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ABSTRACT This work investigates effects of poly(γ‐butyrolactone) (PγBL) with different initiation and termination chain ends on five types of materials properties, including thermal stability, thermal transitions, thermal recyclability, hydrolytic degradation, and dynamic mechanical behavior. Four different chain‐end‐capped polymers with similar molecular weights, BnO‐[C(=O)(CH2)3O]n‐R, R = C(=O)Me, C(=O)CH=CH2, C(=O)Ph, and SiMe2CMe3, along with a series of uncapped polymers R′O‐[C(=O)(CH2)3O]n‐H (R′ = Bn, Ph2CHCH2) withMnranging from low (4.95 kg mol−1) to high (83.2 kg mol−1), have been synthesized. The termination chain end R showed a large effect on polymer decomposition temperature and hydrolytic degradation, relative to H. Overall, for those properties sensitive to the chain ends, chain‐end capping renders R‐protected linear PγBL behaving much like cyclic PγBL. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem.2018,56, 2271–2279
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Probing the Edges between Stability and Degradation of a Series of ZnSe‐Based Layered Hybrid Semiconductors
Abstract The discovery of layered materials with potentially unique electrical and chemical properties has become a major focus of materials research in the past decade. 2D II–VI layered hybrids (LHs) are a family of ligand‐protected layered materials capable of isolation in few‐layer form and possess emissive and electronic properties of potential relevance to semiconductor device technologies. The authors showed previously that, akin to black phosphorus and transition metal dichalcogenides, 2D II–VI LHs are sensitive to ambient atmospheric conditions. However, the causes for degradation of these ligand‐protected materials remain unclear. Using ZnSe‐based LHs, it is shown herein that the stability of these materials is related to the length and chemistry of the organic ligands coordinated to the LH surfaces. Furthermore, exposure to isotopically enriched H218O and18O2reveals that H2O and O2are both reactants contributing to ZnSe‐LH degradation. An H2O‐initiated degradation pathway is proposed and is supported by density functional theory calculations. The findings contribute to the discovery of protection strategies for layered materials and elucidate a degradation pathway that may also be applicable to other layered materials.
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- PAR ID:
- 10368859
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials Interfaces
- Volume:
- 9
- Issue:
- 20
- ISSN:
- 2196-7350
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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