光固体丙烯酸化聚氨酯的合成及力学性能

以２，４－ＴＤＩ、丙烯酸β－羟丙酯、聚乙二醇（不同分子量）、正一元醇为原料，合成了８种新的光固化丙烯酸化氨基甲酸酯。用元素分析、ＩＲ、ＵＶ、蒸气压渗透法，对它们进行了表征和鉴定，测试了它们光固化后的力学性能与曝光时间的关系。结果表明，随固化时间增长，玻璃化温度Ｔ、模量Ｅ、断裂强度都随之而增大；到一定固化时间后，Ｔ、Ｅ、断裂强度保持不变，断裂伸长率在某一固化；时间出现一最大值。     

环氧聚硅氧烷丙烯酸酯的合成及其光固化的研究

本文以环氧聚硅氧烷〈简称ＥＰＳ〉与丙烯酸进行加成反应，合成了一种游离基光固化的有机硅预聚物－－环氧聚硅氧烷丙烯酸酯〈简称ＡＥＰＳ〉。该予聚物既具有热固性硅橡胶的特性，又具备丙烯酸酯树脂快速光固化的优点，是一种比较理想的光敏聚合材料。它已在新发展的ＵＶ－固化光纤涂料中应用。     

丙烯酸环氧单酯的合成及光-热固化性能

以环氧树脂和丙烯酸为原料,合成了既可以光固化也可以热固化的丙烯酸环氧单酯,用FT-IR表征了合成产物以及光-热固化过程特征吸收峰的变化.研究了不同的稀释剂对光固化和光-热联合固化的凝胶率、吸水率、力学性能和热性能的影响,测试结果表明,光固化膜凝胶率低,柔韧性好,光-热固化以后断裂强度增大.     

游离基光固化有机聚硅氧烷AEPS的研究

本文以环氧聚硅氧烷（简称ＥＰＳ）与丙烯酸进行加成反应，合成了一种游离基光固化的有机硅预聚物─—环氧聚硅氧烷丙烯酸酯（简称ＡＥＰＳ）。该预聚物既具有热固性硅橡胶的特性，又具备丙烯酸酯树脂快速光固化的优点，是一种比较理想的光敏聚合材料。它已在新发展的ＵＶ－固化光纤维涂料中获得应用。     

含硫高折光紫外光固化树脂的合成及其固化性能研究

合成了含硫高折光紫外光固化树脂,采用红外光谱(FT-IR)、核磁和质谱表征了树脂结构。配制了一系列紫外光固化体系,用FT-IR表征了固化过程特征吸收峰的变化。测试了紫外光固化膜的凝胶率、吸水率、力学性能、体积收缩率、折光率和表面水接触角。结果表明:在相同稀释剂条件下,与双酚A环氧丙烯酸双酯光固化膜相比,高折光紫外光固化树脂(二苯硫醚环氧丙烯酸双酯含量65%)固化后凝胶率可以达到97.2%,体积收缩率在9.71%,断裂强度为26.72MPa,断裂伸长率5.23%,水接触角为55.72°,与双酚A环氧丙烯酸双酯体系相当,但其折光率为1.5572,明显高于双酚A环氧丙烯酸双酯体系的1.3069。     

光固化胶粘剂的研制

采用环氧丙烯酸树脂制备光固化胶粘剂,研究了胶粘剂各组分含量、引发剂配比、引发剂含量对固化时间和粘接强度的影响,得到了一种具有优良光固化性能和粘接强度的光固化胶粘剂.     

