Posted by Karen on July 08, 2004 at 15:20:50:

For the sake of long term service life prediction, we performed Heat Deflection Temperature under Load (DTUL) experiment on thermoset vinyl epoxy composite by putting the samples in a bath with a three-point bend fixture, and then expose the sample to a load. Then, temperature was increased at a constant rate of 2 degrees Celsius per minute, keeping the system pressure constant.

Although processing conditions of the material is of course an important ageing factor, do you think Heat Deflection Temperature (HDT) is really a good measure for the long term performance at elevated temperature?

Moreover, are you familiar with the exact the quantitative influence of post curing time and temperature on the heat deflection temperature.

Last but not least: if we subject a solid rod to tension we pull the atoms further apart; if we compress it we push them closer together. The interatomic forces resist these changes and if the distortions are not too large, the body will return to its original dimesnions when the external pressure, shear or tensions forces are removed;the deformations are then called elastic. But do you have any idea of the effect of hydrostatic pressure combine with surface liquid absorption/diffusion on the tensile strength and Poisson's ratio of a material?

Thanks

Karen

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