Effect of electron beam radiation on the polypropylene/polyethylene blends: Radiation stabilization of polypropylene

The effect of incorporation of polyethylene in the polypropylene matrix, on the radiation sensitivity of polypropylene, has been investigated. The changes in the properties such as tensile strength, elongation at break, Shore D hardness, density and melt flow index were monitored as function of polyethylene content and electron beam radiation dose. A correlation between the mechanical properties and morphology of the irradiated polymeric blends has been observed, which has been explained on the basis of Fourier-transform infrared spectroscopy, scanning electron microscope and X-ray diffraction studies. Improvement in the mechanical properties of the polypropylene, irradiated to an optimum electron beam dose, could be achieved by blending it with polyethylene >20%. The optimum radiation dose was found to be dependent on blend composition and morphology, however, an absorbed dose of 250 kGy found to be effective enough to ensure good mechanical properties of the polypropylene/polyethylene blends.     

电子辐照PVA/CMC共混水凝胶的成胶研究

本试验利用电子辐照PVA/CMC共混水凝胶,通过外观透明度、凝胶分数、溶胀度和红外光谱分析,研究了样品中结构的变化与外观透明度、凝胶分数和溶胀度的关系,以及辐照剂量对样品中结构和性能的影响.结果表明,不同比例的PVA与相同比例的CMC组成的共混水凝胶,经电子辐照后呈现不同的宏观特性.辐照样品萃取后得到的凝胶比萃取前的混合凝胶拥有更强的吸水性,表明辐照PVA/CMC共混凝胶形成了网状结构凝胶.几种竞争反应导致不同辐照剂量下混合凝胶中凝胶含量随PVA含量的变化变得复杂.辐照后样品的红外光谱分析显示,辐照使凝胶中部分仲醇中C上链接的H原子被取代而转变为叔醇,从而产生交联.     

Effect of electron beam irradiation sterilization on the biomedical poly (octene-co-ethylene)/polypropylene films

The effect of electron beam irradiation with the dose ranging from 15 to 40 kGy on poly (octene-co-ethylene) (POE)/polypropylene (PP) films was investigated. Wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), yellowness index testing and mechanical performance measurement were applied to characterize the films. It demonstrated that crystalline structure exhibited little change, and degree of crystallinity slightly change under the irradiation treatment. Irradiation brought about oxidation of the films, forming hydroxyl groups of the peroxides and carbonyl groups. Tensile properties become worse as irradiation dose increased. Electron beam irradiation with the dose of 15-40 kGy has little effect on crystalline performance and a little influence for the POE/PP films, indicating a good irradiation resistance.     

Studies on mechanical, thermal and morphological properties of irradiated recycled polyamide and waste rubber powder blends

The aim of this article was to show the effect of gamma irradiation on mechanical and thermal properties of recycled polyamide (rPA) copolymer blended with different content of waste rubber powder (WRP). In order to study the structural modifications of prepared blends have been subjected to irradiation doses up to 200 kGy were applied to all samples. Non-irradiated blends were used as control samples. Mechanical properties, namely, tensile strength (TS), elastic modulus, elongation at break and hardness have been followed up as a function of irradiation dose and degree of loading with rubber content. Furthermore, the influence of radiation dose in the thermal parameters, melting temperature, heat of fusion, ΔH_f of the recycled PA and its blend with waste rubber powder (WRP) was also investigated.     

电子束辐照制备Pd/TiO2光催化薄膜

用电子束辐照浸泡在浓度分别为1×10-5、1×10-4、1×10-3、1×10-2和1×10-1mol/L的PdCl2溶液中的TiO2薄膜,在TiO2薄膜表面形成Pd纳米颗粒.通过X射线衍射(X-ray diffractometry,XRD)、场发射扫描电镜(Field emission scanning electron microscope,FESEM)、X射线光电子能谱(X-ray photoelectron spectroscopy,XPS)和紫外可见(Ultraviolet visible,UV-Vis)吸收光谱对辐照后的Pd/TiO2薄膜进行表征.分析表明,TiO2薄膜表面上沉积了直径20-50 nm的颗粒,为面心立方结晶的金属Pd;Pd/TiO2薄膜的UV-Vis光谱吸收边向可见光方向发生了偏移.用甲基橙作为光催化降解反应物,研究了Pd/TiO2薄膜分别在紫外光、可见光作用下的光催化降解效率.结果表明,Pd/TiO2薄膜的光催化能力显著地提高,在紫外光、可见光作用下的光催化效率分别提高了2.25倍和3.4倍.     

