Adhesive Evaluation for New Forms of LARCTM-TPI

LARC^TM-TPI is a linear aromatic polyimide that was developed at NASA Langley Research Center in the 1970's and subsequently licensed to Mitsui Toatsu Chemicals, Inc., (MTC) in Japan. This company has made it easier to process for use in application as a structural adhesive or as a composite matrix resin. The present forms that exist are (1) high melt viscosity or Low Flow Grade (LFG); (2) medium melt viscosity or Medium Flow Grade (MFG); and (3) low melt viscosity or High Flow Grade (HFG). As expected, the low melt viscosity material is the easiest to process but has poor toughness; the high melt viscosity material is very tough but is more difficult to process. Because of these two extreme situations we have worked closely with MTC to develop an optimized system. This work has resulted in the medium melt viscosity material as well as two other modified or blended medium-flow variations.

These novel forms of LARC^TM-TPI have resulted in adhesives that can be melt processed at pressures as low as 0.01 MPa (15 psi) at temperatures between 343-371°C (650-700°F). Evaluation of adhesive performance has been accomplished using lap shear specimens and evaluating flow, wet out and shear strength. Initial strengths for these optimized materials range from 20.7-41.4 MPa (3000-6000 psi) at room temperature and 13.8-20.7 MPa (2000-3000 psi) at elevated test temperatures.     

Adhesive Evaluation for New Forms of LARCTM-TPI

LARC^TM-TPI is a linear aromatic polyimide that was developed at NASA Langley Research Center in the 1970's and subsequently licensed to Mitsui Toatsu Chemicals, Inc., (MTC) in Japan. This company has made it easier to process for use in application as a structural adhesive or as a composite matrix resin. The present forms that exist are (1) high melt viscosity or Low Flow Grade (LFG); (2) medium melt viscosity or Medium Flow Grade (MFG); and (3) low melt viscosity or High Flow Grade (HFG). As expected, the low melt viscosity material is the easiest to process but has poor toughness; the high melt viscosity material is very tough but is more difficult to process. Because of these two extreme situations we have worked closely with MTC to develop an optimized system. This work has resulted in the medium melt viscosity material as well as two other modified or blended medium-flow variations.

These novel forms of LARC^TM-TPI have resulted in adhesives that can be melt processed at pressures as low as 0.01 MPa (15 psi) at temperatures between 343–371°C (650–700°F). Evaluation of adhesive performance has been accomplished using lap shear specimens and evaluating flow, wet out and shear strength. Initial strengths for these optimized materials range from 20.7–41.4 MPa (3000–6000 psi) at room temperature and 13.8–20.7 MPa (2000–3000 psi) at elevated test temperatures.     

改性CRL接触胶的制备及其对多孔材料的粘接机制

以CRL-g-MMA[甲基丙烯酸甲酯(MMA)接枝改性氯丁胶乳(CRL)]、苯丙乳液(SAE)为基料,配合适当助剂,制得多孔材料粘接用二元改性CRL接触胶。考察了SAE含量对该接触胶粘接性能的影响,并分析了该接触胶对多孔材料的界面粘接机制。结果表明:当w(SAE)=50%(相对于接触胶总质量而言)时,该接触胶的剥离强度相对最大(5.5 N/mm);将该接触胶应用于多孔材料(棉帆布/棉帆布)的粘接复合时,表现出明显的"锁-匙"效应,有利于形成牢固的机械胶合,这也是其粘接性能良好的原因之一。     

我国鞋用胶粘剂的市场与展望

目前,我国年产鞋量为60亿双,随着经济的增长,在加入WTO后,我国年产鞋量可稳定在70亿~80亿双。溶剂胶制造简单、使用方便、粘合力强,是广泛使用的大底胶,但环境污染严重,即将面临着被环保型胶取代的局面;具有环保性的热熔胶可用于绷帮、涂包头、鞋帮部件抿边、粘衬里、包鞋跟和面料复合,但用它来粘大底,还满足不了穿着的要求,须从增强分子间作用力和快速渗透功能两方面改进;水基胶尽管还存在粘合强度不高、水分蒸发慢等不足,但由于是目前污染最少的胶种而倍受关注;无溶剂胶省去了聚合、溶解、挥发干燥等诸多程序,同样也具有广阔的发展前景。     

聚酯型HMA胶膜AS 615的性能研究

自制AS 615是一种新开发的特种聚酯型HMA(热熔胶)胶膜,具有良好的综合性能;以此作为电子产品塑料外壳/金属部件的胶粘剂,并对其应用性能进行了系统研究。结果表明:AS 615对ABS(丙烯腈-丁二烯-苯乙烯共聚物)、PC(聚碳酸酯)等极性塑料和金属具有良好的粘接性能,相应胶接件稳定后的剥离强度超过65 N/25 mm,其最佳粘接复合温度范围为120～160℃;AS 615具有良好的耐水性、耐老化性和粘接持久性,可取代国外同类产品用于电子行业中极性聚合物与金属之间的粘接。     

An Experimental Study of the Static Torque Capacity of the Adhesively-Bonded Tubular Single Lap Joint

With the wide application of fiber-reinforced composite materials in aircraft, space structures and robot arms, the design and manufacture of composite joints have become a very important research area because they are often the weakest areas in composite structures. In this study, the effects of the adhesive thickness and tensile thermal residual stress on the torque capacity of tubular single lap joints were studied. The torque capacities of the adhesive joints were experimentally determined and found to be inversely proportional to the adhesive thickness. In order to match the experimental results to the theoretical analyses, the elastic-perfectly plastic material properties of the adhesive were used in the closed form solution. Also, the tensile thermal residual stresses of the joints were calculated by the finite element method and it was found that the thermal residual stresses could play an important role in the torque capacity when the adhesive thickness was large.     

