June 2011
Griselda Barrera Galland
Universidade Federal do Rio Grande do Sul – UFRGS Instituto de Química
Laboratório de Catálise Ziegler-Natta
CHALLENGES ON THE SYNTHESIS AND CHARACTERIZATION OF
POLYOLEFINS
PORTO ALEGRE, RIO GRANDE DO SUL, BRAZIL
PORTO ALEGRE, RIO GRANDE DO SUL
UFRGS
UNIVERSIDADE FEDERAL DO RIO GRANDE DO SUL UFRGS
Students • Under-graduated (75%) 24.707 • Graduation (25%) 8.415
Master 4.694 Ph D 3.290 Profissional Master 431 33.122
Professors 2.247 Staff 2.460
INSTITUTO DE QUÍMICA
(CHEMICAL INSTITUTE) -UFRGS
Bacharelado em Química (BS in Chemistry)
Química Industrial (Industrial Chemist)
Licenciatura em Química (Degree in Chemistry)
Tecnólogo em Química (Chemical Technologist)
Under-graduated studies:
Graduated studies:
Master degree
Doctorate degree
Professors: 84
Students: undergraduated (470), graduated (161)
Staff: 44
Elementar Analysis (CHN) Nitrogen Adsorption Analysis
Micrometrics Tristar® II 3020
- Gas Chromatograph with Flame Ionization Detector, Varian 3400 - Gas Chromatograph with Electron Capture Detector, Varian 3400 - Gas Chromatograph with Flame Ionization, Shimadzu
Chromatographs
- Light Scattering Spectrophotometer Brookhaven Instruments (BI) 9000
Fluorimeter
- Infrared Spectrophotometer (FTIR) Shimadzu Prestige-21
- High Resolution Mass Spectrometer Micromass QTOF Waters 3200
Shimadzu, model UV1601PC
Ultraviolet Spectrophotometer (UV)
Chemistry Institute Facilities
Nuclear Magnetic Resonance Laboratory
Varian Inova e Varian VNMRs operating at 300MHz 1H, 13C, 31P, 15N, 17O
-DSCQ2000 + RCS90 – Differential Scanning Calorimeter; - AutoDSCQ20 + RCS40 – Differential Scanning Calorimeter; - TGAQ5000IR – Thermogravimetric Analyzer; - SDTQ600 (TGA-DTA-DSC Simultaneous); - DMAQ800 – Dynamic Mechanic Analyzer; - TGA2050 - Thermogravimetric Analyzer; - DSC2010 + RCS and Gas Chromatograph/mass spectrometer(CG-MS) Shimatzu model QP 2010 with interface for TGA – Thermogravimetric Analyzer. - DSC 4, Perkin Elmer, temperature range: -40 to 400 0C - DSC 2910, DuPont, temperature range: -150 to 400 0C - Melt Index, Ceast Junior
Thermal Analysis Sector
- Scanning Electronic Microcope JEOL JSM 5800 - Scanning Electronic Microcope JEOL JSM 6060 - Transmission Electronic Microcope JEOL JEM 1200FxII - Transmission Electronic Microcope JEOL JEM 2010 - X Ray Diffraction Phillips – X´Pert MRD - Confocal Fluorescence Microscope OLYMPUS
Electronic Microscopy Center
SYNTHESIS OF NEW
POST-METALLOCENE
CATALYSTS FOR OLEFIN
POLYMERIZATION
PYRONE COMPLEXES (Maltol Derivates)
Sobota, P.; Przybylak, K.; Utko, J.; Jerzykievicz, L.B.; Pombeiro, A.J.L.; Silva, M.F.G.; Szczegot, K. Chem Eur. J. 2001, 7, 951-958.
Carone, C., De Lima, V.; Albuquerque, F.; Nunes, P.; de Lemos, C.; Dos Santos, J.H.Z.; Galland, G.B.; Stedile, F.C.; Einloft, S.; Basso, N.R.S. J. Molecular Catalysis A: Chem. 2004, 208, 285-290.
Fim, F.C.; Machado, T.; De Sá, D.S.; Livotto, P.R.; Da Rocha, Z.N.; Basso, N.R.S.; Galland, G.B. J. Polym. Sci.: Part A: Polym. Chem., 2008, 46, 3830-3841.
O
O
O
R
M
ClCl
O
OR
OMCl4/THF
M=Ti, ZrO
OOH
R
R= Me, Et
1 2 3 430 C
40 C60 C
0
100
200
300
400
500
Cat
alyt
ic A
ctiv
ities
(K
gPE/
nM.h
.atm
)
1 R=Me; M=Ti
3 R=Me; M=Zr
2 R=Et; M=Ti
4 R=Et; M=Zr
[Zr] = 1µmol Al/Zr = 2500 Cocatalyst=MAO PE = 1.6atm time=1h
O
O
O
R
M
ClCl
O
OR
O
O
O
O
O
OO
ClCl
Ti
[Ti] = 3 × 10-6 mol; MAO (Al/Ti = 1000); solvent: toluene; T = 40°C.
SUPPORTED
Greco, P.P.; Brambilla, R.; Einloft, S.; Stedile, F.C.; Galland, G.B.; Dos Santos, J.H.Z.; Basso, N.R.S. J. Molecular Catalysis A: Chemical , 2005, 240, 61-66
O
O
O
OO
ClCl
Zr SUPPORTED
Zr] = 1x10-6; MAO (Al/Zr= 2500); solvent: toluene;
POLYOLEFIN
NANOCOMPOSITES
BY IN SITU POLYMERIZATION
CHRYSOTILE/POLYETHYLENE
NANOCOMPOSITES
Asbestos Serpentine Group
Amosite
Crocidolite
Antofilite Tremolite
Actinolite
Amphibole group
Chrysotile
Main asbestos mines in the world
Countries Production (m. ton.)
Russia 920.000
China 360.000
Brazil 290.000 Kazakhstan 210.000
Canada 200.000
Zimbabwe 130.000
Others 15.000
Total 2.125.000
http://www.sama.com.br/empresa/seguranca.htm
Chrysotile Characteristics
Main Chemical and Physic properties
Good Mechanical Resistance
Incombustibility
Electrical and Acoustic isolant
Good Chemical Resistance
Flexibility and durability
Thermal Stability No oxidation
Chrysotile
Structure:
Tetrahedral silica layer
+
Octahedral brucite layer
Nanotube
Quím. Nova vol.26 no.5 São Paulo Sept./Oct. 2003.
