X-ray irradiation-induced changes in Bayfol DPF 5023 polycarbonate

Samples from sheets of the polymeric material Bayfol DPF 5023 have been exposed to X-ray radiation in the dose range 100–2300 Gy. The modifications induced in Bayfol samples due to X-ray irradiation have been studied through different characterization techniques such as X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, intrinsic viscosity, refractive index and color difference studies. The infrared spectroscopy indicated that crosslinking is the dominant mechanism at the dose range of 200–2300 Gy. The crosslinking reported by FTIR spectroscopy destroyed the degree of ordering in the Bayfol samples, as revealed by the XRD technique. Also, this crosslinking led to an increase in the value of intrinsic viscosity from 0.54 for the non-irradiated sample to 0.63 for the sample irradiated with 2300 Gy at 30 °C, indicating an increase in the average molecular mass. This was associated with an increase in the refractive index. Additionally, the non-irradiated Bayfol samples showed significant color sensitivity toward X-ray irradiation. This sensitivity appeared in the change of the blue color component of the non-irradiated Bayfol film to yellow after exposure to X-ray doses up to 2300 Gy. This is accompanied by a net increase in the darkness of the samples.     

Gamma induced changes in the structural and optical properties of Makrofol LS 1–1 polycarbonate

ABSTRACT

Samples from sheets of the polymeric material Makrofol LS 1–1 have been exposed to gamma radiation in the dose range 10–250?kGy. The modifications induced in Makrofol samples due to gamma irradiation have been studied through different characterization techniques such as intrinsic viscosity as a measure of the average molecular mass, Fourier Transform Infrared spectroscopy FTIR, refractive index and color difference studies. The results indicate that the crosslinking dominates at the dose range 50–250?kGy. The crosslinking reported by viscosity measurements is supported by the trend of the function groups present in the sample with the gamma dose. Also, the increase in intrinsic viscosity indicating an increase in the average molecular mass was associated with an increase in the refractive index. Additionally, the non-irradiated Makrofol samples showed significant color sensitivity towards gamma irradiation. The color intensity ΔE, which is the color difference between the non-irradiated sample and those irradiated with different gamma doses, increased (0–5.56) with increasing the dose up to 250?kGy, convoyed by an increase in the red and yellow color components.     

Modification induced by gamma irradiation in Bayfol CR 1-4 polycarbonate

Bayfol CR 1-4 polycarbonate is a class of polymeric solid state nuclear track detector which has many applications in various radiation detection fields. Samples from sheets of Bayfol have been irradiated with gamma doses ranging from 100 to 620 kGy. The structural modifications in the gamma-irradiated Bayfol samples have been studied as a function of dose, using different characterization techniques such as X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, intrinsic viscosity and refractive index. The results indicate that the carbonyl group (C?O) degraded under irradiation up to 200 kGy. This degradation, reported by FTIR spectroscopy enhanced the degree of ordering in the degraded samples as revealed by the XRD technique. Above 200 and up to 620 kGy, cross-linking is achieved, leading to an increase in the intrinsic viscosity from 0.41 to 0.78 at 35°C, indicating an increase in the average molecular mass. On the other hand, the resultant effect of gamma irradiation on the thermal properties of Bayfol has been investigated using thermo-gravimetric analysis, results indicating that the gamma irradiation in the dose range 200–620 kGy led to a more compact structure of Bayfol polymer, which resulted in an improvement in its thermal stability with an increase in the activation energy of thermal decomposition due to cross-linking. In addition, the V–I characteristics of the polymer samples were performed, results indicated that at higher voltage, the conduction mechanism of Bayfol CR 1-4 was identified as the Poole–Frenkel type.     

