Structural alterations of polycarbonate/PBT by gamma irradiation for high technology applications

In this work, polycarbonate/polybutylene terephthalate (PC/PBT) was irradiated with different gamma doses ranging from 200 kGy to 1950 kGy. Structural alterations of irradiated PC/PBT polymer blend have been studied using UV–vis spectroscopy, X-ray diffraction, and Fourier transform infrared (FTIR), as well as surface wettability. The results of UV–vis spectra showed that gamma irradiation induced an increase in the optical absorption with an increase in the gamma doses with shift in the optical absorption edge in the irradiated samples toward the higher wavelength. This shift is correlated with the decrease in optical band gap energy. Optical band gap decreases up to 12 and 20% with respect to pristine sample for direct and indirect transition, respectively. The number of carbon atoms per conjugated length has been estimated. The α phase and β phase of the crystalline PBT structure were observed. The α phase reflections are slightly increased due to the irradiation but the accompanying α to β transformation alters the results. FTIR investigation showed slight variation in the absorption spectrum specially in the range from 1300 to 1001 cm^?1 which are related to the O–C–O arrangements that is found to be the most affected part of the molecule by irradiation. A remarkable increase was observed in the wettability, surface free energy, and adhesion work of irradiated samples with an increase in the gamma doses.     

Variation of lexan polycarbonate properties by electron beam

The modifications in microstructural, optical, and photoluminescence properties of the Lexan polycarbonate (bisphenol‐A‐polycarbonate) films exposed to different electron doses have been studied using UV–vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), positron annihilation lifetime spectroscopy, photoluminescence spectroscopy, and scanning electron microscopy (SEM). The obtained UV–vis spectroscopy results showed decrease in optical energy gap, optical activation energy, and increase in number of carbon atoms per cluster with increase in electron dose. The chemical changes in electron irradiated polymers due to chain scission and reconstruction have been observed from FTIR spectroscopy. The correlation of positron lifetime study with optical measurement is obtained, and electron irradiation‐induced microstructural modifications within the polymer is understood. SEM result shows the degradation of Lexan polymer after electron irradiation. The mechanical properties and average molecular weight of Lexan decrease after irradiation, whereas average number of chain scissions per original polymer molecule increases. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Effects of ionizing radiation in ethylene-vinyl alcohol copolymers and in composites containing microfibrillated cellulose

This study reports on the effect of gamma radiation on morphological, thermal, and water barrier properties of pure ethylene vinyl alcohol copolymers (EVOH29 and EVOH44) and its biocomposites with the nanofiller microfibrillated cellulose (2 wt %). Added microfibrillated cellulose (MFC) preserved the transparency of EVOH films but led to a decrease in water barrier properties. Gamma irradiation at low (30 kGy) and high doses (60 kGy) caused some irreversible changes in the phase morphology of EVOH29 and EVOH44 copolymers that could be associated to crosslinking and other chemical alterations. Additionally, the EVOH copolymers and the EVOH composites reduced the number of hygroscopic hydroxyl functionalities during the irradiation processing and novel carbonyl based chemistry was, in turn, detected. As a result of the above alterations, the water barrier properties of both neat materials and composites irradiated at low doses were notably enhanced, counteracting the detrimental effect on water barrier of adding MFC to the EVOH matrix. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Effect of gamma rays on the structural and optical properties of a new hybrid monolith silica sucrose xerogel

A new hybrid monolithic silica xerogel containing sucrose has been synthesized via the sol–gel method. The resulting sucrose silica xerogels were exposed to gamma radiation with a dose in the range of 10–100 kGy. The effect of gamma rays on the physical and structural properties of sucrose silica xerogels was investigated by Fourier transform infrared spectroscopy (FTIR) and UV visible spectroscopy. The results of FTIR spectroscopy show that the irradiation process causes changes in the network's structure by inducing defects. The UV visible spectra present three main band defects; E′ center, Non-Bridging Oxygen Hole center (NBOHC) and carbonyl radicals in irradiated sucrose silica xerogel samples. Additionally, the results show that the values of optical band gap energy depend on irradiation. Therefore, generated defects suggest that the behavior of sucrose silica xerogels was modified from an insulator (Eg=5.82 eV) to a semiconductor (Eg=3.16 eV) under gamma irradiation.     

