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Thermo-mechanical Properties of Urea-based Pattern Molding Compounds for Investment Casting

  • H. Rutto and W. W. Focke
Published/Copyright: April 6, 2013
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International Polymer Processing
From the journal International Polymer Processing Volume 25 Issue 1

Abstract

Urea is a low cost material with thermal and mechanical properties suitable for use in investment casting pattern molding compounds. Conventional compounds are made by a “cooking” process wherein the urea is added to and dissolved in an aqueous solution of a water soluble polymer followed by evaporation of the water. Here we describe novel formulations based on either polyvinyl alcohol (PVOH) plasticized by glycerol or ethylene vinyl acetate (EVA) resins together with wax that can be prepared by a facile twin-screw compounding process. The thermo-mechanical properties of these compounds were characterized using differential scanning calorimetry (DSC), thermo gravimetric analysis (TGA), dynamic mechanical analysis (DMA) and three bend point tests. The PVOH-based molding compounds featured better mechanical properties than those based on EVA. Increasing the polymer content produced weaker but tougher molding compounds. Increasing wax content improved stiffness but resulted in a loss of toughness. The TG results showed that both compounds decomposed readily at elevated temperatures and left less than 3 wt.% ash at 800°C.

∗ Mail address: Walter W. Focke, Institute of Applied Materials, Department of Chemical Engineering, University of Pretoria, Pretoria 0002, Republic of South Africa. E-mail:

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Received: 2009-01-10
Accepted: 2009-09-22
Published Online: 2013-04-06
Published in Print: 2010-03-01

© 2010, Carl Hanser Verlag, Munich

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  2. Contents
  3. Editorial
  4. Professor James Lindsay White 1938–2009
  5. Regular Contributed Articles
  6. Effect of Clay on Thermal, Mechanical and Gas Barrier Properties of Biodegradable Poly(lactic acid)/Poly(butylene succinate) (PLA/PBS) Nanocomposites
  7. Thermo-mechanical Properties of Urea-based Pattern Molding Compounds for Investment Casting
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https://doi.org/10.3139/217.2256

Articles in the same Issue

  1. Contents
  2. Contents
  3. Editorial
  4. Professor James Lindsay White 1938–2009
  5. Regular Contributed Articles
  6. Effect of Clay on Thermal, Mechanical and Gas Barrier Properties of Biodegradable Poly(lactic acid)/Poly(butylene succinate) (PLA/PBS) Nanocomposites
  7. Thermo-mechanical Properties of Urea-based Pattern Molding Compounds for Investment Casting
  8. Erosion Wear Analysis of SiC Filled Glass-Epoxy Composites using Taguchi Technique
  9. Production and Characterization of PP/LDPE Blend Filament Yarns under Industrial Conditions
  10. Modelling Post-molding Warping
  11. Modelling Post-molding Warping
  12. Appropriate Boundary Conditions in the Flow of Molten Polymers
  13. Multiscale Simulation of Injection Molding of Parts with Low Aspect Ratio Microfeatures
  14. PPS-News
  15. PPS News
  16. Seikei Kakou Abstracts
  17. Seikei-Kakou Abstracts
  18. Polímeros: Ciência e Tecnologia Abstracts
  19. Polímeros: Ciência e Tecnologia – Abstracts
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