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Item Quality improvement of radiation vulcanized natural rubber latex by addition of polyvinyl alcohol and centrifugation(Rubber Research Institute:Agalawatta, 1999) Ratnayake, U.; Makuuchi, K.; Yoshii, F.Effect of polyvinyl alcohol(PVA)on extractable soluble protein content,and on mechanical and physical properties of radiation vulcanized natural rubber latex(RVNRL)was studied with the view of improving properties of RVNR latex.Concentrated natural rubber latex was irradiated at the rate of 10 kgy/h for 2hrs in the presence of 5 phr of n-BA and 0.5 phr of KOH.PVA solution was added to the RVNR latex at three different stages and different time periods were used for leaching to find out the most suitable process to produce soluble protein less RVNR latex.present results indicate that combined treatments of PLVA addition and centrifugation foollowed by leaching were more effective compared to single treatmemt to reduce soluble protein content in RVNR latex films.It could be further observed that,the tear strength was increased whereas tensile strength and tackiness were decreased with PVA concentration.However when the PVA incorporated RVNRL was centrifuged,tensile and tear strenght were not changed up to 2 phr of PVA.Fourier Transrorm infrared slpectrophotometer (FTIR)measurements showed that whem PVA added RVNRL was centrifuged,most of the PVA could be removed with the serum phase,According to the Horixontal Attenuated Total reflectance(HATR)measurements ,PVA concentration on the upper and lower surfaces of the latex films (I.E.the exposed and unexposed surfaces of the films whem drying )was not equal.Item Blends of acrylonitrile butadiene rubber/superior processing/natural rubber and poly(vinyl chloride) Part I. a study of some of the technological properties of NBR/SP rubber/NR/PVC blends(Rubber Research Institute:Agalawatta, 1999) De Silva, K.G.K.; Karunanayake, L.; Muttukkrishnan, K.The advantage s of using superior processing(SP)rubber in place of natural rubber (NR) in blends with NBR and NBR/PVC is discussed here in derail.various technological properties such as tensile,resilience,hardness,compression set,specific gravity,cross-lind density and resistance to oil were measured and compared. It is advantageous to use SP rubber in place of NR in the above blends probably due to higher cross-link density in the SP rubber component when compared to NR. It may be possible to use the ternary blends of SP/PVC? NBR in manufacture of injection moldable and recyclable products due to their thermoplastic natureItem Chemical modification of natural rubber(Rubber Research Institute:Agalawatta, 1991) Pushpa, S.A.; Goonetilake, P.; Silva, S.M.C.E.; Witharana, L.P.; Denawake, I.Item Effect of varied carbon black distribution on the morphology and properties of blends of natural and nitrile rubber(Rubber Research Institute:Agalawatta, 2003) Edirisinghe, D.; Freakley, P.K.Item Future of natural rubber(Rubber Research Institute of Sri Lanka:Agalawatta, 2002) Tillekeratne, L.M.K.Item Strategies to prevent South American leaf blight entering into the territory of the Republic of Sri Lanka(Rubber Research Institute:Agalawatta, 1998) Jayasinghe, C.K.Item An overview of the rubber industry(Rubber Research Institute of Sri Lanka:Agalawatta, 1993) Samarappuli, I.N.Item The automotive industry and the lowest cost producer. an evolving global concept(Rubber Research Institute of Sri Lanka:Agalawatta, 1993) Samarappuli, I.N.Item Impact of production consumption, exports and stocks on the price of natural rubber in Sri Lanka(Rubber Research Institute:Agalawatta, 1997) Wijesuriya, B.W.; Thattil, R.O.The relationship between price of Natural Rubber (NR)with factors such as:production,consumption,exports and stocks are important in identifying the nature of competetion and therefore reveals the market structure for NR.This paper examines these relationships and also the seasonal variation of these factors,using time series statistical tools,viz Cross Correlation Functions (CCF)and seasonal indices. There is a marked seasonality in production with values below average during April to October (2nd and 3rd quarters).Prices tend to fall when the production rises.A similar phenomenon was observed between price and exports.However,the effect of production or exports on price is mild. A similar pattern of seasonal variation was observed for consumption and stocks of NR.More rubber is consumed during the latter part of the year.An accumulation of stocks was observed towards the end of the year.However,price of NR was not significantly related to consumption or stocks.This is mainly due to the fact that only a few buyers influence prices through their purchase and by adjustments of stocks as in an oligopolistic market.