Stabilization of polypropylene, polypropylene blends with poly (styrene-b-(ethylene-co-butylene)-b-styrene) under irradiation: A comparative investigation

The aim of this paper is to investigate the stabilization of polypropylene in the poly (styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS)/polypropylene (PP) blends under irradiation with respect to PP. The PP films, SEBS/PP films were subjected to electron beam irradiation and characterized by wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), gel permeation chromatography (GPC), and dynamic mechanical thermal analysis (DMTA). It demonstrated that upon irradiation, the molecular weight of PP had a pronounced decrease due to the major chain scission, and the minor chain cross-linking or chain branching occurred at the higher irradiation dose. Stabilization of PP was improved in the presence of SEBS, exhibiting an enhanced irradiation resistance.     

电子束辐照对多酚氧化酶活性及结构的影响

应用圆二色谱及SDS-PAGE技术分析电子束辐照对多酚氧化酶(Polyphenol oxidase,PPO)活性及结构的影响。结果发现:电子束辐照可在一定程度上降低PPO酶活性;圆二色谱分析发现电子束辐照处理后,PPO酶蛋白质二级结构相对含量发生改变,但a螺旋、b折叠和b转角总含量在吸收剂量4.83 kGy时总量变化不大,当吸收剂量4.83 kGy时,随着剂量的增加含量不断下降,无规则卷曲呈上升趋势。SDS-PAGE电泳实验结果表明,辐照处理下PPO酶同时发生交联和降解反应。上述结果提示电子束辐照对PPO酶活性有一定的抑制作用。     

Monte Carlo study of molecular weight distribution changes induced by degradation of ion beam irradiated polymers

In this work we study a polymeric material that degrades upon irradiation due to the energy inhomogeneously deposited by heavy ion beams. Ion beam irradiation of polymers generates rather different effects than those induced by “classical” low ionizing particles such as electrons or gamma rays. This is due to the high electronic stopping power and the inhomogeneous distribution of deposited energy. This energy is transferred to the material within a small volume along the ion path forming the so called “nuclear track” or “latent track”. The track size primarily depends on the ion velocity, and it is determined by the secondary electrons (delta rays) generated along the ion trajectory. By means of Monte Carlo simulations we first obtained equilibrated polymer configurations using a coarse-grained model, and then investigated the spatially inhomogeneous chain scission process due to the passage of the ions. The number average molecular weight, weight average molecular weight and the polydispersity were calculated as a function of track radius, scission probability within the ion track and irradiation fluence. Finally we compared our results with a numerical implementation of a model for random homogeneous degradation.     

电子束注入PMMA空间电荷分布的Monte-Carlo模拟与实验验证

精确控制和测量电子束注入样品后电荷量以及电荷的沉积分布,对于进行高压电力电缆材料的击穿以及航空器受到高能宇宙射线破坏的研究有着非常重要的意义。本工作结合空间电荷对固体电介质材料击穿影响的研究课题,利用Monte-Carlo方法模拟计算了电子束注入聚甲基丙烯酸甲脂(PMMA)样品中电荷的沉积分布,并通过激光感应压力波法(LIPP)对电子束注入后的PMMA进行测量;实验验证计算结果,吻合较好,为以后实验参数的设计提供了重要依据。     

