Effect of fast neutron irradiation on the structural and optical properties of Makrofol DE 1-1 CC polycarbonate

Samples from sheets of the polymeric material Makrofol DE 1-1 CC have been exposed to neutrons of incident energy in the range of 0.8–19.2 MeV. The modifications induced in Makrofol samples due to neutron 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. Infrared spectroscopy indicated that cross-linking is the dominant mechanism in the energy range of 2.3–19.2 MeV. The cross-linking reported by FTIR spectroscopy destroyed the degree of ordering in the Makrofol samples, as revealed by the XRD technique. Also, this cross-linking led to an increase in the values of intrinsic viscosity from 0.41 to 0.68 at 28 °C, indicating an increase in the average molecular mass, associated with an increase in the refractive index. Additionally, the non-irradiated Makrofol samples showed significant color sensitivity toward neutron irradiation. The sensitivity toward neutron irradiation can be seen by the change in the blue color component of the non-irradiated Makrofol film to yellow after the samples are exposed to neutrons up to 19.2 MeV. This is accompanied by a net increase in the darkness of the samples.     

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.     

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.     

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.     

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.     

Structural modifications induced in Bayfol polycarbonate due to heavy highly energetic ions irradiations

The effects of 28 GeV ⁵⁶Fe and 13.72 GeV ²⁸Si ion irradiation on the structural properties of two types of Bayfol, namely DPF 5023 and CR 1–4 polycarbonates, have been investigated. It is worth mentioning that this report is almost the first one dealing with the topic of material changes in such a high energy range. Samples from each type of Bayfol were classified into two groups. The first group has been exposed to Fe ion fluences at levels between 2000 and 8000 ion/cm². The second group has been exposed to Si ions with similar fluences. The total energy deposited is between 27.44 and 224 E12 eV. The modifications induced in Bayfol samples due to ion irradiation have been studied using X-ray diffraction (XRD) and Fourier Transform Infrared spectroscopy. The results indicate that the Fe ion irradiation causes crosslinking in Bayfol DPF 5023, reflected as a decrease in the ordering character. Also, the tendency of Bayfol CR 1–4 to crosslinking due to Fe ion irradiation is lower than that of Bayfol DPF 5023. On the other hand, the Si ion irradiation causes mainly chain scission at the carbonate site of both types of Bayfol associated with the formation of hydroxyl group.     

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.     

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.     

Effect of IR laser radiation on the structure and optical properties of PC-PBT/Pd polymer nanocomposite films

ABSTRACT

Bayfol (PC-PBT blend ?lm) is a class of polymeric solid-state nuclear track detector which has a lot of applications in several radiation detection ?elds. It is a bisphenol-A polycarbonate PC blended with polybutylene terephthalate PBT. Bayfol/Palladium (PC-PBT/Pd) nanocomposite films have been deposited using the molding technique. It is worth mentioning that this report is almost the first one dealing with the topic of the changes of physical properties of Bayfol/Pd nanocomposite due to laser exposure. Samples from PC-PBT/Pd (5?wt%) nanocomposite were exposed to IR-pulsed laser of 5-W power, capable of producing 2000 pulses per second with pulse duration of 200?ns at 904?nm. The laser fluences were in the range 2–25?J/cm². The resultant modi?cations in the exposed nanocomposite samples have been studied as a function of fluence using different characterization techniques such as X-ray diffraction (XRD), UV spectroscopy and color difference studies. The results indicate the proper dispersion of Pd nanoparticles in the PC-PBT matrix that causes a strong intermolecular interaction between Pd and PC-PBT, resulted in an increase in refractive index and the amorphous phase. Also, it is found that the laser exposure reduces the optical energy gap that could be attributed to the increase in structural disorder of the exposed PC-PBT/Pd nanocomposites due to crosslinking. Further, the color intensity ΔE, which is the color difference between the exposed samples and the non-exposed one, was increased with increasing the laser fluence, convoyed by a significant increase in the green and yellow color components.     

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.     

