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Retardation effect of nanohydroxyapatite on the hydrolytic degradation of poly (lactic acid)
Author(s) -
Watai Juliana Satie,
Calvão Patrícia Schmid,
Rigolin Talita Rocha,
Bettini Silvia Helena do Prado,
Souza Adriana Martinelli Catelli
Publication year - 2020
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.25459
Subject(s) - crystallinity , hydrolysis , hydrolytic degradation , differential scanning calorimetry , degradation (telecommunications) , materials science , arrhenius equation , lactic acid , activation energy , size exclusion chromatography , polymer chemistry , nuclear chemistry , chemistry , composite material , organic chemistry , biology , enzyme , bacteria , telecommunications , physics , genetics , computer science , thermodynamics
Poly (lactic acid) (PLA) and PLA/nanohydroxyapatite (nHA) composites, containing 2 wt% and 5 wt% of nHA were subjected to in vitro hydrolytic degradation tests in saline phosphate solution at different temperatures (37°C, 48°C, 60°C, and 72°C) to accelerate degradation. Samples were characterized by water uptake, weight loss tests, size exclusion chromatography (SEC), differential scanning calorimetry (DSC), and visual analyses. Arrhenius equation was used to describe the behavior of weight loss as a function of time. The PLA activation energy of weight loss showed to be lower than that of the PLA/nHA composites, indicating that the incorporation of nHA retarded the hydrolytic degradation. The rate and percentage of weight loss increased with increasing temperature. All samples presented a decrease in T g and an increase in degree of crystallinity as a function of time. Incorporation of nHA retarded this behavior that showed to be more expressive in PLA containing 5 wt% nHA.