Formation of blisters in kapton polymer by the effect of 1.25 MeV gamma irradiation

The surface morphology, chemical, optical, and structural response of 1.25 MeV gamma rays irradiation at various doses ranging from 16 to 300 kGy on Kapton polymer samples were studied by using scanning electron microscope (SEM), Fourier Transform Infrared (FTIR), ultraviolet/visible absorption (UV/VIS) and X‐ray diffraction (XRD). The morphology study shows the blisters formation on the Kapton polymer surface due to 1.25 MeV gamma rays irradiation at ambient temperature. This observation provides a basis for the quantitative evaluation of FTIR results obtained for thermally stable polymer on the chemical bond deterioration with increasing gamma irradiation. The blistering mechanism is correlated with the internal gases (CO, H₂) released due to gamma radiation induced damages. The recorded UV–VIS spectrum shows a maximum absorption around the wavelength 540 nm. However, the nature of the spectra does not change due to gamma irradiation but a shift in absorption edge towards the higher wavelength side has been observed with increasing dose. The optical data shows an increase in the calculated band gap at the highest dose. The diffraction pattern of virgin sample shows that polymer is semicrystalline, but due to irradiation, a decrease in the peak intensity and FWHM and an increase in the crystallite size at the highest dose level of 300 kGy have been observed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Mechanical and thermal properties of polyvinylchloride/olive residue flour blends treated by gamma irradiation

In this study, gamma irradiation treatments were used to improve the compatibility between poly(vinyl chloride) (PVC) and olive residue flour (ORF). The blends were subjected to gamma irradiation at doses of 10 and 70 kGy. The mechanical, thermal, and morphological behaviors of those blends have been assessed. The irradiated blends exhibit better thermal properties, higher tensile modulus, elongation, and strength at break than those of unirradiated blends. The contact angle of water on the surface of a blend irradiated at doses of 10 and 70 kGy is smaller than that for their corresponding unirradiated blend. These treatments cause surface oxidation of PVC/ORF films, as revealed by Fourier transform infrared (FTIR) spectroscopy analysis. J. VINYL ADDIT. TECHNOL., 22:273–278, 2016. © 2014 Society of Plastics Engineers     

Characterization of UV-irradiated Lexan polycarbonate films

Lexan polycarbonate films were irradiated by UV radiation at wavelength $ \lambda $  = 250 nm under different time exposures of 1, 2, 4, 6 and 7 h. Structural, optical and mechanical modifications were studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), UV–Visible spectroscopy, impedance analysis, tensile testing and rheometry methods. The crystallite size and percentage of crystallinity were found to decrease upon irradiation as was studied by XRD. It indicated that polymer was moving towards more disordered state after irradiation corroborating DSC results. FTIR Study showed the carbonate linkage is the radiation-sensitive linkage and benzene ring does not undergo any change after irradiation. SEM results showed the formation of pores after irradiation. The atomic force microscopy measurements revealed that the average roughness of the film increased after being irradiated. The glass transition temperature was observed to decrease after irradiation as revealed by DSC measurement. UV–Visible spectra showed decrease in optical band gap after irradiation due to chain scission in the Lexan polycarbonate. Plot of AC conductivity versus log (f) displayed a sharp increase in conductivity at higher frequencies and dielectric constant/loss was observed to change with the irradiation time. The mechanical properties and average molecular weight of Lexan polycarbonate decreased after irradiation, while the average number of chain scissions per original polymer molecule increased with increase in time of exposure.     

Enhancement of fluorine doped amorphous carbon thin films from microwave surface wave plasma activated above room temperature

Fluorinated amorphous carbon (a-C:F) thin films were synthesized above room temperature by microwave surface wave plasma chemical vapour deposition (MW SWP CVD). The effect of deposition temperature on optical, electrical, chemical and bonding properties of the a-C:F films were studied by ultraviolet–visible spectroscopy (UV–VIS), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectrometry (XPS), Raman spectrometry and TEM measurements. The film exhibits high transparency and decrease in optical band gap with increasing deposition temperature. FTIR study shows the increase in CC and decrease in C–Fx bonds of the films with increasing deposition temperature. Raman study shows some important structural changes in the films due to fluorine incorporation. XPS result shows the shift of carbon peak to higher binding energy due to carbon fluorine link to the films. TEM shows the increasing graphitic layer in the films with increasing deposition temperature.     