Effect of electron beam irradiation on the structural,thermal and optical properties of poly(vinyl alcohol) thin film

Poly(vinyl alcohol) (PVA) polymer was prepared using the casting technique. The obtained PVA thin films have been irradiated with electron beam doses ranging from 20 to 300 kGy. The resultant effect of electron beam irradiation on the structural properties of PVA has been investigated using X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR), while the thermal properties have been investigated using thermo-gravimetric analysis and differential thermal analysis (DTA). The onset temperature of decomposition T ₀ and activation energy of thermal decomposition E _a were calculated, results indicate that the PVA thin film decomposes in one main weight loss stage. Also, the electron beam irradiation in dose range 95–210 kGy led to a more compact structure of the PVA 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 electron beam dose has been determined using DTA. The PVA thermograms were characterized by the appearance of an endothermic peak due to melting. In addition, the transmission of the PVA samples and any color changes were studied. The color intensity Δ E was greatly increased with increasing electron beam dose, and was accompanied by a significant increase in the blue color component.     

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.     

Modifications induced by gamma irradiation upon structural,optical and chemical properties of polyamide nylon-6,6 polymer

The effects of gamma rays were studied on the optical, structural and chemical properties of the PA-66 polymer samples. The polymer samples obtained from Goodfellow (Cambridge, UK) were irradiated with gamma rays at various doses ranging from 100 to 1250 kGy. The pristine and gamma rays irradiated samples were characterized by UV–visible (UV–VIS) spectroscopy, X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. UV–VIS shows a shift in absorption toward the visible region for irradiated samples and a decrease in band gap energy (E_g). The XRD analyses show an increase in the crystalline nature of the polymer at higher doses as a result of significant decrease in the peak width of XRD patterns. The FTIR spectra show decrease in intensity and shift of various bands with increase in gamma dose.     

Changes induced in structure and optical properties of PM-355 nuclear track detector due to laser irradiation

PM-355 is a class of polymeric solid-state nuclear track detectors which has a lot of applications in several radiation detection fields. Samples from sheets of PM-355 have been exposed to infrared (IR) laser fluences ranging from 1 to 12.8?J/cm². The effect of IR laser radiation on the structural properties of PM-355 has been investigated using X-ray diffraction and Fourier transform infrared spectroscopy. The results indicate that the samples exhibit chain scission under the effect of laser irradiation up to 4.2?J/cm², thus producing free radicals that led to the formation of new bonds started and continued until 12.8?J/cm². This reduces the ordering structure, giving the PM-355 polymer more resilience. In addition, the laser irradiation at the fluence range 4.2–12.8?J/cm² led to a more compact structure of PM-355, which resulted in an improvement in its isotropic nature with an increase in Vickers hardness and refractive index. Further, the color changes due to laser irradiation were computed using the transmission data in the wavelength range of 370–780?nm. It is found that the color intensity, which is the color difference between the irradiated samples and the non-irradiated one, increases with increasing the laser fluence, largely depending on the proportions of the blue color component.     

Characterization of structural modifications in poly-tetra-fluoroethylene induced by electron beam irradiation

The effects of electron beam irradiation doses on the poly-tetra-fluoroethylene (PTFE) have been studied. Several techniques, such as X-ray diffraction (XRD), differential scanning calorimetry (DSC), mechanical properties and Fourier transform infrared spectroscopy (FTIR) were applied to characterize the PTFE samples and to study the radiation effects on the crystal structure of the polymer.The irradiation dose up to 150 kGy showed an increase in the crystallinity degree of PTFE, which has been observed and confirmed during the DSC and XRD measurements. The increase in crystallinity was attributed to the scissions of the chain in the amorphous region. Moreover, the number-average molecular weights were estimated from the heat of crystallization measured by DSC technique. The results indicated that the molecular weights were decreased by increasing the heat of crystallization due to irradiation with doses up to 150 kGy. Radiation resistance of the irradiated and non-irradiated PTFE was investigated during its mechanical properties at room temperature. The dose at half value of the elongation at break is about 3.10 kGy while the dose at half value of the tensile strength is about 1.70 kGy.     

