Investigating the competitiveness of natural rubber latex-films as a potential substitute for common thin-film plastic packaging materials

A thesis submitted to the Department of Chemical and Process Engineering for the MSc in Polymer TechnologyThis report is based on an Industrial research, performed as an initiative effort, to introduce dip-coated Natural Rubber (NR) latex films, to compete with some common thin-film, flexible, plastic, packaging materials. While identifying some of the most sensitive global issues associated with such plastic packaging materials, Natural rubber latex was qualified in terms of many of its unique properties, essentially being a renewable resource. Sample production and testing were carried out at an industrial research and development facility where a comparative analysis was made to establish relative mechanical performance of rubber against Polyvinylchloride (PVC), Polypropylene (PP), and Polyethylene (PE) films. It was shown that the natural rubber films being produced exhibited comparable performance levels in terms of tensile strength and resistance against abrasion, while the films over-performed the tested thermoplastic films with respect to percentage elongation at break, resistance against abrasion, tear, blade-cut, and puncture, including resistance against macro-level water and air leakage. Accordingly, it was suggested that Natural rubber (NR) films having a minimut? thickness of 0.3 mm, possessed potential prospects as a competitor for the selected categories of Polyethylene, Polypropylene, and Polyvinylchloride films, having a thickness range of 0.04mm to 0.11mm, in terms of mechanical performance criteria being considered

Impact of exposure to conflict, tsunami and mental disorders on school absenteeism: findings from a national sample of Sri Lankan children aged 12–17 years

BACKGROUND: Armed conflicts and natural disasters are common. Millions of people, including children are killed, injured, disabled and displaced as a result. The effects of conflict and natural disaster on mental health, especially of children are well established but effects on education have received less attention. This study investigated associations between conflict and/or tsunami exposure in Sri Lanka and their associations with absenteeism in a national sample of school children. METHODS: A cross-sectional survey was conducted in 2006–7 among 1,505 randomly selected school children aged 12–17 years attending government schools in 17 districts. The hypotheses were that absenteeism would be more common in children previously affected by conflict or the 2004 tsunami and that at least part of this effect would be accounted for by mental disorders. Survey information included socio-demographic, conflict and tsunami exposure, mental health status (Strengths and Difficulties Questionnaire) and information on absenteeism (defined as 20% or greater non-attendance over one year). RESULTS: The total sample of consisted of 1,505 students aged 12–17 years with a mean age of 13.7 years. 120 children reported at least one conflict exposure and 65 reported at least one tsunami exposure while only 15 reported exposure to both conflict and tsunami. Prevalence of emotional disorder caseness was 2.7%, conduct disorder caseness 5.8%, hyperactivity disorder caseness 0.6%, and 8.5% were identified as having any psychiatric disorder. Absenteeism was present in 26.8%. Overall, previous exposure to tsunami (OR 2.29 95% CI 1.36-3.84) was significantly associated with absenteeism whereas exposure to conflict was not (OR 1.32 95% CI 0.88-1.97), although some specific conflict-related exposures were significant risk factors. Mental disorder was strongly associated with absenteeism but did not account for its association with tsunami or conflict exposure. CONCLUSIONS: Exposure to traumatic events may have a detrimental effect on subsequent school attendance. This may give rise to perpetuating socioeconomic inequality and needs further research to inform policy and intervention