Strength development and diffusion in symmetric and asymmetric pairs of amorphous COCs in the vicinity of Tg : a new modified temperature–pressure dependent model
The strength development and healing of symmetric and asymmetric interfaces of amorphous cyclic olefin copolymers (COC) was studied by assessment of diffusion and lap-shear strength measurement of samples bonded at different temperatures, pressures and healing times. Amorphous COCs comprise copolyme...
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sg-ntu-dr.10356-980712020-03-07T13:22:18Z Strength development and diffusion in symmetric and asymmetric pairs of amorphous COCs in the vicinity of Tg : a new modified temperature–pressure dependent model Wang, Z. Y. Yue, Chee Yoon Roy, S. School of Mechanical and Aerospace Engineering Singapore-MIT Alliance, Manufacturing Systems and Technology Programme The strength development and healing of symmetric and asymmetric interfaces of amorphous cyclic olefin copolymers (COC) was studied by assessment of diffusion and lap-shear strength measurement of samples bonded at different temperatures, pressures and healing times. Amorphous COCs comprise copolymers of norbornene and ethylene whereby COCs with differing norbornene content have different glass transition temperature (Tg) and molecular weight. For similar thermal bonding conditions near Tg, the symmetric pairs have larger bond strength than asymmetric pairs. The activation energy calculated using Arrhenius model was independent of molecular weight and norbornene content. The free volume of COCs increased with norbornene content. In the asymmetric pairs, the adherend consisting of the COC grade with lower Tg and larger free volume dominated the diffusion compared to the other COC adherend. The penetration depth for molecular diffusion calculated using the Flory–Huggins theory was consistent with that estimated using the experimental values of the radius of gyration and bond strength. A new modified model that incorporates the combined effects of pressure, temperature and healing time could be used to predict the bond strength of both symmetric and asymmetric COC joints. Moreover, the new model facilitates determination of more reliable values of the activation energy. 2013-06-24T07:47:06Z 2019-12-06T19:50:16Z 2013-06-24T07:47:06Z 2019-12-06T19:50:16Z 2012 2012 Journal Article Wang, Z. Y., Yue, C. Y., & Roy, S. (2012). Strength development and diffusion in symmetric and asymmetric pairs of amorphous COCs in the vicinity of Tg : a new modified temperature–pressure dependent model. Polymer, 53(9), 1932-1938. 0032-3861 https://hdl.handle.net/10356/98071 http://hdl.handle.net/10220/10546 10.1016/j.polymer.2012.03.007 en Polymer © 2012 Elsevier Ltd. |
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The strength development and healing of symmetric and asymmetric interfaces of amorphous cyclic olefin copolymers (COC) was studied by assessment of diffusion and lap-shear strength measurement of samples bonded at different temperatures, pressures and healing times. Amorphous COCs comprise copolymers of norbornene and ethylene whereby COCs with differing norbornene content have different glass transition temperature (Tg) and molecular weight. For similar thermal bonding conditions near Tg, the symmetric pairs have larger bond strength than asymmetric pairs. The activation energy calculated using Arrhenius model was independent of molecular weight and norbornene content. The free volume of COCs increased with norbornene content. In the asymmetric pairs, the adherend consisting of the COC grade with lower Tg and larger free volume dominated the diffusion compared to the other COC adherend. The penetration depth for molecular diffusion calculated using the Flory–Huggins theory was consistent with that estimated using the experimental values of the radius of gyration and bond strength. A new modified model that incorporates the combined effects of pressure, temperature and healing time could be used to predict the bond strength of both symmetric and asymmetric COC joints. Moreover, the new model facilitates determination of more reliable values of the activation energy. |
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School of Mechanical and Aerospace Engineering |
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School of Mechanical and Aerospace Engineering Wang, Z. Y. Yue, Chee Yoon Roy, S. |
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Wang, Z. Y. Yue, Chee Yoon Roy, S. |
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Wang, Z. Y. Yue, Chee Yoon Roy, S. Strength development and diffusion in symmetric and asymmetric pairs of amorphous COCs in the vicinity of Tg : a new modified temperature–pressure dependent model |
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Wang, Z. Y. |
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Strength development and diffusion in symmetric and asymmetric pairs of amorphous COCs in the vicinity of Tg : a new modified temperature–pressure dependent model |
title_short |
Strength development and diffusion in symmetric and asymmetric pairs of amorphous COCs in the vicinity of Tg : a new modified temperature–pressure dependent model |
title_full |
Strength development and diffusion in symmetric and asymmetric pairs of amorphous COCs in the vicinity of Tg : a new modified temperature–pressure dependent model |
title_fullStr |
Strength development and diffusion in symmetric and asymmetric pairs of amorphous COCs in the vicinity of Tg : a new modified temperature–pressure dependent model |
title_full_unstemmed |
Strength development and diffusion in symmetric and asymmetric pairs of amorphous COCs in the vicinity of Tg : a new modified temperature–pressure dependent model |
title_sort |
strength development and diffusion in symmetric and asymmetric pairs of amorphous cocs in the vicinity of tg : a new modified temperature–pressure dependent model |
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2013 |
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https://hdl.handle.net/10356/98071 http://hdl.handle.net/10220/10546 |
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