GaN基LED高能电子束流辐照效应研究

使用高能电子辐照对GaN基蓝光发光二极管(Light Emitting Diode,LED)光电学性能的影响进行研究。高能电子束流分别对不同组别的LED样品进行辐照实验,并通过自动测控系统对辐照过程中LED的电流、光强、光谱峰值波长进行全程测控。随后,在室温无辐照环境下对上述不同组别的LED样品进行跟踪对比测试研究。实验结果表明,高能辐照对LED的改性有明显效果,具体表现在工作电流和发光功率变化时受辐照影响的稳定性有所改善,光谱峰值波长出现蓝移。同时,GaN基LED在辐照过程中是否通电对LED的光电学性能有显著影响。     

电子束辐照唐菖蒲球茎对 M1代花粉的影响初探

为了探讨电子束对唐菖蒲诱变育种的可行性和不同剂量的电子束对花粉性状的影响,用能量为3MeV的不同剂量电子束辐照唐菖蒲"超级"球茎,对其M1代的花粉进行了研究.花粉活力的检测表明电子束辐照处理后的M1代花粉活力比对照略有下降,但小剂量辐照对花粉活力的影响并不明显,随着剂量的增加,辐照对花粉活力的抑制作用逐渐达到显著水平;扫描电镜观察发现,随着辐照剂量的增大,M1代花粉的孢粉学特征与对照差异逐渐明显,并且出现了多种变异形式;通过对M1代花粉酯酶同工酶的分析.结果表明,酯酶同工酶与对照相比发生了明显的变化,其中剂量在120Gy以下的酶带与对照相同,但酶活性较对照变弱,剂量为160Gy和200Gy时出现了一条新的酶带并且有两条酶带消失,剂量为240Gy时酶谱出现了一条特异酶带同时有一条酶带消失,并且剂量大于160Gy的酶活性与对照以及其他剂量相比也略有不同.由此表明,电子束辐照对植株能产生明显的影响,通过对花粉的一系列分析,能够较好地反映辐照对植株的诱变情况.     

电子辐照SiGe HBT和Si BJT的直流特性分析

研究了1MeV不同剂量电子辐照前后SiGe异质结晶体管(HBT)的直流特性,并与Si双极晶体管(BJT)进行了比较。结果表明辐照后SiGe HBT的IB基本不变,Ic和β都下降;随电子辐照剂量的增加,Ic和β都减小。对si BJT而言,IB和Ic与在相同辐照剂量辐照后的SiGe HBT相比都增大很多,β下降幅度也很大。这说明SiGe HBT具有比Si BJT更好的抗辐照性能。对电子辐照后器件电学性能的变化机制进行了初步分析。     

尼龙66/紫外辐照线性低密度聚乙烯共混物的力学性能

通过紫外辐照实现了高密度聚乙烯(HDPE)的官能化，改善了HDPE复合材料的性能。本工作采用傅立叶红外(FT-IR)、X射线光电子能谱(XPS)、凝胶、熔融指数和水接触角测试等研究了紫外辐照对线性低密度聚乙烯(LLDPE)化学结构和性能的影响。紫外辐照后，在LLDPE的分子链上引入了C=O、C-O和C(=O)O等含氧基团，其含量随辐照时间延长而增加。凝胶分析结果表明，紫外辐照过程中，LLDPE产生凝胶，     

Sustained transdermal release of diltiazem hydrochloride through electron beam irradiated different PVA hydrogel membranes

Extremely fast release of diltiazem hydrochloride (water soluble, anti anginal drug used to treat chest pain) together with its faster erosion has been the primary problem in conventional oral therapy. It has been addressed in this paper by encapsulating the drug in electron beam irradiated various poly (vinyl alcohol) hydrogel membranes and delivering it through transdermal route. Results show excellent control over the release of diltiazem hydrochloride through these membranes subject to their physico-mechanicals.     

