内置胶囊混凝土的裂缝自愈合行为分析和试验

研究了一种具有裂缝自愈合行为的内置胶囊混凝土．首先,建立了描述修复胶囊在混凝土中的分布和取向函数;然后,根据混凝土的破坏机理,确定了修复胶囊的破坏应力;第三,通过实验分析了修复胶囊的几何参数和体积率对混凝土性能的影响,得到了几何参数和体积率的最佳取值范围;第四,利用ANSYS对修复胶囊进行了有限元分析,确定了其合理的壁厚,为修复胶囊材料的选择提供了一种研究方法;最后,进行了内置胶囊混凝土试验,取得了一定的自愈合效果。     

鞋用水性聚氨酯胶黏剂的制备及表征

通过预聚体分散法,以二羟甲基丙酸(DMPA)、蔗糖(sucrose)为亲水扩链剂和交联剂制备了一种鞋用水性聚氨酯胶黏剂.通过FTIR、DSC、力学性能、固化速度等研究了蔗糖用量对聚氨酯结构与性能的影响.结果表明蔗糖己引入聚氨酯主链.随着蔗糖用量的增加,相同处理温度下聚氨酯胶液的固化速度提高,胶膜的吸水率降低,拉伸强度增大,断裂伸长率减小,粘接试样的T-剥离强度逐渐增大.当蔗糖用量超过5.52 wt%时,合成及乳化过程中体系容易凝聚,且所制得的胶黏剂粘接强度有所下降.总之,通过改变蔗糖用量可以显著改变水性聚氨酯结构与性能.     

Viscoelastic Behavior and Force Nature of Thermo‐Reversible Epoxy Dry Adhesives

The gecko adhesion phenomenon has stimulated efforts to produce synthetic patterned dry adhesives. Besides introducing surface patterns on dry adhesives, it is also highly desirable to understand their intrinsic material properties. This communication reports the viscoelastic behavior of non‐patterned epoxy elastomers exhibiting intrinsic adhesion that is much higher than that of elastomers typically used for structure patterning. The diverse molecular origin of the adhesion is revealed through the study of adhesion against various substrates.

     

The improvement of thermal stability and adhesion of silicone rubber composites modified by phenolic epoxy resin

The phenolic epoxy resin (F51) was siliconized by KH550 and the product was named as FKS. A hydroxyl-terminated polydimethylsiloxane (HTPDMS) which was modified with FKS was prepared. The siliconization reaction ensured a segment of siloxane on the side chain of F51. FT-IR and ¹H-NMR were employed to confirm the chemical structure of FKS. Morphology observations revealed that the enhancement of mechanical properties of the silicone rubber systems can be attributed to good compatibility between FKS and silicone rubber matrix. Thermogravimetric analysis showed that the residual yield at 800?°C of silicone rubber composites increased significantly when compared with that of neat HTPDMS. The mechanical properties demonstrated that tensile strength and elongation at break of silicone rubber system increased distinctly after modification, especially when 30 phr siliconized F51 were added to the silicone rubber. Shear strength was improved gradually with the addition of FKS. These above observations emphasize the vital effect of FKS on the behavior of modified HTPDMS.     

Electrically conductive epoxy‐based nanocomposite adhesives loaded with silver‐coated copper and silver‐coated reduced graphene oxide nanoparticles

In this research, a conductive adhesive based on epoxy resin as the polymer matrix and silver‐coated copper powder and silver‐coated reduced graphene oxide as conductive fillers was synthesized. Graphene oxide was synthesized by modified Hummer's method. It was reduced and modified by silver powder. Copper particles were coated with silver using the electroless plating method. Finally, conductive nanocomposite adhesives were prepared using conductive fillers with different weight fractions. The structural properties of fillers were identified by Fourier‐transform infrared (FTIR) and induced coupled plasma (ICP) analysis and the morphology of the samples by scanning electron microscopy (SEM). Finally, conductive properties, lap shear strength, and thermal stability of adhesive were evaluated. The conductive adhesive prepared with optimized properties have 70% weight percentage silver‐coated copper powder and 1% weight percentage silver‐coated reduced graphene oxide. The bulk resistivity of the optimum sample was 1.6 × 10^‐2 Ω.cm, and the lap shear strength was 7.10 MPa. Also, thermogravimetric analysis showed that the weight loss of adhesive decreased from 88.72% to 30.55% during heating, which showed the addition of fillers improves the thermal stability of adhesive.     