阳离子光固化有机聚硅氧烷EPS的研究

本文通过硅氢加成合成了一种有机硅的阳离子光敏预聚物－环氧聚硅氧烷（简称ＥＰＳ），并以合成的二苯基碘氟硼酸盐（ＤＰＩＦＢ）及氟锑酸盐（ＤＰＩＦＳ）作光敏聚合引发剂，对其阳离子光固化进行了研究，结果表明，ＥＰＳ光固化组成物既具有通常热固性硅橡胶低温性能好，耐湿、耐热、耐环境老化的特性，又具有环氧树脂快速固化的优点，可作为新一代ＵＶ固化光纤涂料应用。对两种盐引发ＥＰＳ光固化的速度进行比较的结果表明，氟锑酸盐的活性明显高于氟硼酸盐，再加入安息醚作促进剂，可使ＥＰＳ获得最快的固化速度。     

系列紫外光-热混杂固化树脂的合成及其性能

合成了一系列同时具有光固化基团(双键)和热固化基团(环氧)的聚氨酯改性丙烯酸环氧单酯。用红外光谱(FT-IR)表征了固化过程特征吸收峰的变化,测试了柔性链段对聚氨酯改性丙烯酸环氧单酯光-热混杂固化膜的凝胶率、吸水率、力学性能、体积收缩率和热性能的影响。结果表明,在相同稀释剂条件下,与丙烯酸环氧单酯光-热固化膜相比,聚氨酯改性丙烯酸环氧单酯光-热固化膜的凝胶率可达97%以上,断裂强度有所下降,但断裂伸长率由4.6%提高到19.5%,体积收缩率由6.07%下降到4.22%,光-热固化膜的热分解温度超过了240℃。     

光固化快速成型中光敏树脂固化机理研究

合成了一种适于光固化快速成型的环氧丙烯酸光敏树脂,探讨了该光敏树脂的紫外光固化机理,用SEM表征了树脂体系固化后的微观结构,用红外光谱(FTIR)对树脂体系固化过程进行了分析。研究结果表明:光敏树脂经紫外光固化后,呈交联的、不规则体型网络结构;树脂在光固化过程中,光引发剂的含量在一定数值范围内与光敏树脂中C=C双键的转化率成正比。     

渗透型丙烯酸树脂的合成与表征

报道了渗透型丙烯酸树脂的合成过程与结构表征，探讨了合成反应中影响产率的因素。对所合成丙烯酸树脂的粘度、玻璃化温度（Ｔｇ）等物理性能与Ｅｕｄｒａｇｉｔ ＲＳ进行了对比研究，证明该合成路线是可行的。     

Mechanism of radiation-induced degradation in mechanical properties of polymer matrix composites

Four kinds of polymer matrix composites (filler, E-glass or carbon fibre cloth; matrix, epoxy or polyimide resin) and pure epoxy and polyimide resins were irradiated with ⁶⁰Co -rays or 2 MeV electrons at room temperature. Mechanical tests were then carried out at 77 K and at room temperature. Following irradiation, the Young's (tensile) modulus of these composites and pure resins remains practically unchanged even at 170 MGy for both test temperatures. The ultimate strength, however, decreases appreciably with increasing dose. The dose dependence of the composite strength depends not only on the combination of fibre and matrix in the composite but also on the test temperature. A relationship is found between the composite ultimate strain and the matrix ultimate strain, thus indicating that the dose dependence of the composite strength is virtually determined by a change in the matrix ultimate strain due to irradiation. Based on this finding, we propose a mechanism of radiation-induced degradation of a polymer matrix composite in order to explain the dose dependence of the composite strength measured at 77 K and at room temperature.     

The influence of electron beam irradiation on the shear bond strength of glass-reinforced frameworks and veneer composites

The bond between glass fibre framework and veneer composite can be achieved by silane coupling agents or by monomers that penetrate into a polymer network. However, it has been clinically demonstrated that his bond can fail. This study investigated whether electron beam irradiation improved the bond strength of fibre-frameworks and veneer composite with and without additional coupling agents.     