Effect of gamma irradiation on the structural,thermal and optical properties of Makrofol BL 2–4

Makrofol BL 2–4 is an extrusion film based on Makrolon polycarbonate. It comprises excellent die-cutting performance combined with high light transmission and moderate light scattering properties. It is a class of polymeric solid state nuclear track detectors which has many applications in various radiation detection fields. In the present work, Makrofol samples were irradiated using different gamma doses ranging from 10 to 350 kGy. The structural modifications in the gamma-irradiated Makrofol samples have been studied as a function of dose using different characterization techniques such as X-ray diffraction, intrinsic viscosity, Fourier transform infrared spectroscopy, thermogravimetric analysis, refractive index and color difference studies. The gamma irradiation in the dose range 20–200 kGy led to a more compact structure of Makrofol polymer, which resulted in an improvement in its thermal stability with an enhancement in its structural and optical properties.     

Optical and electrical properties of swift heavy ion beam-irradiated polycarbonate/polystyrene bilayer films

Polycarbonate/polystyrene bilayer films prepared by solvent-casting method were irradiated with 55 MeV carbon ion beam at different fluences ranging from 1×10¹¹ to 1×10¹³ ions cm^?2. The structural, optical, surface morphology and dielectric properties of these films were investigated by X-ray diffraction (XRD), UV–visible spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, optical microscopy and dielectric measurements. The XRD pattern shows that the percentage of crystallinity decreases while inter-chain separations increase with ion fluence. UV–visible spectroscopy shows that the energy band gap decreases and the number of carbon atoms in nanoclusters increase with the increase in ion fluences. The refractive index is also found to decrease with the increase in the ion fluence. Optical microscopy shows that after irradiation polymeric bilayer films color changes with ion fluences. The FTIR spectra evidenced a very small change in cross-linking and chain scissoring at high fluence. Dielectric constant decreases while dielectric loss and AC conductivity increase with ion fluences.     

Structural and optical studies of electron beam-irradiated Makrofol nuclear track detector

The effect of electron beam irradiation on the structural and optical properties of Makrofol solid state nuclear track detector (SSNTD) was investigated. Samples from Makrofol detector were irradiated with electron beam with doses at levels between 10 and 400 kGy. Structural and optical property studies using X-ray diffraction, FTIR spectroscopy, color difference measurements and electron paramagnetic resonance were performed on non-irradiated and irradiated Makrofol samples. The transmission of these samples in the wavelength range 200–2500 nm, as well as any color changes, was studied. A characteristic absorption bands with different intensities was observed. Using the transmission data, both the tristimulus and the Commission Internationale de l’Eclairage (CIE) LAB coordinate values were calculated. In addition, the color differences between the non-irradiated sample and those irradiated with different doses were calculated. The results indicate that the Makrofol detector is a material that does not have a high resistance to degradation, and its tendency to crosslinking is much lower than that of several other SSNTDs.     

Surface and Bulk Structure Characterization of Proton (3 MeV) Irradiated Polycarbonate

Polycarbonate (Makrofol‐N) thin films were irradiated with protons (3 MeV) under vacuum at room temperature with the fluence ranging from 1×10¹⁴ to 1×10¹⁵ protons cm^?2. The change in surface morphology, optical properties, degradation of the functional groups, and crystallinity of the proton‐irradiated polymers were investigated with atomic force microscopy (AFM), UV‐VIS, and Fourier‐transform infrared (FTIR) spectroscopy, and X‐ray diffraction (XRD) techniques, respectively. AFM shows that the root mean square (RMS) roughness of the irradiated polycarbonate surface increases with the increment of ion fluence. The UV‐VIS analysis revealed that in Makrofol‐N the optical band gap decreased by 30% at highest fluence of 1×10¹⁵ protons cm^?2. The band gap can be correlated to the number of carbon atoms, M, in a cluster with a modified Robertson's equation. The cluster size in the proton‐irradiated Makrofol‐N increased from 112 to 129 atoms with the increase of fluence from 1×10¹⁴ to 1×10¹⁵ protons cm^?2. FTIR spectra of proton (3 MeV) irradiated Makrofol‐N showed a strong decrease of almost all absorption bands at about 1× 10¹⁴ protons cm^?2. However, beyond a higher critical dose an increase in intensity of almost all characteristic bands was noticed. The appearance of a new peak at 3,500 cm^?1 (‐OH groups) was observed at the higher fluences in the FTIR spectra of proton‐irradiated polycarbonate. XRD measurements showed an increase of full width at half maximum (FWHM) and the average intermolecular spacing of the main peak, which may be due to the increase of chain scission and the introduction of ‐OH groups in the proton irradiated polycarbonate.     

