title: The Effect of Heat Treatment on the Structure and Properties of Hemp/PLA Composites

authors: Jayaraman, Jeevan

subjects: PLA

abstract: This project focuses on bio-derived composites made from poly(lactic acid) (PLA) and hemp as well as the influence of PLA crystallinity on material properties. 
It is known that crystallinity can occur as spherulites within a polymer matrix bulk and as transcrystallinity on fibre surfaces in thermoplastic matrix composites. In addition, thermal history is known to influence the degree of crystallinity of polymer materials. The aim of this project was to study the effect of heat treatment or  annealing  on crystallinity and the influence of this on properties of hemp/PLA composites. 
	Composites were observed to become more opaque during heat treatment and increased crystallinity after heat treatment was seen using optical microscopy. XRD and DSC results showed that crystallinity was much higher for composites than PLA, supporting the fibre acting as a nucleating agent. There was no apparent change to tensile strength with increased heat treatment for PLA, however, for composite samples, increased heat treatment led to a small reduction in average tensile strength. Although there was no discernable trend for change of fracture toughness with increased crystallinity for PLA, it decreased for composite materials. It appears that the increased crystallinity present in the composite in combination with increased stress concentration due to the presence of fibres is reducing composite toughness as well as leading to premature failure in tensile tests due to PLA brittleness explaining lower strengths for composites. DMTA suggests that increase in crystallinity contributes to thermal stability of the composite.

text: The Effect of Heat Treatment on the Structure and Properties of Hemp/PLA Composites This project focuses on bio-derived composites made from poly(lactic acid) (PLA) and hemp as well as the influence of PLA crystallinity on material properties. 
It is known that crystallinity can occur as spherulites within a polymer matrix bulk and as transcrystallinity on fibre surfaces in thermoplastic matrix composites. In addition, thermal history is known to influence the degree of crystallinity of polymer materials. The aim of this project was to study the effect of heat treatment or  annealing  on crystallinity and the influence of this on properties of hemp/PLA composites. 
	Composites were observed to become more opaque during heat treatment and increased crystallinity after heat treatment was seen using optical microscopy. XRD and DSC results showed that crystallinity was much higher for composites than PLA, supporting the fibre acting as a nucleating agent. There was no apparent change to tensile strength with increased heat treatment for PLA, however, for composite samples, increased heat treatment led to a small reduction in average tensile strength. Although there was no discernable trend for change of fracture toughness with increased crystallinity for PLA, it decreased for composite materials. It appears that the increased crystallinity present in the composite in combination with increased stress concentration due to the presence of fibres is reducing composite toughness as well as leading to premature failure in tensile tests due to PLA brittleness explaining lower strengths for composites. DMTA suggests that increase in crystallinity contributes to thermal stability of the composite.

year: 2010

title: Editorial

authors: Martin, Rose

abstract: Welcome to the fourth volume of Dance Research Aotearoa. We are excited to share with you this unique collection of articles that explore topics connected to community dance, social justice and social transformation. The papers published within this volume are drawn from distinctive dance events held in Aotearoa in 2015—the Dance and Social Justice Symposia held in Hamilton on 3 October (hosted by The University of Waikato), and in Auckland on 5 November (hosted by the University of Auckland), along with The Moving Communities International Conference on Community Dance held in Dunedin in November 2015 (hosted by The University of Otago). Alison East provides an overview of the Moving Communities conference in her introductory comments in this volume, entitled Dance in/for/with/as/Community: Re-defining community dance in 2015–16. East begins with a significant question about how dance can play a meaningful role in fostering healthy communities. This question is explored in the articles in this volume.

text: Editorial Welcome to the fourth volume of Dance Research Aotearoa. We are excited to share with you this unique collection of articles that explore topics connected to community dance, social justice and social transformation. The papers published within this volume are drawn from distinctive dance events held in Aotearoa in 2015—the Dance and Social Justice Symposia held in Hamilton on 3 October (hosted by The University of Waikato), and in Auckland on 5 November (hosted by the University of Auckland), along with The Moving Communities International Conference on Community Dance held in Dunedin in November 2015 (hosted by The University of Otago). Alison East provides an overview of the Moving Communities conference in her introductory comments in this volume, entitled Dance in/for/with/as/Community: Re-defining community dance in 2015–16. East begins with a significant question about how dance can play a meaningful role in fostering healthy communities. This question is explored in the articles in this volume.

year: 2016

title: Gendered geographies of resistance, resilience and reworking in Aotearoa feminist geography scholarship

authors: Adams-Hutcheson, Gail

abstract: Aotearoa New Zealand feminist geographies involve alliances of connected and vibrant researchers who pay close attention to the politics of knowledge production, power, intersectionality and decolonisation. Safe spaces to speak and write together have been nurtured over time ‘down under’ due to a collective politics of care and mentoring. This special issue demonstrates the strength of collective thinking on resistance, resilience and reworking contemporary geographical practice in Aotearoa. The four empirically based and theoretically informed articles develop new thinking about resistance to colonialism, patriarchy, racism, metricisation and oppression. These critical articles contribute to feminist geographical knowledges both locally and globally.

text: Gendered geographies of resistance, resilience and reworking in Aotearoa feminist geography scholarship Aotearoa New Zealand feminist geographies involve alliances of connected and vibrant researchers who pay close attention to the politics of knowledge production, power, intersectionality and decolonisation. Safe spaces to speak and write together have been nurtured over time ‘down under’ due to a collective politics of care and mentoring. This special issue demonstrates the strength of collective thinking on resistance, resilience and reworking contemporary geographical practice in Aotearoa. The four empirically based and theoretically informed articles develop new thinking about resistance to colonialism, patriarchy, racism, metricisation and oppression. These critical articles contribute to feminist geographical knowledges both locally and globally.

year: 2022-11-22