Palm and Latex Technology and Value Addition Degree Programme ( PLT)

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    Effect of Biochar on Soil pH and pH Buffering Capacity of Rubber Growing Soils
    (Uva Wellassa University of Sri Lanka, 2013) Rathnayaka, R.A.G.S.
    PurposeThe effect of biochar on pH and pH buffering capacity of rubber growing soils, and the effect of nitrogen fertilizers on pH in biochar amended rubber growing soils wereinvestigated in this study. Materials and methods Three soils with contrasting properties i.e. RYP from Paiyagala estate, RBL from Parambe estate, and RBE from Thanamalwila, were collected from traditional and non-traditional rubber growing areas and amended with three different biochar types (G1, PH and RW) and three different rates (0, 2 and 5%). After incubation of soils at 70% WHC, the change in pH was measured with time. The pH buffering capacity was determined using Ca(OH)2 titration method. The values of pH buffering capacity were obtained from the slope of titration curves of alkali additions plotted against pH in the pH range 4- 8.5. Two N fertilizers (urea and sulfate of ammonia) were applied into soils from Thanamalwila and Paiyagala that were amended with 0 and 2% rubberwood biochar by weight. The change in pH was measured with time after mixing soils with BC and N fertilizers. Results and Discussion Application of biochar increased soil pH. Once after the addition of biochar, higher soil pH was in Thanamalwila soil compared to the Paiyagala and Parambe. But pH change was higher in Paiyagala soil (— one point pH increase) than Parambe (less than one point) and Thanamalwila soils (less than 0.5).With the time pH changes were different in different soils with different biochar types and biochar rates. As incubation time increased from 1 to 12 weeks, the pH did not increase significantly (P<0.05) in Thanamalwila and Paiyagala soils, and the gap decreased in significantly (P<0.05) Parambe soils. pH buffering capacity had a range of 4.7-11.8 mmol kg-1 pH-1 for three soils from rubber growing areas. The pH buffering capacity was highly correlated (R2= 0.8696) with soil cation exchange capacity. Addition of rubber wood biochar, which itself had a higher CEC and alkalinity increased soil CEC, and thus increased pH buffering capacity more compared with that of Gliricidia and paddy husk biochar. For Thanamalwila soil, biochar rate*N rate interaction and biochar rate*N source interaction were not significant different (P<0.05). Thanamalwila soil pH (6.1) was the highest out of three soil types. pH was negatively related with urease activity. Conclusion The application of biochar increased soil pH in all three soils. Thanamalwila had the highest soil pH buffer capacity and paiyagala had the lowest pH buffering capacity as well as CEC. pH buffering capacity of rubber growing soils 5ould be increased by amending them with biochar. Addition of biochar generated from rubber wood, gliricidia and paddy husk not only ameliorate soil acidity, but also increased soil pH buffering capacity. The pH increase in biochar amended paiyagala soil could be arrested by addition of sulphate of ammonia and urea, but not in Thanamalwila Foil. Key words Biochar, Nitrogen fertilizer, pH buffering capacity, CEC, pH, WHC
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    Effect of Enzymatic Discoloration Inhibitor on Plasticity Retention of Sole Crepe Rubber
    (Uva Wellassa University of Sri Lanka, 2013) Somarathna, W.D.S.P.
    Durability of rubber product 4s very important to customer. As well as manufacture of rubber products try to protect good properties throughout the consuming time period of the product Durability of raw rubber product is affected aging properties. According to time, most of raw rubber is degradation which is leaded to reduce the properties of raw rubber and less performance of the product. Thermal oxidation is one of badly effect the aging property of raw rubber product. The rubber molecular weight of product will be reduced from thermal oxidation. Resistance to thermal oxidation is measured by plasticity retention index. Sole crepe rubber manufacturing industry always tries to produce higher grade sole crepe. Colour, clearness and purity are affected to grading parameters for sole crepe rubber industry. The colour of sole crepe rubber is manly affected enzymatic discoloration of the natural rubber latex which is complex process. In sole crepe manufacturing industry under fractionation step, Sodium matabisulfite (enzymatic inhibitor) is used to prevent enzymatic discoloration. Through the process, resistance of oxidative components is removed with yellow fraction. As a result plasticity retention index also significantly reduced. Increasing the dosage of Sodium matabisulfite the value of plasticity retention index is reduced. If is not used fractionation process to sole crepe manufacturing process the plasticity retention index is not reduced. Clone is also effected to plasticity retention index to sole crap rubber. Clones of less yellow fraction (RRIC 121 and PB 86) can be treated less dosage of Sodium matabisulfite. Then less effect to plasticity retention index from of Sodium matabisulfite. Kay word: Plasticity retention index, Sodium matabisulfite, Sole crepe, Colour, Effect
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    Evaluate the Different Gum Extracting Tapping System of Cashew Tree (Anacardium Occidentale L)
    (Uva Wellassa University of Sri Lanka, 2013) Wickckrama Arachchi, W.A.W.D.