Thermal,electrical and optical properties of proton-irradiated Makrofol DE 7-2 nuclear track detector

Samples from sheets of the polymeric material Makrofol DE 7-2 have been exposed to 1 MeV protons of fluences in the range 2.5×10¹³–5×10¹⁵ p/cm². The resultant effect of proton irradiation on the thermal properties of Makrofol has been investigated using thermogravimetric analysis and differential thermal analysis (DTA). The onset temperature of decomposition T _o and the activation energy of thermal decomposition E _a were calculated, and the results indicated that the Makrofol detector decomposes in one weight loss stage. Also, the proton irradiation in the fluence range 7.5×10¹³–5×10¹⁵ p/cm² led to a more compact structure of Makrofol polymer, which resulted in an improvement in its thermal stability with an increase in the activation energy of thermal decomposition. The variation of transition temperatures with proton fluence has been determined using DTA. The Makrofol thermograms were characterized by the appearance of an endothermic peak due to the melting of the crystalline phase. The melting temperature of the polymer, T _m, was investigated to probe the crystalline domains of the polymer. At a fluence range of 7.5×10¹³–5×10¹⁵ p/cm², the defect generated destroys the crystalline structure, thus reducing the melting temperature. In addition, the V–I characteristics of the polymer samples were investigated. The electrical conductivity was decreased with the increasing proton fluence up to 5×10¹⁵ p/cm². Further, the refractive index, transmission of the samples and any color changes were studied. The color intensity Δ E was greatly increased with the increasing proton fluence and was accompanied by a significant increase in the red and yellow color components.     

Short-time reactor neutron irradiation of YSZ prepared using reactive calcination method

The present work is devoted to study the short-time reactor neutron irradiation of yttria stabilised zirconia (YSZ) at 315 K. The samples were prepared by the reactive calcination method and characterised by X-ray diffraction (XRD) analysis and scanning electronic microscope. The prepared samples were irradiated by reactor neutrons at different exposure times and investigated by XRD analysis. The results obtained show good radiation resistance of YSZ to reactor neutron irradiation.     

Molecular and optical modifications in poly(vinyl chloride) due to N-phenylmaleimide additives and gamma irradiation

The effects of N-phenylmaleimide (NPMI) concentration and gamma dose on the molecular and optical properties of poly(vinyl chloride) (PVC) have been studied. The results reveal an improvement in the intrinsic viscosity of PVC in the presence of an organic material. The effective concentration that enhanced the intrinsic viscosity, from 1.02 to 1.28, was found to be 10 mmol NPMI per 100 g PVC. The effect of gamma irradiation on the PVC polymer stabilized with this concentration of NPMI has been studied. Samples from the 0.01 g NPMI/1 g PVC were irradiated with gamma doses in the range 5–180 kGy. It is found that irradiation in the dose range 120–180 kGy enhances the intrinsic viscosity of the samples. In addition, the transmission of these irradiated samples in the wavelength range 200–2500 nm, as well as any color changes was studied. The color intensity (Δ E) was greatly increased with the increasing gamma dose, and was accompanied by darkness with a significant increase in the yellow color component.     

