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Cucumber (Cucumis sativus L.) is a major vegetable crop grown globally, with a cultivation history of more than 3000 years. The limited genetic diversity, low rate of intraspecific variation, and extended periods of traditional breeding have resulted in slow progress in their genetic research and the development of new varieties. Gamma (γ)-ray irradiation potentially accelerates the breeding progress; however, the biological and molecular effects of γ-ray irradiation on cucumbers are unknown. Exposing cucumber seeds to 0, 50, 100, 150, 200, and 250 Gy doses of 60Co-γ-ray irradiation, this study aimed to investigate the resulting phenotype and physiological characteristics of seedling treatment to determine the optimal irradiation dose. The results showed that low irradiation doses (50–100 Gy) enhanced root growth, hypocotyl elongation, and lateral root numbers, promoting seedling growth. However, high irradiation doses (150–250 Gy) significantly inhibited seed germination and growth, decreasing the survival rate of seedlings. More than 100 Gy irradiation significantly decreased the total chlorophyll content while increasing the malondialdehyde (MDA) and H2O2 content in cucumber. Transcriptome sequencing analysis at 0, 50, 100, 150, 200, and 250 Gy doses showed that gene expression significantly differed between low and high irradiation doses. Gene Ontology enrichment and functional pathway enrichment analyses revealed that the auxin response pathway played a crucial role in seedling growth under low irradiation doses. Further, gene function analysis revealed that small auxin up-regulated gene CsSAUR37 was a key gene that was overexpressed in response to low irradiation doses, promoting primary root elongation and enhancing lateral root numbers by regulating the expression of protein phosphatase 2Cs (PP2Cs) and auxin synthesis genes.Key message: Low doses of γ-ray irradiation promoted seedling growth; CsSAUR37 was identified and overexpression of CsSAUR37 was found to promote primary root elongation and hypocotyl elongation, and increases in lateral root numbers; Cucumber exhibited phenotypic variations under γ-ray irradiation. These findings provided a foundation for constructing cucumber mutant libraries and excellent materials for understanding the mechanisms underlying γ-ray irradiation. [ABSTRACT FROM AUTHOR]

In this study, Poly(vinyl alcohol)/cellulose nanofiber (PVA/CNF) hydrogels have been successfully prepared using γ-ray irradiation, annealing, and rehydration processes. In addition, the effects of CNF content and annealing methods on the hydrogel properties, including gel fraction, micromorphology, crystallinity, swelling behavior, and tensile and friction properties, are investigated. Consequently, the results show that at an absorbed dose of 30 kGy, the increase in CNF content increases the gel fraction, tensile strength, and elongation at break of irradiated PVA/CNF hydrogels, but decreases the water absorption. In addition, the cross-linking density of the PVA/CNF hydrogels is significantly increased at an annealing temperature of 80 °C, which leads to the transition of the cross-sectional micromorphology from porous networks to smooth planes. For the PVA/CNF hydrogel with a CNF content of 0.6%, the crystallinity increases from 19.9% to 25.8% after tensile annealing of 30% compared to the original composite hydrogel. The tensile strength is substantially increased from 65.5 kPa to 21.2 MPa, and the modulus of elasticity reaches 4.2 MPa. Furthermore, it shows an extremely low coefficient of friction (0.075), which suggests that it has the potential to be applied as a material for artificial joint cartilage. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ion chromatography was used to investigate the effects of γ-ray irradiation dose, vitamin C (VC) content and niacinamide content on nitrite degradation in aqueous solution and spiced donkey meat, and the volatile components of irradiated spiced donkey meat were analyzed by gas chromatography-ion mobility spectrometry. The results showed that γ-ray irradiation could effectively degrade nitrite in both aqueous solution and spiced donkey meat. A synergistic effect was observed when γ-ray irradiation and VC were used together. Nicotinamide had an inhibitory effect on the irradiation degradation of nitrite in aqueous solution, but had a synergistic effect on the irradiation degradation of nitrite in spiced donkey meat. Nitrite ions in aqueous solution were converted to nitrate ions by the irradiation. After 8 or 10 kGy irradiation, the contents of hexanal and heptanal increased, and donkey meat had an off-flavor. This study provides technical support and a theoretical basis for the degradation of nitrite in spiced donkey meat by γ-ray irradiation.

In this study, Poly(vinyl alcohol)/cellulose nanofiber (PVA/CNF) hydrogels have been successfully prepared using γ-ray irradiation, annealing, and rehydration processes. In addition, the effects of CNF content and annealing methods on the hydrogel properties, including gel fraction, micromorphology, crystallinity, swelling behavior, and tensile and friction properties, are investigated. Consequently, the results show that at an absorbed dose of 30 kGy, the increase in CNF content increases the gel fraction, tensile strength, and elongation at break of irradiated PVA/CNF hydrogels, but decreases the water absorption. In addition, the cross-linking density of the PVA/CNF hydrogels is significantly increased at an annealing temperature of 80 °C, which leads to the transition of the cross-sectional micromorphology from porous networks to smooth planes. For the PVA/CNF hydrogel with a CNF content of 0.6%, the crystallinity increases from 19.9% to 25.8% after tensile annealing of 30% compared to the original composite hydrogel. The tensile strength is substantially increased from 65.5 kPa to 21.2 MPa, and the modulus of elasticity reaches 4.2 MPa. Furthermore, it shows an extremely low coefficient of friction (0.075), which suggests that it has the potential to be applied as a material for artificial joint cartilage.

