电子束辐照剂量对PAN/PEO交联度的影响

对PAN/PEO凝胶(5%PAN,5%PEO)在1.0 MeV电子束下进行了不同剂量的辐照。红外光谱测量表明,PAN/PEO凝胶辐照后发生了化学交联。分析结果指出,PAN/PEO的凝胶分数随着辐照剂量的增加而不断增加;其凝胶分数增长率的变化可以分为3个阶段,即快速增加阶段(0~39kGy)、下降阶段(39~130 kGy)和稳定阶段(130 kGy)。拟合发现,引入材料刚性参数β的半经验修正方程与未考虑材料刚性的Char1esby-Pinner方程相比,更符合实际测量值(对于该配比PAN/PEO,β为0.166)。交联度-辐照剂量曲线显示,交联度随辐照剂量的增加而增加,为设计新型能功能材料中所需的固定交联度的PAN/PEO凝胶提供了辐照剂量参考值。     

Effect of gamma-irradiation on the structural,optical and electrical properties of PEO/starch blend containing different concentrations of gold nanoparticles

ABSTRACT

Blend of polyethylene oxide (PEO)/starch (70/30 wt.%) filled with different amounts of gold nanoparticles (AuNPs) were prepared using the casting technique. X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) techniques were used to investigate the structure of polymeric samples before and after exposing to gamma irradiation at different times. XRD showed a gradual decrease in intensity of crystalline peaks with increasing the gamma dose denotes a decrease in the amount of crystalline phase in the films, while the FTIR measurement shows induced changes in chemical structure assigned to the AuNPs amount and irradiation times. The optical energy gap values (E_g) for unirradiated and irradiated samples were calculated and interpreted. The differential scanning calorimetry (DSC) which showed the miscibility between the two components of the blend. The electrical conductivity (σ) measurement was showed increased in electrical conductivity after exposure to the gamma dose. The gold nanoparticles were used as nano?ller to improve the structural and electrical properties of polymeric samples. The results showed the Gamma irradiation significantly effect on the structural and electrical properties of PEO/starch blend.     

Effect of gamma irradiation on HPMC/ZnO nanocomposite films

The present work looks into the structural, chemical, mechanical, optical and thermal modification in ZnO nanoparticle incorporated hydroxypropyl methylcellulose (HPMC) polymer films, induced by gamma irradiation. The irradiation process was performed in a gamma chamber at room temperature using Cobalt-60 source (average energy of 1.25?MeV) at different doses: 0, 50, 100, 150 and 200?kGy. The modifications in structural, chemical, mechanical, optical and thermal properties, due to gamma irradiation in HPMC/ZnO nanocomposite films, have been studied using wide angle X-ray scattering (XRD), Fourier transform infrared spectroscopy, universal testing machine, ultraviolet–visible spectrophotometry and thermogravimetric analysis. It is found that gamma irradiation improves the mechanical and thermal properties of nanocomposite films.     

Enhancing mechanical properties of prevulcanized natural rubber latex via hybrid radiation and peroxidation vulcanizations at various irradiation doses

At present, there are three popular vulcanization processes being used in natural rubber latex industries, which are sulfur, radiation and peroxide vulcanization. Sulfur vulcanization produced products with superior mechanical properties compared to radiation and peroxide vulcanization. This paper discussed the effect of gamma irradiation dose on hybrid radiation and peroxidation vulcanizations in improving the mechanical properties of radiation vulcanized natural rubber latex (RVNRL). Latex compounding formulations are developed based on 2.5?parts per hundred rubber (phr) of hexanediol diacrylate (HDDA) as the sensitizer, 0.1?phr of tert-butyl hydroperoxide (t-BHPO) as the co-sensitizer and 2.5?phr of Aquanox LP antioxidant. The RVNRL was prepared and irradiated at various gamma radiation doses of 2, 4, 6, 8, 10 and 12?kiloGray (kGy). The rubber film obtained from irradiation at 6?kGy had tensile strength, modulus @ 500% and modulus @ 700% of 27.0, 3.0 and 11.0?MPa, respectively, which is more than 37% increment compared to the control film. Besides, the crosslink percentage of the rubber film showed 4% increment from 90% to 94%.     

