CRYSTAL GROWTH & DESIGN
·
2021
·
IF 4.076
Haoyu Peng,Ningning Tian,Changyou Yu,Ye Gao,Kangli Li,Hui Yan,Pengwei Zhao,Songgu Wu,Mingyang Chen,Junbo Gong
The experimental metastable zone widths of PE–DPE–H2O systems were measured by a polythermal method, and the nucleation behavior of pentaerythritol (PE) and the influence of dipentaerythritol (DPE) on the critical nucleus parameters were analyzed on the basis of modified Sangwal’s model and classical nucleation theory, respectively. The results reveal that the dissolved DPE molecules can significantly increase the nucleation solid–liquid interfacial energy γ from 3.93 to 5.51 mJ/m2, increasing the critical nucleus size rcrit and free energy ΔGcrit, and inhibit the nucleation process.
研究领域:
化学
·
材料科学
✓ 已验证
DOI
高影响因子
Journal of Energy Storage
·
2024
·
IF 8.9
Xuanxuan Wang,Yuting Wu,Chuan Li,Yuanwei Lu,Cancan Zhang,Ming Hong
As one of classic organic compounds, pentaerythritol (PE) has been reported to have two phase-change processes with one solid-solid transition and other solid-liquid transition. To utilize these two phase-change enthalpies and avoid the liquid leakage over heat storage process, this work for the first time proposes to encapsulate PE with use of silicon dioxide (SiO 2 ) as a shell substance through a so-called so-gel technology. The microstructure characterization and thermoproperties as well as the cycling performance of the PE- SiO 2 composite are detailedly investigated. The results showed that PE could be successfully covered by SiO 2 to form a spherical core-shell structure. Such an encapsulation has a mean size of 0.3 μm and an encapsulated rate of over 77.8 %. Due to the involvement of two phase-transition stages, the latent heat of the PE- SiO 2 composite reached to 255 kJ/kg, which is higher than other organic microencapsulations. In addition, the thermal conductivity is largely enhanced by adjusting the ratio of SiO 2 . For a given SiO 2 ratio of 77.8 %, the thermal conductivity of PE-SiO 2 composite is 0.93 W/m·K, 36.8 % higher than that of pristine PE. Apart from these, the results also indicated that the composite achieves excellent thermal cycling performance. After one hundred repeated heating-cooling cycles, the latent heat of the PE- SiO 2 composite decreases by less than 5 %, demonstrating that this composite material has a large potential for application in the field of thermal energy storage at low and medium temperatures.
研究领域:
材料科学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
ENERGY
·
2023
·
IF 9
Chu Huang,Haixi Zhu,Yinjie Ma,Jiaqiang E
Immersion cooling is an effective way to control the thermal load of high-power-density energy storage devices. Developing high-efficiency coolants is the core problem and research hotspot to improve immersion cooling performance. In this study, a novel ester coolant, pentaerythritol esters, for battery immersion cooling systems (BICS) was proposed by experiment, and its thermal properties were comparatively studied with other coolants. The effect of coolant flow rate and discharge rate on the thermal performance of BICS was studied. An increase in the discharge rate results in an increase in the maximum battery pack temperature and temperature non-uniformity. However, at a 3-C discharge rate, pentaerythritol esters with a flow rate of 0.015 kg/s can keep the temperature difference of the battery pack below 0.7 K. When the flow rate increases from 0.003 kg/s to 0.045 kg/s, the temperature rise of the battery pack can be reduced by 61%. For all coolants, when the flow rate increases from 0.025 kg/s to 0.045 kg/s, the power consumption increases by 2.3 times. Compared with mineral oil, at a flow rate of 0.045 kg/s, pentaerythritol esters can reduce power consumption by 55.4%. Combined with its renewable, biodegradable features, the novel pentaerythritol ester is a perfect option for the battery immersion coolant.
