期刊文献+
共找到6篇文章
< 1 >
每页显示 20 50 100
Analysis of Air Voids Evolution in Cement Pastes Admixed with Non-ionic Cellulose Ethers 被引量:3
1
作者 欧志华 XIAO Yi +3 位作者 王菁菁 MA Baoguo JIANG Longmin JIAN Shouwei 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2018年第4期915-923,共9页
Four cellulose ethers(CEs) were compared for their effects on the pore structure of cement paste using mercury intrusion porosimetry. The experimental results show that the total pore volume and porosity of cement p... Four cellulose ethers(CEs) were compared for their effects on the pore structure of cement paste using mercury intrusion porosimetry. The experimental results show that the total pore volume and porosity of cement pastes containing the four cellulose ethers are significantly higher than that of the pure cement pastes and the total pore volume and porosity of cement pastes containing HEC(hydroxyethyl cellulose ether) or low viscosity cellulose ethers are low in four CEs. By changing the surface tension and viscosity of liquid phase and the strengthening of liquid film between air voids in cement pastes, CEs affect the formation, diameter evolution and upward movement of air voids and the pore structure of hardening cement paste. For the four CEs, the pore volume of cement pastes containing HEC or low viscosity cellulose ethers is higher with the diameter of 30-70 nm while lower with the diameter larger than 70 nm. CEs affect the pore structure of cement paste mainly through their effects on the evolvement of the small air voids into bigger ones when the pore diameter is below 70 nm and their effects on the entrainment and stabilization of air voids when the pore diameter is above 70 nm. 展开更多
关键词 cellulose ethers cement pastes pore structure air voids diameter evolution
下载PDF
Influence of Cellulose Ethers on Hydration Products of Portland Cement 被引量:2
2
作者 马保国 欧志华 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2011年第3期588-593,共6页
Cellulose ethers are widely used to mortar formulations,and it is significant to understand the interaction between cellulose ethers and cement pastes.FT-IR spectra,thermal analysis and SEM are used to investigate hyd... Cellulose ethers are widely used to mortar formulations,and it is significant to understand the interaction between cellulose ethers and cement pastes.FT-IR spectra,thermal analysis and SEM are used to investigate hydration products in the cement pastes modified by HEMC and HPMC in this article.The results show that the hydration products in modified cement pastes were finally identical with those in the unmodified cement paste,but the major hydration products,such as CH(calcium hydroxide),ettringite and C-S-H,appeared later in the modified cement pastes than in the unmodified cement paste.The cellulose ethers decrease the outer products and increase inner products of C-S-H gels.Compared to unmodified cement pastes,no new products are found in the modified cement pastes in the present experiment.The HEMC and HPMC investigation shows almost the same influence on the hydration products of Portland cement. 展开更多
关键词 cellulose ethers hydration product portland cement
下载PDF
Early Stage Hydration Mechanism of Cellulose Ether Modified Thin Layer Cement Pastes 被引量:7
3
作者 马保国 SU Lei +1 位作者 JIAN Shouwei SONG Xuefeng 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2012年第6期1172-1176,共5页
The early stage hydration mechanism of cellulose ether modified thin layer cement pastes was studied, using brick as the matrix. Samples of 6 h, 24 h, and 3 d and 7 d hydration time were analyzed to study the hydratio... The early stage hydration mechanism of cellulose ether modified thin layer cement pastes was studied, using brick as the matrix. Samples of 6 h, 24 h, and 3 d and 7 d hydration time were analyzed to study the hydration law on the surface of high water-absorbing matrix. Hydration products were qualitatively and semi-quantitatively analyzed using XRD, TG-DSC-DTG, FTIR and SEM. The experimental results show that there is no enough water for 2 mm thick cement pastes to hydrate, because of rapid water absorption of matrix. Trace amounts of Ca (OH)2 was detected after three days hydration. With the prolongation of hydration time, the category and concentration of hydration products do not change. Compared with 2 mm thick cement pastes, 6 mm thick cement pastes and 10 mm thick cement pastes have lower dehydration rate and water loss. The humidity field of the cement paste show different changes within the same time. 6 mm thick cement paste and 10 mm thick cement pastes have longer time and more water to hydrate. Ca(OH)2 and ettringite were detected after 6 hours hydration and the concentrations of hydration products increased from 24 hours to 7 days. 展开更多
关键词 cellulose ether thin layer cement pastes high water-absorbing matrix hydration products
下载PDF
Hydration Heat Effect of Cement Pastes Modified with Hydroxypropyl Methyl Cellulose Ether and Expanded Perlite 被引量:2
4
作者 苏雷 MA Baoguo +2 位作者 JIAN Shouwei ZHAO Zhiguang LIU Min 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2013年第1期122-126,共5页