Simple Summary: Animal feeds contain a substantial number and diversity of microorganisms due to bacterial contamination during processing, transportation, and storage, and some of them have pathogenic potential. To test the effect of gamma (γ)-ray irradiation on the elimination of bacteria in different feeds, we treated fishmeal, feather meal, meat meal, soybean meal, and vitamin complexes with graded doses of γ-ray irradiation. We found that a dose of 6–9 kGy was sufficient to eliminate most of the bacteria in the investigated feed. We also found that fishmeal with a high bacterial load and Escherichia coli (E. coli) contamination induced an increased diarrhea index and impaired the growth performance of weaning piglets but that these effects were reduced by γ-ray irradiation treatment at 6 kGy. These findings demonstrate that γ-ray irradiation can be used to treat feeds with biosafety concerns. Animal feeds contain a substantial number and diversity of microorganisms, and some of them have pathogenic potential. The objectives of this study were to investigate the effects of different doses of gamma (γ)-ray irradiation on the bacteria count in different types of feed and then to test the effect of γ-ray-irradiation-treated fishmeal on the gut health and growth performance of weaning piglets. In trial 1, three fishmeal samples, two feather meal samples, three meat meal samples, three soybean meal samples, and three vitamin complexes were treated with γ-ray irradiation doses of 0, 3, 6, or 9 kGy. The 6 and 9 kGy doses eliminated most of the bacteria in the feed but also resulted in a loss of vitamin C and B1. In trial 2, 96 weaning piglets were fed one of the following three diets with eight replicates (pens) per group over a 14-day period: (1) the control diet—the basal diet supplemented with 6% fishmeal with a low bacteria count (40 CFU/g) and no E. coli; (2) the fishmeal-contaminated diet (FM-contaminated) diet—the basal diet supplemented with 6% fishmeal with a high bacteria count (91,500 CFU/g) and E. coli contamination; and (3) the irradiated fishmeal (irradiated FM) diet—the basal diet supplemented with γ-ray-irradiation-treated E. coli-contaminated fishmeal. The piglets that received the FM-contaminated diet had significantly lower average daily gain and a greater diarrhea index compared to those fed the control diet, whereas γ-ray irradiation treatment abrogated the negative effect of the E. coli-contaminated fishmeal. Collectively, γ-ray irradiation at a dose of 6–9 kGy was sufficient to eliminate the microorganisms in the feed, thereby benefitting the growth performance and gut health of the weaning piglets. [ABSTRACT FROM AUTHOR]

Trans‐1,4‐polyisoprene (TPI) is a typical polymorphic polymer with two crystal modifications. The transition between two crystal modifications (α to β) occurs during stretching. The underlying mechanism is still under debate. In this work, the effects of crosslinking and strain rates on the crystal transition are studied. The TPI, which mainly contains α crystal (α−TPI), is crosslinked by γ‐ray radiation. The results show that crystalline morphology does not change after radiation. The melting temperature and yield stress of crosslinked α−TPI decrease with the irradiation dose. The structural evolution is studied by in situ wide‐angle X‐ray diffraction and small‐angle X‐ray scattering. During stretching, the content of β crystal (Xβ) of crosslinked α−TPI increases in the strain‐hardening region. The Xβ is lower in the sample with a higher radiation dose under the same strain. On the other hand, with increasing strain rate, the Xβ of the crosslinked sample exhibits a non‐monotonic variation. A parallel mechanical model consisting of amorphous and crystal fibrils is proposed to explain the experimental observations. [ABSTRACT FROM AUTHOR]

In this study the graphene oxide modified carbonyl iron (GO‐CI) was prepared by γ‐ray irradiation, which was added to silicone rubber composites to enhance the nuclear radiation shielding performances. X‐ray diffraction (XRD) characterization result showed the structure and morphology of the obtained GO‐CI nanocomposites. The mixture of GO/CI and the hybrid GO‐CI were individually incorporated into the vinyl‐terminated polydimethylsiloxane (Vi‐PDMS) to prepare referenced SR/GO/CI and SR/GO‐CI composites. Compared with SR/GO/CI, the SR/GO‐CI exhibited better thermal conduction and mechanical recovery properties. Moreover, the γ‐ray radiation shielding ability of SR/GO‐CI is much higher than that of pristine SR/GO/CI. CI particles are coated by GO nanosheets to increase surface area to prevent sedimentation of CI. It implies that SR‐GO/CI composite would have potential application as the radiation hardening material with thermal conductive and nuclear radiation shielding function. [ABSTRACT FROM AUTHOR]

Chilled pigeon meat was irradiated with different doses of 60Co-γ rays, and the effect of irradiation on the quality and lipid oxidation of chilled pigeon meat was investigated through the determination of biochemical and physicochemical indexes, volatile flavor components and microstructure observation. The results showed that with an increase in irradiation dose, the a* value, total volatile basic nitrogen (TVB-N) value, juice loss percentage, peroxide value (POV), thiobarbituric acid reactive substances (TBARS) value and acid value increased significantly (P < 0.05), and total bacterial number (TBN), L* value, b* value and texture parameters decreased significantly (P < 0.05); the diameter of muscle fibers decreased significantly (P < 0.05) and the gap between muscle fibers increased; and the contents of total, saturated and monounsaturated fatty acids increased significantly (P < 0.05), while the contents of polyunsaturated fatty acids decreased significantly (P < 0.05), indicating that irradiation treatment can promote the oxidative hydrolysis of lipids into free fatty acids and the decomposition of polyunsaturated fatty acids in pigeon meat. A total of 73 volatile components belonging to 8 chemical classes were detected in pigeon meat. Among them, hydrocarbons and aldehydes were most abundant, indicating that lipid oxidation has an important impact on the flavor of irradiated pigeon meat. The results of this study can provide a theoretical basis for the application of irradiation in the processing of livestock and poultry meat.

To explore the effects of absorbed dose and particle size on enzymatic hydrolysis and fermentation of reed straws (Phragmites australias), the straws were irradiated with γ-ray irradiation at different doses (0-500 kGy) and then passed through different aperture sieves after mechanical grinding. The effects of absorbed doses and sieving aperture size on particle size distribution, comminution energy, main component content, enzymatic hydrolysis conversion rate, and ethanol conversion rate of cellulose were examined, and the optimal respective sieving aperture for reed straws with different absorbed doses were determined. The results showed that with decreasing sieve aperture size, reed straw quality decreased significantly and was negatively correlated with the absorbed dose; the comminution energy of reed straws decreased with increasing absorbed doses. With respect to consistent quality of sieved reed straws, the comminution energy increased significantly with decreasing sieving particle size. In reed straws with the same absorbed dose, the enzymatic hydrolysis conversion rate and ethanol conversion rate of cellulose increased with decreasing sieving aperture size. Compared with reed straws with particle size r ˂ 0.850 mm, the cellulose enzymatic hydrolysis conversion rates in reed straws with particle size r ˂ 0.180 mm increased by 129.20%, 85.98%, and 106.63% at absorbed doses of 0 kGy, 206 kGy, and 404 kGy, respectively, and cellulose ethanol conversion increased by 136.04%, 21.75%, and 4.39%, respectively. By compre- hensively comparing the increased ratios of comminution energy, cellulose enzymatic hydrolysis conversion rate, and cellulose ethanol conversion rate, the optimal sieving aperture of non-irradiated (0 kGy) reed straws was deter-mined to be 0.850 mm, and that of reed straws irradiated with 206 kGy or 404 kGy was determined to be 0.425 mm.

