JOURNAL OF HAZARDOUS MATERIALS
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2023
·
IF 13.6
Qingyang Luan,Han Hu,Xiaoyu Jiang,Chen Lin,Xiaoqin Zhang,Qianfeng Wang,Yunxiao Dong,Jinggang Wang,Jin Zhu
Marine plastic pollution , with annual emissions into the marine over 53 million metric tons, has been a major worldwide concern. Many of so-called “biodegradable” polymers degrade very slowly in seawater. Oxalate have attracted attention because the electron-withdrawing effect of adjacent ester bonds promotes their natural hydrolysis, particularly in the ocean. However, the low boiling point and poor thermal stability of oxalic acids severely limits their applications. The successful synthesis of light-colored poly(butylene oxalate-co-succinate) (PBOS), with weight average molecular weight higher than 1 × 10 5 g/mol, displays the breakthroughs in the melt polycondensation of oxalic acid-based copolyesters. The copolymerization of oxalic acid retains the crystallization rate of PBS, with minimum half-crystallization times from 16 s (PBO 10 S) to 48 s (PBO 30 S). PBO 10 S-PBO 40 S exhibit good mechanical properties with elastic modulus of 218–454 MPa, and tensile strength between 12 and 29 MPa, better than packaging materials such as biodegradable PBAT and non-degradable LLDPE . PBOS achieve rapid degradation in the marine environment, with a mass loss 8%− 45% after 35 days. The characterization of structural changes demonstrate that the introduced oxalic acid plays a key role in the process of seawater degradation. This new class of polymers therefore provide highly promising materials for sustainable packaging with unique seawater degradation properties.
研究领域:
材料科学
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环境科学
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产品关联
DOI
PubMed
高影响因子
Polymer Chemistry
·
2017
·Vol. 8
·期 45
·7009-7016
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IF 5.375
Shi-He Luo,Yan-Cheng Wu,Liang Cao,Qun-Fang Wang,Shui-Xia Chen,Zhi-Feng Hao,Le Jing,Zhao-Yang Wang
A series of polylactic acid-ibuprofen (PLA-IBU) conjugates was directly synthesized via melt polycondensation of lactic acid (LA) with ibuprofen (IBU) in the presence of 0.3 wt% SnO at 160 °C for 6 h. The structures of the PLA-IBU conjugates were confirmed by FTIR and 1H NMR. According to the GPC and DSC results, the molecular weight and Tg of the PLA-IBUs with different feed ratios increase as the feed amount of LA increases. The drug content of these IBU-conjugated biodegradable polymers can also be simply controlled by adjusting the monomer feed ratio to reach the expected levels. The preliminary biological tests show that the PLA-IBU conjugates have the anticipated pharmaceutical activity, which is beneficial for these PLA-based IBU prodrugs prepared by this convenient one-pot method to be efficiently used in the biochemical and pharmaceutical industry.
研究领域:
材料科学
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药学
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DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
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2022
·Vol. 140
·期 5
·e53418
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IF 3.057
Mengdi Chen,Mingfu Zheng,Lu Zhang,Yunsheng Xu,Xianming Zhang,Wenxing Chen
In this work, multiple rheological and molecular structure characterization methods are utilized to investigate the melt post-polycondensation (MPP) process of polycarbonate (PC) at high temperatures (260–300°C) under a nitrogen atmosphere. We find some unexpected phenomena that the complex viscosity of PC melt rise rapidly and it reaches an extraordinarily high value of about 10 6 Pa·s during the MPP process of 10 h at 300°C. Dissoluble PC and insoluble gel residue are separated and both fractions are analyzed by gel permeation chromatography, 1 H-NMR, and pyrolysis-gas chromatography mass spectrometry. Results show that the molecular weight of dissoluble PC significantly increases at the early stage of the reaction (less than 1 h). After that, it continues to reduce due to the occurrence of branching reactions and degradation reactions caused by high temperature reactions for a long time. Chemical structure analysis indicates that the same two branched structures are discovered in both dissoluble PC and insoluble gel residue, the changes in structures indicate that no new structures are formed during the crosslinking reaction. According to this study's results, we clearly understand the correlation between the rheological properties and structural changes for PC in the MPP progress.
