Purpose - The purpose of this paper is to research the durability of the adhesive-poly(ethylene terephthalate) film joints.Design methodology approach - The adhesive-poly(ethylene terephthalate) ...joints are prepared with poly ethylene terephthalate film synthesised from thioglycolic acid, terpene hydrocarbon resin and acetone resolution at room temperature. These joints are characterised by methods of peel strength tests, energy dispersive X-ray spectroscopy (EDX) and analysis of glass transition temperature (Tg) to examine their durability.Findings - Peel strength tests and EDX analyses prove that water diffusion in different humidity aging conditions causes similar changes, namely having the time-temperature equivalence at 45°C for 200, 300, 500 and 600 h, respectively, almost corresponding with those at 55°C for 100, 200, 300 and 400 h, respectively, and at 65°C for 50, 100, 150 and 200 h, respectively. The changes in EDX spectra of adhesive-poly(ethylene terephthalate) film joints indicate that the rate of water penetration in the adhesive is faster than that in the poly(ethylene terephthalate) film. In humidity aging process, the decline ratio of peel strength of adhesive-poly(ethylene terephthalate) film joints treated with Co60 irradiation is lower than that treated with acetone washing or chemical treatment.Originality value - The paper shows that using EDX for analysis of durability of adhesive film joints is of significance to industrial process.
Indium oxide In2O3 and silicon oxide SiO mixtures in the form of thick films pnjunctions were investigated for gamma radiation dosimetry purposes. Polymer pastes of In2O3 and SiO mixtures in various ...proportions were made of 92 wt per cent of functional material and 8 wt per cent of PVB, while ethyleneglycolmonobutylether was used as a solvent. Raman spectroscopy and Xray diffraction XRD of the films readily endorse the formation of a mixed silicon oxide and indium oxide coating. All devices were exposed to a disctype 137Cs source with an activity of 370kBq. The IV characteristics for the samples were measured after each exposure dose. Results show that the current is increased with the increase in radiation dose to a certain level, exceeding this level resulted in unstable dosimetric characteristics and device damage. The performance parameters of the devices, such as sensitivity to radiation exposure and working dose region, were found to be highly dependant on the composition of the materials used.
Purpose - The purpose of this paper is to evaluate the photochromic performance of photochromic compounds in polymer matrices.Design methodology approach - The poly(methyl methacrylate) PMMA and ...epoxy resin doped with photochromic spirooxazine (SO) are prepared and the effects of ultraviolet (UV) irradiation are studied using spectrophotometer. The reversible reaction is effected using white light. Photochemical fatigue resistance of these films is also studied.Findings - Irradiation of colourless 7′,8′-dichloro-1,3,3-trimethylspiroindoline-2,3′-3Hbenzob1,4oxazine (SO) doped in PMMA and epoxy resin with UV light (366 nm) results in the formation of an intense purple-red coloured zwitterionic photomerocyanine (PMC). The reverse reaction is photochemically induced by irradiation with white light. Photocolouration and photobleaching reactions follow a first-order rate equation. It is found that photocoloration rate constant of (SO) in both matrices is almost the same, which is unexpected. On the other hand, the rate of photobleaching reaction of (PMC) in PMMA is twice slower than that in the epoxy resin. It seems that the presence of the two chlorine atoms at positions 7′ and 8′ of the benzooxazine moiety destabilise the PMC in epoxy resin film and results in speeding up the fading process compared to that in PMMA. SO doped in epoxy resin shows much better fatigue resistance than that doped in PMMA.Research limitations implications - The PMMA and epoxy resin polymers doped photochromic spirobenzooxazine described in this paper were prepared and studied. The principle of study established can be applied to any type of polymer or to any type of photochromic compounds.Practical implications - The photochromic materials developed can be used for different applications, such as coatings and holography.Originality value - The method developed may be used to enhance the performance of photochromic materials.
This potentially unique work offers various approaches on the implementation of nanowires. As it is widely known, nanotechnology presents the control of matter at the nanoscale and nanodimensions ...within few nanometers, whereas this exclusive phenomenon enables us to determine novel applications. This book presents an overview of recent and current nanowire application and implementation research worldwide. We examine methods of nanowire synthesis, types of materials used, and applications associated with nanowire research. Wide surveys of global activities in nanowire research are presented, as well.
