羧基化纳米纤维素乳化马来松香甘油酯乳液稳定性及超疏水纸制备

Stability of carboxylated nanocellulose emulsified maleic rosin glyceride emulsions and preparation of superhydrophobic papers

摘要:

采用溶剂助溶法制备马来松香酯乳液，确定了最佳的工艺合成条件。比较分析了十二烷基硫酸钠（SDS）、烷基酚聚氧乙烯醚（OP-10）和羧基化纳米纤维素（CNF-C）马来松香酯乳液粒径和稳定性的影响。采用双层涂布的方式，机械浆纳米纤维素和沉淀碳酸钙PCC作为第一道涂布，马来松香酯乳液作为第二道涂布，构建了超疏水性纸张的工艺策略。研究发现：马来松香酯的最佳合成工艺条件为马来松香和甘油的配比为1:3；引发剂（偶氮二异丁腈）用量为0.4%；催化剂（纳米ZnO2）用量为2%；在250℃条件下反应5小时。羧基化纳米纤维素作为乳化剂，制备的马来松香乳液粒径达到527 nm，在室温下静置90天不破乳分层，具有较强的稳定性。双层涂布制备的PCC-CNF-MAP-DG涂布纸与水的接触角159.1°，cobb值为2.4 g/m2，且经过200次折叠后仍具有超强的疏水性能，并且耐酸碱，具有良好的化学稳定性。纸张的超疏水性源于双级结构间滞留的空气对水滴的托举，在纸张纤维表面形成致密的疏水层。

Abstract:

The solvent-assisted solvent solubilisation method was used for the preparation of maleic rosin ester emulsions, and the optimum process synthesis conditions were determined. The effects of sodium dodecyl sulphate (SDS), alkylphenol polyoxyethylene ether (OP-10) and carboxylated nanofibrillated cellulose (CNF-C) on the particle size and stability of the maleic rosin ester emulsions were comparatively analysed. The process strategy for superhydrophobic paper was constructed using a two-layer coating method, with mechanically pulped nanocellulose and precipitated calcium carbonate PCC as the first coat and maleic rosin ester emulsion as the second coat. It was found that the optimal process conditions for the synthesis of maleic rosin ester were 1:3 ratio of maleic rosin and glycerol; 0.4% dosage of initiator (Azobisisobutyronitrile); 2% dosage of catalyst (nano-ZnO2); and 5 hours reaction at 250 °C. Carboxylated nanocellulose was used as the emulsifier, and the prepared maleic rosin emulsion reached a particle size of 527 nm, which was stable without emulsion breakage and delamination after 90 days of standing at room temperature. The PCC-CNF-MAP-DG coated paper prepared by double-layer coating has a contact angle of 159.1° with water, a cobb value of 2.4 g/m2, and still has super-hydrophobicity after 200 folds, as well as acid- and alkali-resistant, with good chemical stability. The super-hydrophobicity of paper originates from the hold-up of water droplets by air trapped between the two-stage structure, forming a dense hydrophobic layer on the surface of paper fibers.