Fórmula: Mg3(Si2O5) (OH)4
Morphology: Fibrous
OH
Mg
OH
OH
Mg
OH
OH
Mg
OH
OH
Mg
OH
HO
O O
Si SiOOO O
Si
O
OSi
O O
O
Si
O
OAcid Leached0,1N HCl
Acid Leached 3M HCl
Thermal Treatment 800°C
OH
Mg
OH
OH
Mg
OH
OH
Mg
OH
OH
Mg
OH
HO
O O
Si SiOOO O
Si
O
OSi
O O
O
Si
O
O
Si SiOOO O
SiO
SiO O
SiO
OH OH OH OH OH
Mg
OH
Mg
OH
Mg
OH
Mg
OHO O
Si SiOOO O
Si
O
OSi
O O
O
Si
O
O
O O O O O
200°C
400°C
Si SiOOO O
SiO
SiO O
SiO
OHO O
OH
Mg
OH
OH
Mg
OH
OH
Mg
OH
OH
Mg
OH
HO
O O
Si SiOOO O
Si
O
OSi
O O
O
Si
O
O
O O
Neat Chrysotile
CHRYSOTILE SURFACE TREATMENTS
METHOD A
METHOD C
METHOD B
Transmission Electron Microscopy images of the samples of (a) neat chrysotile, (b) chrysotile modified by the acid treatment 0.1N HCl, (c) chrysotile modified by the acid treatment 3M HCl and (d) chrysotile after thermal treatment.
Mg/Si ratio of the neat and treated chrysotile. Neat
Chrysotile
Chyisotile treat. 0. 1 N
Chrysotile treat. 3M
Chrysotile thermal treat.
Ratio Mg/Si
1.07 0.80 0.0017 1.16
X RAY DIFFRACTION (XRD) OF CHRYSOTILE AND NANOCOMPOSITES
Neat chrysotile Chrysotile modified by the acid treatment 0.1N HCl
Chrysotile modified by the acid treatment 3M HCl Chrysotile after thermal
treatment at 800 C
Amorphous Silica Fosterite Mg2SiO4 Structure
Method Theoretical percentage
of the chrysotile
(%)
Experimental percentage of the chrysotile
(%)
Weight of the
polymer(g)
neat PE 0.0 0.0 6.72 A 1.0 1.72 3.48 B 1.0 0.59 10.07 C 1.0 1.67 3.44
METHOD A:
CHRYSOTILE SUPPORTED ON C2ZrCl2/MAO
METHOD B:
TREATED CHRYSOTILE ADDED DIRECTLY INTO THE REACTOR
METHOD C:
THERMAL TREATED CHRYSOTILE SUPPORTED OVER THE CATALYST.
IN SITU POLYMERIZATION OF PE/CHRYSOTILE NANOCOMPOSITES
Neat polyethylene PE/chrysotile nanocomposite with chrysotile treated with 0.1NHCl
PE/chrysotile nanocomposite with chrysotile treated with 3M HCl
PE/chrysotile nanocomposite with chrysotile treated at 800oC.
SEM images of Polyethylene nanocomposites
ETHYLENE/CHRYSOTILE NANOCOMPOSITES
450
460
470
480
490
500
0 2 4 6 8 10 12
% Chrysotile
Ethy
lene
Deg
rada
tion
Tem
pera
ture
(o C
)
DEGRADATION TEMPERATURE OF PE INCREASED WITH THE AMOUNT OF CHRYSOTILE IN THE NANOCOMPOSITE
MECHANICAL PROPERTIES
POLYETHYLENE BECAME MORE ELASTOMERIC WITH THE INCREASE OF THE AMOUNT OF CHRYSOTILE.
PARCIAL CONCLUSIONS
IT IS POSSIBLE TO OBTAIN POLYETHYLENE/CHRYSOTILE NANOCOMPOSITES BY IN SITU POLYMERIZATION USING METALLOCENE CATALYSTS WITH GOOD ACTIVITIES
THE NANOCOMPOSITES HAVE BETTER THERMAL STABILITY THAN POLYETHYLENE
NANOCOMPOSITES ARE MORE ELASTOMERIC THAN POLYETHYLENE
GRAPHITE / POLYETHYLENE NANOCOMPOSITES
GRAPHITE: CHEMICALLY INERT
HEAT-RESISTANT
ELECTRICAL CONDUCTIVITY
THERMAL CONDUCTIVITY
POLYETHYLENE: HIGH INSULATING PROPERTIES
HIGH DUCTILITY
GOOD PROCESSABILITY
TO LOAD AN INSULATING POLYMER WITH AN ELECTRICALLY CONDUCTING FILLER SHOULD INCREASE THE RANGE OF APPLICATIONS OF PE
APPLICATIONS:
ELECTROMAGNETIC RADIATION SHIELDING
PREVENTION OF CROWN DISCHARGE IN HIGH VOLTAGE CABLES
LOW-TEMPERATURE HEATERS
TRANSDUCERS
PREPARATION OF NANOCOMPOSITES
Melt processing Solvent processing In situ polymerization
Potts, J. R., Dreyer, D. R., Bielawski, C. W., Ruoff, R. S., Polymer, 2011, 52, 5.
MELT PROCESSING
Direct inclusion of the nanofiller into the melted polymer using an extruder.
LLDPE/GNS – Kim, S.; Do, I.; Drzal, L.T. Macromolecular Materials and Engineering 2009, 294, 196-205
HDPE/EG composites - Li, Y. C.; Chen, G. H. Polym Eng Sci 2007, 47,
882-888. iPP/GNS – Polypropylene: Steurer, P.; Wissert, R.; Thomann, R.;
Mulhaupt, R.,Macromol. Rapid Commun., 2009, 30, 316-327.
iPP/GNS – Polypropylene: Kalaitzidou, K.; Fukushima, H.; Drzal, L. T. Composites, Part A 2007, 38, 1675-1682.
SOLVENT PROCESSING
Dispersion of the nanofiller in a suitable solvent, addition of the polymer and removal of the solvent.
HDPE/GNS: Du, J.; Zhao, L.; Zeng, Y.; Zhang, L.; Li, F.; Liu, P. Carbon 2011, 49, 1094-1100.
UHMWPE/GNS: Pang, H.; Chen, T.; Zhang, G.; Zeng, B.; Li, Z-M. Material Letters 2010, 64, 2226-2229.
