단열재료
Polystyrene (PS)
The temperature-dependent change in volume of polystyrene can be measured with a dilatometer using a special cylinder as a sample holder.
Before the 1st heating, the sample was aged below Glass Transition TemperatureThe glass transition is one of the most important properties of amorphous and semi-crystalline materials, e.g., inorganic glasses, amorphous metals, polymers, pharmaceuticals and food ingredients, etc., and describes the temperature region where the mechanical properties of the materials change from hard and brittle to more soft, deformable or rubbery.glass transition temperature (Tg); the 2nd heating was conducted on the same sample after controlled cooling. The volume RelaxationRelaxation은 고무에 일정한 변형률이 가해지면, 변형률을 유지하기 위해 필요한 힘은 일정하지는 않지만 시간에 따라 감소합니다. 이러한 특성을 ‘응력 완화’라고 부릅니다. 응력완화의 원인이 되는 과정은 물리적 또는 화학적 그리고 정상적인 조건 하에, 둘 다 동시에 일어날 수 있습니다. relaxation for the 1st heating is clearly visible at the Tg, as is the change in slope at the Tg for the 2nd heating. (measurement with DIL 402 C)