Faculty: Dr. M. Thompson

Professor
Department of Chemical Engineering

Director, M.Eng in Manufacturing Engineering

McMaster Manufacturing Research Institute (MMRI) Member

McMaster University
1280 Main Street West, Hamilton
Ontario, Canada  L8S 4L7

Office: JHE-A411
email: mthomps@mcmaster.ca
voice: (905) 525-9140 ext.23213

The research interests of my group are primarily focused around extrusion machinery, whether the process of study serves the plastics, pharmaceutical or functional foods industries.  Through experiments and modeling, knowledge and software tools are being produced to assist these industrial sectors in controlling or developing their processes.  We are particularly interested in controlling the morphology of an extruded material system in order to achieve desired product specifications.

Current Areas of Research

• Granulation extrusion – particle design by wet or dry processes for pharmaceutical, nutriceutical, foods and detergent applications.  Tailoring of particle size/shape/porosity on a continuous basis within an extruder through screw design and process layout.  Current work includes studying the mechanisms involved in wet granulation within the extruder when using liquid injection or foam delivery methods.  Additionally, melt granulation is being studied for its capacity to improve the storage and bioavailability of moisture-sensitive or highly hydrophobic APIs, showing this method is often a desirable alternative to hot melt extrusion techniques.
• Spray drying– encapsulating of biologically active ingredients in appropriate diluents for aerosol delivery forms. (new)
• Composite/Bioplastics processing – controlling structural features within an extruder.  Examination of interfacial and colloidal properties for conventional and nano-scale fillers within a polymer matrix of synthetic or biological origins.  Understanding and modeling the relationship of morphology and end-user specification in product design
• Gas-polymer and liquid-polymer dispersive extrusion – customization of polymer products in continuous or discrete forms to exhibit important features as end properties.  This includes preparation of foams but may alternatively use the non-polymer phase to create a beneficial morphology within the polymer.
  
  

  Recent Research Projects

  1. Granulation Extrusion

  Twin screw extrusion (TSE) is a relatively novel technology for the Pharmaceutical and Nutraceutical industries, offering continuous manufacturing capability with superior mixing of particulate matter being granulated or wetted. Our research examines:

• Foam granulation – this robust, continuous manufacturing technology using a twin screw extruder was developed by our group in collaboration with the original co-inventor (Paul Sheskey, Dow Chemical) to consider aqueous foam as a binder. 
• Wet granulation – studying the influence of process, material and screw design factors on granule development, using liquid injection or foam delivery methods.
• Melt granulation – use of a molten binder to granulate excipients without the use of water.
  
  
  

Experimental studies and numerical particle simulation approaches are being used to advance the integration of extrusion technology into these industries.
Select publications of previous work (Front pages):

“Foam Granulation – A new approach to continuous wet granulation using a twin screw extruder”. Pharmaceutical Technology, March 2013.

“Examining the mechanics of granulation with a hot melt binder in a twin-screw extruder”, Chemical Engineering Science, 2012


“Foam granulation: new developments in pharmaceutical solid oral dosage forms using twin screw extrusion machinery”, Drug Development and Industrial Pharmacy, 2012      
       
“Wet Granulation in a Twin-Screw Extruder: Implications of Screw Design”, Journal of Pharmaceutical Sciences, 2010

 

2. Particple Processing Studies of Extrusion Processes



 

 

• Fig. 1: 3mm pellets entering a single-screw extruder

  Fig. 2: Granulation of 0.1mm powder in a kneading element of a co-rotating twin screw extruder

  Particulate processing with screw extruders has been a vital industrial operation for decades. Plastics, food, and pharmaceutical industries rely on extruders to transform solids into more useable forms. Despite the importance of solids-related interactions within this machinery, little attention has been given to the granular mechanics taking place due to the difficulties in modeling such phenomena. Both design and troubleshooting activities on this class of machinery can be vastly improved if we can fully understand the whole process. The research conducted by my group is looking at the mechanisms of solids-conveying, melting, and granulation in extruders, both experimentally and with the use of numerical tools such as the “Distinct Element Method (DEM)”.

