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41 results on '"Miao, Xiaran"'

39. In situ small angle X-ray scattering study on structural evolution of crosslinked polytetrafluoroethylene during deformation.

Author

Li, Xiaoyun, Tian, Feng, Yang, Chunming, Tang, Zhongfeng, Miao, Xiaran, Wu, Guozhong, Li, Xiuhong, Wang, Jie, and Li, Liangbin

Subjects
CROSSLINKING (Polymerization), X-ray scattering, MOLECULAR structure, POLYTEF, DEFORMATIONS (Mechanics), TENSILE strength
Abstract

ABSTRACT The structural evolution of virgin and crosslinked polytetrafluoroethylene (PTFE) during stretching was studied by in situ synchrotron small-angle X-ray scattering (SAXS). Both yield and tensile stress of crosslinked PTFE increased with increasing crosslinking density. During stretching, for virgin PTFE, amorphous chains gradually turned to tensile direction at early stage, perpendicularly arranged lamellar stacks appeared at high strains (>140%). While for crosslinked PTFE, lamellar structure was observed even at lower strains; with increasing irradiation dose, the lamellar structure became obvious and the long period decreased. Four-point SAXS patterns were observed only in 3000kGy-dosed PTFE during deformation, which indicated that an alternately tilted lamella arrangement called herringbone structure was formed. Radiation dose induces crosslinked networks formed, which can carry part of local stress during deformation, resulting in the increase of yield and tensile stress. Crosslinking density is an important factor on structural evolution. In addition, a deformation mechanism of different crosslinked PTFE is proposed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39883. [ABSTRACT FROM AUTHOR]

Published
2014
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40. Effect of Length of Cellulose Nanofibers on Mechanical Reinforcement of Polyvinyl Alcohol.

Author

Wang, Mengxia, Miao, Xiaran, Li, Hui, and Chen, Chunhai

Subjects
*POLYMERIC nanocomposites, *POLYVINYL alcohol, *VAN der Waals forces, *CELLULOSE, *CELLULOSE fibers, *NANOFIBERS
Abstract

Cellulose nanofibers (CNF), representing the nano-structured cellulose, have attained an extensive research attention due to their sustainability, biodegradability, nanoscale dimensions, large surface area, unique optical and mechanical performance, etc. Different lengths of CNF can lead to different extents of entanglements or network-like structures through van der Waals forces. In this study, a series of polyvinyl alcohol (PVA) composite films, reinforced with CNF of different lengths, were fabricated via conventional solvent casting technique. CNF were extracted from jute fibers by tuning the dosage of sodium hypochlorite during the TEMPO-mediated oxidation. The mechanical properties and thermal behavior were observed to be significantly improved, while the optical transparency decreased slightly (Tr. > 75%). Interestingly, the PVA/CNF20 nanocomposite films exhibited higher tensile strength of 34.22 MPa at 2 wt% filler loading than the PVA/CNF10 (32.55 MPa) while displayed higher elastic modulus of 482.75 MPa than the PVA/CNF20 films (405.80 MPa). Overall, the findings reported in this study provide a novel, simple and inexpensive approach for preparing the high-performance polymer nanocomposites with tunable mechanical properties, reinforced with an abundant and renewable material. [ABSTRACT FROM AUTHOR]

Published
2022
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41. Shape-Controllable and Fluorescent Supramolecular Organic Frameworks Through Aqueous Host-Guest Complexation.

Author

Li Y, Dong Y, Miao X, Ren Y, Zhang B, Wang P, Yu Y, Li B, Isaacs L, and Cao L

Abstract

Two kinds of shape-controllable and fluorescent supramolecular organic frameworks (cuboid or spheroid) are constructed hierarchically from CB[8] and tetraphenylethylene derivatives through host-guest interaction in water. These two fluorescent SOFs exhibit intriguing and varied photophysical properties, including large red-shifts (up to 82 nm) and stimuli-responsive behavior to competitive guest by binding with CB[8], the turn-on fluorescence of which is applied in cellular imaging., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Published
2018
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