Master of Philosophy (M.Phil.)

Permanent URI for this collectionhttp://192.248.9.226/handle/123/18725

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Now showing 1 - 15 of 15

item: Thesis-Abstract
Characterization and modeling of thermo-mechanical behavior of solid tires with graphite as a heat transfer enhancer
(2023) Somaweera, D; Abeygunawardane AAGA; Weragoda VSC; Ranathunga S
The solid resilient tire construction consists of three layers namely tread, cushion and base. The cushion or the middle layer provides a comfortable ride but also needs to reduce the heat buildup when the tire is subjected to heavy loads. Repeated loading on the cushion compound causes heat generation due to hysteresis and combined with the heat due to friction from tread needs to be relived promptly to reduce the risk of tire damage. The aim of the study is to enhance the thermal properties of the cushion compound of the solid tire using Sri Lankan vein graphite powder as a filler. This study reports mechanical, chemical and thermal properties of vein graphite powder sourced from Bogala mines, Sri Lanka. Five varieties of graphite powder samples were chosen to investigate their potential for application and each were characterized through Thermal Constant Analyzer, Differential Scanning Calorimetry, and Ultrasonic pulse-echo method. The ultrasonic method was adopted to obtain measurements of the Poisson's ratio (ϑ), Young's modulus (E), and Shear modulus (G) of the graphite powder samples. Highest value of thermal conductivity, volumetric heat capacity, and thermal diffusivity was reported from the grade of graphite powder possessing larger particle size. The study also focused on the improvement of the mechanical, curing, and thermal properties of vein graphite filled cushion compounds. The results showed a decrease in tensile strength with the graphite powder content. Maximum torque and the cure time were not significantly changed with the graphite particle content. Furthermore, results revealed a 66% of increase in thermal conductivity at the 10% of graphite particle addition to the compound relative to the unfilled cushion compound. It was observed that tensile strength decreased (with increased hardness) due to low interfacial adhesion and air gaps present between graphite particles and the compound. Furthermore, Dynamic mechanical analysis was performed on the vein graphite filled solid tire compounds to investigate the interaction between graphite and the polymer matrix. Next, an empirical equation, derived from the relationship between theoretical and experimental thermal conductivity values, was established to model the for graphite-iii filled solid tire compound. This equation is a valuable tool for estimating thermal conductivity within the 0-10% graphite filler loading range. Then, a comprehensive tensile test and thermal conductivity test simulations were carried out using Abaqus software and compared the obtained results with experimental data, which was observed to have reasonable correlation.
item: Thesis-Abstract
Development of coir fiber based insulative composite material to reduce thermal heat in buildings
(2022) Chamath LG; Sewvandi GA; Srimal LKT
Energy consumption is a critical factor in building design. Maintaining a comfortable indoor temperature consumes high energy than other necessities such as lighting and cooking. The building envelope is the main component of the building that transfers heat between indoor and outdoor environments. During the daytime, a proper ventilation system or an air conditioning system can control the heat in a building. Insulation layers are also used under the roofing sheets to control the heat transfer through the roof because a building’s roof contributes to a significant heat gain in tropical countries. Sustainable insulation materials have been more attractive in the last two decades due to biodegradability, low embodied energy, availability, and non-toxicity. Sustainable insulation materials are primarily fabricated using lignocellulose fiber (natural plant fibers). Then it is mandatory to add binder material to adhere to fibers and the material formulated as a composite material, and an air void should be introduced to the combination of fiber and binder to increase insulation properties. Now the whole material can be identified as a three-phase composite material. Thus, the volume fraction of each phase (fiber, binder, and air void) is the most critical factor which controls these composites’ insulation properties. The insulation properties of the material can be analysed using experimental, analytical, and numerical methods. Analytical and numerical methods are more attractive than experimental methods. However, there are limited number of studies on the effect of volume fraction with insulation properties in a three-phase composite. In this study, the effective thermal conductivity (K eff ) of the composite was analysed through the analytical and numerical models and validated through the experimental results. The results concluded that the experimental results agreed with the numerical and analytical results. Furthermore, a novel mathematical model has been proposed to find the K eff of the three-phase composite using the analytical and numerical methods. The proposed model shows better agreement with the experimental result. Therefore, it can be used to develop this research area further.