研究领域:
材料科学
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高分子化学
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产品关联
DOI
高影响因子
POLYMER
·
2022
·
IF 4.432
Qisong Lin,Feng Gao,Yongjun Wang,Wangyang Lu,Wenxing Chen
Antimony-free poly(ethylene terephthalate) (PET) has been synthesized through polycondensation of p -phthalic acid and ethylene glycol , and then subjected to a viscosity-increasing process by liquid-state polycondensation (LSP). For both of these processes, a novel environmentally benign ethylene glycol-soluble Ti/Mg bimetal (TM) catalyst has been used. The structure of the TM catalyst has been comprehensively characterized and its catalytic activity in the polycondensation reaction has been evaluated and compared with those of other titanium-based catalysts. The results reveal that the TM catalyst is a chelated complex with high catalytic activity for polycondensation to afford PET without significant side reactions. Indeed, the LSP process catalyzed by TM affords a PET product with high intrinsic viscosity suitable for industrial yarn production (1.08 dL/g) within 60 min, and that exhibits higher thermostability with increasing intrinsic viscosity. Finally, the kinetics of the TM-catalyzed polycondensation has been probed based on the variation of intrinsic viscosity with increasing polycondensation time.
研究领域:
材料科学
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聚合物化学
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催化
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环境科学
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产品关联
DOI
高影响因子
EUROPEAN POLYMER JOURNAL
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2021
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IF 4.598
Qiaohong Peng,Li Wei,Xiaoyan Zhang,Ying Wu,Khalid Mahmood,Zhengping Liu,Lisha Zhang
Ionic liquids (ILs), instead of the classical organic solvents, have shown great improvements in chemical processes. Herein, Water-insoluble alkyl- and benzyl-substituted imidazolium bis(trifluoromethanesulfonyl)imides as non-volatile and thermostable solvents were employed in the direct polycondensation of l -lactic acid (LLA). The effects of monomer concentration, reaction temperature and miscibility between the ILs and poly( l -lactic acid) (PLLA) were comprehensively investigated. Biodegradable PLLA with weight-average molecular weight as high as 132 kDa was synthesized. Compared to melt-polycondensation of LLA, far higher molecular weight could be achieved via the solution polycondensation of LLA in ILs since the viscosity of the polymer melt could be significantly reduced based on the dilution effect of ILs. Polycondensation kinetics of LLA in bulk and in an IL demonstrated that the IL could accelerate the polycondensation of LLA. Influence of lactide, the main by-product, on the polycondensations of LLA was also studied kinetically.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
Polymers
·
2018
·Vol. 10
·期 11
·1287
·
IF 2.935
Wenmeng Zhang,Shaoyun Chen,Dongyang Chen,Zhuoliang Ye
Sterically hindered (S)-1,1′-binaphthyl-2,2′-diol had been successfully copolymerized with 4,4′-sulfonyldiphenol and 4,4′-difluorobenzophenone to yield fibrous poly(arylene ether ketone)s (PAEKs) containing various amounts of binaphthyl unit, which was then selectively and efficiently sulfonated using ClSO3H to yield sulfonated poly(arylene ether ketone)s (SPAEKs) with ion exchange capacities (IECs) ranging from 1.40 to 1.89 mmol·g−1. The chemical structures of the polymers were confirmed by 2D1H–1H COSY NMR and FT-IR. The thermal properties, water uptake, swelling ratio, proton conductivity, oxidative stability and mechanical properties of SPAEKs were investigated in detail. It was found that the conjugated but non-coplanar structure of binaphthyl unit endorsed excellent solubility and film-forming capability to SPAEKs. The SPAEK-50 with an IEC of 1.89 mmol·g−1exhibited a proton conductivity of 102 mS·cm−1at 30 °C, much higher than that of the state-of-the-art Nafion N212 membrane and those of many previously reported aromatic analogs, which may be attributed to the likely large intrinsic free volume of SPAEKs created by the highly twisted chain structures and the desirable microscopic morphology. Along with the remarkable water affinity, thermal stabilities and mechanical properties, the SPAEKs were demonstrated to be promising proton exchange membrane (PEM) candidates for potential membrane separations.Keywords:proton exchange membranes;condensation polymerization;post-sulfonation;binaphthyl;film-forming capability
研究领域:
材料科学
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化学工程
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产品关联
