2－烷基蒽醌引发环氧丙烯酸酯光固化行为的研究

研究了在没有其它活化剂存在条件下，采用２－烷基蒽醌直接引发环氧丙烯酸酯体系的光交联反应。应用光谱方法和重量法测定了反应体系在光固化过程中双键含量、光交联密度、凝胶转化率和固化膜硬度的变化情况。实验结果表明，２－烷基蒽醌直接引发环氧丙烯酸酯类的光固化反应，具有很好的引发效率，可以和安息香双甲醚与流杂蒽酮等光引发剂相比拟，并具有价格便宜、光固化可在空气条件下操作等优点，另外对反应体系的引发剂浓度、组分配比的影响以及对不同类型环氧丙烯酸酯反应体系的引发效果均进行了讨论。     

2—烷基蒽醌引发环氧丙烯酸酯光固化行为的研究

研究了在没有其它活化剂存在条件下，采用２－烷基蒽醌直接引发环氧丙烯酸酯体系的光交联反应，应用光谱方法和重量法测定了反应体系在光固化过程双键含量，光交联密度，凝胶转化率和固化膜硬度的变化情况，实验结果表明，２－烷基蒽醌直接引发环氧丙烯酸酯类的光固化反应，具有很好的引发效率，可以和安息香双甲醚与硫杂蒽酮等光引发剂相比似，并具有价格便宜，光固化可在空气条件下操作等优点，另外对反应体系的引发剂浓度，组分配     

含苯基脂环型环氧有机硅预聚体的制备及其光固化

以高含氢硅油(甲基氢硅油)为原料,通过与苯乙烯、4-乙烯基环氧环己烷在Lamoreaux催化剂作用下的硅氢加成反应,制备了具有苯环侧链的脂环族环氧有机硅预聚体(Ep-Ph-SiO)。利用1H-NMR确定了芳环、环氧和硅氢嵌段的比例关系,得到了Ep-Ph-SiO的平均组成;同时测定了Ep-Ph-SiO的折射率。以4-(苯硫基)苯基二苯基硫鎓六氟磷酸盐为光引发剂,考察了Ep-Ph-SiO在高压汞灯辐射下的阳离子光固化。研究发现,所制备的含苯基脂环族环氧有机硅预聚体能有效地发生阳离子光固化,光固化活性高于常用的缩水甘油型环氧预聚体;随着苯环含量的增加,树脂折射率提高。     

有机硅改性纳米凝胶降低光聚合体系的收缩应力

采用硫醇为链转移剂,以甲基丙烯酸酯改性硅油,二脲烷二甲基丙烯酸酯和甲基丙烯酸异冰片酯为主要原料,合成了一种可聚合型有机硅改性纳米凝胶。研究了纳米凝胶的加入量对三乙二醇二甲基丙烯酸酯光聚合体系的聚合动力学、收缩应力、弯曲强度、弯曲模量及热稳定性的影响。结果表明,有机硅的添加,能够使三乙二醇二甲基丙烯酸酯光固化体系延迟凝胶,有效降低收缩应力。有机硅的加入也能提高聚合物的热稳定性,并且其添加质量分数在不大于20%时不影响聚合物的机械性能。     

聚氨酯改性丙烯酸环氧单酯的光-热固化性能

合成了聚氨酯改性丙烯酸环氧单酯,树脂分子结构中同时具有光固化基团(双键)和热固化基团(环氧基团).用FTIR表征了光-热固化过程特征吸收峰的变化.研究了不同的稀释剂、热固化剂对光固化和光—热混杂固化的凝胶率、吸水率、力学性能和热性能的影响,结果表明:光固化膜的凝胶率低于89％,而光—热混杂固化膜的凝胶率在97％左右.在...     

阳离子光引发剂[Cp-Fe-diphenylether]+PF6-的合成和光引发性能的研究

制备了一种具有芳茂铁盐结构的新型阳离子光引发剂[环戊二烯基-铁-二苯醚]六氟磷酸盐([Cp-Fe-diphenylether]^ PF6^-),并研究了其作为阳离子光引发剂在高压汞灯下引发环氧预聚体的光引发活性。发现其由d-d跃迁产生的394nm和462nm的吸收峰同I-261([环戊二烯基-铁-异丙苯]六氟磷酸盐)相比红移约10nm,且摩尔吸光系数ε有所提高;以高压汞灯为辐射光源,对脂环族环氧ERL4221和TDE85及脂肪族环氧树脂E44均有良好的光引发活性;与增感剂过氧化苯甲酰(BPO)混合使用,其光引发活性高于碘鎓盐SR-1012;光照后仍具有较强的聚合活性。     

