RSC Advances
·
2021
·Vol. 11
·期 41
·25158-25169
·
IF 3.361
Zheng Wang,Mei-chen Liu,Zhi-yuan Chang,Hui-bo Li
In this research, the graft modification mechanism of coupling agent vinyl triethoxysilane (KH-151) to macroporous silica gel was studied using a combination of multiple methods. SEM, FTIR, RAMAN, NMR and XPS were used to characterize the silica gel before and after grafting, determining the mechanism of the grafting reaction of the silane coupling agent. On this basis, the grafting rate of the coupling agent was accurately calculated by TGA weight loss. From the results of characterization, it can be seen that the coupling agent molecules have two connection types on the surface of silica gel, and the ratio of the two types is 43.51% and 56.49% respectively. The influences of hydration degree of the silica gel, coupling agent dosage and reaction temperature on the grafting rate were explored, and the optimal reaction conditions for the modification of macroporous silica gel were determined by the coupling agent through orthogonal experiments, that is, the hydration degree of silica gel of 10%, a coupling agent dosage of 12 mL, and a reaction temperature of 80 °C. Under optimal reaction conditions, the average grafting rate of the coupling agent vinyl triethoxysilane (KH-151) on macroporous silica gel is as high as 91.03%.
研究领域:
材料科学
·
化学工程
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PubMed
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2020
·
IF 3.408
Huimin Guo,Chao Li,Hongxin Hu,Xiaoyan Yu,Kimiyoshi Naito,Qingxin Zhang
Nanodiamonds are novel carbon nanoparticles , which have wide application prospect around various fields owing to the excellent properties. However, nanodiamonds exhibit great tendency to aggregate and this phenomenon extremely limits the application of nanodiamonds. Two simple and green approaches of “grafting from” and “grafting to” are conducted to modify nanodiamonds covalently with copolymer of poly(ϵ-caprolactone) and polyethylene glycol . The characterizations of FT-IR, Raman spectra and TGA indicate that the copolymers are covalently linked on nanodiamonds surface through “grafting from” and “grafting to” methods successfully and the grafting rates are 13.35% and 20.87%, respectively. Moreover, the modified nanodiamonds present smaller particle diameter, less aggregation and better dispersion in organic solvent according to the dynamic light scattering particle size analyzer, transmission electron microscopic analysis and natural sedimentation experiment, which may have potential application at many fields.
研究领域:
材料科学
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化学工程
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高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2022
·
IF 8.025
Jingna Liu,Liu Cui,Yuying Shi,Qiong Zhang,Yuangong Zhuang,Peng Fei
In this study, docosanoic acid, a very long chain fatty acid , was used to modify pectin, and the products were incorporated with carboxylmethyl cellulose (CMC) to prepare a hydrophobic composite. Results of structural characterisation showed that docosanoic acid was grafted to pectin through the esterification reaction, and the highest grafting ratio was 7.89 %. After grafting with docosanoic acid, the emulsifying activity and stability of pectin were significantly enhanced from 1.23 × 10 −2 and 9.27 % to 4.78 × 10 −2 and 26.73 %. Moreover, when modified pectin was blended with CMC instead of native pectin, the hydrophobicity of the composite membranes increased significantly. In detail, the highest contact angle of the composite membrane incorporated with modified pectin was 97.6°, which was much higher than that with native pectin (68.9°). As the grafting ratio of pectin increased, the water vapor permeability of the composite membranes significantly increased, while the water absorption decreased. Furthermore, the mechanical properties and transparency of the composite membranes could be improved by grafting docosanoic acid into pectin. All the results indicated that incorporating docosanoic acid possibly helped improve the comprehensive properties of the composite membranes based on polysaccharides and expand their application in food packaging.
