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Rheological Behavior of Polycarbonate Melt Under Squeeze Flow |
WANG Tao1, CAO Wei2, YAN Yue1, LI Lei1 |
1. Beijing Institute of Aeronautical Materials, Beijing 100095, China;
2. Engineering Research Center of Mold & Die, Zhengzhou University, Zhengzhou 450002, China |
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Abstract As the existing rheometers are unable to characterize the stress-strain relation in squeeze process, a parrel plate squeeze flow apparatus with constant contact area mode was designed to characterize the rheological behaviour of the melt by measuring pressure and displacement of upper plate. Based on theoretical analysis and numerical calculation, the power law, PTT and XPP models were employed to find the most suitable constitutive equation for squeezing flow. The results show that squeeze stress of polycarbonate melt increases with growth of strain. When the temperature decreases and squeeze velocity increases, the stress-strain relation manifests three segmental distribution, wherever initial squeeze distance does not influence the stress-strain distribution mode and only has an effect on the squeeze stress. Viscoelastic constitutive model can predict the trend of change of squeeze stress, where predictive value of XPP model is more accurate to the experimental data.
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Received: 27 November 2012
Published: 20 May 2013
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