聚丙烯粉料固相光接枝丙烯酸的研究

为了提高聚丙烯(PP)的亲水性和染色性,以二苯甲酮(BP)为光引发剂、使用固相光接枝反应装置,采用固相紫外光接枝法在PP粒料表面接枝丙烯酸(AA)单体,并研究了单体含量、引发剂用量、辐照时间和溶胀时间对接枝率的影响规律,以及PP接枝前后力学性能的变化。结果表明,AA用量为1mL、引发剂用量为0.15g、辐照时间为30min、溶胀时间为12h时的接枝率最高。接枝率为5.2%左右,上染率为43.4%时,接枝PP的拉伸强度降了1.37MPa,但断裂伸长率从358.3%增加到396.3%,说明丙烯酸适度接枝对力学性能影响不大。     

双酚A型环氧树脂阳离子紫外光固化动力学的研究

以双酚A型环氧树脂为主体成分构成紫外阳离子光固化体系,用常规的最低光固化速度测试方法和实时傅立叶变换红外光谱法研究了各种条件对体系光固化速度的影响。结果表明,光引发剂的种类和浓度可以有效地改变光固化速度,环氧稀释剂会大幅度降低光固化速度,而羟基化合物的加入只是轻微降低光固化速度。在三元体系中,其光固化速度并不是几种作用的简单叠加,而是更加类似于羟基化合物的性质。使得通过调节合适的组分构成和配合,能够获得具有合适光固化速度的紫外阳离子光固化配方,从而会大大扩展其应用的技术领域。     

邻羟基环己基甲基丙烯酸酯的合成及光聚合性质研究

以环氧环己烷和甲基丙烯酸为原料,通过环氧开环反应,合成了邻羟基环己基甲基丙烯酸酯(HCMA)单体.采用实时红外光谱技术(RTIR)研究了单体结构、光照强度、不同引发剂及引发剂浓度对光聚合动力学的影响.合成的单体与甲基丙烯酸羟乙酯(HEMA)混合,采用光聚合方法制备水凝胶,通过动态力学热分析(DMA)测定对比了共聚水凝胶与均聚水凝胶的力学性能.结果表明,增大光强和引发剂浓度可提高体系双键转化率;含HCMA共聚单体的水凝胶的储能模量和损耗模量高于均聚水凝胶.     

光引发剂对紫外光固化胶粘剂性能的影响

制备了以IR651和IR1700为引发剂的紫外光(UV)固化胶粘剂，研究其感光性能和粘接性能。在曝光30s后，以IR1700为引发体系的UV固化胶粘剂的剪切强度可达8．3MPa，而引发体系为IR651的剪切强度仅为0．6MPa。比较了两种光引发剂时的感光性能，IR1700体系的感度值为2．85mJ/cm^2，而IR651的为4．03mJ/cm^2。经深度固化研究表明，IR1700具有深度光固化的优异性能。     

低能电子辐照对环氧树脂性能的影响

为了研究低能电子辐照对环氧树脂的体积电阻率、邵氏硬度、拉伸强度和官能团结构的影响,本文在电子辐照能量为30 keV,注量率1×10¹¹ cm^-2•s^-1,总注量为1.6×10¹⁴ cm^-2,真空度10^-6 Pa条件下,结合国家标准对辐照前、后环氧树脂材料的机械性能和结构进行表征。结果表明,辐照后环氧树脂材料的体积电阻率、邵氏硬度、拉伸强度等宏观物理性能均有下降。傅里叶红外光谱图显示环氧树脂主要官能团强度降低,产生的•H、•OH等自由基与聚合物分子上的羟基与氢结合。研究结果对环氧树脂材料在辐射环境中的使用具有重要意义。     

Enhancement of dispersion and adhesion of B4C particles in epoxy resin using direct ultrasonic excitation

Enhancement of the mechanical properties of the B₄C/epoxy composites, which is used as a neutron shield for spent nuclear fuel cask, was achieved by direct ultrasonic dispersion of the B₄C particles in the hardener using an immersed horn, while those prepared without direct ultrasonic dispersion showed insufficient adhesion as well as some agglomerates in the epoxy resin. Degrees of agglomeration and adhesion were analyzed by means of the SEM images and the FTIR peaks belong to C-C stretching mode of the hardener ring, which was lowered and flattened by van der Waals interaction between the B₄C particles and the hardener ring substituent. The tensile strength of the B₄C/epoxy composites prepared by direct ultrasonic dispersion was maintained (or increased) compared to that for the neat epoxy matrix, while those prepared without ultrasonic dispersion were degraded significantly. Consequently, direct ultrasonic dispersion process developed in this investigation could achieve uniform dispersion as well as strong adhesion of the B₄C particles in/with the epoxy matrix enhancing the material properties without any chemical treatment resulting unwanted impurities.     

