表面活性剂对水性油墨胶体稳定性的影响

对阳离子、阴离子、两性和非离子表面活性剂对水性油墨胶体稳定性的影响进行了探讨。结果表明:(1)在水性油墨胶体溶液中加入十六烷基三甲基溴化铵(CTAB)浓度为0.14 mmol/L时,Zeta电位由初始的-37.9 mV变为12.7 mV;当CTAB浓度为0.86 mmol/L时,Zeta电位上升到34.1 mV。pH对CTAB的作用效果有较大影响,当CTAB浓度为0.5 mmol/L时,将体系pH从初始值3.3调节至11.7,Zeta电位相应地从38.6 mV降至23.7 mV,炭黑粒子的平均粒径最大增加值达13 nm。(2)加入十二烷基磺酸钠(SDS)的浓度为1 mmol/L时,Zeta电位达到-38.2 mV,而炭黑粒子的平均粒径下降了2 nm。(3)加入椰油酰胺丙基氧化胺(CAPO)的浓度为0.01 mol/L时,Zeta电位在体系pH约为6.0时达到等电点;体系pH为3.2时,Zeta电位达到最大值28.5 mV,炭黑粒子平均粒径最大增加幅度为9 nm。(4)加入脂肪醇聚氧乙烯(7)醚(AEO-7)的浓度为0.1 mol/L时,体系Zeta电位从-37.9 mV变为-16.3 mV,炭黑粒子平均粒径从初始的154 nm增至240 nm。加入AEO-9得到与AEO-7相同的影响趋势。

Effects of Surfactants on the Colloid Stability of Water-based Inks

The effects of cationic,anionic,amphoteric and nonionic surfactants on the colloid stability of water-based inks were studied.(1)Zeta-potential of the ink particles reached 12.7 mV and 34.1 mV in the presence of 0.14 mmol/L and 0.86 mmol/L hexadecyltrimethylammonium bromide(CTAB),respectively.The pH level obviously affected the adsorption of CTAB on the ink particles.Zeta potential decreased from 38.6 mV to 23.7 mV over a pH range of 3.3 to 11.7 in the presence of 0.5 mmol/L CTAB and the average size of ink particles increased by 13 nm.(2)Zeta-potential could reach-38.2 mV and the particle size decreased by 2 nm on adding 1 mmol/L sodium dodecylsulfonate(SDS).(3)Zeta potential of ink particles reached the point of zero charge(PZC) at a pH of about 6.0 and it reached 28.5 mV at a pH of 3.2 in the presence of 0.01 mol/L cocamidopropylamine oxide(CAPO).The average size of ink particles increased by 9 nm with the addition of CAPO.(4)Zeta potential reached-16.3 mV and the average size increased from 154 nm to 240 nm with the addition of 0.1 mol/L alcohol ethoxylate with an ethoxylation number of 7(AEO-7).Addition of AEO-9 achieved the same effect as with AEO-7.