Hygroscopic Material


		Most people understand that materials expand and contract with a rise and fall in temperature but many do not understand that with hygroscopic materials there is a greater rate of expansion and contraction with a rise and fall in humidification level. A dry atmosphere can cause textiles, carpet, wood, paper leather plastics, etc. to shrink, harden crack spoil and loose weight. Weight loss can be a particular problem when produce is sold by the kg.

Futniture, for example, would show the typical results of being in an atmosphere where the humidity has gone from the extremes of damp to extremes of dry. Panels could split and joints break. Interestingly, the joints of most items of wooden furniture are more susceptible to damage as the glue used to fix them is likely to be hygroscopic in its own right and more prone to failure than the acutal material of construction.

John Anderberg

Bricksite.com