Lies De Keer, 1 Paul H.M. Van Steenberge, 1 Marie-Françoise Reyniers, 1 Klaus-Dieter Hungenberg, 2,3 Dagmar R. D hooge, 1,4 Guy B.

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1 10 TH WORLD CONGRESS OF CHEMICAL ENGINEERING, BARCELONA, 01-05/10/2017 THE RELEVANCE OF THE TERMINATION RATE COEFFICIENT MODEL TO ACCURATELY DESCRIBE THE CHAIN LENGTH DISTRIBUTION IN THE INDUSTRIAL PRODUCTION OF EXPANDABLE POLYSTYRENE Lies De Keer, 1 Paul H.M. Van Steenberge, 1 Marie-Françoise Reyniers, 1 Klaus-Dieter Hungenberg, 2,3 Dagmar R. D hooge, 1,4 Guy B. Marin 1 1 Laboratory for Chemical Technology, Ghent University, Belgium 2 Department of Polymer Processing and Engineering, BASF SE Ludwigshaven, Germany 3 Institute for Polymer Material and Process, University of Paderborn, Germany 4 Centre for Textile Science and Engineering, Ghent University, Belgium

2 FREE RADICAL POLYMERIZATION OF VINYLIC MONOMERS 2/15

3 ADDED-VALUE OF KINETIC MODELING Challenge: sustainable and high-tech FRP Recommended strategy: model-based design 3/15

4 OUTLINE The relevance of the termination rate coefficient model to to accurately describe the chain length distribution in the in the industrial production industrial production of expandable of expandable polystyrene polystyrene 1. Expandable polystyrene 2. Model construction 3. Termination rate coefficient model 4. Industrial production of EPS 5. Control over chain length distribution 6. Conclusions De Keer L. et al., AIChE J. 2017, 63 (6), /15

5 EXPANDED POLYSTYRENE Expandable polystyrene (EPS) beads + n-pentane as blowing agent Low density and formability rising demand in applications multiple capacity expansions around the world EPS market growth Status 2015: worldwide annual EPS production > 7.5 million tons Important application: insulation for buildings 1 kg oil for the production of EPS saves 150 kg oil for heating of buildings Koetzing, P. et al., Kunstst.-Plast Eur. 1995, 85 (12), Raps, D. et al., Polymer 2015, 56, /15

6 MODEL CONSTRUCTION (1) Iterative loop experiments and simulations DEDICATED EXPERIMENTS Conversion, average molar mass and molar mass distribution data SIMULATIONS Predici (Galerkin h-p method) Input: mechanism + initial kinetic parameters determine appropriate value for kinetic parameters + investigate influence of diffusional limitations 6/15

7 MODEL CONSTRUCTION (2) A [L mol -1 s -1 ] Reaction Reaction equation E a [J mol -1 ] (*) [s -1 ] Chemical initiation DCP f 0k dis 2R , (*) M k d D Thermal initiation D k dr 2M (*) D + M k thi R 02 + R Literature based, extensive screening Chain initiation R 0x + M k p,ix R1, x = Propagation R i + M k p,0 Ri Combination R i + R j k t,0 P i+j Chain transfer monomer R i + M k trm P i + R Chain transfer dimer R i + D k trd P i + R estimation Parameter Model improvement via accurate Kotoulos C. et al., Macromol Chem Phys. 2003, 204 (10), AkzoNobel determination Functional Chemicals of the chain transfer coefficients Woloszyn J.D. et al., Macromol React Eng. 2013, 7 (7), over large temperature range Buback M. et al., Macromol Chem Phys. 1995, 196 (10), /15

