The effect of gamma radiation on the mechanical and microstructural properties of Fe-rich inorganic polymers (original) (raw)
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When polymeric materials like Polyallyl diglycol carbonate (PADC), Polycarbonate (PC), Polyvinyl Chloride (PVC), Polypropylene (PP) etc. are exposed to gamma radiation, they show pronounced changes in their physical and chemical properties. Interestingly, the changes due to irradiation are varied in nature, proving that all polymers do not undergo similar type of modifications under similar irradiation conditions. Thus, while polymers like PADC and PVC do not reveal any change in the IR spectral pattern, the IR spectrum of polypropylene polymer confirms the total destruction of isotactic arrangements of the polymer leading to the formation of alcoholic and ketonic groups. The etch-rates are drastically enhanced due to irradiation at the highest dose for all types of PADC detectors which is not the case for polycarbonates. For polyacetate polymer, elimination of carbon dioxide takes place due to destruction of the ester group. Interestingly, in polycarbonate polymer it was observed that at the dose of 10 6 Gy, phenolic groups form due to cleavage of ester bonds. Thermal stability of PADC (American-Acrylics) is drastically reduced at the doss of 10 6 Gy, whereas for polypropylene polymer, the stability is greatly enhanced. It is also observed that due to etching, thermal stability of PADC detectors decreases. Dielectric studies reflect the fact that at a gamma dose of higher than 10 4 Gy, PADC detector may not behave as an ideal nuclear track detector. This paper accounts the modifications on different types of polymeric track detectors due to gamma irradiation. Variations in different properties such as track properties, structural modifications, thermal properties, electrical properties etc. through a dose range of 10 1 Gy to 10 6 Gy are discussed
Gamma Radiation Processed Polymeric Materials for High Performance Applications: A Review
Frontiers in Chemistry, 2022
The polymeric properties are tailored and enhanced by high energy radiation processing, which is an effective technique to tune the physical, chemical, thermal, surface, and structural properties of the various thermoplastic and elastomeric polymeric components. The gamma and electron beam radiation are the most frequent radiation techniques used for crosslinking, compatibilizing, and grafting of various polymer blends and composites systems. The gamma radiation-induced grafting and crosslinking are the effective, rapid, clean, user-friendly, and well-controlled techniques for the polymeric materials for their properties improvement for high performance applications such as nuclear, automobile, electrical insulation, ink curing, surface modification, food packaging, medical, sterilization, and health-care in a different environment. Similarly, electron beam radiations crosslinking has been a well-known technique for properties development and has economic benefits over chemical cros...
Structural Modifications of Gamma Irradiated Polymers: An FT-IR Study
A comprehensive study of structural modifications of gamma irradiated polymers in the dose range of 10 1 Gy to 10 6 Gy, was conducted using FT-IR technique. The results were varied in nature, proving that all polymers do not undergo similar type of destruction under similar irradiation conditions. The IR spectrum of polypropylene polymer confirmed the total destruction of isotactic arrangements of the polymer. The destruction of the polypropylene polymer lead to the formation of alcoholic and ketonic groups. For polyacetate polymer, elimination of carbon dioxide took place due to destruction of the ester group. Interestingly, for polycarbonate polymer also, it was observed that at the dose of 10 6 Gy, phenolic group formed due to cleavage of ester bonds. For polyvinyl chloride, there was a clear spectral indication regarding the formation of C=C bond and simultaneous decrease in concentration of C-Cl bond which took place upon gamma irradiation.
