Post on 17-Feb-2019
Tiffany Marre1 ; Axel Bart1 ; Christophe Boisson2 ; Ronan Cozic1 ; Olivier Boyron2
1 SRA Instruments, 210 rue des Sources, 69280 Marcy l'Etoile, France 2 Université de Lyon, Univ. Lyon 1, CPE Lyon, CNRS UMR 5265, Laboratoire de Chimie Catalyse Polymères et Procédés (C2P2), Equipe LCPP, Bat 308F, 43 Bd du 11 Novembre 1918, F-69616 Villeurbanne, France
* E-mail addresses: r.cozic@sra-instruments.com or olivier.boyron@univ-lyon1.fr
TGA/IST16/GC-MS COUPLING FOR STUDY OF α-OLEFIN CONTENT IN POLYETHYLENE
INTRODUCTION
CONCLUSION The innovative TGA/IST16/GC/MS coupling is a powerful and versatile tool for interpretation of LLDPE structure. For an homopolymer the main volatil decomposition products are decane/decene and undecane/undecene. For an ethylene/hexene copolymer the main decomposition products are butane and butene. For an ethylene/octene copolymer the main decomposition products are hexane and hexene. TGA/IST16/GC/MS coupling is shown to be a viable technique to obtain qualitative and quantitative information on α-olefin content in LLDPE. The quantity of the degradation product is directly proportional to the inserted co-monomer content.
REFERENCES
ACKNOWLEDGEMENTS
Gas : Nitrogen (30 mL/min.) - Analysis rate: 40 to 600 °C at 10°C.min-1
POLYMERIZATION CONDITIONS OF STANDARDS
THERMAL DECOMPOSITION OF DIFFERENT LLDPE
Mol% of comonomer <1% Low resolution of 1H NMR spectra: quantification by 13C NMR Mol% between 1 and 4 % 1H or 13C (similar results) Mol% of comonomer >4% Quantification by 1H NMR
α-olefin 1-hexene 1-octene Norbornene
Solvent Heptane Heptane Heptane
Catalytic system
Et(Ind)2ZrCl2 + MAO (Al/Zr = 2000)
P = 4 bars T = 80°C
Et(Ind)2ZrCl2 + MAO (Al/Zr = 2000)
P = 4 bars T = 80°C
Et(Ind)2ZrCl2 + MAO (Al/Zr = 1000)
P = 3 bars T = 70°C
All polymerization experiments were performed in a 0.5 L glass reactor equipped with an injection chamber for the precatalyst [1].
Polyethylenes (LDPE, LLDPE, HDPE) are the most widely made synthetic polymers in volume with a production of around 75 MT a year. Their physical properties depend tremendously on their structure, so it is important to have rapid method to characterize chain composition. The average composition of the copolymers was measured using 1H, 13C NMR and TREF. Copolymer composition was then investigated by coupling of the TGA with the GC-MS technique to get rapid information about their structure. An innovative TGA/IST16/GC/MS coupling is presented that significantly increase the number of data collected and thus provides an efficient way to take advantage of the GC/MS technique. The configuration uses a fractions collector inserted between the TGA and the GC. With materials such as LLDPE, the majority of the gaseous components leaving a TGA cannot be identified precisely with MS or IR. In this case, coupling of the TGA with the GC-MS technique offers interesting advantages. The emitted compounds are first separated by gas chromatography (GC) then identified and quantified by MS.
Solvent: 1,2,4-Trichlorobenzene Crystallization rate: 0.2°C.min-1
Elution rate: 1°C.min-1
Mettler TOLEDO FRANCE for support in TGA NMR Polymer Service in Lyon for support in NMR
[1] E Cossoul, L Baverel, E Martigny, T Macko, C Boisson, O Boyron , Macromolecular Symposia, 330,42-52 (2013) [2] J.M. Letoffe et al., Journal of Thermal Analysis and Calorimetry. 76, 491-505 (2004) [3].H. Bockhorn, A. Hornung, U. Hornung, D. Schawaller, J. Anal. Appl. Pyrolysis. 48, 93, (1999). [4] M. Mucha, J. Polym. Sci. Symp. 57, 25, (1976). [5] .K. Murata Y. Hirano, Y. Sakata, M. Azhar Uddin, J. Anal. Appl. Pyrolysis 65, 71, (2002).
