Dynamic mechanical analysis (DMA) or dynamic mechanical thermal analysis (DMTA)
DMA is a technique used to study and characterise materials. It is most especially useful for observing the viscoelastic nature of polymers. An oscillating force is applied to a sample of material, the resulting displacement of the sample is measured. From this the sample stiffness can be determined, and the sample modulus can be calculated. By measuring the time lag in the displacement compared to the applied force it is possible to determine the damping properties of the material. Viscoelastic materials such as polymers typically exist in two distinct states. They exhibit the properties of a glass (high modulus) at low temperatures and those of a rubber (low modulus) at higher temperatures. By scanning the temperature during a DMA experiment the change of state can be observed and the glass transition temperature (Tg) can be determined.
DMTA has the ability to give basic information on polymeric structures, which is an advantage over other test methods for adhesion.
The primary result was that the interaction as measured with DMTA between wood and polymers with high interaction and adhesion to wood showed a decrease in glass transition temperature (Tg) as compared to the Tg of the pure polymer material.
This thesis shows that DMTA is an interesting method to obtain a basic understanding of adhesion phenomena and should be of interest for manufacturers of glues and paints and lacquers, and especially for thermoplastic adhesives.
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