氨基硅烷偶联剂

介绍了氨基硅烷偶联剂的种类，物性，合成，用途及使用工艺，重点概述了氨基硅烷偶联剂的合成原理及具体实验方法。     

塑料的填充改性与偶联剂的应用

以聚合物为基材、无机矿物为填充材对塑料进行填充增强改性。文中讨论了填料品种、形状、粒径、堆砌分布以及表面结构对塑料的改性影响,并对偶联剂的品种、使用方法及填料表面处理的判断方法进行了讨论。     

导电胶的研究与发展

介绍了导电胶的组成与类别,从宏观和微观角度对几种导电机理进行了概述。从实验研究的角度,介绍了导电胶体积电阻率的测定方法和导电胶性能影响因素。分析了组成成分和固化工艺对导电胶性能的影响,如导电粒子的形貌和尺寸、树脂基体种类、固化温度、固化时间和湿热老化条件等对粘接性能和导电性的影响。指出了在固化过程中,树脂基体与导电粒子的匹配和润湿包覆作用对导电性能的重要影响。简单介绍了现今几种中温固化导电胶的性能,对研究方向作了展望。     

导电增韧聚甲醛的制备及性能

探讨了炭黑和抗静电剂改性硅油分别使用与协同使用对聚甲醛(POM)导电性能和力学性能的影响,同时研究了增韧剂聚氨酯弹性体(TPU)对POM导电性能和力学性能的影响。结果表明:炭黑和改性硅油配合使用,可使POM的表面电阻率达到102Ω,而其力学性能也比单独使用炭黑有所改善。增韧剂TPU进一步提高了导电POM的冲击强度,但使导电POM的表面电阻率增加到106Ω。     

有机硅烷偶联剂对丙烯酸酯胶粘剂粘接作用的研究

利用剪切粘接强度、SEM等方法 ,考察了有机硅烷偶联剂的种类和处理方法对丙烯酸酯类胶粘剂 ,粘接强度的影响。结果表明 :将偶联剂KH - 570预处理物体表面及掺入乳液、适当高的固化温度都能显著地提高粘接强度。     

LDPE／炭黑复合导电材料性能的研究

总结了１８２批西洋参的鉴别检验，其结果显示外观性状鉴别与薄层色谱鉴别结果相符率为９４．０％。因此西洋参真伪鉴别检验每批样品除进行状检验外还必须做薄层分析，以防止白参掺入或下错结论。     

Electrical Properties of Pre-Alloyed Cu-P Containing Electrically Conductive Adhesive

In this study, a pre-alloyed Cu-P powder with a trace amount of P (0.002 at.%) was used as a metallic filler in a phenolic resin-based electrically conductive adhesive (ECA). The electrical property of the Cu-P-filled ECA was investigated for long-term stability and reliability by aging at high temperature exposure at 125°C and 85°C/85% RH for 1000 h, respectively. Results showed that the electrical resistivity of the Cu-P-filled ECA could be maintained consistently low after high temperature exposure at 125°C for 1000 h or aging at 85°C/85% RH for 1000 h, compared with the rapidly increased resistivity of Cu-filled ECA over time. A significantly low final resistivity at an order of magnitude of 10^?4 Ω·cm could be maintained in Cu-P-filled ECA even after aging at 85°C/85% RH for 1000 h.     

导电银胶在电磁屏蔽材料上的研究与应用

以片状银粉作为导电介质,以环氧树脂、固化剂、促进剂混合为成膜剂制备出可用于电磁屏蔽,具有良好力学性能的导电银胶。讨论了银粉在银胶中质量分数为75％、81％时,固化后银胶在100kHz～18GHz波段的电磁屏蔽性能,银含量越高对15M～18GHz高频率波段电磁屏蔽效能越好,可达到17～51dB。分析了银胶导电性与电磁屏蔽功效之间的关系;通过扫描电镜的观察,从微观上进一步验证其电磁屏蔽作用;当银含量为81％时其拉伸强度为1．20MPa。     

Conduction Efficiency and Strength of Electronically Conductive Adhesive Joints

Electronically conductive adhesives are being considered as an alternative to solder for interconnection in microelectronics. In order to gain insight regarding electrical and mechanical performance properties of this class of adhesive interconnections, overlap joints were made. Joint resistance and mechanical bond strength were measured before and after environmental stressing.     

Conduction Efficiency and Strength of Electronically Conductive Adhesive Joints

Electronically conductive adhesives are being considered as an alternative to solder for interconnection in microelectronics. In order to gain insight regarding electrical and mechanical performance properties of this class of adhesive interconnections, overlap joints were made. Joint resistance and mechanical bond strength were measured before and after environmental stressing.     