Hydration heat effect of cement pastes and mechanism of hydroxypropyl methyl cellulose ether (HPMC) and expanded perlite in cement pastes were studied by means of hydration exothermic rate, hydration heat amount, FT... Hydration heat effect of cement pastes and mechanism of hydroxypropyl methyl cellulose ether (HPMC) and expanded perlite in cement pastes were studied by means of hydration exothermic rate, hydration heat amount, FTIR and TG-DTG. The results show that HPMC can significantly delay the hydration induction period and acceleration period of cement pastes. As mixing amount increased, hydration induction period of cement pastes enlarged and accelerated period gradually went back. At the same time, the amount of hydration heat gradually decreased. Expanded perlite had worse delay effects and less change of hydration heat amount of cement pastes than HPMC. HPMC changed the structure of C-S-H during cement hydration. The more amount of HPMC, the more obvious effect. However, EXP had little influence on the structure of C-S-H. At the same age, the content of Ca (OH)2 in cement pastes gradually decreased as the mixing amount increase of HPMC and expanded perlite, and had better delay effect than that single-doped with HPMC or expanded perlite when HPMC and expanded nerlite were both dooed in cement pastes. 展开更多
关键词 hydroxypropyl methyl cellulose ether expanded perlite cement pastes hydration heat hydrationprocess
下载PDF
Thermal Behavior and Thermal Safety of Nitrate Glycerol Ether Cellulose 被引量:1
5
作者 XU Si-yu ZHAO Feng-qi +5 位作者 YI Jian-hua GAO Hong-xu SHAO Zi-qiang HAO Hai-xia HU Rong-zu PEI Qing 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2012年第3期516-519,共4页
The thermal behavior, nonisothermal decomposition reaction kinetics and specific heat capacity of nitrate glycerol ether cellulose(NGEC) were determined by thermogravimetric analysis(TGA), differential scanning ca... The thermal behavior, nonisothermal decomposition reaction kinetics and specific heat capacity of nitrate glycerol ether cellulose(NGEC) were determined by thermogravimetric analysis(TGA), differential scanning calori- metry(DSC) and microcalorimetry. The apparent activity energy(Ea), reaction mechanism function, quadratic equa- tion of specific heat capacity(Cp) with temperature were obtained. The kinetic parameters of the decomposition reac- tion are Ea=170.2 kJ/mol and lg(A/s^-l)=16.3. The kinetic equation isf(α)=(4/3)(1-α)[-ln(1-α)]^1/4. The specific heat capacity equation is Cp=1.285-6.276×10^-3T+1.581×10^-5T^2(283 K〈T〈353 K). With these parameters, the thermal safety properties of NGEC were studied, such as the self-accelerating decomposition temperature(TSADT), critical temperature of thermal explosion(Tb) and adiabatic time-to-explosion(tTlad). The results of the thermal safety evalua- tion of NGEC are: TSADV=459.6 K, Tb=492.8 K, tTlad=0.8 S. 展开更多
关键词 Nitrate glycerol ether cellulose Thermal decomposition reaction kinetics Thermal safety property
下载PDF
Preparation of Carboxymethylcellulose from Waste Paper
6
作者 HE Jie WANG Dali +5 位作者 LONG Lirong HUANG Yali CUI Chunxiang YI Jiajia YANG Shengyang WANG Yuchang 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2021年第4期562-568,共7页
We aimed at producing sodium carboxymethylcellulose (CMC) from waste paper cellulose.For this etherification,the raw material was waste paper,the cellulose was initially alkalized with NaOH,the etherifying agent was s... We aimed at producing sodium carboxymethylcellulose (CMC) from waste paper cellulose.For this etherification,the raw material was waste paper,the cellulose was initially alkalized with NaOH,the etherifying agent was sodium chloroacetate,and the reaction medium was water or ethanol.The method provided by us,i e,a method for preparing CMC from waste paper,was environment-friendly,could be easily implemented,and could be conveniently applied to make waste paper efficiently used with high profit,and to expand the range of usable raw materials for CMC production.We successfully synthesized CMC and prepared CMC plastic membrane.This practice changes waste into valuables,which is beneficial to our living environment.For preparation of CMC,one of the crucial factors is appropriate pretreatment of the cellulose from waste paper.The pretreatment was done with a self-built hydrolysis method.We experimentally examined the effects of the mass ratios of reactants,reaction temperature,time,and reaction environment of homogeneous or heterogeneous on CMC yield.The innovative points of this research could be stated as follows:the reaction activity of cellulose was improved by pre-hydrolysis;synthesizing CMC with cellulose from waste paper changes waste into valuables is beneficial to our living environment;and a freezing treatment for the cellulose-alkali mixture was innovatively added.The effects were exhibited by a desired final conversion efficiency. 展开更多
关键词 CMC cellulose ETHERIFICATION cellulose ether MEMBRANE
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部