Research Symposium-2015

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Browsing Research Symposium-2015 by Author "Alakolanga, A.G.A.W."

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    Development of Green Tea incorporated Ayurvedic toothpaste
    (Uva Wellassa University of Sri Lanka, 2015) Ranasinghe, D. N. C.; Alakolanga, A.G.A.W.; Arachchi, M.P.M.
    The tea plant Camellia sinensis is native to South East Asia and consumed worldwide, although in greatly different amounts. It is generally accepted that, next to water, tea is the most consumed . Green tea contains polyphenolic compounds, which include flavanols, flavandiols, flavonoids, and phenolic acids and account for 30% of the dry weight of green tea leaves. Green tea contains compounds that appear to control inflammation and fight bacterial infection. This drink is also rich in antioxidants, which have many oral health properties as Cavity prevention, Gum health, Less tooth loss, Cancer control, Better breath (Lisa, 2011). But the oral health benefit of the green tea is less aware by the people (Narotzki et al, 2012). This study is aimed to develop green tea incorporated ayurvedic toothpaste by addition of five different herbs to enhance the natural flavor of the tooth paste while increasing the oral health benefits. The main objective is to develop ayurvedic toothpaste incorporating green tea and evaluate it for selected quality parameters. Other objectives are to determine the appropriate green tea and herbal oil incorporation quantity, to evaluate taste of the toothpaste (strength, bitterness), liquor color, smell, freshness after washing and the overall acceptability as quality indicators. Materials and Methods The green tea ayurvedic toothpaste consists with chemical mixture, green tea extract and herbal oil. To prepare the toothpaste chemical mixture 325g of powdered Calcium Carbonate (CaCO3), 5g of Carboxy Methyl Cellulose (CMC), 10g of Sodium Lauryl Sulfate (SLS) and 2g of Methyl Paraben were mixed well during 15 minutes. And 110 mL of distilled water, 70 mL of glycerol and 70 mL of sorbitol were mixed in a separate dish and poured in to the solid chemical mixture and mixed together until 30 minutes. It was stored in a sealed container. To extract the herbal oil 110g of each powdered Clove, Welmee, Munamal and Aralu were ground by adding 100 mL of distilled water until herbal pulp was formed. And the pulp was boiled during 10 minutes at constant temperature while mixing with 500 mL Sesame oil until evaporated the total water amount. Green tea – water extraction was done using reflux extractor (ISO 1574:1980). To prepare the green tea ayurvedic toothpaste all the three ingredients (chemical mixture, green tea and herbal oil) were mixed together at 1% , 2% of green tea extract and herbal oil levels. Sensory evaluation with 30 untrained panelists was carried out to select the best green tea, and herbal oil incorporation quantity for the formulated toothpaste. Five point hedonic scale was used to evaluate samples for taste (strength, bitterness), color of the paste, smell, freshness after wa shing and the overall acceptability. Data were statistically analyzed using Freidman test at 5% level of significance using MINITAB statistical software. The pH value of the developed toothpaste was measured with electronic pH meter. Determination of Moisture and Volatile Matter, Foaming Volume and Stability of the toothpaste were done based on SLS 275:2006 specifications. Determination of polyphenol content of the toothpaste was done according to the ISO 14502-1 specifications. Prepared green tea ayurvedic toothpaste and control were tested for well diffusion assay using experimental microorganism included Strephylococcs aureus and the mean zone inhibition was measured (Awadalla et al, 2011). A total plate count test was done to determine the microbial evaluation of the toothpaste. The prepared mouthwash was subjected to a storage study by observing color and the smell at two weeks intervals and the pH of the product also measured. Results and Discussion Analyzed statistical data of the sensory evaluation of first experiment revealed that, there was a significant difference (p<0.05) among five treatments in respect to the all the sensory attributes tested. According to the Figure 1, Second treatment combination (475) which consisted of 1% of green tea extract and 2% of herbal oil amounts were selected as the best treatment to develop the new product since each of the significantly different attribute bears the highest rank mean and median values except colour of the product
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    Effect of graphite derivatives on mechanical and functional properties of nitrile rubber nano composite
    (Uva Wellassa University of Sri Lanka, 2015) Rajapaksha, P. C.; Alakolanga, A.G.A.W.; Weerawansha, A.N.; Rathnayake, U.N.
