THERMOCHIMICA ACTA
·
2024
·
IF 3.1
Shuhang Li,Xianglin Liao,Zhinan Zhang,Xue Chen,Luobiao Hong,Cong Liu,Suilian Luo,Qiong Hou,Yuhai Wang,Guang Shi
The thermal stability of zeolitic imidazolate framework-8 (ZIF-8) for poly(vinyl chloride) (PVC) has received attention, but its thermal stabilization mechanism needs further clarification. Herein, the stearic acid-modified ZIF-8 with high specific surface area and large pore volume was effectively synthesized by using zinc stearate as the zinc source for the first time. Modification of stearic acid results in larger adsorption capacity of ZIF-8 for HCl and better thermal stability effect for PVC, especially long-term thermal stability. Moreover, the thermal stability mechanism of ZIF-8 for PVC was demonstrated by experiments and theoretical calculations. In addition to absorbing HCl to eliminate autocatalytic degradation of PVC, ZIF-8 disintegrates and may form 2-methylimidazole-Zn-Cl salt complex instead of free ZnCl2, avoiding the negative zinc burning effect. Furthermore, the Diels-Alder reaction between imidazole ring and degraded PVC prevents the extension of the conjugated double bonds of PVC and delays the deepening of the color of PVC.
研究领域:
材料科学
·
高分子化学
·
热力学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Yi Pan,Yu Liu,Xiaomin Zhang,Mingzhen Shi,Zhuoheng Tu,Xingbang Hu,Youting Wu
The exploiting of efficient, reversible and environmentally friendly hydrogen chloride (HCl) absorbent is of great significance for the recovery and high-value utilization of by-product HCl. Herein, we propose a new strategy to design deep eutectic solvents (DESs) with multiple-active-sites to effectively absorb HCl. Therefore, five new DESs were designed and prepared by pairing 1,3-dimethyl-2-imidazolidinone (DMI) with amide derivatives or LiCl. Among them, DMI + 1,3-dimethylurea (2:1) showed the unprecedented HCl capacity of 2.16 mol/mol at 303.2 K and 1 bar, surpassing that of water, DESs and ILs reported in literature. Spectroscopic characterization and quantum-chemical calculations showed that such high HCl capacity originates from multiple interaction sites between DESs and HCl. DMI + 1,3-dimethylurea (2:1) also exhibited the advantages of fast absorption of HCl, good recyclability, good selectivity and acceptable cost. A new reaction equilibrium thermodynamic model was developed to correlate HCl solubility data. The absorption rate of HCl in DESs was measured systematically for the first time. These DESs with multiple-active-sites offer improvements over commonly used absorbents, indicating the promise for industrial application in HCl separation and storage.
研究领域:
化学工程
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环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS SCIENCE FORUM
·
2021
·
IF 0
Mansurjon Juraev,Xiao Ya Zhou,Xiao Tao Ma,Cheng Fang,Ye Qian Ge,Qiu Feng Ye,Feng Ye
The structure of basic lanthanum orotate (LaOr) were characterized by elemental analysis and infrared spectroscopy. The thermal stability of polyvinyl chloride (PVC) was further studied by Congo red method, oven discoloration method and thermogravimetric analysis. The results showed that LaOr could prolong the oven discoloration time of PVC, and the color was not completely blackened until 120 min. It has a good synergetic effect with dibenzoyl methane (DBM), and the best effect is achieved when LaOr/DBM ratio is 1.8/1.2. The thermal decomposition kinetics experiment showed that adding DBM can effectively improve the activation energy of PVC/LaOr. The stabilization mechanism of PVC was studied by absorbing HCl method and infrared spectroscopy. The results showed that LaOr could not only replace the unstable chlorine atoms on PVC, but also promote the long-term thermal stability of PVC by absorbing HCl.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
POLYMER DEGRADATION AND STABILITY
·
2019
·
IF 3.78
Xu Wang,Biao Ma,Yating Wang,Songyan Lu,Meng Ma,Yanqin Shi,Si Chen
