Relation between Drawing Temperature and Critical Necking Tension on Zone-drawing for Poly(methyl methacrylate) Films

Abstract

The relation between the drawing temperature (Td) and the critical necking tension (crc) has been investigated for amorphous and unoriented poly(methyl methacrylate) (PMMA) films. The σc, defined as the minimum tension causing a necking at a given Td, increased with a decrease in Td in the temperature range of 80°C to 132°C. It was found that the temperature difference between Fg (110.4°C) and Td was proportional to the σc. The relation is represented by the following equation: σc=C(Tg-Td) where C was 0.490 MPa/°C, which is close to that of poly(ether ether ketone) (PEEK) and that of poly (ethylene terephthalate) (PET), but is almost a half of that of polyvinyl chloride) (PVC). The draw ratios of the films zone-drawn at temperatures below Tg were higher than those of films above Tg. The negative birefringence increased with decreasing Td, and that of the film drawn at Td = 80°C was-16 × 10-4. The film drawn at Td= 132°C was almost isotropic. © 1994, The Society of Polymer Science, Japan. All rights reserved.