Vidya, Francis; Dr. Eby Thomas, Thachil(Cochin University of Science and Technology, November , 2012)
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Abstract:
LLDPE was blended with poly (vinyl alcohol) and mechanical, thermal, spectroscopic properties and biodegradability were investigated. The biodegradability of LLDPE/PVA blends has been studied in two environments, viz. (1) a culture medium containing Vibrio sp. and (2) a soil environment over a
period of 15 weeks. Nanoanatase having photo catalytic activity was synthesized by hydrothermal method using titanium-iso-propoxide. The synthesized TiO2 was characterized by X-Ray diffraction (XRD), BET studies, FTIR studies and scanning electron microscopy (SEM). The crystallite size of titania was calculated to be ≈ 6nm from the XRD results and the surface area was found to be about
310m2/g by BET method. SEM shows that nanoanatase particles prepared by this method are spherical in shape. Linear low density polyethylene films containing polyvinyl alcohol and a pro-oxidant (TiO2 or cobalt stearate with or without vegetable oil) were prepared. The films were then subjected to natural weathering and UV exposure followed by biodegradation in culture medium as well as in soil environment. The degradation was monitored by mechanical property measurements, thermal studies, rate of weight loss, FTIR and SEM studies. Higher weight loss, texture change and greater increments in carbonyl index values were observed in samples containing cobalt stearate and vegetable oil. The
present study demonstrates that the combination of LLDPE/PVA blends with (I) nanoanatase/vegetable oil and (ii) cobalt stearate/vegetable oil leads to extensive photodegradation. These samples show substantial degradation when subsequent exposure to Vibrio sp. is made. Thus a combined photodegradation and biodegradation process is a promising step towards obtaining a biodegradable
grade of LLDPE.
Description:
Department of Polymer Science and Rubber Technology, Cochin University of Science and Technology
Gisha Elizabeth, Luckachan; Dr. C K S Pillai(Regional Research Laboratory (CSIR), May , 2006)
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Abstract:
Biodegradable polymers have opened an emerging area of great interest
because they are the ultimate solution for the disposal problems of synthetic
polymers used for short time applications in the environmental and biomedical
field. The biodegradable polymers available until recently have a number of
limitations in terms of strength and dimensional stability. Most of them have
processing problems and are also very expensive. Recent developments in
biodegradable polymers show that monomers and polymers obtained from
renewable resources are important owing to their inherent biodegradability,
biocompatibility and easy availability. The present study is, therefore, mostly
concemed with the utilization of renewable resources by effecting chemical
modification/copolymerization on existing synthetic polymers/natural polymers
for introducing better biodegradability and material properties.The thesis describes multiple approaches in the design of new
biodegradable polymers: (1) Chemical modification of an existing nonbiodegradable
polymer, polyethylene, by anchoring monosaccharides after
functionalization to introduce biodegradability. (2) Copolymerization of an
existing biodegradable polymer, polylactide, with suitable monomers and/or
polymers to tailor their properties to suit the emerging requirements such as
(2a) graft copolymerization of lactide onto chitosan to get controlled solvation
and biodegradability and (2b) copolymerization of polylactide with cycloaliphatic amide segments to improve upon the thermal properties and
processability.