item: Thesis-Abstract
Synthesis of porous graphene from Sri Lankan graphite for supercapacitor applications
(2022) Sandaruwani MKA; Sitinamaluwa HS; Galpaya GDD
A feasible process to synthesize porous graphene with ultra-high surface area is presented in this thesis. Graphene oxide (GO) was synthesized from Sri Lankan graphite via the modified hummers method. Then, GO was subjected to a chemical activation process to produce graphene with a mesoporous structure, where KOH was used as the activation agent. The influence of the critical activation process parameters on the specific surface area of graphene was studied. In this study, activation time at 60 min, activation temperature at 800 ℃ and KOH/GO mass ratio at 4 were identified as the optimum activation parameters for high surface area. As an alternative route to find the specific surface area (SSA), a dye adsorption based SSA calculation method was followed, and the methylene blue adsorption kinetics were studied for that. Second order kinetic model and Langmuir isotherms were the most suitable kinetic models for the methylene blue adsorption onto porous graphene which were produced from Sri Lankan vein graphite. A combined mathematical model of methylene blue number (MBN) and iodine number (IN) was used to calculate the SSA for high accuracy. The obtained optimum activated graphene sample showed a high specific surface area of 768.15 m 2 /g as measured from the dye adsorption method and it was verified by BET analysis. Furthermore, methylene blue and Iodine adsorption methods are studied as a low-cost and feasible method for surface area determination of porous graphene. The high surface area of the obtained graphene would make it a promising material for supercapacitor applications. The present study mainly focuses on the value addition to Sri Lankan vein graphite trough the utilization of vein graphite as an electrode material in electrochemical double layer capacitor (EDLC).
item: Thesis-Full-text
Correlation between the degree of corrosion and the ultrasonic parameters in steel
(2020) Piyathilake SAKVM; Sivahar V
In metallurgical engineering, corrosion is considered as one of the main reasons for the failure of metallic components. The main reason for this is that, the corrosion is a phenomenon which is mainly influenced by the nature itself. It is very important to eliminate or reduce corrosion since it can lead to major disasters which can negatively affect the human lives and properties. Inaccurate estimations, inaccessibility of the areas of corrosion, limitations for the destructive tests can be identified as some of the main reasons for the wrong and misleading preliminary corrosion investigations, which lead to catastrophic failures. Conventionally, the degree of corrosion is determined using destructive testing methods. Also, most of the research work in this area has focused on the uniform corrosion/general attack faced by steels across a range of atmospheres. With those methods, the real degree of corrosion cannot be revealed since it is difficult to address regarding the corrosion penetrations or pits. Therefore, those are inaccurate up to some extent. In contrast to that, Ultrasonic testing methods would be more effective and convenient to overcome above limitations and would be able to open a new area of estimating the degree of corrosion accurately. Also this study sought to contribute to this field by examining whether the penetration of corrosion beyond the general attack has a significant effect on the load-bearing capacity of mild steel. Also,in some cases such as in bridges and pipelines ultrasonic non-destructive method would be really advantageous since it is not only non-destructive but also it will allow reaching inaccessible locations easily. Further,an Ultrasonic wave can easily propagate through steel and its attenuation would provide a measurable reading to express the degree of corrosion including every minor detail. The research work is basically focused on measuring the degree of corrosion accurately using ultrasound attenuation. The selected steel materials were subjected to corrosion in a standard accelerated environment for a defined period of time. Then after a set of experiments, the degree of corrosion has been represented by the weight loss per unit iii area, corrosion rate and the corrosion penetration depth in to the material. Furthermore, the research work was able to cover the area of the mechanical property deterioration. The tensile samples were also corroded in the same standard accelerated environment as mentioned above, and subjected to periodic tensile testing and corrosion weight loss analyses. Further, the corroded samples were examined under optical and scanning electron microscopy to observe the penetration behavior of corrosion in to the material. The results showed that the actual breaking loads deviated negatively from the expected load-bearing capacity, which was determined through conventional methods. This deviation showed a close correlation to the increase of penetration of corrosion with time. Meanwhile, the ultrasound attenuation related to each of those corroded samples was measured simultaneously. Finally, all the data were analyzed through mathematical software such as MATLAB and SPSS to generate final correlations. Thereby, a nondestructive method through ultrasound attenuation was developed to determine the accurate degree of corrosion and to predict the remaining load bearing capacity of corroded structures.