研究领域:
食品科学
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材料科学
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PubMed
高影响因子
ACS Applied Polymer Materials
·
2020
·
IF 0
Di Sha,Xu Yang,Baolong Wang,Xue Liu,Chunxia Li,Yongkang Tang,Min Wei,Zhiwei Liang,Hua Wei,Jiuduo Xu,Kai Shi,Xiangling Ji
A quaternary ammonium salt (QA), epoxypropyl-N,N-dimethyldodecylammonium chloride (EDAC), is grafted on macroporous polyvinyl alcohol-formaldehyde (PVF) sponges via facile reaction conditions. The grafting percentage (GP) of QA is influenced by the reaction temperature, time, and catalyst concentration, and the optimal GP can reach up to 43.3%. As-prepared PVF-g-QA sponges show average pore size in the range of 60–90 μm and high porosity above 80%. Meanwhile, the resultant PVF-g-QA samples also display a high water absorption capacity approximately 12.4–14.2 g/g and reach dynamic absorption equilibrium quickly within only 1 min in both saline solution and deionized water. Notably, the antibacterial performance of these sponges for both E. coli and S. aureus are excellent with a reduction of four orders of magnitude compared with a high initial concentration of bacteria (108 CFU/mL). Moreover, the as-prepared samples with different grafting percentages almost have no cytotoxicity for cells. The PVF-g-QA sponges can serve as a candidate for wound dressings for medical and sanitary applications.
研究领域:
材料科学
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生物学
·
医学
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DOI
Journal of Energy Storage
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2020
·
IF 3.762
Yi Wang,Ziyi Qin,Ting Zhang,Deyi Zhang
Aiming to reveal the relationship between the thermophysical properties of shape-stabled phase change materials (PCMs) with the structure of its matrix, a series of stearic acid/three-dimensional attapulgite (SA/TATP) composite PCMs were fabricated by vacuum impregnation method using TATP as matrix, which prepared via “grafting from” method and employed attapulgite (ATP) as raw material, diphenylmethane diisocyanate (MDI) as modifying agent and amines as linking molecules. The structure of carriers, thermophysical properties of the composite PCMs were analyzed, and the relationship between the thermophysical properties of SA/TATP and characteristics of the carrier were also studied. The results indicated that the thermophysical properties of the composite PCMs were improved significantly due to the introduce of organic bonding agents and the formation of three-dimensional network in the matrix. The latent heat of SA/TATP can be up to 136.81 J/g without leakage, and the maximum thermal conductivity of SA/TATP is 0.4215 W/m•K. The melting temperature and melting latent heat of the composite PCMs degenerate with the decrease of the pore size of the carriers. The relationship between the melting phase transition temperature, melting latent heat of SA/TATP and pore size of TATP can be descripted by the Gibbs–Thomson equation. In addition, the melting enthalpy of SA/TATP is positively associated with the grafting rate of the carrier.
研究领域:
材料科学
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热能工程
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高影响因子
Polymers
·
2022
·Vol. 15
·期 1
·143
·
IF 4.967
Shiyou Zhao,Jin Li,Lifeng Wu,Ming Hua,Changmei Jiang,Ying Pan,Lirong Yao,Sijun Xu,Jianlong Ge,Gangwei Pan
Cellulose diacetate (CDA) and L-lactide (L-LA) were used to prepare CDA−g−PLLA with a low glass transition temperature under different process conditions. Given the high glass transition temperature (Tg) of CDA, the thermal processing performance of CDA is poor, which greatly limits its application fields. To decrease the Tgof CDA, graft copolymerization was used in this research. A CDA−g−PLLA graft copolymer was synthesized by grafting CDA with L-LA under different reaction conditions using stannous octanoate as the catalyst and variations in the grafting rate under different reaction conditions were compared. The chemical structure and crystal structure of the CDA−g−PLLA were investigated, and thermal properties were also studied. The results showed that the grafting rate was the highest at the L-LA/CDA mass ratio of 4:1 under a reaction temperature of 150 °C for 90 min, and no poly-L-lactide (PLLA) homopolymer was found among the CDA−g−PLLA graft copolymers after purification. The Tgof CDA−g−PLLA was 54.2 °C, and the initial temperature of weightlessness of CDA−g−PLLA was 218.7 °C. The regularity of the original CDA molecular chains was destroyed after grafting PLLA molecular chains. In this research, we investigated the optimal grafting conditions for CDA−g−PLLA and the CDA−g−PLLA had a low Tg, which improves the thermal processing performance of CDA and broadens its application prospects in the industry.Keywords:cellulose diacetate;grafting rate;process condition;polylactide;thermal processing temperature
研究领域:
材料科学
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化学工程
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PubMed
高影响因子
JOURNAL OF POLYMER RESEARCH
·
2017
·Vol. 24
·期 5
·1-9
·
IF 1.615
Xue Sheng,Yang Haicun,Ma Wenzhong,Gong Fanghong,Tao Guoliang,Liu Chunlin,Pan Ji
Poly(methyl methacrylate) brushes grafted from attapulgite nanoparticles (ATP@PMMA) were prepared by R-Supported reversible addition-fragmentation chain transfer polymerization (RAFT). ATP was firstly activated, and allowed to react with γ-aminopropyltriethoxysilane (APTES), 4,4′-azobis(4-cyanovaleric acid) (ACVA) and bis(thiobenzoyl) disulfide stepwise to afford 4-cyanopentanoic acid dithiobenzoate functionalized ATP (ATP-CPADB). Then, RAFT polymerizations of MMA mediated by the different systems were conducted and compared systemically. The grafting process was verified by FTIR, XRD, XPS, TGA and TEM data. Kinetic behavior indicated that the anchored CPADB is more effective before diffusing into the bulk phase. The grafting ratio ( G
r ), while M
n of grafted and free polymer increased linearly with increasing monomer conversion in presence of free CPADB, giving the hybrid particles with more homogeneous distribution of grafted polymer layer.
