THE FUSION BEHAVIOUR OF UNPLASTICISED POLYVINYL CHLORIDE: EFFECTS OF PROCESSING AND FORMULATION
THE FUSION BEHAVIOUR OF UNPLASTICISED POLYVINYL CHLORIDE: EFFECTS OF PROCESSING AND FORMULATION
| dc.contributor.author | OGABA, PHILIP OBANDE | |
| dc.date.accessioned | 2014-10-14T08:22:50Z | |
| dc.date.available | 2014-10-14T08:22:50Z | |
| dc.date.issued | 1984-08 | |
| dc.description | A Doctoral Thesis submitted in partial fulfillment of the requirements for the award of Doctor of Philosophy of Loughborough University of Technology September, 1984 Supervisors : M. Gilbert, Ph.D., FPRI, MRSC, C Chem. Institute of Polymer Technology D.E. Marshall, Ph.D., MIP. Institute of Polymer Technology | en_US |
| dc.description.abstract | The fusion behaviour of commercial grade PVC has been studied by capillary rheometry and thermal analysis for twin-screw extruded rigid formulations. The role of shear in fusion was also investigated by extrusion at different rates and by compression moulding. Aspects discussed include thermodynamic fusion (melting) and gelation (network formation). The former is measured by thermal analysis and the latter by rheometry. Fusion is dictated primarily by the level of heat generated during processing while gelation depends both on the equipment shear regime and on formulation. In the molecular weight range studied, M W = 6.0 - 10.0 x 104 g/mol, fusion level is inversely related to M W at a specific processing temperature, but the maximum fusion level attainable within temperature limits is largely independent of molecular weight. At a given processing temperature below 200°C impact strength (IS) of notched Izod samples is linearly related to the extrusion (shear) rate; above 200°C, however, little change is observed. The IS of samples processed at different temperatures, keeping extrusion rate constant, goes through a maximum, but this depends on the temperature range,the shear level, and the formulation. From the results of solvent sorption, density, and wide angle x-ray diffraction, an overall decrease is observed in the level of order left in the processed material with increasing processing temperature. From a mathematical model proposed for the fusion behaviour percentage fusion is shown to be equivalent to the degree of crystallinity. The maximum % fusion observed, about 8%, corresponds to the crystalline level of the unprocessed powder. Based on this model activation energies of 1.0 kJ/mol and 2.2 kJ/mol are obtained for the fusion of the relevant morphological units. | en_US |
| dc.identifier.uri | http://hdl.handle.net/123456789/5480 | |
| dc.language.iso | en | en_US |
| dc.subject | FUSION, | en_US |
| dc.subject | UNPLASTICISED, | en_US |
| dc.subject | POLYVINYL, | en_US |
| dc.subject | CHLORIDE:, | en_US |
| dc.subject | FORMULATION | en_US |
| dc.title | THE FUSION BEHAVIOUR OF UNPLASTICISED POLYVINYL CHLORIDE: EFFECTS OF PROCESSING AND FORMULATION | en_US |
| dc.type | Thesis | en_US |