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Polymer nanocomposite

Kuruma Malkappa, Jayita Bandyopadhyay, Suprakas Sinha Ray
Polylactide (PLA) is one of the most widely used organic bio-degradable polymers. However, it has poor flame retardancy characteristics. To address this disadvantage, we performed melt-blending of PLA with intumescent flame retardants (IFRs; melamine phosphate and pentaerythritol) in the presence of organically modified montmorillonite (OMMT), which resulted in nanobiocomposites with excellent intumescent char formation and improved flame retardant characteristics. Triphenyl benzyl phosphonium (OMMT-1)- and tributyl hexadecyl phosphonium (OMMT-2)-modified MMTs were used in this study...
October 16, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Athanasia A Septevani, David A C Evans, Alireza Hosseinmardi, Darren J Martin, John Simonsen, John F Conley, Pratheep K Annamalai
Analysis of cellulose nanocrystals (CNCs) at low volume fractions in polymer nanocomposites through conventional electron microscopy still remains a challenge due to insufficient contrast between CNCs and organic polymer matrices. Herein, a methodology for enhancing the contrast of CNC, through atomic layer deposition (ALD) of alumina (Al2 O3 ) on CNCs is demonstrated. The metal oxide coated CNC allows clear visualization by transmission electron microscopy, when they are dispersed in water and polyol. A coating of about 6 ± 1 nm thick alumina layer on the CNC is achieved after 50 ALD cycles...
October 16, 2018: Small
Quan Zhou, Yue Wang, Jiajia Xiang, Ying Piao, Zhuxian Zhou, Jianbin Tang, Xiangrui Liu, Youqing Shen
Calcium phosphate (CaP) nanoparticles present a class of promising nonviral gene delivery carriers due to their easy-preparation procedure, low toxicity and high transfection efficiency. PEGylated polyanion block copolymer was widely used to control the CaP crystal growth during CaP co-precipitation with therapeutic genes. However, there also exists a competition between the entrapped gene and polyanion in the system, which results in reduced stability and low gene entrapment efficiency. To solve this problem, herein, we demonstrate a non-anion stabilization strategy using a boroxole-containing block polymer, PEG-b-poly(benzoxaborole) (PEG-PBO), which forms pH-responsive boronic ester bonds with ribose rings of siRNA and also excellently adhers to the hydroxyapatite surface of CaP...
October 17, 2018: Biomaterials Science
Megha A Deshmukh, Gajanan A Bodkhe, Sumedh Shirsat, Arunas Ramanavicius, Mahendra D Shirsat
Heavy metal ions are considered as one of the major water pollutants, revealing health hazards as well as threat to the ecosystem. Therefore, investigation of most versatile materials for the sensitive and selective detection of heavy metal ions is need of the hour. Proposed work emphasizes the synthesis of conducting polymer and carbon nanotube nanocomposite modified with chelating ligand for the detection of heavy metal ions. Carbon nanotubes are having well known features such as tuneable conductivity, low density, good charge transport ability, and current carrying capacity...
2018: Frontiers in Chemistry
Xin-Lu Liu, Hong-Fei Yao, Mei-Hong Chai, Wei He, Yan-Ping Huang, Zhao-Sheng Liu
The facile fabrication of single-walled carbon nanotubes (SWCNTs)-doping molecularly imprinted polymer (MIP) nanocomposite-based binary green porogen system, room-temperature ionic liquids (RTILs), and deep eutectic solvents (DESs) was developed for drug delivery system. With fenbufen (FB) as template molecule, 4-vinylpyridine (4-VP) was used as functional monomer, ethylene glycol dimethacrylate as cross-linking monomer, and 1-butyl-3-methylimidazoliumtetrafluoroborate and choline chloride/ethylene glycol as binary green solvent, in the presence of SWCNTs...
October 15, 2018: AAPS PharmSciTech
Joshua Avossa, Emiliano Zampetti, Fabrizio De Cesare, Andrea Bearzotti, Giuseppe Scarascia-Mugnozza, Giuseppe Vitiello, Eyal Zussman, Antonella Macagnano
The potentials to use the working temperature to tune both the sensitivity and the selectivity of a chemical sensor based on a nanostructured and nanocomposite polymer layer have been investigated and described. Thus, in a single step, a peculiar chemical layer was grown up onto IDE (Interdigitated Electrode) microtransducers by electrospinning deposition and using a single-needle strategy. The 3-component nanofibers, obtained from a mixture of polystyrene and polyhydroxibutyrate (insulating thermoplastics) and a known concentration of mesoporous graphitized carbon nanopowder, appeared highly rough on the surface and decorated with jagged islands but homogeneous in shape and diameter, with the nanofillers aggregated into clusters more or less densely packed through the fibers...
