engleski

Morphological, rheological and thermal characteristics of biopolymeric microcapsules loaded with plant stimulants

Morphological, rheological, and thermal properties of biopolymeric microcapsules loaded with novel plant growth regulators (2, 3-dehydroaspartic acid dimethyl ester (PGR1), Z-isomer of the potassium salt of 2-amino-3-methoxycarbonylacrylic acid (PGR2) and 1-methyl-3-methylamino-maleimide (PGR3)) were studied. Microcapsule formulations containing PGR2 or PGR3 had a granular surface structure with substructures, whereas those containing PGR1 had smooth surfaces with no grain substructures. All formulations had storage moduli (G ′) greater than loss moduli (G ′ ′), indicating viscoelastic solid behavior. The application of angular frequency over the range tested did not signifcantly change G’ and G’’ values indicating well-ordered structures for all samples. Compared to other formulations, the highest values of storage modulus, yield strength and fow point obtained for formulations with PGR3 indicated an advantage in terms of stability in various physical environments. Thermal analysis showed good thermal stability of all formulations and is consistent with rheological properties confrming well-ordered structures. Encapsulated PGRs afect the intensity of intermolecular forces (electrostatic interaction and hydrogen bonds), thus changing the crosslinking density of the alginate network and the basic physicochemical properties of the formulations.

Microcapsules ; Morphology ; Rheology ; Thermal properties ; Structure/property relationshi

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