The angiogenic properties of natural rubber were evaluated in this work. We have used the chick chorioallantoic membrane assay (CAM) as a model to investigate the influence of the heating on biological activity in rubber membranes and in non rubber fraction as well. Results showed that natural rubber membranes can induce vascularization. It was observed that angiogenesis activity was maximum when membranes were heated in temperatures between 65ºC and 85ºC, considering a range from 55ºC to 105ºC. The same behavior was observed for non rubber fraction and it indicates that this serum fraction may be responsible for angiogenesis. When infrared spectroscopy was performed in the cast films of non rubber fraction samples, as a function of heating, no structural changes was observed. The results obtained shown that natural rubber latex films produced by casting induce the vessel growth in the CAM and it can be considered as a potential biomaterial.

A indústria da borracha está cada vez mais exigente em relação à qualidade e a uniformidade da borracha natural produzida no Brasil. Neste trabalho as propriedades tecnológicas do látex e da borracha natural dos clones de seringueira GT 1, PB 235, IAN 873 e RRIM 600 [Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell.-.Arg] foram avaliadas pelos ensaios padrões do conteúdo de borracha seca (DRC%), porcentagem de nitrogênio (N%) e porcentagem de cinzas (CNZ%) por dois anos consecutivos; os dados obtidos foram correlacionados com dados de temperatura e precipitação. As propriedades do látex e da borracha natural variaram (P < 0.01) em função do tipo de clone e entre coletas. O DRC% diminuiu no início da estação seca (maio a junho), enquanto N% e CNZ% aumentaram. O período de abril a junho revelou ser crítico, pois os valores da N% oscilaram acima 0,60%, fora dos padrões estabelecidos pela norma técnica brasileira ABNT/NBR. O clone RRIM 600 foi menos suscetível às variações climáticas.

Rubber industry has increased the requirements for quality and uniformity of natural rubber produced in Brazil. Technological properties of latex and natural rubber of clones GT 1, PB 235, IAN 873 and RRIM 600 [Hevea brasiliensis (Willd. Former Adr. de Juss.) Muell.- Arg] were evaluated by standard methods of the dry rubber content (DRC%), percentage of nitrogen (N%) and percentage of ashes (ASH%) in two consecutive years; data were correlated with temperature and precipitation. Properties of latex and natural rubber varied (P < 0.01) as a function of clone type and among tappings. DRC decreased in the beginning of the dry season (May to June) and N% and ASH% increased in the same period. April to June was a critical period, when N% was above 0.60%, out of standards established by the technical standard ABNT/NBR in Brazil. Clone RRIM 600 was less susceptible to climatic variations.

Este trabalho teve como objetivo avaliar parâmetros do látex e da borracha natural de quatro clones de seringueira [Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell.-Arg.] cultivados em larga escala na Fazenda Cambuhy no Município de Matão, Estado de São Paulo. Foram utilizados látex de 20 árvores do estande de cada um dos clones, GT 1, PB 235, IAN 873 e RRIM 600, com 12 anos de idade, no quarto ano de sangria sob o sistema 1/2S d/3 6d/7. 11m/y. ET 5,0%. Pa 12/y. Foram analisados o conteúdo de borracha seca, porcentagem de cinzas, porcentagem de nitrogênio, plasticidade Wallace (P O), índice de retenção de plasticidade e viscosidade Mooney (V R). O conteúdo de borracha seca apresentou tendência de queda com o decréscimo da temperatura ao longo do ano (r = 0,75). Contrário ao conteúdo de borracha seca, as propriedades porcentagem de nitrogênio e porcentagem de cinzas apresentaram tendência de aumento com a redução da temperatura ao longo do período das coletas. A correlação entre P O e V R foi linear e elevada (r = 0,93). Os altos valores de P O e V R indicam que as borrachas dos clones estudados são consideradas como borrachas duras. Os valores do índice de retenção de plasticidade foram baixos, indicando baixa resistência à degradação térmica. Os resultados mostram influência marcante dos fatores climáticos em algumas propriedades dos látices e da borracha natural dos clones estudados, sugerindo condição importante para se entender o comportamento dos mesmos.

The objective of the present paper was to evaluate the parameters of latex and natural rubber from four clones of rubber tree [Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell.Arg.] planted in large scale in Cambuhy plantations in São Paulo State, Brazil. Latex from 20 trees of each 12-year-old clones viz. GT 1, PB 235, IAN 873 and RRIM 600 following the 1/2S d/3 6d/7. 11m/y. ET 5.0%. Pa 12/y tapping system in the fourth year of yielding. The studied parameters were percentages of dry rubber content (DRC), ashes and nitrogen, Wallace plasticity (P O), plasticity retention index (PRI) and Mooney viscosity (V R). Results indicated a trend of reduction in DRC with decreasing temperatures (r = 0.75). Results of ashes percentages and N percentages indicated a behavior opposite to DRC, increasing with the decreasing temperature along the year. A high correlation value (r = 0.93) was obtained between P O and V R. The high values obtained for P O and V R indicate that the rubber studied should be considered as hard rubbers. The PRI values for these clones were considered low and are associated with a low resistance to thermal degradation. The results obtained indicate a strong influence of climatic conditions on some properties of the lattices and natural rubber for the studied clones. Such parameters suggest an important condition to understand the behavior of these clones.