轮胎胶脱硫共混物增韧聚丙烯的影响因素

在轮胎胶粉与热塑性弹性体(POE)共混物的熔融挤出过程中添加有机醇类化合物作为脱硫反应促进剂,研究双螺杆挤出机的螺杆转速和挤出反应温度对轮胎胶脱硫共混物的凝胶含量、溶胶分子链结构及增韧PP材料力学性能的影响.实验结果表明:随着双螺杆挤出机螺杆转速的增加或挤出反应温度的升高,轮胎胶粉颗粒所受到的机械剪切应力作用或热能作用均明显增强,强烈的剪切应力和热能可引发轮胎胶中交联网络的断裂、降解或解交联反应发生,引起脱硫共混物中凝胶含量明显下降、凝胶粒子尺寸明显减小以及与PP材料相容性明显改善.添加有机醇-1化合物作为脱硫反应促进剂时,有利于脱硫反应的进行,有利于脱硫产物中双键的保护,并引起脱硫共混物凝胶合量进一步下降、凝胶颗粒尺寸进一步减小和增韧PP材料力学性能进一步提高.在240℃条件下添加有机醇-1化舍物进行脱硫反应,当脱硫反应螺杆转速由400 r/min增加至1200 r/min时,所得脱硫共混物增韧PP材料(PP/DGTR/POE=70/24/6)的缺口冲击强度可由17.4kJ/m2提高至34.4 kJ/m2,并且引起此共混材料拉伸强度、断裂伸长率、弯曲模量及熔体指数的明显增大.     

电子束辐照再生丁基橡胶

介绍了电子束辐照再生丁基橡胶的技术原理,试验研究的情况,加工工艺流程,技术特点,以及推广前景,市场预测,财务评价等。     

低能电子束辐射固化涂料的研究

以低能电子束处理多种配方的涂料,研究了辐射剂量、加速电压和氧气浓度对涂料固化性能的影响。结果表明：氧气浓度高于一定程度时将会导致涂层固化困难,辐射剂量对涂膜性能有着直接的影响,较高的加速电压有利于较厚涂层的固化。并对EB固化与UV固化后的涂膜性能进行了对比测试,表明EB固化涂料在性能上存在明显的优势。     

Influence of Codiluent Reactives in Electron Beam Cured Films

Two urethane diacrylates—one aromatic, M1100; and the other aliphatic, M1200—have been used to prepare elastic films under electron beam (EB) irradiation. Two monofunctional diluents are used; N-vinyl pyrrolidone (NVP) is used as the reactive diluent monomer, and the second one, called the codiluent, is chosen from a series of acrylated monomers with T_g values lower than that of NVP. Pencil hardness; gel content; swelling ratio in acetone; and mechanical properties such as yield strength, break strength, elongation, and Young's modulus of the cured films are determined. Among the various codiluents used, vinyl acetate (VAc), cyclohexyl acrylate (CHA), and tertiary butyl acrylate (t-BA) played a significant role in inducing improved Theological properties in the cured films.     

Electron Beam Irradiation of EVA/ENR Blend

The effect of irradiation on a 50/50 ethylene vinyl acetate/epoxidized natural rubber blend was studied. The 50/50 ethylene vinyl acetate/epoxidized natural rubber blend was prepared by mixing in a Brabender Plasticoder at 120°C. The blend was then irradiated by using a 3.0 MeV electron beam machine at doses ranging from 20 to 100 kGy in air and room temperature. The dynamic mechanical properties, tensile properties, hardness, and gel fractions of the blends were measured. It was found that the tensile strength, modulus, and hardness of the blend increased with irradiation with a concomitant decline in elongation at break. Results on the gel fraction revealed that under the irradiation conditions employed, the EVA/ENR blend crosslinked by electron beam irradiation. The addition of TMPTA and Surlyn ionomer was found to be effective in increasing the degree of crosslinking.     

