摘要
通过木质素磺酸钙(LC)与1,3-丙磺酸内酯(PS)在NaOH的催化下制备丙磺酸木质素醚(PSLC)高效减水剂,并系统地研究了投料比、反应温度、反应时间对产物净浆流动度的影响.结果表明,当m(PS)∶m(LC)=1.27∶1、反应温度为80℃、反应时间为24h时,在水灰比为0.29的条件下,PSLC5的水泥净浆流动度为(250±1)mm.采用核磁共振波谱(NMR)、傅里叶变换红外光谱(FTIR)、凝胶渗透色谱(GPC)、X射线光电子能谱(XPS)、扫描电子显微镜(SEM)及热重分析(TGA)系统研究了 PSLC的结构与热性能.还探索了其水泥净浆流动度、坍落度、抗压强度、减水率,均优于商用萘系N06减水剂.PSLC优异的减水效果主要是由于其吸附在水泥颗粒表面上有较高的静电斥力.
Abstract
Concrete admixture is one of the important components of concrete.As a kind of concrete admixture,the main function of water reducing agent is to reduce the water consumption of concrete without affecting its workability.Lignosulfonate superplasticizer,an environmentally friendly product,is prepared from pulp waste liquid as raw material with a simple production process.In this work,the novel type of propanesulfonate lignin ether(PSLC)superplasticizer was prepared by reaction of 1,3-propyl sulfonate(PS)and calcium lignosulfonate(LC)under NaOH catalyst.The effects of monomer feeding ratio,reaction temperature and reaction time on the fluidity of cement slurry were systematically studied.PSLC5 sample showed the fluidity of cement slurry of(250±1)mm with water cement ratio of 0.29 when synthesis condition was m(PS)∶m(LC)=1.27∶1 at 80 ℃ for 24 h,which was significantly better than that of raw LC(less than 80 mm).The structure and thermal properties of PSLC were characterized systematically through nuclear magnetic resonance spectroscopy(1H-NMR),Fourier transform infrared spectroscopy(FTIR),gel permeation chromatography(GPC),X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM)and thermo-gravimetric analysis(TGA).When the water cement ratio was 0.29,the fluidity of PSLC5 cement slurry was(250±l)mm better than that of N06((197±1)mm).After 60 min of static settling,the damage of PSLC5's flowability was only 3.2％,while N06 almost solidified without flowing.In order to achieve the same slump((215±5)mm)and spread((600±5)mm)of the concrete,the demand for PSLC5 was much less than for N06.The compressive strength of PSLC5 concrete was 22.3-43.8 MPa,which was higher than that of N06 at 3 days,7 days,28 days,respectively.And the water reducing rate of PSLC5 was 13％,higher than N06's 9.3％.In conclusion,PSLC5 exhibits better performance in concrete water reduction compared to N06.The excellent water reducing effect of PSLC is mainly due to the high electrostatic repulsion generated during absorption on the surface of cement particles.
基金项目
国家自然科学基金(22275041)
贵州省科技计划(黔科合基础-ZK[2021]重点023)
垒知创新基金(LETSGrp2020042402)
贵州大学引进人才科研(DCRE-2023-15)
维普
万方数据