溶胶凝胶法制备具有介孔结构的聚酰亚胺/SiO_2多孔复合微球
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摘要
采用反相乳液法,以水溶性聚酰胺酸三乙胺盐(PAAS)、正硅酸乙酯(TEOS)为前驱体,通过溶胶凝胶法制备了具有介孔结构的聚酰亚胺(PI)/SiO_2多孔复合微球。将PAAS水溶液和TEOS水解液的混合溶液在液体石蜡中形成反相乳液,TEOS经水解缩合形成无机三维骨架,通过化学酰亚胺化使复合体系中的PAAS转变为PI,成功制备了含有介孔结构的PI/SiO_2多孔复合微球。研究发现,随着SiO_2含量的增加,复合微球的规整性不断提高,其比表面积由20.5 m~2/g增加至521.8 m~2/g。同时发现,调节TEOS水解液的pH值,微球的比表面积也会发生相应的变化。此外,热重分析结果显示该复合微球的热分解温度超过500℃,表明其具有优异的热稳定性。
Based on the inverse emulsion with water soluble poly( amic acid) salt( PAAS),tetraethyl orthosilicate( TEOS) as precursor,polyimide( PI)/SiO_2 porous composite microspheres with mesoporous structure were prepared by sol-gel method. The mixed solution of PAAS aqueous solution and TEOS hydrolysis solution were used to form inverse emulsion in liquid paraffin,and the inorganic three-dimesional skeleton formed by hydrolysis and condensation of TEOS.After adding chemical imidization reagents,PAAS was imidized and formed PI then porous PI/SiO_2 composite microspheres with mesoporous structure were fabricated successfully. The results show that with increase of the SiO_2 content,the regularity of the composite microspheres increases,and the specific surface area increases from 20. 5 m~2/g to 521. 8m~2/g. At the same time,it is found that the specific surface area of microspheres could be changed by adjusting the pH value of TEOS hydrolysate. The TGA results show that the thermal decomposition temperature of the composite porous microspheres is more than 500 ℃,which shows that it has excellent thermal stability.
Based on the inverse emulsion with water soluble poly( amic acid) salt( PAAS),tetraethyl orthosilicate( TEOS) as precursor,polyimide( PI)/SiO_2 porous composite microspheres with mesoporous structure were prepared by sol-gel method. The mixed solution of PAAS aqueous solution and TEOS hydrolysis solution were used to form inverse emulsion in liquid paraffin,and the inorganic three-dimesional skeleton formed by hydrolysis and condensation of TEOS.After adding chemical imidization reagents,PAAS was imidized and formed PI then porous PI/SiO_2 composite microspheres with mesoporous structure were fabricated successfully. The results show that with increase of the SiO_2 content,the regularity of the composite microspheres increases,and the specific surface area increases from 20. 5 m~2/g to 521. 8m~2/g. At the same time,it is found that the specific surface area of microspheres could be changed by adjusting the pH value of TEOS hydrolysate. The TGA results show that the thermal decomposition temperature of the composite porous microspheres is more than 500 ℃,which shows that it has excellent thermal stability.
引文
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[3]Samiey B,Cheng C H,Wu J N.Organic-inorganic hybrid polymers as adsorbents for removal of heavy metal ions from solutions:a review[J].Materials,2014,7:673-726.
[4]白青龙,张春花,王冀敏.多孔材料的研究进展[J].内蒙古民族大学学报:自然科学版,2004,19(5):528-531.Bai Q L,Zhang C H,Wang J M.The recent developments in porous material[J].Journal of Inner Mongolia University for Nationalities,2004,19(5):528-531.
[5]Feng J Z,Wang X,Jiang Y G,et al.Study on thermal conductivities of aromatic polyimide aerogels[J].ACS Appl.Mater.Interfaces,2016,8:12992-12996.
[6]Huang J Y,Zheng Y X,Luo L B,et al.Facile preparation of highly hydrophilic,recyclable high-performance polyimide adsorbents for the removal of heavy metal ions[J].J.Hazard.Mater.,2016,306:210-219.
[7]Gu S l,Zhai C H,Jana S C.Aerogel microparticles from oil-in-oil emulsion systems[J].Langmuir,2016,32:5637-5645.
[8]Lai F L,Huang Y P,Zuo L Z,et al.Electrospun nanofibersupported carbon aerogelas a versatile platform toward asymmetric supercapacitors[J].J.Mater.Chem.A,2016,4:15861-15869.
[9]Wu Q,Pan L L,Wang H J,et al.A green and scalable method for producing high-performance polyimide aerogels using low-boiling-point solvents and sublimation drying[J].Polym.J.,2016,48:169-175.
[10]Yang Y,Jia Z X,Wang Y,et al.Preparation of hemispherical polyimide particles by inverse emulsion technique from poly(amic acid)ammonium salts[J].Colloid Polym.Sci.,2013,291:1049-1055.
[11]Ma L,Yang Y,He C Y,et al.In situ preparation and characterization of polyimide/silicacomposite hemispheres by inverse aqueous emulsion technique and sol-gel method[J].Colloid Polym.Sci.,2015,293:1281-1287.