Solvent: TCB/toluene-d8 (3/1) T = 100°C
QUANTIFICATION OF COMONOMER CONTENT
INSTRUMENTATION IST16 • Number of loop: 16 in SulfinertTM stainless steel [2]
• Loop volume: 250μL in standard, customized volume on demand
• 2 heated zones
• Heated transfer lines: low internal diameter x 1.15 meter in SulfinertTM stainless steel
• Valve box temperature: 250°C as standard working temperature (300°C can be reached for some special applications)
carrier gas sample vent
isolation valve
storage valve
carrier gas sample vent
inject valve
Injection to GC M
ode
Alkenes Profile for homo PE Alkanes profile for homo PE P(E/Octene) 0.4 mol% 1.7 mol% 5.7 mol%
0
5
10
15
20
25
30
0.0E+0
2.0E+6
4.0E+6
6.0E+6
8.0E+6
1.0E+7
1.2E+7
380 430 480 530
Sam
ple
wei
ght (
mg)
Sam
ple
area
Sample temperature (°C) 1-Hexene Hexane 1-Decene Decane
1-Undecene Undecane TGA curve
0
5
10
15
20
25
30
0.0E+0
5.0E+6
1.0E+7
1.5E+7
2.0E+7
2.5E+7
380 430 480 530
0
5
10
15
20
25
30
0.0E+0
2.0E+6
4.0E+6
6.0E+6
8.0E+6
1.0E+7
1.2E+7
1.4E+7
1.6E+7
1.8E+7
380 430 480 530
0
5
10
15
20
25
30
0E+0
1E+6
2E+6
3E+6
4E+6
5E+6
6E+6
7E+6
380 430 480 530Cyclopropane,1,2-dimethyl-,cis- Cyclopropane, 1-ethyl-2-methyl-, cis-Hexane 1-NoneneNonane 1-DeceneDecane TGA curve
0
5
10
15
20
25
30
0.0E+0
2.0E+6
4.0E+6
6.0E+6
8.0E+6
1.0E+7
1.2E+7
1.4E+7
380 430 480 530
Butane + Butène 1-Décène+ DécaneUndécène + Undécane TGA curve
Mol
%he
xene
= -0
.15x
T e+15
.6
Gas: Helium (30 mL/min.) - Analysis rate: 40 to 600 °C at 10°C.min-1
P(E/Hexene) P(E/Norbornene) TIC for P(E/Octene) 0.4mol% and 5.7 mol% (Loop n°8) Calibration Curves of P(E/Octene)
Hexane and hexene signals increase with the quantity of octene in the sample
Decene/decane and undecene/undecane are the main volatile decomposition products
0
10
20
30
40
50
60
0 1 2 3 4 5 6
Nor
mal
ized
area
bet
wee
n 42
0 an
d 52
0 °C
% octene in sample
AlcenesAlcanes
Normalized curves with C10 peak area for hexane and hexene
Stor
age
Mod
e
0
5
10
15
20
25
0E+0
1E+7
2E+7
3E+7
4E+7
5E+7
6E+7
7E+7
380 430 480 530
Sam
ple
wei
ght (
mg)
Sam
ple
area
Sample temperature (°C) 1-Hexene 1-Octene 1-Nonene 1-Decene
1-Undecene 1-Dodecene TGA curve
0
5
10
15
20
25
0E+0
5E+6
1E+7
2E+7
2E+7
3E+7
3E+7
4E+7
380 430 480 530
Hexane Octane Nonane Decane
Undecane Dodecane TGA curve
Gas : Nitrogen (30 mL/min.) - Analysis rate: 40 to 600 °C at 10°C.min-1
Hexene Hexane
NM
R
TREF
Main volatile decomposition products: hexene and hexane