“…Fischer and Puderbach (1969) found little difference in annealing at atmospheric pressure in a temperature range up to 220°C and a pressure up to 4.2 kb (the sample was drawn to 15 χ at 70°C). Similarly, Zubov et al (1972) saw little increase in crystal dimensions ( L 0 0 2 = 300 A , L l l0 = 130 Α , ρ = 0.968, X-ray long period 350 A , drawn 16 χ at 95°C at 10 mm/min) on annealing for 2 hr at up to 250°C at 7 kb. The latter authors did notice, however, an increasing change of the orthorhombic polyethylene to the monoclinic crystal form II (see Table II.9).…”