POLYMERS FOR ADVANCED TECHNOLOGIES
·
2025
·Vol. 36
·期 9
·e70304
·
IF 3.4
Yong Liu,Jiaming Guo,Zongwei Guo,Lei Shang,Yuhui Ao
The thermal oxidation stabilization process of polyacrylonitrile (PAN) is a violent exothermic reaction process, which is not conducive to the improvement of carbon fiber quality. The highly exothermic reaction was often alleviated by adding unsaturated vinyl carboxylic acid monomers. In this investigation, poly(acrylonitrile-co-2-carboxyethyl acrylate) P(AN-co-CEA) copolymers with varying contents of CEA monomers were synthesized. The effects of CEA on the thermal behavior and structural evolution of copolymers were systematically investigated by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and thermal gravimetric analyzer (TGA). The results indicated that the introduction of CEA facilitated the cyclization reaction at lower temperatures through the ionic mechanism of the carboxyl group, broadened the exothermic peak, and reduced the heat release rate (Δ H /Δ T ). The activation energies (E a ) decreased from 157.7 KJ/mol for PAN homopolymer to 122.3 KJ/mol for P(AN-co-CEA) copolymer. Moreover, the CEA monomer promoted both the cyclization and dehydrogenation reactions, forming more stable cyclic structures and inhibiting the thermal decomposition of random chain segments. Consequently, higher carbon yield and a greater extent of stabilization (Es) were achieved. Additionally, the combined action of CEA and O 2 jointly enhanced the thermal oxidation stability process, resulting in the formation of oxygen-containing structures and promoting the transition to a graphite-like carbon network. Among the copolymers studied, the composition containing 2 wt% CEA exhibited the most favorable balance in the development of a well-stabilized structure. It was found that the CEA comonomer has the ability to promote the thermal oxidation stabilization process, alleviate the highly exothermic reactions, and reduce the heat release rate. Hence, these findings suggest that P(AN-co-CEA) copolymers have the potential to become carbon fiber precursor materials.
研究领域:
高分子化学
·
材料科学
·
碳材料
·
纤维工程
·
热分析
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2014
·Vol. 5
·期 6
·4162-4170
·
IF 3.708
Xinfeng Cheng,Yong Jin,Tongbing Sun,Rui Qi,Baozhu Fan,Hanping Li
A novel diselenide crosslinked poly(N-isopropylacrylamide-co-2-hydroxyethyl acrylate) hydrogel was successfully synthesized and characterized. The resultant hydrogel showed a swelling–shrinkage behavior as a function of external temperature because of the unique hydrophilic–hydrophobic transition of poly(N-isopropylacrylamide) (PNIPAM) segments. In addition to the temperature-dependent response, the oxidation-induced gel-to-sol transition of the hydrogel was also observed. The salicylic acid (SA) loaded hydrogels were prepared in order to investigate their stimuli-responsive release behaviors. The cumulative release profile of the SA-loaded hydrogels showed a thermo-induced slow sustained drug release and an oxidation-induced quick burst release, exhibiting temperature/oxidation dual-stimuli-responsive drug release. This novel type of hydrogels may hold great promise for controlled drug delivery systems.
研究领域:
材料科学
·
生物医学工程
·
药学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THERMOPLASTIC COMPOSITE MATERIALS
·
2022
·
IF 3.027
Yinan Sun,Xiangchi Liu,Tingting Liu,Baijun Liu,Mingyao Zhang
Polyacrylate latexes with uniform particle size and excellent dispersion were successfully synthesized via emulsion copolymerization of butyl acrylate and 2-ethylhexyl acrylate with different types of grafting agents. The effect of grafting agent type for residual double bonds of seed latex was discussed. The results indicated that the residue double bonds of acrylic seed latex of graft agents with non-equally active double bonds were higher than acrylic seed latex of graft agents with equally active double bonds. Acrylic impact modifiers (ACR) were generated by using an emulsion grafting polymerization of polyacrylate latex as the core and poly (methyl methacrylate) (PMMA) as the shell for preparing poly(vinyl chlorid) (PVC)/ACR blends. Mechanical properties test analysis shows that the PVC/ACR blend reached a brittle-toughness transition when the ACR content was 8 phr, indicating that modifiers play a good toughening role in the matrix. The highest impact strength of PVC toughened through ACR (dicyclopentenyl acrylate as grafting agent) was 1682 J/m, almost 62 times than the pure PVC, whereas only 45 times than the pure PVC that of traditional ACR prepared PVC/ACR blend. Scanning electron microscope graphs showed that the shear yielding of the matrix was the major toughening mechanisms.
