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Your search keyword '"Liu, Ying Ling"' showing total 314 results
Start Over Author "Liu, Ying Ling" Publication Type Academic Journals
314 results on '"Liu, Ying Ling"'

8. Is a Vitrimer with a High Glass Transition Temperature Available? A Case Study on Rigid Polyimides Cross‐Linked with Dynamic Ester Bonds.

Author

Wang, Yueh‐Hsin, Hung, Du‐Yuan, and Liu, Ying‐Ling

Subjects
TRANSITION temperature, THERMAL properties, DIFFUSION control, HIGH temperatures, WASTE recycling
Abstract

Vitrimers, possessing associative covalent adaptable networks, are cross‐linked polymers exhibiting malleable (glass‐like) feature and recyclable and reprocessable (thermoplastics‐like) properties. The dynamic behaviors of vitrimer are dependent on both chain/molecular mobility (glass transition temperature, Tg) and dynamic bond‐exchanging reaction rate (topology freezing transition temperature, Tv). This work aims on probing the effect of high Tg on the stress relaxation and physical recyclability of vitrimers, employing a polyimide cross‐linked with dynamic ester bonds (Tg: 310 °C) as the example. Due to its high Tg and chain rigidity, the cross‐linked polyimide does not exhibit a high extent of stress relaxation behavior at 320 °C (10 °C above its Tg), even though the temperature is much higher than the hypothetical Tv. While raising the processing temperature to 345 °C, the cross‐linked polyimide exhibits a stress relaxation time of about 3300 s and physical malleability. Nevertheless, side reactions may occur in the recycling and reprocessing process under the harsh condition (high temperature and high pressure) to alter the thermal properties of the recycled sample. The diffusion control plays a critical role on the topography transition of a vitrimer having a high Tg. The Tg ceiling is noticeable for developments of vitrimers. [ABSTRACT FROM AUTHOR]

Published
2024
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39. Reaction between 1,3,5‐Triisopropylbenzene and Elemental Sulfur Extending the Scope of Reagents in Inverse Vulcanization.

Author

Lai, Yue‐Sheng and Liu, Ying‐Ling

Subjects
*SELF-healing materials, *VULCANIZATION, *SULFUR, *RING-opening reactions, *RADICALS (Chemistry), *ORGANIC compounds, *ADENOSYLMETHIONINE
Abstract

Inverse vulcanization utilizes an organic compound as reagent for crosslinking elemental sulfur to result in corresponding polymeric material with a high sulfur content. This work, employing 1,3,5‐triisopropylbenzene (TIPB) as the reagent, demonstrates the first attempt on extending the scope of crosslinking agents of inverse vulcanization to saturate compounds. Under nuclear magnetic spectroscopic analysis, the reactions between TIPB and elemental sulfur take places through ring‐opening reaction of S8 resulting in sulfur radicals at sulfur chain ends, radicals transferring to isopropyl groups of TIPB, and radical coupling reactions between carbon radicals and sulfur radicals. The obtained products are similar to the sulfur polymers from conventional inverse vulcanization processes and show self‐healing property. [ABSTRACT FROM AUTHOR]

Published
2023
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