LDPE/Functionalized Graphene: Wang, J.; Xu, C.; Hu, H.; Wan, L.; Chen, R.; Zheng, H.; Liu, F.; Zhang, M.; Shang, X.; Wang, X. J. Nanopart Res 2011, 13, 869-878.
IN SITU POLYMERIZATION
The nanofillers are mixed with the monomer in the presence of a solvent and then the polymerization reaction proceeds to make
the nanocomposite.
HDPE – High Density Polyethylene: Fim, F. C., Guterres, J. M., Basso, N. R.. S., Galland, G. B., J. Polymer Science, Part A: Polymer Chemistry, 2010, 48, 692.
PP – Polypropylene: Montagna, L.S., Fim, F. C., Galland, G. B., Basso, N. R.. S. Macromolecular Symposia, 2011,299, 48.
Monomer of the a-olefin
Exfoliated nanocomposite
Nanofiller with lamelar structure
CRYSTALINE STRUCTURE OF GRAPHITE
basal plane
Covalent bond
Van der Waals forces
- Layer - Anisotropic
GRAPHENE
PREPARATION OF THE GRAPHENE NANOSHEETS (GNS)
H2SO4/HNO3
1000°C ultrason
(a) Natural graphite flake
(b) Intercalated graphite flake
(c) Expanded graphite (d) Graphite after the ultrason treatment
Sample 2θ (°)
d002 (nm)
C (nm)
Graphite Flake 26.67 0.333 58.38
GNS 26.52 0.336 28.15
Bragg’s Law:
θβλ
cos9,0
=C
θλ dsen2=
Scherrer’s Eq.:
STRUCTURE OF GRAPHITE CRYSTAL - XRD
16 24 32
0
400000
Inten
sity
2θ
Graphite flake
GNS
(002)
GRAPHENE NANOSHEETS- TEM
10 nm
200 nm
SYNTHESIS OF THE NANOCOMPOSITES BY IN SITU POLYMERIZATION
do banho
1 10 2 3
4 5 6 7
8
9 1 10
2
3
45 6
7
8
9
controller of temperature and
stirring
2.8 bar of ethylene pressure
Cocatalyst MAO - Al/Zr = 1000
Cp2ZrCl2 –
2 µmol of Zr
graphite treated
with MAO
PARR Reactor
To prevent the metallocene from being deactivated by the functional groups at the
graphene surface.
NANOCOMPOSITES NANOMETRIC - TEM
6.6 wt.% GNS
5.4 wt.% GNS
THERMAL PROPERTIES – DSC and TGA
SAMPLE (vol.%)
Tm
( C)
Xc
(%)
Tonset (°C)
Tmax (°C)
Neat PE 132 74 442±1 480±2
PE/1.4% GNS 132 68 454±1 487±1
PE/5.4% GNS 131 84 471±1 494±2
PE/6.6% GNS 131 71 472±1 495±1
PE/15.3% GNS 131 59 463±1 510±1
0 2 4 6 8 10 12 14 16
480
485
490
495
500
505
510
Degr
adati
on T
empe
ratu
re (o C)
Graphite Content (wt.%)
Increase of thermal stability
DYNAMIC MECHANICAL PROPERTIES
Storage Modulus Mechanical Damping
Storage modulus is similar to stiffness
Sample Tg (°C)
Neat PE -119
PE/1.4% GNS -108
PE/5.4% GNS -108
PE/6.6% GNS -107
-150 -100 -50 0 50 100 1500
500
1000
1500
2000
2500
3000 Neat PE PE/1.4% GNS PE/5.4% GNS PE/6.6% GNS
E' (M
Pa)
Temperature (oC)
-150 -100 -50 0 50 100 150
0,05
0,10
0,15
0,20
0,25
0,30 Neat PE PE/1.4% GNS PE/5.4% GNS PE/6.6% GNS
Tan
Delta
Temperature (oC)
MECHANICAL PROPERTIES
Tensile Strength E = σ/ε
0 1 2 3 4 5 6 7
0
50
100
150
200
250
300
Elon
gatio
n at
brea
k (%
)
GNS Content (wt.%)
0 1 2 3 4 5 6 7520530540550560570580
Elas
tic M
odul
us (M
Pa)
GNS Content (wt.%)
0 10 20 30 400
5
10
15
20
25
Neat PE PE/1.4% GNS PE/5.4% GNS PE/6.6% GNSSt
ress
(MPa
)
Strain (%)
MORPHOLOGY OF FRACTURE SURFACES
A C
B F
E
D
SEM images tensile broken section in the same magnification of A) neat polyethylene, B) PE/1.4% GNS, C) PE/5.4% GNS, D) PE/6.6% GNS; and
in a greater magnification: E) PE/5.4% GNS and F) PE/6.6% GNS.
0 2 4 6 8 10 12 14 160
10x10-13
2x10-12
3x10-121x10-8
2x10-8
3x10-8
Elec
trica
l Con
ducti
vity
(Ohm
-1. c
m-1)
Graphite Content (wt.%)
insulating
semiconductor
ELECTRICAL PROPERTIES – IMPEDANCE SPECTROSCOPY
NUCLEAR MAGNETIC RESONANCE
APPLIED TO POLYOLEFINS
13C NMR applied to polymers
Advantages:
Chemical shifts are spread in 200 ppm while 1H are concentrated in 10 ppm
Spectra are simpler due to the inexistence of couplings
Limitations:
Less sensible than 1H (lower magnetic moment (µ1H=2.29; µ13C=0.70) and natural abundance of the isotope (13C =1.1%).Sensibility & µ3, the carbon is less sensible than 1H in a fator of ~64.
It is not quantitative: special conditions of analyses are required
INTRODUCTION
PROBLEMS OF
QUANTITATIVE 13C NMR
ANALYSIS
Relaxation of nuclear spin
α → β energy absorption β → α energy relaxation
The spin population follows the Boltzmann distribution
Nα > Nβ NβNα
= exp(hυ/kT)
E
α
β
T1 relaxation spin-matriz
Quantitative analysis: Relaxation Delay=
5xT1 (α=90o)
Increase analysis times!
Differential relaxation times in 13C NMR Variations in the relaxation times of different carbons
CH2 CH2 CH2CH2CH2CH2 CH2 CH2
CH2
CH2
CH2
_ _ _ _CH CH3
CH3
___ __ (CH2)n ___
CH2
4,42,0
1,11,7
1,1
1,31,3 1,8 2,9
7
78
Ex.: Relaxation times (in sec) of a copolymer ethylene-1-hexene (97/3)
Solution:
•To use time delay 5T1: (ex.: 5x7=35s) VERY HIGH ANALYSIS TIMES
•To use paramagnetic substances (0.05M) Ex. Cr+3 Acetyl acetonate
It can broaden the spectrum
Pham, Quang Tho. Etude de la Microstructure des polymères par RMN 1H - 13C “Liquide”. Annales des Composites, Techniques Analytiques et Caractérisation des Materiaux Macromoléculaires, Paris 16 - 17, pp 49-69, décembre 1985.
