【作者】 梁虎南；

【导师】 杨淑蕙；

【作者基本信息】 江南大学 ， 制浆造纸工程， 2009， 博士

【摘要】 膨润土是应用领域广泛的无机矿物材料,已广泛应用到建筑、日用化工、石油化工、橡胶、塑料、土壤改良、纺织、涂料、环境保护等领域。我国的膨润土储量丰富,但其开发还仅处于初始阶段,应用领域尚未开拓。为拓宽膨润土的应用新领域,降低彩喷纸的成本,本工作对膨润土进行改性并对改性膨润土在彩喷纸涂料中的应用适性进行了研究。根据彩喷纸涂料用颜料的特性,结合膨润土的结构、特性,分别采用硫酸和二甲基二烯丙基氯化铵对钠基膨润土进行了酸化和有机化改性,获得了比表面积显著提高的酸化膨润土和具有一定的亲水亲油的有机膨润土。通过对酸化膨润土的分散性能研究表明,酸化膨润土具有较好的分散稳定性,分散后的颗粒粒径分布在0.43μm和2.09μm之间。经二甲基二烯丙基氯化铵改性的膨润土在水相中分散后的颗粒粒径分布在0.43-2.5μm;在有机相分散获得凝胶胶体率为7.8%。说明有机膨润土具有一定的亲水和亲油性。采用SEM、XRD、化学组成分析、FTIR和TAG-SDTA对改性前后的膨润土进行了表征。XRD分析表明,酸化膨润土的层间距变大,说明层间部分离子被交换出来;经二甲基二烯丙基氯化铵有机化处理后的膨润土层间距也稍微增大,表明有机基团进入膨润土的层间。同时,改性后的酸化膨润土和有机膨润土保持了钠基膨润土的完整的体相结构。FTIR分析也确证了酸化膨润土的体相结构未发生改变。而二甲基二烯丙基氯化铵改性膨润土的热分解和FTIR分析表明,有机改性剂已覆盖在膨润土表面或插层进入膨润土片层间,说明膨润土的有机改性获得成功。SEM分析表明酸化膨润土的比表面积明显增大,并通过测定化学组成的变化分析了比表面积增大的原因。通过测定接触角,计算结果表明有机改性后的膨润土表面能下降,极性分量值降低。颜料分散液的流变行为对涂料的性质具有非常重要的影响。将酸化膨润土分散在水相中,对分散体系的浓度、分散剂用量、pH和盐浓度对酸化膨润土分散液流变行为的影响进行了探讨。在低剪切速率下,除了添加0.4%聚丙烯酸钠的分散液,各酸化膨润土分散体系流变行为均表现为剪切变稀到剪切增稠的过程,体系呈现假塑型流体到胀流型流体的变化特征。而添加0.4%聚丙烯酸钠的体系在所测的剪切速率范围内始终呈现出剪切增稠现象,表现为胀流型流体。在相同剪切速率下含0.4%分散剂体系的表观粘度最低,屈服应力最低,这表明该分散体系内的颗粒间的联接松散,分散效果好。在高剪切速率的条件下,大部分分散体系的流变特征均表现出与低剪切速率下相同的流变特性。但添加0.4%分散剂的酸化膨润土分散体系表现出的是由假塑型流体到胀流型的流体变化特征,而非低剪切速率下始终表现为胀流型的流体特征。所有分散体系与Herschel–Bulkle模型得到很好的拟合。含改性膨润土颜料的纸张涂料的稳态剪切实验表明,在低剪切速率和高剪切速率下,含改性膨润土颜料的纸张涂料均表现出剪切稀化的特性,属假塑性流体。添加酸化膨润土,涂料的粘度明显降低,因此在涂料中添加酸化膨润土可提高涂料的固含量。D改性膨润土在剪切作用下对涂料的流变有促进作用。涂料的动态应变扫描结果表明,不含酸化膨润土颜料的纸张涂料的线性粘弹性临界应变值为1.2%左右;而含酸化膨润土颜料的纸张涂料的临界应变值小于0.1%。纸张涂料动态频率扫描显示,涂料的粘弹性随着酸化膨润土用量的增加而降低;含改性膨润土涂料的相位角δ均小于45°,相位角正切值也都在小于1的范围内,涂料表现出了弹性大于粘性的特征。相对而言,含D改性膨润土的涂料相位角正切值都小于0.6的范围内,表现出较强的固体弹性特。以酸化膨润土替代部分二氧化硅加入到彩喷纸涂料中,能够提高纸张的光泽度和平滑度,降低了纸张的白度、不透明度、油墨吸收性和表面强度。含20%酸化膨润土的纸样色密度和色彩还原性能稍高于纯二氧化硅的纸样,但酸化膨润土颜料高于20%配比,色密度和色彩还原性降低。因此在涂料配方中应适当调整酸化膨润土颜料配比,改善彩喷纸的性能。含酸化膨润土的彩喷纸均表现出良好的防洇渗的性能。将DADMAC改性膨润土添加到涂料中,彩喷纸的白度、不透明度和油墨吸收性下降。光泽度、平滑度和表面强度升高。印刷色密度和色彩还原性能都随DADMAC改性膨润土的加入有所改善。更多还原

