APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY
·
2011
·Vol. 165
·期 2
·666-675
·
IF 1.879
Chen Sheng,Liu Zhiguo,Chen Jian,Wu Jing
Escherichia coli is one of the most commonly used host strains for recombinant protein production. More and more research works on the production of recombinant protein indicate that extracellular production throughout a culture medium is more convenient and attractive compared to intracellular production. In present work, inducing temperature and isopropyl β- d -1-thiogalactopyranoside (IPTG) concentration were investigated to decrease the formation of inclusion body and increase the amount of soluble recombinant cutinase initially. Enzyme activity in the culture medium reached to 118.9 U/ml at 64 h of culture, and no inclusion body was detected in cytoplasm under the inducement condition of 0.2 mM IPTG and 30°C. In addition, it was found that a large amount of cutinase had been accumulated in periplasm since 16-h cultivation under the same inducement condition. Therefore, glycine and surfactant sodium taurodeoxycholate (TDOC) were further used to promote the leakage of recombinant cutinase from periplasm. Supplied with 100 mM glycine and 1 mM TDOC, the amount of cutinase in periplasm decreased remarkably, and the activity in the culture medium reached to 146.2 and 149.2 U/ml after 54 h of culturing, respectively.
研究领域:
生物工程
·
分子生物学
✓ 已验证
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2013
·Vol. 131
·期 3
·
IF 1.395
Mingliang Xin,Yujie Ma,Kai Xu,Mingcai Chen
Octyl gallate (OG), dodecyl gallate (DG), and hexadecyl gallate (HG) were synthesized and characterized by Fourier transform infrared (FTIR) and NMR, and their thermal stability was measured by thermogravimetric analysis (TGA). The antioxidant effect of these derivatives in polypropylene (PP) was measured by oxidation induction temperature measurement on DSC, and by measurement of carbonyl groups in the polymer on attenuated total reflectance FTIR spectroscopy after they were aged at 120°C. The results indicated that the gallate derivatives could provide long-term stabilization to PP under conditions of oxidative degradation. The antioxidant performance of HG with longer alkyl chain was superior to the OG and DG, making the former a good candidate to be used as antioxidant additive in PP. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131 , 39850.
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 ENGINEERING AND SCIENCE
·
2022
·Vol. 62
·期 12
·4214-4225
·
IF 2.573
Wenrong Zhao,Ming Lu,Bin Wang,Xiaoqing Liu,Shuang Wang
The effect of iron-containing substances with different forms on the properties of carbon-black filled natural rubber compound is discussed. The ionic iron substances (FeCl 2 , FeCl 3 , Fe(SA) 3 ) have a detrimental effect on the rubber. Based on the oxidation induction temperature values, the relative deteriorating effects of ionic iron substances on the rubber are in the order: Fe(SA) 3 > FeCl 3 ≈ FeCl 2 . Not only are the metal ions (Fe 2+ , Fe 3+ ) with adjacent stable oxidation states catalytically active in degrading rubber, but also the counterions have an influence on the effect of oxidation, particularly the stearic anion. Ionic iron materials can decrease the molecular weight, especially for the case of Fe(SA) 3 as measured by gel permeation chromatography. Due to the degrading effect on the rubber molecules, Fe(SA) 3 brings about a torque decrease in moving die rheometer and evident decrease of the Mooney viscosity at 100°C, which is different from the effects of Fe 2 O 3 and 304L-Fe. The insoluble iron substances behave more like hard fillers. Additionally, Fe(SA) 3 remarkably alters the bound rubber content and the tensile properties after aging via two different process (scission and crosslinking). Overall, this work has a thorough comparison of effect of iron-containing materials on rubber aging and provides useful inspiration to protect the rubber from deterioration by foreign reagents and regulating the rubber stability and degradation rate via introducing degradative metal ions.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2017
·Vol. 7
·期 74
·46678-46689
·
IF 3.108
Chenyang Li,Zhenhuan Li,Maliang Zhang,Bowen Cheng
SiC-fixed organophilic montmorillonite (OMMT@SiC) hybrid particles, with various proportions of SiC, were fabricated by electrostatic self-assembly in the presence of CTAB. Then, their PPS composites were prepared by melt-compounding. The results showed that the oxidation resistance and mechanical properties of PPS/OMMT@SiC composites was enhanced. When SiC content reached 5 wt%, the oxidation induction temperature of the PPS/OMMT@SiC composite achieved its maximum 513.1 °C, which was 40.9 °C higher than that of pure PPS. Meanwhile, the oxidation induction time of the obtained composite achieved a maximum of 25.2 min. These enhancements were attributed to the existence of the SiC, which prevented the aggregation of OMMT and facilitated OMMT to be further exfoliated in the PPS matrix. The sulfur atoms of PPS formed chemical bonds with SiC, meanwhile, a part of the surface hydroxyl groups of SiC formed hydrogen bonds with PPS, thus weakening the oxidation activity. OMMT and SiC effectively postponed the thermal oxidative degradation of PPS due to synergistic effects.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2023
·Vol. 148
·期 22
·12445-12454
·
IF 4.4
Moraczewski Krzysztof,Szabliński Krzysztof
In this paper, the research findings about the impact of polydopamine and tannic acid coatings on specific thermal properties of polylactide are discussed. The influence of deposited coatings on the resistance to oxidation, heat resistance, and the temperatures of phase transitions was determined. Therefore, the oxidation induction temperature, thermogravimetry, and differential scanning calorimetry studies were carried out. To gain a deeper understanding of the findings, mass measurements for the samples before and after the deposition process were conducted, as well as scanning electron microscopy studies. Studies have shown that the application of coatings can improve the resistance of polylactide against oxidative and thermal degradation. However, these coatings have minimal impact on the intensity and temperature of phase transformations. The polylactide showed increased thermal resistance when coated with polydopamine, whereas tannic acid coating was found to be more effective in increasing oxidation resistance. The differences observed were likely caused by variations in the structure of the coatings applied, impacting the level of oxygen diffusion and heat transfer within the material.
研究领域:
材料科学
·
高分子化学
·
表面工程
✓ 已验证
DOI
高影响因子
JOURNAL OF POLYMER ENGINEERING
·
2019
·Vol. 39
·期 6
·556-564
·
IF 1.072
Wenxin Han,Jianjun Lu,Jingyi Ren,Dandan Lian,Junde Xing
Polyphenylene sulfide (PPS) is easily oxidized at high temperature, which greatly limits its applications. In this study, a nano-SiO 2 compound antioxidant (SiO 2 -g-AO) was prepared and incorporated into PPS by melt compounding to obtain PPS/SiO 2 -g-AO composites. SiO 2 -g-AO was prepared by reacting 3-(3,5-di-tert-butyl-4-hydroxyphenyl) (antioxidant AO) with an aminosilane coupling agent (KH792). Fourier transform infrared (FTIR) spectroscopy, energy dispersive spectroscopy (EDS) and thermogravimetric analysis (TGA) confirmed that the antioxidant AO was successfully immobilized on the surface of SiO 2 and the thermal stability was improved. Scanning electron microscopy (SEM) images showed that SiO 2 -g-AO was uniformly dispersed in PPS. It has been found that the crystallinity and mechanical properties of PPS composites improved, and the dynamic oxidation induction temperature (OIT) increased in the range of 16.7°C–21.1°C. A synergistic anti-oxidation model of nanoparticles and antioxidants, namely a multi-stage antioxidant system, was established by comprehensive analysis of experimental results. The synergistic anti-oxidation model provides a new idea for the antioxidant modification of polymer composites.
研究领域:
材料科学
·
高分子科学
·
化学工程
✓ 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）