Differential Nuclear Overhauser Effect
Secondary effect due to 13C-1H decoupling
Solution: Inversed Gated Decoupling
S/N increases until 3 times
Spectrum without NOE, without increased in sensibility!!!
Most of researchers prefer to use NOE
INFLUENCE OF NOE IN ETHYLENE-1-OCTENE COPOLYMER
13C NMR
NOE increases S/N in 1485/592=2.5 times and
reduces the analyses time in a factor of 629/100=6.3
Adriaensens, PJ., Karssenberg, F.G., Gelan, J.M., Mathot, V.B.F. Polymer 44, 3483-3489 (2003)
Entry NOE S/N ratio Time index
1 No 592 100 2 Yes 1485 100 3 No 1485 629
Time index of 100 correspond to an experimental time of about 2h40min (175 scans)
Using an integral precision of 90% instead of 100% it is possible to increase S/N 31%
It is possible to obtain an integral precision of 90% with a pulse angle of 74o and a pulse delay of 2xT1
Traficante, Daniel D, Concepts in Magnetic Resonance, 3, 13 - 26 (1991).
QUANTITATIVE 13C NMR ANALYSIS
INTRODUCTION
Solution NMR of polyolefins Additional problem
High temperatures of analysis (till 140oC)
Special Solvents
Solvent Boiling Point Vapor Pressure
1,1,2,2-tetrachloroethane-d2 145-146º C 400mm a 124.0o C
760mm a 145.9o C
1,2-dichlorobenzene 179-180º C 400mm 155.8o C
1,2,4-trichlorobenzene 214º C 100mm a 140o C
Benzene-d6 79.1o C 760 mm a 80.1oC
Dalton + Raoult Laws=
Ptotal = Pbenzene + Podcb = Pobenzene x 0.2 + Po
odcb x 0.80 =
760 x 0.2 + 400 x 0.8 = 472 mm
Temperature and Solvents
Sequence Percentage (mol%) Spectrum obtained at 90oC*
Spectrum obtained at 130oC*
Spectrum obtained at
140oC* (1600 scan)
Spectrum obtained at 140oC* (960 scan)
Spectrum obtained at
140oC (Solvent C2Cl4D2, 3968
scan) [PPP] 28,1 37,5 76,8 76,1 75,1 [EPP] 20,7 19,3 5,7 8,0 8,0 [EPE] 7,9 6,3 3,0 2,5 2,7 [EEE] 15,7 14,3 6,4 6,3 6,1 [PEP] 11,0 10,2 4,4 3,5 2,6 [PEE] 16,6 12,5 3,6 3,5 5,5 [P] 56,7 63,1 85,6 86,7 85,8 [E] 43,3 36,9 14,4 13,3 14,2
Influence of Temperature, Solvent and No of transients (EP high amount of P)
Robinson, Danieli. Trabalho de Conclusão, IQ-UFRGS, 07/2010
*Solvent: o-dichloro-benzene +20% C2Cl4D2
Type and amount of branches
Comonomer distribution in the polymer chain (sequences of
comonomers)
Determination of the regio and the stereorregurarity in
poly- α-olefins
Monomer reactivity ratios
Mecanism of the polymerization
INTRODUCTION
NUCLEAR MAGNETIC RESONANCE APPLIED TO POLYOLEFINS:
COPOLYMERS
RANDOM AAABAABBBABAABAA
BLOCK AAAAAAAAABBBBBBB
ALTERNATED ABABABABABABABAB
DIADS (XX, XY, YY)
CH2 CH CH2 CHX X
_ _X
CHCH2CHCH2 CH2 CH CH2 CH_
Y Y Y
XX XY YY
YX
_
XYCHCH2CHCH2 CH2 CH
YY
XX _XXCHCH2CHCH2 CH2 CH
YY
XXCHCH2CH2 CH CH2 CH
X X_XX
XYYXCHCHCH2 CH2 CH
XX
YYYYCHCH2CHCH2 CH2 CH
XX
YYCHCH2CH2 CH CH2 CH
Y Y_YY
_
_CH2
TRIADS
INTRODUCTION
STUDY OF BRANCHED POLYOLEFINS USING 13C NUCLEAR MAGNETIC RESONANCE
SPECTRUM
Chemical Shifts
Integrals
TRIADS EEE PPP EEP PPE PEP EPE
TRIAD: PEP
P P E
= CH2CH2 (ethylene)
= CH2CHCH3
(propylene)
TRIADS COMONOMER AVERAGE SEQUENCE LENGTH
-PEEEEEEP- -EPPPPPE-
nEP = [EEE] + [EEP+PEE] + [PEP] nPE = [PPP] + [EPP+PPE] + [EPE] [PEP] + ½ [EEP+PEE] [EPE] + ½ [EPP+PPE]
nEP =6 nPE =5
TRIADS
MONOMER REACTIVITY RATIOS
rEP = 2 [EE] rPE = 2 X1 [PP] X1 [EP] [PE]
being: [EE] = [EEE] + ½ [EEP + PEE] [PP] = [PPP] + ½ [EPP + PPE] [EP] = [PEP] + ½ [EEP + PEE] [PE] = [EPE] + ½ [EPP + PPE]
X1 = [E] / [P] in the feed
E* + E E*kEE
E* + P E*kEP
P* + E E*kPE
P* + P P*kPP
rEP= kEE/kEP rPE= kPP/kPE
13C NMR OF ETHYLENE-PROPYLENE-α-OLEFINS TERPOLYMERS
OBJETIVE
Determination of all chemical shifts
Quantitative determination of all comonomer sequences
Determination of reaction ratios
Determination of average comonomer sequence lengths
13C NMR OF COPOLYMERS
a) Ethene-propene copolymer, E = 64.7 mol%, P = 35.3 mol %
b) Propene-1-decene copolymer, P = 95.1 mol% D = 4.9 mol%;
c) Ethene-1-decene copolymer, E = 85.6 mol%, D = 14.4 mol %
d) 1-decene homopolymer,
ETHYLENE-PROPYLENE-1-DECENE
13C NMR spectra of Ethene-propene-1-decene terpolymers
E = 86.8 mol%, P = 6.3 mol %, D = 6.9
E = 67.7 mol%, P = 28.9 mol%, D = 3.4 mol%;
E = 12.8 mol%, P = 85.9 mol% D = 1.3 mol %
E = 4.4 mol%, P = 93.3 mol%, D = 2.3 mol%
peak no. chemical shift exp. (ppm)
chemical shift calc. (ppm)
triad assignments
9 24.30 25.08 DED ββΒ8 10 10a 10b 10c 10d
24.35-24-85 24.40 24..57 24.63 24.80
24.58 PEP PPEPP
EPEPE(m) PPEPE+EPEPP
EPEPE(r)
ββΒ1
DED
E = 28.9 mol%, P = 70.2 mol %, D = 0.9
E = 64.7 mol%, P = 35.3 mol%
E = 86.8 mol%, P = 6.3 mol% D = 6.9 mol %
E = 73.6 mol%, P = 9.0 mol%, D = 17.4 mol%
E = 85.6 mol%,D = 14.4 mol%
PPEPP
EPEPEm PPEPE+EPEPP
EPEPEr
Calculated and observed 13Carbon Chemical Shifts and Assignments for Ethylene-propylene and 1-decene Terpolymers
peak no.
