Glass transition activation energy of CdS/PMMA nano-composite and its dependence on composition of CdS nano-particles

2010 ◽  
Vol 106 (3) ◽  
pp. 921-925 ◽  
Author(s):  
D. Patidar ◽  
Sonalika Agrawal ◽  
N. S. Saxena
Keyword(s):  
Activation Energy ◽  
Glass Transition ◽  
Nano Particles ◽  
Nano Composite

scholarly journals Space Charge Characteristics and Electrical Properties of Micro-Nano ZnO/LDPE Composites

Crystals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 481
Author(s):  
Jun-Guo Gao ◽  
Xia Li ◽  
Wen-Hua Yang ◽  
Xiao-Hong Zhang
Keyword(s):  
Electrical Properties ◽  
Space Charge ◽  
Synergistic Effects ◽  
Nano Particles ◽  
Breakdown Field ◽  
Nano Composite ◽  
Nano Zno ◽  
Additive Particles ◽  
Ldpe Composites ◽  
Short Connection

The synergistic effects of zinc oxide (ZnO) Micro/Nano particles simultaneously filled in low-density polyethylene (LDPE) on the space charge characteristics and electrical properties has been investigated by melt blending micro-scale and nanoscale ZnO additive particles into LDPE matrix to prepare Micro-ZnO, Nano-ZnO, and Micro-Nano ZnO/LDPE composites. The morphological structures of composite samples are characterized by Polarizing Light Microscopy (PLM), and the space charge accumulations and insulation performances are correlated in the analyses with Pulse Electronic Acoustic (PEA), DC breakdown field strength, and conductance tests. It is indicated that both the micro and nano ZnO fillers can introduce plenty of heterogeneous nuclei into the LDPE matrix so as to impede the LDPE spherocrystal growth and regularize the crystalline grains in neatly-arranged morphology. By filling microparticles together with nanoparticles of ZnO additives, the space charge accumulations are significantly inhibited under an applied DC voltage and the minimum initial residual charges with the slowest charge decaying rate have been achieved after an electrode short connection. While the micro-nano ZnO/LDPE composites acquire the lowest conductivity, the breakdown strengths of the ZnO/LDPE nanocomposite and micro-nano composite are, respectively, 13.7% and 3.4% higher than that of the neat LDPE material.

MAGNETIC RESISTIVITY IN Bi2Sr2Ca(Cu1-xCox)2Od EPITAXIAL THIN FILMS

2007 ◽  
Vol 21 (01) ◽  
pp. 127-132
Author(s):  
T. R. YANG ◽  
G. ILONCA ◽  
V. TOMA ◽  
P. BALINT ◽  
M. BODEA
Keyword(s):  
Magnetic Field ◽  
Thin Films ◽  
Activation Energy ◽  
Glass Transition ◽  
Effective Activation Energy ◽  
Epitaxial Thin Films ◽  
Effective Activation ◽  
High Quality ◽  
Plastic Deformations ◽  
Magnetic Resistivity

The scaling behavior of the effective activation energy of high-quality epitaxial c-oriented Bi 2 Sr 2 Ca ( Cu 1-x Co x)2 O d thin films with 0≤x ≤0.025 has been studied as a function of temperature and magnetic field. For all samples, the effective activation energy scales as U(T, μoH)=Uo(1-T/T c )mHn with exponent m=1.25±0.03, n=-1/2 and the field scaling 1/μoH and -UμoH for thick films and ultra thin films, respectively. The results are discussed taking into account of the influence of the Co substitution with a model in which U(T, H) arises from plastic deformations of the viscous flux liquid above the vortex-glass transition temperature.

