POLYMER TESTING
·
2020
·
IF 3.275
Tao Zhou,Hang Xiao,Weifeng Peng,Bo Liang,Yao Liu,Jiangbo Lv,Jianghuai Hu,Ke Zeng,Gang Yang
The pyrolysis behaviors of l -tyrosine-based phthalonitrile(TPN) resin were investigated by thermogravimetric-Fourier transform infrared spectrometry-mass spectrometry (TG-FTIR-MS) and Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The small molecules produced during pyrolysis process of TPN resin were tracked in real time by TG-FTIR-MS. The larger molecules ( m / z > 40) from fast pyrolysis at 900 °C of the TPN resin using Py-GC/MS were identified. From TG-FTIR-MS and Py-GC/MS results, the production pathways of pyrolysis products such as CO 2 , CO, NH 3 , benzonitrile and phenol were analyzed. The possible pyrolysis mechanism of TPN resin under non-oxidizing gaseous environment was proposed. The results of this study provide the useful information for designing the molecular structure of l -tyrosine-based polymers which possessing high thermal stability.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
Polymers
·
2022
·Vol. 14
·期 19
·4127
·
IF 4.967
Xiaobao Li,Zhengjie Tang,Zhenbing Sun,John Simonsen,Zhinan Luo,Xiaoping Li,Jeffery J. Morrell
Carboxymethyl cellulose (CMC) is a cellulose derivative that can be obtained from wood, bamboo, rattan, straw, and other cellulosic materials. CMC can be used to produce biofilms for many purposes, but the properties of these resulting films make them unsuitable for some applications. The effects of three kinds of plant fiber addition on CMC film properties was investigated using CMC derived from eucalyptus bark cellulose. Tensile strength (TS) and elongation at break (EB) of CMC/sodium alginate/glycerol composite films were 26.2 MPa and 7.35%, respectively. Tensile strength of CMC composite films substantially increased, reaching an optimum at 0.50 g of fiber. The enhancement due to industrial hemp hurd fiber on CMC composite films was more obvious. Pretreatment with hydrogen peroxide (H2O2) and glacial acetic acid (CH3COOH) produced films with a TS of 35.9 MPa and an EB of 1.61%. TS values with pectinase pretreated fiber films was 41.3 MPa and EB was 1.76%. TS of films pretreated with pectinase and hemicellulase was 45.2 MPa and EB was 4.18%. Chemical and enzymatic treatment both improved fiber crystallinity, but film tensile strength was improved to a greater extent by enzymatic treatment. Surface roughness and pyrolysis residue of the film increased after fiber addition, but Fourier transform infrared spectroscopy (FTIR), opacity, and water vapor transmission coefficients were largely unchanged. Adding fiber improved tensile strength of CMC/sodium alginate/glycerol composite films and broadened the application range of CMC composite films without adversely affecting film performance.Keywords:eucalyptus bark;Yunnan pine wood;bamboo culms;industrial hemp hurd;FTIR;XRD;TG;mechanical properties
研究领域:
材料科学
·
生物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2019
·
IF 5.589
Shuang Liang,Yueyue Chen,Shiming Zhang,Yuanyuan Cao,Junchao Duan,Yapei Wang,Zhiwei Sun
Silica nanoparticles (SiNPs) have been widely used in human health related products, such as food additives, cosmetics and even drug delivery, gene therapy or bioimaging. Recently, a first-in-human clinical trial based on polyethylene glycol (PEG)-modified SiNPs had been approved by US FDA to trace melanoma. However, as a nano-based drug delivery system, its biocompatibility and vascular toxicity are still largely unknown. Thus, we synthesized the fluorescent SiNPs to explore the biocompatibility and vascular endothelial function, and compare different biological effects caused by PEG-modified and unmodified SiNPs in cells and zebrafish model. The characterizations of SiNPs and PEG-modified SiNPs were analyzed by TEM, SEM, AFM and DLS, which exhibited relatively good stable and dispersive. Compared with SiNPs, PEG-modified SiNPs had markedly reduced the inflammatory response and vascular damage in Tg (fli-1: EGFP) and Tg (mpo: GFP) transgenic zebrafish lines, respectively. Consistent with the in vivo results, the PEG-modified SiNPs had been found to significantly decline the levels of ROS, inflammatory cytokines and mitochondrial-mediated apoptosis in vascular endothelial cells compared to SiNPs, and the ROS scavenger NAC could effectively alleviate the above adverse effects induced by nanoparticles. Our results suggested that the PEG-modified SiNPs could become more safety via increasing the biocompatibility and decreasing cellular toxicities in living organisms.
