A strip of elastomer 1 cm ¥ 1 cm ¥ 10 cm is stretched to 25-cm length at
25°C, a stress of 1.5 ¥ 107 dynes/cm2 being required.
(a) Assuming a tetrafunctional cross-linking mode, how many moles of
network chains are there per cubic centimeter?
(b) What stress is required to stretch the sample to only 15 cm, at 25°C?
(c) What stress is required to stretch the sample to 25-cm length at 100°C?