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
CARBOHYDRATE POLYMERS
·
2014
·
IF 3.916
Xinyu Hu,Liandong Feng,Wei Wei,Aming Xie,Shiming Wang,Jianfa Zhang,Wei Dong
Salecan is a novel water-soluble, high molecular mass extracellular β-glucan produced by Agrobacterium sp. ZX09. Salecan has excellent physicochemical and biological properties, making it very suitable for hydrogel preparation. In this study, a series of novel semi-interpenetrating polymer network (semi-IPN) hydrogels containing Salecan and poly(N,N-dimethylacrylamide-co-2-hydroxyethylmethacrylate) (poly(DMAA-co-HEMA)) were synthesized by radical polymerization and semi-IPN technology. Structure and morphology of the hydrogels were characterized by FTIR, XRD, TGA and SEM. The semi-IPNs had a well-interconnected porous structure with tunable pore size ranging from 6 to 41 μm. Swelling capability of the hydrogels was improved by introducing the hydrophilic Salecan. Rheological results indicated that the incorporation of poly(DMAA-co-HEMA) into hydrogels enhanced the storage modulus. Compression tests revealed that these semi-IPNs were robust materials with compressive modulus between 13.3 and 90.5 kPa, the addition of Salecan increased the fracture strain from 71.1% to 88.8%. Degradation and cytotoxicity tests demonstrated that semi-IPNs were degradable and non-toxic.
研究领域:
材料科学
·
高分子化学
·
生物医学工程
·
生物技术
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2022
·Vol. 33
·期 8
·5750-5762
·
IF 2.779
Ling Chen,Yimin Dai,Qi Lu,Chengqian Fang,Zhiheng Wang,Yaqi Li,Ling Cai,Bo Liu,Yue-fei Zhang,Yan Li,Li Wan
A new environmental-friendly magnetic cellulosic adsorbent MnFe 2 O 4 @Cel-g-p(AA-DMC) was easily synthesized via natural cellulose and easy-recovered magnetic particles MnFe 2 O 4 . Magnetic cellulose composites were characterized by SEM, TEM, XPS, XRD, BET, VSM, TGA and FTIR. The effect of pH, contact time and PMS dosage on adsorption was investigated. Besides, the adsorption kinetic model was well-fitted to the pseudo-second-order model, and the adsorption isotherm were matched with the Frenudlich isotherm model. The MnFe 2 O 4 @Cel-g-p(AA-DMC) posseses the excellent stability, reusability and superior superparamagnetic behavior and its possible adsorption mechanism for the adsorption of CR was proposed.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
Nature Communications
·
2024
·Vol. 15
·期 1
·1-15
·
IF 14.7
Liang Jie,Li Jun,Dong Hongliang,Li Zixiaozi,He Xun,Wang Yan,Yao Yongchao,Ren Yuchun,Sun Shengjun,Luo Yongsong,Zheng Dongdong,Li Jiong,Liu Qian,Luo Fengming,Wu Tongwei,Chen Guang,Sun Xuping,Tang Bo
It is vital to explore effective ways for prolonging electrode lifespans under harsh electrolysis conditions, such as high current densities, acid environment, and impure water source. Here we report alternating electrolysis approaches that realize promptly and regularly repair/maintenance and concurrent bubble evolution. Electrode lifespans are improved by co-action of Fe group elemental ions and alkali metal cations, especially a unique Co 2+ -Na + combo. A commercial Ni foam sustains ampere-level current densities alternatingly during continuous electrolysis for 93.8 h in an acidic solution, whereas such a Ni foam is completely dissolved in ~2 h for conventional electrolysis conditions. The work not only explores an alternating electrolysis-based system, alkali metal cation-based catalytic systems, and alkali metal cation-based electrodeposition techniques, and beyond, but demonstrates the possibility of prolonged electrolysis by repeated deposition-dissolution processes. With enough adjustable experimental variables, the upper improvement limit in the electrode lifespan would be high.
