Structural, optical, thermo-mechanical and transport properties of ion irradiated polymer membranes

Summary The modifications in PET induced by swift heavy ion irradiation are analyzed. PET membrane of 15 μm was irradiated by Cl⁹⁺ ions of 100 MeV at TIFR Mumbai. The changes due to exposure to high-energy ions were investigated by Fourier Transform Infrared (FTIR) and Ultraviolet/ Visible absorption (UV/VIS) spectroscopies, X-Ray diffraction technique, dynamic mechanical analysis and by the gas permeation. A significant loss of crystallinity is observed by the XRD data. Particle size or grain size calculated using Scherrer formula indicates measurable change in particle size of irradiated samples. The polymer chain scissions and structure degradations are expected to occur for irradiated samples. Optical properties of the films were changed due to irradiation that could be clearly seen in the absorption and FTIR spectra. Gas permeation through these membranes before and after irradiation using hydrogen and carbon dioxide gases shows that permeability for both gases increased after irradiation but permeability for hydrogen is higher than carbon dioxide due to its small molecular size.     

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.     

Effect of cobalt-60 γ radiation on the physical and chemical properties of poly(ethylene terephthalate) polymer

The structural, optical, and morphological properties of Co⁶⁰ γ irradiation on poly(ethylene terephthalate) polymer samples were studied with X-ray diffraction (XRD), ultraviolet–visible spectroscopy, scanning electron microscopy (SEM), and Raman spectroscopy. The diffraction pattern of virgin sample showed that the polymer was semicrystalline in nature. However, because of irradiation, the crystallinity decreased up to a dose level of 110 kGy and increased up to 300 kGy. The crystallite size, strain, and dislocation were calculated from the XRD data, and the crystallite size decreased from 291.07 to 346.90 Å. The absorption edge shifted from 315 to 330 nm, and the band gap of the samples decreased from 3.79 to 3.66 eV. The SEM micrographs showed radial bulging along with inhomogeneous liner exfoliation, and also, a rocky shape pattern with different sizes was observed. A significant change was found in the Raman spectra of the γ-irradiated polymer at the highest dose. The results of the structural, optical, and morphological studies show recovery characteristics at the highest dose level of 300 kGy. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

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.     

Crosslinking of poly(vinyl acetate) nanolatices by gamma and UV radiation

Poly(vinyl acetate) PVAc, in nanolatices with 10% polymer content, prepared by microemulsion polymerization was crosslinked by gamma and UV radiation. PVAc colloidal nanoparticles (average diameter, Dp = 58 nm) had M_w = 562,000 g/mol and about 95% conversions. PVAc nanolatices irradiated by gamma rays (1–13 kGy) at room temperature without crosslinking agent and by UV light (30–300 s exposure times) in the presence of divinylbenzene and allyl methacrylate showed crosslinking of up to 96% (high gel content), Dp < 100 nm and did not degrade as shown by FTIR spectroscopy. DSC and TGA characterization of irradiated PVAc samples indicated that T_g temperatures increased from 28°C for PVAc to 42°C and 39°C for UV and gamma rays crosslinked PVAc, respectively, whereas 10% weight losses occurred at 261°C for uncrosslinked PVAc and at 320 and 313°C for UV and gamma rays crosslinked PVAc. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effect of gamma irradiation on optical and chemical properties of cellulose nitrate thin films

In this work, cellulose nitrate films were irradiated with different doses of gamma irradiations. The gamma irradiation doses were 25, 55, 120, and 170 kGy. The compositional transformation, optical properties, and morphological changes resulted from the gamma irradiation were obtained using different spectroscopic methods. These methods were Fourier transform infrared spectrometry, UV/visible spectrometry, and scanning electron microscope. The surface roughness, as well, for pristine and gamma-irradiated polymer films was determined. The obtained results exhibit changes in the absorbance intensities of the function groups of the irradiated cellulose nitrate films. An induced increase in the UV/visible absorption spectra with increase in the gamma irradiation was observed. A noticeable shifting in the UV/visible spectra toward higher wavelength and decrease in the optical band gap were observed as the gamma irradiation increases. As well, the number of carbon clusters and the activation energy were discussed. The morphological investigation indicates the decrease in the roughness surface with increasing of gamma irradiation.     

