Mesostructure characterization by asymmetrical flow field-flow fractionation of natural rubber samples from different Hevea brasiliensis genotypes

As a biopolymer produced by a tree, natural rubber (NR) entails a major drawback compared to its synthetic counterparts, namely the non-consistency or variability of its properties. One of the most important variability factors is the Hevea brasiliensis genotype producing the latex. The mesostructure (macromolecular structure + aggregates) of NR samples from four Hevea brasiliensis genotypes (RRIM600, GT1, RRIC110 and PB217) was characterized by asymmetrical flow field-flow fractionation coupled to a multi-angle light scattering (AF4-MALS) and refractive index detector (DRI). We first describe the method used to characterize NR samples by AF4-MALS from a qualitative and quantitative point of view. We focused on determining the structural parameters of the microaggregate fraction, leading to the determination of their average molar masses, size and shape. Secondly, we showed that one of the main structural differences in NR samples lies in the density of this microaggregate population. The samples from genotype PB217 contained heavier and more compact microaggregates than the other genotypes studied.