国内中空玻璃用MS胶的市场现状及选用建议

介绍了MS胶名称的由来、性能特点、市场应用情况及国内中空玻璃用MS胶的性能检测情况,从检测结果看出,目前国内市场中空玻璃用MS胶不能完全满足GB/T 29755《中空玻璃用弹性密封胶》标准要求,用于中空玻璃后易造成玻璃脱粘、开裂,导致中空玻璃出现漏气、漏水等提前失效现象,不利于有效地保持中空玻璃的长久使用,故暂不建议用于中空玻璃。     

Study on benzoxazine-based film adhesive and its adhesion properties with CFPR composites

In this paper, a benzoxazine-based (BZ) adhesive with high temperature resistant was developed by blending benzoxazine monomer and tetrafonctional epoxy monomer as matrix modifier and polyetherimide as toughening agent. The results show that benzoxazine-based film adhesive could be cured at 190 °C, and the cured film adhesive exhibited high temperature resistance and a high glass transition temperature of 224 °C. The 5% weight loss temperature in air was 400 °C and the char yield in nitrogen at 800 °C was 48%. The cured film adhesive has good ablation resistance. The fabricated benzoxazine-based film adhesive has high adhesion reliability, with single-lap shear strength of 23.20, 28.36 and 20.04 MPa at room temperature, 140 and 175 °C respectively. The curing process of the film adhesive matches well with that of carbon fiber reinforced BZ prepreg and the film adhesive has stable adhesion properties. Its biggest advantage is that, during storage and transportation, there is no need of refrigeration. After 60 days of storage for benzoxazine-based film adhesive at room temperature, its process performance and adhesion properties remain unchanged. It is expected that the benzoxazine-based film adhesive can be used in aerospace, high-speed rail and other applications.     

生物油对生物油基淀粉胶黏剂性能的影响

我国的生物质资源丰富,将其快速热解成生物油,作为优质化工原料应用,可实现其高值高效应用。本文对以生物油制备的环境友好型生物油淀粉胶黏剂基本性能进行研究,结果表明,其湿胶合强度可达到国标Ⅱ类胶合板标准,其黏度可以满足胶合板工业化生产需求;生物油淀粉胶黏剂流变行为呈现出明显的剪切变稀特征,是典型的假塑性流体,流动活化能△E_η为9.67 kJ·mol^-1,表明其具有良好的流动性和应用潜力;通过对比不同生物油加入量的BOS胶黏剂湿胶合强度、流变性和热稳定性的研究发现,生物油的加入可改善BOS胶黏剂的耐水性,促进其固化,并增强其热稳定性。     

氰酸酯改性双马来酰亚胺耐高温胶粘剂

研制了一种氰酸酯改性双马来酰亚胺耐高温胶粘剂,探讨了双官能度氰酸酯与双马来酰亚胺的共聚机理,得出两者并非各自聚合形成互穿网络结构,而是发生共聚形成新的化合物的结论。该胶工艺性良好, 对钢、铝等材料具有良好的粘接性能,耐高温老化性能优良。热失重(TG)分析表明,该胶热失重起始温度为 355．85℃,热分析和性能测试结果表明该胶可以在230℃长期工作。     

稳定快干性淀粉胶粘剂的制备

以玉米淀粉为原料，采用氧化改性法，配以快干剂，保护剂。研制出了稳定快干性淀粉胶粘剂。自然干燥时间比普通淀粉胶粘剂缩短14h以上，贮存期提高了90d以上。     

耐高温环氧树脂胶粘剂的研制

介绍了一种无溶剂２００℃固化２ｈ,耐高温２５０℃环氧树脂胶粘剂,具有良好的耐热和耐湿热老化性。用于航空发动机的制造和修理。     

衬布用聚氨酯热熔胶粉的研究

衬布业界非常期盼聚氨酯热熔胶粉的面世,以进一步提高衬布的品质.但自上世纪90年代以来的研究报道却表明,这一设想并不乐观.首先现有的聚氨酯热熔胶并不完全能满足衬布业的需要,其次对聚氨酯的粉碎有一定的困难.通过研究,采用化学粉碎法,用不同细化助剂进行粉碎实验,找到了一种可以使普通聚氨酯热熔胶粉碎成胶粉的有效途径.可制备出满足衬布行业性能要求的粉末.结果表明,相同粘接条件下,聚氨酯热熔胶粉的剥离强度比聚乙烯衬布用热熔胶粉大一倍以上.     

