Rigid polyurethane foams from unrefined crude
glycerol – Study of crude glycerol composition
N. V. Gama1, R. Silva2, C. S. R. Freire1, A. Barros-Timmons1, A. Ferreira3
1
CICECO - Aveiro Instituto de Materiais and Chemistry Department of University of Aveiro
2
3
Sapec-Química SA, Ovar, Portugal
CICECO - Aveiro Instituto de Materiais and Escola Superior de Tecnologia e Gestão de Águeda
Outline
 Introduction
 What are polyurethanes;
 Main applications;
 Desirable properties of polyurethane foams;
 Renewable feedstocks.
 Experimental and results
 Polyols used;
 Preparation of foams;
 Characterization of foams.
 Main conclusions
2
Introduction
Experimental
Results
Final Remarks
Polyurethanes (PUs), also referred as urethanes, are polymers characterized by the urethane linkage. The
linkage is formed by the reaction of NCO groups of isocyanate with OH groups of the polyol.
Isocyanate
Polyol
Polyurethane
Polyurethanes (PUs) are a class of polymers that find several important applications such:
Adhesives
Elastomers
Paints
Foams
3
Introduction
Experimental
Results
Final Remarks
Polyurethane foams (PUFs) are a class of lightweight porous materials with enormous interest due to their
specific properties and potential application.
Flexible foams
Rigid foams
Low thermal
conductivity
Low density
Good
mechanical
properties
Good thermal
resistance
4
Introduction
Experimental
Results
Final Remarks
The production of PUs depends significantly on fossil reactants. The use of renewable reagents, in
particular the replacement of the polyol, is increasing by the use of:
Vegetable oils
Biomass resources
Industrial by-products
Nuno V Gama, Belinda Soares, Carmen SR Freire, Rui Silva, Inês Brandão, C Pascoal Neto, Ana Barros-Timmons and Artur Ferreira. Polym. Int. 2015, 64, 250-257.
Gama, N. V.; Soares, B.; Freire, C. S. R.; Silva, R.; Neto, C. P.; Barros-Timmons, A.; Ferreira, A. Mater. Des. 2015, 76, 77–85.
Ferreira A.; Gama, N. V.; Soares, B.; Freire, C. S. R.; Barros-Timmons, A.; Brandão, I.; Silva, R.; Neto, C. P. ; Method for production of rigid polyurethane foams using unrefined crude glycerol. 107711 E, 2014
5
Introduction
Experimental
Results
Final Remarks
. The successful replacement of petrochemicals by CG in the PUFs production has the potential to reduce
their cost and environmental impact.
The composition of CG may vary in:
 Glycerol;
 Fatty acids;
 Methyl esters;
 Methanol;
 Water content.
6
Introduction
Experimental
Results
Final Remarks
CGA
CGT
84.1% (w/w) of glycerol,
10.0% (w/w) of fatty acids,
5.9% (w/w) of methyl esters,
98.2% (w/w) of glycerol,
0.6% (w/w) of fatty acids,
1.2% (w/w) of methyl esters,
Mw = 154.4 g/mol,
Water content = 1.6% (w/w),
OHnumber =399.0 mgKOH/g.
Mw of 97.8 g/mol,
Water content = 1.6% (w/w),
OHnumber = 497.7 mgKOH/g.
150 ºC, 60 min
4% (w/w) of sulfuric acid
In a 70L pilot reactor
CGB
60.1% (w/w) of glycerol,
21.3% (w/w) of fatty acids,
18.6% (w/w) of methyl esters,
Mw = 163.8 g/mol,
Water content = 0.4% (w/w),
OHnumber = 323.4 mgKOH/g.
GLY
99.5% purity,
Mw = 92.1 g/mol,
Water content = 0.1% (w/w),
OHnumber = 520.9 mgKOH/g.
7
Introduction
Experimental
Results
Final Remarks
Crude Glycerol
Isocyanate
Catalyst
Surfactant
Polyurethane foam
Blowing agent
8
Introduction
Experimental
Results
Final Remarks
Isocyanate used with a 20% of excess over
the polyols.
The methyl esters contributed to the
presence of residual NCO groups.
9
Introduction
Experimental
Results
Final Remarks
The fatty acids and methyl esters affect the
foaming process and the foam structure.
