Read by QxMD icon Read

chemical curing nanocomposites

Yi Yan, Vitor Sencadas, Tiantian Jin, Xufeng Huang, Wilford Lie, Dongbin Wei, Zhengyi Jiang
Processing conditions deeply affect the mechanical, chemical and biological properties of elastomeric based nanocomposites. In this work, multi-walled carbon nanotubes (MWCNTs) were dispersed in poly(glycerol sebacate) (PGS) prepolymer, followed by curing under vacuum at 120 °C. It was observed an increase of the water contact angle with the amount of MWCNTs added, as well as the tensile strength and Young modulus, without compromising the elastomeric behaviour of the pristine PGS matrix. The cross-linking degree was determined by the Flory-Rehner swelling method and through the mechanical rubber elasticity model, and an increase of more than six-fold was observed, which demonstrates the chemical conjugation between the MWCNTs and the PGS polymer chains, resulting in stiff and elastomeric nanocomposites...
July 1, 2018: Journal of Colloid and Interface Science
Youssef Snoussi, Stéphane Bastide, Manef Abderrabba, Mohamed M Chehimi
There is a growing interest in sonochemistry for either the controlled design of nanostructured materials or for the synthesis of polymers and polymer composites. It is fast and highly efficient method that provides materials with exceptional and enhanced structural and chemical properties. Herein, we take advantage of the versatile sonochemical process in order to design core/double layered shell nanocomposite denoted by Fe3 O4 @NH2 -mesoporous silica@ PPy/Pd. This magnetic, multicomponent material was designed in a three-step sono-process: (i) synthesis of magnetic core, (ii) cure of mesoporous silica, and (iii) sonochemical deposition of PPy/Pd...
March 2018: Ultrasonics Sonochemistry
Tinh Nguyen, Elijah J Petersen, Bastien Pellegrin, Justin M Gorham, Thomas Lam, Minhua Zhao, Lipiin Sung
Multiwall carbon nanotubes (MWCNTs) are nanofillers used in consumer and structural polymeric products to enhance a variety of properties. Under weathering, the polymer matrix will degrade and the nanofillers may be released from the products potentially impacting ecological or human health. In this study, we investigated the degradation of a 0.72 % (by mass) MWCNT/amine-cured epoxy nanocomposite irradiated with high intensity ultraviolet (UV) light at various doses, the effects of UV exposure on the surface accumulation and potential release of MWCNTs, and possible mechanisms for the release resistance of the MWCNT surface layer formed on nanocomposites by UV irradiation...
May 2017: Carbon
Ming Wang, Kai Zhang, Xin-Xin Dai, Yin Li, Jiang Guo, Hu Liu, Gen-Hui Li, Yan-Jun Tan, Jian-Bing Zeng, Zhanhu Guo
Formation of highly conductive networks is essential for achieving flexible conductive polymer composites (CPCs) with high force sensitivity and high electrical conductivity. In this study, self-segregated structures were constructed in polydimethylsiloxane/multi-wall carbon nanotube (PDMS/MWCNT) nanocomposites, which then exhibited high piezoresistive sensitivity and low percolation threshold without sacrificing their mechanical properties. First, PDMS was cured and pulverized into 40-60 mesh-sized particles (with the size range of 250-425 μm) as an optimum self-segregated phase to improve the subsequent electrical conductivity...
June 2, 2017: Nanoscale
Mehrez E El-Naggar, Ahmed G Hassabo, Amina L Mohamed, Tharwat I Shaheen
A simple chemical synthetic route was designed to prepare zinc oxide nanoparticles (ZnO-NPs) by using sodium alginate as anti-agglomeration agent in the presence of sodium hydroxide as alkali. Next, surface modification of ZnO-NPs with SiO2 nanoparticles was achieved as per to sol-gel process. Further enhancing of the multifunctional properties of SiO2@ZnO-NPs was conducted successfully thanks to (aminopropyl)triethoxysilan (APTES) and vinyltriethoxysilan (VTES) which, in turns, increase the affinity of the SiO2@ZnO-NPs nanocomposite towards glycosidic chains of cotton fabrics...
March 21, 2017: Journal of Colloid and Interface Science
Saeed Beigi Burujeny, Hamid Yeganeh, Mohammad Atai, Hoshyar Gholami, Marziyeh Sorayya
OBJECTIVE: Deterioration of mechanical strength for the dental composite containing ionic bactericidal compounds restricts the widespread utilization of this class of useful materials. This problem is originated from the reduction of the intermolecular interaction of polymeric network due to plasticization effect of absorbed water molecules penetrated between the chain segments. The main goal of this study is the synthesis of the highly efficient bactericidal additive with low hydrophilicity and consequently the least adverse effect on the final mechanical strength of the dental composite...
