Branched poly(lactide) synthesized by enzymatic polymerization: effects of molecular branches and stereochemistry on enzymatic degradation and alkaline hydrolysis.

Branched poly(lactide) synthesized by enzymatic polymerization: effects of molecular branches and stereochemistry on enzymatic degradation and alkaline hydrolysis. Research Abstract Details 

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Branched poly(lactide) synthesized by enzymatic polymerization: effects of molecular branches and stereochemistry on enzymatic degradation and alkaline hydrolysis. Abstract Text:

Keiji Numata,Rajiv K Srivastava,Anna Finne-Wistrand,Ann-Christine Albertsson,Yoshiharu Doi,Hideki Abe,Keiji Numata,Rajiv K Srivastava,Anna Finne-Wistrand,Ann-Christine Albertsson,Yoshiharu Doi,Hideki Abe,Keiji Numata,Rajiv K Srivastava,Anna Finne-Wistrand,Ann-Christine Albertsson,Yoshiharu Doi,Hideki Abe,

In this article the effects of the number of molecular branches (chain ends) and the stereochemistry of poly(lactide)s (PLAs) on the enzymatic degradation and alkaline hydrolysis are studied. Various linear and branched PLAs were synthesized using lipase PS (Pseudomonas fluorescens)-catalyzed ring-opening polymerization (ROP) of lactide monomers having different stereochemistries (L-lactide, D-lactide, and D,L-lactide). Five different alcohols were used as initiators for the ROP, and the monomer-to-initiator molar feed ratio was varied from 10 to 100 and 1000 for each branch in the polymer architecture. The properties of branched PLAs that would affect the enzymatic and alkaline degradations, i.e., the glass transition temperature, the melting temperature, the melting enthalpy, and the advancing contact angle, were determined. The PLA films were degraded using proteinase K or 1.0 M NaOH solution, and the weight loss and changes in the number average molecular weight (Mn) of the polymer were studied during 12 h of degradation. The results suggest that an increase in the number of molecular branches of branched PLAs enhances its enzymatic degradability and alkali hydrolyzability. Moreover, the change in Mn of the branched poly(L-lactide) (PLLA) by alkaline hydrolysis indicated that the decrease in Mn was in the first place dependent on the number of molecular branches and thereafter on the length of the molecular branch of branched PLA. The branched PLLA, poly(D-lactide) (PDLA), and poly(D,L-lactide) (PDLLA) differed in weight loss and change in Mn of the PLA segment during the enzymatic degradation. It is suggested that the branched PDLLA was degraded preferentially by proteinase K.

Branched poly(lactide) synthesized by enzymatic polymerization: effects of molecular branches and stereochemistry on enzymatic degradation and alkaline hydrolysis. Publishing Authors By Initials

K Numata,RK Srivastava,A Finne-Wistrand,AC Albertsson,Y Doi,H Abe,K Numata,RK Srivastava,A Finne-Wistrand,AC Albertsson,Y Doi,H Abe,K Numata,RK Srivastava,A Finne-Wistrand,AC Albertsson,Y Doi,H Abe,

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Branched poly(lactide) synthesized by enzymatic polymerization: effects of molecular branches and stereochemistry on enzymatic degradation and alkaline hydrolysis. Journal Published:

PUBLICATION TYPE: Research Support, Non-U.S. Gov

Journal: Biomacromolecules

VOLUME: 8

Page Numbers: 3115-25

Journal Abbreviation: Biomacromolecules

ISSN: 1525-7797

DAY: 28

MONTH: 08

YEAR: 2007

Branched poly(lactide) synthesized by enzymatic polymerization: effects of molecular branches and stereochemistry on enzymatic degradation and alkaline hydrolysis. Information

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LANGUAGE: eng

NlmUniqueID: 100892849

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Grant and Affiliation Information for Branched poly(lactide) synthesized by enzymatic polymerization: effects of molecular branches and stereochemistry on enzymatic degradation and alkaline hydrolysis.

AFFILIATION: Department of Innovative and Engineered Materials, Tokyo Institute of Technology, 4259 Nagatsuta, Yokohama, Japan.

Country: United States

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MEDLINETA: Biomacromolecules

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