chemical shift exp. (ppm)
chemical shift calc.
(ppm)
triad assignments
1 14.13 13.86 EDE EDD+DDE DDD PDP PDD+DDP 1Β8
2 19.40-20.30 19.58
20.61 PPP (rr) PPP(mrrm)
1Β1
3 19.87 19.63 EPE 1Β1
4 20.55 20.12 EPP+PPE 1Β1
5 20.30-21.00 20.90
20.61 PPP(mr+rm) PPP (mmrr)
1Β1
6 21.00-21.50 21.40
20.61 PPP(mmmr+rmmm + rmmr) PPP(mmmr+rmmm)
1Β1
7 21.71 20.61 PPP(mmmm) DPD PPD+DPP 1Β1
8 22.88 22.65 DDP+PDD PDP DDD EDE EDD+DDE 2Β8
9 24.30 25.08 DED ββΒ8
10 10a 10b 10c 10d
24.35-24-85 24.40 24..57 24.63 24.80
24.58 PEP PPEPP
EPEPE(m) PPEPE+EPEPP
EPEPE(r)
ββΒ1
11 11a 11b
26.9-27.1 26.97 27.03
27.52 PDP PDD+DDP DDD PDP(mr) PDP(mm)
7Β8
12 27.15 27.52 EDE EDD+DDE DEE+EED
7Β8 βΒ8
13 13a 13b 13c
27.18-27.43 27.18 27.24 27.41
27.27 EEP+PEE PPEE+EEPP(r) PPEE+EEPP(m)
EPEE+EEPE
βΒ1
14 28.16 -28.53 28.38 PPP DPD DPP+PPD brΒ1
EQUATIONS RELATING TRIADES AND 13C NMR SPECTRUM INTEGRALS
Equations for the quantitative Analysis of Ethylene–Propylene–1-Decene Terpolymers
Equation of triads centered in E
Equation of triads centered in P
Equation of triads centered in D
[EEE] = (I16+I17-I22)/2
[EEP+PEE] = I13
[PEP] = I10
[EED+DEE] = I12-I22+I11
[DED] = I9
[EPE] = I23
[EPP+PPE] = I20
[PPP] = I14-I37+I29-I36
[DPP+PPD]+[DPD] = I37-I29+I36
[PDP] = I29-I34-I36
[DDD] = I36
[DDP+PDD] = I34
[EDE] = I33 ou (I25-(I12-I22+I11)/2)/2
[EDD+DDE] = (2*(I26+I27-I9))/5
Triad sequence distribution of the terpolymers obtained by 13C NMR using the 1-decene concentration in the feed of 0.176 M.
ED 30 EPD 14 EPD 13 EPD 17 EPD 19 EPD 21 EPD 28 EPD 24 PD 33
[EEE] 57.9% 69.7% 64.1% 24.0% 5.7% 3.2% 1.2% 0.3% 0.0%
[EEP+PEE] 0.0% 4.5% 9.3% 27.1% 12.4% 9.7% 4.1% 0.0% 0.0%
[PEP] 0.0% 0.3% 1.0% 8.5% 14.6% 16.6% 9.1% 4.1% 0.0%
[EED+DEE] 23.9% 14.2% 12.0% 6.5% 7.0% 1.7% 0.0% 0.0% 0.0%
[DED] 3.8% 0.6% 0.4% 0.9% 0.8% 0.0% 0.0% 0.0% 0.0%
[EPE] 0.0% 2.3% 5.1% 19.3% 17.5% 11.7% 1.5% 1.5% 0.0%
[EPP+PPE] 0.0% 0.0% 1.2% 5.3% 23.6% 24.8% 16.9% 4.9% 0.0%
[PPP] 0.0% 0.0% 0.0% 2.9% 9.8% 27.0% 64.3% 82.3% 92.3%
[DPP+PPD]+[DPD] 0.0% 0.0% 0.0% 0.0% 1.6% 2.6% 2.1% 4.6% 2.8%
[PDP] 0.0% 0.0% 0.0% 0.0% 0.4% 0.9% 0.8% 2.3% 4.9%
[DDD] 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%
[DDP+PDD] 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%
[EDE] 12.3% 7.7% 6.1% 3.6% 4.7% 1.7% 0.0% 0.0% 0.0%
[EDD+DDE] 2.1% 0.7% 0.8% 1.8% 1.9% 0.0% 0.0% 0.0% 0.0%
[E] 85.6% 89.3% 86.8% 67.1% 40.5% 31.3% 14.5% 4.4% 0.0%
[P] 0.0% 2.3% 6.3% 27.6% 52.5% 66.1% 84.8% 93.3% 95.1%
[D] 14.4% 8.4% 6.9% 5.4% 7.0% 2.6% 0.8% 2.3% 4.9%
Comonomer average sequences lengths (nXY) and reactivity ratios (rXY) calculated by 13C NMR
nEP = [EEE]+[EEP+PEE]+[PEP] (EP=)[PEP] + ½ [EEP+PEE] nPE =[PPP]+[EPP+PPE]+[EPE] (PE=)[EPE]+ ½ [EPP+PPE]
nED = [EEE]+[EED+DEE]+[DED] (ED=)[DED]+ ½[EED+DEE] nDE =[DDD]+[EDD+DDE]+[EDE] (DE=)[EDE]+ ½ [EDD+DDE]
nPD =[PPP]+[DPP+PPD]+[DPD] (PD=)[DPD]+½ [DPP+PPD] nDE =[DDD]+[PDD+DDP]+[PDP] (DP=)[PDP] + ½ [DDP+PDD]
rEP = 2 [EE] rED = 2 [EE] rPD = 2 [PP] X1 [EP] X2 [ED] X3 [PD] rPE = 2 X1 [PP] rDE = 2 X2 [DD] rDP = 2 X3 [DD] [PE] [DE] [DP] X1= [E]/[P] in the feed X2= [E]/[D] in the feed X3= [P]/[D] in the feed
[D] = 0.088 M in the liquid phase
nEP nPE rEP rPE rEPrPE nED nDE rED rDE rEDrDE nPD nDP rPD rDP rPDrDP ED26 - - - - - 30.5 1.0 24.3 0.1 2.7 - - - - -
EPD16 32.8 1.0 10.3 0.0 0.0 35.7 1.1 30.2 0.1 3.5 - - - - -
EPD15 13.1 1.1 8.3 0.4 3.2 37.7 1.0 33.8 0.1 2.3 - - - - -
EPD18 2.9 1.2 3.8 0.5 1.8 33.6 1.2 36.0 0.3 11.9 - - - - -
