Thesis-1994-Martin.pdf (6.45 MB)
Compatibilisation of polysulphones/polyester blends
thesis
posted on 2013-03-04, 14:42 authored by Lee MartinTernary blends comprising Polysulphones [Polyethersulphone (PES) and Polysulphone
(PSO)], the Polyhydroxyether of bisphenol-A (Phenoxy), and Polyesters [Poly( ethylene
terephthlate) (PET) and Poly(butylene terephthlate) (PBT)] have been studied
particularly with the aim in mind of elucidating the factors determining their miscibility
and morphology. Binary and ternary combinations, including equivalent systems based
on a butylene terephthlate-tetramethylene oxide block copolymer (PBT-TMO), were
prepared from solution and by mixing in the melt state using both an internal mixer and a
twin screw extruder.
Scanning electron microscopy was employed to examme the morphology of these
blends. A co-continuous, (interpenetrating), dual-phase morphology was displayed by
both the PSO/PBT and PSO/PBT-TMO (70/30) combinations. The compatibility was
further increased by the addition of Phenoxy, which was evidenced by the formation of a
very fine dispersion of the two phases for both PSO/Phenoxy/PBT and
PSO/Phenoxy/PBT-TMO blends, in the weight ratio of (60/15/25). A lower level of
compatibility was displayed by the equivalent blends based on PES and PET, as a
matrix/dispersed particle type of morpholgy was usually observed. Differential thermal analysis and dynamic mechanical analysis measurements were also
employed to ascertain the level of miscibility in these systems. A single composition
dependent glass transition temperature was displayed by the binary PBT/Phenoxy and
PBT-TMO/Phenoxy melt blends, and the binary PES/Phenoxy and _PSO/Phenoxy
solution blends. The remaining blends displayed two separate glass transition
temperatures that were often broader and closer together than those of the
homopolymers. This effect was more significant for blends containing the Phenoxy
compatibiliser, confirming that these systems are semi-miscible.
Solvent resistance measurements were made on 500μm thick extruded sheets by
measuring the time to failure at stress levels corresponding to 30% and 50% of the
tensile strength. The blends displaying a matrix/dispersed particle type of morphology
revealed poor solvent resistance and mechanical properties. The blends displaying a cocontinuous
interpenetrating dual-phase morphology on the other hand displayed a much
higher solvent resistance and enhanced mechanical properties.
History
School
- Aeronautical, Automotive, Chemical and Materials Engineering
Department
- Materials
Publisher
© L. MartinPublication date
1994Notes
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.EThOS Persistent ID
uk.bl.ethos.283127Language
- en