DOI
PubMed
高影响因子
POLYMER
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2024
·
IF 4.1
Caiqi Liu,Fei Liu,Tao Yang,Caohong Chen,Yanyan Lin,Jinggang Wang,Jin Zhu
The preparation of copolymers containing lactyl unit by direct melt polymerization of lactic acid has been a big challenge, especially for those with high molecular weight ( M n ). In this paper, lactic acid was converted to bifunctional monomer ( i.e. SLA) suitable for direct polycondensation via alcoholysis of cyclic anhydride. A series of PBALT copolyesters were synthesized by replacing adipic acid with SLA in order to introduce lactyl unit to poly(butylene adipate- co -terephathalate) (PBAT) for enhanced barrier property and biodegradability. Results showed that a series of PBALT copolyesters with high M n of more than 41 000 g/mol can be successfully synthesized. The elongation at break remained high as the SLA content increased, while the melting temperature, the tensile modulus and strength gradually decreased. More importantly, the water vapour and gas barrier (towards CO 2 and O 2 ) property were increased by a factor of up to 1.62 and 4.3–4.4, respectively. In addition, the compost and enzymatic degradation rates of the copolyesters were accelerated by the introduction of the lactyl unit, which is mainly due to the reduction of the crystallinity. This study provides a facile strategy for the direct polycondensation of lactic acid, rather than using lactide, and thus establishes a new method for the development of biodegradable copolyesters containing lactyl unit with enhanced properties.
研究领域:
材料科学
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高分子化学
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产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
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2022
·Vol. 139
·期 28
·e52513
·
IF 3.057
Chenxi Lin,Kangzhou Xie,Donglin Tang
Polyureas (PUrs) with excellent properties have been applied widely in many fields. These days attention has been turned to non-isocyanate routes for PUr preparation due to the toxicity and the high cost of isocyanates. Urea is a green chemcial which can be either from urine or from recycled carbon dioxide and ammonia. Here we introduce a urea-based route to prepare PUrs, by melt polycondensation of urea and 1,10-diaminodecane (DA-10) or/and 1,6-diaminohexane (DA-6) without catalyst, solvent, and high pressure. It is difficult to synthesize such thermoplastic PUrs from diisocyanate without any solvent since the melting point of PUr is normally higher than 170°C at which isocyanate is able to react with urea group to form biuret. The thermoplastic PUrs obtained in this study exhibit excellent mechanical and thermal properties. Furthermore, the properties can be adjusted by changing the feed ratio of diamines (DA-6/DA-10). The compression-molded PUrs show even better mechanical properties than ultra-high molecular weight polyethylene (UHMWPE). The values of Young's modulus, strength at break and elongation at break are found to be 230–300 MPa, 40–60 MPa and 200%–400%, respectively (except for PUr-6). Therefore, this facile, non-isocyanate approach provides a viable alternative to the current industrial process for high-performance PUrs.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2024
·
IF 3.8
Haoze Wang,Huizhe Zheng,Jie Jiang,Ling Zhao,Zhenhao Xi
Poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate) (PCTG) is a high-performance engineering copolyester prepared using terephthalic acid (TPA), ethylene glycol (EG), and 1,4-cyclohexanedimethanol (CHDM). In this work, a complex reaction network of PCTG copolyesters involving homopolymerization and cross-polymerization was presented and the corresponding reaction mechanism was proposed. The reaction kinetics and mass transfer behavior were investigated using static thin film experiments, wherein the variation of the hydroxyl end-group concentrations of EG and CHDM with reaction time was separately determined. The results showed that the apparent reaction rate benefited from the high temperature, thin film thickness, and high vacuum conditions. Based on the pseudosteady-state assumption, the apparent reaction rate model coupled with mass transfer was evaluated and the model parameters including the reaction rate coefficient, equilibrium constant, and mass transfer coefficient were obtained, which were further used to simulate the polycondensation process. The concentration variation of EG and CHDM, and the rate variation of each reaction during polycondensation are discussed by combining the effects of homopolymerization, cross-polycondensation, and mass transfer. The concentration of EG was more sensitive to pressure than that of CHDM, which promoted the production of CHDM at high pressures. The proposed model is expected to provide guidance for the optimization of industrial production of PCTG/PETG and generalize to other copolyester systems.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
