Master of Philosophy (M.Phil.)

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Browsing Master of Philosophy (M.Phil.) by Author "Egodage SM"

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    Characterization of calcium carbonate filled natural rubber - low density polyethylene blends prepared with a titanate coupling agent
    (2019) Sampath WDM; Egodage SM; Edirisinghe DG
    The aim of this study was to develop reactive blends from natural rubber (NR) and low density polyethylene (LDPE) with acceptable physico-mechanical properties. NR and LDPE blends at different blend ratios were produced in a Brabender Plasticorder by melt mixing at a temperature of 150 oC, and rotor speed of 60 rpm. 20 parts per hundred parts of polymer (pphp) calcium carbonate was added as an inorganic filler. Physico-mechanical and chemical properties of the blends and composites were determined according to international standards. Thermal properties were determined using a differential scanning calorimeter. Morphology and structural characteristics were examined by a scanning electron microscope and fourier transform infrared analyzer, respectively. 50/50 NR/LDPE blends were prepared using three vulcanizing systems: sulphur, peroxide and mixture of sulphur and peroxide. NR/LDPE blend prepared with the mixed vulcanizing system showed the highest physicomechanical, chemical, and ageing properties with a fine morphology. A series of simple blends was formulated by varying the LDPE loading from 10 to 90 pphp at 20 pphp intervals. The tensile strength, tear strength, and hardness increased with the increase of LDPE loading, while elongation at break decreased. The continuous phase of blends changed from NR to LDPE above 30 pphp LDPE loading. The optimum tensile and ageing properties were obtained for the composite prepared with 20 pphp calcium carbonate with or without titanate coupling agent (titanate CA) at 30 pphp LDPE loading. Further, 70/30 NR/LDPE composite prepared with 0.7 pphp titanate CA presented the highest physicomechanical, chemical and ageing properties. Furthermore, the performance of the 70/30 NR/LDPE blends produced with 0.3 pphp peroxide was greater than that of the composites prepared without the peroxide and with a high amount of peroxide. Nevertheless, tensile properties, stress and strain of the 70/30 NR/LDPE composite improved with partial replacement of LDPE with recycled LDPE (rLDPE). The composite with 20 pphp rLDPE indicated the best improvement in all physico-mechanical properties.
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    Development of biopolymer filled natural rubber latex-based composite films to enhance biodegradation
    (2021) Jayathilaka LPI; Ariyadasa TU; Egodage SM
    Natural rubber latex (NRL) is the primary resource in developing thin film products including NRL gloves. These comprehensive applications of NRL are lead to the widespread formation of discarded solid material. Majority of these NRL-based product wastes are subjected to an incineration, landfill, or recycling. Recycling of NR waste is not usually effective owing to expensive and inadequate resources. Therefore the generation of heavy buildup of NR waste has become an immense social and environmental issue. Although NRL is biodegradable in nature, it has become more resistant to degradation, with the alteration of its properties to meet the processing requirements. To reduce the rising of NR waste problem, an attempt to enhance biodegradation process by coupling NR with degrading biomaterials has attracted more interest in research. Therefore this study is focused on evaluating applicability of corn-derivatives (cornstarch (CS), corn flour (CF), and corn grain (CG)) to develop a novel NRL-based biocomposite to enhance biodegradation as well as physico-mechanical, aging properties and compare with the conventional fillers. Corn-derivatives were employed to enhance the biodegradability and physico-mechanical properties of NRL-based composite films by changing filler content from 0 to 50 phr. Significant alteration in physico-mechanical properties were noticed with the type of the filler and NR-CG demonstrate improved adherence with NR matrix. Moreover addition of CG in NRL-based composite films increased degradation; with exceeding 70% mineralization detected for 50 phr CG loading after 15 weeks of soil burial. The agreement among physico-mechanical properties and biodegradation restrict the CG loading in the NRL-based composite films to 20 phr by obtaining the specifications of NRL-based products. The results showed that NRL-based composite films with CG loading of 20 phr support to the ASTM D3578, the specification for producing NRL gloves; with 50% mineralization after 15 weeks of soil burial. A glove material was successfully produced with NRL-based compounds including CG 20 phr loading and further improvements of composite films can be done by using it with industrial glove manufacturing process.