电子束辐照预硫化技术及其应用研究

阐述电子束辐照预硫化技术的设备结构和反应机理以及辐照剂量均匀性评价方法,探讨电子束辐照预硫化技术在半钢子午线轮胎胎体帘布加工中的应用。结果表明:辐照剂量对胎体帘布胶、帘布及其纤维原丝、轮胎性能有一定的影响;电子束辐照预硫化技术在轮胎生产中应用前景广阔,可以在优化工艺、提高生产效率和提升轮胎产品品质等方面发挥重要作用。近年来,国内大型轮胎企业在半钢子午线轮胎胎体帘布压延生产线新建或改造项目中基本配备了电子束辐照预硫化设备,但是目前亟待解决其故障率较高的问题。     

电子束辐照技术在环境保护中的应用

电子束辐照降解技术作为辐照技术的一个分支,近年来获得了快速发展,在环境保护中的应用日益广泛。概述了电子束辐照降解技术在处理废气、废水以及固体废弃物等方面的研究应用,指出了环境保护中电子束辐照技术所存在的问题,并展望了其应用前景。     

Ozonation and Electron Beam Irradiation of Dyes Mixture

In this study, the effects of ozone and electron beam radiation on color removal of dyes mixture were studied. According to the obtained results, the COD data denote that a first-irradiation process is a better one and the absorbency data denote that ozonation after irradiation will result in higher values of decolorization. Therefore, it can be said that a process that first applies an electron beam and then uses ozonation is better than the reverse process. Using a new approach for interpretation of the experimental decolorization results, it has been shown that the calculated dye removal percentages based on ozone consumption are near to experimental decolorization results.     

Degradation by Electron Beam Irradiation of Some Composites Based on Natural Rubber Reinforced with Mineral and Organic Fillers

Composites based on natural rubber reinforced with mineral (precipitated silica and chalk) and organic (sawdust and hemp) fillers in amount of 50 phr were obtained by peroxide cross-linking in the presence of trimethylolpropane trimethacrylate and irradiated by electron beam in the dose range of 150 and 450 kGy with the purpose of degradation. The composites mechanical characteristics, gel fraction, cross-linking degree, water uptake and weight loss in water and toluene were evaluated by specific analysis. The changes in structure and morphology were also studied by Fourier Transform Infrared Spectroscopy and Scanning Electron Microscopy. Based on the results obtained in the structural analysis, possible mechanisms specific to degradation are proposed. The increasing of irradiation dose to 450 kGy produced larger agglomerated structures, cracks and micro voids on the surface, as a result of the degradation process. This is consistent with that the increasing of irradiation dose to 450 kGy leads to a decrease in crosslinking and gel fraction but also drastic changes in mechanical properties specific to the composites’ degradation processes. The irradiation of composites reinforced with organic fillers lead to the formation of specific degradation compounds of both natural rubber and cellulose (aldehydes, ketones, carboxylic acids, compounds with small macromolecules). In the case of the composites reinforced with mineral fillers the degradation can occur by the cleavage of hydrogen bonds formed between precipitated silica or chalk particles and polymeric matrix also.     

Lipoxygenase and Tocopherol Profiling of Soybean Genotypes Exposed to Electron Beam Irradiation

Electron beam (EB)-irradiation is increasingly being preferred to radioactive-based gamma irradiation in overcoming the constraints that affect the quality of food material. Soybean seeds of 3 soybean genotypes were exposed to 4 doses viz. 4.8, 9.2, 15.3 and 21.2 kGy of EB-irradiation and assessed for the changes in the contents of lipoxygenase isozymes and tocopherol isomers. Densitometry of protein profile revealed decreasing intensity of lipoxygenase with increasing EB dose. All the 3 lipoxygenase isozymes viz. lipoxygenase-1, -2 and -3 registered significant (P < 0.05) increasing reduction with increasing dose; though genotypic variation was noted for the magnitude of reduction at the same dose. Concomitantly, all the 3 genotypes exhibited significant (P < 0.05) decline in α-, γ- and δ-isomers of tocopherol. δ-Tocopherol was the most sensitive to EB-irradiation. EB dose, which caused minimum and maximum decline in total tocopherol content, was genotype-dependent. Decline in vitamin E activity corresponding to the dose, which induced maximum reduction for total lipoxygenase also varied in 3 genotypes. The study showed the usefulness of EB for significant inactivation of off-flavor generating lipoxygenases in soybean, with a non-significant effect on oil content and varied retention of tocopherol isomers and vitamin E activity depending upon genotype.     