    Cashew (Anacardium occidentale L.) is a perennial crop which gives its harvest once in the year and in rest period there is no much attention to crop. Economic life span of the cashew tree is about 30 years. Thus utilization of unproductive and old plants is important to obtain continuous economic benefits to cashew farmers. Cashew gum is by product and synthesized in the epithelial cells lining pockets or canals and then secreted into internal cavities. There are many application potentials of cashew gum in food, pharmaceutical and stationary industry. Therefore the objective of this study was to evaluate different tapping system for extracting cashew gum. The study was conducted in Puttlam district. The experiment plot was laid down in two factor factorial design with main two factors as treatments with four replicates. Two factors were shape of cut and tapping depth. Cashew trees were tapped by using rubber tapping knife. Growth parameters and yield parameters of selected trees were recorded. Data were analyzed using Minitab analytical software package and SAS analytical software package. Result revealed that there was no significant relationship between growth parameters and cashew gum yield. Further it showed that, there was a good potential to extract gum by using a tapping method. Among these sixteen tapping systems, horizontal shape cut 100% depth was the suitable tapping system to extracting cashew gum. Key words: Cashew, Cashew gum, growth parameters, Bark depth, Cashew tree tapping, Gum exudation
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    Isolation of Antagonistic Organisms Against Rigidoporus Microporus from Soils of Main Rubber Growing Areas in Sri Lanka
    (Uva Wellassa University of Sri Lanka, 2013) Jayamuthu, J.P.D.L.
    Soil microbial community plays a critical role in rubber plantations. Especially, microorganisms that involve in biological control of root rot disease are considerable. White root disease is the most destructive root disease in Sri Lankan rubber plantations. It is caused by the fungal pathogen Rigidoporus microporus which spreads through infected roots and mycelial aggregates (rhizomorphs) through the soil. The purpose of the study was to isolate the potential antagonistic micro¬organisms from different rubber growing against white root disease in Sri Lanka. The micro-organisms were isolated from twelve sites in four main rubber growing districts viz. Kaluthara, Rathnapura, Kegalle and Monaragala. Nested design was conducted for the experiment as statistical design. The antagonistic ability of the isolated organisms was tested against the fungal pathogen R. microporus. Growth inhibition of the pathogen's colony was measured using dual culture plate technique investigate the most promising antagonistic microorganisms that would be useful in controlling the growth of R. microporus. The variation of soil properties, microbial populations among sites and districts were and the growth inhibition of pathogen was analyzed using analysis of variance (ANOVA) procedure of SAS software programme. Significance of the data was determined at 95% confidence interval (a=0.05). The abundance of the microbial population varied with their environment. A total number of thirty one colonies were found effective. Antagonism of selected antagonistic microorganisms was varied significantly. Both fungal and bacterial isolates selected were effective in antagonistic effect and therefore are suitable to be developed as biological control agents against white root disease of rubber tree. Key words: microbial community, antagonism, Rigidoporus microporus, biological control, white root disease
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    Initiation of Callogenesis from Unfertilized Ovary Explants of Oil Palm (Elaes Guineensis Jacq)
    (Uva Wellassa University of Sri Lanka, 2013) Herath, H.M.D.M.P.
    Oil palm is an efficient oil producing crop which has high economic value. Due to lack of vegetative propagation method, tissue culture remains the only approach to produce clonal plantlets for oil palm. Unfertilized ovaries obtained from immature female inflorescences of oil palm (Elaeis guineensis Jacq.) were tested as a source of explants for callogenesis. The callus induction possibility was examined through maturity stages of inflorescence, different culture media and 2,4-D concentrations. Callus multiplication possibility using the same callusing media was tested. Inflorescence maturity stages of -2, -3 and -4 were cultured on Y3, CRI 72 and OPC3 media supplemented with 2,4-D levels of 160 pM, 180 IAM and 200 p,M. Development of callus was visible during the seven weeks after culture. Callus proliferation occurred when subcultured in to the same medium. It was found that there was no significant difference and interactive effect among treatments tested. The results achieved suggest that unfertilized ovaries of immature female flowers of oil palm (Elaeis guineensis Jacq.) can be used as alternative sources of explants for the induction of callogenesis. Callus tissues of oil palm ovaries can be established and grown in culture. Callus can be subcultured in the same callusing medium and it is possible to multiply the callus. Key Words: Oil palm, Callogenesis, Ovary explants, in vitro culture, Culture medium
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    Reducing the Time of Coir Retting by Changing the Conditions of Microbial Environment
    (Uva Wellassa University of Sri Lanka, 2013) Wimalasena, P.T.N.