研究领域:
纳米技术
·
生物医学工程
·
药理学
·
毒理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2025
·
IF 7.4
Haomeng Ma,Hongbin Li,Guangmou Cao,Yang Yu,Xiaolong Wang,Xuedong Lv,Xueshuai Wang,Shufeng Li,Liuchun Zheng
Textiles, as a fast-moving consumer goods (FMCG), are mass produced and used in modern daily life. Polyester-spandex blended fabrics, a major category of pure chemical fiber products, are primarily recycled through the mechanical recycling or chemical degradation, with a notable lack of research on upcycling. We propose a chemical degradation and upcycling pathway based on transesterification principles to prepare high-value transparent poly(ethylene terephthalate)-tricyclodecanedimetthanol (TCDDM) copolymer by discarded polyester-spandex blended fabrics. Employing a selective separation strategy, the spandex component of the polyester-spandex blended fabrics was separated with dimethylacetamide (DMAC) solvent. Then, the separated polyester fabric was chemical degradation with ethylene glycol (EG) solvent to obtain the bis(2-hydroxyethyl) terephthalate (BHET) monomer. The reaction was carried out at 190°C for 3h by setting up a reflux apparatus, This is milder reaction conditions and simpler setup than methanolysis. Finally, the upcycling of r-PETGs containing TCDDM was carried out via melt polycondensation. The r-PETGs possess higher T g of 85.6-115.4°C, and can be utilized in transparent application scenarios under high temperatures. Our work offers a pathway for degrading and upcycling textile waste by transforming it into high-value transparent materials, supporting chemical degradation and circular economy in the fiber industry.
研究领域:
材料科学
·
高分子化学
·
可持续纺织品回收
·
化学工程
·
循环经济
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
·
2015
·Vol. 54
·期 10
·1396-1408
·
IF 3.113
Xiaojuan Zhang,Qian Zhang,Chao Xie,Aiting Gao,Zheng Chang,Jung Kwon Oh,Peng Yang,Pengfei Li
Phosphonated and epoxy-containing norbornene based monomers were prepared by Diels–Alder reaction. They were then combined with three other commercial cyclic unsaturated monomers to synthesize phosphonated homopolymers and copolymers via ring opening metathesis polymerization (ROMP) using second-generation Grubbs catalyst. Glass transitions of these polymers were tunable in a broad range from −14 to 91 °C by varying the flexibility of comonomer. Interestingly, copolymerization with cyclopentene inhibited the crystallization of polycyclopentene, and instead, led to a copolymer with two T g s. Paradoxically, results from thermogravimetric analysis (TGA) were not consistent with the followed flame-retarding experiment, implying that the early weight loss from phosphonated moieties did not deleteriously affect the flame-resistant property which actually depended more on the percentage of char residual after thermal degradation. In application studies, the norbornene derivative phosphonated polymer was tested for the first time as flame retarding material, and showed significant self-extinguishing ability. In a second study, photolithography was also successfully performed via thiol-ene “click” chemistry, which allowed the phosphonated polymer a promising negative photoresist. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54 , 1396-1408
研究领域:
高分子化学
·
材料科学
✓ 已验证
DOI
高影响因子
IRONMAKING & STEELMAKING
·
2026
·
IF 2.1
Jiawen Chen,Liang Yu,Shipeng Xu,Yu Wan
As a crucial functional material in the continuous casting process, mould fluxes play a significant role in ensuring smooth operation and improving the quality of cast billets. To mitigate the environmental impact of fluorides in mould fluxes, TiO2 has been introduced as a network former to reduce viscosity and melting temperature. The formation of perovskite instead of cuspidine also contributes to controlled heat transfer. However, preventing the formation of titanium carbide (TiC) under high-temperature conditions remains challenging. Experimental results indicate that during heating, both CaO–SiO2–TiO2 and CaO–SiO2–CaF2–TiO2 slag systems react to form perovskite. TiO2 participates more readily in solid-state reactions with CaO than CaF2 does, thereby inhibiting the formation of cuspidine. Furthermore, in carbon-containing CaO–SiO2–TiO2 systems, TiC forms along with CO at elevated temperatures. It is revealed that TiC formation does not result from the direct reaction between TiO2 and C, but rather from the reaction between CaTiO3 and C. Under high-temperature carbon-rich conditions, carbon reduces perovskite to form TiC. Consequently, in contrast to fluorine-based fluxes, titanium-bearing mould fluxes require careful optimisation of carbon content to prevent TiC precipitation.
