接枝共聚制备阳离子硫酸盐浆

Preparation of Cationic Kraft Pulp by Grafting Copolymerization

以丙烯酰胺和甲基丙烯酰氧基乙基三甲基氯化铵与纸浆纤维接枝共聚制备了阳离子硫酸盐浆。实验结果表明,当引发剂硝酸铈铵的用量(对绝干浆)从2%提高到8%时,纸浆的接枝率和阳离子表面电荷密度稳步提高;进一步提高引发剂的用量,纸浆的接枝率和阳离子表面电荷密度变化平坦。随着反应温度的升高,纸浆的接枝率和阳离子表面电荷密度先升后降,当温度为50℃时接枝率和阳离子表面电荷密度最高。在浆浓较低时,随着浆浓的提高,接枝率和阳离子表面电荷密度提高,当浆浓超过11%时,接枝率和阳离子表面电荷密度下降。当甲基丙烯酰氧基乙基三甲基氯化铵在总单体中摩尔比例为40%～50%时表面电荷密度最高。通过红外光谱分析发现,丙烯酰胺和甲基丙烯酰氧基乙基三甲基氯化铵已成功地接枝到硫酸盐浆上。

Cationization of pulp fibres by grafting copolymerization has been regarded as one of the effective approaches to enhance the paper strength and improve the retention of fillers and fines. In this work, cationic kraft pulp was prepared by grafting copolymerization using acrylamide and cationic monomer [ 2-（methacryloyloxy） ethyl] trimethyl-ammonium chloride （MAETMAC）. The grafting rate and surface charge density of the pulp increased when the amount of cerium （ Ⅳ ） ammonium nitrate （CAN） initiator increased from 2% to 8% （ on oven dried pulp） and then levelled off when the amount of the initiator increased continuously. The grafting rate and surface charge density of the pulp were also influenced by the reaction temperature, they increased from 20℃ to 50℃ and reached the maximum value at 50℃. Preferably, the pulp consistency should not exceed 11% while the MAETMAC molar percentage on the total monomer should be maintained at 40% - 50% in order to obtain the maximum grafting rate and surface charge density. Fourier Transform Infrared Spectroscopic （FT-IR） analysis confinned the presence of the grafted copolymers on the fibre surface.