JOURNAL OF HAZARDOUS MATERIALS
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2025
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IF 11.3
Simeng Li,Xiaohui Li,Chen Zhang,Bowen Li,Peiwen Yu,Qin Dai,Hongping Wang,Fen Jin
Trisiloxane ethoxylates (TSEO n ) have been found in multiple agro-environmental media due to their pervasive application in agricultural production. While some studies suggested that the differences in the toxicological effects of TSEO n were closely related to their end-capping groups, the environmental behaviors and fate of TSEO n congeners with varying end-capping groups in agroecosystems remain underexplored. This study investigated the dissipation patterns of 39 oligomers across three TSEO n congeners in cucumber, leaves, and soils through field trials, including TSEO n -H (hydroxy, n = 2 to 14), TSEO n -CH 3 (methoxy, n = 2 to 14), and TSEO n -COCH 3 (acetoxy, n = 3 to 15). All TSEO n oligomers dissipated following pseudo-first-order kinetics in cucumber, leaves, and soils with half-lives were 2.08-3.92 d, 1.77-4.44 d, and 5.06-19.80 d, respectively. TSEO n congeners in agro-environmental media presented different dissipation patterns affected by their end-capping groups. The interfacial behaviors of TSEO n -COCH 3 in the leaves differed from those of TSEO n -H and TSEO n -CH 3 . The half-lives of TSEO n -H and TSEO n -CH 3 congeners in soils were significantly positively correlated with log K OC , indicating that long-chain congeners preferentially partition to soil solid phases, leading to slower dissipation rates than short-chain congeners. Furthermore, long-chain TSEO n congeners may dissipate to short-chain congeners. The dietary risks of ΣTSEO n -CH 3 intake through cucumber fruits were deemed safe for different Chinese populations based on the margin of exposure (MOE) assessment. This study alerts us to the environmental behaviors and fate of organosilicone surfactants and provides a baseline reference to the dietary exposure risks of TSEO n .
研究领域:
环境科学
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农业科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2022
·Vol. 139
·期 43
·e53061
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IF 3.057
Binglun Gao,Lianwei Sun,Xin Chen,Xiaobo Zhai,Junchi Zheng,Xin Ye,Jianmin Lu,Anchao Feng,Liqun Zhang
The focus of this paper is to report the quantitative synthesis of bis-epoxy end functionalized polyisoprene (BETPI) macromonomers by anionic polymerization and reversible addition fragmentation chain transfer (RAFT) polymerization. For anionic polymerization, more stable and sterically hindered living anions polyisoprene (Li + -PIp-Li + ) react with epichlorohydrin (ECH) for the synthesis of well-defined BETPI. For the high-pressure RAFT polymerization, a novel bis-epoxy end functionalized trithiocarbonate (BODAAT) is designed as RAFT agent for the polymerization of isoprene monomer to obtain well-defined BETPI. The functionalities of the resulting BETPI are analyzed by Fourier transform infrared spectroscopy (FT-IR), NMR, and size exclusion chromatography (SEC). Through two polymerization methods, the BETPI with 600–1000 Da of molecular weight and over 75% of epoxy end capping rate is obtained, which can be further utilized as highly reactive liquid macromonomers.
研究领域:
高分子化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
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IF 13.3
Rongxiang Hu,Fenghua Zhang,Lan Luo,Linlin Wang,Yanju Liu,Jinsong Leng
Shape memory polymers (SMPs) with elevated switching temperatures and enduring thermal properties are highly desirable yet challenging in certain aerospace applications. In this study, high-temperature shape memory phthalonitrile resins (SMPNs) were developed using an end-capping strategy with the uniphthalonitrile (UPN) as the end-capping reagent to modulate the density of the cross-linked network. The resultant SMPNs exhibit a glass transition temperature (Tg) at approximately 300 °C, with a shape fixation rate of about 98 % and a shape recovery rate around 97 %. Importantly, these SMPNs also demonstrated exceptional thermal stability, with a thermal decomposition temperature exceeding 445 °C. Additionally, an oxyacetylene ablative test revealed the SMPNs' robust ablative resistance, as the linear ablation rate remained below 0.1 mm/s and the mass ablation rate was less than 0.1 g/s. The commendable shape memory performance and superior high-temperature resistance allowed the SMPNs to successfully undergo the shape recovery process when subjected to a butane flame. Furthermore, after a high-temperature annealing process, the SMPNs exhibited electrical conductivity due to graphitization, even possessing wave-absorbing properties within a specific frequency range. It is foreseeable that these multifunctional SMPNs will have extensive applications in the aerospace sector, given the advancement of smart structures.
