Optical, Electronic, and Microstructural Properties of Polyethylene Terephthalate and Polyethylene Naphthalate Modified by 150 keV Mg + Ion Irradiation

The surfaces of poly(ethylene terephthalate) (PET) and poly(ethylene naphthalate) (PEN) were treated with an atmospheric-pressure oxygen and helium plasma. Changes in the energy, adhesion, and chemical composition of the surfaces were determined by contact angle measurements, mechanical pull tests, and X-ray photoelectron spectroscopy (XPS). Surface-energy calculations revealed that after plasma treatment the polarity of PET and PEN increased 6 and 10 times, respectively. In addition, adhesive bond strengths were enhanced by up to 7 times. For PET and PEN, XPS revealed an 18-29% decrease in the area of the C 1s peak at 285 eV, which is attributable to the aromatic carbon atoms. The C 1s peak area due to ester carbon atoms increased by 11 and 24% for PET and PEN, respectively, while the C 1s peak area resulting from C-O species increased by about 5% for both polymers. These results indicate that oxygen atoms generated in the plasma rapidly oxidize the aromatic rings on the polymer chains. The Langmuir adsorption rate constants for oxidizing the polymer surfaces were 15.6 and 4.6 s(-1) for PET and PEN, respectively.

Bis(hydroxyethyl)naphthalate (BHEN) was polymerized to polyethylenenaphthalate (PEN) in the presence of various metallic catalysts. The influence of the nature and concentration of these catalysts on the rate of polymerization has been investigated. The order of decreasing catalytic influence of various metal ions on the polymerization of BHEN was found to be: Ti > Sb > Zn > Co > Pb > Ni (Mg). The effect of the reaction temperature has also been studied. The optimal concentration of these catalysts and reaction temperature were found to be 30 × 10−5 (mol/mol B HEN) and 285°-293°C. Because of its insolubility in ordinary solvent, the molecular weight of PEN was measured using the light scattering method.

The present communication aims at considering the possibility to carry out electroluminescence (EL) measurements on insulating materials at variable temperature. For thermal regulation purpose, it is no longer possible to work under vacuum as we used to do, and thus measurements have been achieved with nitrogen gas in the ambient. The conditions for obtaining a stable signal under both AC and DC stress are described. We have considered an unsaturated polyester, poly(ethylene naphthalate), on which we have a reasonable background as regards EL features at room temperature. Changes in the EL signal are discussed based on the temperature dependencies of photoluminescence and transport properties of these materials.

Extending damage accumulation of commercial reactor irradiated 316 stainless steel with ion irradiation

Poly Ethylene Naphthalate (PEN) is an industrial polymer plastic which is investigated as a low background, transparent, scintillating and wavelength shifting structural material. PEN scintillates in the blue region and has excellent mechanical properties both at room and cryogenic temperatures. Thus, it is an ideal candidate for active structural components in experiments for the search of rare events like neutrinoless double-beta decay or dark matter recoils. Such optically active structures improve the identification and rejection efficiency of backgrounds events, like this improving the sensitivity of experiments. This paper reports on the production of radiopure and transparent PEN plates These structures can be used to mount germanium detectors operating in cryogenic liquids (LAr, LN). Thus, as first application PEN holders will be used to mount the Ge detectors in the Legend-200 experiment. The whole process from cleaning the raw material to testing the PEN active components under final operational conditions is reported.

Study of modifications in Lexan polycarbonate induced by swift O6+ ion irradiation

Carbon ion beam induced modifications of optical, structural and chemical properties in PADC and PET polymers

Estimation of optical band gap and carbon cluster sizes formed in heavy ion irradiated polycarbonate

The paper presents the results of investigations of mechanical and thermal properties of poly(ethylene naphthalate) and poly(ethylene terephtalate) blends. The elongation, tensile and impact strength, Brinell hardness and thermal properties has been presented in this paper. It has been observed that thermal resistance of the blends improves with the increase of PEN share in the blends. The mechanical properties show the small increase with increasing the PEN share in the blends, only the elongation of the PEN/PET blends shows a great increase to compare with PET. DSC study show that all blends have double glass transition and melting temperatures and allowed to determine the crystalinity of the blends.

Aiming to assess the feasibility of a one-step processing, comprising simultaneously the mixing of polymer/filler and the modification of the particle surface, we prepared composites of recycled poly(ethylene terephtalate) and micronized concrete waste particles, using an oligomerising agent. The goal was to partially oligomerise the recycled polymer and foster the chemical modification of the concrete particles surface with these oligomers, to improve the dispersion and adhesion of the filler in the polymeric matrix. The composites were evaluated by thermogravimetry/derivative thermogravimetry, differential scanning calorimetry, Fourier transform infrared spectroscopy, wide angle X-ray diffractometry and rheological measurements. There was an improvement in the crystallizing effect of the filler in the composites with oligomerised polymer. We noticed a trend of reaction between the citric acid and the poly(ethylene terephtalate) oligomer in the Fourier transform infrared spectroscopy results. From the wide angle X-ray diffractometry analysis we assessed that the presence of the filler had more influence in the crystallinity of the recycled poly(ethylene terephtalate) than the degradation caused by the citric acid. The rheological measurements showed an increased cohesion of the internal structure of the materials in the oligomerised samples. We conclude that there is a pathway to obtain composites of recycled poly(ethylene terephtalate) and surface-modified concrete waste particles in a single step, by partially oligomerising the polymer in the molten processing.

