Investigation of thermal and dielectric properties of Fe3O4/high-density polyethylene nanocomposites

2017 ◽  
Vol 51 (28) ◽  
pp. 3923-3929 ◽  
Author(s):  
Fatemeh Ahangaran ◽  
Ali Hassanzadeh ◽  
Sirous Nouri ◽  
Rasoul Esmaeely Neisiany

High-density polyethylene nanocomposites containing Fe3O4 nanoparticles were prepared by employing melt mixing process. The amorphous Fe3O4 nanoparticles with average size about 50 nm were prepared by the conventional coprecipitation method from iron (ΙΙ and ΙΙΙ). Thermal and dielectric properties of high-density polyethylene and its nanocomposites were investigated via differential scanning calorimetry and electrochemical impedance spectroscopy. The crystalline structure of high-density polyethylene and Fe3O4/high-density polyethylene nanocomposite were studied by wide-angle X-ray diffraction, which confirmed orthorhombic crystalline structure. The results of thermal and dielectric analysis indicated that the addition of Fe3O4 nanoparticles to high-density polyethylene matrix leads to decreasing degree of crystallinity and improvement of dielectric constant.

2005 ◽  
Vol 59 (9) ◽  
pp. 1148-1154 ◽  
Author(s):  
Spiros Tzavalas ◽  
Vasilis G. Gregoriou

High-density polyethylene (HDPE)–clay nanocomposites have been prepared using the melt intercalation technique. Organically modified montmorillonite at various loadings (0.5–7%) was used as a nanoadditive. Fourier transform infrared spectroscopy (FT-IR) was utilized for the first time to monitor the stress-induced crystal-to-crystal transformations of the polyethylene matrix with respect to the clay loading as well as to the degree of mechanical strain. In addition, polarized infrared measurements revealed information on both the orientation and the stress-induced distortion of the crystals. It was concluded that the crystal-to-crystal transformations are hindered by the presence of the clay, which also prevented the crystals from orienting even at low clay loadings (1%). Finally, X-ray diffraction (XRD) and differential scanning calorimetry (DSC) measurements confirmed the presence of the stress-induced crystalline structures in agreement with the infrared measurements.


Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 361 ◽  
Author(s):  
Kartik Behera ◽  
Mithilesh Yadav ◽  
Fang-Chyou Chiu ◽  
Kyong Rhee

In this study, a graphene nanoplatelet (GNP) was used as a reinforcing filler to prepare poly(vinylidene fluoride) (PVDF)/high density polyethylene (HDPE) blend-based nanocomposites through a melt mixing method. Scanning electron microscopy confirmed that the GNP was mainly distributed within the PVDF matrix phase. X-ray diffraction analysis showed that PVDF and HDPE retained their crystal structure in the blend and composites. Thermogravimetric analysis showed that the addition of GNP enhanced the thermal stability of the blend, which was more evident in a nitrogen environment than in an air environment. Differential scanning calorimetry results showed that GNP facilitated the nucleation of PVDF and HDPE in the composites upon crystallization. The activation energy for non-isothermal crystallization of PVDF increased with increasing GNP loading in the composites. The Avrami n values ranged from 1.9–3.8 for isothermal crystallization of PVDF in different samples. The Young’s and flexural moduli of the blend improved by more than 20% at 2 phr GNP loading in the composites. The measured rheological properties confirmed the formation of a pseudo-network structure of GNP-PVDF in the composites. The electrical resistivity of the blend reduced by three orders at a 3-phr GNP loading. The PVDF/HDPE blend and composites showed interesting application prospects for electromechanical devices and capacitors.


2015 ◽  
Vol 30 (6) ◽  
pp. 855-884 ◽  
Author(s):  
AK Sudari ◽  
AA Shamsuri ◽  
ES Zainudin ◽  
PM Tahir

Three types of surfactants, specifically cationic, anionic, and nonionic, at different weight percentages were added into high-density polyethylene/low-density polyethylene/cellulose (HDPE/LDPE/cellulose) biocomposites via melt mixing. The cationic and anionic surfactants which are hexadecyltrimethylammonium bromide (HTAB) and sodium stearate (SS), respectively, were added from 4 to 20 wt%, whereas the nonionic surfactant which is sorbitan monostearate (SM) was added from 1 to 5 wt%. The mechanical testing results exhibited that the addition of HTAB increased tensile strength and tensile modulus, while SS deteriorated mechanical properties, while SM increased impact strength and tensile extension of the biocomposites. Based on the mechanical properties results, optimum weight percentages of HTAB and SM were 12 wt% and 4 wt%, respectively. The scanning electron microscopic micrographs displayed that the amount of cellulose fillers pullout decreased with the addition of HTAB, followed by SM, but it increased with SS. Fourier transform infrared spectra, X-ray diffractometer patterns, thermogravimetric analysis results, and differential scanning calorimetry thermograms have confirmed the presence of physical interactions only with the addition of HTAB and SM. Based on the results, compatibilizing effect was found in HTAB, whereas SM has not showed compatibilizing effect but instead plasticizing effect. However, neither compatibilizing nor plasticizing effect was exhibited by SS.