含光敏剂的高支化碱溶性感光聚合物的合成及性能

以1,2,4-苯三四酸酐,环氧氯丙烷和光敏剂1173合成了分子内带有光敏单元的高支化碱溶性聚酯,聚合反应转化率在1h内可达90%以上,以甲基丙烯酸缩水甘油酯与高支化聚酯反应制得分子内带有光敏单元的高支化碱溶性光固化树脂,树脂的热转变温度在160～210℃,在碱水溶液中溶解性好,无需外加光敏剂在紫外光照射下便可固化、交联,光固化的反差γ可达到7.30。     

填充物、胶膜和Z-pin对复合材料T型接头强度影响对比

为提高复合材料T型接头结构的拉伸强度,对接头中胶膜属性、圆弧区填充物属性和Z-pin增强三种结构参数对T型接头强度的影响进行了研究。设计了两种不同胶膜属性、两种不同填充材料和有无Z-pin的同尺寸试验件,完成拉伸试验,测得极限位移和极限拉伸强度,并进行了对比分析,同时研究了不同T型接头的损伤演化过程。结果表明：J299胶膜复合材料T型接头的极限位移和极限载荷相比于J116B胶膜分别提高了57.8%和64.7%;ZXC195增强芯复合材料T型接头的极限位移和极限载荷相比于单向带材料分别提高了51.7%和30.3%;Z-pin钉对复合材料T型接头的极限位移和极限载荷分别提高了190.8%和31.9%。三种结构参数均只影响接头的极限载荷和极限位移的大小,接头的整体刚度没有改变。胶膜属性对接头极限载荷的提高影响最大,而Z-pin对接头的极限位移提高影响最大。     

ZrW_(2)O_(8)-Cf/E51低/负热膨胀复合材料制备及超声时间对其热膨胀和力学性能的影响EI北大核心

为了制备低膨胀、高强、轻质复合材料,采用模压法制备了ZrW_(2)O_(8)-Cf/E51复合材料,并研究了超声时间对其微观组织、热膨胀行为和极限抗拉强度的影响。结果表明:在制备过程中颗粒团聚后容易受到纤维单丝阻挡并在纤维束表面聚集。在20 min之内,延长超声时间会减少ZrW_(2)O_(8)颗粒团聚。随着颗粒团聚的减少,复合材料断口会由平面状、无纤维拔出变为台阶状、有纤维拔出。在碳纤维和ZrW_(2)O_(8)颗粒的综合作用下,ZrW_(2)O_(8)-Cf/E51复合材料在热膨胀过程中膨胀量dL/L0会出现增大、减小和缓慢上升三个阶段,平均热膨胀系数也会出现相应的三个阶段。超声时间从5 min延长到20 min,ZrW_(2)O_(8)-Cf/E51复合材料的平均热膨胀系数降低了约130%,极限抗拉强度提高了约8%。     

Studies on certain wood-plastic-composites prepared by gamma irradiation

Wood-plastic-composites have been prepared using locally available soft wood and commercial monomers by vacuum impregnation of monomer in wood and subsequent polymerization by gamma irradiation. The irradiation was performed by means of a⁶⁰Co source of strength 50,000 Ci at 0·2 Mrad/h. The radiation dosage required for maximum conversion of monomer into polymer was less than 2 Mrad except styrene which required a much larger dose of about 10 Mrad. The impregnation efficiency was found to be more for wood with high pore volume. The impregnation efficiency also depended on the ambient pressure: the more the vacuum, the more was the impregnation efficiency. Mechanical strength of the composites was found to be enhanced and water absorption considerably reduced. X-ray diffraction studies showed that the crystallinity of the cellulose did not get affected by the radiation polymerization which suggested that grafting of polymer on to the cell wall took place only in the amorphous regions.     