8 TERMINATION RATE COEFFICIENT MODEL (1) Multiscale character k t,app ij = k t,app ii k t,app jj for i < i gel k t,app ii = k t 11 i α S for i < i SL k t,app ii = k t 11 i SL α S +α L i α L for i i SL for i i gel k t,app ii = k t 11 i gel α S +α gel i α gel for i < i SL k t,app ii = k t 11 i SL α S +α L i gel α L +α gel i α gel for i i SL Averagebased Appropriate diffusion model necessary DIFFUSION MODELS k t,app = k t,0 k t,app = k t,0 exp ω p 6.362ω 2 3 p ω p Diffusional limitations k t,app = k t,seg k t,trans k t,seg/trans = k t,0 exp B A 1 V F 1 V F,crA 1 + k t,rd ; k t,rd = 4 3 πα2 σx πα3 j c X (140 C, 0.40 m% DCP) Chain length dependent k t,app ij = k t,app ii k t,app jj Johnston-Hall G. et foral., i < Polym i gel ksci ii t,app Polym = k 11 t Chem. i α S for 2008, i < 46 i SL (10), k Best kinetic description with composite ii t,app = k 11 α t i S +α L SL i α L for i i k t model SL Fu Y. et al., Macromol React Eng. 2007, 1 (4), Woloszyn J.D. et al., Macromol React Eng. 2013, 7 (7), Johnston-Hall G. et al., Polym Sci Polym Chem. 2008, 46 (10), for i i gel k ii t,app = k 11 α t i S +α gel gel i α gel for i < i SL 8/15 k ii t,app = k 11 α t i S +α L α SL i L +α gel gel i α gel for i i SL

9 TERMINATION RATE COEFFICIENT MODEL (2) i = j = x m i = j = x n i, j (140 C, 0.40 m% DCP) k t,app ij = k t,app ii k t,app jj for i < i gel k t,app ii = k t 11 i α S for i < i SL k t,app ii = k t 11 i SL α S +α L i α L for i i SL k t,app R 2 = k ij t R i R j for i i gel k t,app ii = k t 11 i gel α S +α gel i α gel for i < i SL i j k t,app ii = k t 11 i SL α S +α L i gel α L +α gel i α gel for i i SL Explicit consideration of apparent chain length dependencies in composite k t -model is important 9/15

10 TERMINATION RATE COEFFICIENT MODEL (3) EPS production: addition of n-pentane as blowing agent Plasticizing effect Incorporated in the diffusion model Composite k t -model able to describe the effect of n-pentane addition? Verification via experimental data of styrene bulk polymerizations: No n-pentane n-pentane Decrease in polymerization rate Lower mass average molar masses (130 C, 0.50 m% DCP, 5 m% n-pentane) Composite k t -model is able to describe the effect of n-pentane incorporation 10/15

11 INDUSTRIAL PRODUCTION OF EPS Complete range of industrially applied conditions Kinetic model covers complete range of industrially applied conditions: C, 0.40 m% DCP, 0-20 m% n-pentane 11/15

12 CONTROL OVER MOLAR MASS DISTRIBUTION Control over complete molar mass distribution (MMD) T=120 C T=130 C T=140 C T=150 C Control over product quality (multimodality) (0.40 m% DCP, no n-pentane) no suppression of gel-effect T n-pentane shorter plasticizing macroradicals effect suppression of gel-effect 12/15

13 CONCLUSIONS An advanced kinetic model is successfully developed and applied for the design of the industrial production of EPS, covering the complete range of industrial production conditions. A fundamental description of the complex interplay between chemistry and transport phenomena is required. Developed model will be applied by industrial partner for further design of the production process at industrial scale. 13/15

14 ACKNOWLEDGMENTS Fund for Scientific Research Flanders (FWO; 1S37517N) Long Term Structural Methusalem Funding by the Flemish Government Interuniversity Attraction Poles Program Belgian State Belgian Science Policy (BELSPO) Department of Polymer Processing and Engineering, BASF SE, Germany 14/15

15 LABORATORY FOR CHEMICAL TECHNOLOGY Technologiepark 914, 9052 Ghent, Belgium E info.lct@ugent.be T