In situ preparation of CdS/PVA nanocomposites using gamma radiation

Films of poly(vinyl alcohol)/cadmium sulphide (PVA/CdS) nanocomposite containing various concentrations of Cd²⁺ ions were prepared using gamma radiation at different doses from 50 up to 200 kGy. The UV/VIS spectra revealed that the CdS/PVA nanocomposites showed blue shift for the absorption peak as compared with bulk CdS. As the irradiation dose increased, a gradual red shift in the wavelength accompanying with broadening of the absorption peak was observed. The estimated optical band gap energies and the calculated CdS particle sizes of (PVA/CdS) showed correlation between their values and the variable parameters (irradiation dose and Cd⁺²:S^?2 molar ratio). Transmission electron microscopy images showed that the CdS/PVA nanocomposites were dispersed as spherical CdS nanoparticles with homogeneity at either lower concentration of CdCl₂ or irradiation dose. The nano‐rod structures of CdS was accompanied with small agglomeration at either higher CdCl₂ concentration or irradiation dose. A cubic phase and mixture of cubic and hexagonal phases of the prepared CdS nanoparticles were formed at lower and higher CdCl₂ concentrations, respectively. Fourier Transform Infrared spectra confirmed the coordination of CdS nanoparticles with the hydroxyl groups of PVA matrix. POLYM. ENG. SCI., 55:2583–2590, 2015. © 2015 Society of Plastics Engineers     

Radiation Resistance and Mechanical Stability of SiO2–BaO-Based Glass Coatings for Space Solar-Cell Panels

The influence of proton irradiation (energy, 18 MeV; beam current, 300 nA) with doses of 5 × 10¹⁴, 10¹⁵, and 5 × 10¹⁵ cm^–2 on samples of SiO₂–BaO-based glass coatings is investigated. The absorption, photoluminescence, and gamma luminescence spectra of the studied samples and their microhardness are measured. It is found that proton irradiation leads to a twofold increase in the microhardness. An insignificant increase in the optical absorption is revealed in the near-ultraviolet range (200–400 nm). This increase is accompanied by a decrease in the intensity of both light scattering in the wavelength range 400–900 nm and photoluminescence. The intensity of broadband gamma luminescence with a maximum at a wavelength of 500 nm increases with increasing proton irradiation dose. This means that excitonic radiative recombination impedes the formation of structural defects and their associated color centers. The combined effect of proton irradiation and solar electromagnetic radiation (gamma and visible light rays) accompanied by temperature changes in the range 80–470 K can provide an increase in the radiation resistance and mechanical stability of glass coatings used for solar-cell panels and their longer service life even under conditions of increased solar activity.     

Structural and morphological study of gamma‐irradiation synthesized silver nanoparticles

Silver nanostructured particles with controlled size, shape, and morphology were achieved by gamma irradiation of aqueous solution containing AgNO_3, ploy (vinyl pyrrolidone), (PVP) or mixture of PVP and ploy (vinyl alcohol), (PVA). The reaction condition parameters such as solvent content, polymer type and irradiation dose were investigated. The physico‐chemical properties and morphological structures of the as‐prepared sliver nanostructures were characterized using UV/VIS spectroscopy, TEM, XRD, and Fourier transform infrared spectroscopy (FTIR) spectroscopy. Hexagonal and nanorods structures of sliver nanoparticles having single surface plasmon resonance peak and triangular (nanoprism) nanoparticles having different surface plasmon resonance peak were obtained. The XRD patterns of the as‐prepared silver nanostructure show four diffraction peaks at 2θ of 38.4°, 44.5°, 64.6°, and 77.6° of the face‐centered cubic structure silver nanoparticles. FTIR measurements indicated that the sliver nanoparticles were coordinated through the functional groups of PVA and/or PVP. POLYM. COMPOS., 38:2687–2694, 2017. © 2015 Society of Plastics Engineers     

Thermoplastic elastomer based on waste polyethylene/waste rubber containing activated carbon black: Impact of gamma irradiation

The effect of using gamma radiation on the prepared activated carbon (AC) from carbon black using dose 500 kGy was studied. Moreover, AC powder were blended in internal mixer to prepare thermoplastic elastomer with percentage (75/25/10) wt% based on waste polyethylene and waste rubber which irradiated before mixing at dose100 kGy separately and AC. Chemical activity of composites was improved as a result of using gamma radiation which was examined by electron spin resonance estimations. Composites were studied by different techniques, such as FTIR, mechanical, thermal, morphology, and X‐ray diffraction. The results indicated that optimistic effect of using gamma rays with improving the properties of the composites. J. VINYL ADDIT. TECHNOL., 25:E166–E176, 2019. © 2018 Society of Plastics Engineers     

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.     

