1. Introduction to Reactive Extrusion
Andrew Hollcraft

2. Traditional Batch Polymerization
• Continuous stirred tank reactor
• Loop reactor
• Solvent based [1]
• Recovery (5-20 times the polymer weight)
• Large and expensive

3. Reactive Extrusion
• Usually co-rotating twin screw [2]
• Polymer production [1]
• Condensation
• Ionic
• Radical
• Emulsion
• Polymer modification
• Grafting and crosslinking
• Chain extension and branching
• Depolymerization – MW fine control
• Vulcanization
• Viscosity management and multi staging [1, 2, 3]
• Stepwise additions
• Venting byproducts
• Specialty polymers
• All kinds of other chemistry

4. Grafting
• Copolymer and additive stability [1]
• Plasticizers– no migration
• Polyolefins – low surface energy
• Polar side group
• Improved blend physical properties
• Wider range of alloys available with polyamides,
polyesters, polystyrene…
• Typically
• Peroxide initiator (masterbatched)
• Maleic anhydride crosslinker
• Polybutylene succinate [4]
• Biodegradable polyester thermoplastic
• Comparable to polypropylene
• Improved nanocomposite performance

5. • Polymerization modeling [5]
• Initiation
• Propagation
• Termination
• Combination
• Disproportionation
• Assumptions
• Auto acceleration – runaway
• Side reactions
• Viscosity
Modeling - Kinetics

6. Rheology Control
• Elasticity of polypropylene [1]
• Slow elastic recovery
• Elastic strain frozen during high throughput manufacturing
• Due to high MWD tail
• Reduced processability (1965)
• Tertiary carbon
• Chain scission readily occurs
• Series of patents in the 70’s
• Result: Narrow MWD
• Ease of processing

7. Reactive Extrusion
Pros
• Specialty polymers and blends
• Multistaging
• Simple design [2]
• Safety - low volume [6]
• Short residence time
• No solvent
• Environmentally friendly
• Less capital investment and overhead
• Reduction in produced resin cost (~10%) [1, 7]
Cons [1,6]
• Cannot handle
• Long reaction times
• High heat evolution
• Residence time and distribution are key
• Chemistry challenges
• Larger educational barrier to entry

8. References
1. Xanthos, Marino. Reactive Extrusion: Principles and Practice. Munich: Hanser, 1992. Print.
2. "REACTIVE EXTRUSION." Clextral. Web. <http://www.clextral.com/technologies-and-
lines/technologies-et-procedes/reactive-extrusion/>.
3. "Reactive Processing." Fraunhofer. Web.
<http://www.ict.fraunhofer.de/en/comp/pe/ce/reactive_processing.html#tabpanel-2>.
4. Phua, Y. J. "Reactive Processing of Maleic Anhydride-grafted Poly(butylene Succinate) and the
Compatibilizing Effect on Poly(butylene Succinate) Nanocomposites." Expresspolymlett Express
Polymer Letters 7.4 (2013): 340-54. Web.
5. "POLYMERIZATION KINETICS." Penn State Polymer Physics Group. Web.
<http://www.plmsc.psu.edu/~manias/MatSE443/chapter3.pdf>.
6. Brown, M. W. R. Reactive Processing of Polymers. Shawbury, Shrewsbury, Shropshire: Rapra
Technology, 1994. Print.Cheremisinoff, Nicholas P. Advanced Polymer Processing Operations.
Westwood, NJ, U.S.A.: Noyes Publications, 1998. Print.
7. "Reactive Extrusion." Coperion. Web. <http://www.coperion.com/en/compounding-
extrusion/applications-products/reactive-extrusion/>.