In this study, graphdiyne was prepared using a γ-irradiated N-doping photogram to transform two-dimensional graphdiyne into a one-dimensional tubular structure for use as substrate-supported iron nanoparticles for cathodic redox reaction (ORR) in fuel cells. Methods such as scanning electron microscopy, X-ray diffraction, Raman spectroscopy, and isothermal nitrogen adsorption and other characterization methods were used to characterize and analyze the surface morphology, element composition, crystalline structure, and defect degree of the prepared composites. In the alkaline solution, the prepared catalyst was characterized by ORR performance, four-electron selectivity, kinetics and stability via cyclic voltammetry test, linear sweep voltammetry test and electrochemical AC impedance spectroscopy test. The results showed that after γ-ray irradiation, the nitrogen-doped graphite monoalkyne-loaded iron nanoparticle (NGY-Fe) catalyst had a larger specific surface area (411.3 m2/g) and a multilevel pore structure, which was conducive to the exposure of the active center. Moreover, the O2 permeation barrier was decreased, and the ORR activity of the NGY-Fe was significantly improved, especially in terms of the stability and methanol resistance, which were far superior to those of the commercially available commercial Pt/C catalysts.

The yolk-shell MIL-125/TiO2/ Pt/CdS and hollow TiO2/Pt/CdS visible-light catalysts were successfully synthesized from MIL-125 by γ-ray irradiation. During the reduction process by γ-ray irradiation, metal organic frameworks are partially or completely hydrolyzed to TiO2 nanosheets, forming the unique yolk-shell or hollow structure. The hydrogen production rate is 2.9835 mmol·g−1·h−1 for yolk-shell structures and 1.9342 mmol·g−1·h−1 for hollow structures under visible-light illumination, which is 7.9 and 5.1 times higher than that of CdS, respectively. The excellent properties of these photocatalysts may be attributed to the effective absorption and utilization of the light, the porous yolk-shell or hollow structure derived from MIL-125 to facilitate mass transfer, and close contact among CdS nanoparticles, TiO2 nanosheets and Pt nanoparticles to improve the separation of electron-hole pairs. This research can provide a simple and new method for the construction of high efficiency photocatalysts derived from MOFs using the γ-ray irradiation. [ABSTRACT FROM AUTHOR]

The stability of polymer materials used in nuclear environment directly determines the life and reliability of nuclear power equipment. Poly (aryl ether ketone) (PAEK) itself exhibits excellent irradiation resistance which can be widely used. The emphasis of this study lies in designing and synthesizing three different structures of amorphous PAEKs by the solution SN2 nucleophilic polycondensation. The thermodynamic properties and structural changes of the materials under gamma‐ ray (γ‐ray) irradiation were investigated and the irradiation‐resistance mechanism was discussed. The present results illustrate that the performance can be basically stable lower than 108 Gy. Up to 1013 Gy dose, γ‐ray has little effect on the impact resistance and Young ′s modulus of the three materials, the tensile strength and elongation at break decreased with the increase of irradiation dose. No new structures were formed after irradiation, and all the three materials decomposed slightly caused by oxidized. [ABSTRACT FROM AUTHOR]

γ-Irradiation and synchrotron-radiation-based X-ray absorption fine-structure (XAFS) spectroscopy have been used to induce structure disorder through the interaction of γ-rays (200 kGy) with fabricated Mn-doped ZnO nanoparticles (NPs) and then to examine thoroughly the resultant structural change. The extracted electronic/fine XAFS structural parameters reflect a compositional and γ-irradiation co-dependence. The average crystal structure of samples prepared by the sol-gel method was investigated by X-ray diffraction (XRD). A detailed structural XRD data analysis was carried out by applying a Rietveld refinement using the MAUD program. XAFS spectra were collected at the Zn K-edge (9659 eV) in transmission mode and at the Mn K-edge (6539 eV) in fluorescence mode. Direct evidence of the solubility of Mn ions in the ZnO structure was demonstrated by fitting the extended-XAFS (EXAFS) signal. Near-edge XAFS (XANES) analysis provided the oxidation states of Zn and Mn ions through fingerprint XANES spectra of the sample along with those of standard compounds. Linear combination fitting showed that the most fit chemical forms of Zn and Mn in the samples are ZnO and MnO, respectively. The oxidation states of both Zn and Mn XAFS absorbers were confirmed from pre-edge fitting. The results of the magnetic measurements were explained in light of the average and electronic/local structural information obtained from XRD, XANES and EXAFS techniques. The magnetic properties of the samples translate into an induced change in the average crystal and electronic/local structures upon Mn concentration change and γ-irradiation. XRD confirmed the successful preparation of hexagonal Mn-doped ZnO NPs with a crystallite size in the range 33–41 nm. Both XRD and EXAFS analysis detected a minor amount of Mn3O4 as a secondary phase. XANES and EXAFS provided information exploring the outstanding potential of the utilized protocol for detecting precisely the presence of the secondary phase of Mn3O4, which changes with Mn content (x). Mean-square relative displacement (σ2) values extracted from the EXAFS fitting were found to grow for Zn–Zn/Mn paths demonstrating the substitution of Mn/Zn into Zn crystal sites. The EXAFS analysis explains the reasons behind the enhancement in the magnetic properties and shows that the Mn doping content at x = 0.05 produces the most local atomic disorder in ZnO NPs. There is a strong harmony among the XRD, XANES, EXAFS and magnetization behavior of the Mn-doped ZnO NPs. Maximum magnetization was acquired at an Mn content of 0.05. γ-Ray-irradiated Zn1–xMnxO NPs are recommended as optimized candidates for showing the diversity of the applications.

