Lap-shear strength

Polyimides of 6FDA and aUphatic diamines with good low temperature processkig and low moisture swelling are known to be useful as hot-melt adhesives (109). Aluminum strips bonded by this polymer (177°C/172 kPa (25 psi) for 15 min) exhibited a lap-shear strength of 53 MPa (7690 psi) at room temperature and 35 MPa (5090 psi) at 100°C. The heat- and moisture-resistant 6F-containing Pis useful ki electronic devices are prepared from... 

Comparison of tensile lap shear strengths solvent-based chromate-inhibited primers versus nonchromate and low VOC primers [42]... 

Primer (source) Adhesive Tensile lap shear strength (psi) ... 

Flexibilized epoxy resins are important structural adhesives [69]. Liquid functionally terminated nitrile rubbers are excellent flexibilizing agents for epoxy resins. This liquid nitrile rubber can be reacted into the epoxy matrix if it contains carboxylated terminated functionalities or by adding an amine terminated rubber. The main effects produced by addition of liquid nitrile rubber in epoxy formulations is the increase in T-peel strength and in low-temperature lap shear strength, without reducing the elevated temperature lap shear. 

St. Clair et. al. investigated a series of maleimide and nadimide terminated polyimides and developed LARC-13 [8,9]. Changing the terminal group from maleimide to nadimide, the value of the lap shear strength of a titanium lap shear joint increased from 7 to 19 MPa [9]. They also added an elastomeric component to the adhesive formulation. The introduction of 15 wt% of a rubbery component, ATBN (amine terminated butadiene nitrile polymer) and ADMS (aniline terminated polydimethyl siloxane) enhanced the adhesive properties as follows 19 MPa to 25 MPa (ATBN) titanium T-peel strength 0.2 kN/m to 1.4... 

In other studies [115], the bond strengths of joints made from steel substrates coated with a variety of oils and waxes ( 6 mg/cm ) and Joined with acrylic adhesive were investigated. Lap-shear strengths up to 15 MPa were obtained with room temperature curing. Very little degradation was seen after 1000 h of... 

Surface cleaning/etches. As with aluminum and titanium, the most critical test for bonded steel joints is durability in hostile (i.e., humid) environments. The fact that the problem is a serious one for steel was illustrated in a study [117] that compared solvent cleaned (smooth) 1010 cold-rolled steel surfaces with FPL aluminum (microrough) substrates. Although the dry lap-shear strengths were not markedly different, stressed lap-shear joints of steel adherends that were exposed to a humid environment failed in less than 30 days, whereas the aluminum joints lasted for more than 3000 days. 

Lap shear strengths for EB-cured acrylic adhesives on graphite composites... 

Adhesive Curing dose (kGy) Man. specs. Lap shear strength (MPa) ... 

Man. specs. = Manufacturer specification. Lap shear strength on steel. 

There has been very little work done on the development of EB-curable epoxy adhesives. When undertaking this development work the authors had two objectives. The first objective was to develop a series of adhesives for bonding aluminum-to-aluminum (Al-Al) and composite-to-composite (C-C) with lap shear strengths of 30 MPa or greater at room temperature. The second objective was that the... 

We have also looked at the lap shear strength of selected EB-ciirable epoxy adhesives. Because the adhesives being developed were being used for both aluminum-to-aluminum and composite-to-composite applications the lap shear strengths for both adherends was measured. Aluminum adherends were T2024 phosphoric acid anodized according to ASTM 3933. The composite adherends... 

Lap shear strengths (MPa) of selected EB-cured epoxy adhesives at various temperatures... 

Effects on lap shear strength of EB-cured epoxy adhesives from different surface preparations on aluminum and composite adherends... 

Patel et al. [70] in a recent publication have explored the adhesive action of the mbber-siUca hybrid nanocomposites on different substrates. The rubber-silica hybrid nanocomposites are synthesized through in situ silica formation from TEOS in strong acidic pH within acryhc copolymer (EA-BA) and terpolymer (EA-BA-AA) matrices. The transparent nanocomposites have been apphed in between the aluminum (Al), wood (W), and biaxially oriented polypropylene (PP) sheets separately and have been tested for peel strength, lap shear strength, and static holding power of the adhesive joints. 

Table 16.6. Lap Shear Strengths ofOxyfluorinated and Fluorinated PE with Pro-Struct 30/71 ...

Table 16.7. Lap Shear Strengths of Surface Fluorinated PE after ...

Table 16.8. Typical Lap Shear Strengths for HDPE and PP Activated by Fluorination and...

Since the m,m -DABP polyimide is known to be an outstanding adhesive, lap shear strength tests employing titanium-titanium adherends and metal ion filled polyimides were conducted. Tests were performed at room temperature, 250°C and 275°C employing either DMAC or DMAC/Diglyme as the solvent. At room temperature regardless of the metal ion employed adhesive strength is de-... 

Figure 1. Lap shear strength as a function of equivalent ratio of epoxide to N-cyanourea.

ISO 1926 1979 Cellular plastics - Determination of tensile properties of rigid materials ISO 4587 2003 Adhesives - Determination of tensile lap-shear strength of rigid-to-rigid... 

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