Materials
·
2023
·Vol. 16
·期 9
·3296
·
IF 3.4
Wenqi Zou,Hongli Bian,Jinjing Guo,Jun Xu,Baohua Guo
Titanates are widely used in the synthesis of polyesters, such as Poly (butylene succinate) (PBS), due to their excellent catalytic activity for polycondensation. However, the hydrolysis sensitivity of titanate and side reactions at high temperatures restrict the further improvement of the molecular weight of polyesters and lead to the high content of end carboxyl group content in the products. In this work, we prepared titania–silica composite aerogels with resistance to hydrolysis and large specific surface area, which were further explored as an efficient catalyst for polycondensation reactions. A series of titania–silica composite aerogel catalysts for PBS polycondensation were successfully prepared by the sol-gel method. The influence of a Ti/Si ratio on the surface morphology and structure of the aerogels was examined. Titania–silica composite aerogel exhibits the surface characteristics of high specific surface area and high Lewis acid content. The specific surface area of titania–silica composite aerogels can reach 524.59 m2/g, and the Lewis acid content on the surface can reach 370.29 μmol/g. Furthermore, the catalytic performance for the polycondensation reaction of PBS was investigated. The intrinsic viscosity of PBS synthesized by catalysis with the composite catalyst with a Ti/Si ratio of 9/1 reaches 1.74 dL/g, with the Mnof 7.72 × 104g/mol. The hydrolysis resistance stability of the titania–silica composite aerogel is greatly improved compared with traditional tetrabutyl titanate (TBT), and the end carboxyl group content of PBS is effectively reduced to lower than 30 mol/ton.Keywords:Poly (butylene succinate);aerogel;catalysts;titanates;polycondensation
研究领域:
材料科学
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催化化学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF CHROMATOGRAPHY A
·
2019
·
IF 3.858
Rongguo Chen,Chenchen Lin,Haixia Lyu,Xucong Lin,Zenghong Xie
A facile strategy for highly efficient fabrication of chiral monolithic column was carried out by the simple “one-pot” hydroxymethyl polycondensation of native β-cyclodextrin (β-CD) and urea-formaldehyde (UF). In-situ rapid substitution of native β-CD and efficient polycondensation of β-CD products and UF oligomers was proposed and fulfilled in one pot. The feasibility, mechanism and key parameters of polycondensation reaction were discussed. The data on crosslinking polycondensation and reaction kinetics were further evaluated. Characteristics including the morphologies, permeability and structure stability of the resultant monolithic columns were also studied. Under the optimal conditions, the “one-pot” hydroxymethyl polycondensation was accomplished in an aqueous solution within only 10 mins. Satisfactory stability and repeatability were gained, and good enantioseparation of eight model enantiomers was successfully achieved with the resultant β-CD-based monolith. It was simple and highly efficient, and the organic solvents, special CD derivatives and tediously long-time polymerization reaction were successfully avoided, which might light a new access to rapid preparation of CD-chiral monolith for high-performance enantioseparation.
研究领域:
分析化学
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色谱技术
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DOI
高影响因子
HIGH PERFORMANCE POLYMERS
·
2023
·
IF 2.1
Huanhuan Gao,Xiaozhou Zhang,Xigao Jian,Jinyan Wang
In this study, the melt polycondensation reaction of 9,9’- bis(4-hydroxyphenyl)fluoride (BHPF) and diphenyl carbonate (DPC) was catalyzed using three ionic liquids (ILs) and a conventional alkali metal as catalysts. The optimal IL catalysts were determined to be [BMmim][BF4] ionic liquid catalysts, and the catalytic mechanism was investigated. Furthermore, the optimum process conditions were identified: the optimal amount of [BMmim][BF4] was 0.05 mol% based on DPC, the polycondensation temperature was set at 200°C for a duration of 3 h, followed by polymerization at 280°C for another 3 h. As a result, the Mn value of poly(9,9-bis(4-hydroxyphenyl) carbonate) (PFC) reached up to 41387 g/mol with a glass transition temperature band of approximately 254°C and Td-5% value of around 436°C.
研究领域:
材料科学
·
化学工程
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DOI
高影响因子
危险品化学品经营许可证（带存储）