EPD20 1.6 1.8 3.9 0.5 1.9 20.3 1.6 31.2 0.7 22.4 - - - - -
EPD23 1.4 3.3 6.6 0.5 3.3 - - - - - 75.8 1.0 55.4 0.0 0.0
EPD27 1.3 6.5 15.1 0.4 6.0 - - - - - 62.8 1.0 38.2 0.0 0.0
EPD25 1.1 10.8 10.8 0.3 3.7 - - - - - 90.5 1.0 52.4 0.0 0.0
PD32 - - - - - - - - - - 90.4 1.1 33.4 0.7 23.6
ZrCl Cl
rac-EtInd2ZrCl2/MAO
Al/Zr=1500
P=1 atm
SILVA. A. A. da; GALLAND. G. B. Study of propylene-1-butene-ethylene terpolymer and reactor blend by TREF and 13C-NMR. J. Applied Polymer Science. 2001. 80. 1880.
DA SILVA. M.A.. GALLAND. G.B. Synthesis and Characterization of Ethylene-Propylene-1-Pentene Terpolymers. J. Polymer Science:Part A: Polymer Chem.. 2008. 46. 947.
GALLAND. G. B.; ESCHER. F. F. N.. 13Carbon nuclear magnetic resonance of ethylene-propylene-1-hexene terpolymers. J. Polymer Science Part A-Polymer Chemistry. 2004. 42. 2474.
GALLAND. G. B.; SANTOS. J. H. Z. dos; DALL´AGNOL. M.; BISATTO. R.. Study of Ethylene-Propylene-1-Hexene Co- and Terpolymers obtained with homogeneous and supported metallocene catalysts. Macromolecular Symposia. 2006. 245-246. 42. ESCHER. F. F. N.; GALLAND. G. B.; FERREIRA. M.. 13Carbon Nuclear Magnetic Resonance of Ethylene-propylene-1-decene Terpolymers. J. Polymer Science Part A-Polymer Chemistry. 2003. 41. 2531. GALLAND. G. B.; ESCHER. F. F. N.. 13Carbon Nuclear Magnetic Resonance Characterization of ethylene-propylene-1-octadecene terpolymers and comparison with ethylene-propylene-1-hexene and 1-decene terpolymers. Polymer. 2006. 47. 2634.
CHARACTERIZATION OF ETHYLENE-PROPYLENE-α-OLEFIN TERPOLYMERS
BY 13C NMR
Peak Integrals
Type of branch
Amount of branch
BROOKHART CATALYSTS
Galland, G.B.; de Souza, R.F.; Mauler, R.S.; Nunes, F.F. Macromolecules, 1999, 32 1620-1625. Galland, G.B.; Da Silva, L.P.S.; Dias, M.L.; Crossetti, G.L.; Ziglio, C.M,; Filgueiras, C.A.. J. Polym. Sci .: Part A: Polymer Chem., 2004, 42, 2171-2178.
Methyl
Ethyl
Propyl
Butyl
Pentyl
Long
1,4-methyl
1,6-methyl
1,2-ethyl
iso-butyl
2-methyl-hexyl
POLYETHYLENE STRUCTURES OBTAINED WITH DADNi(NCS)2 CATALYST
NN
O
NiBr Br
MAO, toluene
RR = H, CH3, C4H9
poly(α-olefin)
Poly(1-hexene) homopolymers obtained using 1/ΜΑΟ.
13C NMR CHARACTERIZATION OF POLY-α-OLEFINS OBTAINED WITH AN α-KETO-β-DIIMINE NICKEL INITIATOR
1
Azoulay, Jason D., Schneider, Yanika, Galland, Griselda B., Bazan, Guillermo C. Chemical Communications 1996, 6177 - 6179, 2009. Azoulay, Jason D., Rojas, Rene S., Serrano, Abigail V., Ohtaki, Hisashi, Galland, G. B., Wu, Guang, Bazan, Guillermo C. Angewandte Chemie (International Edition), 48, 1089 - 1092, 2009.
Entrya Conditionsb TOFc Mnd PDI Tg
e
1/10 25 °C, 10 mL 1-hexene 356 120 2.0 -56
2/10 0 °C, 10 mL 1-hexene 89 157 1.2 -55
3/12.5f -10 °C, 15 mL 1-hexene 300 120 1.05 -62
[a] µmoL of 1; [b] entries 1-2 carried out in a Schlenk flask in 10 mL toluene at a [1-hexene] = 4 M, In entry 3 [1-hexene] = 0.85 M; [c] hr-1 [d] × 10-3 g mol-1 determined by GPC in o-dichlorobenzene at 135 °C as determined by GPC versus polystyrene standards; Mn values calculated on the basis of TOF are lower than those shown and indicate that the use of polystyrene standards substantially overestimates the Mn for entries 1- 3. [e] oC; [f] In entry 3, the volatiles were removed from a commercially available MAO solution.
13C NMR spectrum of the poly(1-hexene) obtained in entry 1.
Azoulay, Jason D., Bazan, Guillermo C., Galland, Griselda B. Macromolecules, 43,.2794 - 2800, 2010.