Optical Energy Estimation of Irradiated Polypropylene

The optical absorption has been studied under exposure to gamma radiation. Thin films of polypropylene were irradiated with a ⁶⁰Co source and doses ranged up to 6 kGy. Analysis of the optical absorption spectra indicated that both direct and indirect electron transitions take place in the polymer. The observed optical energy gap (E_opt) and energy gap-tail (ΔE) for irradiated films were determined from the measured absorption spectra. The average values of (E_opt) and (ΔE) are 5.85 eV and 0.5 eV, respectively. There is no detectable change in the optical energy gaps and tails under the applied gamma-ray doses.     

The irradiation impacts of high gamma doses on optical features and degradation of Makrofol DE 1-1

The induced impacts of high doses of gamma irradiations on the optical features of the Makrofol DE 1-1 detector were studied in the ultraviolet and visible range (from 270 to 500 nm). Makrofol DE 1-1 detector specimens were irradiated separately for different doses from 200 to 1000 kGy; step 200. The optical absorbance spectra of the pristine Makrofol DE 1-1, as well as the irradiated gamma-ray samples display two main features: (i) A redshift with further gamma-ray irradiation doses from 200 to 1000 kGy. This redshift can be ascribed to irradiation-induced defects in polymer material. (ii) A remarkable increment in the optical absorbance for irradiated Makrofol DE 1-1 specimens compared to the pristine one. This increment can be ascribed to the creation of some electronic levels within the forbidden gap resulting from the irradiation process. Moreover, this absorbance increment was employed to assess the degradation percent produced by gamma-ray irradiations. The degradation percent of the Makrofol DE 1-1 increased from 31.73% at 200 kGy to 78.08% at 1000 kGy. The optical band gap, Fermi level and metallization criterion showed decrement behaviors with further doses of gamma-ray irradiations. Also, the percent of changes in optical band gap values were employed to evaluate the degradation of Makrofol DE 1-1 under gamma-ray irradiations. This percent augmented from 15.19% at 200 kGy to 20.25% at 1000 kGy proving the obvious degradation of Makrofol DE 1-1 under gamma-ray irradiations. On the other hand, the number of carbon atoms per cluster, linear and nonlinear refractive indices showed increasing behaviors with further doses of gamma-ray irradiations.     

A comparative study of gamma and ultraviolet radiation on gelatin film with 2-ethylhexyl acrylate

Gelatin films were prepared from gelatin granules in an aqueous medium by casting. Tensile strength (TS) and elongation at break (Eb%) of the films were found to be 29.2?MPa and 4.9%, respectively. Gelatin films were irradiated under gamma and UV radiation with different doses. Gamma treated gelatin films showed higher TS and Eb% over untreated ones, and even higher than that of the UV treated films. A series of gelatin solutions (formulations) was prepared by blending varying percentages (2–10% by wt) of 2-ethylhexyl acrylate (EHA) and then the films were prepared. Some EHA-blended gelatin films were irradiated under gamma radiation at various doses (50–500?krad) and other films were cured under UV radiation at different intensities (10–30 UV passes). EHA-blended?+?gamma treated gelatin films showed the highest mechanical properties than that of the EHA-blended?+?UV treated films. The degradation properties present in the soil were determined for the pure and treated films. It was observed that EHA-blended?+?gamma treated gelatin film degrades more than that of the EHA-blended?+?UV treated films.     

Effects of an oxygen‐ion beam (O+7, 100 MeV) and γ irradiation on polypyrrole films

Nanostructured polypyrrole films doped with para‐toluene sulfonic acid were prepared by an electrochemical process, and a comparative study of the effects of swift heavy ions and γ‐ray irradiation on the structural and optical properties of the polypyrrole was carried out. Oxygen‐ion (energy = 100 MeV, charge state = +7) fluence varied from 1 × 10¹⁰ to 3 × 10¹² ions/cm², and the γ dose varied from 6.8 to 67 Gy. The polymer films were characterized by X‐ray diffraction, ultraviolet–visible spectroscopy, and scanning electron microscopy. The X‐ray diffraction pattern showed that after irradiation, the crystallinity improved with increasing fluence because of an increase in the crystalline regions dispersed in an amorphous phase. The ultraviolet–visible spectra showed a shift in the absorbance edge toward higher wavelengths, which indicated a significant decrease in the band gap of the polypyrrole film after irradiation. The scanning electron microscopy study showed a systematic change in the surface of the polymer. A similar pattern was observed with the γ irradiation. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Engineering of morphological,optical, structural,photocatalytic and catalytic properties of nanostructured CuO thin films fabricated by reactive DC magnetron sputtering