X-ray irradiation-induced structural modifications in PM-355 polymeric nuclear track detector film

Samples from sheets of the polymeric material PM-355 have been exposed to X-rays from a 50 kV X-ray tube in the dose range of 10–300 kGy. The resultant effect of X-ray irradiation on the structural properties of PM-355 has been investigated using different techniques such as X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Vickers hardness and refractive index measurements. The results indicate that the X-ray irradiation of PM-355 in the dose range of 10–20 kGy causes initially chain scission. Above 20 and up to 100 kGy, the active free radicals produced from scission contribute to chemical reactions that lead to the crosslinking. Thus, the X-ray irradiation in the dose range of 20–100 kGy leads to a more compact structure of the PM-355 polymer, resulting in an enhancement of its Vickers hardness and refractive index. Moreover, the irradiation in the dose range of 100–300 kGy leads to the predominance of the degradation. This degradation is reported by FTIR spectroscopy and enhances the degree of ordering in the degraded samples as revealed by XRD technique. Additionally, it decreases both the Vickers hardness and refractive index of the PM-355 samples.     

Modifications induced in the polycarbonate Makrofol KG polymer by Li (50 MeV) ion irradiation

Swift heavy ions interact predominantly through inelastic scattering while traversing any polymer medium and produce excited/ionized atoms. Here samples of the polycarbonate Makrofol of approximate thickness 20 μm, spin coated on GaAs substrate were irradiated with 50 MeV Li ion (+3 charge state). Build-in modifications due to irradiation were studied using FTIR and XRD characterizations. Considerable changes have been observed in the polymer while varying the fluence from 1E11 ion/cm² to 1E13 ion/cm² Li ions. AFM images of the surface modifications caused by ion irradiation on the polymer are also presented.      

Proton-induced changes in Bayfol CR 1-4 nuclear track detector

Samples from the polymeric material Bayfol CR 1-4 have been exposed to 1 MeV protons with fluencies in the range 10¹¹–10¹⁴ ions/cm ². The resultant effect of proton irradiation on the thermal properties of Bayfol CR 1-4 has been investigated using thermo-gravimetric analysis (TGA). The onset temperature of decomposition T ₀ and activation energy of thermal decomposition E _a were calculated, results indicated that the Bayfol detector decomposes in one weight loss stage. In addition, the structural modifications in the proton-irradiated Bayfol samples have been studied as a function of fluence using X-ray diffraction and intrinsic viscosity of the liquid samples. Furthermore, the refractive index was measured for the non-irradiated and irradiated Bayfol samples. The results indicated that the degradation is the dominant mechanism in the fluence range 1×10¹¹–5×10¹⁴ ions/cm ². These results have been compared with those obtained in our previous work for Bayfol CR 6-2.     

Radiation damage in triglycine sulphate due to fast neutron irradiation

Abstract

The change in electrical properties of TGS crystals due to induced defects created by fast neutron irradiation of two different energies (2 and 14 MeV) and different integrated neutron fluxes have been studied in the vicinity of phase transition. It is observed that the electrical conductivity increases with increase of neutron fluence up to 1.7 × 10¹⁰ n · cm^?2 and the values of the relative change of electrical conductivity in case of 2 MeV are higher than that of 14 MeV neutrons at the same neutron fluence (φ)     

Carbon (70 MeV) and copper (120 MeV) ions irradiation effects in Makrofol-N

Makrofol-N polycarbonate was irradiated with carbon (70 MeV) and copper (120 MeV) ions to analyze the induced effects with respect to optical and structural properties. In the present investigation, the fluence for carbon and copper beams was kept in the range of 1×10¹¹– 1×10¹³ ions/cm² to study the swift heavy ion induced modifications. UV–VIS, FTIR and XRD techniques were utilized to study the induced changes. The analysis of UV–VIS absorption studies revealed that the optical energy gap was reduced by 17% on carbon irradiation, whereas the copper beam leads to a decrease of 52% at the highest fluence of 1×10¹³ ions/cm². The band gap can be correlated to the number of carbon atoms, N, in a cluster with a modified Robertson's equation. In copper (120 MeV) ions irradiated polycarbonate, the number of carbon atoms in a cluster was increased from 63 to 269 with the increase of ion fluence from 0 to 1×10¹³ ions/cm², whereas N is raised only up to 91 when the same polymer films were irradiated with carbon (70 MeV) ions under similar conditions. FTIR analysis showed a decrease in almost all characteristic absorption bands under irradiation. The formation of hydroxyl (? OH) and alkene (C?C) groups were observed in Makrofol-N at higher fluence on irradiation with both types of ions, while the formation alkyne end (R? C≡ CH) group was observed only after copper ions irradiation. The radii of the alkyne production of about 3.3 nm were deduced for copper (120 MeV) ions. XRD measurements show a decrease in intensity of the main peak and an increase of the average intermolecular spacing with the increase of ion fluence, which may be attributed to the structural degradation of Makrofol-N on swift ion irradiation.     