研究领域:
材料科学
·
航空航天工程
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2018
·
IF 3.483
Pibo Liu,Hongwei Ma,Li Han,Lincan Yang,Heyu Shen,Chao Li,Yang Li
Three amine-functionalized 1,1-diphenylethylene (DPE) derivatives (DPE-(NMe 2 ) 2 , DPE-NMe 2 and DPE-SiH/NMe 2 ) were used to study the end-capping reactions of poly(styryl)lithium (PS-Li) for investigating the effect on end-capping of electron-donating groups in DPE structures. In situ 1 H NMR was used to measure the kinetic parameters of end-capping reactions. When the DPE derivative was held constant in the PS-Li capping reaction, the kinetic parameter (k SD ) did not change with the variance of either concentration or degree of polymerization of PS-Li. Additionally, the k SD value changed dramatically when various electronic properties of the DPE derivative substituents were modified. Electron-withdrawing groups accelerated the end-capping reaction, while electron-donating groups decelerated it. The k SD experimental values of DPE-(NMe 2 ) 2 , DPE-NMe 2 and DPE-SiH/NMe 2 were found to be 0.155 × 10 −3 , 1.26 × 10 −3 , and 6.24 × 10 −3 L 1/2 mol −1/2 s −1 , respectively. An intuitive model was established to simulate the precision of the sequence-controlled copolymerization with DPE derivatives based on investigations of end-capping kinetics. The model depicts the degree of fictitious styrene propagation for the chain insertion of one DPE derivative unit. The fictitious degrees of polymerization of styrene (FDPs) for DPE-NMe 2 and DPE-SiH/NMe 2 were calculated to be 37 and 13, respectively, suggesting that using DPE derivatives containing an electron-withdrawing group in the synthesis of sequence-controlled polymers might lead to a more precise structure.
研究领域:
高分子化学
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材料科学
✓ 已验证
DOI
高影响因子
EUROPEAN POLYMER JOURNAL
·
2023
·
IF 6
Yuan-Yuan Liu,Jian-Hua Cao,Yue Li,Ya-Kun Wang,Da-Yong Wu
In this work, we use 2-aminobenzimidazole and 2-aminobenzoxazole to end-cap colorless polymer, PAI TFDB-TPC-6FDA, in order to investigate methods for reducing the CTE value of products and their effects on other properties. Results show that, as the ratio of 2-aminobenzimidazole to the raw material, diamine TFDB, increases from 0:100 to 2:99, the CTE value of products gradually decreases from 20.0 to 12.9 ppm/K (a decrease of 36%). Nevertheless, the CTE value of products rebounds as the dosage of the end-capped groups exceeds this ratio. Among all the products obtained, PAI-1M film has the best overall properties: its CTE is 12.9 ppm/K, T d 5 is 518 ℃, T g is 366 ℃, T S is 191 MPa, T 430 is 85.1%, W A is 85.4% and C A is 0.8%. The two end-capped groups are of highly linear and rigid structures. They also help to enhance the hydrogen bonding between molecules, resulting in a decrease in d -spacing values. The results of molecular configuration simulation and calculation indicate that, using 2-aminobenzimidazole to end-cap the chains of PAI molecules is beneficial for suppressing the formation of the charge-transfer complexes (CTCs), and thereby offsetting impacts of the reduced molecular chain spacing on the transparency of films. Based on these two influencing factors, we confidently conclude that linear and rigid end-capped groups can effectively improve the dimensional stability and mechanical properties of PAI films without damaging their optical properties.