Ionizing radiation damages DNA and may lead to the development of cancer. Irradiation also generates reactive oxygen species (ROS) which cause damage to various biological molecules. Relatively low dose‐rate irradiation causes less damage. However, the damage and its effects on cell fate are difficult to evaluate. To develop a method to analyze the damage and accompanying changes in physiology in cells irradiated by γ‐rays at a relatively low dose‐rate, we used the protein array technique to quantify marker proteins involved in the stress response and the regulation of cell growth and death. This method enabled efficient analyses of many replicates of experimental data on cell lysate samples. We detected relatively small changes in the levels of these proteins in the irradiated cells. Changes in protein levels suggested ROS production and DNA damage as well as cell cycle retardation and the progression of cellular senescence. Thus, our approach shows promise for analyzing the biological effects of relatively low dose‐rate irradiation. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Animal feeds contain a substantial number and diversity of microorganisms, and some of them have pathogenic potential. The objectives of this study were to investigate the effects of different doses of gamma (γ)-ray irradiation on the bacteria count in different types of feed and then to test the effect of γ-ray-irradiation-treated fishmeal on the gut health and growth performance of weaning piglets. In trial 1, three fishmeal samples, two feather meal samples, three meat meal samples, three soybean meal samples, and three vitamin complexes were treated with γ-ray irradiation doses of 0, 3, 6, or 9 kGy. The 6 and 9 kGy doses eliminated most of the bacteria in the feed but also resulted in a loss of vitamin C and B1. In trial 2, 96 weaning piglets were fed one of the following three diets with eight replicates (pens) per group over a 14-day period: (1) the control diet—the basal diet supplemented with 6% fishmeal with a low bacteria count (40 CFU/g) and no E. coli; (2) the fishmeal-contaminated diet (FM-contaminated) diet—the basal diet supplemented with 6% fishmeal with a high bacteria count (91,500 CFU/g) and E. coli contamination; and (3) the irradiated fishmeal (irradiated FM) diet—the basal diet supplemented with γ-ray-irradiation-treated E. coli-contaminated fishmeal. The piglets that received the FM-contaminated diet had significantly lower average daily gain and a greater diarrhea index compared to those fed the control diet, whereas γ-ray irradiation treatment abrogated the negative effect of the E. coli-contaminated fishmeal. Collectively, γ-ray irradiation at a dose of 6–9 kGy was sufficient to eliminate the microorganisms in the feed, thereby benefitting the growth performance and gut health of the weaning piglets.

The Ca-based organic framework (Ca-SINAP-1) loaded with silver was successfully prepared, which has a certain γ-ray irradiation resistance of 50 kGy. X-ray diffraction, scanning electron microscopy, Brunauer-Emmett-Teller specific surface area analysis, and pore volume analysis were used to characterize the sample and its Xe adsorption capacity. The results showed that loading of silver on the sample surface did not change the original structure of Ca-SINAP-1. However, the Xe uptake reached a maximum of 3.29 mmol/g and the Xe/Kr separation coefficient was 10.71 when silver loading was 0.93%. With increasing AgNO3 concentration in ethanol, the Xe adsorption quantity decreased because excess silver loading blocked the channels, and thus prevented Xe adsorption. The good irradiation resistance and high Xe/Kr selectivity make Ca-SINAP-1 a potential material for treating radioactive off-gas emitted from molten salt reactors.

The effects of γ-ray irradiation on the thermal stability and creep resistance of ultra-high molecular weight polyethylene (UHMWPE) were studied. First, UHMWPE powder was hot pressed into 1 mm thick sheets using a vulcanization molding machine. The chemical structure, thermal stability, microstructure, tensile properties, and creep properties of the irradiated plate samples were studied. The results demonstrated that, after γ-ray irradiation, the melting points, crystallinity, and thermal stability increased; the gel content increased to 89%; and the motility of molecular chains decreased. Compared with the creep resistance of the unirradiated sample, that of the irradiated sample increased by approximately 40%. In this study, the thermal stability and creep resistance of UHMWPE were significantly improved via the radiation cross-linking process, which provided a method for the preparation of UHMWPE materials with high creep resistance and high thermal stability.

During the long-term deep geological disposal of high-level radioactive waste, buffer materials, such as bentonite, in the waste repositories are irradiated with gamma (γ) rays, affecting their structural stability. Furthermore, bentonite colloids are formed owing to the erosion of bentonite particles by groundwater. However, the effects of prolonged irradiation on the stability of bentonite colloids and their interaction with radionuclides, which can affect the migration of the radionuclides, are yet to be elucidated. Herein, we investigated the stability of colloid prepared from irradiated bentonite with varying doses of γ rays and conducted static adsorption batch experiments to examine their U(VI) adsorption behavior. The results showed that the stability of bentonite colloids was affected by their concentration, storage time, pH, and temperature. An investigation into their polymerization kinetics revealed that the critical coagulation concentration of bentonite colloids decreased with increasing irradiation dose, indicating that the colloids formed from unirradiated bentonite were stable. Furthermore, the U(VI) adsorption capacity of bentonite colloids decreased with increasing irradiation dose. This study provides new insights into the formation and stability of colloids of buffer materials after their irradiation and is expected to contribute significantly to the study of the migration behavior of nuclides by colloidal carriers. [Display omitted] [ABSTRACT FROM AUTHOR]

• Dark current and low frequency noise increase in InGaAs avalanche photodiode after γ-ray irradiation. • The gamma-ray irradiation mainly increases the surface dark current in the dark current. • High temperature annealing can restore the dark current of the irradiated device. The γ-ray irradiation characteristics of InGaAs avalanche photodiode (APD) in a space radiation environment have been comprehensively investigated through an in-depth study. The results show that γ-ray can cause the dark current and low frequency noise of InGaAs APD to increase, while the avalanche breakdown characteristics, multiplication gain, spectral response and capacitance of the device are less affected by irradiation, and almost no obvious changes occur, which suggests that these parameters are insensitive to ionizing radiation. In addition, the activation energy of the device under different bias voltages is significantly increased by the ionization damage after irradiation. Finally, the annealing experiments at different temperatures after irradiation were carried out. It is found that the interface state induced by radiation is the main factor leading to the increase of dark current, low frequency noise and activation energy of InGaAs APD. Reducing the interface state can improve the device's ability to inhibit ionizing radiation damage. [ABSTRACT FROM AUTHOR]

The γ‐ray resistance of epoxy network polymers was evaluated. Bisphenol A diglycidyl ether (DGEBA) was used as an epoxy oligomer, and 4,4′‐diaminodiphenylmethane (DDM), hexahydrophthalic anhydride (HHPA), and phenolic novolac (PN) were used as curing agents. The thermally crosslinked polymers were irradiated with 0–10 MGy of γ‐rays. The crosslink density as well as the glass‐transition temperature (Tg) for the DDM‐cured and PN‐cured DGEBA resins decreased upon γ‐ray irradiation; however, the elastic modulus at room temperature and the density of the resins increased. By contrast, the Tg for the HHPA‐cured DGEBA resin increased slightly and the crosslink density decreased markedly when the specimen was irradiated with γ‐rays. Among the three cured systems, the HHPA‐cured DGEBA resin exhibited the greatest amount of gas generation during irradiation. Infrared absorption spectra revealed a decrease in the number of ester bonds and an increase in the number of aliphatic and aromatic ether bonds, suggesting that new crosslinking occurred concurrently with chain scission. Overall, among the three cured systems, the PN‐cured DGEBA resin was the most stable in terms of chemical structure and physical properties under γ‐ray irradiation. [ABSTRACT FROM AUTHOR]