电子束辐照交联PVC/EVA共混物的研究

以丙烯酸酯类多官能团不饱和单体为交联敏化剂，采用电子束对聚氯乙烯(PVC)与乙烯—酸酸乙烯共聚物(EVA)的共混物进行辐照交联。研究了VA质量分数、交联敏化剂种类及用量、辐照剂量、EVA用量对共混物凝胶质量分数、力学性能以及热延伸性能的影响。结果表明：EVA共聚物能促进PVC的辐照交联，增加共混体系的凝胶质量分数，改善其力学及热延伸性能；EVA共聚物中VA质量分数增大，共混体系的凝胶质量分数增大，力学及热延伸性能改善更明显。     

Improved Adhesion of Butyl Mastic Using Electron Beam Irradiation

Abstract

Butyl mastic is used in a number of industrial areas and in particular in the production of adhesives. The performance of this material can be improved by using ionizing radiation. In this work we showed that the shear forces in butyl mastic were modified when the material was exposed to radiation, and as a consequence the adhesion strength was increased. This was done by comparing the shear forces of butyl mastic before and after the exposure to ionizing radiation. The result was an increase of 440% of the average shear strength between the sealant and the substrate after the irradiation. This work can be considered as an important contribution to the field of butyl mastic. sealants and adhesives.     

电子束辐照灭菌用PP材料改性研究

为了解决聚丙烯（PP）在电子束辐照后变黄的问题,选取助剂Irganox 1010、Irganox 1076、Tinuvin 770、Chimassorb 944进行对比探究,进行黄变指数、差式扫描量热仪、热失重测试及拉伸强度测试。结论表明,在加入0.5份Tinuvin 770时,样品的黄变指数最小;加入抗氧剂、光稳定剂再辐照后,结晶度提高,热失重外延起始温度降低,拉伸强度和断裂伸长率降低,冲击强度增加,冲击断面粗糙,表现为韧性断裂。     

电子束固化双酚A环氧丙烯酸酯／聚丙烯酸酯体系的研究

本文以接枝型聚丙烯酸酯为主体同时加入双酚Ａ环氧丙烯酸酯,经过电子辐照同化后,形成的聚合物具有一定的剥离强度,持粘性和初粘性。     

Mechanical Properties of Electron Beam Cured Monomer and Monomer/Liquid Crystal Films

This article reports on mechanical properties of electron beam cured tripropylene glycol diacrylate (TPGDA) and propoxylated glycerol triacrylate (GPTA) films. This study has been motivated by the need to have direct access to those properties for analyzing the thermo‐mechanical behavior and electro‐optical properties of polymer dispersed liquid crystal systems in general, and systems made either of TPGDA or GPTA and low molecular weight liquid crystals in particular. Representative examples of these systems are considered in this work. The effects of the degree of crosslinking on the mechanical strength of the polymer network are analyzed by considering different doses of the electron beam irradiation. As the radiation dose increases, the mechanical strength of the film is enhanced. Addition of a small amount of liquid crystals leads to remarkable plasticizing effects.

Young modulus and rubbery state modulus as a function of EB dose for cured TPGDA films. The filled symbols represent the Young modulus and the open symbols represent the rubbery state modulus. Circles are for pure TPGDA and squares are for TPGDA/E7 mixture with 15 wt.‐% E7.     