Poly(1-hexene) 13C Nuclear Magnetic Resonance results, calculated and observed chemical shifts and assignments.
Peak No
Chem. Shift Calc. (ppm)
Chem. Shift Exp. (ppm)
Assignments Sequences
1 11.36 11.10 1B2 [EBE] 2 13.86 14.15 1B4, 1Bn [EHE]+[HHH]+[HHE+EHH]+[PHH]+[PHE]+[ELE] 3 14.35 14.60 1B3 [EAE] 4 19.63 19.85 1B1 [EPE]
20.21 20.00 2B3 [EAE] 5 20.12 20.30 1B1 [EPH] 6 22.65 22.86 2Bn [ELE] 7 22.90 23.30-
23.45 2B4 [EHE]+[HHH]+[HHE+EHH]+[PHH] ]+[PHE]
8 25.08 24.1-24.4
ββB4 [HEH]
9 27.16 26.51 2B2 [EBE] 10 27.52 26.9-
27.1 βB4 [EEHH+HHEE]
11 27.52 27.17 βB2, βB3, βB4, βBn, (n-1)Bn,
[EEB+BEE]+[EEA+AEE]+[EEH+HEE]+[EEL+LEE]
[E]= [EEE]+[HEH]+[PEE+EEP]+[EEH+HEE]+[EEB+BEE]+[EEA+AEE]+[EEL+LEE]= I16/2+ I8+ I10+I11+I12
[HEH]=I8
[EEH(H)+(H)HEE]= I10 [EEB+BEE]+[EEA+AEE]+[EEH+HEE]+[EEL+LEE] = I11
[EEP+PEE]= I12 [HEEP*]+[PEEP*]=I13/2 [EEE]=I16/2 [EH*H]=I20/2 [P]= [EPE]+[EPH]= I4-I3+I5
[EPE]= I4-I3 [EPH]= I5
[B]=[EBE]=(I1+ I30)/2 [A]=[EAE]=(I3+ I26)/2 [H]= [EHE]+[HHH]+[HHE+EHH]+[PHH]+[PHE]=(I7+I14)/2 or I23-I1-I26+I22-I4+I3+I25 [EHE]=I23-I1-I26 [HHH]+[PHH]=I22-I4+I3 [HHH]= I22-I4+I3-I35
[(H)HHH]= I33
[(E)HHH]= I22-I4+I3- I35-I33
[HHE+EHH]=(E)HHE + (H)HHE= (I25 -I34) [PHH]= I35 [PHE]=I34
[L]= [ELE]=(I6+I21)/2
Equations used in the quantitative analysis of the poly(1-hexene)
Methyl branches
Ethyl branches Propyl branches
Butyl branches
Long branches
13C NMR Spectra of entry 1- 3.
250C
00C
-100C
Sequences
25OC/4M 0OC/4M 10OC/0.85M [E] 48.7% 41.7% 56.5% [HEH] 0.0% 0.0% 8.6% [EEHH+HHEE] 10.9% 14.3% 6.5% [EEB+BEE]+[EEA+AEE]+[EEH+HEE]+[EEL+LEE]+[EEP+PEE] 6.3% 4.8% 15.0% [EEP+PEE] 12.8% 8.1% 10.4% [PEEP*]+[HEEP*] 4.8% 2.7% 0.6% [EEE] 18.6% 14.4% 16.0% [EEP] 7.0% 4.2% 6.4% [EEB]+[EEH]+ [EEA] + [EEL] 15.1% 18.2% 13.9% [EH*H] 1.4% 1.4% 2.0% [P]= [EPE]+[EPH] 11.7% 6.6% 7.1% [EPE] 5.4% 3.3% 4.7% [EPH] 6.2% 3.3% 2.4% [B]=[EBE] 0.3% 0.8% 0.3% [A]=[EAE] 0.7% 0.4% 0.9% [H]= [EHE]+[HHH]+[HHE+EHH]+[PHH]+[PHE] 37.0% 48.6% 33.9% [EHE] 4.4% 4.2% 14.3% [HHH]+[PHH] 14.3% 27.2% 6.0% [HHH]=[(H)HHH+(E)HHH) 10.8% 25.2% 6.0% [(H)HHH] 8.0% 18.0% 2.1% [(E)HHH] 2.8% 7.3% 4.0% [(H)HHE]+EHH 13.5% 12.7% 7.5% [(E)HHE 2.1% 3.2% 4.8% [HHE+EHH]=(E)HHE + (H)HHE+EHH 15.6% 16.0% 12.3% [PHH] 3.5% 2.0% 0.0% [PHE]= 2.7% 1.2% 1.2% [L]= [ELE] 1.7% 2.0% 1.2% [E]+[P]+[B]+[A]+[H]+[L] 100.0% 100.0% 100.0%
Percentage of monomer sequences in mol % of the poly(1-hexene) obtained at different reaction temperatures and concentrations
Butyl branches decrease with the increase of temperature 1,2-insertion becomes less
favored at 25oC
Methyl branches increase with the temperature increase
showing acceleration of 2,6-enchainment and chain working
processes
The significant decrease of the
1,2-insertion of 1-hexene is
attributed to the low concentration
of 1-hexene
LNiP
1 5
4
3
2 61,2-insertionLNi
1 5
4
32
6P
1,2-insertion2,6-enchainment
LNi P
1
5
4
32
62,1-insertion
LNi P
1
5
4
2
6
5'
4'3'
6'
1'
2'
"chain-walking"
1' 2'
3'4'
5'6'
1,2-insertion
LNi P
1
5
4
26
5'
4' 3'
6'
1'2'
3
3LNi
2,6-enchainment
P6'
5'
4'
3'2'
1'
1
5
4
2
6
3
2,6-enchainment
2,1-insertionLNi 5
P
4
2
6
3
1
1,6-enchainmentLNi 15
4
3
26 P
β-hydride elimination
LNi
5
P
4
2
3
1H
6
LNi
154
2P3
LNi
54
2
31H
6
LNi1
54 2
6
3
PLNi
54
2
31H
6
P
1
5
43
2
6
LNiP
1
5
43
2
6
LNiP
Methyl BranchesPHHEPHEEP
Butyl BranchesHHH
HEEP* PEEP* Long BranchesELE
(EEE)n
6
Propyl BranchesEAE
β-hydride elimination
Ethyl BranchesEBE
β-hydride elimination
LNi P
Methyl BranchesEPE
1
54 2
63
(2)(3)
(4) (5)
(6) (7)
(8)
(9)
(10)
(11)
(12)
(13)
(14)
(15)
(16)
(17)
Proposed mechanism of branch formation
T=-20oC T=-60oC