Structural and optical modifications in gamma-irradiated polyimide/silica nanocomposite

The structural and optical properties of thin films of polyimide composites with nanosilica particle content of 15?wt%, prepared via sol–gel process, were studied as a function of the gamma dose. The resultant effect of gamma irradiation on the properties of polyimide/silica nanocomposite has been investigated using X-ray diffraction and UV spectroscopy. Absorption and reflectance spectra were collected by a spectrophotometer giving UV-radiation of wavelength range 200–800?nm. The optical data obtained were analyzed and the calculated values of the optical energy gap exhibited gamma dose dependence. The direct optical energy gap for the nonirradiated polyimide/silica nanocomposite is about 2.41?eV, and increases to a value of 2.65?eV when irradiated with gamma doses up to 300?kGy. It was found that the calculated refractive index of the polyamide/silica increases with the gamma dose in the range 50–300?kGy.     

Increased porous morphology and thermal degradation of electron beam-irradiated PVDF-HFP/LiCLO4 polymer electrolyte

The effect of 8?MeV energy electron beam radiation at 40, 80 and 120?kGy dosage on surface morphology and thermal properties of lithium perchlorate-doped poly (vinylidene fluoride-co-hexafluoropropylene) polymer electrolyte films have been studied. The field emission scanning electron microscopic image shows small-porous structured morphology for unirradiated film, but it changed drastically into large and deep porous structure as well as the size of spherulites is reduced for 120?kGy confirming the influence of irradiation on morphology. The atomic force microscope reveals the significantly changed surface roughness of unirradiated film from 116.8 to 123.4?nm with a hill-like pattern morphology for 120?kGy confirming the increased amorphousity after irradiation. The thermal study confirmed that the decrease in the melting point of unirradiated film 160.86–155.24°C for 120?kGy doses is attributed to the formation of defects by the chain scissioning process resulting in the degradation of polymer electrolytes at high dose.     

Ionic conductivity study on electron beam irradiated polyacrylonitrileben polyethylene oxide gel

Different mass percent polyacrylonitrile (PAN)—polyethylene oxide (PEO) gels were prepared and irradiated by an electron beam (EB) with energy of 1.0 MeV to the dose ranging from 13 kGy to 260 kGy. The gels were analysed by using Fourier transform infrared spectrum, gel fraction and ionic conductivity (IC) measurement. The results show that the gel is crosslinked by EB irradiation, the crosslinking degree rises with the increasing EB irradiation dose (ID) and the mass percents of both PAN and PEO contribute a lot to the crosslinking; in addition, EB irradiation can promote the IC of PAN—PEO gels. There exists an optimum irradiation dose, at which the IC can increase dramatically. The IC changes of the PAN—PEO gels along with ID are divided into three regions: IC rapidly increasing region, IC decreasing region and IC balanced region. The cause of the change can be ascribed to two aspects, gel capturing electron degree and crosslinking degree. By comparing the IC—ID curves of different mass percents of PAN and PEO in gel, we found that PAN plays a more important role for gel IC promotion than PEO, since addition of PAN in gel causes the IC—ID curve sharper, while addition of PEO in gel causes the curve milder.     

Influence of electron irradiation on properties of semi-insulating GaAs detectors

The effects of electron beam irradiation on electrical and spectrometric properties of semi-insulating (SI) GaAs detectors were studied. The electric properties were monitored by reverse and forward current–voltage characteristics. In general, a breakdown voltage decrease with the dose was observed. However, some samples showed a local increase in the breakdown voltage at doses between 5 and 10?kGy. The detector spectrometric properties (the charge collection efficiency (CCE), the energy resolution and the detection efficiency) were evaluated from measured spectra of the ²⁴¹Am radionuclide gamma source before and after electron irradiation. The CCE and energy resolution showed minor changes after irradiation. The detection efficiency noticed an initial increase (up to a dose of 5?kGy) followed by a permanent decrease. At 30?kGy, the overall degradation of detector functionality was observed with all samples.     

