Solubility of a UV-stabiliser in some poly(ester-block-ether) copolymers

The solubility of a typical UV-absorbing stabiliser has been measured in a series of poly(ester-block-ether)s copolymers (PEBE) with different ratios of hard and soft blocks. The solubility is higher in the PEBEs than in poly propylene and increases with the amount of polyether in the PEBE. The compo sition dependence suggests that the additive is at least ten times more sol uble in the soft polyether phase than in the semi-crystalline hard phase. A thermodynamic analysis in terms of regular solution theory shows that incr eased solubility is due to better compatibility of the additive with the po lyether than with PP, mainly due to much more favourable heat of mixing. (C ) 2000 Elsevier Science Ltd. All rights reserved.