【作者】 顾瑶；

【导师】 谢毅； 陈明清；

【作者基本信息】 江南大学 ， 材料学， 2012， 硕士

【摘要】 本文首先以无皂乳液聚合制得的共聚物微球聚(苯乙烯-甲基丙烯酸) P(St-MAA)为模板,γ-氨丙基三甲氧基硅烷(APS)为助结构导向剂,正硅酸四乙酯(TEOS)为硅源,制备了P(St-MAA)/SiO2复合微球,通过煅烧处理除去有机模板得到了中空二氧化硅微球。通过控制共聚体系中苯乙烯的用量可调节共聚物微球的尺寸,进而改变中空二氧化硅微球的尺寸及壳层的孔结构。分别采用傅里叶变换红外光谱(FTIR)、激光光散射仪(LLS)、热重分析仪(TG)、透射电子显微镜(TEM)和比表面积及孔径分析仪分析了共聚物模板、复合微球及中空二氧化硅的结构、粒径及分布、热分解温度、形态和孔结构。所得结果表明:通过调节共聚物模板的粒径可将中空微球的尺寸控制在140-630nm,且壳层中具有丰富的孔结构。以十二烷基苯磺酸钠(SDBS)为乳化剂,过硫酸铵(APS)作为引发剂,采用种子乳液聚合法制得了聚(苯乙烯-丙烯酸乙酯-甲基丙烯酸) P(St-EA-MAA)三元共聚物微球,通过改变单体甲基丙烯酸的用量,在不同温度及pH条件下对所得共聚物微球进行热处理,在包覆二氧化硅的过程中,分别调节体系pH值和加入一定量的阳离子型表面活性剂十六烷基三甲基溴化铵(CTAB),考察对中空二氧化硅结构与形态的影响。分别利用FTIR、Zeta电位仪、TEM、TG和比表面积及孔径分析仪对共聚物模板、复合微球和中空二氧化硅的结构、表面-COOH含量、形态、热分解温度以及壳层孔结构进行了表征,结果显示:改变单体甲基丙烯酸的用量可调节共聚物微球表面的-COOH含量,从而控制中空二氧化硅壳层中的孔径由微孔向介孔转变,并可以显著增大中空二氧化硅微球的比表面积;在不同温度及pH条件下对共聚物微球进行热处理,可改变模板的形态,制得了不同形貌的中空二氧化硅;在包覆二氧化硅的过程中,调节体系pH值可以控制所得中空二氧化硅微球的壁厚,加入一定量的CTAB可以更显著增加中空微球的壁厚,使其结构更加稳定,并在壁层中引入了介孔结构,增大了比表面积。将制备的大小、壁厚适中,结构稳定,分散性良好的中空二氧化硅微球与水性聚氨酯共混制备了水性分散涂料,并探讨了中空二氧化硅微球掺杂量和涂膜组成对涂料保温性能的影响,实验发现在涂膜组成适宜且中空二氧化硅微球的掺杂量适中的情况下可以制得具有较好保温性能的涂料,因而中空二氧化硅在保温涂料领域具有潜在的应用价值。更多还原

【Abstract】 P(St-MAA) copolymer microspheres were synthesized by soap-free emulsion polymerization using styrene (St) and methylacrylic acid (MAA) as monomers in this paper. The P(St-MAA)/SiO2 composite microspheres were prepared by using coupling agentγ- aminopropyltrimethoxysilane (APS) and tetraethyl orthosilicate (TEOS) as costructure- directing agent and silicon sources in the presence of the P(St-MAA) microspheres as template, hollow silica microspheres were obtained by removing the P(St-MAA) templates based on calcination. The diameter of the copolymer microspheres can be adjusted by the content of styrene, the size of hollow silica and the pore structure of shell can be changed simultaneously. The properties of the copolymer microspheres, composite microphere and hollow silica, such as structures, diameter and diameter distribution, thermal decomposition temperature, morphologies and pore structure were characterized by Fourier transformation infrared (FTIR), laser light scattering (LLS), thermogravimetric analyzer (TGA), transmission electron microscopy (TEM) and specific surface area and pore size analyzer separately. The results showed that the diameter of hollow silica microspheres can be controlled in 140-630nm by adjusted the size of the P(St-MAA) microspheres, and the shell of hollow silica is rich of pores.P(St-EA-MAA) copolymer microspheres were synthesized by seed emulsion polymerization of styrene (St), ethylacrylate ester (EA) with methacrylic acid (MAA) using sodium dodecyl benzene sulfonate (SDBS) as emulsifier, ammonium persulfate as initiator. The copolymer microspheres can be modified by changing the amount of MAA, heat treatment under different pH values and temperatures, adjusting the pH value and adding surfactant cetyltrimethyl ammonium bromide (CTAB). The properties of the copolymer microspheres, composite microspheres and hollow silica, such as structures, -COOH content, morphologies, thermal decomposition temperature and pore structure were characterized by FTIR, Zeta potential analyzer, TEM, TGA and specific surface area and pore size analyzer separately. The results showed that the -COOH content on the surface of copolymer microspheres can be adjusted by changing the amount of MAA, than the pore size of shell can be changed from microporous to mesoporous and the specific surface area of hollow silica microsphere can be significantly increased. The shape of P(St-EA-MAA) microspheres can be changed by the heat treatment under different pH values and temperatures, then the morphology of hollow silica can be changed also. In the process of silica coating, hollow silica shell thickness can be adjusted by the pH value, and the introduction of CTAB can significantly increase the shell thickness of hollow microspheres which makes the structure more stability, and introduced mesoporous into the shell, so the specific surface area was increased.Polyurethane aqueous dispersion coating was prepared as follows: the hollow silica which size, shell thickness is moderate, structural is stability, dispersion is good were blending with polyurethane. The effect of hollow silica microsphere dope content and the coating composition on coating thermal insulating was discussed. The results showed that coatings with good insulation properties can be obtained when the composition of coating is suitable and the hollow silica microspheres doped is moderate, which also have a potential application in the insulating coatings field.更多还原