研究领域:
高分子科学
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材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2023
·
IF 7.4
Xing Gong,Quantao Liu,Xuefei Liu,Pei Wan,Peng Jiang,Shuaichao Chen,Huan Wang,Shaopeng Wu
To increase the storage stability of polyurethane prepolymer (PUP), environmentally friendly end-capped PUP modifier was prepared to modify asphalt, which can improve the performance of bitumen while protecting the environment. Physical, chemical and mechanical characterizations of the end-capped PUP and the modified bitumen were conducted to fundamentally understand its modification mechanism. The outcomes demonstrated that the storage stability of PUP can be significantly increased by end-capping technology. End-capped PUP can be successfully uncapped in bitumen and used to modify bitumen. As a result of the interaction between PUP and the active spots within asphaltene and bituminous resin, urethane, urea, and amide linkages were created, creating a cross-linked structure. The modification procedure encourages the transformation of resin into asphaltene and the reconstruction of asphaltene. With the reorganization of asphaltene molecules and the strengthening of cross-linking, PUP modified bitumen have greatly improved their high temperature resistance. However, as curing time increases, bitumen's chemical composition changes, resulting in decreased low-temperature performance, but it is still better than the base bitumen. This research prepared high storage stability PUP and explored the mechanism of PUP to modify bitumen, which has guiding significance for the usuage of PUP modified bitumen.
研究领域:
材料科学
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化学工程
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2025
·
IF 9
Genyuan Zhang,He Wen,Jing Wang,Ziwen Dai,Yimeng Shi,Hao Tan,Jinghao Dang,Shoujin Wang,Wenbo Yu,Sha Liang,Jiakuan Yang,Shushan Yuan
The development of high-performance nanofiltration membranes for efficient dye/salt separation remains a critical challenge in sustainable wastewater treatment. Herein, we report a tunable strategy to fabricate poly(p-phenylene terephthalamide) (PPTA)-based membranes with tailored pore architectures and surface functionalities. By employing low-temperature polycondensation of terephthaloyl chloride (TPC) and p-phenylenediamine (PPD) in an N-methyl-2-pyrrolidone (NMP) system, followed by selective end-capping, carboxyl- or amine-terminated membranes (PPTA tpc and PPTA ppd ) were synthesized. These membranes exhibited ultrafiltration-level permeance (643.1 and 697.3 L m −2 h −1 bar −1 ) but limited Congo Red (CR) rejection (∼90 %). To refine pore size, trimesoyl chloride (TMC) was utilized to crosslink surface amine groups, generating gradient-pore membranes (PPTA tpc -TMC m and PPTA ppd -TMC m ) with tunable crosslinking degrees. Systematic studies revealed that controlled crosslinking time enabled precise modulation of pore size, facilitating gradient dye rejection while balancing salt permeability. The optimized PPTA tpc -TMC 300s , PPTA ppd -TMC 20s , PPTA ppd -TMC 30s membranes achieved excellent separation factor of 710, 367, and 277 for NaCl/CR, NaCl/Acid Fuchsin (AF), and NaCl/Sunset Yellow (SY) solutions with a pure water permeance of 452.5, 42.5, 28.1 L m −2 h −1 bar −1 , respectively. Long-term stability tests confirmed sustained performance (>99 % dye rejection) due to crosslinking-enhanced structural rigidity. This study establishes a strategic paradigm for fabricating PPTA membranes with programmable pore architectures, elucidating the critical interplay between surface chemistry, tunable pore dimensions, and separation performance.
研究领域:
膜科学
·
高分子化学
·
分离技术
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环境工程
·
材料科学
✓ 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）