片材挤出用导电聚碳酸酯工程塑料的研制

采用熔融共混法制备了导电炭黑/聚碳酸酯(PC)片材挤出用导电复合材料,研究了炭黑、增韧剂等对复合材料的表面电阻率、力学性能、剥离强度和外观的影响。结果表明:将炭黑添加到PC中制得的导电复合材料可挤出合格的用于载带制造的片材,可以满足芯片包装的各项要求,适宜的炭黑加入量为16%~23%;甲基丙烯酸甲酯-丁二烯-苯乙烯共聚物(MBS)、丙烯腈-丁二烯-苯乙烯共聚物(ABS)均可作为导电PC复合材料的增韧剂,但以两者共混时的焊接剥离强度最为稳定,片材的外观良好,适宜用量为5%~7%。     

Hygrothermal Properties of Adhesively Bonded Joints and Their Correlation with Bulk Adhesive Properties

The combined effects of heat (50[ddot]C) and humidity (95% R.H.) on the lap shear and T-peel strengths of 120[ddot]C, 150[ddot]C and 215[ddot]C service epoxy film adhesives have been characterized. Experimental results have indicated that effects of hygrothermal conditioning on lap shear and peel properties vary with exposure time and final testing temperatures and type of adhesive tested. In the cases where cohesive failure was observed in the shear and peel specimens, a correlation could be established between the bulk properties of the adhesives (tensile strength and elongation) and their adhesively bonded joint properties (shear and peel). When testing was carried out at room temperature, a general correlation between the tensile elongation and T-peel or shear could be obtained. At below freezing temperatures, lap shear strength seemed to be correlated with bulk tensile strength while peel correlated with bulk tensile elongation. At elevated temperatures, the relative contributions of bulk strength and elongation were the decisive factors as far as shear and peel strengths are concerned.     

Temperature and time dependence of conductive network formation: Dynamic percolation and percolation time

Temperature and time dependence of conductive network formation in vapor-grown carbon fiber (VGCF) filled high-density polyethylene (HDPE)/poly(methyl methacrylate) (PMMA), VGCF and ketjenblack (KB) filled HDPE/isotactic polypropylene (iPP) blends have been investigated. It is found that the filled conductive polymer composites are thermodynamically non-equilibrium systems, in which the conductive network formation is temperature and time dependent, a concept named as dynamic percolation is proposed. When the composites are annealed at a temperature above the melt point of polymer matrix, the dynamic process of conductive network formation can be monitored in a real time way. Such an in situ characterization method provides more interesting information about the dispersion of conductive particles in the polymer matrix. Furthermore, a thermodynamic percolation model is modified to predict the percolation time for VGCF and KB filled HDPE/iPP multi-phase systems during the annealing treatment, and it expresses experimental results well.     

Adhesive Properties of Cured Phenylethynyl-Terminated Imide Oligomers

As part of a program to develop structural adhesives for high performance aerospace applications, phenylethynyl-terminated imide oligomers are under evaluation. Imide oligomers with different molecular weights and compositions endcapped with either 4-(3-aminophenoxy)-4'-phenylethynylbenzophenone (3-APEB) or 4-phenylethynylphthalic anhydride (PEPA) have been prepared and characterized. These oligomers exhibit excellent processability. After heating to 350°C for 1 hour, the terminal phenylethynyl groups have reacted to provide chain extension, branching and crosslinking. The cured polymers exhibit excellent solvent resistance and high mechanical properties as neat resins and in various adhesive forms (tensile shear, sandwich flatwise tension and climbing drum peel specimens). The chemistry and properties of these phenylethynyl-terminated imide oligomers are discussed.     

Comparison on the Properties of Nickel-Coated Graphite (NCG) and Graphite Particles as Conductive Fillers in Polypropylene (PP) Composites

The present study was carried out to evaluate the performance of nickel-coated graphite (NCG) in comparison with graphite as conductive fillers in polypropylene (PP) matrix. Graphite exhibits smaller particle size and higher aspect ratio (length/thickness) than NCG particles. The results showed that the additions of graphite filler in PP exhibits higher tensile properties and electrical conductivity compared to NCG filled PP composites. The electrical results showed that the percolation threshold of graphite and NCG filled PP composites occurred in the range of 10 to 20 vol.% and 15 to 25 vol.%, respectively.     