Nanostructured thin films of CuO were deposited on silica glass substrates using reactive DC magnetron sputtering technique. Microstructural, morphological, optical, catalytic and photocatalytic properties of the prepared CuO thin films were examined using FESEM, AFM, Rutherford backscattering spectrometry, XRD, XPS, UV–Vis absorption and PL spectroscopy. FESEM showed nanostructures in the thin films, which were confirmed to be of monoclinic CuO by XRD analysis. Substrate temperature variation (40 °C, 100 °C and 300 °C) was found to significantly alter the optical, morphological, photocatalytic and structural properties of the CuO nanostructured thin film coatings. FESEM and AFM analyses showed decrease in size of nanostructures and surface roughness increase with increase in substrate temperature. Increase in UV–Vis absorbance and PL intensity of CuO thin films with decrease in crystallite size were noticed as the substrate temperature was increased. The prepared nanostructured CuO thin films exhibited highly enhanced photocatalytic activities and degraded dyes (MB and MO) in water in just 40 min under solar exposure and catalytic transformation of 4-nitrophenol (4-NP) took place in just 15 min. The developed CuO nanostructured thin film coatings are very promising for large scale, practical and advanced catalytic reduction of toxic 4-NP and photocatalytic applications in solar driven water purification.     

UV-Visible and IR Spectroscopic Studies of Gamma Irradiated Transition Metal Doped Lead Silicate Glasses

Lead silicate (LS) glasses of the basic composition PbO 75%, SiO₂ 25% together with samples containing (∼0.1%) of transition 3d metal oxides (Ti→Cu) were prepared. UV/VIS optical analysis for as prepared and after successive gamma irradiated samples were used to shed more light on the structural modifications that occur due to different dopants and different irradiation doses. The UV-Vis. spectral analysis for undoped glass shows induced absorption bands at 205–400 nm which are assumed to be correlated with the base host glass and dopant transition metal ion doped glasses and dose of irradiation. The positions of the bands are observed to change slightly by gamma irradiation due to the combined effect of induced defects from the host base glass or the transition metal added. Gamma irradiation is observed to cause a decrease in the intensities of the IR absorption bands of the prepared samples accompanied by losing sharpness. These features are related to more amorphicity or disorder by irradiation or to the possible changes in bond angle or bond length in the building groups arrangement.     

Gamma rays Interactions with Bismuth Phosphate Glasses Doped with 3d Transition Metal Oxides

Bismuth phosphate glasses of the basic composition (Bi₂O₃ 30 mol%-P₂O₅ 70 mol%) with additional dopants 3d TM oxides (0.2 wt%) were prepared by the melting and annealing technique. Combined optical (UV/vis.) and FT infrared absorption spectra were measured for the prepared samples before and after gamma irradiation with a dose of 8 Mrad (8×10⁴ Gy). Optical spectra reveal strong UV absorption bands due to trace iron impurity together with an additional absorption band due to Bi³⁺ beside characteristic absorption related to specific 3d TM ions with preference for the lower valences due to the reducing effect of phosphate host glass. FTIR spectra show vibrational bands due to phosphate chains with the sharing of absorption bands due to Bi-O vibrations. Gamma irradiation causes limited changes due to the presence of heavy metal Bi³⁺ ions which show some shielding behavior towards gamma irradiation as revealed by optical and FT infrared absorption measurements. Some suggested photochemical reactions are forward to interpret the changes in the UV spectra beside the formation of an induced phosphorus oxygen hole center (POHC) in the visible region.

     