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

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

电子辐照改性PAN/PEO基体凝胶电解质对染料敏化太阳电池性能的提高

采用电子束（EB）对聚丙烯腈/聚氧化乙烯（PAN/PEO）凝胶电解质进行了剂量为13～260 kGy的辐照, 并对辐照改性的电解质组装的染料敏化太阳电池(DSSC)进行了性能测量。 结果表明, 改性后的DSSC的光电转化效率比改性前的高; 并且随EB辐照剂量的增加, DSSC效率先迅速增加(0～65 kGy), 然后缓慢减小(65～130 kGy)直至趋于一个平衡值(130～260 kGy)。 提升DSSC效率的最佳辐照剂量为65 kGy, 此时效率提高了约36%。 对比DSSC短路电流、 开路电压和填充因子随辐照剂量的变化, 发现DSSC效率的提高主要是由短路电流的提高引起的。 测量表明, 辐照改性后的DSSC时间稳定性得到了改善, 并且辐照剂量越高, 稳定性的改善越明显。 In this work, PAN/PEO (polyacrylonitrile/polyethylene oxide) based gel electrolyte was irradiated by electron beam (EB) with dose from 13 to 260 kGy. Then, DSSC (dye sensitized solar cell) was fabricated by the irradiated electrolyte and characterized. The results show that the efficiency of the DSSC fabricated by irradiated electrolyte is promoted comparing with DSSC fabricated by un irradiated electrolyte. And with irradiation dose increasing, the DSSC efficiency increases rapidly at first (0～65 kGy), then, drops down slowly (65～130 kGy), finally trends to a stable value (130～260 kGy). It indicates that there is an optimal irradiation dose, at which the promotion of DSSC efficiency is the highest, approximate 36%. Observed from the change of short circuit current, open circuit voltage and fill factor, short circuit current promotion by EB irradiation is found to be the main reason of DSSC performance promotion. The time stability measurement of the DSSC indicates that EB irradiation on PAN/PEO electrolyte reduces the loss of efficiency and the limiting effects become more apparent as the irradiation dose increases.     

Enhancement of Electrical and Optical Properties of Sodium Bromide Doped Carboxymethyl Cellulose Biopolymer Electrolyte Films

Abstract

Biodegradable ion conducting solid polymer electrolyte films of carboxymethyl cellulose (CMC) doped with sodium bromide (NaBr) with various weight percentages were prepared by a solution casting technique. Their structural, optical and electrical properties were studied by various experimental techniques in order to understand the impact of the sodium metal salt on the biopolymer CMC’s properties. The optical parameters namely the optical bandgap energy and the refractive index, showed a significant variable variation with the metal salt concentration. The maximum dc conductivity was found to be ～5.15?×?10^?4 S cm^?1 at room temperature for the sample with 20?wt% of NaBr content in the CMC matrix. The ionic conductivity and dielectric constant in general, increased with increase in metal salt content, affirming the increase in ion concentration. The calculated transference number showed that the conductivity was mainly due to ions. The increase in conductivity was due to an increase in degree of amorphousness of the polymer upon doping, as analyzed by their XRD spectra.     

Influence of gamma radiation on optical properties of Halloysite nanotubes incorporated polycarbonate nanocomposites