item: Thesis-Full-text
Prediction of corrosion behavior of mild steel in different Sri Lankan atmospheric conditions
Adikari, AAMT; Munasinghe, RGN De S
Corrosion is defined as the deterioration of materials due to the reaction with its environment. According to the physical nature of environment, corrosion can be categorized as 'corrosion in atmosphere', 'corrosion in water', 'corrosion in sea', 'corrosion in soil' etc. Among them, corrosion of steel in atmosphere is identified as one of most important type of corrosion. Because studies show that corrosion cost of a country may vary between 1 to5% of their GDP and about one half of that cost is due to atmospheric corrosion. Corrosion problem cannot be completely eliminated but it is possible to control by methods known as 'corrosion management systems'. Corrosion model is a one of the best tool that can be used for atmospheric corrosion management. Use of a corrosion model as a tool for corrosion prevention is the common practice in many other countries, but using this method is not a popular practice in Sri Lanka due to non availability of such model. Therefore, this project was carried out for the formulation of an atmospheric corrosion model that can be applicable in Sri Lankan atmosphere. For this purpose, by reviewing internationally published literature a model structure was proposed. Then field exposure programs were conducted to obtain data required for model calibration. The model was calibrated with the obtained data and test has been done for goodness of fit and the model shows considerably acceptable goodness of fit with more than 80% of data are within the ±10% deviation from actual value. Finally, a completely different set of samples were placed in different locations and data gathered were used to find out the validity and forecasting capability of the model,. The model shows a good performance in forecasting capability with acceptable deviations.
item: Thesis-Full-text
Theoretical investigation of thermogravimetric analysis on the decomposition of solid-state materials
(2019) Kumara DRD; Amarasinghe DAS; Attygalle D; Weragoda VSC
Thermogravimetric (TG) analysis and differential thermogravimetric (DTG) analysis are the most commonly used analytical techniques to determine the kinetic behaviour of solid-state chemical reactions through Arrhenius parameters and reaction model, which is called the kinetic triplet of solid-state reactions. There are number of methods proposed in the literature for extracting the kinetic parameters of solid-state reactions from TG & DTG thermograms. However, thermal event separation using curve fitting where overlapped thermal events may be present is mandatory before further TG/DTG analysis. In this study, a better curve fitting procedure and a new model fitting method for kinetic parameter extraction is proposed. Enhanced accuracy of the proposed method is proved by MATLAB® based, simulated DTG signals. Furthermore, a mathematical approach using higher differentials of DTG signal was developed to count the number of thermal events in overlapped DTG peaks.
item: Thesis-Full-text
Use of hydrolysis products of polythylene terephthalate scraps to produce alkyd based paint
(2015-10-22) Udayakumara, SV; Gunapala, O
In modern world, plastics play a significant role in our daily life. However Sri Lankans' still have not introduced proper waste management system to daily increasing plastic garbage. Polyethylene terephthalate (PET) is one of the main plastic used in day today life as packaging material, soft drink and mineral water bottles. Sri Lankan peoples alone consumes 6.5 million PET bottles per month but only 1.5 million bottles collected for recycling. This gives clear indication about the role of PET in environmental pollution. This report present development of effective chemical recycling process to depolymerize PET waste into its initial monomers and use of de-polymerized products to synthesized alkyd resin which can be use in coating industry. Depolymerization of PET was done by hydrolysis method to extract terephthalic acid(TPA) . Here Na2CO3 was successfully used as hydrolysis agent instead of highly corrosive NaOH . This overcome the common disadvantages of NaOH . At 170 °C, 35 minutes and 1:4 PET: EG (ethylene glycol) mole ratio 78.89% PET was reacted with Na2CO3 without any catalyst. Recovered terephthalic acid was used to replace Phthalic anhydride in alkyd resin. Due to the inability of conventional alcoholysis method to making alkyd resin from TPA, a new methodology was developed. New Process was successfully incorporated to produce long oil alkyd resin with soya oil, glycerin, maleic anhydride and recovered TPA. Under this new method alkyd processing time was greatly reduced and minimum time achieved was 120 minutes at 280 °C. Practical application of this project to the local PET waste will help to reduce the plastic land fill in Sri Lanka and also provide more beneficial effects to the alkyd paint industry by reducing production time and raw material cost.
