Influence of moisture on the time and temperature dependent properties of polymer systems

Abstract

The use of temperature and time dependent material parameters is state-of-the-art in mechanical engineering. An advanced measurement method for the determination of moisture dependent parameters for micro and nano scale samples was developed. In combination with FE-analysis, this tool (involving time, temperature, and humidity) ensures a sure deployability. The present paper deals with the influence of the moisture absorption oil the time and temperature dependent properties of epoxy systems. These thermosetting polymers have strong time and temperature dependent mechanical properties. It is ail excellent material for understanding moisture induced thermo mechanical behaviour. The influence of humidity on the materials behaviour shows that the humidity diffusion does not only effect a shift in the glass transition temperature and a reduction in the modulus, but also influences the visco elastic properties significantly. The moisture-dependent properties are analyzed by novel experimental procedures. It was found that for a lifetime model the relaxation behaviour as a function of temperature over time and moisture has a significant influence, which increases not only with temperature but also with moisture concentration. The cause of variant properties is the free volume and /or polarity of the structure. The combination of several Such factors of different materials parameters (moisture concentration hygroscopic swelling, and diffusion coefficient) and their interrelated influences makes ail important contribution to mechanical reliability analysis

Simultaneous Visualization of Phase Separation and Crystallization in PHB/PLLA Blends with In Situ ATR-FTIR Spectroscopic Imaging

“…Since moisture can affect both physical and chemical properties of polymers, PHB and PLLA were placed in a vacuum desiccator at ambient temperature to remove the moisture inside . After 24 h, these dried polymers were dissolved in a suitable solvent: chloroform with a weight ratio of 50:50.…”

Contacting electronics to fabric circuits with nonconductive adhesive bonding

“…In contrast, at application temperatures as high as 125°C or 150°C the material relaxes quickly in the order of hours or seconds, respectively. (Linz, 2011) ms sec h d m a 10 (Linz, 2011) The influence of the humidity could be determined as described by Walter et al (2009). Yet, the effort was not made as the data on the dry condition was considered sufficient.…”