    Sri Lanka is the largest coir exporter in the world and Sri Lankan coir has a great market demand in the coir market. But today Sri Lanka has faced to difficulties because of the low productivity compared with other competitor countries. The coconut husk which is a fibrous material that covers the fruit of Cocos nucifera is the raw material for extracting coir fiber. The retting process is responsible for the separation of bristle fiber from the husk and it undergoes two distinguished physical and biological changes. This study was done to reduce the retting time of coir by changing the microbial environment of retting tank and to increase the productivity of Sri Lankan bristle fiber. The experiment procedure was done in three stages as preparation of nutrient media, changing the pH value of retting water and supplying of aeration to the retting tank. There were six treatment combinations and the control. Six increasing retting days were applied as 7, 14, 21, 28, 35 and 42 days. At each week microbial studies and coir quality analyzing were done. Best quality coir sample was analyzed statistically by grouping comparison in Tukey method. Treatment combination T5 (50% of nutrient media, 3L/min air volume with pH9) and T6 (75% of nutrient media, 3L/min air volume with pH9) were reduced retting time by giving relatively higher best results for average breaking load and elongation at break within 14 days of coir retting. And also above two treatments were given relatively higher best results for physical requirements of bristle fiber. Weighted average tensile strength, fineness, size distribution of coir, average length distribution, and average diameter distribution of coir were analyzed as the physical requirements of coir. pH variation of retting water of each sample in weekly intervals and isolation of bacteria were also done. Treatment combination, T3 (50% of nutrient media, 3L/min air volume with pH7), T4 (75% of nutrient media, 3L/min air volume with pH7), T5 (50% of nutrient media, 3L/min air volume with pH9) and T6 (75% of nutrient media, 3L/min air volume with pH9) were given relatively higher results for average total colony count and colony forming units within 14 days of coir retting. Key words: Coir retting, Microbial environment, Physical requirements, Retting time, CFU
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    Validation of Uv-Visible Spectrophotometric Method for Estimation of Phosphorous Content in Palmyrah Jaggery
    (Uva Wellassa University of Sri Lanka, 2013) KIRTHIKA, J.
    UV-Visible spectrophotometry is a widely using optical quantification method of concentration of solutes in a wide range of solutions. However, method validation is important in order to achieve accurate, precise and reproducible results. Therefore, the UV-Visible spectrophotometric method was validated according to international committee of harmonization (ICH) standard during the study and Phosphorous content in Palmyrah jaggery in the form of Phosphate was estimated. Absorption maximum ( .max) of the Phosphate in the Palmyrah jaggery was found to be 400 nm by scanning sample solution into the range of 300-500 nm. The standard curve was constructed for the Potassium dihydrogen phosphate in the range of 1-10.igm1-1 at 400 nm wavelength. The method was validated in terms of linearity, accuracy, range, precision, and ruggedness, limit of detection and limit of quantification. The method was shown linear in 1-7 )..tgml-1 concentration range having line equation 84.824x - 0.0016 with 0.9998 correlation coefficient (r2). The recovery values were in the range of 100.22% to 100.88% and confirmed the accuracy. The percentage relative standard deviation (RSD %) of precision was in the range of 0.55-1.55% and confirmed the reliability and repeatability. The RSD% of ruggedness was in the range of 0.8964 — 0.9920%. The limit of detection and limit of quantification were 0.05115 p.gm1-1 and 0.1534 pigm1-1 respectively and the low-value levels showed a better the sensitivity. Hence, the proposed method was precise, accurate and reproducible. This method could be applicable for quantitative determination of the Phosphorous in the form of Phosphate in Palmyrah jaggery. Keywords: Palmyrah jaggery, Method validation, Spectrophotometer
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    Production of Edible Copra and the Evaluation of Shelf Life
    (Uva Wellassa University of Sri Lanka, 2013) Chandranayake, M.R.S.