The Effect of Irradiation on Mechanical and Thermal Properties of Selected Types of Polymers
Polymers, 2018
This article deals with the influence of electron-beam radiation on the micro-mechanical, thermo-mechanical, and structural properties of selected polymers. In the search for the desired improvement of polymers, it is possible to use, inter alia, one particular possible modification-Namely, crosslinking-Which is a process during which macromolecular chains start to connect to each other and, thus, create the spatial network in the structure. In the course of the treatment of the ionizing radiation, two actions can occur: crosslinking and scission of macromolecules, or degradation. Both these processes run in parallel. Using the crosslinking technology, standard and technical polymers can acquire the more "expensive" high-tech polymeric material properties and, thus, replace these materials in many applications. The polymers that were tested were selected from across the whole spectra of thermoplastics, ranging from commodity polymers, technical polymers, as well as high-performance polymers. These polymers were irradiated by different doses of beta radiation (33, 66, 99, 132, 165, and 198 kGy). The micro-mechanical and thermo-mechanical properties of these polymers were measured. When considering the results, it is obvious that irradiation acts on each polymer differently but, always when the optimal dose was found, the mechanical properties increased by up to 36%. The changes of micro-mechanical and thermo-mechanical properties were confirmed by structural measurement when the change of the micro-hardness and modulus corresponded to the crystalline phase change as determined by X-ray and gel content.
Materials Research, 2012
B r a z i l i a n p o l y (3-h y d r o x y b u t y r a t e) , P (3-H B) , a n d i t s c o p o l y m e r, p o l y (3-hydroxybutyrate-co-3-hydroxyvalerate), P(3-HB-co-3-HV) were irradiated with gamma radiation (60 Co) at room temperature and in the presence of oxygen. The viscosity-average molar mass (Mv) was analyzed by viscometry using an Ostwald-type capillary viscometer. Both polymers showed a decrease in molar mass with the increase in dose, reflecting that random main chain scissions occurred. The value G (scissions/100 eV of energy transferred to the system) and the parameter α (scissions per original molecule) were also determined. Mechanical properties decrease with the increase in dose, revealing that P(3-HB) underwent significant changes, especially at doses higher than 50 kGy. Tensile at break and impact resistance properties were the most affected by radiation, while the elastic modulus remained virtually unaltered up to 100 kGy dose.
Compressive strength of gamma-irradiated polymer concrete
Polymer Composites, 2008
Polymer concrete (PC) was developed by using different concentrations of silica sand as aggregate and a commercial unsaturated preaccelerated (orthophtalic) polyester resin. The PC specimens were submitted to gamma radiation at several dosages: 5, 10, 50, 100, and 150 kGy. Mechanical performance was evaluated including the compressive strength, the compressive strain at yield point, and the compression modulus of elasticity. As expected, mechanical properties depend on both the resin concentration and the applied radiation dose. Improvement achieved in mechanical properties is related to the morphological characteristics observed by scanning electron microscopy.
Properties of Selected Polymers after Radiation Cross-linking
2012
Radiation processing involves the use of natural or manmade sources of high energy radiation on an industrial scale. The principle of radiation processing is the ability of high energy radiation to produce reactive cations, anions and free radicals in materials. The industrial applications of the radiation processing of plastics and composites include polymerization, cross-linking, degradation and grafting. Radiation processing mainly involves the use of either electron beams from electron accelerators or gamma radiation from Cobalt-60 sources. The TPE-E thermoplastic elastomer, LDPE low density polyethylene and PA6 polyamide 6 tested showed significant changes of temperature stability and mechanical properties after irradiation. From this point-of-view, new applications could also be seen in areas with service temperatures higher than their former melting point. The comparison of the temperature stability and mechanical properties of irradiated and nonirradiated TPE-E, LDPE and PA6...
Influence of γ‐irradiation on poly(methyl methacrylate)
Journal of Applied Polymer Science, 2002
Poly(methyl methacrylate) (PMMA) was γ‐irradiated (5–20 kGy) by a 137Cs source at room temperature in air. The changes in the molecular structure attributed to γ‐irradiation were studied by mechanical testing (flexure and hardness), size‐exclusion chromatography, differential scanning calorimetry, thermal gravimetric analysis, and both Fourier transform infrared and solution 13C‐NMR spectroscopy. Scanning electron microscopy was used to investigate the influence of the dose of γ rays on the fracture behavior of PMMA. The experimental results confirm that the PMMA degradation process involves chain scission. It was also observed that PMMA presents a brittle fracture mechanism and modifications in the color, becoming yellowish. The mechanical property curves show a similar pattern when the γ‐radiation dose increases. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 886–895, 2002