研究领域:
电化学
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Weiqian Song,Yangxi Yan,Maolin Zhang,Dongyan Zhang,Li Jin,Zhimin Li
In this study, Co-doped 0.49 Pb(Ni 1/3 Nb 2/3 )O 3 -0.51 Pb(Hf 0.3 Ti 0.7 )O 3 ceramics with high piezoelectric constants, electromechanical coupling coefficients, and low dielectric losses were prepared by conventional solid-phase reaction method for use as piezoelectric energy harvesters in both resonant and non-resonant working states. XRD results showed the dissolution of Co ions in the crystal lattice , thereby replacing B-sites and transforming the crystal phase into tetragonal phase. Valence states of Co obtained from fitted XPS data confirmed the existence of Co as Co 2+ in the lattice. The introduction of Co 2+ effectively increased grain size, improved ferroelectric properties , reduced leakage current density, and enhanced electromechanical coupling coefficient k p . Impacts of Co-doping on properties of the as-obtained ceramics were discussed. The optimal performances were obtained at x = 1.25, with piezoelectric constant d 33 ~780 pC/N, electromechanical coupling coefficient k p ~0.62, and dielectric loss tan δ = 0.78%. In sum, the excellent piezoelectric properties of Co-doped PNN-PHT ceramics look promising for use as piezoelectric energy harvesters.
研究领域:
材料科学
·
陶瓷
·
压电材料
·
能量收集
✓ 已验证
DOI
高影响因子
Polymer Chemistry
·
2016
·Vol. 8
·期 5
·865-878
·
IF 5.687
Gehong Su,Tao Zhou,Xifei Liu,Yanan Ma
In this study, the micro-dynamics mechanism of the volume phase transition behavior of the poly(N-isopropylacrylamide-co-2-hydroxyethyl methacrylate) (PNIPAM-co-HEMA) hydrogel was investigated by temperature-dependent FTIR spectroscopy in combination with the perturbation correlation moving window (PCMW2D) technique and generalized two-dimensional correlation analysis. In conventional 1D FTIR spectra analysis, Boltzmann fitting curves showed that the volume phase transition temperature and the phase transition degree of the PNIPAM-co-HEMA hydrogel were lower than those of the pure PNIPAM hydrogel. They also showed that the PHEMA segments exhibit a similar “phase transition” behavior to the PNIPAM segments, which can be ascribed to the driving effect of the phase transition of PNIPAM segments. Furthermore, we found that the rate at which water molecules were expelled out of the gel structure during phase transition changed in an anti-S shape. PCMW2D spectra revealed that the phase transition can be divided into two processes (named I and II) upon heating, and further determined the temperature regions of processes I and II to be 21.8–31.4 °C and 31.4–36.5 °C, respectively. Finally, generalized 2D correlation analysis found that both processes I and II can be further divided into nine steps. From the deduced nine steps of process I, the significant role of PHEMA in the phase transition of PNIPAM segments was revealed. As for the deduced nine steps of process II, the driving effect of the phase transition of PNIPAM segments for PHEMA segments was confirmed.
研究领域:
材料科学
·
生物医学工程
·
高分子化学
✓ 已验证
DOI
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2016
·
IF 4.758
Xiangping Wen,Lihong Shi,Guangming Wen,Yanyan Li,Chuan Dong,Jun Yang,Shaomin Shuang
We report a facile and eco-friendly strategy for the fabrication of highly fluorescent nitrogen-doped carbon nanodots (N-CDs) and demonstrate their applications for multicolor cellular imaging and Co 2+ sensing in living cells. One-pot hydrothermal method using pigskin as the precursor yields bright green-emitting N-CDs, providing an easy way for the production of N-CDs without a tedious synthetic methodology or the toxic/expensive solvents and starting materials. Doping N heteroatoms benefits the generation of N-CDs with stronger fluorescence emission. As-prepared N-CDs exhibit exceptional advantages including high fluorescent quantum yield (24.1%), excellent biocompatibility, low-toxicity, and satisfactory chemical stability. Depending on these superior properties, as-synthesized N-CDs have been successfully used for multicolor cellular imaging. More strikingly, as-synthesized N-CDs generates strong response to Co 2+ ions and gives rise to the fluorescence quenching and further application is extended to precise and quantitative detection of Co 2+ ions in living cells.
