{"id":{"repo_id":"london-metro","oai_identifier":"oai:repository.londonmet.ac.uk:3298"},"canonical_url":"https://search.dev.ndltd.org/etd/london-metro/oai:repository.londonmet.ac.uk:3298","repository":{"repo_id":"london-metro","name":"London Metropolitan University","base_url":"https://repository.londonmet.ac.uk/cgi/oai2"},"display":{"title":"An investigation into the polyethylene extrudates produced by simultaneous orientation and high temperature quenching","abstract":"An apparatus was designed and constructed to allow a molten polymer extrudate under tension - or draw-down - to pass through a volume of liquid metal alloy in order that the extrudate would rapidly reach the temperature of the metal and be fully quenched on leaving the medium. The temperature of the medium could be controlled to an accuracy of +/- 0.5°C and the molten extrudates could be subjected to a wide range of draw-downs whilst maintaining a continuous production of extrudate. High density polyethylene (HOPE) extrudates were prepared from three dies - circular, strip and flat-film - at a range of liquid metal alloy temperatures (111 - 123°C) and over a wide range of draw-downs. The effect of processing on the HOPE extrudates was analysed by tensile testing, cyclic strain recovery, shrinkage testing, density measurements and annealing in air and liquid metal at 117°C. It was found that the level of draw-down and the temperature of the quenching medium had a profound effect upon the resultant properties of the extrudate. Extrudates prepared using a low level of orientation and low bath temperature are similar to those quenched in air, i.e. having a pronounced yield point, whereas those prepared using a high level of orientation and a high bath temperature exhibited properties similar to those of amorphous samples, i.e. high modulus and low extension at break. However, if the extrudate remains in the bath longer than is necessary to quench it, this effect is reversed. A possible mechanism was proposed to explain the relationship between the values of the processing parameters used, the morphology of the resultant HDPE extrudates and their properties.","abstract_html":"An apparatus was designed and constructed to allow a molten polymer extrudate under tension - or draw-down - to pass through a volume of liquid metal alloy in order that the extrudate would rapidly reach the temperature of the metal and be fully quenched on leaving the medium. The temperature of the medium could be controlled to an accuracy of +/- 0.5°C and the molten extrudates could be subjected to a wide range of draw-downs whilst maintaining a continuous production of extrudate. High density polyethylene (HOPE) extrudates were prepared from three dies - circular, strip and flat-film - at a range of liquid metal alloy temperatures (111 - 123°C) and over a wide range of draw-downs. The effect of processing on the HOPE extrudates was analysed by tensile testing, cyclic strain recovery, shrinkage testing, density measurements and annealing in air and liquid metal at 117°C. It was found that the level of draw-down and the temperature of the quenching medium had a profound effect upon the resultant properties of the extrudate. Extrudates prepared using a low level of orientation and low bath temperature are similar to those quenched in air, i.e. having a pronounced yield point, whereas those prepared using a high level of orientation and a high bath temperature exhibited properties similar to those of amorphous samples, i.e. high modulus and low extension at break. However, if the extrudate remains in the bath longer than is necessary to quench it, this effect is reversed. A possible mechanism was proposed to explain the relationship between the values of the processing parameters used, the morphology of the resultant HDPE extrudates and their properties.","abstract_has_math":false,"creators":["Berry, Colin"],"institution":"University of North London","degree_name":"phd","degree_level":"doctoral","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":1993,"date_issued":"1993-03","date_published":"1993-03","updated_at":"2026-07-24T02:54:30Z","subjects":["670 Manufacturing"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier.grantnumber","label":"Dc Identifier Grantnumber","values":["N/A"],"render_values":[{"text":"N/A","href":null,"code":true}]}]},"links":{"outbound_url":null,"outbound_label":null,"outbound_source":null},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.sponsor","label":"Sponsor","values":["London Metropolitan University"]},{"key":"dc:creator","label":"Author","values":["Berry, Colin"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["1993-03"]},{"key":"dc:date.issued","label":"Date","values":["1993-03"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["School of Human Sciences (SHSC)","London School of Polymer Technology"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of North