辐照交联SBS／LDPE共混物的形状记忆效应研究

以苯乙烯-丁二烯嵌段共聚物（SBS）热塑性弹性体和低密度聚乙烯（LDPE）为主要原料,使用混炼机将SBS与LDPE按80：20的比例共混并在硫化机上模压制成SBS／LDPE共混物,利用γ射线辐照上述共混物使之交联。通过DSC分析、力学性能和形状记忆性能测试,研究了辐照交联SBS／LDPE共混物材料的结构对形状记忆性能的影响。结果表明,SBS／LDPE共混物随吸收剂量的增加,交联度增大,拉伸强度与断裂伸长率均逐渐降低;此外,适度交联的SBS／LDPE共混物呈现良好的形状记忆效应,形变回复率高于95％。     

辐射增强PP／LDPE共混体系力学性能的研究

研究了在多官能团单体－三烯丙基异腈脲酸酯存在下，ＰＰ／ＬＤＰＥ共混物的辐射效应，并用ＳＥＭ，ＤＳＣ和动态力学性能对其形态结构和相容性进行了表征。结果表明；通过添加三烯丙基异腈脲酸酯，用辐射可以强化ＰＰ／ＬＤＰＥ共混物的相间结合力，改善共混物的相容性，从而提高共混物的力学性能。     

辐射改性LDPE/EVA共混物及其超临界CO_2发泡行为的研究

用60Coγ射线辐照改性LDPE/EVA共混物,并利用超临界CO2发泡技术制得了微孔LDPE/EVA共混物泡沫。用差示扫描量热仪(DSC)、高级流变扩展系统(ARES)和扫描电镜(SEM)分别对交联LDPE/EVA共混物的熔点、结晶度、粘度以及泡沫的微孔形貌进行了表征。结果表明,辐照处理以后,LDPE/EVA共混物样品的熔点和结晶度略有降低,粘度特性得到改善,可发泡性能提高。共混物吸收剂量为50kGy时,经超临界CO2发泡在105℃和23MPa下制得的泡沫具有较好的泡孔结构。     

γ辐照对低密度聚乙烯的动态力学性能和热行为的影响

经γ辐照后所有样品的储能模量（Ｅ＇）都有所增加，从阻尼因子（ｔａｎ δ）的温度谱上所观察到β和α转变温度随辐照剂量的增加向高温方向移动。热分析结果表明，辐照后样品的热学参数Ｔｍ、△Ｈｍ和Ｔｄ随剂量的增加而降低。     

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，     

交联助剂对LLDPE/EPDM共混物辐射交联的影响

线性低密度聚乙烯（LLDPE）和三元乙丙橡胶（EPDM）的共混物可作为交联电缆的护套材料，但LLDPE的枝化度低，所需辐射交联的剂量较高。为了克服这个不足，本研究试图通过添加交联助剂的方法来降低辐射交联剂量，提高生产效率。报道了三羟甲基丙烷三丙烯酸酯（TMPTMA）、季戊四醇四丙烯酸酯（PETA）、硫磺等对LLDPE/EPDM共混物的辐射交联所产生影响的试验结果，测得了3种助剂的用量、辐射剂量对共混物的凝胶含量、力学性能及热老化性能的影响规律。结果表明，上述3种交联助剂均可不同程度地降低辐射交联的剂量，而硫碘的效果最好，且具有价格低、添加方便等优点，应为首选。     

CMOS运算放大器的质子和γ辐照效应

ＣＭＯＳ运算放大器的质子和γ辐照效应陆妩任迪远郭旗余学锋严荣良（中国科学院新疆物理研究所，乌鲁木齐，８３００１１）本文主要研究了ＬＦ７６５０ＣＯＭＳ运放电路在４、７、３０ＭｅＶ质子及６０Ｃｏγ两种不同辐射环境中的响应特性及变化规律，并通过对实验结果的...     

PET／PC共混物的辐射效应研究

研究了经溶液共混制备的聚对苯二甲酸乙二醇酯／聚碳酸酯（ＰＥＴ／ＰＣ）共混物的辐射效应。结果表明：ＰＥＴ／ＰＣ共混物在辐照过程中未发生酯交换反应和交联反应，但有降解反应发生。在研究的剂量范围内，辐照对ＰＥＴ／ＰＣ共混物中ＰＥＴ和ＰＣ的晶体形态影响不明显。     

Modification of the mesoscopic structure in neutron irradiated EPDM viewed through positron annihilation spectroscopy and dynamic mechanical analysis

This article focuses on the study of the mesoscopic structure in neutron irradiated EPDM both from experimental and theoretical points of view. In this work we reveal completely the modification of the mesostructure of the EPDM due to neutron irradiation, resolving volume fraction, size and distribution of the crystalline zones as a function of the irradiation dose. Positron annihilation spectroscopy and dynamic mechanical analysis techniques are applied and the results are discussed by means of new theoretical results for describing the interaction process between the crystals and amorphous zones in EPDM.     

