DEGRADATION OF SOME POLYMER BLENDS
DEGRADATION OF SOME POLYMER BLENDS
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Date
1983-03
Authors
AVOAJA, ANTHONY GODWIN IHEM
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Abstract
Blends of PVA with PVC, PMMA and PS and PS/PMMA, that
cover the entire compositional range have been subjected to
outdoor weathering, thermal oxidation and ultraviolet irradiation.
With the application of infra-red technique it was possible to
detect any structural changes taking place. With the aid of
Instron testing instrument it was possible to find out the
mechanical modifications that have taken place.
The present work investigates the effect of a second
polymer on the weathorability of another. The author has
observed that in all the cases investigated there was interaction
between the dissimilar molecular chains, at least at
the phase boundaries, for the two-phase systems. These
interactions which may be intermolecular or intramolecular
are observed in most cases to have deliterous effects on the
structural stability and mechanical properties of the polymers.
In a few cases, the interaction reduced the vulnerability of
either or both homopolymers to weathering.
From the studies it has been observed that PMMA
stabilises PVA against outdoor weathering and oven aging,
while PVA stabilizes PMMA against ultraviolet degradation.
For the PVA/PVC blends general deterioration of property was
observed on blending with PVA destabilizing PVC and vice
versa, with the effect of PVC on PVA being more pronounced.
For the PVA/PS blends, although rigidity was observed to
increase with increase in PS in the blends, the presence of
PVA was observed to cause general deterioration of mechanical
properties, with a minimum in tensile strength, modulus and
percentage elongation at 30% PVA in the blends. Vulnerability
to thermal degradation was also observed to increase with
increase in PVA in the blend. PMMA was observed to destabilize
PS to outdoor weathering and on thermal aging all the blends
had lower induction periods than the homopolymers.
From morphological studies, PVA/PMMA and PS/PMMA were
found to be compatible while PVA/PVC and PVA/PS were incompatible
Description
A THESIS SUBMITTED TO THE POSTGRADUATE SCHOOL,
AHMADU BELLO UNIVERSITY, IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
M.Sc. (POLYMER SCIENCE AND TECHNOLOGY)
FACULTY OF SCIENCE
AHMADU BELLO UNIVERSITY, ZARIA
MARCH, 1983
Keywords
DEGRADATION,, POLYMER,, BLENDS.