^60Co辐照对PTFE表面结构和表面能的影响

为了改善氟聚合物加工性和二次加工性,研究了PTFE聚合物的加工技术。以不同剂量辐照PTFE,PTFE粉末辐照后表面晶相没有发生变化。模压辐照的PTFE,其密实性较好,表面光滑。同时,辐照PTFE后表面有大量的极性亲水基团出现,使表面极性分量增加;而色散分量变化较小。辐照产生的表面极性基团减小了由于不同模压产生的表面所引起的接触角变化。     

弹性体的电子束加工

电子束辐照是一种离子化的辐照，它可以给有机物带来深刻的变化。它影响到原子的电子层但不会对原子核产生任何显著的影响。通过电子束对聚合物进行的辐照交联是一个连续的过程，它能在不到一秒的极短的时间内完成一系列的反应。电子束辐照加工已在聚合物的交联和改性方面成功地应用了几十年。它主要优点是反应速度快、清洁以及非常精确的过程控制。本文目的是针对主要应用在橡胶制品生产中的电子束技术，以及与之相关的化学、设备、过程、应用及最新的进展进行综述。     

二次辐照对交联聚乙烯结构和性能的影响及其应用

研究了辐照对高密度聚乙烯(HDPE)、低密度聚乙烯(LDPE)、线型低密度聚乙烯(LLDPE)、乙烯-乙酸乙烯酯共聚物(EVA)及其共混物性能的影响。将辐照交联后的聚合物经扩张定型后再次辐照,考察了二次辐照对交联结构的影响,并利用二次辐照法制备了一种新型热收缩套管产品。结果表明:随着辐照剂量的增加,样品的凝胶含量增大,拉伸强度先增大后减小,而断裂伸长率则逐渐降低;二次辐照后,样品的形变回复率随着辐照剂量的增加显著降低;所制备的热收缩套管两端收缩率大、中间部分收缩率小,实现了同一制品不同部位收缩倍率的可控性,具有良好的应用前景。     

快重离子辐照改性介电聚合物的结构演变与储能性能提升

由于薄膜电容器具有低极性,绝缘阻抗高,频率响应宽等优点,具有旁路、去耦、滤波和储能的功能,广泛应用于通信、电子、航空航天、医疗设备、新能源等行业。近年来,由于行业的发展,低介电损耗、高击穿场强与高能量密度的新型介电材料的研发变得愈发重要。采用氙重离子束对聚(偏二氟乙烯–六氟丙烯)进行辐照改性,系统地研究了辐照注量对材料微观结构、介电性能和储能性能的影响。结果表明,¹²⁹Xe²⁷⁺快重离子辐照促进了优势相变与表面交联结构形成,提高了材料的储能效率与击穿场强。同时,辐照断键提高了材料的介电常数,增强了有效极化。多种效应协同作用下,成功制备了高击穿场强(540 MV/m)、高放电能量密度(16.3 J/cm³)的辐照改性聚合物材料,为促进聚合物介质电容器的发展提供了理论与实验依据。     

辐照交联在高分子材料耐热改性中的应用进展

辐照交联是一种能耗低、环境友好型的用于聚合物改性的技术手段,能够改善高分子材料的耐热性.介绍了辐照交联在高分子材料耐热改性领域中的应用,回顾了辐照交联改性高分子材料耐热性能方面的研究,对辐照交联技术现存的问题进行分析并提出了相应的改进方法.     

微波辐照技术在聚合物合成方面的研究及发展

综述了微波辐照技术在聚合物合成方面的研究状况,介绍了微波技术在本体聚合、乳液和溶液聚合及功能高分子合成方面的应用。在聚合物微波固化方面,重点介绍了环氧树脂及其复合材料的微波固化,简要地介绍了其它聚合物的微波固化。最后探讨了微波技术在未来的发展趋势。     

具有低可浸出氟离子的经辐照的氟聚合物物品

正涉及已用至少5 kGy辐照过的氟聚合物物品,其中这些得到的物品具有低水平的可浸出的或可引出的氟离子。来自该经辐照的物品的低氟离子迁移是由于在该氟聚合物组合物中存在低水平的金属盐或金属氧化物。该发明对于其中氟聚合物层与生物或药物流体相接触的、并且经受辐照灭菌的氟聚合物物品是特别有用的。(CN103597021A)     

含苯并咪唑杂环结构聚酰亚胺纤维辐照接枝研究

为解决含芳杂环结构的聚酰亚胺(PI)纤维的接枝问题，采用共辐照法对具有不同芳杂环结构的PI纤维进行辐照改性，通过红外光谱、X射线电子能谱、吸水率分析等探究辐照接枝处理对含芳杂环结构的PI纤维结构与性能的影响。研究发现：含苯并咪唑结构的PI纤维表现出可辐照接枝性，其辐照接枝率可达5.7%；而不含杂环结构的PI纤维则难以辐照接枝；红外光谱与X射线电子能谱分析表明，丙烯酸单体接枝位点为PI纤维分子中的苯并咪唑杂环；经辐照改性后，所得改性PI纤维的亲水性及染料吸附能力得到有效改善，表现出在复合材料及吸附等领域巨大的应用潜力。     