A totally new theory of “two-step stabilization mechanism” for triazole-based zinc-containing complex (abbreviated as [Zn(ttr)(OAc)]) was proposed through several designed experiments. [Zn(ttr)(OAc)] strongly absorbed HCl at the beginning, and then broke down into 3-amino-1,2,4-triazole which could further stabilized PVC . The structure of [Zn(ttr)(OAc)] was characterized by FTIR spectroscopy , elemental analysis and SEM. Then, Congo red tests and discoloration tests verified [Zn(ttr)(OAc)] could absorb HCl effectively, but PVC showed poor initial whiteness, which further proved above-mentioned stabilization mechanism. Moreover, [Zn(ttr)(OAc)] combined with ZnSt 2 and dibenzoyl methane (DBM) effectively improved the initial color of PVC samples and provided PVC with shorter plasticizing time and longer dynamic thermal stability time than commercial stabilizer 1086F, confirmed by discoloration tests and dynamic thermal stability analysis. We believe [Zn(ttr)(OAc)]/ZnSt 2 /DBM stabilizer system can be used as a commercial stabilizer and the stabilization mechanism of [Zn(ttr)(OAc)] may provide a new way to stabilize PVC.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2015
·Vol. 122
·期 3
·1435-1444
·
IF 2.042
Xu Xiaopeng,Chen Si,Shi Yanqin,Wu Bozhen,Ma Meng,Wang Xu
A novel kind of antibacterial thermal stabilizers for transparent poly(vinyl chloride), bis-uracil compounds with different alkyl chain length, was synthesized by the condensation of 6-amino-1,3-dimethyluracil with aliphatic aldehydes and characterized with 1 H NMR spectra. Not only high stabilization efficiency which increased with the increasing of alkyl chain length was obtained to prevent PVC from degradation, special antibacterial properties could also be acquired in the mean time of keeping PVC highly transparent. The results of discoloration test, thermogravimetric analysis, Fourier transform infrared spectra, visible spectroscopy and scanning electron microscopy revealed that the bis-uracil compounds could absorb HCl through acid–base reaction and chemical bonding, and the amine group played a key role in reacting with the inherent structural defects in PVC chains, meanwhile the long alkyl chain of the bis-uracil compounds could reduce their melting points and improve the compatibility with PVC. Comparing with the referential films stabilized by 6-amino-1,3-dimethyluracil and Ca/Zn stabilizers, PVC films stabilized with bis-uracil compounds had excellent transparency. In addition, the measurement of antimicrobial activity suggested that the bis-uracil compounds had the biological activity to inhibit growth of bacteria. We believe that PVC stabilized by such multifunctional stabilizers may widen its applications in biomedical field.
研究领域:
材料科学
·
生物学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2025
·
IF 2.8
Yilin Li,Jinsheng Duan,Zhaogang Liu,Feng Guo,Peijie Jia,Junchang Fan,Shuxin Wu,Yanhong Hu,Jinxiu Wu,Xiaowei Zhang,Jianfei Li
To address the thermal instability of polyvinyl chloride (PVC) and the environmental risks of conventional stabilizers, cyanurate-intercalated layered double hydroxides (LDHs), including MgAl-LDH (MA), La-doped MgAl-LDH (MAL), and Ca/La-doped MgAl-LDH (CMAL), were synthesized. Comprehensive XRD, FTIR, TGA, and SEM characterization confirmed the structural integrity of the samples. These LDHs were incorporated into PVC to fabricate composite materials, whose thermal stabilization efficiency was systematically evaluated through accelerated aging, Congo red, and dynamic thermal stability tests. Thermogravimetric analysis revealed that CMAL/PVC exhibited the highest initial decomposition temperature (281°C), surpassing MA/PVC (270°C), MAL/PVC (274°C), and neat PVC (256°C). Consistent enhancements were observed in color retention and HCl scavenging capacity, which correlated with increased thermal degradation resistance. Mechanistic studies demonstrated that cyanuric acid-modified LDHs effectively suppressed autocatalytic HCl elimination and conjugated polyene formation during the thermal aging process at 180°C and the HCl absorption experiment. The multimetal synergy in CMAL enhanced Cl − coordination and acid neutralization, thereby inhibiting PVC degradation cascades. This work provides fundamental insights into designing eco-friendly LDH-based thermal stabilizers for high-performance PVC applications, demonstrating significant potential for sustainable polymer engineering.
研究领域:
材料科学
·
高分子科学
·
环境科学
·
化学工程
✓ 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）