FOOD HYDROCOLLOIDS
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2019
·
IF 5.839
Peiyuan Zhou,Mohamed Eid,Wenfei Xiong,Cong Ren,Tingyang Ai,Ziyu Deng,Jing Li,Bin Li
Cold and hot water extracted polysaccharides (CP and HP) were isolated from Plantago ovata seed husk at 25 and 85 °C, respectively. Their rheological properties were systematically investigated and compared. Different concentrations and temperatures were studied to evaluate the viscoelastic properties of the two fractions. It was found that CP solutions behaved as viscous fluids, while HP solutions preferred to exhibit as gel-like structure. The sol-gel transition process of HP was evaluated and the gel point was determined to be 4.8 mg/mL by Winter-Chambon method in water at 25 °C. The steady flow sweep investigated the viscosity properties of CP solutions and two critical concentrations were found, which locating the transition from the dilute to semi-dilute region, and from the semi-dilute to concentrated region. In addition, the two fractions could form thermo-reversible weak gels, and the gelation temperatures of them increased with the increase of concentration. It is evident that both polysaccharides have significant potential for application in food industry.
研究领域:
食品科学
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生物化学
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产品关联
DOI
高影响因子
JOURNAL OF VINYL & ADDITIVE TECHNOLOGY
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2016
·Vol. 24
·期 3
·239-247
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IF 1.219
Wenbo Liu,Weiwei Jiao,Fan Yang,Rongguo Wang,Lizhi Li,Weicheng Jiao
With excellent mechanical property, thickening and curing performance, vinyl ester resin (VE) has been widely used as a resin matrix of sheet molding compound (SMC). The rheological behavior of vinyl ester resin during thickening process was investigated by rotational rheometer. It showed that the initiator affected the rheological behaviors of the resin significantly, which should be inhibited by rapid thickening rate. By introducing the gel point for thickening process, the optimization principle of thickener was established. Both single thickeners cannot meet the thickening requirement considering their thickening mechanisms which were confirmed by Fourier infrared spectrometer (FTIR). Complex thickener was proposed with its optimal ratio determined as 1.2% MgO to 3.0% TDI by the optimization principle. It was demonstrated that complex thickening system had excellent performance in thickening and antithickening behaviors as well as extended storage life of more than 60 days. J. VINYL ADDIT. TECHNOL., 24:239–247, 2018. © 2016 Society of Plastics Engineers
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
JOURNAL OF APPLIED POLYMER SCIENCE
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2015
·Vol. 132
·期 20
·
IF 1.768
Yaobin Liu,Zhiqiang Fan
Two tribromide compounds, 1,3-(propanoic acid, 2-bromo-)-2-(2-bromo-1-oxopropylamino)propyl ester (A 1 ) and trimethylolpropane tris(2-bromopropionate) (A 2 ), were synthesized. By Cu/ N,N,N′,N′,N″ -pentamethyldiethylenetriamine (PMDETA)-mediated radical addition-coupling polymerization (RACP) of 2-methyl-2-nitrosopropane (MNP) with the tribromide compounds, two types of hyperbranched polymers were synthesized under mild conditions, respectively. Polymerization degrees of the polymers increased with time gradually, which is in line with a step-growth polymerization mechanism. By tracing the polymerization process by gel permeation chromatography and NMR analysis, proper reaction conditions to get hyperbranched polymers was obtained. Based on the results of NMR analysis on the polymer chain structure, mechanism of forming hyperbranched polymer has been proposed, which includes formation of carbon radicals from the tribromo monomer through single electron transfer, their reaction with MNP to form nitroxide radicals, and cross-coupling reaction of the nitroxide radicals with other carbon radicals. The gelation point of the A 2 -MNP system is larger than that of the A 1 -MNP system, indicating that probability of intramolecular cyclization in A 2 -MNP RACP system is higher than the A 1 -MNP system. The reactivity of —NHCOCH(CH 3 )Br group of A 1 is lower than its two —OCOCH(CH 3 )Br groups, and this resulted in longer distance between two adjacent branch points in the hyperbranched polymer of A 1 -MNP than the A 2 -MNP system. It is possible to adjust the chain structure of RACP-based hyperbranched polymer by changing the reactivity of the functional groups in A 3 monomer. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132 , 41972.
研究领域:
高分子化学
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聚合物合成
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功能高分子
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材料化学
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有机合成方法学
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DOI
高影响因子
FOOD HYDROCOLLOIDS
·
2024
·
IF 11
Chenzhi Wang,Yan Li,Wei Xiong,Qiang Liang,Xin Hua,Pu Xuan,Wei Lin,Yingzheng Yao
The correlation between the structural parameters of droplets and rheological properties of O/W high internal phase Pickering emulsions (HIPPEs) stabilized by soy protein isolate (SPI) nanoparticles was elucidated, with a volume fraction of dispersed phase ( ϕ ) above the closest packing density (74%). The structural basis of SPI nanoparticles was confirmed to be spherical heat-induced protein aggregates, which had moderate wettability and excellent interfacial activity. The structural parameters of emulsion droplets (contact length L , diameter D , length d 1 , width d 2 , the number of adjacent contact droplets Z ), and the stability and rheological properties of HIPPEs were characterized by the confocal laser scanning microscopy (CLSM), diffusing wave spectroscopy (DWS), and mechanical rheometer respectively. The results of CLSM indicated the transition of droplets from spherical to polyhedral shapes as increased ϕ , accompanied by an increased L and Z . The rheological and stability analysis confirmed the widened linear viscoelastic range, elevated gel point ( ε c ), and the extended half−life of the intensity autocorrelation function of HIPPEs as ϕ increased. Moreover, the loss factor (tan δ ) remained constant at 0.1 within the ϕ of 74%–86%, revealing the solid−like nature of HIPPEs. The correlation between ϕ , structural parameters of droplets, and rheological properties of HIPPEs was further analyzed. The nonlinear regression fitting between the L / D and G ' (elastic modulus) yielded a better fitting effect than d 1 / d 2 and Z , suggesting an intrinsic correlation between emulsion structure and rheology. In summary, this study elucidated the intricate relationship between ϕ , droplet structure, and rheological properties of HIPPEs, offering a research foundation and theoretical basis for the development and application of protein particle−stabilized HIPPEs.
研究领域:
胶体科学
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流变学
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食品科学
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材料科学
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产品关联
DOI
高影响因子
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