    The conducting polymers and polymeric composites have attracted considerable attention in recent years because of their breadth applications in advanced technologies, for example, in antistatic coatings, electromagnetic shielding. For all applications, elastomers are reinforced with fillers to promote their performance by incorporating materials such as silica, clay, carbon blacks, etc. Graphite is a layered material with high aspect ratio in its exfoliated state; it is also considered as one of the strongest materials per unit weight and has unique functional properties such as good electrical and thermal conductivities, and good lubricating properties. In other side graphene have recently received significant attention due to its outstanding electronic, mechanical and thermal properties. NBR-based Nano composite was prepared and mechanical and functional properties were studied. The dispersion of the filler in the polymer matrix was studied using the Transmitted light metrological microscope. Methodology Two different experimental trials (Preparation of NBR/Graphite composite and NBR/Graphene Nano composite) with different treatments (Phr levels) were conducted during this study. Nitrile rubber composites were prepared accordance with Brabender Plasticorder (Model: PL-2000; 26 manufacturers: ArtisanTM Technology Group).
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    Optimization the physical properties of carbon black filled tread compound by replacement with silica
    (Uva Wellassa University of Sri Lanka, 2015) Perera, W.P.M.D.A.; Alakolanga, A.G.A.W.; Weerawansha, A.N.; Kularathna, S.
    In tire industry, carbon black (CB) is a widely used filler all over the world (Studebaker, 1965). Being a product made out of petroleum, there would be scarcity issue with the time, if continue to use in which it is being used today. It is a high time to look at feasibility of replacing CB with an alternative such as silica partially/fully as a solution for foreseen scarcity. Compared to CB, there won’t be scarcity as due to the fact it is made out of quartz (SiO2) which is readily available in earth crust. In this research, an attempt has been made to study the feasibility to go for possible replacement with silica while meeting the physical property requirement of a tread compound. Methodology The current study was carried out at Loadstar (Pvt) Ltd, Ekala. This study was conducted as two separate experiments. In experiment I, optimum CB/Silica combination which gives overall physical properties was evaluated. Five tread compounds were prepared. Each compound has the same ingredient except filler amount. Total filler amount was kept constant at 50 phr level. Carbon black and powder silica was varied in the ranged from 0 to 50 phr level to prepare the tread compounds with different CB/Silica ratios. Weight of all ingredients in the recipes was in units of per hundred rubbers. Batch weight was 1100 kg. Compound without silica was treated as the reference compound. The compounds were named as Si0, Si15, Si25, Si35 and Si50 to indicate the amount of silica incorporated in the compounds. Silane was added when incorporation of silica as 1 phr of Silane for 8 phr of silica as the coupling agent. Experiment II was carried out to find out the effective silica type in order to optimize the physical properties. Better treatment combination from the experiment I was selected and it has been treated with three silica types (Powder silica, Hi-sil 243 and New-sil 155). Physical properties such as: tensile strength, tearing, abrasion resistance, 300 % modulus, elongation at break, hardness and rebound resilience and cure characteristics were measured in both experiments. Four replicates were used for each test. Data was analyzed with one way ANOVA using Minitab 16 statistical software and mean comparison was done using Tukey test. Results and Discussion According to the previous studies it shows that the increasing silica loading tends to increase in the cure time (t90) and scorch time (ts2) of the rubber vulcanizates (Okel and Waddell, 1994). These properties have increased with increasing silica. At 15 phr level of silica, it tends to reduce the scorch protection. This can be due to the insufficient coupling of silane with silica during compounding. Higher processing safety obtained as silica loading high due to formation of
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    Visco-elastic properties of OMMT filled fractioned bleached crepe rubber
    (Uva Wellassa University of Sri Lanka, 2015) Wijesinghe, H.G.I.M.; Alakolanga, A.G.A.W.; Withanage, N.S.; Ratnayake, U.N.