✓ 已验证
DOI
高影响因子
Polymer Chemistry
·
2025
·
IF 3.9
Lang Shuai,Guangwei Xu,Jianglong Li,Jianlong Wen,Boyu Ding,Shui Yu,Yingying Xu,Yijing Nie
To meet environmental challenges and advance sustainable development, it has become imperative to develop engineering glassy polymers with autonomous and room-temperature self-healing capability. Although several strategies for achieving self-healing in glassy polymers have been reported, the underlying mechanism dominating the self-healing process below glass transition temperature (Tg) remains elusive. Herein, we synthesized hyperbranched polyurethanes (HPUs) to leverage their abundant hydroxyl end groups for constructing a dense hydrogen-bonding network. The HPUs exhibit good self-healing ability below Tg (the self-healing efficiency can reach ~50% and ~90% after 0.5 h and 48 h of self-healing, respectively). Both experimental and simulation results revealed that a large number of end groups and branching units in the HPUs undergo secondary relaxation, and can move locally at temperatures below Tg, which is beneficial for the sub-Tg self-healing. In addition, the HPUs containing lower hydrogen bond contents exhibit stronger sub-segment mobility and higher self-healing efficiency, indicating that the mobility of sub-segmental units plays a more important role in promoting the self-healing of glassy hyperbranched polymers rather than the recombination of hydrogen bond content.
研究领域:
高分子科学
·
材料化学
·
自修复材料
·
软物质物理
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Jinghong Liu,Xiaoqing Zhang,Sihui Liu,Caihong Lei
Epoxy resins often age during high-temperature use, causing a drop in T g and a number of safety problems. Currently, no specific reports addressing this T g drop are available. Here, we proposed that the T g drop could be prevented by allyl modification, and designed a series of epoxy monomers containing allyl to demonstrate this view. First, the influence of allyl groups on epoxy monomers was evaluated. It was found that allyl groups could reduce the viscosity of the monomers and the curing rate. These monomers were cured by DDM into resin (virgin resin) and treated at 285 °C for 6 h (treated resin) until the double bond was consumed. By comparison, it was found that although the introduction of allyl groups reduces the T g of the virgin resin, it does not adversely affect the thermal degradation temperature ( T d5% ). The T d5% and T g of the allyl-containing treated resin did not drop significantly like those of the treated resin without allyl. Specially, the T d5% and T g of an allyl-rich resin increased by + 49 and + 289 °C, respectively. According to further study of the network generated by allyl groups, the allyl group in the para position (relative to the glycidyl ether group) would produce greater cross-linking, whereas the intramolecular ring formation in the ortho position results in an imperfect network of the new resin. Finally, through qualitative analysis of the entire resin network, we believe that this is a result of the high-temperature destruction of the epoxy network and the formation of an allylic network.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2017
·
IF 3.684
Lala Rukh Sidra,Guofei Chen,Nafeesa Mushtaq,Lubo Xu,Xiaoqi Chen,Yantao Li,Xingzhong Fang
To extend the upper operating temperature range of melt processable PIs , two series of end-capped copolyimides based on hydroquinone diphthalic anhydride (HQDPA) isomers were designed by varying the contents of appropriate diamines. Thus, copolyimides PI-(0a∼20a) based on 3,3′-HQDPA were prepared by varying the ratio of rigid 2-(4-aminophenyl)-5-aminobenzimidazole (BIA) and flexible 4,4′-oxydianiline (ODA). The resulting copolyimides demonstrated good properties, such as excellent solubility, high T g ranging from 328 to 354 °C as determined by dynamic mechanical analyzer (DMA), besides, exhibited good thermal stability based on 5% weight loss temperature ( T 5% ) of 502–514 °C and low melt viscosity in the range of 291–935 Pa·s. Most importantly, PI-20a showed a good combination of low melt viscosity simultaneously with significantly high T g (328 °C). Furthermore, this system was modified by copolymerization with different feed ratio of 4,4′-HQDPA isomer and produced another series PI-(20a∼20e), that exhibited high T g in the range of 315–330 °C with T 5% of 502–543 °C and minimum complex viscosity in the range of 291–479 Pa·s. All PIs form tough and flexible films that have remarkable tensile strength and moduli in the range of 93–116 MPa and 3.7–4.7 GPa, respectively.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES SCIENCE AND TECHNOLOGY
·
2023
·
IF 9.1
Xiaofei Wang,Yang He,Xinli Xiao,Jinsong Leng
Shape memory polyimide (SMPI) is one of the most promising intelligent materials and has a high potential for deformable flexible electrodes , intelligent thermal management devices, and high temperature active deployable structures , etc. In this paper, silane-modified AlN nanoparticles (M-AlN) are composited with SMPI matrix resin to prepare fast-response high-T g shape memory composites. Besides, nano-sized AlN and micron-sized Al 2 O 3 are used to construct “micro-nano” synergistic thermal conduction networks, in which the AlN acted as the “thermal conduction island”, and the Al 2 O 3 acted as the “thermal conduction bridge”. The results show that the in-plane thermal conductivity of Al 2 O 3 /M-AlN/M-SMPI-2 is 5.99 W m −1 K −1 , compared with SMPI, its thermal conductivity increases by 91%. In addition, the shape transition temperature of Al 2 O 3 /M-AlN/M-SMPI-2 was higher than that of pure SMPI, which was at 426 °C, and the thermal response shape recovery speed is also greatly improved by 433%, which can be used in rapid-actuating and high temperature active deformation structure .
