Preparation Of APTES-NCC/AESO Pickering Emulsion And Study On Improving Paper Water Vapor Barrier

Paper-based materials have excellent mechanical properties,renewable and degradable properties,and are currently an important packaging material that is widely used.However,traditional paper has poor water vapor barrier properties,and it is difficult to meet the special requirements of high barrier properties in packaging.Based on the concept of sustainable development,it is necessary to develop a new method that by using eco-friendly materials through simple coating process can improve the water vapor barrier properties of paper.This research aims to improve the water vapor barrier properties of paper,using APTES-modified nanocrystalline cellulose（APTES-NCC）and degradable epoxy soybean oil acrylate（AESO）as raw materials,based on Pickering emulsion technology to prepare water based APTES-NCC/AESO emulsion polymerization system.APTES-NCC/AESO emulsion was implemented as barrier coating on the surface of corrugated paper to explore the effect and mechanism in improving the water vapor barrier properties of paper,providing theoretical basis and application reference for the development of new paper-based packaging materials.The research content and results are as follows:（1）Preparation and performance study of APTES modified nanocrystalline cellulose:Using APTES as modifier,NCC was modified under acidic conditions.FTIR,NMR,elemental analysis results show that–NH₂ has been successfully grafted on the surface of NCC.Compared with NCC,the surface wettability of APTES-NCC has changed significantly,the contact angle increased from25.0±0.3°to 52.2±0.4°;the surface tension of the suspension decreased from58.1±1.2 m N/m to 54.0±1.4 m N/m.AFM and TEM results showed that the morphology and size of NCC modified by APTES did not change significantly;TG results showed that the thermal stability of APTES-NCC increased.（2）Study on the emulsification stabilization effect of APTES-NCC on AESO:A stable O/W type Pickering emulsion was prepared with AESO as the oil phase and APTES-NCC as the solid particle stabilizer.The focus is on the influence of the APTES-NCC particle concentration and oil phase mass fraction on the stability,phase transition,microscopic morphology and rheological behavior of Pickering emulsion,and the stable O/W emulsion preparation condition is determined as oil phase mass fraction≤10 wt%,APTES-NCC particle concentration≥0.5 wt%.（3）Research on the application and performance of Pickering emulsion on paper surface:The effect of oil phase mass fraction on emulsion stability and paper water vapor transmission rate（WVTR）was investigated.When the concentration of APTES-NCC was 0.5 wt%,and the oil phase mass fraction is10 wt%,the prepared emulsions have good stability and hydrophobic barrier properties.The performance changes of NCC/AESO emulsion and APTES-NCC/AESO emulsion under optimal preparation conditions were discussed.Through characterization and analysis of microscopic morphology,rheological behavior,and thermal stability,the results show that the stability of APTES-NCC/AESO emulsion is higher than that of NCC/AESO emulsion under the same conditions.The changes of the surface morphology,wettability,moisture permeability and mechanical properties of the two emulsions coated with different coating amounts were compared.The results showed that as the coating amount increased,the paper surface became smoother,the water vapor transmission rate decreased significantly,and the tensile strength and elastic modulus did not change much.