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Highly functional lactic acid ring‐opened soybean polyols applied to rigid polyurethane foams
Author(s) -
Herrán Rodrigo,
Amalvy Javier Ignacio,
Chiacchiarelli Leonel Matías
Publication year - 2019
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.47959
Subject(s) - polyurethane , differential scanning calorimetry , thermogravimetric analysis , materials science , epoxidized soybean oil , soybean oil , compressive strength , lactic acid , yield (engineering) , scanning electron microscope , polymer chemistry , dynamic mechanical analysis , chemical engineering , composite material , nuclear chemistry , polymer , chemistry , organic chemistry , raw material , physics , food science , genetics , biology , bacteria , thermodynamics , engineering
We synthesized polyols with high hydroxyl functionalities ( F OH s), between 9.0 and 12.6, and characterized them with differential scanning calorimetry, thermogravimetric analysis, and size exclusion chromatography after we parametrically studied the ring‐opening reaction of epoxidized soybean oil with lactic acid (LA) as a function of the reaction temperature and lactic acid equivalent fraction ( f LA ). An increase of only 20°C in the reaction temperature (from 80 to 100°C) caused changes in the hydroxyl number (+17.8%), F OH (–25%), viscosity (–14.0%), and oligomeric content (–24.1%). f LA mostly affected the ring‐opening yield, and only for f LA values above 0.4 was possible to achieve values higher than 80%. Rigid polyurethane foams (rPUFs) were synthesized and characterized with scanning electron microscopy, dynamic mechanical analysis (DMA), and compressive mechanical tests. rPUFs with a very high specific compressive strength (7.8 kPa kg –1 m 3 ) were synthesized solely with biobased soybean oil. DMA revealed a compromised relationship between the specific compressive strength and its temperature dependence. To increase the first one, the most relevant method was to increase F OH . Instead, to increase the latter one, the OH number had to be maximized. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47959.