RRI Publications
Permanent URI for this communityhttps://dl-rri.nsf.gov.lk/handle/1/3
Browse
7 results
Search Results
Item Investigation of some factors which effect on rate of evaporation of antioxidants and ultraviolet stabilizers(Rubber Research Institute. Agalawatte, 1996) Goonetilake, S.A.P.P.; Billingham, N.C.Volatility is a physical property which effect the retention of antioxidants during processing and use of polymeric products. The volatility data abtained for such compounds are very useful in choosing an antioxidant for particular application. In this study measurement of volatilities of some phenolic antioxidants and UV stabilizers were done by using an apparartus specially designed for this purpose. It is apparent that the molecular weight and the molecular structure have a significant effect on the evaportion rate of the antioxidants as well as UV stabilizers. The polarity of the compounds also reduces the volatility while the environmental conditions such as vacuum enhances the volatility by a factor of 10.Item An investigation on oil of rubber seed (Hevea brasiliensis)(Rubber Research Institute. Agalawatte, 1996) Njoku, O.U.; Ononogbu, I.C.; Owusu, A.J.Y.Oil from seeds of hevea brasiliensis traditionally used as thickening agent for saurce preparation was isolated, and its physical and chemical characteristics determined. Saponification yielded saturated and unsaturated fatty acids which were seperated by preferential crystallization using organic solvents. Methanol, Ethnol, Hexane and Acetone were found effective solvents inthis regard. Gas liquid chromatography (GLC) revealed large amounts of C18 fatty acids as well as traces of other fatty acids. The iodine values show that the solvents used in this study gave excellent yields of fatty acids with acetone being the most effective as a crystallization solvent to oil ratio 3:1 at 5 oC.Item 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 The effects of the basic medium and the carbohydrate content on shoot cultures of Hevea brasiliensis(Rubber Research Institute. Agalawatte, 1996) Seneviratne, P.; Flegmann, A.W.; Wijesekera, G.A.S.Woody Plants Medium (WPM) was superior to murashige and skoog medium (M S), which showed better axillary bud growth of both juvenile and mature shoot materials. The effect was more pronounced in later passages, in particular, on the survival rate of the cultures. Most of the cultures grown on M S medium did not survive more than 24-28 weeks, while on WPM medium cultures survived for more than one and a half years, until the experiment was terminated. The level of sucrose in the medium also had an effect on the growth of the primary axillary shoots, specially the length and the leaf growth. The length of primary axillary shoots incresed with the increasing levels of sucrose in the medium up to 10 per cent with clonal materials. Explants did not survive beyond 8 weeks when the medium was not supplied with sucrose.Item Kinetic study of the graft polymerization of unsaturated monomers with natural rubber latex and with deproteinized natural rubber latex(Rubber Research Institute. Agalawatta, 1994) De Silva, K.G.K.; Hamielec, A.E.The non-rubber substances present in natural rubber (NR) latex seem to have an influence on the rate of polymerization reaction, degree of grafting grafting efficiency of the graft copolymerization reaction of Methyl Methacrylate on to natural rubber.The released amino acids on enzymatic destruction of phospholipid/protein barrier in natural rubber latex may probably by the cause for the improvement of the reaction kinetics; such that reaction under redox conditions could be conducted without purification of the monomer with inhibitors. Presence of emulsifier, type of enzyme, monomer diffusion time in rubber particle, size of the particle are shown to have an influence on the physical properties of the final product.H NMR has been used to study the composition of the final product.Item Preparation and characterization of rubber seed oil alkyds(Rubber Research Institute of Sri Lanka. Agalawatte, 1995) Aigbodion, A.I.; Okieimen, F.E.Item Epoxidation of rubber seed oil with performic acid(Rubber Research Institute of Sri Lanka. Agalawatta, 2001) Aigbodion, A.I.; Okieimen, F.E.; Bakare, I.O.; Abbey, C.N.