    Short the shelf life, high level of residual sulfur dioxide and high production cost are the major problem in Sri Lankan value added (VA) copra. High valve Sri Lankan residual sulfur limit is 50 ppm but in most situations it goes up to 100 ppm. So it is necessary to produce high quality copra that having low residual sulfur levels. Another problem in VA is the short shelf life and the changes color within six month period. Hence it is necessary to understand the factors limiting the shelf life. Therefore experiments were conducted to estimate total plate count (TPC), yeast and mould (Y and M) and residual sulfur dioxide levels during storage period, untreated copra, ozone treated copra, glacial acetic acid (GAA) and in the copra produced by using indirectly heated copra dryer. Newly produced 2013 VA copra shows 101.38 ppm residual sulfur dioxide level and 2011 VA 88.4 ppm. Controller and GAA copra gives below 10 ppm residual sulfur dioxide. There was a significant increase in TPC during five month storage period. The Y and M counts not increase significantly in copra and the residual sulfur dioxide levels found to be reduced. Hence TPC can be a factor to limit shelf life of VA copra. GAA copra gives unsuitable brown color. Indirectly heated copra dryer gives economical MS2 copra, 3.1 MT copra in every 3 days and weekly 6.2 MT of copra, copra under any climatic conditions and an additional income from coconut shells but the colour obtained is not suitable for VA copra. Key Words: value added copra, shelf life, residual sulfur dioxide, total plate count, yeast and mould
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    Effect of Storage Conditions on Viscoelastic Properties of Crepe Rubber
    (Uva Wellassa University of Sri Lanka, 2013) Jayasinghe, A.C.C.
    Latex crepe rubber is one of main raw natural rubber types produced in Sri Lanka. Rubber as a viscoelastic material, it consists with both viscous and elastic properties. Viscoelastic properties of raw rubber influence the processability of a rubber compound. Even though Sri Lanka is the leading manufacturer of latex crepe rubber, converting crepe rubber into products is carried out in other countries and as a result, manufactured crepe rubber should be kept under storage conditions prior to processing. The objectives of this study were to study the effect of storage conditions on the viscoelastic properties of raw crepe rubber, viscoelastic properties of compounded crepe rubber and the effect of the non-rubber content on viscoeastic properties of crepe rubber. Two factor factorial design was employed as the statistical design of the study. Fractionated Bleached (FB), Un-Fractionated Un-Bleached (UFUB), Yellow Fraction (YF) were considered as three different grades of crepe rubbers. These crepe rubber were stored at different temperatures such as 2 °C, 22 °C, 30 °C and 40 °C. Samples were drawn in every two weeks interval up to six weeks and analysed for viscoelastic behaviour by analysing Mooney viscosity and stress relaxation. Plasticity Retention Index (PRI) and un-aged plasticity (Po) of crepe rubber were also measured to study the thermo-oxidative respect to different storage temperature and time. Data was analyzed by using Duncan's Multiple Range Test. Mooney viscosity and un-aged plasticity were gradually increased with the increasing storage time and increment storage temperature. YF was exhibited the highest Mooney viscosity and un-aged plasticity because of the availability of high content of non-rubber. PRI values were gradually decreased with the increasing storage time and increasing storage temperature. High stress relaxation rates were exhibited by both FB and UFUB crepes. Low stress relaxation rate was exhibited by YF crepe because of the availability of low rubber content. Compounded crepe rubbers were exhibited comparatively low Mooney viscosity values and rapid relaxation rate than raw rubbers. Low Temperature storage conditions are most preferable to maintain satisfactory viscoelasticity and resistance to oxidation of crepe rubber which could finally affect to the better processability of rubber compound. Key words: crepe rubber, viscoelasticity, Mooney viscosity, stress relaxation, non¬, rubber substances
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    Assessing the Impact of Addition of Mica Filler to the Neoprene Glove Manufacturing Process
    (Uva Wellassa University of Sri Lanka, 2013) Weerasekara, R.A.K.S.
    The synthetic rubber based supported glove industry plays the major role in rubber industry. In terms of economic advantage, the chemical handling gloves are more dominant compared to others. The chemical resistant Neoprene gloves are high cost products. In the current study, I examined the Mica is a cost reduction filler as well as reinforcement of the product. The incorporation of 5phr of filler was significantly improved the properties of glove. The glove weight is a critical parameter in terms of quality of the glove. There are number of factors are affecting to the variation of glove weight. The viscosity of the compounded latex is most crucial in determining the glove weight. The P value = 0.00 at 95% and 99% confidence interval. The weight is increased at the high viscosity levels and vise versa. Key words: Neoprene latex, Mica filler, Viscosity, Cost reduction, Glove Weight
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    Coir Fibre Waste as Effective Raw Material for Fibre Boards Reinforced with Natural Rubber Latex Compounds and Phenol-Formaldehyde Resin
    (Uva Wellassa University of Sri Lanka, 2013) Liyanage, W.L.A.M.
