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

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23.98μm增至28.52μm,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。

In this study,tetraethoxysilane(TEOS)and methyltriethoxysilane(MTES)were used as precursors to modify ammonium poly⁃phosphate(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 23.98μm to 28.52μm,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 de⁃creased.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.