Block copolymers of aromatic polyamides have been synthesized. The polymers contain stiff, liquid crystal forming blocks and flexible blocks. A series of polymers with differing lengths of the flexible block have been prepared. The polymers have been spun into fibres from liquid crystalline solutions and the properties of as spun and heat treated (500 and 370°C) fibres have been determined. The incorporation of flexible blocks in the stiff polymer resulted in a decrease in Young's modulus and tensile strength while the elongation at break was largely unaffected. The heat treatment resulted in an increase in the Young's modulus of the fibre. The fibre containing the longest flexible block became brittle and stiff towards bending upon heat treatment. The results are discussed in terms of the influence of the block copolymer structure on the fibre morphology.
Посилання на статтю:
Preparation and properties of block copolyamide fibres / Bertil Helgee* and Per Flodin // Polymer. – 1992. – Vol 33. – P. 3616-3620.