Radiation‐induced polymerization of butyl acrylate for recovery of organic solvents

Radiation‐induced polymerization of butyl acrylate using ⁶⁰Co gamma rays has been investigated under different conditions, such as irradiation dose (0–130 kGy), dose rate (10 kGy/h), and temperature (25–70°C). A linear relationship between conversion and temperature of irradiation was found. The activation energy (E) of 9.37 kJ/mol was obtained from kinetic analysis of the result from the polymerization at 10 kGy/h. Thermal properties were examined using differential scanning calorimetry and thermal gravimetric analysis. Efficient extraction of organic solvents including chloroform, chlorobenzene, carbon tetrachloride, benzene, styrene was revealed by the swelling and releasing measurements. These results indicate the feasibility of applying this polymer, which was prepared by radiation‐induced polymerization, to management of organic wastes in the field of environment. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effects of gamma radiation on properties of halogen‐free flame retardant EPDM‐PVMQ rubber blends

In this study, the effects of gamma radiation on properties of ethylene–propylene–diene monomer (EPDM) and its blends with phenyl vinyl methyl silicon rubber (PVMQ) were studied. The samples were irradiated with the dose rate of 171.7 Gy/min, and the total dose was up to 500 kGy. Mechanical properties, electrical insulation, limiting oxygen index (LOI), crosslink density, and ATR‐FTIR spectroscopy of the rubber were carried out to characterize the properties via irradiation. The results indicated that PVMQ acted as an irradiation degradation retarder for EPDM. After a postvulcanized period corresponding to 50 kGy dose, the elongation at break and electrical insulation decreased with LOI unaffected, while the crosslink density and tensile strength presented a complicated change with the increasing of radiation dose. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Study of a Polydimethylsiloxane (PDMS) Elastomer Generated by γ Irradiation: Correlation Between Properties (Thermal and Mechanical) and Structure (Crosslink Density Value)

The present study investigates the structural modification of polydimethylsiloxane (PDMS) with a molecular weight of 35 kDa, using varying high doses of gamma irradiation. Elastomeric structures with different crosslinked density values were obtained as a function of the gamma irradiation dose (250, 300, 350 and 400 kGy). The structural characterization of the obtained elastomers was performed by employing Fourier Transform Infrared, ²⁹Si Magic Angle Spinning Nuclear Magnetic Resonance and X-Ray Diffraction (FTIR, ²⁹Si MAS NMR and XRD), showing integration with the polymer chains by siloxane crosslinks (Type-Y) and methylene crosslinks (Type-H). The mechanical and thermal characterizations were carried out by employing dynamical-mechanical analysis (DMA) and modulated differential scanning calorimetry (MDSC). The results showed an important correlation between the thermo-mechanical behavior and the irradiation dose. The thermal stability, analyzed by a thermo-gravimetric analysis (TGA), exhibited interesting behavior that suggested a direct correlation between the decomposition temperature and the structure generated by the gamma irradiation. These results suggest that the obtained elastomers could potentially be considered shape changing materials (SCM).     

Room Temperature Radiolytic Synthesized Cu@CuAlO2-Al2O3 Nanoparticles

Colloidal Cu@CuAlO₂-Al₂O₃ bimetallic nanoparticles were prepared by a gamma irradiation method in an aqueous system in the presence of polyvinyl pyrrolidone (PVP) and isopropanol respectively as a colloidal stabilizer and scavenger of hydrogen and hydroxyl radicals. The gamma irradiation was carried out in a ⁶⁰Co gamma source chamber with different doses up to 120 kGy. The formation of Cu@CuAlO₂-Al₂O₃ nanoparticles was observed initially by the change in color of the colloidal samples from colorless to brown. Fourier transform infrared spectroscopy (FTIR) confirmed the presence of bonds between polymer chains and the metal surface at all radiation doses. Results of transmission electron microscopy (TEM), energy dispersive X-ray spectrometry (EDX), and X-ray diffraction (XRD) showed that Cu@CuAlO₂-Al₂O₃ nanoparticles are in a core-shell structure. By controlling the absorbed dose and precursor concentration, nanoclusters with different particle sizes were obtained. The average particle diameter increased with increased precursor concentration and decreased with increased dose. This is due to the competition between nucleation, growth, and aggregation processes in the formation of nanoclusters during irradiation.     