γ-Irradiation and synchrotron-radiation-based X-ray absorption fine-structure (XAFS) spectroscopy have been used to induce structure disorder through the interaction of γ-rays (200 kGy) with fabricated Mn-doped ZnO nanoparticles (NPs) and then to examine thoroughly the resultant structural change. The extracted electronic/fine XAFS structural parameters reflect a compositional and γ-irradiation co-dependence. The average crystal structure of samples prepared by the sol-gel method was investigated by X-ray diffraction (XRD). A detailed structural XRD data analysis was carried out by applying a Rietveld refinement using the MAUD program. XAFS spectra were collected at the Zn K-edge (9659 eV) in transmission mode and at the Mn K-edge (6539 eV) in fluorescence mode. Direct evidence of the solubility of Mn ions in the ZnO structure was demonstrated by fitting the extended-XAFS (EXAFS) signal. Near-edge XAFS (XANES) analysis provided the oxidation states of Zn and Mn ions through fingerprint XANES spectra of the sample along with those of standard compounds. Linear combination fitting showed that the most fit chemical forms of Zn and Mn in the samples are ZnO and MnO, respectively. The oxidation states of both Zn and Mn XAFS absorbers were confirmed from pre-edge fitting. The results of the magnetic measurements were explained in light of the average and electronic/local structural information obtained from XRD, XANES and EXAFS techniques. The magnetic properties of the samples translate into an induced change in the average crystal and electronic/local structures upon Mn concentration change and γ-irradiation. XRD confirmed the successful preparation of hexagonal Mn-doped ZnO NPs with a crystallite size in the range 33-41 nm. Both XRD and EXAFS analysis detected a minor amount of Mn3O4 as a secondary phase. XANES and EXAFS provided information exploring the outstanding potential of the utilized protocol for detecting precisely the presence of the secondary phase of Mn3O4, which changes with Mn content (x). Mean-square relative displacement (σ2) values extracted from the EXAFS fitting were found to grow for Zn-Zn/Mn paths demonstrating the substitution of Mn/Zn into Zn crystal sites. The EXAFS analysis explains the reasons behind the enhancement in the magnetic properties and shows that the Mn doping content at x = 0.05 produces the most local atomic disorder in ZnO NPs. There is a strong harmony among the XRD, XANES, EXAFS and magnetization behavior of the Mn-doped ZnO NPs. Maximum magnetization was acquired at an Mn content of 0.05. γ-Ray-irradiated Zn1-xMnxO NPs are recommended as optimized candidates for showing the diversity of the applications. [ABSTRACT FROM AUTHOR]

Up to now, facile and pollution-free routes for catalyst preparation are in high demand. In this study, a green and cost-effective strategy was successfully developed to construct platinum/graphene aerogel (Pt/GA) nanocomposites by the co-reduction of graphene oxides (GO) and chloroplatinic acid (H2PtCl6·6H2O) with the assists of γ-ray irradiation in the absence of any other reductants. Characterization studies indicated that the energy of γ-ray irradiation and the hole scavenger isopropanol (IPA) played a vital role in forming small Pt nanoparticles with uniform size of ∼3 nm on the surface of graphene aerogel (GA). Furthermore, Pt/GA synthesized with a mass ratio of 2:1 (Pt/GA-2) exhibited a lowest activation energy value and outstanding catalytic properties for the reduction of 4-nitrophenol (4-NP). The excellent catalytic and cycling performance suggest that Pt/GA-2 catalyst has a promising prospect for the reduction of nitroaromatic compounds in wastewater treatment and other industrial applications.

The serious damage caused to 3D braided carbon fiber (CF)/epoxy (EP) composites in high-energy irradiation environments is a pressing research topic that has not yet been reported. This study analyzed the γ-irradiation multi-scale damage of the matrix, interfaces, and near-interface regions in 3D braided CF/EP composites with three different braiding angles (18°, 28°, 38°) at atomic, microscopic, and macroscopic scales. The molecular structure and atomic charge information alterations of epoxy matrix were characterized using soft X-ray absorption spectroscopy (sXAS). When the irradiation dose reached 1000 KGy, the compressive strength of composites decreased by 20.88 %, 18.07 %, and 16.60 %, respectively, with an increase in the braiding angle. Micro-CT observation, along with statistical computing, confirmed that irradiation causes interface damage and increases the defect volume of 3D braided composites. Nanoindentation was used to compare the modulus of carbon fiber, interface, near-interface regions and matrix in irradiated composites and the function of CF/resin interface as an irradiation defect capture site in the irradiation resistance of resin-matrix composites has been newly established. In addition, the mechanism behind the effect of braiding angle on macroscopic properties was also analyzed. [Display omitted] • The braided structures exhibited varying responses to irradiation, with 3D-38° showing the highest performance retention. • Soft X-ray absorption spectrometry was developed to characterize the valence changes of oxygen and carbon in irradiated resin. • Interface as an irradiation defect capture site consumes most of the energy and reduces the damage of resin near the interface. [ABSTRACT FROM AUTHOR]

Bentonite was irradiated with 60Co γ-rays at a dose rate of 10 kGy/h to achieve irradiation doses of 1, 2, 3 MGy and was characterized to evaluate its stability before and after irradiation and understand the radiation damage mechanism. The structure of the bentonite was slightly affected by high doses of irradiation, and the U(VI) adsorption capacity of the irradiated bentonite was reduced compared to that of raw bentonite. Overall, this study provides insights into the negative effects of high-dose γ-ray irradiation on the stability and adsorption capacity of bentonite, which has safety implications for the storage of radioactive waste. [ABSTRACT FROM AUTHOR]