研究领域:
材料科学
·
智能材料
✓ 已验证
产品关联
DOI
高影响因子
Polymer Chemistry
·
2023
·Vol. 14
·期 32
·3718-3728
·
IF 4.6
Chaojie Li,Jiannan Cheng,Yi Zhang,Qing Yu,Zhiru Yuan,Weiwei He,Xiaoguang Bao,Lifen Zhang,Zhenping Cheng
Fluorinated polymers are a class of fascinating materials due to their unique features; however, they have not been applied widely in daily life because of the restricted synthetic methodology and limited availability of various monomers. In this work, main-chain-type semifluorinated alternating terpolymers (SFATs) (AB1)n-co-(AB2)m are prepared by a step transfer-addition and radical-termination (START) polymerization strategy using NaI as the catalyst under irradiation with visible light at room temperature. Herein, 1,6-diiodoperfluorohexane and two α,ω-unconjugated dienes with different structures are used as A, B1 and B2 monomers, respectively. Interestingly, a dual alternating polymerization process can be possible at the beginning of terpolymerization by using dienes with flexible and rigid chains as B1 and B2, respectively. In addition, compared to binary copolymers (AB)n previously synthesized by START polymerization, facile regulation of Tg of the SFATs can be achieved easily either by adjusting the feed ratio of two B monomers or by the removal of the periodic iodine atoms formed in SFATs. Overall, this work provides a guide for the synthesis of a broad range of fluorinated polymers by increasing participating monomers, allowing easier adjustment of the chemical composition and facilitating the integration of desirable properties into fluoropolymers to fulfill diverse requirements in practical application.
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
EUROPEAN POLYMER JOURNAL
·
2024
·
IF 5.8
Xingwang Lai,Shan Huang,Jialin Zhang,Xialei Lv,Fangfang Niu,Jinhui Li
Photosensitive Solder resist (SR) materials require a high glass transition temperature ( T g > 170 °C) and a coefficient of thermal expansion matching that of copper (CTE≈17 ppm/°C) to meet the demands of manufacturing processes and application reliability. However, the commonly used epoxy resin in SR materials exhibits insufficient mechanical and thermal properties, failing to meet these requirements adequately. To address this issue, alkali-soluble photosensitive poly (amic ester) (PAE) materials were synthesized. By grafting a low-temperature curing accelerator, 6-([1,1′-biphenyl]–4-yl)–4-chloroquinoline (NQL), onto the hydroxyl groups of the PAE, the resultant grafted PAE resin was blended with an alkali-soluble photosensitive modified epoxy resin (APE) to enhance the mechanical and thermal properties of the SR composite. Research indicates that due to the low-temperature curing effect and electrostatic interactions of NQL, SR-2 (with a 10% PAE addition) exhibits a T g of 183 °C and a CTE of 16 ppm/°C, while SR-3 (with a 30% PAE addition) achieves a T g of 204 °C and a CTE of 20 ppm/°C. Furthermore, with the PAE addition of 5%, the lithography quality of SR is enhanced, enabling SR-1 to achieve a pattern resolution of up to 40 μm. The modification method involving PSPI blending has been shown to enhance the thermal stability, dimensional stability, and lithographic performance of SR, indicating significant potential applications in solder resist materials.
研究领域:
材料科学
·
电子工程
✓ 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）