item: Thesis-Abstract
Conversion of Sri Lankan iron ore into high quality pellets to be used in iron making
(2015-06-24) Guluwita, SP; Fernando, WLW; Munasinghe, RGNS
Iron ores and lime are two of the available raw materials in Sri Lanka for iron making. However, proven reserves of iron ore deposits in Sri Lanka have not been scientifically estimated as yet. There is no indication of the occurrence of coal deposits in Sri Lanka for the utilization to produce iron using the blast furnace. Therefore, it is important to investigate the possibility of producing high quality iron ore pellets using locally available resources as a substitute for sponge iron which is imported to use in the cupola furnace. In this study it was aimed at obtaining high quality iron ore pellets with required strength, porosity and degree of reduction by varying pellet compositions, firing temperature and soaking time. The pellets prepared with 100 parts of Dela Iron ore, 7 parts of Aruwakkalu lime and 7 parts of coke which was sintered at 1250°C for 10 min gave the optimum crushing strength, apparent porosity and degree of reduction. The subsequent melting of these pellets in the lab scale cupola recovered iron as “metallic pigs‟, which conformed to alpha iron having high purity.
item: Thesis-Abstract
Characterization of weld defects in single V-butt welded mild steel plates using ultrasonic A-scan technique
(3/15/2012) Tennakoon, TMR; Munasinghe, RGNDS
In Ultrasonic A-Scan technique the depth and the size of the defects in a material can be determined by the position and amplitude of the reflected echo on the CRT screen. However the main difficulty in ultrasonic testing is that the precise recognition of the defect type. In conventional ultrasonic A-scan methods recognition of the defect type (porosity, slag, crack etc.) is ascertained by a series of movement of the probe as rotational, orbital, lateral and transverse to observe the echo pattern. Here the human eye perceives many facts simultaneously by moving a transducer in infinite increments in 3D to seek out additional information-the mind sorts and processes the accumulated real-time facts and combines them with empirical data from experience and case history before making final decision on the defect.These uultrasonic echo patterns are quite complex since those may contain many signals other than defect echoes, same defect may display different echo patterns, different defects may display similar echo patterns and the amplitude and shape of the signal may change due to slight movement of the testing probe. Therefore the interpretation of defects using this technique is very complicated and totally depends on the experience of the operator who carries out the testing. Hence only well-experienced NDT personnel can identify defect type using this method. This is one of the main drawbacks related to Ultrasonic A-scan technique. The objective of this research is to study the relationship between type of defect and echo amplitude in single-V butt welded steel plates and to propose a new concept to identify defect type with the help of a self developed software which will be cheep, portable and simple to understand by the operator. To achieve this objective initially a mathematical relationship between echo amplitude and defect type was developed for common weld defects in single-V butt welded steel plates (slag, porosity, crack etc.) using newly derived mathematical equations for above defects. Since the amplitude of the echo signal affects by the defect size this parameter alone can not be used to identify the type of defect. As such the possibilities of using few other features such as width of defect echo, position of defect and change of probe angle also were considered. Experimental results show that any individual defect in single-V butt welded mild steel plates produces echo signals with unique pulse width and range of amplitude levels. In addition the results show that lack of penetration can be identified using a second probe angle in addition to single probe angle as use in conventional methods. Lack of side-wall fusion can be identified by using position of probe with respect to weld center line. These individual characters of defects, which are inherent to those defects, were used to predict the type of unknown defects using a self developed software programme named “ULTRASL1”. The significance of this work is that the introduction of a specialized procedure with a software programme to identify type of defect, so that Non-Destructive Testing personnel with any level of experience can share the expertise of the best operators in the industry. Hence it will support to reduce one of the main problems concerning ultrasonic testing i.e. the difficulties in recognition of defect type. The work was limited for defects like slag(volumetric), isolated pore, porosity, lack of inter-run fusion, lack of side-wall fusion, crack and lack of penetration in single-V butt welded mild steel plates.
