Stereocomplex Formation between Enantiomeric Substituted Poly(lactide)s: Blends of Poly[(<i>S</i>)-2-hydroxybutyrate] and Poly[(<i>R</i>)-2-hydroxybutyrate]

Tsuji, Hideto; Okumura, Ayaka

doi:10.1021/ma9015483

Cited by 72 publications

(118 citation statements)

References 27 publications

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“…Before hydrolytic degradation, pure P(L-2HB) and P(D-2HB) had intense crystalline diffraction peaks at around 151 and 171, whereas the P(L-2HB)/P(D-2HB) blend exhibited no such peaks for pure P(L-2HB) and P(D-2HB), with the exception of new crystalline peaks at around 111, 181 and 221, which are ascribed to stereocomplex crystalline peaks. 21 After hydrolytic degradation, the specimens had crystalline peaks at the diffraction angles identical to those of the specimens before hydrolytic degradation. These findings reflect that the crystalline species were not altered by the hydrolytic degradation, and, therefore, the P(L-2HB)/P(D-2HB) blend contained only stereocomplex crystallites as crystalline species during hydrolytic degradation.…”

Section: Hydrolytic Degradationmentioning

confidence: 84%

“…P(L-2HB) and P(D-2HB) were synthesized by the polycondensation of (S)-and (R)-2-hydroxybutanoic acids (2-hydroxybutyric acids) (X97.0%, enantiomeric ratio X99:1, Sigma-Aldrich (Tokyo, Japan)), respectively, 24 following which purification and drying 21,25 were carried out according to previous literature. The specimens (thickness of ca.…”

Section: Materials and Methods Materialsmentioning

confidence: 99%

“…50 mm) used for the crystallization and hydrolytic and thermal degradation experiments were prepared according to the literature. 21 Each solution of the purified and dried P(L-2HB) and P(D-2HB) was separately prepared with dichloromethane as the solvent to obtain a polymer concentration of 1 g dl À1 . For the preparation of P(L-2HB)/P(D-2HB) blend specimens, the P(L-2HB) and P(D-2HB) solutions were mixed with each other equimolarly under vigorous stirring.…”

Section: Materials and Methods Materialsmentioning

confidence: 99%

“…A stereocomplex can also be formed by blending substituted enantiomeric PLAs, that is, poly(L-2-hydroxybutyrate) [P(L-2HB)] and poly(D-2-hydroxybutyrate) (P (D-2HB)). 21 The melting temperature (T m ) of the P(L-2HB)/P(D-2HB) stereocomplex (ca. 200 1C) is higher than those of pure P(L-2HB) and P(D-2HB) (ca.…”

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confidence: 99%

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Crystallization and hydrolytic/thermal degradation of a novel stereocomplexationable blend of poly(L-2-hydroxybutyrate) and poly(D-2-hydroxybutyrate)

Tsuji

Okumura

2010

Polym J

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The maximum radial growth rate of spherulites of the novel stereocomplexationable blend of poly(L-2-hydroxybutyrate) (P(L-2HB)) and poly(D-2-hydroxybutyrate) (P(D-2HB)) was observed to be substantially higher than those of pure P(L-2HB) and P(D-2HB). The hydrolytic degradation rate of the P(L-2HB)/P(D-2HB) blend traced by gravimetry and gel permeation chromatography was significantly lower than those of pure P(L-2HB) and P(D-2HB); this indicated that the blend had higher resistance to hydrolytic degradation. Further, the thermal degradation rate of the P(L-2HB)/P(D-2HB) blend was retarded as compared with those of pure P(L-2HB) and P(D-2HB). The results obtained in the present study indicate that the intermolecular interaction between P(L-2HB) and P(D-2HB) chains having opposite configurations in the amorphous regions or in the molten state was higher than that between P(L-2HB) or P(D-2HB) chains with the same configurations. The information obtained in the present study should be very useful for designing and processing pure, biodegradable materials of P(L-2HB), P(D-2HB) and their blends for biomedical, pharmaceutical and environmental applications. Keywords: crystallization; hydrolytic degradation; poly(hydroxybutanoic acid); poly(hydroxybutyric acid); stereocomplex; thermal degradation INTRODUCTION Poly(L-lactide) (that is, poly(L-lactic acid) or PLLA) is a biodegradable polymer produced from plant-derived renewable resources and is now used for biomedical, pharmaceutical, environmental, industrial and commercial applications. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] Stereocomplexation between PLLA and its enantiomer poly(D-lactide) (that is, poly(D-lactic acid) or PDLA) can yield biodegradable materials having superior mechanical performance and resistance to hydrolytic and thermal degradation relative to pure PLLA and PDLA. [16][17][18][19][20] Poly(2-hydroxybutyrate) (that is, poly(2-hydroxybutanoic acid) or P(2HB)) is a biodegradable polymer with the structure of a poly(lactide) (that is, poly(lactic acid) or PLA) in which methyl groups are substituted with ethyl groups. A stereocomplex can also be formed by blending substituted enantiomeric PLAs, that is, poly(L-2-hydroxybutyrate) [P(L-2HB)] and poly(D-2-hydroxybutyrate) (P (D-2HB)). 21 The melting temperature (T m ) of the P(L-2HB)/P(D-2HB) stereocomplex (ca. 200 1C) is higher than those of pure P(L-2HB) and P(D-2HB) (ca. 100 1C). The spherulite growth or crystallization of the P(L-2HB)/ P(D-2HB) stereocomplex is completed in a substantially shorter period of time as compared with those of pure P(L-2HB) and P(D-2HB). From the results reported for PLLA/PDLA blends, [16][17][18][19][20] it is expected that the resistance of P(L-2HB)/P(D-2HB) blends to hydrolytic and

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Section: Hydrolytic Degradationmentioning

confidence: 84%

Section: Materials and Methods Materialsmentioning

confidence: 99%

Section: Materials and Methods Materialsmentioning

confidence: 99%

mentioning

confidence: 99%

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Crystallization and hydrolytic/thermal degradation of a novel stereocomplexationable blend of poly(L-2-hydroxybutyrate) and poly(D-2-hydroxybutyrate)

Tsuji

Okumura

2010

Polym J

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“…Tsuji et al [141] synthesized poly[(S)-2-hydroxybutyrate] [P(S-2HB)] and R-configured PDLA and prepared solution and melt-crystallized blends from them. They reported heterostereocomplexationability of these blends and analyzed them by DSC, WAXS, and polarized optical microscopy (POM).…”

Section: Family Of Polyhydroxyalkanoate/pla Blendsmentioning

confidence: 99%