    Coir pith is a by-product resulted in extraction of coir from coconut husks. Small fibre particles namely "Kcitu" (-5 mm) are accumulated during coir pith extraction process as a waste material, which has been an issue in the production process. There is a potential to utilize "Kiitu" as an economically viable raw material to manufacture coir boards (CBs). CBs can be used as alternative source for Hard & Particle Boards and other synthetic boards. An effort was made to develop a CB as an alternative to the above boards evaluating the basic parameters. Processing was undertaken using a coir cutter machine and then it was developed in to CB. Each CB (15 x 15 x 0.5 cm) was prepared using 35g of "Kc7tu" changing the mass of Natural Rubber Latex Compounds (NRLC) and Phenol-Formaldehyde Resin (PFR). Mass of NRLC in CBs varied as 30, 40 and 50 g and the PFR as 5, 10, 15 and 20 g. Having moulded, vulcanization was carried out at 120 'C for 20 min. For the CBs, moisture content (%), density (kg m-3), water absorption (%), swelling and physico-mechanical properties such as maximum force at break (N) and maximum elongation (%) were evaluated according to the ASTM and IS standards. Tests were carried out at 27 °C temperature. CBs were prepared successfully by optimizing the composition. The density of CBs was within the acceptabl&'range: 465.8 - 653.61 kg M-3, which is close to the density of 'Hard Boards' and 'Particle Boards'. Moisture content, water absorption and swelling properties were up to the standards. The force at break and maximum elongation showed an increase when the amount of NRLC and PFR was increased. In conclusion, "Katu" can be used as an effective raw material for manufacture of CBs reinfording with NRCL and PFR for the use of other boards given above. Keywords: Coir fibre board, natural rubber, phenol-formaldehyde
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    Evaluation of Suitability of Disulfide Based Natural Product as a Reclaiming Agent for Ground Rubber Tyre
    (Uva Wellassa University of Sri Lanka, 2013) Rathnawardhana, N.N.
    Reclaimed rubber is a solution for the shortage of raw rubber and the rise in the cost of virgin rubbers. Also, it reduces the rubber waste and hence the pollution caused by that waste. So there is a continual development of reclaiming technologies over the last few years. In this study disulfide based natural product was used as the reclaiming agent for ground rubber tyre (GRT) with the aim of replacing the hazardous reclaiming agent Tetramethyl thiuram disulfide (TMTD). A series of rubber compounds was produced by blending the reclaimed rubber prepared with different amounts of the natural product with virgin natural rubber (NR). Physico-mechanical properties and cure characteristics of these compounds were evaluated and compared with those of the control; blend compound containing virgin NR and reclaimed rubber prepared with TMTD. Scorch time, cure time, cure rate index, tensile strength and ageing properties are superior to those of the control. Hardness, tear strength, elongation at break and resilience are also at an acceptable level for tyre treads. Abrasion resistance of natural product added revulcanizates is similar to that of the TMTD added vulcanizates. Therefore readily available, environmentally friendly disulfide based natural product selected for this study could be an alternative to hazardous TMTD in reclaiming of ground rubber tyre. Therefore natural product is suitable for the reclaiming of GRT. Key words: Ground rubber tyre, reclaiming, cure characteristics, mechanical properties, tyre treads
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    Determination of Shell Charcoal Yield of Different Coconut Varieties in Sri Lanka Under Optimum Temperature Condition
    (Uva Wellassa University of Sri Lanka, 2013) Perera, W.N.U.
    Due to the improper management, inefficient use of resources, use of low quality inputs and production procedures, charcoal production in Sri Lanka has become a less profitable industry which pollutes the environment while cause health problems to the workers and also to the society. Laboratory experiments were carried out at Coconut Research institute, Lunuwila to examine Optimum condition for charcoal production and Best charcoal yielding variety out of four coconut varieties named CRIC 60, CRIC 65, CRISL 98, Kapruwana. The carbonization was effected using particle sizes (5mm) at carbonization temperatures between 200 and 500°C in a laboratory muffle furnace. The study involved determination of yield, rate of weight loss, optimum temperature, determination of ash, volatile matter fixed carbon and moisture contents of the carbonized carbon, suitable resident time for carbonization and maximum charcoal yielding variety with its quality parameters. The results showed Kapruwana variety gives maximum yield of 46.59% of carbonized product. It had 0.67, 14.83, 2.12 and 84.5% ash ,volatile matter, moisture content and fixed carbon respectively. The carbonization temperatures of 350°C at resident time of 15 minutes with one hour cooling time were the optimum production conditions for coconut shell charcoal. Key Words: Charcoal, Carbonization, Optimum conditions, Quality parameters, Coconut shell
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    Performance of Different Rainguard Types Types for Rubber (Hevea Brasiliensis Muell.Arg)
    (Uva Wellassa University of Sri Lanka, 2013) Navarathne, H.M.N.D.
