原位聚合纳米SiO2法超支化CPAM的制备及其对纸张的增强作用

摘要

选用季戊四醇(PETL)为多官能团支化剂,硝酸铈铵为引发剂,甲基丙烯酰氧乙基三甲基氯化铵(DMC)为阳离子单体,与丙烯酰胺(AM)在水溶液中发生自由基反应合成支化结构的阳离子聚丙烯酰胺(BCPAM)后,再加入正硅酸乙酯(TEOS)水解原位产生纳米SiO2,在BCPAM分子中产生物理交联,制备超支化阳离子聚丙烯酰胺(SiO2-BCPAM),研究了其作为纸张增强剂对纸张的增强作用,通过红外光谱(FT-IR)和扫面电镜(SEM)对产物的结构和特性进行表征.结果表明,所合成的产物为SiO2-BCPAM杂化材料;引发剂、TEOS用量和反应时间影响SiO2-BCPAM相对分子质量或分子链的形态进而影响其特性黏度;SiO2-BCPAM对纸张增强效果明显,当其用量为0.5％(对绝干浆)时,纸张的抗张指数、耐破指数和撕裂指数比空白纸样分别提高了23.6％、12.4％和25.5％.%Branched cationic polyacrylamide (BCPAM) was synthesized via free-radical solution polymerization of acrylamide (AM) and methacrylatoethyl trimathyl ammonim chloride (DMC) (DMC) by using pentaerythritol (PETL) as the core molecule and ceric ammonium nitrate (Ce4+) as the initiator.The Nano-SiO2 was produced in BCPAM by hydrolysis of tetraethyl orthosilicate (TEOS) in situ and the resulted SiO2 interacted with BCPAM through physical crosslinking.The structure of SiO2-BCPAM was characterized by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM).The study results indicated that the initiator concentration,TEOS dosage and reaction time influenced the molecular weight or chain aggregation,and then the intrinsic viscosity.The SiO2-BCPAM exhibited significant paper strengthening performance.For instance,when the dosage of SiO2-BCPAM was 0.5％ (based on oven dried pulp),the dry tensile index,burst index and tear index of the hand sheet were increased by 23.6％,12.4％ and 25.5％ respectively.