2018: Frontiers in Chemistry
Safiya Allie, Ignacio Hegoburu, Min Jeong Shin, Jung Young Jung, Violeta Toader, Alejandro Rey, Ezequiel R Soule, Linda Reven
Liquid crystal (LC)-polymer blends are important stimuli responsive materials already employed in a wide range of applications whereas nanoparticle (NP)-LC blends are an emerging class of nanocomposites. Polymer ligands offer the advantages of synthetic simplicity along with chemical and molecular weight tunability. Here we compare the phase behavior of 5CB blended with poly(ethylene oxide) (PEO) and with gold NPs functionalized with thiolated PEO (AuNP-PEO) as a function of PEO concentration by DSC, POM and 13C NMR spectroscopy...
October 15, 2018: Soft Matter
Le Li, Rui-Ying Bao, Tao Gao, Zheng-Ying Liu, Bang-Hu Xie, Ming-Bo Yang, Wei Yang
Improving the physical properties of biobased polymers using bionanofillers is essential to preserve its biodegradability. This work presents a dopamine-induced functionalization of cellulose nanocrystals (CNCs) with polyethylene glycol (PEG), to enhance the crystallization, mechanical and barrier properties of poly(L -lactic acid) (PLLA) bionanocomposites. The effect of molecular weight of grafted PEG on the properties of PLLA is also studied. PEGylation of CNCs significantly enhance the crystallization of PLLA, especially for CNCs functionalized with PEG of lower molecular weight, which lead to balanced strength and ductility, and 66...
January 1, 2019: Carbohydrate Polymers
Bartolomeo Coppola, Nicola Cappetti, Luciano Di Maio, Paola Scarfato, Loredana Incarnato
In this study, the possibility of using a layered silicate-reinforced polylactic acid (PLA) in additive manufacturing applications was investigated. In particular, the aim of this work was to study the influence of printing temperature in the 3D printing process of PLA/clay nanocomposites. For this reason, two PLA grades (4032D and 2003D, D-isomer content 1.5 and 4, respectively) were melt-compounded by a twin screw extruder with a layered silicate (Cloisite 30B) at 4 wt %. Then, PLA and PLA/clay feedstock filaments (diameter 1...
October 11, 2018: Materials
Taoran Wang, Yangchao Luo
In this study, the innovative and multifunctional nanoparticles⁻hydrogel nanocomposites made with chitosan hydrogel beads and solid lipid⁻polymer hybrid nanoparticles (SLPN) were prepared through conjugation between SLPN and chitosan beads. The SLPNs were first fabricated via coating the bovine serum albumin (BSA)-emulsified solid lipid nanoparticles with oxidized dextran. The aldehyde groups of the oxidized dextran on the surface of the SLPN enabled an in situ conjugation with the chitosan beads through the Schiff base linkage...
October 11, 2018: International Journal of Molecular Sciences
Xinping Zhang, Huicheng Ren, Aihua He
Two-dimensional (2D) nanomaterials with unique features like a large surface-to-volume ratio and the quantum confinement effect have attracted great attention for applications in energy storage, catalysis, sensing, membranes, etc. Silica (SiO2)-based nanosheets, as members of the 2D material family, are extremely intriguing because of their unique electronic insulation, bio-compatibility and profound chemical and thermal stability. However, there is still a lack of available approaches for fabricating SiO2 nanosheets in a simple, large-scale and cost-effective fashion...
October 11, 2018: Nanoscale
Ulrica M Edlund, Tove Lagerberg, Eva Ålander
A water-based one-pot synthesis strategy for converting cellulose nanofibrils (CNF) into a hydrophobic and processable biopolymer grade is devised. CNF was chemically modified through admicellar polymerization, producing fibrils coated with fatty acrylate polymers. The proposed modification targets a change in the inter-fibrillar interactions and improved CNF compatibility with a degradable plastic composite matrix, poly(butylene adipate-co-terephthalate), PBAT, in composites prepared by melt extrusion. CNF had a clear reinforcing effect on PBAT, increasing Young's modulus by at least 35% and 169% at 5 and 20% (w/w) CNF content, respectively...
October 9, 2018: Biomacromolecules
Erkan Senses, Madhusudan Tyagi, Madeleine Pasco, Antonio Faraone
We present nanocomposite materials formed by using glassy star-shaped polymers as nanofillers and dispersing them in soft matrices. The resulting 'architecturally engineered' polymer nanocomposites structurally reside between the linear homopolymer blends and the conventional polymer nanocomposites with inorganic fillers, inducing reinforcement, which can be as strong as that of solid nanoparticles, or softening depending on the compactness and concentration of the nanoparticles. Such behavior can be traced back to the dynamical features at the local segmental and the chain level, which we investigated using neutron scattering over a wide range of time and length-scales in the glassy and melt states of the nanocomposites...
