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Stress–strain behavior of blends of bacterial polyhydroxybutyrate
Author(s) -
ElTaweel S. H.,
Stoll B.,
Höhne G. W. H.,
Mansour A. A.,
Seliger H.
Publication year - 2004
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.21215
Subject(s) - crystallinity , glass transition , amorphous solid , polyhydroxybutyrate , materials science , plasticizer , ultimate tensile strength , strain (injury) , composite material , phase (matter) , stress (linguistics) , polymer , chemical engineering , chemistry , organic chemistry , bacteria , medicine , linguistics , philosophy , biology , engineering , genetics
A series of blends of bacterial poly( R ‐hydroxybutyrate) (PHB), with different miscible amorphous components, were prepared. The molecular mass of the amorphous components was varied from M n ≈ 600 to 200,000 g/mol. Several factors were found to influence the stress–strain behavior of PHB blends: the glass‐transition temperature, the average molecular mass of amorphous phase, the content of PHB in the blend, the crystallinity, and the drawing temperature. It was found that a high extension ratio at rupture λ R > 3 is obtained only if the PHB content is less than 60% (crystallinity X c < 0.4), although this holds only for blends of bacterial PHB with a high molecular mass ( M n > 30,000) amorphous component. The lowering of glass‐transition temperature by the addition of low molecular mass additives (plasticizers) deteriorates the tensile properties. Measurements at elevated temperatures of ductile blends yielded a marked decrease of both stress at rupture σ R and extension ratio at rupture λ R . © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2528–2537, 2004