Opto-chemical response of Makrofol-KG to swift heavy ion irradiation

In the present study, the effects of swift heavy ion beam irradiation on the structural, chemical and optical properties of Makrofol solid-state nuclear track detector (SSNTD) were investigated. Makrofol-KG films of 40 μm thickness were irradiated with oxygen beam (O^8 +) with fluences ranging between 10¹⁰ ion/cm² and 10¹² ion/cm². Structural, chemical and optical properties were investigated using X-ray diffraction, FTIR spectroscopy and UV–visible spectroscopy methods. It is observed that the direct and indirect band gaps of Makrofol-KG decrease after the irradiation. The XRD study shows that the crystalline size in the films decreases at higher fluences. The intensity plots of FTIR measurements indicate the degradation of Makrofol at higher fluences. Roughness of the surface increases at higher fluence.     

Study of structural,morphological and mechanical properties of PMMA,PVC and their blends

PMMA, PVC and their five blends in different compositions were irradiated by γ -rays of 2 Mrad dose. A comparative study of structural, morphological and mechanical properties of irradiated and non-irradiated samples was carried out. The structural changes that have taken place due to irradiation are seen in the FTIR and X-ray diffraction (XRD) spectra. The ester group is mainly affected in PMMA and the blends. The XRD results have confirmed that the irradiated samples are more amorphous in nature than the non-irradiated ones. The DSC study reveals that some irradiated samples undergo cross-linking, whereas some of them undergo degradation. One of the irradiated blend compositions has become thermally more stable. The SEM study suggests that the irradiated samples have undergone curing. An improvement in the mechanical properties has been observed in some of the irradiated blend compositions.     

The behavior of HfB2 at neutron irradiation: a simulation study

The behavior of Hafnium di-boride (HfB₂) under neutron irradiation has been simulated in a wide range of energy from 0.025?eV up to 14?MeV. The simulation and the analysis have been carried out using Geant4 and its related database. From the radiation shielding perspective, it was observed that, under thermal neutron irradiation, HfB₂ scatters neutrons with a marginally higher energy than the incident neutrons and also produces prompt gamma rays up to 11?MeV. These results would indicate that, for high-energy neutron 14?MeV, not only is HfB₂ unacceptable as a reasonable neutron absorber but also produces 20?MeV prompt gamma rays.     

Modification of polyethylene terephthalate by proton irradiation

Polyethylene terephthalate (PET) films were irradiated with 3 MeV proton beams at different fluences. The microhardness, electrical, thermal and structural studies were carried out using microhardness tester, LCR meter, thermogravimetric analysis (TGA) and FTIR spectroscopy. Vickers' hardness has been observed to increase with the fluence. The true bulk hardness of the film was obtained at loads greater than 400 mN. The AC electrical conductivity is practically unaffected by irradiation up to a frequency of 10 kHz, but it is found to increase exponentially at a frequency of 300 kHz. The loss factor and dielectric constant are observed to change appreciably with the fluence. It is observed that there is no significant change in the stability of the polymer up to the fluence of 10¹⁴ ions cm^?2 as revealed by TGA and FTIR spectroscopy.