More reliable and long-term irradiation stability is essential for lubrication protection materials that served in nuclear energy equipment. In this paper, three typical commercially organic bonded solid lubricating coatings were chosen to investigate the influence of gamma (γ)-ray irradiation on microstructure and tribological behaviors. The evolution of microstructure and the changes of tribological properties for these coatings after irradiation were comparatively studied in detail. The results revealed that the crystallinity of the molybdenum disulfide (MoS 2) lubricating phase was improved and were partial oxidized in the coatings after γ-ray irradiation, resulting in the surface roughness of the coating with MoS 2 as the solid lubricating phase decreased significantly. The polytetrafluoroethylene (PTFE) lubricating phase was degraded from the long chains structure to smaller molecules after γ-ray irradiation. The results of tribological properties of the three coatings after γ-ray irradiation indicated that, for polyamide-imide-based lubricating coatings, the friction coefficient is decreased and the wear rate is increased after irradiation. For phenolic epoxy-based lubricating coating, the cross-linking effect of γ-ray irradiation predominated to improve the wear resistance and prolong the wear life of the coating. But overall, the influence of irradiation on tribological properties of three polymer-based coatings could almost be neglected duo to the changes of the microstructure in nanoscale. This work provides path and direction for design and preparation of the lubricating coatings that served in a nuclear reactor. • The crystallinity of the MoS 2 lubricating phase was improved after γ-ray irradiation • For polyamide-based coatings, the friction coefficient is decreased and the wear rate is increased after irradiation • For epoxy-based coating, the cross-linking effect of γ-ray irradiation predominated to improve the wear resistance and prolong the wear life • The degradation and cross-linking effects have occurred only in shallow surface [ABSTRACT FROM AUTHOR]

BackgroundCyclic olefin copolymer (COC), synthesized by catalytic copolymerization of ethylene and norbornene, can be applied in medical devices and drug packaging, owing to its many outstanding properties such as good light transmittance, water vapor barrier and biocompatibility. When this type of medical devices or drug package is sterilized by high energy irradiation, COC will inevitably undergo changes such as radiation scission, oxidation, discoloration and so on. It is of great significance to explain the performance change of COC from the free radical reaction initiated by ionization radiation for the radiation sterilization application of COC medical supplies.PurposeThis study aims to investigate radiation effect of COC in the dose range of radiation sterilization.MethodsEffects of γ-rays on chemical structure, free radical, glass transition temperature, thermal stability, molecular weight distribution, surface properties and melt index of the irradiated COC with the sterilization dose were investigated by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible absorption spectroscopy (UV-vas), electron spin resonance spectroscopy (ESRS), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), gel permeation chromatography (GPC), water contact angle (WCA) and melt mass-flow rate measurement.ResultsThe concentration of free radicals produced by COC irradiation in air increases linearly with the increase of absorbed dose. With the increase of absorbed dose, radiation degradation is dominant, hence the average molecular weight of the radiation oxidation products include carbonyl and hydroxyl compounds decreases, and the surface hydrophilicity is enhanced whilst the melt index is increased.ConclusionsThe molecular chain breakage caused by radiation and the reaction between free radicals and oxygen are the main causes of COC degradation.

Polymer dielectric capacitors are fundamental in advanced electronics and power grids but suffer from low energy density, hindering miniaturization of compact electrical systems. It is shown that high-energy and strong penetrating γ-irradiation significantly enhances capacitive energy storage performance of polymer dielectrics. γ-irradiated biaxially oriented polypropylene (BOPP) films exhibit an extraordinarily high energy density of 10.4 J cm -3 at 968 MV m -1 with an efficiency of 97.3%. In particular, an energy density of 4.06 J cm -3 with an ultrahigh efficiency of 98% is reliably maintained through 20 000 charge-discharge cycles under 600 MV m -1 . At 125 °C, the γ-irradiated BOPP film still delivers a high discharged energy density of 5.88 J cm -3 with an efficiency of 90% at 770 MV m -1 . Substantial improvements are also achieved for γ-irradiated cycloolefin copolymers at a high temperature of 150 °C, verifying the strategy generalizability. Experimental and theoretical analyses reveal that the excellent performance should be related to the γ-irradiation induced polar functional groups with high electron affinity in the molecular chain, which offer deep energy traps to impede charge transport. This work provides a simple and generally applicable strategy for developing high-performance polymer dielectrics., (© 2024 Wiley‐VCH GmbH.)

BackgroundThe adsorption and separation of Xenon (Xe) / Krypton (Kr) has received increasing attention due to the concern of reprocessing radioactive isotopes of Xe and Kr from off-gas of used nuclear fuel as well as the commercial value of high purity Xe gas. At present, the separation of Xe/Kr is mainly through cryogenic distillation, which is energy and capital intensive. Porous materials such as metal-organic frameworks (MOFs) have shown the ability to selectively adsorb xenon and krypton at relative high temperature, hence are expected to replace cryogenic distillation to achieve low-cost Xe/Kr separation.PurposeThis study aims to investigate the gamma radiation stability of three MOFs (Co/DOBDC, Ni/DOBDC, Co3(HCOO)6) used for Xe and Kr adsorption separation.MethodsFirst of all, three MOFs, i.e., Co/DOBDC, Ni/DOBDC, and Co3(HCOO)6, were synthesized and activated according to the preparation methods in the published literature, and the adsorption isotherms of Xe and Kr in three MOFs samples were measured by using physical adsorption instrument with a specially designed water circulating system to maintain a constant temperature (273 K). Then, these samples were irradiated with γ-ray (1.322 MeV) at a gamma dose rate of 0~1 kGy·h-1 at ambient temperature. Samples' properties, such as Henry constant, Henry selectivity and ideal adsorbed solution theory (IAST) selectivity of Xe/Kr, before and after irradiation, were characterized by X-ray diffraction (XRD) patterns and N2 adsorption measurements. Finally, the γ-ray radiation stability of Co/DOBDC, Ni/DOBDC and Co3(HCOO)6 were studied, and the pore properties (specific surface area and pore volume) before and after irradiation were compared.Results & ConclusionsExperimental results from the observed single-component Xe and Kr isotherms, Henry's constants, Henry's constant ratio and IAST selectivity of the sample, show that Co/DOBDC and Ni/DOBDC as adsorbents have the potential to adsorb and storage high concentration Xe whilst Co3(HCOO)6 has the potential for adsorption separation of Xe and Kr in low concentration. Radiation resistance test results show that the pore properties of Co/DOBDC and Ni/DOBDC change significantly after different doses of γ-ray irradiation, and the change degree of pore properties of Co/DOBDC is large than that of Ni/DOBDC whilst the pore properties of Co3(HCOO)6 basically do not change after γ-ray radiation at a total dose of 9 kGy, indicating that Co3(HCOO)6 can be considered as a potential adsorbent for Xe/Kr separation under radioactive conditions.

