| Summary: | This study describes the preparation and characterization of single polymer composites of
poly(methyl methacrylate) (PMMA) reinforced with electrospun nanofibres. These single
polymer composites, which refer to composites in which both the matrix and reinforcement
are from the same polymer, have specific economic and ecological advantages and can be
recycled. The nanofibres used as reinforcements in this study were produced by an
electrospinning process. The interest in the nanofibres over traditional fibres was motivated
by the large specific surface area to volume ratio, the smaller diameter and superior
mechanical properties.
The effect of the electrospinning parameters on the morphology and diameters of the
electrospun high molecular weight PMMA (PMMAhigh) was investigated in order to obtain
suitable diameters for the reinforcing fibres. The electrospinning parameters investigated
were the polymer solution concentration, applied voltage and spinning distance. The results
showed that the polymer solution concentration influences the diameter of the electrospun
nanofibres more than the spinning voltage and the spinning distance. Furthermore, SEM
analysis of the PMMAhigh nanofibres showed that the fibres had a smooth regular and
cylindrical morphology with no beads and junctions.
Effects of the processing temperature on the preparation of the single polymer composites of
PMMA via a film stacking method were investigated. PMMAhigh nanofibres, with diameters
ranging from 400-650 nm, were used as the reinforcement and a low molecular weight
PMMA (PMMAlow) as the matrix. The results indicated that a processing temperature of 150
°C yielded the best composite with distinguishable physical phases and adequate melting of
the matrix material.
The effects of the different nanofibre diameters, fibre loading and processing temperature on
the thermo-mechanical properties of the PMMA SPCs were investigated. Dynamic
mechanical analysis showed a pronounced improvement in the storage moduli, loss moduli
and tan δ of the composites compared to the matrix. This behaviour is the result of a positive
reinforcing effect of the PMMAhigh nanofibres. The possibility of using the PMMAhigh
nanofibres to improve the thermal stability of the PMMA SPCs was also investigated. The results indicated that the thermal stability of the neat PMMAlow matrix is unaffected by the
composites formation. This is probably the result of the lower thermal stability of the
PMMAhigh nanofibres. Characterization of the mechanical properties of the PMMA single polymer composites
revealed that the flexural and impact properties improved upon composite formation whilst
the tensile properties remained unchanged.
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