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46 results on '"Ju, Guannan"'

12. Research on Properties of PBAT/CaCO 3 Composite Films Modified with Titanate Coupling Agent.

Author

Liu, Zhekun, Meng, Fantao, Tang, Xianggang, Su, Chengzhuang, Mu, Qinglin, and Ju, Guannan

Subjects
WATER vapor, CONTACT angle, HETEROGENOUS nucleation, BIODEGRADABLE materials, TENSILE tests
Abstract

High cost, low crystallinity, and low-melt strength limit the market application of the biodegradable material poly (butylene adipate-co-terephthalate) (PBAT), which has become a major obstacle to the promotion of PBAT products. Herein, with PBAT as resin matrix and calcium carbonate (CaCO3) as filler, PBAT/CaCO3 composite films were designed and prepared with a twin-screw extruder and single-screw extrusion blow-molding machine designed, and the effects of particle size (1250 mesh, 2000 mesh), particle content (0–36%) and titanate coupling agent (TC) surface modification of CaCO3 on the properties of PBAT/CaCO3 composite film were investigated. The results showed that the size and content of CaCO3 particles had a significant effect on the tensile properties of the composites. The addition of unmodified CaCO3 decreased the tensile properties of the composites by more than 30%. TC-modified CaCO3 improved the overall performance of PBAT/CaCO3 composite films. The thermal analysis showed that the addition of titanate coupling agent 201 (TC-2) increased the decomposition temperature of CaCO3 from 533.9 °C to 566.1 °C, thereby enhancing the thermal stability of the material. Due to the heterogeneous nucleation of CaCO3, the addition of modified CaCO3 raised the crystallization temperature of the film from 97.51 °C to 99.67 °C and increased the degree of crystallization from 7.09% to 14.83%. The tensile property test results showed that the film reached the maximum tensile strength of 20.55 MPa with the addition of TC-2 at 1%. The results of contact angle, water absorption, and water vapor transmission performance tests showed that TC-2 modified CaCO3 increased the water contact angle of the composite film from 85.7° to 94.6° and decreased the water absorption from 13% to 1%. When the additional amount of TC-2 was 1%, the water vapor transmission rate of the composites was reduced by 27.99%, and the water vapor permeability coefficient was reduced by 43.19%. [ABSTRACT FROM AUTHOR]

Published
2023
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26. Hydrogen Bonding-Induced Alleviation of Topological Constraints in Acrylic Polymers Mixed with Small Molecules

Author

Liu, Yuanbiao, Guo, Kai, Jiao, Enxiang, Xu, Shanshan, Ju, Guannan, Shi, Gaopeng, He, Haochang, Wu, Guozhang, and Zhang, Haijun

Abstract

Intermolecular hydrogen bonds (inter-HBs) typically act as transient cross-linkers and can enhance the intermolecular interactions. Herein, we report a counterintuitive scenario that interchain constraints of polyacrylates are alleviated by adding hindered phenols capable of forming strong inter-HB interactions with the host polymer, even if a small molecule-bridged inter-HB network apparently increases the glass transition temperature (Tg) of the hybrids. The less-constrained segmental dynamics is confirmed enthalpically by the enhanced dynamic homogeneity (i.e., an increase in nonlinearity parameter xand stretching exponential parameter β) of α-relaxation together with a remarkable increase in the physical aging rate at (Tg– 10) K. Further results clarified that xand β values are primarily governed by the strength of inter-HB interactions (Δυi), and a stronger Δυiresults in a larger xor β value. The present work provides solid experimental evidence and new molecular-level insights for the less-constrained segmental dynamics in such HB-driven hybrids in terms of the balanced flexibility between side groups and the backbone, the reduction of energy barriers hindering the cooperative motions, and the alleviation of long-chain connectivity.

Published
2024
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32. Removal of Oil Spills through a Self‐Propelled Smart Device.

Author

Ju, Guannan, Yang, Xiao, Li, Lin, Cheng, Mengjiao, and Shi, Feng

Subjects
*WATER, *HYDROGEN peroxide, *OIL spills, *HYDROPHOBIC interactions
Abstract

Oil/water separation through superhydrophobic/superoleophilic materials has attracted considerable interest over the past decades; however, dealing with oil spills on broad waters through an active way remains a challenge. Herein, we report a self‐propelled smart device driven by the decomposition of hydrogen peroxide that can spontaneously move on the water surface and collect floating oil droplets inside with superhydrophobic and superoleophilic properties. Moreover, the self‐propelled smart device exhibits excellent stability and high efficiency for oil/water separation. We believe this study may provide a promising strategy for fabricating smart aquatic devices that have potential applications in water remediation. [ABSTRACT FROM AUTHOR]

Published
2019
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46. One-Step Fabrication of a Functionally Integrated Device Based on Polydimethylsiloxane-Coated SiO 2 NPs for Efficient and Continuous Oil Absorption.

Author

Ju, Guannan, Zhou, Lei, Jiao, Chang, Shen, Jiafeng, Luan, Yihao, and Zhao, Xinyu

Subjects
*POLYDIMETHYLSILOXANE, *SUPERHYDROPHOBIC surfaces, *SURFACE energy, *SURFACE structure, *SURFACE coatings, *SURFACE roughness
Abstract

The construction of superhydrophobic surfaces necessitates the rational design of topographic surface structure and the reduction of surface energy. To date, the reported strategies are usually complex with multi-steps and costly. Thus, the simultaneous achievement of the two indispensable factors is highly desired, yet rather challenging. Herein, we develop a novel structure engineering strategy of realizing the fabrication of a functionally integrated device (FID) with a superhydrophobic surface via a one-step spraying method. Specifically, silica nanoparticles are used to control the surface roughness of the device, while polydimethylsiloxane is employed as the hydrophobic coating. Benefitting from the adopted superhydrophobicity, the as-fabricated FID exhibits a continuous, excellent oil-water separating performance (e.g., 92.5% separating efficiency) when coupled with a peristaltic pump. Notably, a smart design of incorporating a gas switch is adopted in this device, thereby effectively preventing water from entering the FID, realizing thorough oil collection, and avoiding secondary pollution. This work opens up an avenue for the design and development of the FID, accessible for rapid preparation and large-scale practical application. [ABSTRACT FROM AUTHOR]

Published
2021
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