研究领域:
能源工程
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材料科学
·
热力学
✓ 已验证
DOI
高影响因子
Polymers
·
2019
·Vol. 11
·期 2
·194
·
IF 3.164
Feng Ye,Qiufeng Ye,Haihua Zhan,Yeqian Ge,Xiaotao Ma,Yingying Xu,Xu Wang
Zinc orotate (ZnOr2), which is a new kind of poly(vinyl chloride) (PVC) stabilizer, is prepared in this work through the precipitation method, and its impact on the thermal stability of PVC is measured by thermogravimetric analysis (TG), Congo red test, and discoloration test. The results exhibit that the thermal stability of PVC is positively enhanced after the addition of ZnOr2. In contrast with a commercial thermal stabilizer, zinc stearate (ZnSt2), a noteworthy improvement was observed that ZnOr2could postpone the “zinc burning” of PVC. This is principally ascribed to the Or anion in the structure of ZnOr2being able to absorb the HCl released by PVC, and to supersede unstable chlorine atoms in the structure of PVC. In addition, blending ZnOr2with calcium stearate (CaSt2) in diverse mass ratios can significantly accelerate the thermal stability of PVC. Optimum performance was achieved with a CaSt2:ZnOr2ratio of 1.8:1.2. Moreover, an outstanding synergistic effect can be observed when CaSt2/ZnOr2is coupled with other commercial auxiliary stabilizers. The initial color and long-term stability of PVC including CaSt2/ZnOr2is significantly increased when pentaerythritol (PER) is added, while dibenzoylmethane (DBM) can only improve its long-term thermal stability.Keywords:poly(vinyl chloride);zinc orotate;dibenzoylmethane;thermal stabilizer;pentaerythritol;synergistic effect
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ChemistrySelect
·
2024
·Vol. 9
·期 22
·e202401172
·
IF 1.9
Miao Mi,Jie Xiong,Suhong Zhang,Yidong Zhang,Xin Chen,Rong Shao,Wei Xu,Jianfei Ding
Graphical Compared to SnCl 2 and HZSM-5, SnCl 2 @HZSM-5 was a mesoporous composite, which had the most amount of total and weak acidity, and the weakest acid strength. More total acid content is beneficial to increase pentaerythritol conversion, and the weak acid can improve the selectivity of PETS, and weak acid strength is beneficial to inhibit the formation of carbon deposits. Therefore, SnCl 2 @HZSM-5 showed the highest pentaerythritol conversion, PETS selectivity and catalytic stability. The mesoporous HZSM-5 and SnCl 2 @HZSM-5 mesoporous composite were prepared by two-step crystallization and wet impregnation method, respectively. The catalytic esterification performances of SnCl 2 , HZSM-5 and SnCl 2 @HZSM-5 were compared. SnCl 2 @HZSM-5 had the most amount of total and weak acidity, and the weakest acid strength. More total acid content was beneficial to increase pentaerythritol conversion, and the weak acid could improve the selectivity of PETS, and weak acid strength was beneficial to inhibit the formation of carbon deposits. Brönsted and Lewis acid sites were present simultaneously on the SnCl 2 @HZSM-5 catalyst. Moreover, some extra Brönsted acid sites were created on the SnCl 2 @HZSM-5 catalyst, because the interaction of SnCl 2 with HZSM-5 may result in the exchange of Sn 2+ with protons. Both acid sites could catalyze the esterification reaction, and the Brönsted acid site was more beneficial to increasing PETS selectivity. Therefore, SnCl 2 @HZSM-5 showed the highest pentaerythritol conversion, PETS selectivity and catalytic stability. The generation of coke and the leaching of Sn were the main cause of catalyst deactivation. Under the optimized process conditions: 105 °C, 4.7 molar ratio of stearic acid and pentaerythritol, 1.2 wt % catalyst amount and 2.5 wt % SnCl 2 loading, after 3 h reaction time, the pentaerythritol conversion, PETS selectivity and yield was 99.3 %, 97.2 % and 96.5 %, respectively.
研究领域:
化学工程
·
催化科学
✓ 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）