Электронный каталог

Статья

Svishcheva, N.B.
Rheopectic Вehavior of Pseudoplastic Systems Based on Boron-Containing Oligomers of Lactic Acid / N.B.Svishcheva, A.V.Vlasov, [a.o.]. – Text : electronic // Materials Today Chemistry. – 2026. – Vol. 54. – P. 103627. – URL: https://doi.org/10.1016/j.mtchem.2026.103627. – Bibliogr.: 21.

Using rheological analysis and solid-state &sup(11)B NMR spectroscopy, composites of polylactic acid (PLA) with boric acid (BA) and boron anhydride (BAA) (0.1 – 1 wt%) were investigated. The introduction of boron switches the PLA melt from a degradation to a structure-forming regime: the storage modulus G′ at the yield point increases from 79 to 153,300 Pa (145 &sup(o)C), and the viscosity under constant shear increases by 27–102% (whereas for neat PLA it decreases by 27–35%). A discrepancy is observed between the increase in elastic characteristics and the molecular weight (M&sub(w) increases by no more than 14%), indicating the contribution of additional structural factors beyond chemical crosslinking. NMR data confirm the formation of covalent B–O–C bridges (a decrease in the quadrupole coupling constant by 12–34%, the appearance of an isotropic component). Analysis of the molecular weight distribution showed that after isothermal treatment, the loss of Mw is 45% for neat PLA and no more than 12% for composites with BAA. Thus, boron-containing modifiers can enable control over the rheology and melt stability of PLA, and a dual mechanism (chemical bonding and the formation of shear-induced supramolecular structures, analogous to layered silicates) is suggested as a possible model to explain the rheological behavior.



Спец.(статьи,препринты) = С 350 - Приложения методов ядерной физики в смежных областях
Спец.(статьи,препринты) = С 44 г - Физико-химические методы анализа элементов. Анализ с помощью ядерных методов
ОИЯИ = ОИЯИ (JINR)2026