聚磷酸铵微胶囊化改性及其制备疏水阻燃纸的研究

Study on Microencapsulation of Ammonium Polyphosphate and Preparation of Hydrophobic Flame Retardant Paper

关键词:  聚磷酸铵  溶胶凝胶法  微胶囊化  阻燃  疏水

Key Words:ammonium polyphosphate  sol-gel method  microencapsulation  flame retardant  hydrophobicity

摘要:以正硅酸乙酯（TEOS）和甲基三乙氧基硅烷（MTES）为前驱体，使用溶胶凝胶法对聚磷酸铵（APP）进行微胶囊化改性，通过浆内添加法制备疏水阻燃纸。结果表明，APP为表面光滑的方形结构颗粒，具有强亲水性和负电性。在碱性条件下，TEOS和MTES共同形成致密粗糙二氧化硅壳层，将APP微胶囊化包裹。当MTES添加量为6%时，相比改性前，微胶囊化APP平均粒径由23.98 μm增至28.52 μm，水接触角从13.5°增至97.7°，由亲水性转变为疏水性，Zeta电位由-67.5 mV降至-45.8 mV，负电性减弱。与添加40%改性前APP的纸张相比，添加40%微胶囊化APP的纸张Cobb值由61.7 g/m²降至27.2 g/m²，极限氧指数（LOI）由27.1%升至31.8%，阻燃性能和疏水性能均有显著提高，达到了难燃级别。

Abstract:In this study， tetraethoxysilane （TEOS） and methyltriethoxysilane （MTES） were used as precursors to modify ammonium polyphosphate （APP） by sol-gel method， and then hydrophobic flame retardant paper was prepared by in-pulp addition method. The results showed that APP was a square particle with smooth surface and had strong hydrophilicity and electronegativity. Under alkaline condition， TEOS and MTES together formed a dense rough silica shell to encapsulate APP. When 6% MTES was added， the average particle size of the microencapsulated APP increased from 23.98 μm to 28.52 μm， the water contact angle increased from 13.5° to 97.7°， indicating that changed from hydrophilicity to hydrophobicity， and the Zeta potential decreased from -67.5 mV to -45.8 mV with the negative charge decreased. Compared with the paper with 40% APP， the Cobb value of the paper with 40 % microencapsulated APP decreased from 61.7 g/m² to 27.2 g/m²， and the limiting oxygen index （LOI） increased from 27.1% to 31.8%. The flame retardancy and hydrophobic properties were significantly improved， reaching the flame-retardant level.