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Thermal Stability and Rheological Behaviors of High-Density Polyethylene/Fullerene Nanocomposites
Liping Zhao,Ping'an Song,Zhenhu Cao,Zhengping Fang,Zhenghong Guo
Journal of Nanomaterials , 2012, DOI: 10.1155/2012/340962
Abstract: High-density polyethylene/fullerene (HDPE/C60) nanocomposites with the C60 loading that varied from 0.5 to 5.0% by weight were prepared via melt compounding. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) results showed that the presence of C60 could remarkably enhance the thermal properties of HDPE. A very low C60 loading (0.5 wt%) increased the onset degradation temperature from 389°C to 459°C and decreased the heat release from 3176 J/g to 1490 J/g. The larger the loading level of C60, the better the thermal stability of HDPE/C60 nanocomposites. Rheological investigation results showed that the free radical trapping effect of C60 was responsible for the improved thermal stability of HDPE.
Linear low-density polyethylene/silica micro- and nanocomposites: dynamic rheological measurements and modelling
eXPRESS Polymer Letters , 2010, DOI: 10.3144/expresspolymlett.2010.16
Abstract: Linear low-density polyethylene (LLDPE) based composites were prepared by melt compounding with 1, 2, 3 and 4 vol% of various kinds of amorphous silicon dioxide (SiO2) micro- and nanoparticles. Dynamic rheological tests in parallel plate configuration were conducted in order to detect the role of the filler morphology on the rheological behaviour of the resulting micro- and nanocomposites. A strong dependence of the rheological parameters from the filler surface area was highlighted, with a remarkable enhancement of the storage shear modulus (G′) and of the viscosity (η) in fumed silica nanocomposites and in precipitated silica microcomposites, while glass microbeads only marginally affected the rheological properties of the LLDPE matrix. This result was explained considering the formation of a network structure arising from particle-particle interactions due to hydrogen bonding between silanol groups. A detailed analysis of the solid like behaviour for the filled samples at low frequencies was conducted by fitting viscosity data with a new model, based on a modification of the original De Kee-Turcotte expression performed in order to reach a better modelling of the high-frequency region.
Solvothermal Synthesis of Boehmite and γ-Alumina Nanorods
Mingguo MA,Yingjie ZHU,Guofeng CHENG,Yuehong HUANG,

材料科学技术学报 , 2008,
Abstract: Boehmite nanorods were synthesized by a solvothermal method using AlCl3-6H2O in mixed solvents of water and aniline. The solvothermal time, heating temperature and the concentration of aniline have effects on the morphology of boehmite. γ-alumina nanorods were prepared by a simple thermal transformation of boehmite nanorods. A rational mechanism based on the oriented attachment is proposed for the formation of boehmite nanorods. The products were characterized by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). Photoluminescence (PL) spectrum of the boehmite nanorods was also investigated.
Rheological properties of alumina injection feedstocks
Krauss, Vivian Alexandra;Pires, Eduardo Nunes;Klein, Aloísio Nelmo;Fredel, Márcio Celso;
Materials Research , 2005, DOI: 10.1590/S1516-14392005000200018
Abstract: the rheological behavior of alumina molding feedstocks containing polyethylene glycol (peg), polyvinylbutyral (pvb) and stearic acid (sa) and having different powder loads were analyzed using a capillary rheometer. some of the feedstocks showed a pseudoplastic behavior of n < 0, which can lead to the appearance of weld lines on molded parts. their viscosity also displayed a strong dependence on the shear rate. the slip phenomenon, which can cause an unsteady front flow, was also observed. the results indicate that the feedstock containing a lower powder load displayed the best rheological behavior. the 55 vol. % powder loaded feedstock presented the best rheological behavior, thus appearing to be more suitable than the formulation containing a vol. 59% powder load, which attained viscosities exceeding 103 pa.s at low shear rates, indicating its unsuitability for injection molding.
N.I.Kurbanova, Z.N.Huseynova, N.Y.Ishenko, A.T.Aliyev, T.M.Guliyeva, S.K.Ragimova, S.A.Rzaeva
Azerbaijan Cjemical Journal , 2019, DOI: 10.32737/0005-2531-2019-1-54-58
Abstract: The effect of additives of metal-containing nanofillers including nanoparticles of zinc oxide stabilized on a polymer matrix of maleinized polyethylene on the properties of nanocomposites based on isotactic polypropylene by methods X-ray phase and thermogravimetric analyses was studied. The improvement of the strength and rheological indexes, as well as the thermooxidative stability of the nanocomposites obtained was revealed
Tensile mechanical response of polyethylene – clay nanocomposites.
eXPRESS Polymer Letters , 2007, DOI: 10.3144/expresspolymlett.2007.21
Abstract: In this work we report on the microstructural and the mechanical characteristics of high density polyethylene (HDPE)-clay nanocomposites, with particular attention to the creep behaviour. The samples were prepared through melt compounding, using two high-density polyethylenes with different melt flow rate (MFR), two different organo-modified clays, and changing the relative amount of a polyethylene grafted with maleic anhydride (PEgMA) compatibilizer. The intercalation process is more effective as the matrix melt viscosity decreases (higher MFR), while the clay interlamellar spacing increases as the compatibilizer amount increases. The relative stiffness of the nanocomposites increases with the addition of clay, with a limited enhancement of the relative yield stress. The better intercalation obtained by the addition of the compatibilizer is not accompanied by a concurrent improvement of the tensile mechanical properties. The creep resistance is enhanced by the introduction of clay, with an appreciable dependence on both the polyethylene and the clay type.