    Natural Rubber (NR) latex tapped from Hevea brasiliensis converts into an important engineering material for different applications. NR latex pale crepe, the purest form of NR produced by Sri Lanka, is mainly used in pharmaceutical and surgical applications, infant toys, food contact rubber articles and adhesives, (Senevirthne and Kumara, 2003). Natural Rubber has a higher greenstrength as but it is soft and has lower dimension stability (Cohan and Spielman, 1948) which is one of the major draw backs in NR for engineering application. Recently, Nanoclays such as montmorillonite clay are attracted as an alternative filler to achieve the reinforcement of rubber compounds by replacing conventional fillers (Ratnayake and Peiris, 2010). Study the effect of Organo-montmorillonite (OMMT) on the visco elastic properties of fractioned bleached crepe rubber will helpful for the advancement of the raw rubber industry as value addition. In this study, OMMT dispersion in the rubber matrix has studied not only by Mooney viscosity and stress relaxation properties but also by the physical properties of vulcanizates. Therefore this study may help to have an advantage for the development of crepe rubber industry and product manufacturing industry in Sri Lanka. Material and Methods NR field latex was obtained from NR processing factory at Rubber Research Institute, Dartonfield, Agalawaththe. Montmorillonite clay modified with quaternary alkyl ammonium salt (OMMT)was used as the nanofiller. Other general chemicals and laboratory equipment were obtained from Rubber Research Institute, Rathmalana. Initially, 5%(w/w) aqueous dispersion of OMMT was prepared using a surface active agent as a dispersing agent. Latex mixing/intercalation method(Gatos and Kocsis, 2010) was carried out to prepare OMMT filled fractioned bleached crepe rubber (OFBCR). Dry rubber content (DRC) of fractionated bleached latex was diluted up to 10% and subsequently OMMT dispersion was incorporated to latex samples at OMMTloading from 0 to 8 phr with an interval of 2 phr, with simultaneous stirring.Standard latex crepe manufacturing procedure was adopted to prepare OFBCR (Senevirthne and Kumara, 2003). Laces were dried in the drying tower at 34°C for three days. Complete randomized design was applied to assign treatments, T 0(0 phr), T2 (2 phr), T4 (4 phr), T6 (6 phr) and T8 (8 phr). The NR was characterized based on DRC and the OMMT was characterized by the ash content. Money viscosity and stress relaxation of OFBCRs were measured according to the [ISO/R 289- 1963] by the Ektron Mooney viscometer. Then the OFBCR samples were compounded according to the pre-determined formulation. Curing characteristics of the OFBCR samples were measured by using MDR 2000 (moving die rheometer, M/S Alpha Technologies, USA) at 150°C according to the ISO 3417:2008 procedure. OFBCR samples were moulded by hydraulic hot press at 150°C temperature and 20MPa pressure for optimum cure time derived from the cure characteristics data.The tensile properties of OFBCR samples were determined by “Instron 3300 Series” material testing machine at a crosshead speed of 500 mm/min as per ISO 37:2011. The hardness of the samples were determined using Elastocon bares digi hardness tester according to the ISO 48:2010. Compression set at constant strain was measured according to ISO 815-1:2008 test method andtear strength of OFBCR samples were determined by “Instron 3300 Series” material testing machine at a crosshead speed of 500 mm/min according to ISO 34- 1:2011. All tests were carried out at 27±2°C and each test was replicated at least 3 times. Data were analyzed by using the Minitab 16 statistical software with the use of General Liner Model (GLM) with Tukey’s all pair wise comparison tests at 95% confidence interval. Results and Discussion Field latex used for the preparation of nano crepe rubber showed the dry rubber content of 30%. OMMT clay has modified with quaternary alkyl ammonium salts. The ignition weight loss of OMMT is 43%–48%. Ash content of clay is 52%-58%. This ash content represents the amount of silicates and other inorganic metal amount in the clay. Ignition weight loss is correlated to the amount of quaternary ammonium alkyl modifier and adsorbed moisture amount in the clay. Mooney viscometer is an instrument to measure the 'stiffness' of uncured compounds, the result of that viscosity is called as Mooney viscosity at ML 1+4 (100°C). Mooney stress relaxation coefficient is the slope of the power law model when it is in logarithmic scale (log M = a(log t) + log k) where M- torque units from the Mooney stress relaxation test, k- a constant equal to torque 1 s after the rotor has stopped, ‘a’- an exponent that measures the rate of stress relaxation and t- testing time. Also elasticity of rubber material is inversely proportionate to the ‘a’andlower elasticity improves the mixing of rubber and processing, especially extrusion and calendaring. Malac J., (2009). Clay loading level (phr) has significantly affected to the Mooney viscosity expressed as ML (1+4) 100°C of OFBCR samples (p-0.000). Only T6 and T8 has not indicated a significant difference (p-0.0569) between them with respect the Mooney viscosity but all other treatment levels are significantly different among (p-0.000). Mooney viscosities for T0, T2, T4, T6 and T8 are presented in Figure 1. The reason for the reduction of Mooney viscosity is, when increasing the OMMT loading, the plasticization of rubber material by OMMT and may possibly be the chain slippage over the clay platelets (Kader et al., 2010). As reported in Figure 2, the stress relaxation coefficient has increased up to 4 phr and there after it reduces. The maximum stress relaxation coefficient has indicated at the 4 phr clay loading level, therefore, it can be concluded that OFBCR with 4 phr OMMT clay loading has a better processability than other samples. Long relaxation times and high amplitudes of stress relaxation suggest the mechanism of structural relaxation involving large-scale displacements of isolated clusters of nanoparticles within the rubber matrix and vice versa (Dick, 2010).