ISOTACTIC PROPYLENE OBTAINED WITH AN α-KETO-β-DIIMINE NICKEL INITIATOR
13C NMR chemical shifts of regioirregular polypropylene Peak Chemical shift
Exp.(ppm) Chemical shift
Calc.(ppm) Sequence Assignment 1 14.57 16.64 PP*P W Pαγ 7 2 15.72 17.13 PP*P*+PPP*(head-to-head) O Pαβ 4 3 19.80-20.10 20.61 PPP(rr) CH3 3a 19.82 20.61 PPPPP(mrrm) CH3 3b 19.92 19.63 EPE F Pδδ 2
19.63 EPP*E+EP*PE Pγδ 8 19.98 19.61 PPPPP(mrrr) CH3
3c 20.08-20.30 19.61 PPPPP(rrrr) CH3 4 20.69 20.61 PPPPP(mrmr) CH3
P*P*PP+ P*P*PP (tail-to-tail) V Pβγ 6 5 20.86 20.61 PPPPP(mmrm+rmrr) CH3
20.12 EPP+PPE E Pβδ 1 6 21.02 20.61 PPPPP (mmrr) CH3 7 21.15-21.50 20.61 PPPPP(rmmr) CH3 8 21.59 20.61 PPPPP(mmmr) CH3 9 21.82 20.61 PPPPP(mmmm) CH3 10 24.58 24.58 PEP S Sββ 5 11 27.16 27.27 EEPP+PPEE L Sβδ 3 12 27.32 27.52 PPEE (r) A Sβγ 1 13 27.54 27.52 PPEE (m) A Sβγ 1 14 27.73 27.52 PEE+EEPE I Sβγ 2 15 28.2-28.9 28.38 PPP CH
28.72 PPPPP(mmmm) CH 16 29.87 29.96 EEE N Sδδ 3 17 30.29 30.21 EEEP+PEEE M Sγδ 3 18 30.77 30.45 EPP+PPE+ C,J, Tβδ 1,3 19 31.01 30.45
31.53 P*P*PP+ P*P*PP (tail-to-tail)
PP*P U Y
Tβδ Sβαβδ
6 7
Quantitative equations Percentages of sequences obtained from equations
Sequence Calculation from integrals [PPP] I15 [EPP+PPE] I18 [EPE] I20 [EEE] I16/2 [EEP+PEE] I11+ I12+ I13+ I14 [PEP] I10 [PP*P*+PPP*] (I23 +I26)/2 [P*PP+P*P*PP] I19-I1 [PP*P] I1 [EP*PE+EP*PE] I21 mmmm I9 mmmr I8 rmmr I7 mmrr I6 mmrm+rmrr I5-I18 mrmr I4- (I19-I1) rrrr I3c mrrr I3b- I21-I20 mrrm I3a
Sequence -20oC -60oC [PPP] 70.90% 100.00% [EPP+PPE] 12.86% 0.00% [EPE] 0.72% 0.00% [EEE] 0.49% 0.00% [EEP+PEE] 9.15% 0.00% [PEP] 1.50% 0.00% [PP*P*+PPP*] 1.25% 0.00% [P*P*PP]+P*P*PP 1.31% 0.00% [PPP*P] 0.85% 0.00% [EP*PE+EP*PE] 0.98% 0.00% [P] 84.48% 100.00% [E] 11.14% 0.00% [P*] 4.38% 0.00% mmmm 62.7% 85.0% mmmr 19.8% 3.6% rmmr 2.5% 0.9% mmrr 5.0% 3.4% mmrm+rmrr 0.0% 2.1% mrmr 1.8% 1.4% rrrr 2.3% 1.3% mrrr 3.2% 1.2% mrrm 2.8% 1.0% mm 84.9% 89.5% mr+rm 6.8% 6.9% rr 8.3% 3.5% m 88.3% 93.0% r 11.7% 7.0%
Statistical models
Pm σ Pmm Pmr Prr Pmmmm
Enantiomorphic Site model
0.964 0.896 0.069 0.035 0.833
Chain End model 0.930 0.865 0.130 0.005 0.748
Experimental 0.93 0.895 0.069 0.035 0.850
Structure 1
Isolated 3,1-enchainment
(1,2)(3,1)(1,2)
Structure 2
Alternating 3,1-enchainment
(1,2)(3,1)(1,2)(3,1) Structure 3
Successive 3,1 enchainment
(1,2)(3,1)(3,1)
Structure 4
Head to head
(1,2)(1,2)(2,1)(2,1) Structure 5
Isolated 3,1-enchainment after inversion (2,1)(3,1)(1,2)
Structure 6
Tail to tail
(2,1)(2,1)(1,2)(1,2) Structure 7
Head to head +tail to tail
(1,2)(2,1)(1,2)
Structure 8
(3,1)(2,1)(1,2)(3,1)
Possible structures of isotactic regio- irregular polypropylene
Sequence -20oC -60oC
0 82,9% 100,0%
1 7,9% 0,0%
2 0,8% 0,0%
3 1,5% 0,0%
4 1,5% 0,0%
5 1,7% 0,0%
6 1,5% 0,0%
7 1,0% 0,0%
8 1,1% 0,0%
ACKNOWLEGMENTS
STUDENTS:
Adilson Arli da Silva Filho Adriane Gomes Simanke Fernanda Nunes Escher Marco Antonio da Silva
ACKNOWLEGMENTS
COLLABORATIONS:
Prof. Dr. Raul Quijada- Universidad de Chile- Chile
Prof. Dr. René Rojas Guerrero- Universidad Católica de Chile- Chile
Prof.a Dra. Maria Lujan Ferreira- Universidad de Bahia Blanca- Argentina
Prof. Dr. Marcelo Villar- Universidad de Bahia Blanca- Argentina
Prof. Dr. Guillermo Bazan- University of California at Santa Barbara- USA
Prof. Dr. Marcos Lopes Dias- Universidade Federal do Rio de Janeiro- Brazil
Prof. Dr. José Carlos Pinto- Universidade Federal do Rio de Janeiro- Brazil
ACKNOWLEGMENTS
ACKNOWLEGMENTS
CNPQ
FAPERGS
Thanks to the following agencies for financial support:
CAPES
THANK YOU FOR YOUR ATENTION!