研究领域:
材料科学
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高分子化学
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DOI
高影响因子
HIGH ENERGY CHEMISTRY
·
2023
·Vol. 57
·期 1
·28-34
·
IF 0.7
Fan K.,Zhou G. Q.,Gao C. Y.,Li J. H.,Xu F. L.
Abstract This paper reports on the study that gamma-ray irradiation-induced polymerization of N-isopropyl acrylamide (NIPA) to form Poly(N-isopropyl acrylamide) (PNIPA), which was then grafted on the surface of polyvinylidene fluoride (PVDF) membrane to prepare modified PVDF-g-PNIPA membrane. We analyzed the influence of different irradiation doses and dose rates on the grafting rate of modified membranes, and the grafting rate increased with the irradiation dose under a certain irradiation dose. Through analysis of Fourier transform infrared spectroscopy (FTIR) and thermogravimetry (TGA), the efficient progress of the grafting reaction was confirmed. With the increase of the grafting rate, the pore size of the membrane surface decreased gradually, but the surface roughness of the membrane tended to increase through the analyse of scanning electron microscopy (SEM) and atomic force microscopy (AFM). Finally, a mechanistic explanation for the grafting of PNIPA on the surface of PVDF membranes based on these experimental results was proposed.
研究领域:
材料科学
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高分子化学
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高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2014
·Vol. 131
·期 23
·
IF 1.64
Nenmei Jian,Tao Xu
In this article, we report that thermoresponsive poly( N -isopropyl acrylamide) (PNIPAAm) was successfully grafted onto a cotton fabric (CF) surface by free-radical solution grafting polymerization; we obtained a thermoresponsive CF-grafted PNIPAAm. This reaction system only contained four constituents: the monomer, solvent, initiator, and CFs. Ammonium peroxydisulfate was chosen as the initiator, and water was chosen as the solvent. A series of initiator concentrations and grafting polymerization temperatures were used in the experiments, and their effects on the grafting ratio ( G ) were also studied. Also, the effects of the G of CF- g -PNIPAAm on their corresponding thermoresponses was studied further. The structure of CF- g -PNIPAAm was characterized by Fourier transform infrared spectroscopy–attenuated total reflectance analysis and scanning electron microscopy analysis. The G of CF- g -PNIPAAm was measured by a gravimetric method. The thermoresponse of CF- g -PNIPAAm was characterized by modulated differential scanning calorimetry, water contact angle measurements, and wetting time measurements. The experiments manifested the following results: (1) the initiator concentration and grafting polymerization temperature both influenced G, (2) the grafted PNIPAAm covered the CF surface, (3) the CF- g -PNIPAAm showed thermoresponsive hydrophilicity/hydrophobicity, and (4) a relationship existed between the thermoresponse of CF- g -PNIPAAm and the corresponding G . © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131 , 41193.