• The ionization of atoms caused by γ-ray irradiation leads to generation and accumulation of E′ centers and NBOHCs in silica film. • γ-ray irradiation results in the reductions of Si-O-Si bond angle and bond length, thus causing the densification of silica film. • The refractive index and mechanical properties firstly enhance and then reduce with the increasing absorbed dose due to the densification of silica film. • The dose-dependent surface quality, defects and mechanical properties determine the variation in laser damage threshold of silica film. γ-ray radiation effect on sol-gel silica films was investigated at different absorbed doses ranging from 10 kGy to 1000 kGy. The defect and microstructure evolutions of silica films were analyzed to understand the performance degradation behavior and mechanism of the γ-ray irradiated silica films. The cracks appear on the silica film surface and further expand at larger γ-ray absorbed dose, while surface roughness slightly decreases. During γ-ray irradiation, the thermal effect and the increased rate of diffusion-controlled process lead to the condensation of Si-OH groups and the recombination of ODCs. However, the ionization of atoms leads to generation and accumulation of E′ centers and NBOHCs. γ-ray irradiation leads to the reductions of bond lengths and bond angles of Si-O-Si groups, thus causing the densification of films. The refractive index and mechanical property firstly enhance and then reduce with the increase of absorbed dose associated with the change of silica film density. After γ-ray irradiation, the decreased contact angle and increased surface free energy indicate the reduction of anti-pollution ability of silica films. The dose-dependent surface quality, defects and mechanical properties determine the variation in laser-induced damage threshold (LIDT) of silica film. The results provide a reference to control the structural damage and performance degradation of silica films, which is very important for the research of safe operation of high-power laser facilities for inertial confinement fusion (ICF). [ABSTRACT FROM AUTHOR]

Herein, 4,4′-bis(9 H -carbazol-9-yl) biphenyl (CRB) a known PhOLED was incorporated into bioplastic chitosan films (CHCRB) resulted in blue emissive composite films with high efficiency. This work presents the interesting change in optical properties of chitosan/CRB composite films wherein an insulator material has been converted into organic semiconductor material. The doping with CRB converted the non-emissive chitosan films as excellent deep blue light emissive materials which is of prime requirement for white LED. Upon irradiation, with gamma ray (15, 25, 45 kGy), the structural and morphological changes occurred in the fabricated films evidenced by analytical, spectroscopic and mechanical studies. The chitosan films exhibited UV absorption at λ max 301 nm (UVB) for unirradiated and broad absorption band at λ max 325 nm (UVA) for irradiated CHCRB films with energy band gap ranging from 2.83 to 2.03eV. Though the unirradiated films showed high intensity deep blue emission at λ max 392 nm with QY of 35.15%, photoluminescence intensity, decreased gradually to QY of 25.26% upon gamma ray irradiation in a dose dependent manner at λ max 392 nm.The quenching of fluorescence could be attributed to the photo induced electron transfer from chitosan to CRB under high energy irradiation. Spectroscopic evidences indicated by the appearance of a new absorption band in FTIR spectra at 1228 cm−1 and a peak at 401.7eV in XPS owing to the formation of quaternary nitrogen on CRB upon electron transfer. Also, colour measurement from CIE diagram indicated the material could also be used as blue emissive material in the devices. Hence, environmentally benign bioplastic films were prepared by simple technique which exhibited both UV absorbing and blue light emissive properties. This work proposes a way to make novel emissive bioplastic films which will be useful for optoelectronic as well as sensing applications. [Display omitted] • 4,4′-bis(9 H -carbazol-9-yl) biphenyl(CRB)was incorporated into bioplastic chitosan resulted in blue emissive films. • The photoluminescence property of these films showed interesting phenomenon of quenching in emission intensity. • The quenching of fluorescence could be attributed to the photo induced electron transfer under gamma ray irradiation. [ABSTRACT FROM AUTHOR]

In this research, the antimicrobial agent (sliver nanoparticles) (AgNPs) and bio-based poly(vinylpyrrolidone) (PVP) were introduced on the poly (lactic acid) (PLA) fabrics by γ-ray induced simultaneous grafting and reduction. The morphology and the AgNPs distribution of the modified PLA fabrics were investigated by scanning electron microscopy (SEM). The interaction of PLA fabrics, AgNPs and PVP was tested by X-ray photoelectron spectroscopy (XPS). It was indicated that AgNPs were coordinated with oxygen and nitrogen atoms of pyrrole rings, which was facilitated to be anchored firmly on PLA fabrics. The mechanical, hydrophilic and antibacterial properties of the modified PLA fabrics were also investigated. The modified PLA fabric (PLA- g -PVP-Ag-2) shown the similar mechanical strength to that of pure PLA. Besides, with the lower loadings of AgNPs, PLA- g -PVP-Ag-2 exhibited greatly enhanced hydrophilicity and antibacterial performance. The water wetting time was 19.3 s (the original PLA fabric was >90 s) and the antibacterial rate against S. aureus was >99 %. • The hydrophilic and antibacterial PLA fabric was prepared by grafting NVP and reducing AgNPs on PLA by γ-ray irradiation. • The interaction mechanism was the coordination interaction between AgNPs and PVP. • The antibacterial rate of the modified PLA fabric against S. aureus was > 99%. • The water wetting time of the modified PLA fabric was 19.3 s (the original PLA fabric was >90 s). [ABSTRACT FROM AUTHOR]

This study reports the impact of γ-ray exposure on the nanostructural, morphological, and optical characteristics of lead iodide (PbI 2) thin films (TFs). These PbI 2 were deposited on glass substrates using a spin coating technique. The γ-ray irradiation was carried out using Co-60 gamma source with dose range from 0 to 100 kGy. The X-ray diffraction (XRD) results revealed a decrease in crystallinity and an increase in crystallite size of PbI 2 as a function of γ-ray dose. Field emission scanning electron microscopy (FESEM) exhibited the variations in surface morphology with increasing γ-ray dose. The elemental composition of as prepared TFs was confirmed by energy dispersive X-rays (EDX) analysis. The optical transmission of PbI 2 TFs was evaluated with varying the γ-ray doses. The estimated energy band gap (Eg) reduced from 2.54 to 2.45 eV with γ-ray dose. Photoluminescence (PL) spectra represent a broad peak centered at 507.64 nm with a hump present at 519.73 nm in the as prepared sample, which grow gradually with increasing the γ-ray dose. The maximum value of mobility was found to be 10.48 cm2 V−1 s−1 at 50 kGy. The change in the mobility is associated with the density of structural defects influenced by γ-ray doses. These effects conclude that γ-irradiation played a key role in structural, electrical and optical properties of the PbI 2 TFs and proposes that the γ-irradiation response makes it a good candidate for radiation detecting material application. • The spin coating technique was employed deposit the PbI 2 thin films. • Thin films were irradiated with γ-ray using 60Co source with different dose level (0, 25, 50, 75, 100 kGy). • X-ray diffraction revealed that the crystallite size increased in with γ-ray dose. • The energy band gap of PbI 2 thin films dropped after irradiated. • The electrical conductivity and carrier concentration were enhanced with γ-ray doses. [ABSTRACT FROM AUTHOR]