The problem of optical filters for soft x rays and extreme ultraviolet that provide a high degree of blocking ultraviolet and visible background radiations is considered. The subject of discussion is the filter based on a track membrane, a polymer film with micrometer and submicrometer pores, rather than the standard thin-film system. It is proposed that the membranes be made of poly(ethylene naphthalate) or polyimide, the UV absorption edge of which lies near the boundary of the visible range. The properties of poly(ethylene naphthalate) and polyimide membranes are contrasted with those of conventional porous poly(ethylene terephthalate) films, which are obtained by ion track etching. The spectral characteristics of poly(ethylene naphthalate) and polyimide films, as well as the formation of “track” pores when the specimens are successively treated by fast ions and chemicals, are studied. The basic parameters of the resulting porous structures are examined, and treatment conditions under which desired optical properties of the membranes are achieved are found. Filters based on poly(ethylene naphthalate) and polyimide track membranes may be applied in x-ray astronomy as constituents of detectors incorporated into solar telescopes and in experiments with the laboratory plasma.

Surface modification of PET membrane by ion implantation

Derived through liquid phase exfoliation, the irradiation response of nanoscale, exfoliated tin sulfide (SnS) systems are being reported in this work. The SnS nanosheets were exposed to 90[Formula: see text]MeV [Formula: see text] ion beams across fluences ranging from [Formula: see text] to [Formula: see text][Formula: see text]ions/cm2. With an electronic energy loss ([Formula: see text]) of [Formula: see text]56[Formula: see text]eV/Å, dominating over the nuclear energy loss ([Formula: see text]), the average crystallite size of the irradiated samples displayed an augment when compared to its pristine counterpart. Exhibiting an orthorhombic crystal structure, structural analyses of both pristine and irradiated samples were conducted via X-ray diffraction (XRD) technique. Raman analysis has manifested some modifications in the SnS nanosystem upon radiation exposure, particularly with higher fluences causing local structural disorder and amorphization of the material. Moreover, morphological changes in the irradiated SnS samples were examined using field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM), with AFM images revealing an increase in the root mean square (RMS) roughness corresponding to ion fluence. Furthermore, swift heavy ion (SHI) irradiation prompted a non-rectifying Ohmic [Formula: see text] characteristics and altered the electrical conductivity of the SnS nanosheets.

Surface Enhanced Raman Spectroscopy (SERS) is a powerful tool to amplify weak Raman signals by an increment of the apparent Raman cross-section of the analytes. The present work reports on ion beam synthesized SERS substrates. Thin films of Au were deposited on quartz substrate using ion beam sputtering. The films were further irradiated by 1.36 MeV Xe ions to a fluence of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">15</sup> and 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">16</sup> ion/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . Rutherford Backscattering (RBS) was performed for Au thin film deposited on quartz to evaluate the Au content. Thickness of the film was found to be -- 7.8nm by RBS. The FESEM was performed for pristine and irradiated samples which revealed the formation of separated distinguishable Au nanoparticles in irradiated samples. The UV-Visible spectroscopy was carried out for pristine and irradiated materials which indicated surface plasmon resonance due to the formation of Au nanoparticles after ion irradiation. The assessment of SERS was performed on High Resolution Raman using 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−4</sup> M di-nitro salicylic acid (DNSA) as a model analyte, which has a similar chemical structure to the commonly found explosives. The presence of NO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> group and aromatic ring stretching vibration were observed on the irradiated sample which were otherwise not observed on the pristine sample. Hence, this demonstrated ion beam synthesis of SERS substrate.

We have measured at room temperature (RT) the Fourier-transform infra-red (FTIR) absorption spectra of ion-irradiated thin epitaxial films of cubic silicon carbide (3C–SiC) with 1.1 µm thickness on a 500 µm thick (1 0 0) silicon wafer substrate. Irradiations were carried out at RT with 2.3 MeV 28Si+ ions and 3.0 MeV 84Kr+ ions for various fluences in order to induce amorphization of the SiC film. Ion projected ranges were adjusted to be slightly larger than the film thickness so that the whole SiC layers were homogeneously damaged. FTIR spectra of virgin and irradiated samples were recorded for various incidence angles from normal incidence to Brewster’s angle. We show that the amorphization process in ion-irradiated 3C–SiC films can be monitored non-destructively by FTIR absorption spectroscopy without any major interference of the substrate. The compared evolutions of TO and LO peaks upon ion irradiation yield valuable information on the damage process.Complementary test experiments were also performed on virgin silicon nitride (Si3N4) self-standing films for similar conditions. Asymmetrical shapes were found for TO peaks of SiC, whereas Gaussian profiles are found for LO peaks. Skewed Gaussian profiles, with a standard deviation depending on wave number, were used to fit asymmetrical peaks for both materials. A new methodology for following the amorphization process is proposed on the basis of the evolution of fitted IR absorption peak parameters with ion fluence. Results are discussed with respect to Rutherford backscattering spectrometry channeling and Raman spectroscopy analysis.