2016 ◽  
Vol 51 (18) ◽  
pp. 2665-2673 ◽  
Author(s):  
Behzad Kord ◽  
Mehdi Roohani

The physical, mechanical, thermal, and flammability properties of high-density polyethylene/old corrugated container composites reinforced with carbon nanotubes are presented in this study. High-density polyethylene/old corrugated container composites with different loadings of carbon nanotube (0, 1, 3, and 5 phc) were prepared by melt compounding followed by injection molding. Results indicated that the incorporation of carbon nanotube into high-density polyethylene, significantly improved the mechanical properties of the composites. The tensile and flexural properties achieved the maximum values when 3 phc carbon nanotube was added. Meanwhile, the impact strength of the composites progressively decreased with increasing carbon nanotube content. Furthermore, the water absorption and thickness swelling of the samples remarkably reduced with the addition of carbon nanotube. From thermogravimetric analysis data, the presence of carbon nanotube could enhance the thermal stability of the composites, especially the maximum weight loss rate temperature and also the better char residual was obtained at high loading level of carbon nanotube. Simultaneous differential scanning calorimetry thermograms revealed that the thermal degradation temperatures for the samples with carbon nanotube were much higher than those made without carbon nanotube. Moreover, it was found that the addition of carbon nanotube results in a significant enhancement in flame retardancy of the composites. Morphological observations showed that the nanoparticles were predominantly dispersed uniformly within the high-density polyethylene matrix.


2013 ◽  
Vol 652-654 ◽  
pp. 15-24 ◽  
Author(s):  
Xia Ran Miao ◽  
Yuan Jiang Qi ◽  
Xiao Yun Li ◽  
Yu Zhu Wang ◽  
Xiao Long Li ◽  
...  

The high density polyethylene (HDPE) nanocomposites were prepared by melt mixing HDPE with multi-wall carbon nanotubes (MWCNTs). In this work, the morphological, nucleation, crystallization and mechanical properties of the HDPE nanocomposites were studied by scanning electron microscopy, different scanning calorimetry, small-angle X-ray scattering and tensile testing. It was found that the tensile strength and Young’s modulus is increased by 42.4% and 116.5% at 3.wt% MWCNT loading compared to the pure HDPE. According to SEM results combined with SAXS, well-defined nanohybird shish-kebab (NHSK) entities exist in the composites, and in the shish-kebab structures fibrillous carbon nanotubes (MWCNTs) act as shish while HDPE lamellae act as kebab. The crystallization behavior, probed by DSC, suggests that MWCNTs have strong nucleation ability and shear stress plays an important role in polymer crystallization process. The mechanical properties demonstrated that the formation of the Shish-kebab structures improved the interfacial adhesion and brought obvious mechanical enhancement for the HDPE/MWCNTs nanocomposites.


2011 ◽  
Vol 103 ◽  
pp. 447-451
Author(s):  
Bing Li ◽  
Xue Mei Qin ◽  
Bao Shan Shi

Physics mechanics properties of polymer materials don’t only depend on their chemical constitution, molecular weight and distribution of molecular weight, but also depend on their agglomerate configuration. The effect of vibration on the microstructure and mechanical properties of high-density polyethylene (HDPE) sheets, obtained through vibration plasticating extruder in low temperature, were studied systematically. Crystalline polymer is analyzed by differential scanning calorimetry(DSC), wide angle X ray diffraction(WAXD). The test result which represents parameters of crystalline structure is helped to judge the outside factors for crystalline structure, such as melting point, crystallinity and heat of fusion by DSC and crystallinity, crystal plane distance and grain size by WAXD, and canning electron microcopy (SEM). The results indicate that the vibration extrudate in low temperature has higher crystallinity, perfect crystallite, and strong inter-spherulite ties.


