原位聚合法制备空气微胶囊及其在轻型纸中的应用

Synthesis of Air-filled Microcapsules by in-situ Polymerization and Its Application in Bulky Paper

关键词:  原位聚合  空气微胶囊  MF  轻型纸

Key Words:in-situ polymerization  air-filled microcapsule  MF  bulky paper

摘要:以三聚氰胺甲醛树脂（MF）为微胶囊壁材、空气为芯材、十二烷基硫酸钠（SDS）为乳化剂，利用原位聚合法合成了空气微胶囊，并将其作为填料制备轻型纸。实验探讨了聚合温度、乳化剂用量、搅拌速度、三聚氰胺甲醛树脂预聚体溶液用量以及pH值对微胶囊合成的影响。结果表明，微胶囊合成的最佳条件为：聚合温度55℃，转速1400 r/min，质量分数为22.7%的MF预聚体溶液用量9 mL，十二烷基硫酸钠质量分数0.2%，pH值4.0。最佳条件下得到的微胶囊经扫描电子显微镜（SEM）、傅里叶变换红外光谱仪（FT-IR）、抗压强度测试和堆积密度分析得出其形貌为空芯球形，平均粒径为8.39 μm，MF壁材聚合完全，耐压强度为0.52 MPa，堆积密度为0.05 g/cm³。所制备的微胶囊通过浆内加填的方式用于轻型纸制备，加填量为20%时，轻型纸的松厚度较空白样提高了22.15%，白度提升了7.86%，抗张强度有所下降但优于硅藻土加填轻型纸，耐破度与空白样相近。

Abstract:Air-filled microcapsules were synthesized by in-situ polymerization using a melamine-formaldehyde (MF) resin as shell and air as core of the microcapsules, sodium dodecyl sulfate (SDS) as emulsifier. The effects of temperature, amount of emulsifier, stirring speed, amount of melamine formaldehyde resin prepolymer and pH value on the synthesis of the microcapsules were investigated. The results showed that the desired microcapsules were obtained under the following conditions : dosage of MF resin prepolymer solution 9 mL(with a mass fraction of 22.7% ), sodium dodecyl sulfate concentration 0.2%, polymerization temperture 55℃, stirring speed 1400 r/min and pH value 4.0. The microcapsules obtained under the optimal conditions were analyzed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), compression strength test and bulk density test. The results showed that the morphology of the microcapsules was hollow spherical, with an average particle size of 8.39 μm. The synthesis of wall material was completed, the compression strength was 0.52 MPa, and the bulk density was 0.05 g/cm³. The synthetic air-filled microcapsules were used to prepare bulky paper by adding to the pulp, the bulk and the whiteness of the paper increased respectively by 22.15% and 7.86% compared with the control samples. The tensile strength was lower than that of the blank paper, but better than that of the bulky paper adding the diatomaceous earth, and the bursting strength was similar to that of the blank paper.