INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2020
·
IF 5.162
Jia Li,Yuankun Wang,Zhifeng Wang,Jun Wang,Defeng Wu
Chitin nanocrystal (ChNC) is good nucleation agent for aliphatic polyesters because of its high-energy surface. To moderate its nucleation activity, silane coupling agents with different chain lengths or functional groups were used to modify ChNCs in this work, and biodegradable poly( β -hydroxybutyrate) (PHB) was used as target polymer for crystallization study. Surface coupling of ChNCs improves their phase adhesion to PHB chain and weakens their nucleation activities. The alterations strongly depend on the surface chain structure of ChNCs: sulfhydryl silane-coupled ChNC shows lowered nucleation activity, whereas amino silane-coupled ChNCs even become antinucleation agents. The interfacial compatibility is vital to altered role of ChNCs and to following changes in spherulite growth and ring-banded morphology, which is further disclosed using Flory-Huggins interaction parameters and rheological responses as probes. This work provides useful information on tailoring the functions of ChNCs as nanoadditive for biodegradable aliphatic polyesters by the way of surface chain engineering.
研究领域:
材料科学
·
生物医学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2023
·Vol. 148
·期 6
·2401-2415
·
IF 4.4
Gao Wei,Li Yufeng,Zhao Jitao,Tang Weiwei,Zhang Zhe,Wang Jun,Wu Zhenyu,Li Minggang
The low crystallization rate and long molding time of poly(ethylene terephthalate) (PET) restricts its application in the field of engineering plastics. PET/graphene oxide (GO) composites were synthesized through in situ polymerization method with dimethyl terephthalate (DMT), ethylene glycol (EG) as reactants and GO as filler in order to overcome the above shortcomings. Influence of GO on the crystallization performance of PET was investigated. It was revealed GO raised the crystallization temperature and crystallization rate of PET, demonstrating the excellent nucleation capability of GO. The mechanism of PET nucleation induced by GO was investigated by Avrami equation and Hoffman-Lauritzen theory. It was obvious the crystallization behavior of PET was improved by reducing the free energy of nucleation and the fold surface free energy of PET caused by GO. Moreover, the non-isothermal kinetics of thermal decomposition of PET and PET/GO composites were studied by Friedman method. It was obvious that all of PET and PET/GO composites exhibited a fine thermal stability with no significant mass loss observed up to 370 °C (< 0.5%). The addition of GO improved the thermal stability of PET through raising the apparent activation energy, inhibiting the escape of volatile products and absorbing the degradation products in PET thermal decomposition procedure.
研究领域:
材料科学
·
高分子化学
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产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2020
·Vol. 138
·期 10
·49966
·
IF 2.52
Yue Yin,Bo Jiang,Linghui Meng
In order to solve the poor nucleation ability and slow crystallization rate of polyethylene terephthalate (PET), we propose a new strategy to prepare PET with self-nucleation ability based on the mechanism of mutual attraction of ions. In this study, a hydroxyl-terminated sulfonate monomer, sulfonated 1,4-butanediol (SBDO) without rigid structure was synthesized as nucleating agent functionalized PET third monomer, and then PET ionomers (PETi) were prepared through melt polycondensation with different contents of SBDO. The half-crystallization time of PETi was sharply decreased in contrast with pure PET and the crystallization temperature was significantly increased from 182.6°C to 210.8°C for PETi1. Due to the high nucleation efficiency of SBDO, the crystallization temperature of PET was significantly increased, avoiding the excessive addition of traditional nucleating agents to deteriorate the mechanical properties of PET. The increased nucleation efficiency was contributed to the aggregation of SBDO induced by the ionic interactions.
研究领域:
高分子化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Crystals
·
2022
·Vol. 12
·期 2
·202
·
IF 2.67
Yanfei Wang,Xiaoyu Chuai,Yifei Li,Jia Guo,Jing Yang,Zhixue Liu,Shijie Xu
In this contribution, we experimentally determined the metastable zone width (MSZW) of adipic acid (AA) in different polar solvents to reveal the nucleation behavior. We performed analyses for different cooling rates, saturation temperatures and polar solvents. The findings showed that the MSZW increased as the cooling rate increased, or saturation temperature or polarity decreased. Here, we suggest that the hydrogen bond donor capacity decreases as the polarity of the solvent decreases, which weakens the solute and solvent interaction and makes the desolvation process more difficult during nucleation. Furthermore, we found that the MSZW is mainly determined by the cooling rate, when the cooling rate is large enough. On account of the classical nucleation theory, it was found that the sizes of the critical nucleus and Gibbs nucleation energy do not increase monotonously with increasing driving force. Moreover, this study confirms that solid–liquid interface tension is associated with crystallization driving force.Keywords:adipic acid;nucleation;MSZW;critical nucleation parameter
研究领域:
化学工程
·
材料科学
·
物理化学
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产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2023
·
IF 7.2
Zongxu Wang,Zixin Li,Amado Velázquez-Palenzuela,Yinge Bai,Haifeng Dong,Lu Bai,Xiangping Zhang
Bubbles generated on the electrode surface have been considered one of important factors limiting the efficiency of hydrogen evolution reaction (HER). However, the bubble formation behaviors have not been clearly defined, especially nanobubbles in ionic liquid system. In this work, single H 2 nanobubbles generation characters are well investigated using platinum nanoelectrodes in ionic liquid (IL) during HER. The crucial factors ( i . e ., critical condition, geometry, and nucleation rapid of the H 2 nanobubbles) are quantitatively conducted from the voltammograms. The results reveal that the H 2 nanobubbles have a small contact angle (from 152° to 160°) and large bubble height (0.5–1.1 nm), which are favorable for subsequent detachment from nanoelectrode surface. Moreover, higher nucleation energy (7.5–15.3 kT) indicates that IL can suppress bubble formation. This work has gained a fundamental insight into the dynamic formation behaviors of H 2 nanobubble in IL, which can guide us to study H 2 bubbles in the HER influenced by various factors.
研究领域:
化学
·
电化学
·
材料科学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）