Study on thermal and mechanical properties of cis- and trans-polyisoprene blends implanted by carbon ions

In the present work, elastomeric blends of cis- and trans-polyisoprene prepared by solution casting have been implanted by carbon ions (C⁶⁺) at three different fluencies with 87 MeV energy. The implanted samples were characterized through X-ray diffraction. The thermal transport and mechanical properties of implanted samples have been investigated using transient plane source and dynamic mechanical analyzer respectively. It was found that both thermal transport and mechanical properties show increasing trend up to certain fluence and beyond this fluence a decrease is observed. The variations in these properties have been discussed in terms of crosslink density and crystallinity.     

Swelling and thermal properties of porous PNIPAM/PEG hydrogels prepared by radiation polymerization

In this study,a series of porous intelligent hydrogels were synthesized by radiation exhibiting the lower critical solution temperature（LCST） and fast response involving a combination of A’-isopropyl acrylamideas monomer, polyethylene glycol（PEG） as pore-forming agent and N,N-methylene-bis-acrylamide as crosslinking agent.The hydrogels were analyzed by Fourier transform infrared spectroscopy,and the influence of radiation doses on their swelling and thermal behaviors were studied.Their surface morphologies were examined by scanning electron microscopy.The results showed that PEG molecules only acted as pore-forming agent in the cross-linked polymerization.Their swelling ratios reduced with increasing radiation doses.The LCST was around 37℃,and varied little with the radiation doses.The frozen water content of PNIPAM/PEG₆₀₀₀ hydrogel reduced with increasing the radiation dose,and was greater than that of PN1PAM hydrogel at 15 kGy.Hydrogel macropores were prepared by PEG agent,and the hydrogels without PEG had a dense surface.The porous hydrogels are expected to be applied in the field of artificial intelligence material.     

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.     

高剂量γ辐照对SEBS／PS共混物性能的影响

研究了高剂量(0～2.0 MGy)γ辐照对不同配比苯乙烯一-乙烯-丁烯-苯乙烯嵌段共聚物/聚苯乙烯(SEBS/PS)共混物(100/0～50/50)力学性能、电性能以及热稳定性能的影响.结果表明,PS的加入,可以有效改善SEBS的辐照稳定性.PS的含量越高,辐照后SEBS/PS共混物的拉伸强度、体积电阻率的下降幅度越小,介电损耗因子的上升幅度越小,热稳定性能越好.但PS的加入减少了共混物中聚烯烃相的含量,使得共混物的断裂伸长率受辐照的影响较大,特别在高剂量辐照后,PS的含量越高的共混物断裂伸长率下降越明显.     

高速高精度模数变换器的动态测试

利用数字信号处理技术，研制了一个基于ＰＣ的ＡＤＣ动态测试系统，可对高速高精度ＡＤＣ的主要动态特性进行测试。本文介绍了测试方法，系统组成和为适应高精度高速度ＡＤＣ测试采取的措施。     

Long-term properties of reduced activation ferritic/martensitic steels for fusion reactor blanket system

Thermal aging properties of reduced activation ferritic/martensitic steel F82H was researched. The aging was performed at temperature ranging from 400 °C to 650 °C up to 100,000 h. Microstructure, precipitates, tensile properties, and Charpy impact properties were carried out on aged materials. Laves phase was found at temperatures between 550 and 650 °C and M₆C type carbides were found at the temperatures between 500 and 600 °C over 10,000 h. These precipitates caused degradation in toughness, especially at temperatures ranging from 550 °C to 650 °C. Tensile properties do not have serious aging effect, except for 650 °C, which caused large softening even after 10,000 h. Increase of precipitates also causes some degradation in ductility, but it is not critical. Large increase in ductile-to-brittle transition temperature was observed in the 650 °C aging. It was caused by the large Laves phase precipitation at grain boundary. Laves precipitates at grain boundary also degrades the upper-shelf energy of the aged materials. These aging test results indicate F82H can be used up to 30,000 h at 550 °C.     

一种Zr基非晶/晶体复合型核材料的力学性能与耐腐蚀性能的研究

采用Zr65Cu35和Nb双靶直流共溅射方法,通过调节Nb靶的溅射功率,制备了不同Nb含量的Zr Cu Nb非晶薄膜。分别使用能谱仪、X射线衍射仪、高分辨透射电子显微镜观察Zr Cu Nb非晶薄膜的成分与结构,最终选择具有优异非晶形成能力的Zr53Cu38Nb9成分溅射到纯Zr基片上,以制备锆基非晶复合材料。研究测试Zr53Cu38Nb9非晶复合材料的力学性能与耐腐蚀性能。结果表明:与纯Zr基片相比,复合材料在弹性阶段力学性能无明显差异;而在塑性变形阶段,由于非晶薄膜与纯Zr基片的变形与断裂机制不同,该复合材料具有更好的拉伸塑性,其表现为非晶膜厚为280 nm、640 nm和960 nm的复合材料的最大拉伸塑性形变较纯Zr基片分别提高了2.72%、5.22%、4.27%;在耐腐蚀性能方面,非晶膜厚为640 nm的复合材料与纯Zr基片相比,具有较小的自腐蚀电流密度icorr、较正的腐蚀电位Ecorr以及较大的容抗弧半径,表现出更优异的耐腐蚀能力。因此,该新型Zr基复合材料在核材料领域具有潜在的应用。