  Select Publications: (Front Pages)

  
  

  “Investigation of Solids Transport in a Single-Screw Extruder Using a 3-D Discrete Particle Simulation”, Polymer Engineering and Science, 2004

  
  “Modelling the solids inflow and solids conveying of single-screw extruders using the discrete element method” Powder Technology, 2005

  "Determining the collision properties of semi-crystalline and amorphous thermoplastics for DEM simulations of solids transport in an extruder" Chemical Engineering. Science, 2007

   

  3. Bioplastics, Foams and Reactive Modifications

  We are interested in understanding the root phenomena influencing important industrial problems such as product quality and process stability which arise as special materials are being prepared by extrusion.  Bioplastics are a new category of polymers which present benefits to industries where single-use applications are dominant and low mechanical strength can be tolerated, like the packaging sector. As a new material class, these bioplastics often require very different machinery configurations and processing practices be used compared to petroleum plastics.  In foaming, our group is examining processing aspect of foaming by physical and chemical blowing agents and how foaming may be utilized with composite materials like thermoplastic olefin elastomers, glass-fiber reinforced thermoplastics, and nanocomposites to do more than simply reduce part weight, like control fiber orientation.  In reactive modification of polymers, the polymer processing equipment is used as a solvent-less reactor to change the molecular architecture of a material.  Unique chemistries are employed in this high-temperature, high pressure environment to bring about the desired change in the molecular architecture of the polymer

  
  

  Selected Bioplastics Publications

  
  
  "Biocomposites reinforced with cellulose nanocrystals derived from potato peel waste”, Carbohydrate Polymers, 2012

  
  "In situ kinetic study of solid-state crosslinking of potato starch”, Starch, 2011
  
  “The effect of pea fiber and potato pulp on thermal property, surface tension, and hydrophilicity of extruded starch thermoplastics”, Carbohydrate Polymers, 2011

   

  Select Publications on Foams and Reactive Modification/Degradation:

  
  

  “Supercritical CO2 as an Exfoliating Aid for Nanocomposite Preparation: Comparison of Different Processing Methodologies”, Polymer Engineering and Science, 2012

  “Influence of Supercritical CO2 on the Interactions Between Maleated Polypropylene and Alkyl-Ammonium Organoclay”, Journal of Applied Polymer Science, 2011 

  Multiple Percolation in a Carbon-Filled Polymer Composites via Foaming”, Journal of Applied Polymer Science, 2010

  
  “Reduced fibre breakage in a glass-fibre reinforced thermoplastic through foaming”, Composites Science and Technology, 2005

   

  4.  Polymer Composites

  We are interested in tailoring the properties of polymers to better meet the needs in more specialized applications.  On-going projects in clay-polymer nanocomposites and electrically conductive materials have targeted usage to the automotive and alternative energy industries, attempting to show more economical methods of manufacturing or improved properties based on an understanding of transport phenomena and material properties.
  
  

  “Properties of a Carbon Filled Cyclic Olefin Copolymer”, Journal of Polymer Science: Part B-Polymer Physics., 2007

  “Recyclability of a layered silicate-thermoplastic olefin elastomer nanocomposite”, Polymer Degradation and Stability, 2006

  
  

   

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  Selected Publications and Patents

  J. P. Christiano, M. R. Thompson, "Extruder Screw", Davis-Standard Corporation, US
  Patent No. 6, 179,461 (Jan. 30, 2001).
  
  M. R. Thompson, Twin Screw Extrusion for the Granulation of Pharmaceuticals, Annual Technical Meeting for the Society of Plastics Engineers (ANTEC), Cincinnati, OH. Apr 22-24 (2013)
  
  J-M. Restreop-Florez, A. Bassi, M. Thompson, Effect of Biodiesel Addition on Microbial Population in Diesel Storage Tanks, NACE International Corrosion Conference and Expo, 2013.
  
  M. R. Thompson, S. Weatherley, R. Pukadyil, B. Mu, P. J. Sheskey, Foam Granulation Extrusion: A Novel Method to Continuous Wet Granulation of Powder Drug Formulations, American Institute of Chemical Engineers (AICHE) Annual Conference, Pittsburgh, PA, Oct. 28-Nov. 2 (2012)
  
  P. J. Sheskey, B. Mu, M. R. Thompson, Aspects of Foamed Binder Addition for Foam Granulation in a Twin Screw Extruder, American Association of Pharmaceutical Scientists General Meeting, Chicago IL, Oct 14-18 (2012)
  
  M.R. Thompson, S. Weatherley, R.N Pukadyil, and P.J. Sheskey, Foam Granulation Extrusion: A Novel Method to Continuous Wet Granulation of Powder Drug Formulations, American Association of Pharmaceutical Scientists General Meeting, Washington DC, Oct 23-25 (2011)
  
  M. Mazhary, K.E. Nielsen, F.A. Brandys, M.R. Thompson, Understanding thermally induced wrinkling in decorative film laminated sheets, Annual Technical Meeting for the Society of Plastics Engineers (ANTEC), Boston, MA. May 1-5 (2011)
  
  J. Liu, W.R. Rodgers, T. Cao, M.R. Thompson, Exfoliation aids for preparation of polymer-layered silicate nanocomposites, Annual Technical Meeting for the Society of Plastics Engineers (ANTEC), Boston, MA. May 1-5 (2011)

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