    Well distributed moderate rainfall is essential for good growth and production of natural rubber by rubber trees (Hevea brasiliensis). However, rainfall may also be a limiting factor for tapping activity. In addition to that, due to loss of crop, rainguard is used as modernizing latex technology to conserve the yield loss from spells and diurnal rainfall pattern. Also bark become drier faster with rainguard after the rainfall was ceased. This research study was conducted at RRI at Agalawatta to evaluate the performance of different rainguards types on rubber yield. Observations were made by using three types of rainguards. These rainguards types were Apron, Kissan and Belgium type. These three types of rainguards were evaluated to compare the effectiveness of rainguard preventing rain disturb and rubber yield, tapper's efficiency on each rainguard types and tapper attitude on rainguarding. In addition to that financial analysis at the present condition of the rubber industry was conducted. Consequently Apron type and Kissan type significantly effect on yield of rubber, while less significant effect reveals in Belgium type. Where as time taken to tapping process, Apron and Kissan type shown significant effect, and yet Belgium type shown no significant effect with the control, Apron type resulted highest overall preference from tappers. This study revealed that at the present condition of the rubber industry, Kissan type and Apron type are financially worthwhile. However, it is recommended to conduct the trial for one year period with annual rainfall pattern and cause to determine the profitability of rainguards allocate with the repairs in shelf life of the rainguard types. Key words: Tapping process, Rainguard, Financial analysis
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    Effect of Maturity Level on Quality and Yield of Virgin Coconut Oil (Vco) and White Coconut Oil (Wco)
    (Uva Wellassa University of Sri Lanka, 2013) Dasanayaka, D.P.N.L.
    The raw material for the production of coconut oil is the kernel obtained from the fruit of Cocos nucifera L. Level of fruit maturity impacts on extraction yield and physicochemical characteristics of the derived oils. The correct maturity level to be used for VCO and WCO extraction is not adequately studied. Therefore, study was conducted to evaluate the effect of 3 maturity levels (fresh 11 months old, fresh 12 months old, fully matured & 3 weeks seasoned coconuts) on extraction yield and physicochemical properties of VCO and WCO. Copra and desiccated coconut obtained from three maturity levels were tested for moisture content, fat content and free fatty acid content. The VCO and WCO obtained were analyzed for moisture content, free fatty acid content, color, relative density, fatty acid profile, total phenolic content, oil yield and oil recovery percentage. Experimental design used was complete randomized design (CRD). The lowest oil extraction yield was observed in fresh eleven month old coconuts. Fresh twelve month old coconuts and fully matured seasoned coconuts produced similar oil yield percentage. There was no significance difference of moisture, color, free fatty acid, relative density, total phenolic content of coconut oil samples from three maturity levels. Maturity levels showed no effect on physicochemical properties of VCO and WCO. Extracted VCO from the three maturity levels showed significance difference among lauric acid percentage. Fully matured seasoned coconuts had the ( highest lauric acid content (52.32 %). In white coconut oil showed no significant difference in fatty acids composition among three maturity levels. Fresh twelve months old coconut and fully matured seasoned coconut can Abe used for VCO and WCO production. Keywords: Maturity Level, Physicochemical Properties, Virgin Coconut Oil, White Coconut Oil, Yield
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    Development of Natural Rubber (NR) and Ethylene-Propylene-Diene-Monomer (EPDM) Rubber Blend for Tie Down Strap Compound
    (Uva Wellassa University of Sri Lanka, 2013) Karunarathna, A.K.S.
