Temperature change for polymer films irradiated with incandescent lamp.

The heat absorption by polymer films continuously irradiated with an incandescent lamp was investigated by measuring rates of change in temperature and the equilibrium temperature of the film for bare and backed films. The presence of infrared active groups in the structural units, the film thick ness and the degree of crystallinity contributed to the increase in the equilibrium temperature and the rate of temperature rise. This increase was greater for backed films. Polyethylene films containing a small amount of carbon black had much greater capacity for absorbing thermic rays and attained higher equilib rium temperatures.