item: Thesis-Abstract
Non-destructive evaluation of hardness of stell through ultrasonic attenuation using ultrasonic flaw detector
(7/22/2011) Sivahar, V; Munasinha, RGNDS
This research is focused on establishing a correlation between hardness which is one of the most important material property and ultrasonic attenuation in steels with the intention of developing a method to asses the hardness of steel using attenuation measurements using an ultrasonic flaw detector. The conventional methods that are used to determine the mechanical properties such as hardness not only cause impairment to a certain extent to the materials tested, but also require special sample preparations in most instances. Further, it is obvious that such methods cannot be used on finished products. As ultrasonic testing is non-destructive, using such a technique in the measurement of hardness would be a great advantage for those who need to do so. In this research work five types of steels namely AISI 1045, AISI 4340, AISI 4140, AISI 4142 and AISI 01 were selected. Cylindrical specimens were prepared and subject to various heat treatment processes in order to vary the hardness. Attenuation coefficients were determined using an ultrasonic flaw detector and hardness values were obtained with a Vickers hardness tester. The work carried out showed a linear variation in the attenuation coefficient with the hardness values of for all the types of steels used. The relationship between attenuation coefficient (a) and hardness (H) of quenched and tempered steels can be generalized as a = f SH, where 'f' is the frequency of the ultrasound used and 'S' is a factor that depends on the composition of steel. The relationships obtained for AISI 4140, AISI 4142 and AISI 01 steels were α=4xO.0245xH, a=4xO.024~xHand a = 4 x 0.0 152 x H respectively, when the frequency of ultrasound used was 4MHz.
item: Thesis-Abstract
Development of a glazed clay body suitable for cookware
(7/22/2011) Jayawardane, JTST; Adikary, SU
This research work describes development of a glazed red clay cookware body with adequate thermal shock resistance. Two red clay deposits were investigated (Malwana and Hambanthota region) which are currently used for pottery industry. X-ray diffraction analysis (XRD), chemical analysis, differential thermal analysis (DTA) and scanning electron microscopic investigation (SEM) were used to determine the clay properties. Thermal compatibility of red clay and different fritted glazes were investigated using thermal expansion and thermal shock resistance of individual body/glaze components. This investigation revealed that the coefficient of thermal expansion of red clay was lower than all tested glazes. Therefore it was difficult to formulate a suitable glaze to match the red clay body. Quartz was incorporated into red clay to increase the thermal expansion of the body. According to the results, thermal shock resistance decreased with increasing quartz content of the body. The thermal shock resistance and coefficient of thermal expansion of red clay body were investigated with different proportions of quartz asl0%, 20%, 30%, 35% and 40% at a firing temperature of 10500C and isothermal holding time 30 minutes. The behaviours of the thermal conductivity, thermal shock resistance and important mechanical properties such as modulus of rupture and modulus of elasticity of each formulated body were studied. The results revealed that thermal conductivity increased with increasing quartz content of the body. Modulus of rupture and modulus of elasticity were decreased with increasing quartz content of the body. Initially to preserve the red colour appearance of the product, it was decided to use a transparent glaze and three transparent glazes were investigated. Coefficients of thermal expansion of these transparent glazes were theoretically compatible with body composition having a quartz content of 30%. Actual size cookware samples were fabricated and required properties were tested under actual domestic conditions. But they were not successful on direct heating test. Body compositions with 35% and 40% quartz were investigated and they also gave the same results. Hence it was necessary to develop a body with better thermal shock resistance having low quartz content. For this purpose glaze with low coefficient of thermal expansion was required and a semi matt glaze was selected by partially sacrificing the red colour appearance of the body. Malwana red clay body with 25% quartz hewing a coefficient of thermal expansion 60.31xl0·7 x' and thermal shock resistance 0.97 kJ m-1s-1 and the glazes having coefficient of thermal expansion in the range of (49-51) xl0-7 K-1 and thermal shock resistance in the range of (1.10-1.20) kJ m-1s-1 could be effectively used to manufacture a glazed red clay cookware product. It can be concluded that a suitable body composition for glazed cookware production could be formulated by incorporating quartz in correct proportion to kaolinitic type red clay.
item: Thesis-Abstract
Enhancement of surface quality brass castings cost effectively using naturally available sand and clay available in Sri Lanka
(7/2/2011) De Silva, GIP; Munasinghe, N
Through a survey done for the Sri Lankan foundry industry using a structured questionnaire it was revealed that one of the most significant quality parameter of the brass casting is the high surface roughness. Properties of the sand clay- mixture, the gating system of the mould, composition of the material to be melted and pouring temperature are the factors, which affect the surface roughness. Out of these factors the attention was focused in this work to the properties of the sand-clay mixture like fineness no., clay content, moisture content and permeability etc. to reduce the surface roughness. A synthetically unmodified sand-clay mixtures consisting of natural sand and clay from different locations in Sri Lanka were analyzed with respect to the reference sand sample (naturally bonded sand-clay mixture) imported from Japan, which gives a considerably low surface roughness. In this research work the attention was also directed to develop a non-contact method to measure the surface roughness of castings using ultrasonic echo amplitude technique. With this method it is possible to measure the surface roughness of castings with improved accuracy and minimized cost. The results of the experimental work done in this work show that it is possible to produce several number of mixtures made by mixing different sand and clay available in Sri Lanka and those mixtures give a relatively good surface roughness for the brass castings with compared to the casting made with Japanese reference sample.
