solution polymerizations of HEMA by radiation, ATRP and RAFT methods were studied. The thermal degradation mechanism of PHEMA, which was prepared in aqueous solution by gamma radiation technique, was studied in detail. The DSC, TGA and Mass Spectroscopy analyses revealed that the degradation is linkage and depolymerization with a combination of monomer fragmentation. The ATRP of HEMA was performed with ethyl-2-bromoisobutyrate (EBriB) initiator and CuCl/bipyridine catalyst in MEK/1-propanol solvent mixture. Cu(II) complexes and PHEMA obtained via ATRP were characterized by UV-vis, FTIR and 1H-NMR analysis. The RAFT polymerization of HEMA with different [RAFT]/[AIBN] ratios were also investigated in three solvents (methyl ethylketone, ethyl acetate and toluene). The controlled polymerization of HEMA with the ratio of [RAFT]/ [AIBN]=18 at 80 oC in MEK and ethyl acetate, shows the first-order kinetic up to the nearly 40 % conversion Macroazoinitiator PDMS-MAI was synthesized from bifunctional PDMS and then copolymerized with MMA, EMA, HEMA and TMS-HEMA monomers Different characterization methods such as FTIR, 1H-NMR, solid state NMR, GPC, XPS, SEM, DSC, etc. have been used for the characterization of block copolymers. P(DMS-b-TMSHEMA) was converted to the P(DMS-b-HEMA) block copolymer by deprotection of TMS groups. The phase separated morphology was observed for the P(DMS-b-HEMA) copolymer, which was different from P(DMS-b-MMA) and P(DMS-b-EMA) copolymers.Ph.D. - Doctoral Progra

2-hidroeksietil akrilin polimerleştirilmesi ve karakterizasyonu

Poly(2-Hydroxyethyl acrylate), PHEA, is used as hydrophilic polymeric gels which have been studied because of its great importance for agricultural or biomedical applications. Biomedical applications of hydrogels include soft contact lenses, artificial corneas, soft tissue substitutes and burn dressings. In this study, it was aimed to synthesis the polymers with well-defined molecular weights, polydispersities and cahin topologies. Bulk, solution and atom transfer radical polymerization (ATRP) techniques at different temperatures were examined. The polymerization in bulk form was carried in vacuum and in open atmosphere. The polymerization curves showed autoacceleration mechanism. The polymers obtained were insoluable in most common solvents because of having high molecular weights and are crosslinked. So in order to overcome this problem, 2-hydroxyethyl acrylate was polymerized by solution and ATRP methods. The activation energy for bulk polymerization was found from Arrhenius plot. The polymer was characterized by FT-IR, DSC, TGA, 1H and 13C NMR techniques, Tensile tests were also examined for PHEA.M.S. - Master of Scienc

Sarıçam Odunu Unu, Fenol Formaldehit ve Melamin Formaldehit Reçinelerinden Odun Polimer Kompozitlerin Üretimi ve Karakterizasyonu

Giderek azalan odun kaynakları ve yeni kompozit teknolojilerinin gelişmesiyle odun polimer kompozitlerinin (OPK) üretimi önemli ölçüde artmıştır ve OP K’ler oduna göre daha üstün mekanik ve fiziksel özelli klere sahip olmaları nedeniyle geniş kullanım alanı bulmaktadırlar [1] . Fenol formaldehit (FF,Resol) ve melamin formaldehit (MF) reçineleri ile sarıçam odunu ( Pinus sylvestris ) ununun belli oranlarda karıştırılarak gelişmiş fiziksel ve mekanik özelliklere sahip ve aynı zamanda yanıcılığı azaltılmış OPK’lerin üretimi hedeflenmiştir. Çalışmada, bor fosfat (BPO 4 ) yanmayı geciktirici katkı maddesi, polidifenilmetan 4,4' - diizosiyanat, (PMDI) uyum sağlayıcı ajan olarak kompozitlerin üretiminde kullanılmıştır. Hidrotermal ve mikrodalga sentez yöntemleri birarada kullanılarak BPO 4 sentezlenmiş, FTIR spektroskopisi ve XRD ile karakterizasyonu yapılmıştır [2] . FF/MF reçinesiyle sarıçam odunu unu, PMDI ve BPO 4 içe ren kompozitlerin sıkıştırma ile kalıplama yöntemiyle hazırlanmasında karışım oranlarının belirlenerek kompozit üretim proses şartlarının optimizasyonu yapılmıştır. Kompozitlerin fiziksel özelliklerini belirlemede, kuru yoğunluk, su alma oranı ve kalınlık artış oranı testleri gerçekleştirilmiştir. Üretilen kompozitlerin eğilme direnci, üç noktadan eğilme testi ile incelenmiştir. Ayrıca BPO 4 katkılı OPK’lerin güç tutuşurluk ve yanma özellikleri sınırlayıcı oksijen indeksi (LOI testi) ve termogravimetrik anal iz (TGA) yöntemleriyle belirlenmiştir. İki farklı reçine (FF ve MF) kullanılarak üretilen OPK’lerin fiziksel, mekanik ve termal özellikleri karşılaştırılmıştır

Effect of LiClO4 Salt on Dielectric Properties of Acrylonitrile-Methyl Methacrylate and Acrylonitrile-Isobutyl Methacrylate Copolymers

Poly(acrylonitrile-co-isobutyl methacrylate), PAN-co-PIBMA, and poly(acrylonitrile-co-methyl methacrylate), PAN-co-MMA copolymers are synthesized by emulsion polymerization. The structural characterization is done by FTIR and H-1-NMR spectroscopy and thermal analyses are performed by thermogravimetric analysis (TGA). After various amounts of LiClO4 salt loading into copolymer films, the dielectric properties of these films at different temperatures and frequencies are determined. The effects of different methacrylate groups and salt content on the dielectric properties of copolymers are investigated. It is found that the dielectric constant increases systematically with increasing MMA and IBMA content in the copolymer. The samples with higher salt content show higher ac-conductivities

Preparation and characterization of acrylonitrile-ethyl methacrylate copolymers and the effect of LiClO4 salt on electrical properties of copolymer films

Copolymers of poly(acrylonitrile-co-ethyl methacrylate), P(AN-EMA), with three different EMA content and parent homopolymers were synthesized by emulsion polymerization. The chemical composition of copolymers were identified by FTIR, H-1-NMR and C-13-NMR spectroscopy. The thermal properties of copolymers were modified by changing the EMA content in copolymer compositions. Various amounts of LiClO4 salt loaded (PAN-co-PEMA) copolymer films were prepared by solution casting. The dielectric properties of these films at different temperatures and frequencies were investigated. It was found that the dielectric constant and ac-conductivity of copolymer films were strongly influenced by the salt amounts and EMA content in copolymers. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 201