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Determination of the Coreactant Level in Crosslinked Polyurethane System by FTIR
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作者 zheng chen zhou kat chen gao-bin 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2018年第S1期19-20,共2页
Infrared spectrum is a general quantitation method which can be used to determine the concentration of a certain component in mixture.We proposed that it could also be used to determine the coreactant level of a react... Infrared spectrum is a general quantitation method which can be used to determine the concentration of a certain component in mixture.We proposed that it could also be used to determine the coreactant level of a reactive system.A two-part polyurethane film was used as a model system.The results showed that the height ratio of ring mode signal in urea and C—O signal in polyester polyol can be used to calculate the ratio of the two reactants.The assignments of the peaks were studied by in-situ reaction monitoring with moisture level changes and deuteration methods.The applicable conditions of this calibration curves were also discussed. 展开更多
关键词 Infrared spectrum Two-part POLYURETHANE In-situ reaction MONITOR DEUTERATION experiment
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Applications of DOSY NMR in the Chemical IndustryApplications of DOSY NMR in the Chemical Industry
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作者 YUAN Ling XU Jian-ping YANG Xiu-han 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2016年第S1期447-448,共2页
DOSY(diffusion ordered spectroscopy)NMR is a technique that separates NMR signals of different species according to their diffusion coefficients.It is a powerful technique to provide solid characterization evidence fo... DOSY(diffusion ordered spectroscopy)NMR is a technique that separates NMR signals of different species according to their diffusion coefficients.It is a powerful technique to provide solid characterization evidence for various applications in the chemical industry.Encapsulation and functional polymer grafting are two important capabilities in the chemical industry for new product development with challenging characterization requirements.Model systems of encapsulation and grafted polymer were studied and the characterization methods were set up by DOSY NMR. 展开更多
关键词 DOSY NMR DIFFUSION ENCAPSULATION Grafted polymer characterization
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Piloting Study on Biofouling Control of Reverse Osmosis System in Steel Mill Wastewater Reuse
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作者 Cheng Yang Tina Arrowood Jon Johnson 《Journal of Environmental Science and Engineering(A)》 2017年第9期453-461,共9页
The biofouling of RO (Reverse Osmosis) system is one of the most common problems in highly contaminated demineralization and wastewater reuse system. The biological fouling occurs due to the bacteria growth and prol... The biofouling of RO (Reverse Osmosis) system is one of the most common problems in highly contaminated demineralization and wastewater reuse system. The biological fouling occurs due to the bacteria growth and proliferation under nutritive environment, resulting in a dramatic increase of dP (differential pressure) in the RO system, which requires frequent system shutdown for cleaning. This paper discusses the effectiveness of low-dP RO element and periodic flushing on the biofouling scheme of industrial steel mill wastewater reuse system. The low-dP RO element is able to provide low RO system dP, which is expressed to be lower biofouling starting point during the industrial system operation. However, the periodic flushing utilizes fresh water to remove the biofilm deposit along with feed channel. The long term operation performance demonstrated strong caustic is effective in removing the biofilm and recovering RO system performance. It is experimentally validated that, in the case of a high biofouling environment, low-dP RO element and periodic flushing is able to extend the cleaning cycles by 36.6% and 11.4%, respectively. Meanwhile, a joint application of both methods is proven to improve the biofouling control and extend the cleaning cycle by 62.5%, as compared to standard RO technology. 展开更多
关键词 RO (Reverse Osmosis) BIOFOULING MEMBRANE dP (Differential Pressure) wastewater reuse
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Rational construction of self-assembly azobenzene derivative monolayers with photoswitchable surface properties 被引量:2
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作者 Yu Zhang Peng Gao +2 位作者 Qin Yue Peter Trefonas Yonghui Deng 《Chinese Chemical Letters》 SCIE CAS CSCD 2018年第11期1661-1665,共5页
Photo-responsive azobenzene (ABZ) derivatives with different end groups (R) as photoswitchable molecules were employed to construct self-assembled monolayers (SAMs) on silicon substrate by using 3-glycidoxypropy... Photo-responsive azobenzene (ABZ) derivatives with different end groups (R) as photoswitchable molecules were employed to construct self-assembled monolayers (SAMs) on silicon substrate by using 3-glycidoxypropyltrimethoxysilane (GPTS) as the bridging molecules. The assembly process was optimized by changing various parameters, including the type and concentration of ABZ derivatives, reaction time, etc. The obtained SAMs were fully characterized and evaluated using UV spectroscopy, atomic force microscope (AFM), elllipsometer, static contact angle and X-ray photoelectron spectroscopy (XPS). It is found that the end group property of azobenzene derivatives is critical to the obtained SAMs' photoresponsive properties. Compared with hydrophobic compounds (4-(4'-aminophenylazo) benzoic acid, ABZ-CF3), the hydrophilic compounds (4-(4'-aminophenylazo) benzoic acid, ABZ-COOH) show excellent reversible photoswitching performance with a large contact angle change of 35° under oDtimized process, and the SAMs are removable bv thermal treatment at 240 ℃ in air for onlv 5 min. 展开更多
关键词 SELF-ASSEMBLY MONOLAYER AZOBENZENE PHOTOSWITCH Surface treatment
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Quantitative Analysis of Azodicarbonamide in Insulation Layers of Extruded Cables by HPLC–UV Detection 被引量:1
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作者 Sensen Shen Cuilan Chang +3 位作者 Chenbo Shen Harvey Xu Shawn Miao Scott Wills 《Journal of Analysis and Testing》 EI 2021年第4期370-378,共9页
Azodicarbonamide(ADC),which has been abundantly used in the creation offoamed plastics as a blowing and foaming agent,has attracted more and more attention in recent years due to the health risks associated with its c... Azodicarbonamide(ADC),which has been abundantly used in the creation offoamed plastics as a blowing and foaming agent,has attracted more and more attention in recent years due to the health risks associated with its consumption.ADC is actually on the REACH(Registration,Evaluation,Authorization and Restriction of Chemicals)regulation Candidate List of Substances of Very High Concern,and the residual content in products needs to be confirmed by the end users according to regulations.Therefore,the determination and monitoring of ADC in plastic products is necessary and crucial not only for the growth of ADC global market but also for the health of the public.In this work,a quantitative method for ADC in insulation layers of cables was developed by using optimized total dissolution methodology(TDM)for sample preparation followed by HPLC under HILIC conditions with UV absorbance detection.The linear range of this method was 6–600μg·g^(-1) ,and the limit of detection(LOD)and limit of quantitation(LOQ)were 0.94 and 3.1μg·g^(-1) in solution,respectively.The method has good recovery and precision,and is easy to operate.It meets the needs of the industry and is conducive to the growth of ADC global market.This method is expected to be applicable to ADC quantitation in other polyolefin products. 展开更多
关键词 AZODICARBONAMIDE Total dissolution methodology HPLC–UV Cable insulation layers
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