稀土离子掺杂纳米TiO_2的太赫兹光谱研究

对sol-gel法制备的不同稀土元素(Ce,Nd,Sm)掺杂的纳米TiO2粒子进行研究。X射线衍射(XRD)和X射线光电子能谱(XPS)分析结果表明,稀土离子均以间隙的形式均匀分布在纳米TiO2晶格内。傅里叶变换红外光谱(FTIR)和太赫兹时域光谱(THz-TDS)显示,掺杂TiO2较纯TiO2具有更强的红外活性;在0.2~1.70 THz波段,TiO2的折射率随着频率的增加而减小,并呈现反常色散现象;Ce掺杂引起新的特征吸收,分别为1.35和1.58 THz,且造成太赫兹吸收谱的吸收边发生红移,Nd和Sm掺杂则造成吸收边蓝移。在0.2~1.7 THz范围内,Sm掺杂引起的介电损耗角正切值(taneδ)最小,其平均值为0.05。     

Effect of gamma irradiation on the structural and optical properties of PVA/CdS nanocomposite films prepared by ex-situ technique

ABSTRACT

For a comprehensive understanding of the PVA/CdS nanocomposite properties, it is essential to select the suitable method for their preparation as well as elucidate the interfacial interactions, which still need support. CdS nanoparticles have been prepared by thermolysis method under the flow of nitrogen. Rietveld refinement of x-ray data shows that all the CdS samples have both cubic and hexagonal structures. Then PVA/CdS films were prepared by ex-situ technique. Samples from PVA/CdS nanocomposite have been irradiated with gamma doses in the range 10–120?kGy. The implanting of CdS NPs into PVA matrix was confirmed by XRD hand in hand with UV–vis and FTIR spectroscopic techniques. UV/VIS absorption spectra confirm the formation of hybridized film CdS/PVA nanocomposite with a refractive index in the range of 1.32–1.48 (at 500?nm). UV/VIS measurements were also used in calculating different optical parameters such as refractive index, extinction coefficient and optical band gap energy. Additionally, Tauc’s relation was used to determine the type of electronic transition. It is found that the gamma irradiation in the dose range 30-90?kGy led to a more compact structure of PVA/CdS nanocomposite and causes proper dispersion of CdS nanoparticles in the PVA matrix. This led to the formation of coordination reaction between OH of PVA and CdS nanoparticles, resulted in an increase in refractive index and the amorphous phase. Also, the gamma irradiation reduces the optical energy gap from 4.53 to 2.19?eV, and accompanied with an increase in the Urbach energy from 2.28 to 4.46?eV, at that dose range which could be attributed to the increase in structural disorder of the irradiated PVA/CdS nanocomposites due to crosslinking. Further, the color intensity ΔE, which is the color difference between the non-irradiated sample and the irradiated ones, was increased, from 0 to 10.8, with increasing the gamma dose, convoyed by an increase in the red and yellow color components.     

A study of the effect of gamma and laser irradiation on the thermal,optical and structural properties of CR-39 nuclear track detector

A comparative study of the effect of gamma and laser irradiation on the thermal, optical and structural properties of the CR-39 diglycol carbonate solid state nuclear track detector has been carried out. Samples from CR-39 polymer were classified into two main groups: the first group was irradiated by gamma rays with doses at levels between 20 and 300 kGy, whereas the second group was exposed to infrared laser radiation with energy fluences at levels between 0.71 and 8.53 J/cm². Non-isothermal studies were carried out using thermogravimetry, differential thermogravimetry and differential thermal analysis to obtain activation energy of decomposition and transition temperatures for the non-irradiated and all irradiated CR-39 samples. In addition, optical and structural property studies were performed on non-irradiated and irradiated CR-39 samples using refractive index and X-ray diffraction measurements. Variation in the onset temperature of decomposition T _o, activation energy of decomposition E _a, melting temperature T _m, refractive index n and the mass fraction of the amorphous phase after gamma and laser irradiation were studied.

It was found that many changes in the thermal, optical and structural properties of the CR-39 polymer could be produced by gamma irradiation via degradation and cross-linking mechanisms. Also, the gamma dose has an advantage of increasing the correlation between thermal stability of the CR-39 polymer and bond formation created by the ionizing effect of gamma radiation. On the other hand, higher laser-energy fluences in the range 4.27–8.53 J/cm² decrease the melting temperature of the CR-39 polymer and this is most suitable for applications requiring molding of the polymer at lower temperatures.