October 9, 2018: ACS Nano
Sandra S Gkermpoura, Konstantinia D Papadimitriou, Emmanuel N Skountzos, Ioannis Polyzos, Maria Giovanna Pastore Carbone, Athanasios Kotrotsos, Vlasis G Mavrantzas, Costas Galiotis, Constantinos Tsitsilianis
3-Arm PMMAs end-functionalized by pyrene were designed as dispersing/stabilizing agents for the liquid-phase exfoliation of graphite in low-boiling point solvents like chloroform. The synthetic procedure comprised ARGET ATRP controlled polymerization, click chemistry and the quaternization reaction of triazole, ensuring tailor-made, well-defined pyrene-functional star PMMAs. Among a series of different pyrene-functional macromolecular topologies, the (PMMA-py2)3 proved the most efficient exfoliation agent giving relatively high graphene concentration (0...
October 9, 2018: Nanoscale
Mete Bakir, Jacob L Meyer, Andre Sutrisno, James Economy, Iwona Jasiuk
Development of porous materials consisting of polymer host matrix enriched with bioactive ceramic particles that can initiate the reproduction of cellular organisms while maintaining in vivo mechanical reliability is a long-standing challenge for synthetic bone substitutes. We present hydroxyapatite (HA) reinforced aromatic thermosetting copolyester (ATSP) matrix bionanocomposite as a potential reconfigurable bone replacement material. The nanocomposite is fabricated by solid-state mixing a matching set of precursor oligomers with biocompatible pristine HA particles...
October 5, 2018: Scientific Reports
Huimin Zhou, Xin Xia, Pengfei Lv, Jin Zhang, Xuebin Hou, Min Zhao, Kelong Ao, Di Wang, Muhammad Naeem, Keyu Lu, Hui Qiao, Malgorzata Zimniewska, Qufu Wei
Integrating layered nanostructured MoS2 with superior structural stable TiO2 backbone to construct reciprocal MoS2-TiO2 based nanocomposites has been proved to be an effective strategy. Herein, 1T phase MoS2 nanograins doped C@TiO2/MoO3 composite nanofibers were achieved by partially sulfurizing MoOx/TiO2 precursors. Controlling the suitable preoxidation temperature before severe thermolysis of PVP, the TiO2/MoOx precursors appeared as array embedded into polymer induced by chemical coordination of Mo source and pyrrolidyl group of PVP...
October 4, 2018: ChemSusChem
Xi Zhang, Mike A Geven, Xinluan Wang, Ling Qin, Dirk W Grijpma, Ton Peijs, David Eglin, Olivier Guillaume, Julien E Gautrot
Background: Poly(trimethylene carbonate) (PTMC) has wide biomedical applications in the field of tissue engineering, due to its biocompatibility and biodegradability features. Its common manufacturing involves photofabrication, such as stereolithography (SLA), which allows the fabrication of complex and controlled structures. Despite the great potential of SLA-fabricated scaffolds, very few examples of PTMC-based drug delivery systems fabricated using photo-fabrication can be found ascribed to light-triggered therapeutics instability, degradation, side reaction, binding to the macromers, etc...
2018: International Journal of Nanomedicine
Mariem Errezma, Ayman Ben Mabrouk, Albert Magnin, Alain Dufresne, Sami Boufi
Aldehyde-functionalized cellulose nanocrystals (CN) with two aldehyde contents were produced by periodate oxidation and gentle sonication. The aldehyde-functionalized CNCs were shown to be an effective stabilizer in the Pickering emulsion polymerization of acrylate monomers using potassium persulfate (KPS)/metabisulfite redox initiation system at 50 °C without any added surfactant. The effect of CNC content on the particle size, zeta-potential, colloidal stability and film properties were discussed. CNCs with the highest aldehyde content impart better colloidal stability to the polymer dispersion and lower particle size...
December 15, 2018: Carbohydrate Polymers
Yao Zhou, Qi Li, Bin Dang, Yang Yang, Tao Shao, He Li, Jun Hu, Rong Zeng, Jinliang He, Qing Wang
High-temperature capability is critical for polymer dielectrics in the next-generation capacitors demanded in harsh-environment electronics and electrical-power applications. It is well recognized that the energy-storage capabilities of dielectrics are degraded drastically with increasing temperature due to the exponential increase of conduction loss. Here, a general and scalable method to enable significant improvement of the high-temperature capacitive performance of the current polymer dielectrics is reported...
October 3, 2018: Advanced Materials
Shengnan Xu, Ligang Chen, Ling Ma
The authors describe a fluorescent probe for sensitive and selective determination of quercetin, an indicator for the freshness of drinks. The probe consists of silica ball encapsulated graphitic carbon nitride (g-C3 N4 ) modified with a molecularly imprinted polymer (MIP). It was synthesized via reverse microemulsion. The resulting MIP@g-C3 N4 nanocomposite was characterized by fluorescence spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray powder diffraction...
October 3, 2018: Mikrochimica Acta
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