PUF-CGA
PUF-CGB
PUF
PUF-CGA
PUF-CGB
PUF-CGT
PUF-GLY
Density
3
(kg/m )
43.0
37.5
48.7
49.9
±
±
±
±
1.2
1.9
1.9
1.3
Thermal conductivity
(W/mk)
0.033
0.032
0.036
0.037
±
±
±
±
0.001
0.002
0.001
0.001
Reference k value for PUFs - 0.033 W/mk
PUF-CGT
PUF-GLY
Hu, S. & Li, Y. Polyols and polyurethane foams from acid-catalyzed biomass liquefaction by crude glycerol: Effects of crude glycerol impurities. Ind. Crops Prod. 57, 188–194 (2014).
10
Introduction
Experimental
Results
PUF
PUF-CGA
PUF-CGB
PUF-CGT
PUF-GLY
Final Remarks
Young
Compressive
Toughness (J/m3 )
modulus (kPa)
stress 10% (kPa)
617.7
539.9
680.1
699.5
±
±
±
±
12.4
18.7
19.1
26.1
1531.3
831.3
1930.0
2080.0
±
±
±
±
266.9
120.9
235.2
1752.0
44.9
36.6
50.5
53.3
±
±
±
±
3.4
1.8
3.8
3.1
The presence of fatty acids and methyl esters decreases the
mechanical properties of PUFs.
The higher OHnumber polyols leads to an increase of the
chemical cross linkage density.
The density, the morphology, the size or shape of the cells,
plays a significant role in the mechanical properties of the
foams.
Hu, S. & Li, Y. Polyols and polyurethane foams from acid-catalyzed biomass liquefaction by crude glycerol: Effects of crude glycerol impurities. Ind. Crops Prod. 57, 188–194 (2014).
Shufen, L., Zhi, J., Kaijun, Y., Shuqin, Y. & Chow, W. K. Studies on the Thermal Behavior of Polyurethanes. Polym. Plast. Technol. Eng. 45, 95–108 (2006).
11
Introduction
Experimental
Results
Final Remarks
PUF
Storage
modulus (Pa)
Tg ( C)
PUF-CGA
PUF-CGB
PUF-CGT
PUF-GLY
4.62E+05
3.80E+05
1.25E+06
1.06E+06
166.1
157.7
168.3
173.0
o
The presence of fatty acids and methyl esters decreases the
mechanical properties of PUFs.
The higher OHnumber polyols leads to an increase of the
chemical cross linkage density.
The density, the morphology, the size or shape of the cells,
plays a significant role in the mechanical properties of the
foams.
Hu, S. & Li, Y. Polyols and polyurethane foams from acid-catalyzed biomass liquefaction by crude glycerol: Effects of crude glycerol impurities. Ind. Crops Prod. 57, 188–194 (2014).
Shufen, L., Zhi, J., Kaijun, Y., Shuqin, Y. & Chow, W. K. Studies on the Thermal Behavior of Polyurethanes. Polym. Plast. Technol. Eng. 45, 95–108 (2006).
12
Introduction
Experimental
Results
Final Remarks
The 20% of mass loss:
PUF-CGA → T = 252.5 oC
PUF-CGB → T = 240.4 oC
PUF-CGT → T = 257.0 oC
PUF-GLY → T = 262.6 oC
Foams thermally stable up to 180 ºC
Soft segments
Hard segments
13
Introduction
Experimental
Results
Final Remarks
 The crude glycerol foams presented:
 Low thermal conductivity;
 Low density;
 Good mechanical properties;
 The crude glycerol foams are thermally stable up to 180 ºC
 The presence of fatty acids and methyl esters in the CG has the effect of:
 Decreases the density of the foams;
 Decreases the thermal conductivity of the foams;
 Decreases the mechanical properties of the foams;
 Decreases the Tgs of the foams;
 Decreases the thermal stability of the foams.
Crude Glycerol, without any purification step or pre-treatment, is a renewable and a
suitable ecopolyol for the production of PUFs
14
ACKNOWLEDGMENTS
Financial Support
GREENPEC – FCOMP-01-0124-FEDER-34132
This work was developed in the scope of the project CICECO-Aveiro Institute of Materials, financed by national funds through
the FCT/MEC and when applicable co-financed by FEDER under the PT2020 Partnership Agreement