    The tie down strap is mainly used to hold tarpaulins securely in heavy duty vehicles by providing high tensile strength and constant tension during transportation. Tie down strap is made out of pure natural rubber (NR) or pure ethylene-propylene-diene monomer (EPDM) rubber depending on the climate they are being used. NR tie down straps have high tensile strength but easily crack and split due to deterioration of NR in warmer climates. EPDM rubber tie down straps are designed for wanner climates but, it has low tensile strength. Therefore, development of a tie down strap by blending NR and EPDM together to obtain both desired properties of NR and EPDM rubber is worthwhile. This research study was conducted to develop a suitable tie down strap compound having the best NR/EPDM blend ratio. Then the effect of a compatibilizer on NR/EPDM blends was also tested. Nine different blend ratios (N90:E10, N80:E20...N10:E90) were prepared by mechanical blending and they were tested for cure characteristics and physical properties (tensile strength, elongation at break, tear strength, tension set and hardness) with respect to the product specifications (Samson rubber products, 2012) of tie down strap. The same series of blends were further evaluated by adding a compatibilizer (methacrylate-butadiene-styrene or MBS) and similar properties were measured. The results revealed that, NR: EPDM blend ratios of 90:10, 50:50, 30:70 and 10:90 have achieved acceptable cure characteristics according to the given product specifications. When physical properties were concerned, only N90:E10 blend has achieved almost all the physical properties of the product specification except tension. Cure characteristics and physical properties have not significantly changed after adding the compatibilizer. Therefore, it can be concluded that NR/EPDM blend ratio of 90:10 is more suitable for tie down strap compounding and the added compatibilizer has not significantly affected on cure characteristics and physical property improvement of NR/EPDM blends. Key words: Tie down Strap, NR/EPDM Blend, Compatibilizer, Cure characteristics, Physical properties
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    Effect of Palm Oil as an Alternative Plasticizer Tyre Tread Compound
    (Uva Wellassa University of Sri Lanka, 2013) Siriwardana, U.P.
    Sri Lanka is the leading exporter of solid tyres for off road vehicles, accounting for nearly 20% of the global market. Petroleum based mineral oils play a major role as plasticizers in tyre compound formulation. Mineral oil plasticizers are nonrenewable resources and some of them have been identified as carcinogenic. Besides, annex 17 of the EU REACH Regulation restricts eight PAHs and extender oils contain more than 1 mg/kg of BaP, or more than 10mg/kg of the sum of all restricted PAHs. Therefore applicability of palm oil as a cost effective, renewable and eco-friendly alternative was investigated throughout the experiment. Experiment was carried out to investigate curing characteristics, physical- mechanical properties and thermal oxidative properties of a NR/ SBR based black tyre tread compound. Aromatic, naphthenic and paraffinic mineral oils and palm oil were separately assigned for a previously determined compound formulation as treatments. CRD method was used and each property was tested and measured independently with appropriate number of replicates according to the ISO procedures. Palm oil based tyre tread compound signified better performance in abrasion resistance, rebound resilience, elongation properties and lowest compression set. Tensile properties of the compound were also in admissible level with respect to other plasticizer based compounds. Rheometrical data implied the lowest delta cure value for palm oil based compound and hence reduction of the crosslinking density. Therefore palm oil can be used as an alternative plasticizer for mineral oil plasticizers with even better performances and co-activator effect of palm oil in curing system is suggested for further investigations. Key words: Palm oil, Plasticization, Mineral oil plasticizers, Cure characteristics, Mechanical properties
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    Improving of Adhesion in Laminated Rubber Glove Process and Incorporation of Recycled Coagulated Centrifuged Latex
    (Uva Wellassa University of Sri Lanka, 2013) Lakmali, R.G.N.
    As latex based product laminated glove is coming under household category use for the heavy duty purposes and for construction industry. Laminated Rubber sheet is used as a composite to palm area with textile fabrics (Kevlar, Cotton) .The low adhesion causes to separate of laminated rubber sheet from the fabric and low quality. The emphasis was placed on enhance the adhesion ability while introducing of new method to incorporate recycled coagulated centrifuged latex with the laminated rubber sheet manufacturing. The research was conducted at the Workwear Lanka (Pvt) Ltd at Biyagama. Preliminary trails were based on common formulas of adhesive and the existing process line. To fix the accurate secondary solvent (SBP) amount and the accurate viscosity and the TSC of the adhesive, the amounts (SBP) were adjusted into Oml, 50m1, 100m1, 200m1, 300m1 and 400m1. Then modifications of the current process line by changing smoothing turns (one, two), maturing period (0,24,48 hours), curing temperature (120°C,155°C,160°C), time(30,60,90 minutes) and the adhesive formula under different curing temperatures and times were done using modified adhesive blend to enhance the adhesion. Adhesion test was done for all experiments. Then the coagulated centrifuged latex (5kg) with high moisture content was recycled and incorporated it as the filler to the laminated sheet compound. Mechanical testing, moisture content and rheograph characteristics were measured, for the incorporated sheet and data were analyzed by using Tukey method and Dunnett test of MINITAB 16 statistical software. The adhesive blend with 200m1 (SBP) has significant difference (p<0.05) among other treatments and the T16 process line has the significant different (p<0.05) among other process lines. The high wood resin amount with the lowest temperature and longest time period has the significant different (p<0.05) between each other treatment levels. There are no significant differences (P>0.05) the results of mechanical tests, rheograph characteristic§ and the moisture content between the existing and the incorporated laminated sheet. The, highest adhesion ability was resulted under the optimum SBP amount (200m1) with 78.7 viscosity and 93.7 TSC value, double time smoothing, (24 hours) maturing period, low curing temperature (120 °C) , high curing time (90 minutes) and with high amount of wood resin and there is a potential to incorporate of recycled rubber as the cost reductfon filler ingredient.Key words: Adhesion, Cotton, Kevlar, Coagulated centrifuged latex, (Secondary Solvent) SBP
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    Development of a Lightweight Composite Board by Using Coir Fiber and Calcium Carbonate
    (Uva Wellassa University of Sri Lanka, 2013) Jathunarachchi, P.N.