Effect of Curing Procedures on the Electrical Properties of Epoxy-Based Isotropic Conductive Adhesives

The effects of different curing and post-heating treatment procedures on the electrical properties of isotropic conductive adhesives (ICAs) were investigated in this work. The results showed that the bulk resistivity of ICAs cured by multi-step method was lower than that cured by the one-step method, even though they were cured for the same periods. It was also found that the electrical resistance of ICAs continued to decrease during the subsequent post-heating treatment processes. The in situ monitoring the variations in electrical resistance was studied during the curing and post-heating treatment process, and it was found that the cooling process continued to decrease the electrical resistivity of ICAs. The trend of the evidence has been consistent and indicated that the internal stress of ICAs, which depended on the curing and post-heating treatment temperatures, had a significant effect on the electrical resistivity of ICAs. Meanwhile, it was proved that the bulk resistivity of ICAs increased as the internal stress of ICAs weakened by the addition of PEG.     

不同硅烷偶联剂对氧化镁填充导热尼龙6性能的影响

分别用四种不同的硅烷偶联剂处理氧化镁,研究了不同偶联剂表面处理后的氧化镁填充尼龙-6导热复合材料的力学性能、热变形温度和导热性能。结果表明,硅烷偶联剂处理后氧化镁/尼龙6复合材料的强度、刚性和导热性能明显提高,热变形温度则略有上升。四种硅烷偶联剂对氧化镁表面处理效果从好至差依次顺序为KH792KH550KH160KH560。     

Silane Coupling Agents as Adhesion Promoters for Aerospace Structural Film Adhesives

The performance of eight organofunctional silane coupling agents as adhesion promoters for the bonding of aluminium with two 121°C and two 177°C curing structural film adhesives was investigated and compared to the chromic acid (FPL) etch pre-treatment process and two non-chemical pretreatments. Aspects considered were shear strength of joints at ambient and elevated temperatures and durability, as judged by the wedge test.

The epoxy silane, γ-glycidoxypropyltrimethoxy silane, was found to be a very efficient adhesion promoter with all film adhesives evaluated. The cationic styryl silane, a neutral diamine monohydrochloride, showed promise with two adhesive systems. Four other neutral silanes were less effective.

Performance of amine functional silanes was mixed. Although the shear strength of joints with the primary amine silane at its natural pH of ∼10.3 was relatively good, durability was poor. However, good durability was obtained if the primer was first adjusted to pH 8 with hydrochloric acid, but not if acetic or phosphoric acids were used. Diamine silane was not an effective adhesion promoter at either its natural pH or when acidified with hydrochloric acid.     

Influence of Electron Beam Irradiation and Coupling Agents on the Thermal Stability of Sugar Cane Bagasse Fiber-Thermoplastics Scrape Composite

The influence of blending of sugar cane bagasse with thermoplastics scrape as well as incorporation of some coupling agents has been conducted using thermogravimetric analysis (TGA). In addition, the effect of electron beam preirradiation of low density polyethylene on the properties of the bagasse-LDPE composite was also studied. Simulation of TGA data reveals that the presence of bagasse fiber accelerates the volatilization of either polypropylene or polyvinylchloride. On the other hand, polyethylene and polystyrene were stable against the heat evolved during the pyrolysis of bagasse fibers. Also, it was found that incorporation of a mixture of pentaerithrol tetraacrylate (PETA) and dicumyl peroxide (DCP) as coupling agents improve the thermal stability of low density polyethylene whereas the role of irradiation was insignificant. Moreover, pronounced enhancement in the thermal stability was detected in polypropylene followed by polystyrene and polyvinylchloride on using PETA.     

Shear Property of Kaolin-filled Standard Malaysian Rubber (SMR L) Pressure-sensitive Adhesive

The effect of kaolin loading on the viscosity and shear strength of natural-rubber-based pressure-sensitive adhesive was studied using coumarone-indene resin, toluene, and polyethylene terephthalate as tackifier, solvent, and substrate, respectively. Kaolin loading ranged from 10 to 60 parts per hundred parts of rubber (phr) whereas the tackifier content was fixed at 40 phr. The viscosity and shear strength—from lap shear test—were determined by a Brookfield viscometer and Lloyd adhesion tester, respectively. Results show that viscosity increases with increasing kaolin loading. However, shear strength increases up to 20 phr kaolin loading, after which it decreases with further filler loading. This observation is attributed to the culmination of cohesive strength at the optimum loading of kaolin filler. For a fixed kaolin loading, the shear strength increases with coating thickness and testing rate.