January 2017: Dental Materials: Official Publication of the Academy of Dental Materials
Farman Ali, Shaukat Saeed, Syed Sakhawat Shah, Fazal Rahim, Laurent Duclaux, Jean-Marc Levêque, Laurence Reinert
BACKGROUND: Sulfonated polyimides (SPIs) are considered as the promising alternatives to Nafion as membrane materials for the polymer electrolyte membrane (PEM). They generally exhibit high ionic conductivity, good mechanical properties, excellent thermal and chemical stabilities. The six-membered ring, naphthalenic anhydride-based SPIs, not only exhibit superior chemical and thermo-oxidative stabilities but are also more resistant to hydrolysis than their five-membered phthalic anhydride-based SPIs...
October 25, 2016: Recent Patents on Nanotechnology
Farman Ali, Shaukat Saeed, Syed Sakhawat Shah, Fazal Rahim, Laurent Duclaux, Jean-Marc Levêque, Laurence Reinert
BACKGROUND: Sulfonated polyimides (SPIs) are considered as the promising alternatives to Nafion as membrane materials for the polymer electrolyte membrane (PEM). They generally exhibit high ionic conductivity, good mechanical properties, excellent thermal and chemical stabilities. The six-membered ring, naphthalenic anhydride-based SPIs, not only exhibit superior chemical and thermo-oxidative stabilities but are also more resistant to hydrolysis than their five-membered phthalic anhydride-based SPIs...
2016: Recent Patents on Nanotechnology
Farid Khelifa, Youssef Habibi, Leila Bonnaud, Philippe Dubois
The present study focuses on the use of cellulose nanocrystals (CNC) as the main constituent of a nanocomposite material and takes advantage of hydroxyl groups, characteristic of the CNC chemical structure, to thermally cross-link an epoxy resin. An original and simple approach is proposed, based on the collective sticking of CNC building blocks with the help of a DGEBA/TGPAP-based epoxy resin. Scientific findings suggest that hydroxyl groups act as a toxic-free cross-linking agent of the resin. The enhanced protection against water degradation as compared to neat CNC film and the improvement of mechanical properties of the synthesized films are attributed to a good compatibility between the CNC and the resin...
April 27, 2016: ACS Applied Materials & Interfaces
Mai Xuan Dung, Jin-Kyu Choi, Hyun-Dam Jeong
Striving to replace the well known silicon nanocrystals embedded in oxides with solution-processable charge-trapping materials has been debated because of large scale and cost effective demands. Herein, a silicon quantum dot-polystyrene (SiQD-PS) nanocomposite (NC) was synthesized by post-functionalization of hydrogen-terminated silicon quantum dots (H-SiQDs) with styrene using a thermally induced surface-initiated polymerization approach. The NC contains two miscible components: PS and SiQD@PS which, respectively, are polystyrene and polystyrene chains-capped SiQDs...
April 10, 2013: ACS Applied Materials & Interfaces
Luís Eduardo Silva Soares, Sídnei Nahórny, Airton Abrahão Martin
This in vitro study evaluated the effect of light curing unit (LCU) type, mouthwashes, and soft drink on chemical degradation of a nanofilled resin composite. Samples (80) were divided into eight groups: halogen LCU, HS--saliva (control); HPT--Pepsi Twist®; HLC--Listerine®; HCP--Colgate Plax®; LED LCU, LS--saliva (control); LPT--Pepsi Twist®; LLC--Listerine®; LCP--Colgate Plax®. The degree of conversion analysis and the measure of the peak area at 2,930 cm-1 (organic matrix) of resin composite were done by Fourier-transform Raman spectroscopy (baseline, after 7 and 14 days)...
April 2013: Microscopy and Microanalysis
Sheng-Hao Hsu, Rung-Shu Chen, Yuan-Ling Chang, Min-Huey Chen, Kuo-Chung Cheng, Wei-Fang Su
Low-shrinkage resin-based photocurable liquid crystalline epoxy nanocomposite has been investigated with regard to its application as a dental restoration material. The nanocomposite consists of an organic matrix and an inorganic reinforcing filler. The organic matrix is made of liquid crystalline biphenyl epoxy resin (BP), an epoxy resin consisting of cyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (ECH), the photoinitiator 4-octylphenyl phenyliodonium hexafluoroantimonate and the photosensitizer champhorquinone...
November 2012: Acta Biomaterialia
Maria M Karabela, Irini D Sideridou
OBJECTIVE: The purpose of this work was the study of the effect of the amount of a urethane dimethacrylate silane (UDMS) coupling agent on physical properties of dental light-cured resin nanocomposites based on Bis-GMA/TEGDMA (50/50 wt/wt) matrix and Aerosil OX50 as filler. METHODS: Silica nanoparticles (Aerosil OX 50) used as filler were silanized with 5 different amounts of UDMS 1.0, 2.5, 5.0, 7.5 and 10 wt% relative to silica. The silanizated silica nanoparticles were identified by FT-IR spectroscopy and thermogravimetric analysis (TGA)...