共辐照法制备羟丙基淀粉的影响因素北大核心

通过γ射线共辐照法制备了羟丙基淀粉,利用分光光度计、傅里叶变换红外光谱仪、扫描电子显微镜、X射线衍射仪测定了摩尔取代度、化学结构、微观形貌及结晶结构,并讨论了辐照剂量、反应物配比、催化剂及浸泡处理对摩尔取代度的影响,以及辐照接枝反应对羟丙基淀粉红外特征吸收、晶体结构和微观形貌的影响。结果表明:共辐照可以得到较低摩尔取代度的羟丙基淀粉,辐照剂量100 k Gy以下是辐照接枝效率较高的区间,而氢氧化钠的加入则可以有效提高摩尔取代度。     

用改性纳米PTFE粉末填充的EPDM性能之研究

聚四氟乙烯具有化学不活泼性,其不易与其他聚合物兼容,但经辐照后其表面经过改性,使其与不饱和橡胶基团形成偶合反应,增加了兼容性和分散性、可提高硫化胶的力学性能。     

添加剂类型与超声辐照间的相关性研究

选用大同和神木煤制备水煤浆,考察了超声辐照与添加剂类型间的相关性,实验结果表明,采用不同类型的添加剂,超声辐照后煤浆各性质的变化规律大致相同,即辐照能显著改善各煤 流变特性以及大幅度提高煤浆的静态稳定性,添加剂加入量为１％时,辐地 煤浆表现粘度增另,在相同的辐照条件下,煤浆表观粘度的增加与添加剂的分散相有关,添加剂的分散性越强,其煤浆的表观粘度增另越是有离子添加剂比非离子添加剂更有利于辐照对煤浆     

低能紫外辐照聚丙烯的结构与性能

用低能紫外辐照聚丙烯,在聚丙烯分子链上引入含氧极性基团,改善聚丙烯与填料或其他工程塑料共混的相容性。通过光电子能谱（ＥＳＣＡ）、偏光显微镜、熔体流动速率（ＭＦＲ）仪、接触角和动态粘弹谱（ＤＭＴＡ）仪、毛细管流变仪等近代分析测试,研究了紫外辐照聚丙烯的结构、形态与性能。随紫外辐照时间的增加,聚丙烯的熔体流动速率增加,接触角下降。经过紫外辐照,聚丙烯的结晶形态发生了变化。对比紫外辐照聚丙烯及与绢英粉共     

电子束辐射对PTFE/GF摩擦磨损和压缩性能的影响

考察电子束辐射对玻璃纤维增强聚四氟乙烯(PTFE/GF)摩擦磨损性能和压缩性能的影响。结果表明,经电子束辐射后,PTFE/GF的耐磨性能和压缩性能均显著提高。当电子束辐射剂量为300 kGy时,PTFE/GF的耐磨性能提高了1.83倍,压缩弹性模量提高了0.8倍。分析认为,由电子束辐射引发的PTFE结晶度的提高使得PTFE/GF具有良好的耐磨性能和压缩性能。     

Irradiation effects on polycaprolactone

The structure and some physical properties of γ-irradiated polycaprolactone (PCL), a semi-crystalline linear saturated polyester, were studied as function of the irradiation dose level. The critical dose level for gel formation is 26 Mrad and above this irradiation dose the number of scission events is similar to the number of crosslinking events. G.p.c. results show that the initial rather narrow molecular weight distribution gradually widens with increasing dose in the pre-gelation region. A significant difference between first and second d.s.c. scans of irradiated PCL is shown and explained. Scission and crosslinking reactions associated with the irradiation process occur preferentially in the non-ordered regions. Small irradiation doses, 2–5 Mrad, are shown to have a dramatic effect on the tensile elongation at break by converting ductile PCL samples into brittle materials.     

硫系红外玻璃材料耐辐射性能研究进展

硫系玻璃在航空航天、核子反应监测与探测等领域有着广阔的发展前景和重要的应用价值,是目前光电子技术领域中最受关注的材料之一。本文对近年来国内外关于硫系玻璃耐辐照性能研究的相关情况进行了综合评述,重点阐述了硫系玻璃在γ射线辐照环境中的损伤机理,同时对影响耐辐照性能的因素进行分析,提出了增强硫系玻璃耐辐照性能的可行途径,最后展望了未来该领域的研究方向和发展前景。     