    Composite boards like ceiling sheets, partition boards are vital raw materials in the construction industry. These are commonly made up using asbestos fibers and cement which lead to a high cost of production and health hazards. But, there is a possibility of using coir fiber to make the composite boards as value added products in the coir industry. Therefore, this research was conducted to develop a lightweight composite board. Calcium carbonate was used as a filler to utilize the waste of acetylene plant, to reduce the cement usage further. There are nine treatment levels (C 10B, C1 OM C25Y) with three different coir fiber types (Bristle fiber, Mattress fiber and Baby fiber) and three different calcium carbonate weight ratios (10%, 20% and 25%). The experimental design was two-factor factorial with three replicates. Mechanical properties such as dry weight, thickness, density, water absorption and flexural strength were tested according to the SLS 9: Part 1: 2001. Properties of the developed boards were compared with the accepted properties of asbestos cement ceiling sheets to select the best composite board. Results revealed that, there is a significant influence from fiber type on thickness, density, water absorption and bending strength of the boards. Calcium carbonate weight ratios significantly influence on dry weight, thickness, and density and bending strength of the boards. Interaction of fiber type and calcium carbonate significantly influence only on bending strength of the boards. Except the bending strength, all tested properties of the board having Cl OB treatment have achieved the standard values of currently using composite boards made with asbestos fibers and cement. Therefore, the ClOB (board with bristle fiber and 10% of the calcium carbonate weight ratio) can be used to produce suspended ceiling boards or interior partition boards. Key words: Composite board, Cement, Coir fiber, Calcium carbonate, Mechanical properties
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    Development of Ready-To-Drink Beverage from Coconut Water of DC Mills
    (Uva Wellassa University of Sri Lanka, 2013) Kumara, W.G.M.
    Coconut liquid endosperm is the inner most part of the coconut (Cocos nucifera) fruit and it is rich in nutrients. Mature coconut water is considered as a waste and removed from desiccated coconut industries. This active pollutant pollutes the surrounding environment. Development of a beverage from this waste water may be a good solution but coconut water beverage has shorter shelf life. Processing, preservation and proper packaging may be extending the shelf life. pH, titratable acidity, total soluble solids (TSS), total sugar and minerals ( Mg, Ca, K, Na and Fe) of DC nut water were analyzed. The pH and Brix value adjusted coconut water was pasteurized by heating at 80 °C for 5 minutes, heating at 80 °C forl 0 minutes, heating at 90 °C for 5 minutes and heating at 90 °C for 10 minutes. The treated nut water was filled into sterilized glass bottles and aluminum pouches. Bottles and aluminum pouches were stored separately at both ambient (30±2 °C) and refrigerated (4±2 °C) temperatures. The processed nut water was analyzed for TSS, acidity, pH, mineral content, total sugar, microbial infestation and sensory properties. According to the sensory data coconut water pasteurized by heating 80 °C for 10 min was better in colour attribute and pasteurized by heating 80 °C for 5 min had better odour, taste and overall acceptability. There were no any significant difference (P > 0.05) in pH, Brix and titratable acidity on storage time, packaging materials, storage condition and Pasteurizing temperatures and time. Though Total Plate Count and yeast and mould count were significantly different on storage time (P < 0.05), there was no significant difference on storage conditions, packaging materials, pasteurization temperature and time. Also there was no interaction effect between storage time, storage condition, packaging material, pasteurization temperature and time. The optimum pasteurization condition was 80 °C for 10 minutes, based on microbiological results and sensory parameters. This pasteurization temperature and time combination was better in prolonging the shelf life of DC nut water for eight weeks period and the products were microbiologically safe for consumption. Key Words: Pasteurization, Shelf life, Liquid endosperm