Fatigue life predictions for irradiated stainless steels considering void swellings effects

The objective of this study is to estimate fatigue life of irradiated austenitic stainless steels types 304, 304L, and 316, which are extensively used as structural alloys in the internal elements of nuclear reactors. These reactor components are typically subjected to a long-term exposure to irradiation at elevated temperature along with repeated loadings during operation. Additionally, it is known that neutron irradiation can cause the formation and growth of microscopic defects or swellings in the materials, which may have a potential to deteriorate the mechanical properties of the materials. In this study, uniaxial fatigue models were used to predict fatigue properties based only on simple monotonic properties including ultimate tensile strength and Brinell hardness. Two existing models, the Bäumel–Seeger uniform material law and the Roessle–Fatemi hardness method, were employed and extended to include the effects of test temperature, neutron irradiation fluence, irradiation-induced helium and irradiation-induced swellings on fatigue life of austenitic stainless steels. The proposed models provided reasonable fatigue life predictions compared with the experimental data for all selected materials.     

The design of advanced performance high strength low-carbon martensitic armour steels: Microstructural considerations

Neither a higher hardness nor higher mechanical properties (yield strength, ultimate tensile strength, impact energy, and %elongation) appear to be exclusive or even reliable criteria for predicting the ballistic performance of martensitic armour steels, as shown in our previous work [K. Maweja, W.E. Stumpf, Mater. Sci. Eng. A (February), submitted for publication]. An alternative design methodology for tempered martensitic armour steels is, therefore, proposed which is based on the effect of retained austenite on the ratio of the yield to ultimate tensile strength (YS/UTS), the microstructure of the tempered martensite and its martensite start temperature M_s. This approach was developed using 6 mm thick armour plates and later was successfully applied to the design of eight experimental armour steels with plate thicknesses ranging from 4.7 to 5.2 mm and tested by the standard R4 (5.56 mm rounds) ballistic test.     

Preparation of UV-curable intercalated/exfoliated epoxide/acrylateclays nanocomposite resins

Preparation of UV-curable intercalated/exfoliated epoxide/acrylateclays nanocomposite resins with the addition of specific monomers and solvent via the consideration of solubility parameter and chemical reactivity was carried out in this work. Due to the good compatibility with surfactant in acrylateclays and the cationic oligomer in resin matrix, the two additive monomers dispersed uniformly in resin matrix with the swollen acrylateclays before UV curing. As revealed by conversion ratio and DTG analyses, chemical bonds between the two additive monomers, the cationic oligomers and surfactant in acrylateclays were formed during UV irradiation. This, in turn, generated a hybrid acrylate-based/epoxy network and effectively enlarged the lamellae spacing of inorganic clays in nanocomposite resins prepared in this work. The XRD and TEM characterizations revealed that the intercalated clay domains containing exfoliated lamellae about 1 nm in thickness uniformly disperse in polymeric matrix. The nanocomposite resin containing 5 wt.% inorganic filler possessed the physical properties as follows: T _d-5% = 213 °C, CTE = 80.5 ppm/°C, moisture absorption = 6.12%, average optical transmittance = 83.17%, and adhesion strength on glass substrate = 43.8 kgf/cm². The analyses above indicated that the formation of polymeric interpenetrating networks and nanometer-scale exfoliation of clay lamellae not only improve the thermal properties and resistance to moisture permeation, but also retain highly optical transmittance and satisfactory adhesion strength of nanocomposite resins prepared in this work. A better device lifetime property was hence achieved when the nanocomposite resins were applied to the packaging of OLEDs.     

Mechanical properties of rat epiphyseal cancellous bones studied by indentation testing

Twenty-six pairs of rat femoral heads, distal femurs, proximal tibiae, and humeral heads were tested using an indentation test with a flat-ended cylindrical indentor. A useful mechanical data set including ultimate load, stiffness, and ultimate strength has been generated. Differences were found between the cancellous bones at different locations. Good correlations have been obtained between indentation depth (at 50 N load) and ultimate strength (R=–0.937, p<0.05), which means that with an increase of ultimate strength the indentation depth or deformation decreased proportionally. Based on the experimental results and the comparison with other methods in the literature, the simplicity and usefulness of this indentation test to evaluate compressive mechanical properties of rat epiphyseal cancellous bone are apparent.