改性干酪素标签胶的研制

介绍了一种干酪素标签胶的研制方法 ,该产品用于啤酒瓶标签的粘接 ,具有初粘力强 ,性能稳定 ,低成本等优点。     

碳基复合材料用耐高温胶黏剂的研制

采用耐热酚醛树脂杂化了磷酸盐胶黏剂,以纳米氧化铝、氧化锆和氧化锌为固化剂,制备了一种对C/C和C/SiC复合材料具有良好粘接性能的胶黏剂。通过不同测试温度下的剪切强度,差示扫描量热仪（DSC）,热失重（TG）以及扫描电子显微镜（SEM）探究了杂化胶黏剂的力学性能、固化行为、耐热性能以及高温下胶黏剂结构的变化。结果表明：酚醛树脂的加入,保持了耐热性能,降低了体系固化的固化温度,有效地提高了磷酸盐胶黏剂对C/C、C/SiC两种复合材料力学性能,室温下剪切强度均高于10MPa。     

废聚酯在聚酰胺热熔粘合剂合成中的应用

以010树脂为主要原料,在实验室合成的聚酰胺热熔胶的基础上,用废聚酯代替部分原料,合成出具有极好柔韧性,较高粘度和软化点的新型聚酰胺热熔粘合剂。通过考察废聚酯的加入量和其它的合成条件的影响,找到合成的最佳配比及条件。所得聚酞酰热熔粘合剂产品在性能上能够与进口产品相媲美。由于采用废聚酯为部分原料,为解决白色污染开辟了一个新的途径。     

一步氧化法合成氧化淀粉粘合剂

常温常压下,以淀粉为原料,次氯酸钠为氧化剂,经过一步氧化法来制取氧化淀粉粘合剂.该粘合剂具有粘度大、流动性好、用途广泛等特点.淀粉和水的比例、氧化剂的用量、反应时间的长短是影响胶的性能的主要因素.通过实验确定了原料的最佳配比及合成工艺.经过性能测试,认为具有实际应用价值.     

Mode II Fracture Toughness of a Brittle and a Ductile Adhesive as a Function of the Adhesive Thickness

The main goal of this study was to evaluate the effect of the thickness and type of adhesive on the Mode II toughness of an adhesive joint. Two different adhesives were used, Araldite ® AV138/HV998 which is brittle and Araldite 2015 which is ductile. The end notched flexure (ENF) test was used to determine the Mode II fracture toughness because it is commonly known to be the easiest and widely used to characterize Mode II fracture. The ENF test consists of a three-point bending test on a notched specimen which induces a shear crack propagation through the bondline. The main conclusion is that the energy release rate for AV138 does not vary with the adhesive thickness whereas for Araldite 2015, the fracture toughness in Mode II increases with the adhesive thickness. This can be explained by the adhesive plasticity at the end of the crack tip.     

Selected aspects of epoxy adhesive compositions curing process

The paper focuses on selected parameters of curing process – temperature and time. The tests aimed at evaluating the impact of short-term thermal recuring on 1050A and 2017A aluminium alloy sheet adhesive joints strength. Joints were formed with two different adhesives, the main component of which was in both cases epoxy resin Epidian 53 and two different cure agents – poliamineamide C (PAC) and triethylenetetraamine (PF) curing agents. Curing conditions – first curing time, recuring time and recuring temperature – were modified for each of the four tests conducted. For the sake of comparative analysis, adhesive joints were subjected to a single-stage cure cycle at ambient temperature. A two-stage cure cycle of both Epidian 53 compositions at 80?°C for 1 and 2?h produces a material of different mechanical properties than the same material which submits a single-stage cure cycle at ambient temperature, as well as at 60?°C for 30?min. Simultaneously, Epidian 53/PF/100:50 composition proves to produce higher joint strength after recuring than Epidian 53/PAC/100:80; the strength of a joint formed with the former composition increases up to 50% when compared with joints subjected to a single-stage cure cycle. Moreover, tests show that recuring of the adhesive joint formed with both compositions at 60?°C for 30?min does not have a considerable influence on either 1050A or 2017A aluminium adhesive joint strength.     

Application of Adhesive Joining Technology for Manufacturing of the Composite Flexspline for a Harmonic Drive

A new manufacturing method for the cup-type composite flexspline for a harmonic drive was developed using adhesive joining technology to obviate the manufacturing difficulty of the conventional one-piece cup-type steel flexspline and to improve the dynamic characteristics of the flexspline.

In this method, the boss, tube and tooth sections of the flexspline were designed and manufactured separately, and adhesively bonded. The tube section was manufactured with high strength carbon fiber epoxy composite material and its dynamic properties were compared with those of the conventional steel flexspline.

The torque transmission capability of the adhesively-bonded joint was numerically calculated using the nonlinear shear stress-strain relationship which was represented by an exponential form.

From the test results of the manufactured composite flexspline and the conventional steel flexspline, it was found that the manufactured composite flexspline had better torque transmission characteristics. Also, it was found that the damping capacity of the composite flexspline was considerably improved.