London"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["https://repository.londonmet.ac.uk/3298/"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["doctoral"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["phd"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["670 Manufacturing"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.grantnumber","label":"Dc Identifier Grantnumber","values":["N/A"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://repository.londonmet.ac.uk/3298/1/359297.pdf"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["An apparatus was designed and constructed to allow a molten polymer extrudate under tension - or draw-down - to pass through a volume of liquid metal alloy in order that the extrudate would rapidly reach the temperature of the metal and be fully quenched on leaving the medium. The temperature of the medium could be controlled to an accuracy of +/- 0.5°C and the molten extrudates could be subjected to a wide range of draw-downs whilst maintaining a continuous production of extrudate. High density polyethylene (HOPE) extrudates were prepared from three dies - circular, strip and flat-film - at a range of liquid metal alloy temperatures (111 - 123°C) and over a wide range of draw-downs. The effect of processing on the HOPE extrudates was analysed by tensile testing, cyclic strain recovery, shrinkage testing, density measurements and annealing in air and liquid metal at 117°C. It was found that the level of draw-down and the temperature of the quenching medium had a profound effect upon the resultant properties of the extrudate. Extrudates prepared using a low level of orientation and low bath temperature are similar to those quenched in air, i.e. having a pronounced yield point, whereas those prepared using a high level of orientation and a high bath temperature exhibited properties similar to those of amorphous samples, i.e. high modulus and low extension at break. However, if the extrudate remains in the bath longer than is necessary to quench it, this effect is reversed. A possible mechanism was proposed to explain the relationship between the values of the processing parameters used, the morphology of the resultant HDPE extrudates and their properties."]},{"key":"dc:format","label":"Dc Format","values":["text"]},{"key":"dc:title","label":"Title","values":["An investigation into the polyethylene extrudates produced by simultaneous orientation and high temperature quenching"]}]}],"canonical_facts":{"dc:contributor.sponsor":["London Metropolitan University"],"dc:creator":["Berry, Colin"],"dc:date":["1993-03"],"dc:date.issued":["1993-03"],"dc:description.abstract":["An apparatus was designed and constructed to allow a molten polymer extrudate under tension - or draw-down - to pass through a volume of liquid metal alloy in order that the extrudate would rapidly reach the temperature of the metal and be fully quenched on leaving the medium. The temperature of the medium could be controlled to an accuracy of +/- 0.5°C and the molten extrudates could be subjected to a wide range of draw-downs whilst maintaining a continuous production of extrudate. High density polyethylene (HOPE) extrudates were prepared from three dies - circular, strip and flat-film - at a range of liquid metal alloy temperatures (111 - 123°C) and over a wide range of draw-downs. The effect of processing on the HOPE extrudates was analysed by tensile testing, cyclic strain recovery, shrinkage testing, density measurements and annealing in air and liquid metal at 117°C. It was found that the level of draw-down and the temperature of the quenching medium had a profound effect upon the resultant properties of the extrudate. Extrudates prepared using a low level of orientation and low bath temperature are similar to those quenched in air, i.e. having a pronounced yield point, whereas those prepared using a high level of orientation and a high bath temperature exhibited properties similar to those of amorphous samples, i.e. high modulus and low extension at break. However, if the extrudate remains in the bath longer than is necessary to quench it, this effect is reversed. A possible mechanism was proposed to explain the relationship between the values of the processing parameters used, the morphology of the resultant HDPE extrudates and their properties."],"dc:format":["text"],"dc:identifier.grantnumber":["N/A"],"dc:identifier.uri":["https://repository.londonmet.ac.uk/3298/1/359297.pdf"],"dc:publisher.department":["School of Human Sciences (SHSC)","London School of Polymer Technology"],"dc:publisher.institution":["University of North London"],"dc:relation.isreferencedby":["https://repository.londonmet.ac.uk/3298/"],"dc:subject":["670 Manufacturing"],"dc:title":["An investigation into the polyethylene extrudates produced by simultaneous orientation and high temperature quenching"],"dc:type":["Thesis"],"dc:type.qualificationlevel":["doctoral"],"dc:type.qualificationname":["phd"]},"updated_at":"2026-07-24T02:54:30Z"}