In the current research investigation, polycarbonate/hallyosite nanotubes (PC/HNTs) nanocomposite (NC) films have been successfully fabricated by solution intercalation technique using ultrasound energy in facile way which helps complete exfoliation of the HNTs in the matrix. The effect of Gamma irradiation-induced modifications of PC/HNTs NC have been studied in the dose range 200–500?kGy, irradiated with Co⁶⁰ source. The NC films have been evaluated by UV–visible spectroscopy, Fourier Transform Infrared spectroscopy, X-ray diffraction and scanning electron microscopic techniques in order to probe the effect of gamma radiation on the structural behaviors. The obtained results have been indicated that as the Gamma irradiation dosage increases from 200 to 500?kGy, phenolic group forms through scissoring of ester link of PC, which may cause PC to degrade and lose their property. At lower dosage (200?kGy), the effect is less and at higher dosage (500?kGy), the effect is significant and at 300 and 400?kGy, the effect is moderate and NC films retained their properties. The irradiation effect is most significant and effective at the higher dosage range. UV–visible spectroscopy shows a noticeable reduction in the energy band gap due to gamma irradiation.     

Variation in viscosity and ion conductivity of a polymer-salt complex exposed to gamma irradiation

We study changes in microstructure and resulting changes in the properties of PEO(1 − x)-NH₄ClO₄(x) samples where x = 0.18, when irradiated with gamma doses varying up to 50 kGy. Viscosities of aqueous solutions of the irradiated samples give an idea of the change in molecular weight and show correlation with ion conductivity. On the whole, there is a chain scission on irradiation, though there is evidence of some cross-linking at higher doses. The ion conductivity shows a strong increase for an irradiation of 35 kGy. DSC studies indicate a decrease in crystallinity with gamma dose.     

Effect of polymer blend types and gamma radiation on the physico-chemical properties of polycarbonate

Samples from polycarbonate (PC) were classified into two main groups. The first group was blended with Abietic acid (Rosin) with different compositions, while the second group was blended with ethylene-vinyl acetate (EVA) copolymer with almost the same composition. A comparative study of the effect of both Rosin and EVA concentration on the thermal stability of PC has been investigated using thermogravimetric analysis. The results show that blending with Rosin causes the dominance of degradation. Samples from PC with 20% Rosin blend were irradiated with gamma at the dose of range 20–300?kGy. The resultant effect of gamma radiation on the structural properties of the 20% Rosin/ 80%PC blend has been investigated using Fourier Transform Infrared FTIR spectroscopy. The results indicate that degradation of the polymer blend dominates, thus increases the creation of hot free radicals that leads to the formation of color centers in PC. In addition, the transmission of the 20% Rosin/80%PC samples as well as color changes was studied. The color intensity ΔE was greatly increased with increasing the gamma dose up to 300?kGy, accompanied by a significant increase in the blue color component.     

Enhanced electrochemical,structural, optical,thermal stability and ionic conductivity of (PEO/PVP) polymer blend electrolyte for electrochemical applications

This paper reports the polyethylene oxide/polyvinylpyrrolidone (PEO/PVP) blend with cobalt chloride (CoCl₂) films prepared using spin coating method on blue star glass substrate. The XRD analysis shows the decrease in the crystallinity nature of the CoCl₂ with addition of the dopant. The FT-IR analysis reveals that interaction between cobalt ions with polymer blend confirms the complexation. The maximum ionic conductivity 0.65?×?10^?4 S cm^?1 was observed for PEO (45 %)/PVP (45 %)/CoCl₂ (10 %) at 30 °C. The optical energy band gaps decreases and Urbach energy were observed increases with increasing the dopant concentration. The DSC/TGA results showed that thermal stability of films enhanced with dopant concentration. Cyclic voltammogram (CV) study shows that the electrochemical strength improves with dopant concentration. These obtained results imply that polymer blend electrolytes are suitable candidature for various applications such as electronic and optical devices like electro-chromic display, fuel cells, gas sensors and solid state batteries.     

Band gap variation in co-evaporated AgInSe2 thin films with 1.26 MeV He+ ion irradiation

Polycrystalline AgInSe₂ thin films have been prepared by co-evaporation of individual elements on glass substrate at a high temperature. The samples were subjected to the irradiation of 1.26 MeV helium ions (He⁺). Structural properties were investigated by X-ray diffraction and optical studies have been carried out from transmittance and reflectance measurements. The effect of irradiation on the structural and optical properties has been investigated for different doses of He⁺ ions. It is observed that the band gap of silver indium selenide thin films decreases gradually from 1.25 eV to 1.07 eV with irradiation dose.     

