醚基硅溶胶和多异氰酸酯反应制备SiO_2原位增强聚氨酯硬泡及其增强机理
|
摘要
应用自制界面剂控制硅溶胶粒径,得到一种以聚醚多元醇为分散介质的聚醚基硅溶胶,以此硅溶胶与多异氰酸酯(PAPI)反应,制备了二氧化硅(SiO_2)原位增强聚氨酯(PU)硬泡。通过发泡反应特性测试、电子显微镜观察泡孔结构及PU硬泡的压缩强度测试,研究了原位反应生成的SiO_2对PU泡孔结构的影响,并结合数学模拟计算结果,探讨了SiO_2对PU硬泡的增强机理。结果表明,界面剂对硅溶胶有较强稳定作用,原位反应生成的SiO_2在PU发泡过程中具有良好的异相成核作用,且这种作用导致的泡孔均匀性与泡孔壁厚增加是SiO_2增强PU硬泡的主要原因。当聚醚基硅溶胶浓度为8%时(以SiO_2含量计),制备出的PU硬泡的泡孔较均匀,压缩强度较未增强的PU硬泡提升了约50%。
A polyether-based silica sol was prepared from self-made surfactant and silica sol. This polyether-based silica sol reacted with polyisocyanate(PAPI) to prepare in-situ reinforced rigid SiO_2/PU foams. In order to study effects of SiO_2 on the cell structure of polyurethane(PU) and the reinforce mechanism, the cell structure was observed by scanning electron microscope(SEM) and a mathematical model was used. The results show that the surfactant has a strong stabilizing effect on the silica sol, and the SiO_2 made by in-situ reaction has a good heterogeneous nucleation during the PU foaming process. When the content of the polyether-based silica sol is 8%(calculated by the SiO_2 content), the prepared PU foam presents a uniform cell size distribution, and the compressive strength is increased by about 50% compared with that of the non-silica sol.
A polyether-based silica sol was prepared from self-made surfactant and silica sol. This polyether-based silica sol reacted with polyisocyanate(PAPI) to prepare in-situ reinforced rigid SiO_2/PU foams. In order to study effects of SiO_2 on the cell structure of polyurethane(PU) and the reinforce mechanism, the cell structure was observed by scanning electron microscope(SEM) and a mathematical model was used. The results show that the surfactant has a strong stabilizing effect on the silica sol, and the SiO_2 made by in-situ reaction has a good heterogeneous nucleation during the PU foaming process. When the content of the polyether-based silica sol is 8%(calculated by the SiO_2 content), the prepared PU foam presents a uniform cell size distribution, and the compressive strength is increased by about 50% compared with that of the non-silica sol.
引文
[1] Kausar A.Polyurethane composite foams in high-performance applications:a review[J].Polym.Plast.Technol.Eng.,2018,57:346-369.
[2] Verdolotti L,Lavorgna M,Lamanna R,et al.Polyurethane-silica hybrid foam by sol-gel approach:chemical and functional properties[J].Polymer,2015,56:20-28.
[3] Meegoda J N,Tantemsapya N.Microscopic modeling of colloidal silica stabilized granular contaminated soils[J].J.Mater.Civil Eng.,2007,19:91-98.
[4] Nazeran N,Moghaddas J.Synthesis and characterization of silica aerogel reinforced rigid polyurethane foam for thermal insulation application[J].J.Non-Cryst.Solids,2017,461:1-11.
[5] Shukla S,Koelling K W.Classical nucleation theory applied to homogeneous bubble nucleation in the continuous microcellular foaming of the polystyrene- CO2 system[J].Ind.Eng.Chem.Res.,2009,48:7603-7615.
[6] Andersons J,Kirpluks M,Stiebra L,et al.Anisotropy of the stiffness and strength of rigid low-density closed-cell polyisocyanurate foams[J].Mater.Des.,2016,92:836-845.
[7] Ferkl P,Kr?ková I,Kosek J.Evolution of mass distribution in walls of rigid polyurethane foams[J].Chem.Eng.Sci.,2018,176:50-58.
[8] Gibson L J,Ashby M F.Cellular solids:structure and properties[M].Cambridge:Cambridge University Press,1999.
[2] Verdolotti L,Lavorgna M,Lamanna R,et al.Polyurethane-silica hybrid foam by sol-gel approach:chemical and functional properties[J].Polymer,2015,56:20-28.
[3] Meegoda J N,Tantemsapya N.Microscopic modeling of colloidal silica stabilized granular contaminated soils[J].J.Mater.Civil Eng.,2007,19:91-98.
[4] Nazeran N,Moghaddas J.Synthesis and characterization of silica aerogel reinforced rigid polyurethane foam for thermal insulation application[J].J.Non-Cryst.Solids,2017,461:1-11.
[5] Shukla S,Koelling K W.Classical nucleation theory applied to homogeneous bubble nucleation in the continuous microcellular foaming of the polystyrene- CO2 system[J].Ind.Eng.Chem.Res.,2009,48:7603-7615.
[6] Andersons J,Kirpluks M,Stiebra L,et al.Anisotropy of the stiffness and strength of rigid low-density closed-cell polyisocyanurate foams[J].Mater.Des.,2016,92:836-845.
[7] Ferkl P,Kr?ková I,Kosek J.Evolution of mass distribution in walls of rigid polyurethane foams[J].Chem.Eng.Sci.,2018,176:50-58.
[8] Gibson L J,Ashby M F.Cellular solids:structure and properties[M].Cambridge:Cambridge University Press,1999.