Reduced graphene oxide (rGO) is supposed to have better stability and adsorption properties than graphene oxide (GO). Here, GO was controllable reduced by γ-ray irradiation at low doses of 0–10 kGy. Both physicochemical characteristics and filtration performance of GO/rGO membranes were investigated. The XPS, FTIR and UV spectra data showed that both the types and contents of the oxygen-containing functional groups changed after irradiation, but were not linearly correlated with the dose. The irradiation doses of 2 and 10 kGy were two important points, at which the largest C/O values were found. Although the types of the oxygen-containing functional groups were different, the rGO membranes at 2 and 10 kGy both showed the largest flux and the lowest rejection during the long-term filtration. The performance of the rGO membrane is highly influenced by the content rather than the types of oxygen-containing functional groups. The rGO membrane was more stable than the GO membrane at low GO load during the long-term filtration. The rejections of both dye and ions decreased along running time and adsorption was the main mechanism. Different performances were found for the long and short-term filtration. The balance of flux and rejection, as well as the long-term test should be paid more attention during the application of GO/rGO membranes. • GO was controllable reduced by γ-ray irradiation at low doses of 0–10 kGy. • The reduction degree was not linearly related with the irradiation dose. • The rGO at 2&10 kGy had the largest C/O value, largest flux and lowest rejection. • The rGO membrane was more stable than the GO membrane especially at low GO load. • Different performances were found for long and short term filtration. [ABSTRACT FROM AUTHOR]

The ferroelectric materials own the natural anti-irradiation property, paving great potentials and applications regarding the aerospace fields. Benefiting from this property, LiNbO 3 -based surface acoustic wave (SAW) devices can be used for high accuracy sensing signal test under extreme circumstances. In this work, the 128° YX cut LiNbO 3 substrate was adopted for SAW resonator temperature sensor application, and the response frequency varied from 180.44 MHz to 177.628 MHz with temperature from 21.9 ℃ to 199.9 ℃. Subsequently, the device irradiated by 100 Krad Gamma ray was tested with vector network analyzer (VNA). A maximum frequency shift of ~ 0.38% was found under γ-ray irradiation with a dose of 100 Krad on account of slight irradiation effect. The results verify the radiation resistance ability of SAW for development of highly reliable temperature sensor in the irradiation environment. A novel SAW temperature sensor was analyzed, designed and fabricated with 128°YX LiNbO3 process platform, which can be used for testing temperature under irradiation experiment. [Display omitted] • A SAW temperature sensor was fabricated by 128° YX cut LiNbO3 which could work under the irradiation experiment. • The sensor has good anti-irradiation property, that a maximum frequency shift of 0.38% was found under γ-ray irradiation. • The SAW temperature sensor was standardized and tested, and the device showed good stability. [ABSTRACT FROM AUTHOR]

[Display omitted] • γ–ray irradiation on solid-state lead Iodide precursor rearranges its structure. • Radicals induce a planar structure of lead iodide and high coordination with Pb ions. • High-valent iodoplumbates caused by γ–irradiated lead iodide improve perovskite crystalline properties. • The device with γ–irradiated perovskite exhibits high photocurrent owing to suppressed charge recombination. We describe an effective method for tuning the structure of lead iodide (PbI 2) via high-energy gamma (γ)-ray irradiation. The chemistry of the precursor used in preparing the solution critically determines the quality of the perovskite films and the photovoltaic performance. We investigated the dependence of the precursor crystal structure and morphology on the γ-ray irradiation dose without by-products. The crystal orientation of PbI 2 gradually changed when PbI 2 was exposed to γ-ray radiation, causing it to form high-valent iodoplumbates with organic solvents because of the increase in the Pb oxidation number required to maintain a planar structure. The iodoplumbates suppress rapid crystallization and limit the space available for the grains to grow, thereby improving perovskite crystallinity. We also analyzed the optical and electrical properties of a perovskite film containing the irradiated precursor and compared them with those of a film containing the pristine PbI 2 precursor. The detailed analysis of the crystal structure of the film revealed the effects of γ-ray irradiation. The PSC devices produced with γ-irradiated precursor material displayed improved performance. The direct treatment of precursors with high energy sources, such as γ-rays, which does not involve fabrication, is efficient in improving perovskite structures. [ABSTRACT FROM AUTHOR]

New polyurea coatings were synthesized using aromatic diphenylmethane diisocyanate, large molecular weight amino-terminated polyether, and appropriate additives. Fourier transform infrared (FTIR) spectroscopy and field emission scanning electron microscopy were used to examine the effects of γ-ray irradiation with different dose rates and cumulative doses on the microstructure of the new polyurea coatings. The variations of mechanical properties of the polyurea coatings before and after irradiation were studied using an electronic universal testing machine and a split Hopkinson compression bar. FTIR spectroscopy showed that the raw materials for preparing polyurea coatings had reacted completely, and polyurea had been synthesized. An analysis of the mechanical properties showed that the mechanical behavior of the new polyurea changed gradually from rubbery under a quasi-static load to glassy under a dynamic load, showing excellent impact resistance. The characteristic absorption peaks of the FTIR spectrum of polyurea did not change significantly before and after irradiation. However, the color of the polyurea changed from light yellow to dark red with decreasing dose rate or increasing cumulative dose, which is related to the radiation oxidation time. Some white fragments appeared after the polyurea was irradiated with γ-rays. The number of white fragments increased with decreasing dose rate or increasing cumulative dose, which may be caused by the soft segment embrittlement of polyurea under radiation oxidation. A comparison of the mechanical properties under different γ-ray irradiation conditions found that the newly synthesized polyurea coatings had good resistance to γ-ray radiation. Moreover, their performance was improved to a certain extent after irradiation. The performance of irradiated polyurea was optimum when the irradiation dose rate was 2 KGy/h, and the cumulative dose was 220 KGy. • The impact-resistant and irradiation-resistant polyurea is synthesized. • Quasi-static and dynamic mechanical properties of polyurea are studied. • Effect of γ-ray irradiation on microstructure morphology of polyurea is discussed. • Influence of γ-ray irradiation on the mechanical behavior of polyurea is analyzed. • Optimal irradiation condition for irradiation modification of polyurea is obtained. [ABSTRACT FROM AUTHOR]