Gamma irradiation effects on cyanate ester/epoxy insulation materials for superconducting magnets

Cyanate ester/epoxy resin was used as a cryogenic-grade polymer matrix and glass fiber reinforced polymer (GFRP) composite was manufactured. The processing properties of matrix resin in terms of the isothermal viscosity at 45 °C were investigated. The specimens were exposed with gamma irradiation of 1 MGy, 5 MGy and 10 MGy, respectively. The effect of gamma irradiation on thermal properties and structure of cyanate ester/epoxy matrix was investigated. The interlaminar shear strength (ILSS) of the composites before and after irradiation were investigated at room temperature, 77 K and 4.2 K. Results showed that cyanate ester/epoxy system had a low viscosity and a long pot life at 45 °C. The glass transition temperature of the matrix resin decreased with the increasing irradiation dose. Moreover, the ILSS of GFRP composite slightly increases after irradiation and toughening mechanism was also discussed.     

Improvement of carbon fiber surface properties using electron beam irradiation

Carbon fiber-reinforced advance composites have been used for structural applications,mainly on account of their mechanical properties.The main factor for a good mechanical performance of carbon fiber-reinforced com- posite is the interfacial interaction between its components,which are carbon fiber and polymeric matrix.The aim of this study is to improve the surface properties of the carbon fiber using ionizing radiation from an electron beam to obtain better adhesion properties in the resultant composite.EB radiation was applied on the carbon fiber itself before preparing test specimens for the mechanical tests.Experimental results showed that EB irradiation improved the ten- sile strength of carbon fiber samples.The maximum value in tensile strength was reached using doses of about 250 kGy.After breakage,the morphology aspect of the tensile specimens prepared with irradiated and non-irradiated car- bon fibers were evaluated.SEM micrographs showed modifications on the carbon fiber surface.     

接枝型耐紫外线老化乙烯-乙酸乙烯酯共聚物的制备及其性能研究

摘要将4-丙烯氧基,2-羟基二苯甲酮（AHB）作为紫外光吸收剂与乙烯-乙酸乙烯酯共聚物（EVA）以不同比例共混后通过平板硫化机压成1mIn厚的的片材,空气氛围中,以4．4×10^5kGy·h^-1的剂量率对其进行辐照,将AHB以化学键方式接枝固定在EVA中。采用GB／T1040．2006方法考察共混片材的机械性能,FT-IR光谱表征共混膜中AHB的存在,紫外光谱考察紫外线吸收性能,光学显微镜观察片材拉断后的截面形貌。结果表明,随AHB的含量从0phr增加至2phr,材料的断裂伸长率从586％上升至772％;同时抗张强度从32．1MPa下降至22．4MPa;添加1份（每100份聚合物）紫外吸收剂的EVA抗紫外老化性能显著优于未添加的样品。     

Effects of neutron irradiation on polymer matrix composites at 5 K and at room temperature: II. Degradation of mechanical properties

Neutron irradiation with a low flux of accompanying γ-rays in the Intense Pulsed Neutron Source was carried out at 5 K and at room temperature on four kinds of polymer matrix composites (filler: E-glass or carbon fiber cloth; matrix: epoxy or polyimide resin). The specimen irradiated at 5 K was warmed up to room temperature before the mechanical test was performed at 77 K. The Young's modulus of these composites scarcely decreases even when a total neutron fluence is 3.0 × 10¹⁸n/cm² (2.1 × 10¹⁸n/cm² for E > 0.1 MeV) for the 5 K irradiation and 1.6 × 10¹⁹n/cm² (8.0 f 10¹⁸ n/cm² for E > 0.1 MeV) for the room-temperature irradiation. The ultimate strength, however, decreases significantly at this neutron fluence for all the composites except the carbon/epoxy composite whose initial strength is comparatively low. Comparison of this result with that obtained for ⁶⁰Co γ-ray irradiation demonstrates that the radiation sensitivity of the glass/epoxy and glass/polyimide composites is 1.8–2.6 times higher towards neutrons than γ-rays. As to the irradiation temperature of 5 K and room temperature, no significant influence on the degradation efficiency of the composite strength is observed under the present conditions of mechanical test.     

