疏水化水溶性两性纤维素接枝共聚物与粘土的相互作用

Interactions between the Hydrophobically-modified Water-soluble Amphoteric Cellulosic Graft Copolymer and Clay

运用紫外光谱法研究了疏水化水溶性两性纤维素接枝共聚物(羧甲基纤维素接枝丙烯酰胺及N,N-二甲基辛基(2-甲基丙烯酰氧乙基)溴化铵的共聚物,CGAO)在粘土上的吸附,考察了聚合物浓度、无机盐浓度、温度、pH、表面活性剂和粘土浓度等因素对CGAO在粘土上吸附量的影响,以及通过X射线衍射分析了CGAO在粘土上的吸附位置.结果表明,CGAO在粘土上的吸附规律与一般聚合物有很大差别,而且CGAO未深入到粘土晶层间,只在其表面吸附.粘土与CGAO作用前后的粒度分析表明CGAO对粘土粒子有很好的桥接聚集作用.扫描电镜分析显示粘土与CGAO作用后,其颗粒形态发生了显著变化.

Hydrophobically-modified water-s oluble polymers are essentially hyd rophilic polymers which also contain a small proportion(up to a few mole percent )of strongly hydrophobic groups,usu ally in the form of pendant side chains or terminal grou ps.In recent years,they are attracting much increasing attention becau se of their unusual rheological and amphi pathic properties in the presence of added salt,and potential industria l ap-plications.One of the applications directly relates to clay,for instan ce,the adsorption of hydrophobic associative polyacrylamide on clay has been studied.However,the interaction of hydrophobically-modified water-solu ble amphoteric polymer with clay has bee n so far hardly investigated includi ng the adsorption.In the previous paper,the hydrophobically-modified water-soluble amp hoteric cellulosic graft copolymer(carboxymethylcellulose grafting a crylamide and dimethyloctyl (2-methacryloxyethyl )ammonium bromide,abbr.CGAO)has been prepared for the first time.In this paper,the adsorption amount (Γ)of CGAO on clay has been investigated as a function of co ncentration of CGAO and NaCl,temperature,pH,surfactant and clay content by means of the ultraviolet s pectrum.The results indicate thatΓtends to increase with the increasin g of CGAO concentration,but no saturati on of adsorption is observed as in the case of the general polymer;Γsharply rises up with the increment of NaCl co ncentration up to 1mol ·L -1 ;Γcontinuously decreases at temperature from 25℃to 60℃or pH from 3.6to 10.3;Γexhibits an interesting concave cur ve with the concentration enhancement of SDS from 0to 14mmol ·L -1 or CTAB from 0to 1.3mmol ·L -1 ;at approximate cmc (critical micelle concentration)of SDS or CTAB,Γapproaches a minimum;andΓreduces with the increase of clay content from 1to 5g ·dL -1 .CGAO is only adsorbed onto the surfa ce of clay,but not into the inter-cry stal layer as is verified by the layer distance(d 001 )of the crystal obtained by X-ray diffraction.Laser particle size analysis of clay reveals that CGAO can effecti vely encapsulate and bridge clay particles,as is also confirmed by the scanning electron microscope,and t he complex particle size of clay /CGA O cuts down in the presence of SDS.