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Polyurethane networks from formiated soy polyols: Synthesis and mechanical characterization
Author(s) -
Monteavaro Luciane L.,
Silva Eduardo O.,
Costa Ana Paula O.,
Samios Dimitrios,
Gerbase Annelise E.,
Petzhold Cesar L.
Publication year - 2005
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/s11746-005-1079-0
Subject(s) - polyurethane , curing (chemistry) , shore durometer , glass transition , castor oil , materials science , soybean oil , prepolymer , epoxy , swelling , polymer chemistry , polymer , chemical modification , hydroxyl value , vegetable oil , chemical engineering , polyol , organic chemistry , composite material , chemistry , food science , engineering
Polyurethanes can be prepared using polyols obtained from vegetable oils in natura , such as castor oil, or from functionalized vegetable oils, such as hydroxylated soybean oil. These polyurethanes have different valuable properties, determined by their chemical composition and cross‐linking density. In this study, soy epoxy polyols with different OH contents were prepared through a one‐step reaction using the method of in situ performic acid generation. Polyols with OH functionalities from 1.9 to 3.2 were reacted in bulk with different diisocyanates at a NCO/OH molar ratio of 0.8 and 60°C for 24 h. Mechanical properties of the polyurethanes were determined by dynamic mechanical thermal analysis, hardness (Shore A), and swelling measurements. Polymer networks with glass‐transition temperatures ( T g ) from −13 to 48°C were obtained. We observed that the higher the OH functionality of the polyols, the higher the T g and cross‐linking density of the polyurethane network. The influence of diisocyanate structure (rigid or flexible chain), curing temperature, and curing reaction time on mechanical properties was also investigated.