Influence of UV stabilizers on the weathering of PETG and PCTT films

The influence of two UV photostabilizers on the photostability of Polyethylene-co-CHDM-terephthalate (PETG) and Polycyclohexylenedimethylene-Co-TMCD-terephthalate (PCTT) copolyester films was investigated. Untreated films and films containing stabilizer were irradiated. The resulting films were analyzed by attenuated total reflectance Fourier transform infrared (ATR FTIR) spectroscopy, gel permeation chromatography (GPC), and X-ray photoelectron spectroscopy (XPS). FTIR spectra of the irradiated films containing Cyasorb 1164 showed less change in intensity of the broad peak corresponding to OH groups, than the films containing Cyasorb 3638, indicating that Cyasorb 1164 is a better photostabilizer for these films. XPS results showed that the decrease in C/O ratio, due to photodegradation, was greater in films containing Cyasorb 3638 compared to those containing Cyasorb 1164. The formation of degradation products was evident from emission spectra arising from extracts of irradiated films based on PCTT +10% Cyasorb 3638, but no degradation products were apparent in extracts from irradiated PCTT +10% Cyasorb 1164. UV-absorption spectra of Cyasorb 1164 overlap more substantially with the absorption spectra of PETG and PCTT. The results from FTIR, XPS, and GPC analyses of the irradiated PETG and PCTT films demonstrated that Cyasorb 1164 was more effective than Cyasorb 3638 in enhancing resistance to UV-induced weathering. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48198.     

Structural changes on the surfaces of borosilicate glasses induced by gamma-ray irradiation

Vitrification is a kind of glass that can solidify high-level radioactive waste (HLW). As the basic material of vitrification, borosilicate glass was studied extensively. To keep HLW away from the biosphere, the tolerance of borosilicate glass to irradiation is important. In this work, various samples of borosilicate glass with different compositions were irradiated with gamma rays at ambient temperature to study their stability. The hardness, moduli, and microscopic changes on surfaces of the borosilicate glasses were measured at specific absorbed doses. Upon the gamma irradiation, the structural changes on surfaces of borosilicate glasses were identified, which were strongly influenced by the composition of borosilicate glasses. The results demonstrate that gamma irradiation, as well as beta irradiation, might strongly influence the properties of vitrification. The irradiation effects on vitrification induced by gamma irradiation should be paid more attention to than before.     

Monitoring of the discoloration on γ‐irradiated PE and EVA films to evaluate antioxidant stability

γ‐Irradiated films could provoke unexpected interaction with proteins for instance just after irradiation and not necessarily after 12 months indicating there is no more reactive species. The optical properties of two multilayer films [polyethylene (PE)/ethylene vinyl alcohol (EVOH)/PE and ethylene vinyl acetate (EVA)/EVOH/EVA] after different γ‐irradiation doses is then studied in this work. The investigation on these films, either non‐irradiated or γ‐irradiated (up to 270 kGy), is performed by colorimetry measurement over time (up to 12 months) to assess the generation of new species inside the materials. The color change is directly correlated with absorbed γ‐doses. Over time, the color decreases and goes back to its initial time level. This discoloration evolution could be therefore used as an indication of the completion of the generated species reactions induced by γ‐irradiation. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46114.     

Effect of PMMA addition on characterization and morphology of PVDF

Polyvinylidene fluoride and polymethylmethacrylate (PVDF/PMMA) films were blended with different concentrations by casting method. Structural, spectroscopic, and morphological characteristics of both the interface and the surface of the films have been investigated. The blends were characterized using X‐ray diffraction (XRD), Fourier transform infrared (FTIR), UV–visible, differential thermal analysis (DTA), and scanning electron microscopy (SEM). All measurements reveal that the blends take place based on the influence of PMMA content on PVDF. FTIR results indicate the possible interactions between carbonyl group of PMMA and CH₂ groups of PVDF which indicates the formation of blends. Optical absorption spectra suggested the presence of an optical gap (E_g) which decreased with increasing PMMA content. UV/VIS spectra were characterized by a sharp edge and a window of wavelength range 290–350 nm for some blends. The optical window can be used as an optical sensor or band pass filter. The degree of crystallinity was found to decrease with increasing PMMA content, which was confirmed by XRD and DTA analysis. SEM micrograph shows spherulites which increase with the addition of PMMA and it becomes sharper and contains a longitudinal shape. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

Effect of Gamma Irradiation on Structural and Optical Investigations of Borosilicate Glass Doped Yttrium Oxide

The structural, physical, and optical properties of prepared glass samples of the composition formula 30SiO₂-(40-x)B₂O₃-20Na₂O-10Al₂O₃-xY₂O₃, where x = 0, 1, 5, 7 (wt%) were studied before and after gamma irradiation using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and UV-visible spectroscopy. The optical absorption spectra of study glasses were recorded in the UV/visible range of 200–900 nm. The optical band gap energies were calculated from absorption data. These results show that E_opt decreases with increasing concentration of Y₂O₃. The changes occurring in the optical parameters obtained from absorption spectra before and after irradiation have been referred to irradiation induced structural defects and compositional changes.