1
Tiffany Marre 1 ; Axel Bart 1 ; Christophe Boisson 2 ; Ronan Cozic 1 ; Olivier Boyron 2 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: [email protected] or [email protected] 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 T HERMAL DECOMPOSITION OF DIFFERENT LLDPE Mol% of comonomer <1% Low resolution of 1 H NMR spectra: quantification by 13 C NMR Mol% between 1 and 4 % 1 H or 13 C (similar results) Mol% of comonomer >4% Quantification by 1 H NMR α-olefin 1-hexene 1-octene Norbornene Solvent Heptane Heptane Heptane Catalytic system Et(Ind) 2 ZrCl 2 + MAO (Al/Zr = 2000) P = 4 bars T = 80°C Et(Ind) 2 ZrCl 2 + MAO (Al/Zr = 2000) P = 4 bars T = 80°C Et(Ind) 2 ZrCl 2 + 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 Sulfinert TM 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 Sulfinert TM 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 Mode 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 Sample weight (mg) Sample 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+6 380 430 480 530 Cyclopropane,1,2-dimethyl-,cis- Cyclopropane, 1-ethyl-2-methyl-, cis- Hexane 1-Nonene Nonane 1-Decene Decane 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+ Décane Undécène + Undécane TGA curve Mol% hexene = -0.15xT 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 Normalized area between 420 and 520 °C % octene in sample Normalized curves with C 10 peak area for hexane and hexene Storage Mode 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 Sample weight (mg) Sample 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 NMR TREF Main volatile decomposition products: hexene and hexane
