Pyrolysis characteristics and thermal kinetics of expanded polystyrene (EPS) and styrene-methyl methacrylate (St-MMA) copolymer in LFC process
The pyrolysis behaviors of foam patterns have critical infl uences on fl uid morphology and defect formation in Lost Foam Casting (LFC). The pyrolysis behaviors of expanded polystyrene (EPS) and styrenemethyl methacrylate (St-MMA) foams were compared using synchronous thermal analysis (STA), which...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Foundry Journal Agency
2018-11-01
|
| Series: | China Foundry |
| Subjects: | |
| Online Access: | http://ff.foundryworld.com/uploadfile/2018121146476437.pdf |
| Summary: | The pyrolysis behaviors of foam patterns have critical infl uences on fl uid morphology and defect
formation in Lost Foam Casting (LFC). The pyrolysis behaviors of expanded polystyrene (EPS) and styrenemethyl
methacrylate (St-MMA) foams were compared using synchronous thermal analysis (STA), which was
performed under argon atmosphere at different heating rates (from 10 to 40 K•min-1). The degradation heat was
calculated by integrating DSC curves. Results show that the calculated degradation heat of St-MMA (605.28 J•g-1)
was signifi cantly lower than that of EPS (706.71 J•g-1). Furthermore, the non-isothermal iso-conversional method
was used to determine the pyrolysis apparent activation energies of EPS and St-MMA, and results show that the
activation energy of St-MMA (200.36 kJ•mol-1) was apparently higher than that of EPS (167.92 kJ•mol-1). These
calculated results indicate that the weight loss rate of EPS is greater than St-MMA in the pyrolysis process. In
addition, the apparent activation energies at various pyrolysis stages demonstrate that the pyrolysis reactions of
EPS and St-MMA may involve physical and chemical changes in the decomposition layer of the LFC process. |
|---|---|
| ISSN: | 1672-6421 1672-6421 |