| Modifying sulphanilic acid-phenol-formaldehyde condensates (SPF) with sodiumlignosulphonate (LS) allows for both the grafting (GSPF) and blending (BSPF) of a series ofproducts from SPF and LS with different LS content. The grafted macromolecule SPF-g-LS wasconfirmed to exist in GSPF by static light scattering (SLS) and Fourier-Transform infrared (FTIR)spectroscopy. GSPF formed different adsorption configurations on cement particles than BSPF,which ultimately endowed GSPF with better performance in various aspects of adsorption,adsorption capacity, adsorption layer thickness, zeta potential, paste fluidity, bleeding-inhibiting,and mortar fluidity at identical LS contents, because of the high charge density and large sterichindrance of the SPF-g-LS macromolecule. The comprehensive analysis shows that GSPF hasthe optimum cost performance when LS content is30%, namely GSPF3.SPF was also modified by black liquor via the following approach and modified productHSPF was obtained: analyzing the optimum procedure for the preparation of lignin from blackliquor by acidulation precipitation, determining the optimum procedure for the sulphonation oflignin by staged orthogonal design (hydroxymethylation first, then sulphonation second), andmodifying black liquor with sulphonated lignin (HL) under the optimum condition. At identicalHL (or LS) contents, HSPF possesses a greater degree of adsorption, adsorption capacity andpaste fluidity than GSPF. The contributions of the samples to zeta potential are listed indescending order: SPF, HL, and LS. The differences in performance between HSPF and GSPFresulted from the higher sulphonation degree and more appropriate molecular weight of HL,which endowed HSPF with significant steric effect and electrostatic repulsion and affected theproperties of the modified product.The paper would be helpful in exploiting renewable resources effectively and substitutingfor petrochemical in part, and the methods could be adopted in practice. |
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