The effect of UV‐irradiation and molten medium on the mechanical and thermal properties of polystyrene–polycarbonate blends

Polymer materials with improved properties can be obtained through polymer blends. As a polymer mixture is generally immiscible and incompatible, it is necessary to develop new methods to improve the interfacial adhesion. The aim of this work is to find formulations and associated processes to upgrade engineering polystyrene (PS) and polycarbonate (PC) polymer blends with the objective of using the best “process‐formulation” couple. In this study, blends of PS/PC were prepared in molten medium using reactive extrusion after UV‐irradiation. The effects of UV‐irradiation on some properties of blends under molten medium were investigated by differential scanning calorimetry (DSC), fourier transform infrared (FTIR), and thermogravimetric analysis (TGA). The data showed that the presence of polycarbonate in the blend increased the tensile strength and elongation at break with respect to pure PS. The mechanical properties of the blends were improved after irradiation. All irradiated blends are thermally more stable than those nonirradiated. Chemical changes can be clearly seen in FTIR spectra through two bands assigned to C?O and OH groups. The mutual influence between the PS/PC polymer blends compositions during UV‐irradiation was studied. PS and PC have different photo‐mechanisms due to the larger UV absorption of polystyrene and formation of more stable tertiary carbon radicals. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Changes in structural characteristics of LLDPE functionalized with DEM using gamma‐irradiation

This work studies the structural changes produced by gamma‐radiation as a source of free radicals for functionalizing linear low‐density polyethylene (LLDPE) with diethyl maleate (DEM). The grafting of the DEM onto the LLDPE was carried out in solution using gamma‐rays from a ⁶⁰Co source in air at room temperature, at a dose rate of 4.8 kGy/h and absorbed doses ranging from 15 to 400 kGy. The increase in the dose produced a higher concentration of free radicals and hence a higher grafting degree. The effects of DEM concentration are only perceptible at absorbed doses higher than 50 kGy. For a concentration of 30% DEM, the functionalization degrees ranged from 0.04 to 0.44 mol%. The use of gamma radiation modifies the structural and physical characteristics of the functionalized polyethylene with respect to the unmodified one, because, depending on the dose, the effects of gamma‐rays can lead to crosslinking of materials with decreased flowability. The effects of gamma‐radiation onto the molecular structure and molecular weight distribution of LLDPE are mitigated by the presence of DEM, due to the competition with the chain scission, branching and crosslinking reactions, for the consumption of the free radicals. The results provided by applying the successive self‐nucleation and annealing technique allow reaching an unequivocal conclusion: that the free radicals formed by gamma radiation for the DEM insertion and main chain modifications are preferentially generated in the secondary carbons of the more regular ? CH₂? sequences. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Thermal and physicomechanical properties of gamma‐irradiated EPDM/waste newsprint microfibers composites treated using acrylic styrene emulsion as a coupling agent

This investigation deals mainly with thermal stability and crosslinking density of EPDM/newsprint microfibers composites. The recycled newsprint microfibers were treated using a different ratio of acrylic styrene emulsion (5, 10, and 15 wt% fiber) as a bonding agent to reinforce EPDM rubber matrix. The effect of microfibers content, namely, 5 up to 50 phr (part per hundred part of rubber) and the effect of ionizing radiation on EPDM/newsprint microfibers composites properties were investigated. The microfibers structure and EPDM/microfibers composite were investigated using X‐ray diffraction and FTIR analysis; the results indicate that bonding has occurred between the treated newsprint microfibers and EPDM polymer matrix. EPDM/untreated newsprint microfibers composites have achieved higher crosslinking density than EPDM matrix up to 50 phr microfibers content and up to 100 kGy then decreased with increasing gamma irradiation dose. Meanwhile treatment of the microfibers using 10 wt% acrylic styrene leads to improve crosslinking density at any microfibers content. Thermogravimetric analysis (TGA) was carried out for the microfibers and their composites. TGA indicated that the thermal stability of microfiber was enhanced using acrylic styrene. Whereas there is a slight improvement in thermal stability and activation energy of the composites due to adding treated microfibers using 10 phr microfiber content treated using10 wt% acrylic styrene emulsion and irradiated with 60 kGy gamma radiation dose. J. VINYL ADDIT. TECHNOL., 25:E91–E106, 2019. © 2018 Society of Plastics Engineers     

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.

     

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