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Poly( para ‐dioxanone) and poly(L‐lactic acid) blends: thermal, mechanical, and morphological properties
Author(s) -
Pezzin A. P. T.,
Van Ekenstein G. O. R. Alberda,
Zavaglia C. A. C.,
Ten Brinke G.,
Duek E. A. R.
Publication year - 2003
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.11984
Subject(s) - materials science , differential scanning calorimetry , crystallinity , glass transition , scanning electron microscope , crystallization , polymer blend , polymer , morphology (biology) , plasticizer , casting , optical microscope , ultimate tensile strength , miscibility , composite material , polymer chemistry , chemical engineering , copolymer , physics , genetics , biology , engineering , thermodynamics
Abstract Blends of two semicrystalline polymers, poly( L ‐lactic acid) (PLLA) and poly‐ p ‐dioxanone (PPD) have been prepared by solvent casting in different compositions. Thermal, morphological, and mechanical properties of the blends were studied using modulated differential scanning calorimetry, wide‐angle X‐ray diffractometry, scanning electron microscopy (SEM), polarizing light microscopy (PLM), and tensile tests. Thermal analysis showed two glass transition temperatures nearly constant and equal to the values of the homopolymers and constant values of melting temperature ( T m ) for all blend compositions, suggesting that both polymers are immiscible. The PLM and SEM observations validated these results, and showed the different morphology obtained by changing the composition of the blend. The blends 40/60, 50/50, and 60/40 presented a clearly macroseparated system, while the 20/80 and 80/20 blends presented better homogeneity, probably due to the low amount of one component in the other. It was found by PLM that PPD is able to crystallize according to a spherulitic morphology when its content is above 40%. Under this content, the crystallization of PPD is hardly observed. The blend 20/80 is more flexible, and tough material and neck formation during elongation is also observed, due to PPD, which may act as a plasticizer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 12: 2744–2755, 2003