Nanoscale surface roughening of mulberry silk by monochromatic VUV excimer lamp

Surface treatment of mulberry silk was carried out using a VUV excimer lamp (172 nm). The changes occurring in morphology and physical properties of silk were studied. The nanopores created on the surface of treated samples were quantitatively analyzed using a high resolution scanning electron microscope. The physical and chemical changes taking place in silk fabric on irradiation were studied through measurement of wetting and wicking time, weight loss, crystallinity, and strength. Effect of irradiation time and distance from the lamp on these properties was also studied. Results show that wettability and wickability of silk improved significantly on exposure before stabilizing at 5 min irradiation time while the weight loss continued to increase. The effect of irradiation was negligible when the distance of the sample from the lamp became >15 mm. The effect of irradiation on tensile strength was found to be insignificant. Presence of moisture in silk hindered the effect of irradiation. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 4102–4106, 2007     

Role of lateral and radial irradiations on efficient microwave processing of food cylinders

A detailed theoretical analysis has been carried out to assess the role of lateral and radial irradiations on microwave heating of 2D cylinders for beef and oil samples. The lateral irradiation may represent the sample incident at one direction and the radial irradiation refers to sample exposed to uniform microwave intensities at all directions. For both lateral and radial irradiations, the effective microwave incidence from the source is assumed to be identical. A preliminary analysis on microwave heating of samples has been shown via average power within a sample vs sample radius for beef and oil samples. The samples with smaller radius are found to have larger average power with radial irradiation for both beef and oil samples. The hot spot formation within a sample is found to be a strong function of lateral/radial irradiation for various food dielectrics. The radial irradiation is found to be not favorable especially for large oil samples where the hot spot occurs at the center resulting in larger thermal gradient that contrasts earlier works which established that the radial irradiation minimizes the thermal gradient irrespective of sample size. The present work provides guideline on heating policy based on either lateral or radial irradiation depending on sample size and food dielectric properties.     

Radiation crosslinking of poly(vinyl chloride)/epoxidized natural rubber blend: effect of lead stabilization of the poly(vinyl chloride) phase

The irradiation crosslinking of 50/50 poly(vinyl chloride)/epoxidized natural rubber blend was investigated in the presence of 1–5 parts per hundred resin (phr) tribasic lead sulfate (TBLS) with blends prepared at various mixing temperatures. The blends were irradiated using a 3.0 MeV electron accelerator at 0, 100 and 200 kGy irradiation doses. Changes in tensile strength, elongation at break and stress‐strain curves of the blends with the increase TBLS content and blending temperatures were observed before and after irradiation. The results on the tensile properties revealed the inhibition of the irradiation‐induced crosslinking by the TBLS although it stabilizes the blend against thermal and irradiation‐induced degradation. The Fourier transform infrared spectroscopy studies further confirmed these observations. Control on the thermal degradation of the blend during blending found to be crucial in achieving maximum enhancement in blend properties upon irradiation. Evidence from dynamic mechanical analysis was also used to support this contention. Addition of 2 phr TBLS and blending at 150 °C found to be adequate in order to achieve the best enhancement in blend properties through irradiation‐induced crosslinking. © 2001 Society of Chemical Industry     

纤维素辐照改性及其应用

辐照技术利用电离辐射诱发物理化学反应(例如交联、聚合、接枝、降解等)对材料进行加工或改性,与常规加工方法相比,具有节能、无环境污染等特点。将辐照技术应用于纤维素改性过程近年已成为非动力核技术应用领域研究的热点之一。本工作对目前纤维素的辐照技术及其基本反应机理进行了概述,其中包括纤维素膜材料、纤维素水凝胶、纤维素微晶/纳米材料,并对纤维素辐照改性过程的辐照环境,包括溶剂、敏化剂、温度、辐照剂量、环境氛围、结晶度等进行了总结。     

Thermal,mechanical, and corrosion resistance properties of vinyl ester/clay nanocomposites for the matrix of carbon fiber‐reinforced composites exposed to electron beam

Vinyl ester/clay nanocomposites with 1, 3, and 5% nanoclay contents were prepared. X‐ray diffractography patterns and Scanning Electron micrographs showed that nanocomposites with the exfoliated structure were formed. Thermogravimetric analysis, water absorption test, and Tafel polarization method, respectively, revealed the improvements in thermal resistance, water barrier properties, and corrosion resistance properties of the samples with an increase in the amount of the incorporated nanoclay. Tensile tests showed that nanoclay also enhanced the mechanical properties of the polymer, so that the tensile strength of the samples with 5% nanoclay was more than 3 times higher than tensile strength of pure vinyl ester samples. Overall, the best properties were observed for the samples containing 5% nanoclay. Pure vinyl ester and nanocomposite with 5% nanoclay content were exposed to the electron beam radiation and their mechanical properties improved up to 500 kGy irradiation dose. Finally, pure vinyl ester and vinyl ester/nanoclay (5%) matrixes were reinforced with carbon fiber and the effect of electron beam irradiation on their mechanical properties was examined. The tensile strength and the modulus of the samples initially increased after exposure to the radiation doses up to 500 kGy and then a decrease was observed as the irradiation dose rose to 1000 kGy. Moreover, nanoclay moderated the effect of the irradiation. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42393.