电子束辐射预硫化天然橡胶/丁苯橡胶并用体系的研究

以天然橡胶,丁苯橡胶(Natural rubber/styrene butadiene rubber,NR/SBR)并用体系为基材,采用电子束辐照技术对其进行辐射预硫化,研究了不同吸收剂量下,材料交联度、硫化速度及格林强度的变化趋势,并评价了电子束辐射预硫化对材料最终力学性能的影响.结果表明:NR/SBR并用体系的交联度和格林强度随吸收剂量的增加而提高,热硫化速度基本不受吸收剂量的影响,可实现删SBR并用体系的辐射预硫化;辐射预硫化与未辐射预硫化的NR/SBR相比,完全硫化后材料的力学性能相差不大.     

Visible light active TiO2 films prepared by electron beam deposition of noble metals

TiO₂ films prepared by sol-gel method were modified by electron beam deposition of noble metals (Pt, Pd, and Ag). Effects of noble metals on the chemical and surface characteristics of the films were studied using XPS, TEM and UV-Vis spectroscopy techniques. Photocatalytic activity of modified TiO₂ films was evaluated by studying the degradation of methyl orange dye solution under visible light UV irradiation. The result of TEM reveals that most of the surface area of TiO₂ is covered by tiny particles of noble metals with diameter less than 1 nm. Broad red shift of UV-Visible absorption band of modified photocatalysts was observed. The catalytic degradation of methyl orange in aqueous solutions under visible light illumination demonstrates a significant enhancement of photocatalytic activity of these films compared with the un-loaded films. The photocatalytic efficiency of modified TiO₂ films by this method is affected by the concentration of impregnating solution.     

环氧树脂分子量对电子束辐射固化效果的影响

研究了分子量对于环氧树脂电子束辐射固化行为的影响规律。环氧树脂体系的辐射反应速率随分子量增加而下降,在低辐射剂量下,高分子量树脂的固化度和固化层厚度较小,提高辐射剂量,分子量的影响减弱。对于辐射固化程度较高的样品,其玻璃化温度(Tg)和贮能模量(E’)主要受固化度控制。电子束辐射固化的环氧树脂进行热处理后,样品的玻璃化温度和高温E’均有所提高,低分子量树脂的热处理效果更为明显。     

Dose intercomparison studies for 60Co gamma-ray and electron beam irradiation in the year 2002

1 Introduction With the rapid development of radiation process- ing by electron beam irradiation in China, it is more Ever since 1962, alanine/EPR dosimetry system and more needed to establish a transfer dosimetryhas been used to measure the absorbed dose.[1] Its ad- system with high accuracy to assure the quality of thevantages over othe…     

低能电子束循环辐射硫化天然橡胶乳液

应用250keV低能电子束循环辐射硫化二丙烯酸壬酯（1,9-nonanedilo diacrylate，NDDA）敏化的天然橡胶乳液，探讨了影响低能电子束循环辐射硫化天然橡胶乳液的因素。结果表明，提高电子束束流，可缩短辐射硫化时间；40％的天然橡胶乳液更适合低能电子束的辐射硫化；适当提高循环乳液的重量有利于辐射硫化乳液的质量控制。     

电子束辐照接枝对棉织物抗皱/拒水拒油性能的影响

利用MG-6600型拒水拒油剂以及柠檬酸抗皱剂,以轧烘焙、电子束辐照接枝、等离子体预处理-电子束辐照接枝三种工艺对棉织物进行后整理。傅里叶红外光谱(FTIR)证明拒水拒油剂与柠檬酸已成功接枝于棉纤维上;扫描电子显微镜(SEM)分析表明经三种工艺整理后的棉织物表面均有一层覆盖物,且经等离子预处理后的织物表面出现纵向条纹。通过测量棉织物折皱回复角(WRA)、对水的接触角(WCA)、对油(正十六烷)的接触角(OCA)大小来表征织物性能的变化。结果表明,在等离子体预处理-电子束辐照接枝工艺条件下,棉织物的抗皱、拒水、拒油性能达到最优,其WRA为185.9°,WCA为158.9°,OCA为129.1°,断裂强力、白度值均能满足服用要求,同时棉织物的耐水洗性能大大提高。