【Abstract】 Bentonite, which is rich in resources and wide application, is a inorganic mineral material. The using range of it has been extended into many fields, including building, chemical, oil, rubber, plastics, soil, textile, coating, environment industry.But the development of bentonite has still been primary stage.The scope of using bentonite does not open. In order to open new application and reduce the cost of color ink jet paper, the efforts were taken to modification of bentonite and using it in the coating of color ink-jet paper in this paper. Firstly, the modification and dispersion process of bentonite were investigated. Secondly, the effect of modified bentonite on the coating rheological behavior and paper properties were systematically studied, simultaneously.According to the characteristics of pigment used in color ink-jet paper coating, combining the structure and properties of bentonite, Na-bentonite was modified with sulfuric and dially dimethy ammonium chloride,respectively. The results showed that the specific surface ares of acid- bentonite enhanced sharply and organic bentonite is oleophilic. The study on dispersion characteristics of modified bentonite showed that acid-bentonite had better dispersion and stabilization. After modified bentonite dispersed in water, the particles size distribution of acid bentonite was mainly between 0.43μm and 2.09μm, the organic bentonite was 0.43-2.5μm, while gel level of organic bentonite dispersed in organic phases was 7.8%.The modified and unmodified bentonite were characterized by SEM, XRD, analysis of chemical composition, FTIR and TGA-SDTA techniques. Through XRD, it was found that the layer space of acid bentonite increased, which was the result that the cation in the layer was exchanged. The layer space of organic bentonite increased, too. It showed that chemical agent was inserted in the layer. The modified bentonite keeped the same structure as Na-bentonite. FTIR analysis also confirmed the same result. The themeral and FTIR analysis of organic bentontie showed the organic agent coveded the surface and inserted layer of bentonite. It meant that the modification raction succeed. SEM image showed the specific surface ares of acid bentonite enhanced sharply, this was explained by change of chemical composition. Through determining contact angle and calculating surface energy, it showed surface energy and polar components of organic bentonite decreased.The rheological behavior of pigment diapersion have important infulance on the characteristics of coating. The effect of dispersion concentration, diapersant dosage, pH and salt concentration on rheological behavior of acid bentonite were studied. At low shear rate, all of dispersion system exhibited the behavior that changed form pseudoplastic to dilatant fluid except the dispersion containing 0.4% polyacrylate sodium. The dispersion containing 0.4% polyacrylate sodium lasted the behavior of dilatant fluid, characterized as shear thickening, and exhibited the lowest apparence viscosity and yield stress, which showed that this system had good dispersing result. At high shear rate, most of dispersion exhibited the same rheological behavior as it at low shear rate. But the dispersion containing 0.4% polyacrylate sodium showed the behavior changing from pseudoplastic to dilatant fluid unlike the rheological behavior at low shear rate. All of curves of dispersion well fitted the Herschel–Bulkle model.Color ink-jet paper coatings containing various amount of modified bentonite were prepared and the coating rheological behavior were discussed. The steady rheological results showed, at low shear rate, the paper coatings cotaining modified bentonite exhibited the behavior of pseudoplastic fluid, characterized as shear thinning. The flow properties of paper coating at high shear rate was similar to flow behavior at low shear rate. It was obviously increased the solid content of coating by additiving acid bentonie. The bentonite modified with DADMAC could promote the rheological behavior of coating. The results obtained from dynamic viscoelasticity experiment revealed that the critical strain of paper coatings not containing acid bentonite was about 1.2%, while the critical strain of paper coatings containing acid bentonite was less than 0.1%. Comparatively, the dynamic elastic storage modulus and viscid loss modulus of paper coatings decreased with increasing acid bentonite content. The phase angle (δ) of paper coating containing acid bentonite were below 45°, and value of tanδwere not over 1. In brief, all of paper coatings belonged to a viscoelastic solid. The paper coating containing organic bentonite, which the tanδwas less than 0.6, showed the property of strong viscoelastic solid.The color ink-jet paper coating containing acid-bentonite, which substituted for parts of SiO2 as pigment, could improve the glossy and smoothness, but lower whiteness, opacity, ink absorption and surface strength of coated paper. The ink density and Lab value of ink-jet paper containing 20% acid-bentonite were higher than the sample containing pure SiO2,both of ink density and Lab decreased in case the coating containing over 20% acid-bentonite . So the content of acid-bentonite in coating must to be adjusted to impeove the properities of paper. The color ink-jer paper containing acid-bentonite showed the minimizing bleeding and wicking.The color ink-jet paper coating containing bentonite modified with DADMAC, could lower the whiteness, opacity and ink absorption of coated paper, but improved the glossy, smoothness and surface strength. The ink density and Lab value of ink-jet paper were improved with bentonite modified with DADMAC.更多还原