研究领域:
材料科学
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高分子化学
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纺织工程
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高影响因子
FIBERS AND POLYMERS
·
2017
·Vol. 18
·期 5
·891-899
·
IF 1.113
Wang Yixi,Zhang Chongyang,Zhao Linyan,Meng Guihua,Wu Jianning,Liu Zhiyong
A novel cellulose-based porous adsorbent with high adsorption capacity for methylene blue (MB) was prepared by free radical polymerization methods. The obtained polymer grafting rate and dye removal efficiency are as high as 338.64 % and 97.74 %, respectively, when the dosage of monomer is 4.5 g, the polymerization condition is 3 h at 70 °C. The cellulose-based adsorbent showed high mechanical properties and good flexibility. The Langmuir isotherm model revealed that the maximum theoretical adsorption capacity of this material for methylene blue was 1734.816 mg g-1 at pH 9.0 at 313 K, which is higher than the values observed for other adsorbents. Scanning electron microscopy (SEM) showed that the cellulose-based adsorbent exhibits a typical well-defined porous and interconnected three-dimensional framework structure, which is benefits to dye adsorption. The adsorption kinetics (pseudo first-order, pseudo-second-order, and intraparticle diffusion models) was also studied, and the pseudo-second-order model fitted MB adsorption better than the pseudo-first-order and intraparticle diffusion models at different initial dye concentrations (500-3000 mg l
-1 ). The novel polyacrylic acid-grafted quaternized cellulose (PAA- g -QC) adsorbent is thus potentially useful for the treatment of dye-contaminated wastewater.
研究领域:
环境科学
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材料科学
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高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2022
·
IF 8.025
Jinying Pang,Qifeng Gao,Lili Yin,Shuhua Zhang
In this study, banana cellulose nanofibres (BNCFs) were prepared using waste banana stems. A novel two-dimensional (2D) Zn-MOF was synthesized using 5-(1-hydro-imidazolyl) isophthalic acid as the ligand. The results of the X-ray diffraction, thermogravimetry , and scanning electron microscopy analyses confirmed the stability of Zn-MOF. Thus, Zn-MOF was used to catalyze BNCFs grafted with poly(ε-caprolactone) (ε-CL) (BGCL) by homogeneous ring-opening polymerization in ionic liquid . The grafting ratio of the BGCL prepared by Zn-MOF reached 84.12 %, which was 10.03% higher than that catalyzed by 4-dimethylamino pyridine which was the state-of-the-art catalyst for this reaction. The banana cellulose nanofibres grafted with ε-CL reactions followed the coordination-insertion mechanism, which was confirmed by the theoretical calculations using the Materials Studio software. The cytotoxicity results indicated that BGCL was not only non-toxic to Hela cells but also promoted Hela cell growth within a certain concentration range. Therefore, this study demonstrated the promising potential of BGCL for biomedical applications, and the high efficiency, non-toxicity, and stability of Zn-MOF as the catalyst. Further, this will provide a theoretical basis for the application of MOFs as catalysts in polymerization reactions.
研究领域:
材料科学
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生物医学工程
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催化化学
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PubMed
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2021
·
IF 6.953
Bingqing Huang,Zhigang Zhang,Nengshui Ding,Yuanhong Zhuang,Guoguang Zhang,Peng Fei
To further improve the performance of chitosan in food processing and preservation, this study investigated the grafting of the caffeic acid onto the chitosan in non-enzymatic and enzymatic systems. Result suggested that the caffeic acid was successfully incorporated into the chitosan in the non-enzymatic system, and the grafting ratio of modified chitosan (CA@CTS-N) was 7.49%. Moreover, lipase had a significant positive effect on the grafting reaction of the chitosan, and the modified chitosan prepared in enzymatic system (CA@CTS-E) obtained a higher grafting ratio, which was 11.82%. In both systems, the carboxyl of the caffeic acid was bonded to the amino of the chitosan and formed carbonyl ammonia. After the introduction of foreign group, many changes occurred in the functional properties of the modified chitosan. First, the water solubility of the chitosan was significantly improved from 0.00285 (native chitosan, CTS) to 0.221 (CA@CTS-N) and 0.774 g/100 mL (CA@CTS-E). The caffeoyl had a significant impact on the emulsifying properties of the chitosan. Compared with those of CTS, the modified chitosan had stronger antioxidation and antibacterial activities against Escherichia coli , Staphylococcus aureus , and Candida albicans . Finally, the pork treated with the modified chitosan exhibited longer shelf life than that treated with CTS.
研究领域:
食品科学
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化学
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生物技术
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PubMed
高影响因子
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