Document Detail


Enhancing the functionality of biobased polyester coating resins through modification with citric acid.
MedLine Citation:
PMID:  17994697     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Citric acid (CA) was evaluated as a functionality-enhancing monomer in biobased polyesters suitable for coating applications. Model reactions of CA with several primary and secondary alcohols and diols, including the 1,4:3,6-dianhydrohexitols, revealed that titanium(IV) n-butoxide catalyzed esterification reactions involving these compounds proceed at relatively low temperatures, often via anhydride intermediates. Interestingly, the facile anhydride formation from CA at temperatures around CA's melting temperature ( T m = 153 degrees C) proved to be crucial in modifying sterically hindered secondary hydroxyl end groups. OH-functional polyesters were reacted with CA in the melt between 150 and 165 degrees C, yielding slightly branched carboxylic acid functional materials with strongly enhanced functionality. The acid/epoxy curing reaction of the acid-functional polymers was simulated with a monofunctional glycidyl ether. Finally, the CA-modified polyesters were applied as coatings, using conventional cross-linking agents. The formulations showed rapid curing, resulting in chemically and mechanically stable coatings. These results demonstrate that citric acid can be applied in a new way, making use of its anhydride formation to functionalize OH-functional polyesters, which is an important new step toward fully biobased coating systems.
Authors:
Bart A J Noordover; Robbert Duchateau; Rolf A T M van Benthem; Weihua Ming; Cor E Koning
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't     Date:  2007-11-10
Journal Detail:
Title:  Biomacromolecules     Volume:  8     ISSN:  1526-4602     ISO Abbreviation:  Biomacromolecules     Publication Date:  2007 Dec 
Date Detail:
Created Date:  2007-12-11     Completed Date:  2008-02-28     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100892849     Medline TA:  Biomacromolecules     Country:  United States    
Other Details:
Languages:  eng     Pagination:  3860-70     Citation Subset:  IM    
Affiliation:
Laboratory of Polymer Chemistry, Eindhoven University of Technology, Den Dolech 2, 5600 MB Eindhoven, The Netherlands.
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MeSH Terms
Descriptor/Qualifier:
Citric Acid / chemical synthesis*
Coated Materials, Biocompatible / chemical synthesis*
Polyesters / chemical synthesis*
Resins, Synthetic / chemical synthesis*
Chemical
Reg. No./Substance:
0/Coated Materials, Biocompatible; 0/Polyesters; 0/Resins, Synthetic; 77-92-9/Citric Acid

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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