November 2011: Dental Materials: Official Publication of the Academy of Dental Materials
R Sanctuary, J Baller, B Zielinski, N Becker, J K Krüger, M Philipp, U Müller, M Ziehmer
The influence of Al(2)O(3) nanoparticles on the curing of an epoxy thermoset based on diglycidyl ether of bisphenol A was investigated using temperature-modulated differential scanning calorimetry (TMDSC) and rheology. Diethylene triamine was used as a hardener. TMDSC not only allows for a systematic study of the kinetics of cure but simultaneously gives access to the evolution of the specific heat capacities of the thermosets. The technique thus provides insight into the glass transition behaviour of the nanocomposites and hence makes it possible to shed some light on the interaction between the nanoparticles and the polymer matrix...
January 21, 2009: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Prashanth Badrinarayanan, Josh Leonard, Michael R Kessler
In this work, the effect of multiwalled carbon nanotubes on the properties of a unique, low viscosity bisphenol E cyanate ester (BECy) resin is characterized during various stages of nanocomposite preparation. The effect of surface functionalization, with nanotubes containing hydroxyl groups (OH CNTs) and carboxylic acid groups (COOH CNTs), on the rheological, cure, thermal, and impact properties of the nanocomposite properties are also examined. Based on rheology measurements prior to cure, the unfunctionalized nanotube suspensions are found to exhibit the highest viscosity and the most dramatic shear thinning behavior...
May 2011: Journal of Nanoscience and Nanotechnology
Esra Uzer Çelık, Akin Aladağ, L Şebnem Türkün, Gökhan Yilmaz
UNLABELLED: The aims of this study were to: (1) evaluate the A2 shades of various types and brands of resin composites to determine if any color differences occurred before and after polymerization and after 1 month of storage in water and (2) examine the correlation among the color changes and changes in Commission internationale de l'éclairage L*, a*, and b* values after polymerization and after 1 month of storage in water. One submicron-hybrid (Spectrum TPH3, DENTSPLY DeTrey, Milford, DE, USA), one nano-filled (Filtek Supreme XT, 3 M ESPE, St...
June 2011: Journal of Esthetic and Restorative Dentistry
C-D Tran, S Lucas, D G Phillips, L K Randeniya, R H Baughman, T Tran-Cong
A direct process for manufacturing polymer carbon nanotube (CNT)-based composite yarns is reported. The new approach is based on a modified dry spinning method of CNT yarn and gives a high alignment of the CNT bundle structure in yarns. The aligned CNT structure was combined with a polymer resin and, after being stressed through the spinning process, the resin was cured and polymerized, with the CNT structure acting as reinforcement in the composite. Thus the present method obviates the need for special and complex treatments to align and disperse CNTs in a polymer matrix...
April 8, 2011: Nanotechnology
Mary Laura Lind, Daniel Eumine Suk, The-Vinh Nguyen, Eric M V Hoek
Herein we report on the formation and characterization of pure polyamide thin film composite (TFC) and zeolite-polyamide thin film nanocomposite (TFN) reverse osmosis (RO) membranes. Four different physical-chemical post-treatment combinations were applied after the interfacial polymerization reaction to change the molecular structure of polyamide and zeolite-polyamide thin films. Both TFC and TFN hand-cast membranes were more permeable, hydrophilic, and rough than a commercial seawater RO membrane. Salt rejection by TFN membranes was consistently below that of hand-cast TFC membranes; however, two TFN membranes exhibited 32 g/L NaCl rejections above 99...
November 1, 2010: Environmental Science & Technology
S G Prolongo, M R Gude, A Ureña
Epoxy nanocomposites were fabricated using two kinds of nanofiller, amino-functionalized multi-walled carbon nanotubes (CNTs) and non-treated long carbon nanofibers (CNFs). The non-cured mixtures were analysed through viscosity measurements. The effect of the nanoreinforcement on the curing process was determined by differential scanning calorimetry. Finally, the characterisation of cured nanocomposites was carried out studying their thermo-mechanical and electrical behaviour. At room temperature, the addition of CNTs causes a viscosity increase of epoxy monomer much more marked than the introduction of CNFs due to their higher specific area...
October 2009: Journal of Nanoscience and Nanotechnology
Z Spitalsky, G Tsoukleri, D Tasis, C Krontiras, S N Georga, C Galiotis
A versatile processing technique for fabricating epoxy nanocomposites with a high weight fraction of oxidized multi-walled carbon nanotubes is presented. Thin carbon nanotube based preforms were prepared through an oxidation-filtration protocol and then immersed in a pre-polymerized epoxy/curing agent solution in acetone. By adjusting the conditions for the oxidation of carbon nanotubes and the epoxy concentration in the as-prepared solution, high loading of graphitic nanostructures was obtained. Tensile tests indicated that the elastic modulus and strength of certain composites prepared by in situ polymerization as above were improved by 100% and 60%, respectively, compared to neat epoxy...
October 7, 2009: Nanotechnology
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"