新型纤维增强环氧树脂基复合材料研制及其中子屏蔽性能研究

核技术应用产业的迅速发展,对中子辐射屏蔽材料的种类、服役环境、结构性能提出更多、更高要求。针对发展功能/结构一体化中子屏蔽材料需求,研制了一种新型玻璃纤维/B₄C/环氧树脂复合材料。力学测试与中子屏蔽实验发现,该复合材料中子屏蔽性能良好,5 cm厚样品屏蔽后中子透射率仅19.6%;材料具有较高强度与模量,性能优于铅硼聚乙烯。增大材料B₄C含量对提升材料中子屏蔽性能作用显著,但同时材料强度、模量有一定减小。综合考虑该材料的中子屏蔽性能、承受载荷以及耐高温特性,其在反应堆、加速器及中子源等核设施外围防护材料,尤其是乏燃料贮存格架材料用途上具有较大应用潜力。     

Study of electron beam curing process using epoxy resin system

Polymeric matrix composite (PMC) has been used in engineering applications instead of metal in the last few years, due to its corrosion resistance and excellent relation between tensile strength/density and elastic modulus/density. However, PMC materials cured by thermal process require high temperature and are time-consuming. The electron beam (EB) curing technology allows its use at room temperature and reduced curing times, and this is one of the main advantages over thermal technology. The aim of this work is to investigate electron beam curable epoxy formulations to use in filament winding processes to produce composite material with similar or better properties than thermal curable composites. The study has been made with commercial epoxy resins and cationic initiators. The epoxy resin samples were irradiated for few minutes with total dose of 150 kGy. The glass transition temperatures (T_g) were determined by dynamic mechanical analyzer (DMA) and the result was 137 °C. The thermal process was carried out in a furnace following three steps: 4 h at 90 °C, increasing temperature from 90 °C to 130 °C during 4 h and 12 h at 130 °C. The total process time was 20 h. The T_g of this sample was 102 °C.     

Influence of various catalysts on the radiation resistance and the mechanical properties of cyanate ester/epoxy insulation systems

Fiber reinforced composites impregnated with mixtures of various cyanate ester and epoxy resins demonstrated their excellent performance at the ITER design fluence and beyond. The insulation systems consist of a wrapped R-glass/Kapton reinforcement, vacuum impregnated with a cyanate ester/epoxy blend. For the fabrication of the insulation a long pot-life of the resin is of great importance, which is mainly determined by the amount and the composition of the catalyst needed for curing the resin. However, the catalyst, which amounts to 1–2% of the resin, may also affect the mechanical properties as well as the radiation hardness of the material. In order to investigate these effects, two different composites were fabricated using a Mn- and a Co-catalyst, respectively.The mechanical properties are characterized prior to and after irradiation to a fast neutron fluence of 1 × 10²² m⁻² (E > 0.1 MeV) in tension and interlaminar shear at 77 K.     

Oil palm empty fruit bunch (OPEFB) fiber reinforced PVC/ENR blend-electron beam irradiation

The effect of irradiation on the tensile properties of oil palm empty fruit bunch (OPEFB) fiber reinforced poly(vinyl chloride)/epoxidized natural rubber (PVC/ENR) blends were studied. The composites were prepared by mixing the fiber and the PVC/ENR blend using HAAKE Rheomixer at 150 °C. The composites were then irradiated by using a 3.0 MeV electron beam machine at doses ranging from 0 to 100 kGy in air and room temperature. The tensile strength, Young’s modulus, elongation at break and gel fraction of the composites were measured. Comparative studies were also made by using poly(methyl acrylate) grafted OPEFB fiber in the similar blend system. An increase in tensile strength, Young’s modulus and gel fraction, with a concurrent reduction in the elongation at break (Eb) of the PVC/ENR/OPEFB composites were observed upon electron beam irradiation. Studies revealed that grafting of the OPEFB fiber with methyl acrylate did not cause appreciable effect to the tensile properties and gel fraction of the composites upon irradiation. The morphology of fractured surfaces of the composites, examined by a scanning electron microscope showed an improvement in the adhesion between the fiber and the matrix was achieved upon grafting of the fiber with methyl acrylate.