2020 ◽  
Vol 32 (9) ◽  
pp. 2293-2297
Author(s):  
V.S. KUMAWAT ◽  
J.P. BHATT ◽  
D. SHARMA ◽  
S.C. AMETA ◽  
R. AMETA

The photodegradation of high density polyethylene (HDPE) using CaO nanoparticles as a catalyst was carried out using 500 W lamp. After exposure, morphology as well as thermal properties of the HDPE was investigated by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). SEM results showed that the HDPE is more prone to crack into small fragments, which indicated a rise in crystallinity with different amounts of catalyst i.e. CaO nanoparticles. The DSC results confirmed the remarkable influence of photodegradation on degree of crystallinity (XC%), fusion enthalpy (ΔH J g-1) and melting temperature (Tm) of HDPE. Infrared spectrometry (FTIR) demonstrated all functional groups of HDPE, present before and after photodegradation. Overall results showed that HDPE was photodegraded into small fragments successfully by using CaO nanopartilces, where different functional groups such as carbonyl, esters and vinyl were obtained during chain scission.


1994 ◽  
Vol 38 ◽  
pp. 495-502
Author(s):  
Kenneth B. Schwartz ◽  
Jinlong Cheng ◽  
Vijay N. Reddy ◽  
Matilda Fone ◽  
Howard P. Fisher

Abstract The degree of crystallinity and unit cell parameters have been determined using WAXS on a number of compression molded high-density polyethylene (HDPE) plaques processed at widely varying conditions of crystallization and annealing times and temperatures. Changes in unit cell parameters with variations in processing conditions can be explained in terms of increases in lamellar thickness of polyethylene crystals with increasing thermal treatments. Concomitant increases in the degree of crystallinity of these samples can also be explained in terms of lamellar thickening and other changes in polyethylene morphology. Crystallinity determinations using XRD data are also compared with values determined by differential scanning calorimetry (DSC) and solid-state 13C nuclear magnetic resonance (NMR). Comparisons of crystallinity values obtained by these three different techniques can reveal details of the morphology of HDPE including the presence of an interfacial zone in addition to the crystalline and amorphous components of the system.


2018 ◽  
Vol 38 (9) ◽  
pp. 827-837 ◽  
Author(s):  
Farida Yahiaoui ◽  
Ouahida Bensebia ◽  
Assia Siham Hadj-Hamou

Abstract Composite materials made from high density polyethylene (HDPE) and polystyrene (PS) were successfully prepared in different HDPE/PS weight ratios, by melt mixing 3 wt% of bentonite clay organically modified with hexadecyl ammonium chloride (organo-modified bentonite, OBT). The structure and morphology of these composites were examined by X-ray diffraction and scanning electron microscopy. Morphological changes between the composite and the constituent materials were observed. The decrease in PS (or HDPE) particle size in HDPE/PS 70/30 (or 30/70) that blend after the OBT addition reflects a clear improvement in the HDPE/PS blend compatibility. The effect of OBT on the thermal and mechanical properties was investigated by differential scanning calorimetry, thermogravimetric analysis, and tensile measurements. The main results show a decrease in the HDPE crystallinity in the composite matrices, which reaches 25% for HDPE/PS/OBT 29/68/3 composite, also an improvement of the thermal stability, as evidenced by the higher Tonset values, and finally a reinforcement of the tensile properties as compared to the unfilled blends. Indeed, a significant enhancement of the tensile modulus (~130%) is observed for the 68/29/3 composite matrix as compared to the 70/30 unfilled blend.


2003 ◽  
Vol 774 ◽  
Author(s):  
Susan M. Rea ◽  
Serena M. Best ◽  
William Bonfield

AbstractHAPEXTM (40 vol% hydroxyapatite in a high-density polyethylene matrix) and AWPEX (40 vol% apatite-wollastonite glass ceramic in a high density polyethylene matrix) are composites designed to provide bioactivity and to match the mechanical properties of human cortical bone. HAPEXTM has had clinical success in middle ear and orbital implants, and there is great potential for further orthopaedic applications of these materials. However, more detailed in vitro investigations must be performed to better understand the biological interactions of the composites and so the bioactivity of each material was assessed in this study. Specifically, the effects of controlled surface topography and ceramic filler composition on apatite layer formation in acellular simulated body fluid (SBF) with ion concentration similar to those of human blood plasma were examined. Samples were prepared as 1 cm × 1 cm × 1 mm tiles with polished, roughened, or parallel-grooved surface finishes, and were incubated in 20 ml of SBF at 36.5 °C for 1, 3, 7, or 14 days. The formation of a biologically active apatite layer on the composite surface after immersion was demonstrated by thin-film x-ray diffraction (TF-XRD), environmental scanning electron microscopy (ESEM) imaging and energy dispersive x-ray (EDX) analysis. Variations in sample weight and solution pH over the period of incubation were also recorded. Significant differences were found between the two materials tested, with greater bioactivity in AWPEX than HAPEXTM overall. Results also indicate that within each material the surface topography is highly important, with rougher samples correlated to earlier apatite formation.


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