Purpose - The purpose of this paper is to modify the surface property of polyacrylate latex films using only small amounts of fluorinated acrylate and to optimise the results of such a ...modification.Design methodology approach - The core-shell particles with polyacrylate rich in core and containing fluorinated polymer rich in shell are prepared by a two-stage semi-continuous emulsion polymerisation under kinetically controlled conditions. The surface properties of the latex films produced from the core-shell particles are investigated by optical goniometer measurement as well as contact angle method.Findings - The latex films produced from the core-shell particles exhibited surface energy of around 10 mN m. The angle resolved X-ray photoelectron spectrum measurements showed an increased average fluorine concentration in a surface layer thickness of a few nanometres, when compared to the fluorine concentration in the bulk.Research limitations implications - Methyl methacrylate, butyl acrylate and N-methylol acrylamide monomers are used as co-monomer to form the shell with fluoroalkyl methacrylate. By preparing core-shell emulsion with a fluoropolymer in the shell phase, the surface property of polyacrylate latex films is efficiently modified by using only small amounts of fluorinated acrylate monomer.Practical implications - The method developed provided a simple and practical solution to improving the surface property of polyacrylate latex films.Originality value - The method for enhancing surface property of polyacrylate latex films is novel and can find numerous applications in surface coating.
The opportunities for doing scattering experiments at synchrotron and neutron facilities have grown rapidly in recent years and are set to continue to do so into the foreseeable future. This text ...provides a basic understanding of how these techniques enable the structure and dynamics of materials to be studied at the atomic and molecular level. Although mathematics cannot be avoided in a theoretical discussion, the aim has been to write a book that most scientists will still find approachable. To this end, the first two chapters are devoted to providing a tutorial background in the mathematics and physics that are implicitly assumed in other texts. Thereafter, the philosophy has been one of keeping things as simple as possible.
Purpose - The purpose of this paper is to derive a dynamic equation for modelling the behaviour of smectic-C liquid crystals under the effect of an electric field.Design methodology approach - The ...model equation is solved using a finite difference approximation, method of lines and pseudo-spectral methods. The solutions are compared for accuracy and efficiency. Comparison is made of the efficiency of finite differences, method of lines and pseudo-spectral methods.Findings - The Fourier pseudo-spectral method is shown to be the most efficient approach.Originality value - This work is original; a computational comparison of numerical schemes applied to liquid crystals has not been found in the literature.
Purpose - Anisotropic conductive film (ACF) is now an attractive technology for direct mounting of chips onto the substrate as an alternative to lead-free solders. However, despite its various ...advantages over other technologies, it also has many unresolved reliability issues. For instance, the performance of ACF assembly in high temperature applications is questionable. The purpose of this paper is to study the effect of bonding temperatures on the curing of ACFs, and their mechanical and electrical performance after high temperature ageing.Design methodology approach - In the work presented in this paper, the curing degree of an ACF at different bonding temperatures was measured using a differential scanning calorimeter. The adhesion strength and the contact resistance of ACF bonded chip-on-flex assembly were measured before and after thermal ageing and the results were correlated with the curing degree of ACF. The ACF was an epoxy-based adhesive in which Au-Ni coated polymer particles were randomly dispersed.Findings - The results showed that higher bonding temperatures had resulted in better ACF curing and stronger adhesion. After ageing, the adhesion strength increased for the samples bonded at lower temperatures and decreased for the samples bonded at higher temperatures. ACF assemblies with higher degrees of curing showed smaller increases in contact resistance after ageing. Conduction gaps at the bump-particle and or particle-pad interfaces were found with the help of scanning electron microscopy and are thought to be the root cause of the increase in contact resistance.Originality value - The present study focuses on the effect of bonding temperatures on the curing of ACFs, and their adhesion strength and electrical performances after high temperature ageing. The results of this study may help the development of ACFs with higher heat resistance, so that ACFs can be considered as an alternative to lead-free solders.
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