Adhesive bond strength tests mechanical

Deflection temperature under load (DTUL) measures the temperature at which a specimen of a certain geometry deflects a fixed amount under a very specific set of conditions. However, it is often used in material selection as a measure of the maximum continuous use temperature for that material. The development of dynamic mechanical analysis (DMA) has shown that traditional DTUL test results often give a false measure of the thermal performance of polymeric materials. By measuring the elastic modulus versus temperature by DMA the thermal profile of any polymer can be obtained and a more realistic assessment of the elevated temperature performance can be obtained. New techniques were also presented for testing adhesive bond strength tests for piping systems. The technique developed utilized lap-shear plaques to predia performance in the pipe joint systems. Results indicate extreme sensitivity to minor variations in preparation. 

Lap Shear Strength (LSS) - A form of adhesive bond strength measured by pulling apart, in tension, two overlapped, bonded strips of material. One of the most commonly quoted mechanical properties of adhesives. Unfortunately the precise details of the adherends and conditions used for the test also have a great effect on the results obtained. 

The interaction of two substrates, the bond strength of adhesives are frequently measured by the peel test [76]. The results can often be related to the reversible work of adhesion. Due to its physical nature such a measurement is impossible to carry out for particulate filled polymers. Even interfacial shear strength widely applied for the characterization of matrix/fiber adhesion cannot be used in particulate filled polymers. Interfacial adhesion of the components is usually deduced indirectly from the mechanical properties of composites with the help of models describing composition dependence. Such models must also take into account interfacial interactions. 

Although important for structural adhesive bonds, fracture mechanics is not as critical for non-structural low load-bearing adhesives as used in most electronic modules. For the most part, passing minimum specification requirements for peel and tensile strengths both at ambient conditions and accelerated test conditions are sufficient. However, computer-simulated modeling and reliability analysis have been used for evaluating electrically conductive adhesives as used in electronics assembly. ... 

The tensile strength and the elongation-at-break of the polymer films were measured according to EN ISO 527 [22], Mechanical tests were performed on the adhesive joints as described in the standard [8] by adhesively bonding two beech wood specimens using a pneumatic press. In particular, density, moisture content, dimensions, thickness and fabrication conditions are specified in the specific standards. 

---