Experimental investigation of electrodeposited Ni-Al2O3/ZrO2 nano composite on HSLA ASTM A860 alloy

2021 ◽  
Author(s):  
Chandrasekhara Sastry Chebiyyam ◽  
Pradeep N ◽  
Shaik AM ◽  
Hafeezur Rahman A ◽  
Sandeep Patil
Keyword(s):  
Grain Size ◽  
Corrosion Resistance ◽  
Composite Coating ◽  
Base Alloy ◽  
Composite Coatings ◽  
Nano Particles ◽  
Alloy Sample ◽  
Nano Composite ◽  
Nano Coating ◽  
Nano Composite Coating

Abstract Nano composite coatings on HSLA ASTM A860 alloy, adds to the barrier efficacy by increase in the microhardness, wear and corrosion resistance of the substrate material. Additionally, reduction of delamination of the nano composite coating sample is ascertained. Ball milling is availed to curtail the coating samples (Al2O3/ZrO2) to nano size, for forming a electrodeposited product on the substrate layer. The curtailment in grain size was ascertained to be 17.62% in Ni-Al2O3/ZrO2 nano composite coating. During the deposition process, due to the presence of Al2O3/ZrO2 nano particles an increase in cathode efficiency is ascertained. An XRD analysis of the nano composite coating indicates a curtailment in grain size along with increase in the nucleation sites causing a surge in the growth of nano coating layer. In correlation to uncoated HSLA ASTM A36 alloy sample, a surge in compressive residual stress by 47.14%, reduction of waviness by 32.14% (AFM analysis), upsurge in microhardness by 67.77% is ascertained in Ni-Al2O3/ZrO2 nano composite coating. Furthermore, in nano coated Ni-Al2O3/ZrO2 composite a reduction is observed pertaining to weight loss and friction coefficients by 27.44% and 13% in correlation to plain uncoated alloy respectively. A morphology analysis after nano coating indicates, Ni-Al2O3/ZrO2 particles occupy the areas of micro holes, reducing the wide gaps and crevice points inside the matrix of the substrate, enacting as a physical barrier to upsurge the corrosion resistance by 67.72% in correlation to HSLA ASTM A860 base alloy.

The activation energy and fragility index of the glass transition in Se76Te21Sb3 chalcogenide glass

2013 ◽  
Vol 574 ◽  
pp. 73-78 ◽  
Author(s):  
A.S. Soltan ◽  
A.A. Abu-Sehly ◽  
A.A. Joraid ◽  
S.N. Alamri
Keyword(s):  
Activation Energy ◽  
Glass Transition ◽  
Chalcogenide Glass ◽  
Fragility Index

Directly Synthesis of Polymeric Nano-Composite from Waste Solid Absorbents of Treating Styrene Monomer-Containing Waste Gas

2009 ◽  
Vol 610-613 ◽  
pp. 61-63
Author(s):  
Wu Jang Huang ◽  
Ling Yin Chang ◽  
Hsiu Hsien Wu ◽  
Yan Jia Liou
Keyword(s):  
Particle Size ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Nano Materials ◽  
Tio2 Powder ◽  
Nano Composite ◽  
Waste Gas ◽  
Styrene Monomer ◽  
Waste Solid

This study aimed to synthesize polystyrene (PS)-TiO2 nano-composite from the waste solid absorbent directly, so that the waste TiO2/PS solid absorbent could be used as nano-materials. TiO2 powder with a particle size of 12 nm was used for the solid absorbent. The TiO2 packed scrubbing tube was used for treating synthetic waste gas that contained styrene monomer. Experimental results confirmed that the concentrations of styrene in synthetic waste gas can be reduced by 62% after the activation of photocatalyst, and the lifetime of activated TiO2 catalyst is over 2 hours. From the NMR and DSC spectra of obtained products, PS is actually grafted on the surface of TiO2. The glass transition temperature of obtained PS in TiO2/PS solid absorbent is 100oC.