item: Thesis-Abstract
Modelling of the vulcanization process of thick-walled natural rubber articles
(7/2/2011) Weragoda, VSC; Gunapala, PY; Munasinghe, RGNDS
A computer-based technique was developed to render the state of cure in thick-walled natural rubber compounds as measured by the oscillating disk rheometer torque. The method was based on a mathematical function derived to replicate the rate of change in the rheometer torque with respect to the curing time and the curing temperature. The mathematical function was able to trace the temperature related changes in the rheometer curves of different rubber compounds exceptionally well, at a 99.9% level of certainty. This was used to model the vulcanisation process for thick-walled articles through a deterministic simulation approach, which was made it possible to predict the scorch time, curing time, and the time for onset of reversion to a precision within ±5%, as verified against programmed a temperature profile curing in a rheometer. This study also investigated the variation of the thermal conductivity and the thermal diffusivity of rubber compounds during the curing process, to determine the effectiveness of such variations in estimating the curing time of thick-walled rubber articles. The experiments were carried out using a modified hot wire technique. The coefficient of variation in the thermal diffusivity was estimated at 20%, and the same for the thermal conductivity was found to be 15%, for the compounds tested. The simulation model showed that this variation was not significant in affecting the curing time.
item: Thesis-Abstract
Enhancement of mechanical properties in the heat affected zone of AA 5083 weld joints
(6/24/2011) Mirihanage, WUS; Munasinghe, N
Decline of Mechanical properties were observed at the Heat Affected Zone (HAZ) of the Gas Metallic Arc Weld (GMAW) joints of the Aluminium Alloy (AA) 5083. It was concerned as a direct effect of the weld thermal cycle on the work hardened material. Experimental efforts were aimed to set up a post welding procedure to recover this decline of properties. Presence of the Silicon in AA 5083 was significant in the experimental considerations due to its tendency of forming Mg2Si precipitates at intensified temperatures. A series of mechanical and microstructure observations were done to evaluate the effectiveness of the post weld heat treatment, with the AA 5083. According to the experimental results heat treatment at 473K for 10 minutes produced the most effective improvement of mechanical properties at the HAZ of weld joint.
item: Thesis-Abstract
Preparation and characterization of low density polyethylene/modified chitosan/papain composite
(5/26/2011) Samarasekara, AMPB; Adikary, SU
The objective of this research was to impart biodegradability to a polyethylene blend using Chitosan as the main additive which was extracted from fishery waste. Papain, a natural enzyme derived from papaya plant, was also used to enhance the biodegradability. The biodegradability of this Polyethylene blend was studied using low molecular weight chitosan both in the presence and absence of papain. The influence of concentration and type of alkali on the chitin yield and chitosan obtained from deacetylation process were investigated. Low molecular weight chitosan was prepared by different depolymerization methods. This study investigated the time dependent weight loss using soil burial test, stress – strain properties and water absorption properties of the developed polymer, to evaluate the degree of biodegradability. The Fourier transform infrared spectroscopy (FTIR), Differential thermal analysis (DTA), Thermogravimetric analysis (TGA) and optical and Scanning electron microscopic investigation (SEM) were used to determine the properties of LDPE – Chitosan – Papain composite. The optimum composition for the industrial trial production was selected by considering the tensile strength, elongation, optimum degradability as well as good processability. Industrial trial production was done using composition containing of LDPE with 5% chitosan and 3% papain by weight. Soil burial test results showed that specimens degraded by 60% in a six month period, while complete degradation occurred after one year. Since experimental analysis did not indicate formation of new bonds, it could be concluded that Chitosan, LDPE and Papain are present in the final product as a physical mixture without any detectable chemical reactions among different constitutes. Products manufactured in industrial scale also showed appreciable biodegradable properties. The biodegradation mechanism proposed for LDPE – Chitosan – Papain composite is based on the hydrolysis followed by actions of microorganisms.

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