A variety of polymer blend systems are examined by positron annihilation lifetime spectroscopy (PALS). The third lifetime component of the PALS spectra is attributed to the pick-off annihilation in free volume sites present in the amorphous regions of the polymer, at defects in crystals, and at interfaces. An analysis method was used to remove the contributions from crystalline defects, allowing the examination of the free volume behaviour in the amorphous and interfacial regions in polymer blends as a function of blend composition, compatibiliser content, and thermal history. Blend composition altered free volume in a manner dependent on the level of the miscibility of the polymers. Free volume varied in a manner consistent with fracture toughness as a function of compatibiliser concentration in an immiscible blend. Thermal history was varied in a semicrystalline, miscible blend in order to increase blend crystallinity and place an increasing constraint on the miscible, amorphous regions. The stress transfer across the crystal/amorphous interface was evident in the glass transition and free volume behaviour of the blends.
|Number of pages||6|
|Journal||Materials Science Forum|
|Publication status||Published - 1 Jan 1995|
|Event||Proceedings of the 2nd International Conference on the Role of Interfaces in Advanced Materials Design, Processing and Performance - Ballarat, Aust|
Duration: 1 Nov 1993 → 5 Nov 1993