Cutting Performance and Wear Mechanisms of an Al2O3-Based Micro-Nano-Composite Ceramic Tool

2010 ◽  
Vol 443 ◽  
pp. 244-249 ◽  
Author(s):  
Yong Hui Zhou ◽  
Jun Zhao ◽  
Xing Ai
Keyword(s):  
Failure Modes ◽  
Cutting Tools ◽  
Tool Material ◽  
Composite Ceramic ◽  
Cutting Performance ◽  
Nano Particles ◽  
Ceramic Tool ◽  
Nano Composite ◽  
Micro Particles ◽  
1045 Steel

An Al2O3-based composite ceramic cutting tool material reinforced with (W, Ti)C micro-particles and Al2O3 micro-nano-particles was fabricated by using hot-pressing technique, the composite was denoted as AWT. The cutting performance, failure modes and mechanisms of the AWT micro-nano-composite ceramic tool were investigated via continuous turning of hardened AISI 1045 steel in comparison with those of an Al2O3/(W, Ti)C micro-composite ceramic tool SG-4 and a cemented carbide tool YS8. Worn and fractured surfaces of the cutting tools were characterized by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results of continuous turning revealed that tool lifetime of the AWT ceramic tool was higher than that of the SG-4 and YS8 tools at all the tested cutting speeds. The longer tool life of the AWT composite ceramic tool was attributed to its synergistic strengthening/toughening mechanisms induced by the (W, Ti)C micro-particles and Al2O3 nano-particles.

Trapezoidal traction–separation laws in mode II fracture in nano-composite and nano-adhesive joints

2018 ◽  
Vol 37 (11) ◽  
pp. 780-794 ◽  
Author(s):  
P Ghabezi ◽  
M Farahani
Keyword(s):  
Experimental Investigation ◽  
Data Reduction ◽  
Beam Theory ◽  
Calibration Method ◽  
Adhesive Joints ◽  
Nano Particles ◽  
Mode Ii ◽  
Nano Composite ◽  
Mode Ii Fracture ◽  
Beam Method

The main focus of this paper is on the experimental investigation and comparison between different bridging laws. For mode II fracture in the presence of nano-particles, these laws are calculated from three data reduction schemes for describing the bridging zone and trapezoidal traction–separation law parameters. For the calculation of the energy release rate in mode II fracture, three corresponding data reduction schemes, compliance calibration method, corrected beam theory and compliance-based beam method, have been utilized for different percentages of nano-particles in the adhesives and the adherents.

Study on the Crystallization Activation Energy of Poly (L-lactic acid) Nucleated with P-tert-butylcalix[8]arene

2018 ◽  
Vol 26 (2) ◽  
pp. 169-175
Author(s):  
Yaoqi Shi ◽  
Liang Wen ◽  
Zhong Xin
Keyword(s):  
Activation Energy ◽  
Lactic Acid ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Crystallization Temperature ◽  
Nucleating Agent ◽  
Crystallization Activation Energy ◽  
Temperature Range ◽  
Chain Mobility

The crystallization activation energy (Δ E) of a polymer comprises the nucleation activation energy Δ F and the transport activation energy Δ E*. In this paper, the Δ E of poly (L-lactic acid) (PLLA) nucleated with nucleating agent p- tert-butylcalix[8]arene (tBC8) was calculated. The results showed that the Δ E of nucleated PLLA was 165.97 kJ/mol, which is higher than that of pure PLLA. The reason why Δ E of PLLA increased when incorporating nucleating agent was studied. The increment of glass transition temperature ( Tg) for nucleated PLLA revealed that the polymer chain mobility was restricted by tBC8, which was considered as the reason for the increase of Δ E*. Further, polyethylene glycol (PEG) was added to improve the chain mobility, thus eliminated the variation of the transport activation energy Δ E* caused by tBC8. Then the effect of the increment of crystallization temperature range on the increase of Δ F was also taken into consideration. It was concluded that both decreasing the mobility of chain segments and increasing the crystallization temperature range caused an increase of Δ E for PLLA/tBC8.

Glass transition in polymers: (In)correct determination of activation energy

Polymer ◽  
2013 ◽  
Vol 54 (5) ◽  
pp. 1504-1511 ◽  
Author(s):  
Roman Svoboda ◽  
Jiří Málek
Keyword(s):  
Activation Energy ◽  
Glass Transition ◽  
Correct Determination
Sign in / Sign up

Export Citation Format

Share Document