气相色谱法同时测定溶剂型胶黏剂中的9种有害物质

建立了利用毛细管柱气相色谱同时测定溶剂型胶黏剂中苯、 甲苯、 对（间）二甲苯、 邻二甲苯、 二氯甲烷、1,2-二氯乙烷、1,1,2-三氯乙烷、三氯乙烯、甲苯二异氰酸酯（TDI）的方法,并对样品中有害物质的分离提取和色谱条件进行了研究.实验结果表明,方法化合物浓度在10~300 μg/mL时,线性相关系数不低于0.999 1,样品加标回收率在91.2%~104.1%之间,相对标准偏差均小于5%,检出限为0.1~3.0 μg/mL.方法不仅回收率高、重现性好,而且简便、快速.     

金属膜层对光纤表面等离子传感器的影响研究

采用SG-12SA作为镀膜设备, 研究了当金膜厚度相同的情况下, 光纤表面等离子体波传感器在有粘结层和无粘结层时的光谱特性; 当粘结层厚度相同时, 光纤表面等离子体波传感器对应不同金膜厚度的光谱特性。结果表明：对镀有同样金膜厚度的光纤表面等离子体波传感器, 纤芯与金膜之间有粘结层相对于无粘结层, 共振波长出现红移, 且共振深度减小; 对镀有同样粘结层厚度的光纤表面等离子体波传感器, 随着金膜厚度的增加, 共振波长亦逐渐发生红移。这些研究成果为以后研制性能优良的光纤传感器提供了参考, 同时为在直径为微米级的三维圆柱面上镀膜提供一定的指导意义。     

静电喷涂法制备具有低吸附力的超疏水性聚苯乙烯膜

采用聚苯乙烯的N,N-二甲基甲酰胺溶液为原料, 通过静电喷涂的方法制备了具有微-纳米复合结构的聚苯乙烯膜. 通过调节溶液浓度, 得到了不同的结构、浸润性及吸附性的表面. 当聚苯乙烯的质量分数为5%、分子量为25000时, 得到的表面与水的接触角达到167°, 吸附力达到15 μN, 表明该膜表面具有超疏水性的同时对水滴具有很低的吸附力. 此外, 分子量的大小也对静电喷涂膜表面形貌的变化起重要的作用.     

铝合金表面复合陶瓷防火涂层的制备及性能研究

以无机胶粘剂及陶瓷粉体为原料,制备用于地铁内饰的铝合金板表面阻燃陶瓷涂层.研究了胶粘剂、无机阻燃剂的加入量及料浆粒度与涂层致密度的关系.按照饰面型防火涂料的国家标准(GB12441-2005)和材料非燃性的英国标准(BS476-4)对涂层的理化性能进行检测.结果表明:当粘结剂的用量为60;、添加剂粒度为1～2 μm时,涂层表面均匀、致密、无缩孔.所制备的陶瓷涂层均达到上述标准.涂层的耐火极限高于30 min,不燃,不脱落,无烟,不产生有毒的气体,具有很好的防火阻燃作用.     

用侧向力显微镜对不同非晶态GeSbTe薄膜的摩擦性能研究

采用侧向力显微镜研究了磁控溅射方法制备的GeSbTe薄膜在大气环境中的纳米级摩擦性能,考虑了相对湿度、扫描速度及表面粗糙度对其摩擦性能的影响,对比不同成分的GeSbTe薄膜的摩擦特性.结果表明:在相对湿度较大时,扫描速度对针尖和GeSbTe薄膜之间的摩擦力影响很大;在其它条件相同、外加载荷较大时,同一载荷下的摩擦力与表面粗糙度呈线性关系,但在外加载荷较小的情况下,二者呈现非线性变化规律;相对湿度对Ge2Sb2Te5薄膜和针尖的粘附力影响较GeSb2Te4薄膜弱,且粘附力使得摩擦系数减小;在同一相对湿度下,由于薄膜成分的变化导致硬度不同,其对薄膜的摩擦性能也有一定影响.