Nanocomposites materials generated from a spray
Marques, R.F.C.;Caiut, J.M.A.;Paiva-Santos, C.O.;Ribeiro, S.J.L.;Messaddeq, Y.;Garcia, C.;Neumeyer, D.;Dexpert, H.;Verelst, M.;Dexpert-Ghys, J.;
Brazilian Journal of Physics , 2009, DOI: 10.1590/S0103-97332009000200009
Abstract: the spray pyrolysis (sp) process has been employed at moderate temperature (470-970 k) for the synthesis of micro- and nano-particles of hydrated metal oxides and of related nanocomposites. it has been applied to iron nitrate solutions, without or with the addition of sodium chloride as a flux. after removal of the flux, nanocomposites of ferrihydrite (5fe2o3,9h2o) / hematite (α- fe2o3) / and an amorphous fe2o3 are obtained, with surface area 140 m2/g. it has been applied also to a sol of aluminum-tri-sec-butoxide, without or with activation by europium or terbium ions. boehmite (γ-alooh) powders are synthesized at 470 k, with surface area equal to 180 m2/g. transition alumina (γ-al2o3) are synthesized at 970 k. nanocomposites made by reaction of the boehmite or γ-al2o3 particles with the amino acid asparagin (asn) have been prepared and characterized. the luminescence of the eu3+ or tb3+ doped nanocomposites has been investigated: they can be considered as bio-compatible luminescent nanoparticles.
Pore surface fractal analysis of PEG and La(III)-doped mesoporous alumina obtained by the sol–gel method  [PDF]
Journal of the Serbian Chemical Society , 2010,
Abstract: Active porous alumina was prepared via a sol–gel method and subjected to thermal treatment in the temperature range 500–1200 °C. The addition of lanthanum effectively inhibited the surface area loss of the aluminas. Fractal analysis from nitrogen adsorption isotherm was used to study the pore surface roughness of alumina samples with different chemical compositions (PEG, PEG and lanthanum) and calcinations conditions in terms of the surface fractal dimension, d. The Mahnke and M gel (MM) model was used to determine the value of d of La(III)-doped alumina. Following the MM model, the d value of the activated aluminas increased as the calcination temperature increased from 500 to 700 °C but decreased after calcination at 1000, 1100 and 1200 °C. The addition of polyethylene glycol (PEG 5600) to the boehmite sol reduced the surface fractal of the activated alumina due to the heterogeneous distribution of the pores. With increasing La(III) concentration from 0.015 to 0.045 mol La(III)/ /mol Al(III), the d value of La-modified alumina samples decreased, indicating a smoother surface. The obtained PEG+La-doped boehmite sol can be used as a precursor dispersion for the deposition of mesoporous alumina coatings on stainless steel foil, by the spray pyrolysis method.
Mechanical, morphological and rheological properties of polyamide 6/organo-montmorillonite nanocomposites
eXPRESS Polymer Letters , 2007, DOI: 10.3144/expresspolymlett.2007.14
Abstract: Polyamide (PA6) nanocomposites containing 4wt% organo-montmorillonite (OMMT) were melt-compounded followed by injection molding. The mechanical properties of the PA6/OMMT nanocomposites were studied through tensile and flexural tests. The rheological behaviour of the nanocomposites was determined by plate/plate rheological measurements. Attempts were made to trace the rheological parameters that reliably reflect the observed changes in the clay dispersion. X-ray diffraction (XRD) and atomic force microscopy (AFM) were used to characterize the exfoliation and dispersion of the OMMT in the PA6 matrix. The thermal properties of PA6/OMMT nanocomposite were characterized by Dynamic Mechanical Thermal Analysis (DMTA). The tensile modulus and strength of the PA6 was increased in the presence of OMMT. The flexural strength of PA6/OMMT was approximately doubled compared to the tensile strength value. The significant enhancement of both tensile and flexural strength was attributed to the delaminated clay formation. XRD and AFM results revealed the formation of PA6 nanocomposites as the OMMT was successfully exfoliated.
Rheology and Gelling Behavior of Boehmite Sols  [PDF]
M.A. Islam,Chu Chi Ming,Pogaku Ravindra,Eng-Seng Chan
Journal of Applied Sciences , 2011,
Abstract: Rheological studies of boehmite sols based on pH was (1) to study the nature of flow properties of the boehmite sols and (2) to identify the sol-gel transition of boehmite sols with the change of pH of the liquid. It is evident that the shear rate and viscosity of the liquid exhibit a pseudoplastic (shear thinning) flow behavior for all pH level. The transformation of sol-gel at low pH probably due to the hydrogen bond between the layers of the boehmite structure. The temperature has an appreciable effect on the activation energy during the sol-gel transition. The flow activation energies ?E? are in the range of 1.75 to 6.25 J mol-1 at temperature 298-384 K. Based on these results, the flow activation energy of boehmite sols sharply decreases with decreasing the pH. The flocculation of the suspension at pH 4 to 1 showed to be favourable in term of enhanced density of boehmite.
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