Nanocomposites have received a great deal of attention in recent years; particularly polymer layered silicate nanocomposites such as montmorillonite, where the surface to volume ratio is exceptionally high. As a result of their ultrafine phase dimensions, these layered silicate nanocomposites possess unique properties typically not shared by more conventional microcomposites and, therefore, offer new technology and business opportunities. However, despite the attention, the influence of compatibilisers on the nanocomposites is not well understood; more critically, the literature exposes a large degree of disagreement as to the required compatibiliser type for optimal function. This study examines the effect of Maleic Anhydride grafted HDPE compatibilisers, with differing MFls and grafting contents, on the mechanical, thermal an.d rheological properties of HDPE. The materials were compounded in a twin screw extruder before being compression moulded into plaques for characterisation and analysis; this consisted of structural analysis utilising XRD and tensile testing; thermal and rheological characterisation using power compensated DSC, DMTA and a rotational rheometer. The results confirm organo-modification of MMT as sufficient in producing a miscible polymer system; however addition of compatibiliser is best. In an unfilled system, the incorporation of MAH groups cause axis distortion and rearrangement of chain conformation and lattice structure, crosslin king and increase RAF. With the addition of MMT, the MAH groups preferentially interact with the clay changing the crystal type to transcrystalline layers, lowering the Tg whilst simultaneously increasing the modulus. The most effective compatibilisers have a characteristic enabling a more dominant exfoliation mechanism. Intercalated nanocomposites presented the more improved systems, with 4:1 and 5:1, plus 5% clay, being the optimal due to crystallisation between layers. Changes in MFI and grafting are a complicated matrix but higher mobility and grafting is preferred: as opportunity for interaction increases, the likelihood of formation of nanocomposites, and improvement in material properties, increases.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:679044 |
| Date | January 2014 |
| Creators | Lutton, R. |
| Publisher | Queen's University Belfast |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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