Thermal and mechanical properties of gamma-irradiated prevulcanized natural rubber latex/low nitrosamines latex blends

Thermal and mechanical properties of blended radiation prevulcanized natural rubber latex (RVNRL) and low nitrosamines latex (LNL) were studied. RVNRL was blended with LNL at various composition ratios. From the tensile test, it was found that the optimum tensile value was attained at a total blending ratio of 70% RVNRL and 30% LNL. Latex blending with optimum tensile strength was then subjected to gamma irradiation at various doses with the presence and absence of methyl methacrylate (MMA) at 10?pphr. It was found that the gamma irradiation of latex blend with the presence of MMA could help increase further the tensile value. Composition of blending at a specific ratio and gamma irradiation at a specific dose has led to a significant improvement in the mechanical properties of the latex blend. The formation of grafting in the latex blend was characterized by Fourier transform infrared spectra (FTIR) spectroscopy and differential scanning calorimetry (DSC). FTIR spectroscopy confirmed that MMA could be grafted onto blended latex effectively under appropriate irradiation conditions. Two new peaks at 1731 and 1149?cm^?1 were observed after irradiation, indicating the presence of an ester group from poly(methyl methacrylate) (PMMA), which was grafted onto rubber chains. This finding was proved by the presence of new T_g in DSC analysis. The increase in new T_g indicates the movement of grafting chains, which are tightly bound onto rubber chains.     

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

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

γ-射线辐射还原法制备金属铜掺杂MF气凝胶

采用γ射线辐射还原法,在不同总吸收剂量条件下制备了金属Cu掺杂三聚氰胺-甲醛(MF)有机气凝胶复合材料。利用X-射线衍射仪(XRD)、电感耦合等离子体吸收光谱(ICP-AES)仪和扫描电子显微镜,测试证实了辐射还原法能成功地在MF气凝胶中还原出金属Cu。扫描电子显微镜(SEM)图谱表明在100kGy和200kGy的总吸收剂量下,在MF气凝胶中还原的金属Cu粒子的粒径较小,不会形成金属团聚区,而在较高的总吸收剂量下(大于200kGy),在MF气凝胶中还原的Cu会形成金属团聚区。N2吸附测试表明,还原的金属Cu会堵塞MF气凝胶的一部分微孔和一部分介孔,从而使样品的比表面积和吸附量降低。随着总吸收剂量不断增加,经辐照后样品中金属Cu的含量也不断增加,同时还会影响还原出金属Cu的分布和形貌。     

A Comparative Study of the Dynamic-Mechanical Properties of Styrene Butadiene Rubber/Epoxidized Natural Rubber Dual Filler Nanocomposites Cured by Sulfur or Electron Beam Irradiation

The properties of (50/50?wt%) styrene butadiene rubber/epoxidized (50%) natural rubber (SBR/ENR50) blends containing nanoclay (NC, 5 or 10phr) without and with carbon black (CB 20phr) cured by sulfur or by electron beam (EB) irradiation (50 and 100kGy), were compared. A sulfur cured compound containing 35phr CB was prepared as a reference sample. Dynamic mechanical thermal analysis (DMTA) indicated that the sulfur cured sample containing 10phr NC and 20phr CB and the 100kGy irradiated sample with 5phr NC and 20phr CB had higher crosslink density, storage modulus, and tensile strength, and less loss factor and loss modulus, compared to the reference sample. Scanning electron microscopy (SEM) images of cryo- fractured surfaces confirmed the DMA and crosslink density results. We suggest a light weight 100kGy irradiated sample containing the lowest amount of NC and 20phr CB with a uniform distribution of the –C–C– bonds crosslinks, for high thermal stability applications and also for passenger cars tire treads, for its ice grip and wet skid properties especially for icy and wet roads, with improvements of 23% and 20%, respectively as compared to the reference sample.