Structural Characterization of Natural Rubber Recent Research Advancements

The micro-structure of the surface of Hevea brasiliensis latex particles has been found by the means of atomic force microscopy (AFM), confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), cryogenic transmission electron microscopy (cryo-TEM), and electrokinetics over a broad range of KNO3 electrolyte concentrations (4-300 mM) and pH values (1-8). Based on the atomic force microscopy analysis of the fresh natural rubber latex, it could be estimated that the protein-lipid layer is covered with the rubber particles. The molecules in the particle were labeled with fluorescent Rhodamine (RB), and were monitored by CLSM. SEM and TEM were used to observe the surface of fresh natural rubber particles and were dyed by osmium tetroxide. Fourier Transform Infrared Spectroscopy (FTIR) has been used to characterize the nitrogenous groups in natural rubber and deproteinized natural rubber (DPNR). The FTIR and H-1-NMR analysis of phosphatase-treated DPNR confirmed that the presence of mono-and diphosphate terminations without phospholipids was also unlikely owing to the presence of a methylene proton signal of an isoprene unit linked to mono- and diphosphate groups. The (Mn) over bar, [eta] and Higgins' k' of DPNR decreased after being treated with lipase.