【作者】 全凤玉；

【导师】 夏延致；

【作者基本信息】 青岛大学 ， 材料学， 2009， 博士

【摘要】 高分子互穿网络特别是有机/无机高分子互穿网络材料,由于其独特的结构性能已经引起人们广泛的研究兴趣,是目前高分子材料研究领域的热点之一。它部分克服了单一材料和传统复合材料性能的缺陷,使材料既具有无机材料的优点（如刚性、高热稳定性）,又具有高分子材料的优点（如弹性、介电性、延展性和可加工性等）,并且由于两组分之间形成互穿网络结构而产生额外的性能提高。本论文采用溶胶凝胶法,分别采用硅酸钠、正硅酸乙酯为二氧化硅前躯体（二氧化硅以聚硅酸的形式存在）,以纤维素、聚乙烯醇、海藻酸为有机基体,制备出一系列有机/无机高分子复合材料,并研究它们的结构与性能之间的关系。1)采用溶胶凝胶法以正硅酸乙酯为无机前驱体,制备出聚乙烯醇/SiO₂具有部分互穿网络特征膜及纤维。通过FTIR、²⁹Si NMR测试表明,PVA大分子与聚硅酸大分子之间形成了具有双相连续的互穿网络特征的复合材料;通过TEM、AFM测试表明,随着无机相含量的增加,有机相与无机相之间越易形成网络结构,且随着无机相含量增加,有机相与无机相的相容性提高。通过DSC、TG测试表明,无机相的加入和部分互穿网络的形成,提高了PVA大分子的热稳定性。聚乙烯醇/SiO₂混合溶液的纺丝性能优于纯PVA溶液,纺丝温度下降,可纺温度范围变宽,工业化生产可大大节约成本。通过SEM、TEM观察无机粒子在纤维中的分布情况,PVA/SiO₂复合纤维表面含有部分SiO₂,而随着无机相加入量的增加,纤维内部聚硅酸形成网状结构与PVA大分子表成互穿结构。通过TG及DTG表明聚硅酸的加入增强了PVA的热稳定性能。采用极限氧指数法LOI、锥形量热法CONE测定燃烧性能,聚硅酸的加入能有效提高PVA的阻燃性能。2)采用溶胶凝胶法以硅酸钠为无机前驱体,制备出纤维素/SiO₂复合纤维。通过FTIR、TEM分析表明,硅酸钠水解后形成聚硅酸,聚硅酸是一种网络状大分子与纤维素大分子间形成细胞互穿网络结构,纤维素大分子与无机大分子相容性好,使纤维同时具有有机材料与无机材料的优良性能。采用裂解-气相色谱-质谱测试对纤维素纤维的燃烧机理进行了研究,纤维素/SiO₂复合纤维中的聚硅酸与纤维素大分子链之间的互穿与交联,减少了热解过程中左旋葡聚糖及乙醇醛的生成,从而减少可燃性小分子的生成。同时燃烧过程中聚硅酸在纤维表面形成一层二氧化硅,可以阻止外部热量的进入,也可以阻止裂解后产生的可燃性气体的逸出。从而提高了纤维素/SiO₂复合纤维的阻燃性能。3)采用溶胶凝胶法以硅酸钠为无机前躯体,制备了一系列的海藻酸/SiO₂复合纤维。通过FTIR、TEM分析表明,硅酸钠水解后形成聚硅酸,聚硅酸是一种网络状大分子与海藻酸大分子间形成细胞互穿网络结构。通过XRD、锥形量热法CONE对其进行初步的研究,材料的结晶度有所提高,材料的阻燃性能有所提高。更多还原

【Abstract】 Organic/inorganic interpenetrating network（IPN） materials have extracted extensive research interests due to their unique properties.The materials combine the advantages of the inorganic materials（rigidity,high thermal stability and unique optical） and the organic polymers（flexibility,dielectric,ductility and processability）, which is different with the single material and conventional composite materials. Moreover,those materials have more capability because of special IPN structure.In the thesis,several types of organic/inorganic composites were prepared using sodium silicate,TEOS as the inorganic components and cellulose,PVA and alginate as organic compounds for different purposes.The correlation between structure and the propertied for those materials was studied.1) PVA/SiO₂ Organic-inorganic Composite materials were prepared by hydrolysis and condensation of tetraethoxysilane（TEOS） in poly（vinyl alcohol）（PVA） solution. The organic phase and inorganic phase were all continouse in the IPN.The structure and morphology of the materials were investigated by infrared spectroscopy （FTIR）,²⁹SiNMR and transmission electron microscopy（TEM）.The thermal properties were examined by thermogravimetric analysis（TGA） and differential scanning calorimetry（DSC）.FTIR spectroscopy showed the formation of Si-O-Si bonds in the system.TEM demonstrated a homogeneous dispersion of silica in the PVA matrix when the amount of TEOS added was appropriate.DSC and TGA revealed that,compared with pure PVA materials,the composite materials exhibited a higher glass transition temperature（Tg） and high thermal stability.It showed that the adding of silica reinforced thermal stability of PVA/SiO₂ composite fibers.The SiO₂ particles changed the thermal and reduced thermal degradation behaviors.The Flammability Property of fibers were exanimed by LOI and CONE.It showed that SiO₂ can improve the flame-retardant property of fibers.2) Cellulose/SiO₂ Organic/inorganic Composite fibers were prepared by an in sol-gel method.Poly（silicic-acid） extracted from sodium silicate was used as the inorganic component and cellulose was used as an organic compound.The cellutated IPN was formed.The obtained membranes were characterized by Fourier-transform infrared spectroscopy（FTIR）,Transmission electron micrograph（TEM）.The results revealed that the inorganic content in the membranes varied with the amount of sodium silicate、temperature and pH of regeneration solution.The Combustion Mechanism of Cellulose/SiO₂ Composite fibers were characterized by PY-GC-MS.It showed that the inorganic in fibers decrease the levoglucosan and hydroxyacetaldehyde, accordingly decreased small flammable molecular compounds.The SiO₂ out of fibers could prevent O₂ and flammable molecular compounds.3) Alginate/SiO₂ Organic-inorganic composite fibers were prepared by an in sol-gel method using sodium silicate and TEOS as inorganic components.The cellutated IPN was formed.The structure and morphology of the fibers were investigated by FTIR and TEM.The crystallinity was examined by XRD.The FTIR spectroscopy showed the formation of Si-O-Si bonds in the system.TEM demonstrated a homogeneous dispersion of silica in the alginate matrix.The crystallinity was higher than alginate materials.The Flammability Property of fibers were exanimed by CONE.It showed that SiO2 can improve the flame-retardant property of fibers.更多还原