研究领域:
材料科学
·
纳米技术
·
生物医学工程
·
分析化学
·
细胞生物学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Zhige Zhang,Guican Bi,Shenglong Zhang,Tao Tan,Jun Xie
The use of biogas as renewable raw material to produce syngas（H 2 /CO ≈ 2）suitable for direct synthesis of methanol has attracted wide attention, but designing promising catalysts with high activity and stability remains a challenge. The catalytic systems used for this process usually have the characteristics of poor stability and easy carbon deposition. Here, Based on the Ce redox cycle and the strong metal-support interaction (SMSI), we designed and synthesized a series of Ni catalysts (denoted as Ni/CeMgO x /BN) with BN interfacial constraints. The abundant oxygen vacancy of reaction-induced Ce redox cycle endows Ni/CeMgO x /BN with excellent carbon resistance, because the ability to activate CO 2 /H 2 O is significantly enhanced. The CO 2 /H 2 O activation and carbon elimination mechanism were comprehensively characterized by in situ H 2 -TPR/CO 2 /H 2 O-TPSR, in situ CH 4 -TPSR/CO 2 /H 2 O-TPO, and FTIR, etc. Ascribed to the appropriate basicity of CeMgO x , homogeneous Ni dispersion, and strong interaction between Ni ultra-small nano particles (NPs) and CeMgO x /BN, Ni/CeMgO x /BN exhibit higher CO 2 /H 2 O adsorption/activation, higher CH 4 activation/dissociation, compared with another samples, which facilitate the formation of active oxygen species and intermediate coke removal, thus enhance the resistance to coke deposition and sintering. At 750 °C, Ni/CeMgO x /BN exhibit satisfying catalytic activity (CH 4 /CO 2 conversation 92 %/52 %) and superior stability (100 h) with negligible deactivation rates.
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
RSC Advances
·
2015
·Vol. 5
·期 26
·20227-20233
·
IF 3.84
Chuntao Liu,Xin Liu,Changyun Quan,Xiaoqiong Li,Chaozhu Chen,Hua Kang,Weikang Hu,Qing Jiang,Chao Zhang
Methacrylated poly(γ-glutamic acid) (mPGA) was introduced to the spongy poly(ethylene glycol)-co-2-hydroxyethyl methacrylate (PEG-HEMA) cryogels. A suitable amount (<0.1% w/v) of poly(γ-glutamic acid) (γ-PGA) in cryogels was found to promote homogeneous mineralization, while higher concentration of γ-PGA inhibited the mineralization. The deposited minerals mainly consisted of hydroxyapatite, carbonated apatite, and calcium phosphate, and were independent on the concentration of γ-PGA. The mineralized cryogels can support adhesion, viability, and migration of rat bone marrow stromal cells (rMSCs). The γ-PGA/HEMA-PEGDA cryogels showed their great potential as promising scaffolding materials in bone tissue engineering.
研究领域:
生物材料学
·
组织工程学
✓ 已验证
产品关联
DOI
高影响因子
KOREAN JOURNAL OF CHEMICAL ENGINEERING
·
2020
·Vol. 37
·期 4
·614-622
·
IF 2.69
Haleem Abdul,Syaal Sidra Bibi,Ajmal Muhammad,Ambreen Jaweria,Rauf Sajid,Ali Nasir,Muhammad Saz,Shah Afzal,Zia Muhammad Abid,Siddiq Muhammad
Here in, we demonstrate facile fabrication of silver and palladium nanoparticles in dual responsive poly(N-isopropylacrylamide- co -2-Acrylamido-2-methylpropane sulfonic acid) microgel with temperature- and pH-dependent catalytic potential. Palladium-based catalyst showed better catalytic efficiency as compared to silver-based catalyst for degradation of Rhodamine-B and P-Nitrophenol in aqueous medium under the same set of reaction conditions. The responsive nature of the microgel was found to be useful to tune the catalytic activity of the as-prepared catalysts, and reduction rate was enhanced with the pH and temperature elevation of the reaction medium; however, the increasing trend was slowed in the volume phase transition region of the microgel. Under a specific set of reaction conditions, the reduction of Rhodamine-B was as fast as 0.968 and 0.571 min −1 when catalyzed with palladium and silver based catalysts, respectively. The hydrodynamic radius of the particles of microgel support was found to be in the range of 65-180 nm when pH and temperature of the medium were varied in the range of 2-12 and 25-45, respectively. The estimated diameter of silver and palladium nanoparticles fabricated in the microgel support under the same set of reaction conditions was 9-15 and 7-11 nm, respectively.
研究领域:
材料科学
·
化学工程
·
纳米技术
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）