Properties of Polyisoprene-Based Pressure Sensitive Adhesives Crosslinked by Electron Beam Irradiation

Many pressure sensitive adhesives are based on partially-crosslinked blends of an elastomer and a tackifying resin. In this work, a model pressure sensitive adhesive system was studied based on anionically-polymerized polyisoprenes. The effects of the initial molecular weight of the polyisoprene and the degree of crosslinking on the adhesive properties were investigated. The adhesives were crosslinked by electron beam irradiation to achieve particular levels of gel content. The dependence of gel content on dose and molecular weight is in good agreement with statistical crosslinking theory. The molecular weight of the soluble fraction was always dominated by that of the initial elastomer. With regard to creep resistance, it was observed that high gel content could compensate for low molecular weight. This was not true of the peel behavior.     

电子辐射对渗透性材料上书写墨水信息记录的影响

本文介绍电子辐射对不同墨水书写信息的影响。2001年10月当发现炭疽病毒感染邮寄的信件时,美国政府开始利用电子辐射杀死邮件上的病毒,并在全国推广这项技术。可是过了一段时间发现,这项技术对某些邮寄物品是有害的。数据表明电子辐射可能对邮品上存在的时间特征有损害,尤其是邮寄通过常规船运的美术和历史资料,时间特征是非常重要的。     

电子束辐射对铜绿微囊藻生理活动的影响

采用电子束辐射方法对铜绿微囊藻生长进行抑制和去除,通过呼吸速率及主要酶活性的变化,研究不同辐射剂量对藻细胞生理活动的影响.结果表明:电子束辐射使铜绿微囊藻受到严重迫害,呼吸速率及抗氧化酶活性在逆境胁迫条件下先增加后降低.3～5 kGy辐射迫害较为严重:藻细胞在辐射胁迫下引起抗氧化酶系统活性降低,体内活性氧产生和清除间的...     

电子束辐射对铜绿微囊藻生长过程的影响研究

在辐射剂量分别为1、2、3、4、5kGy的情况下,研究电子束辐射对铜绿微囊藻生长过程及繁殖规律的影响。结果表明:1kGy的辐射剂量能减缓铜绿微囊藻的正常生长,2~5kGy有明显的灭活效果。实验结束时,对照组和1kGy辐射组光密度上升1.082和0.407;2~5kGy下降分别为0.533、0.731、0.889和0.946。铜绿微囊藻叶绿素a含量的变化规律与光密度变化规律相似。电子束辐射降低藻液的pH值,铜绿微囊藻通过光合作用和生理调节使pH值升高并逐渐稳定下来。电子束辐射使藻液的电导率增加,并通过对藻细胞的破坏使电导率保持增加。电子束辐射使铜绿微囊藻的细胞结构发生明显变化。电子束辐射首先减少细胞外的糖类物质,进而破坏类囊体结构,使光合作用受阻。     

Preparation and Electron Beam Irradiation of PVC/ENR/CNTs Nanocomposites

Poly (vinyl chloride), PVC/epoxidized natural rubber blend, ENR/carbon nanotubes, CNTs nanocomposites were prepared using melt intercalation and solution blending methods. In both preparation methods PVC: ENR: CNTs ratios were fixed at 50:50:2, while the 50/50 PVC/ENR blend without the addition of CNTs was used as control. The PVC/ENR/CNTs nanocomposites were exposed to electron beam (EB) irradiation at doses ranging from 0–200 kGy. The effects of two different preparation methods on the tensile properties, gel fraction and morphology of the PVC/ENR/CNTs nanocomposites were studied. Prior to EB irradiation, the addition of 2 phr of CNTs caused a drop in the tensile strength (Ts) of the 50/50 PVC/ENR blend, implying poor distribution of CNTs in the PVC/ENR blend matrix. However upon EB irradiation, the nanocomposites prepared by the melt blending method exhibited higher values of Ts as compared to the neat PVC/ENR blend due to occurrence of radiation-induced cross-linking in the PVC/ENR blend matrix. Transmission electron microscopy (TEM) images proved that a better dispersion of CNTs in PVC/ENR blend matrix can be achieved by melt intercalation compared to solution blending and the dispersion of CNTs was improved by irradiation. Scanning electron microscopy (SEM) results showed a distinct failure surface with formation of rough structure for the irradiated nanocomposites, which explains the higher values of tensile properties compared to the non-irradiated nanocomposites.