Research On Organic Polymer/SiO₂ Organic-inorganic Hybrid Materials

Organic-inorganic hybrid material is an even multiphase material with the advantage properties over organic and inorganic polymers. This hybrid material can be ranged from organic polymer modified by inorganic substance to inorganic glass modified by organic substance, and the properties of material are able to be tailored and constructed by adjusting the component and ratio of organic and inorganic phase. In this paper, a series of organic polymer/SiO₂ organic-inorganic hybrid materials were prepared with tetraethoxysilane (TEOS) as silica source, moreover, the preparation principle, hybrid and polymerization mechanisms, structures and properties of the organic polymer/SiO₂ organic-inorganic hybrid materials were investigated.1. Based on sol-gel method, using TEOS as silica source to hybridize with poly (2-hydroxy propylmethacrylate) (HPMA) before the polymerization of HPMA, the bulk poly (2-hydroxy propylmethacrylate) (PHPMA)/SiO₂ organic-inorganic hybrid material bonded by covalents was prepared in fully transparent homogeneous form. This method is the simplest method to prepare organic-inorganic hybrid material bonded by covalents and will have important references on the preparation of the similar organic-inorganic hybrid materials.HPMA and TEOS could be hybridized and reacted completely by step polycondensation between the hydroxyl group of HPMA and ethoxyl group of TEOS. The organic-inorganic network in the hybrid material was formed by Si-O-C chains. This PHPMA/SiO₂ organic-inorganic hybrid material possesses advantage thermal properties and can be used even at about 350℃, implying good application future.2. Based on two-step method and using TEOS as silica source, the poly 2-hydroxy propylmethacrylate-methyl methacrylate (PHPMA-MMA)/SiO₂ hybrid sol was prepared by the hybrid reaction among the silica sol, HPMA and MMA at first, then the hybrid sol was used to synthesize polyamide-6(PA6)/SiO₂ organic-inorganic hybrid materials via blending method. No other reports were found about this two-step method to prepare PA6/SiO₂ organic-inorganic hybrid material. This research result will provide a new method for preparing organic-inorganic hybrid material and a new way for reinforcing and toughening polymer.The material used to modify PA6 is PHPMA-MMA/SiO₂ hybrid sol and not traditional nano-inorganic particles. The stable organic-inorganic hybrid network dispersed by nano-SiO₂ particles have been formed in the hybrid sol, and the SiO₂ inorganic dispersion phase and the organic component were bonded by covalents. The covalents among PMMA and SiO₂ inorganic dispersion phase fixe the nano-SiO₂ particles in the organic-inorganic hybrid network, so the assembling phenomena of nano-SiO₂ particles can be avoided and this characteristic structure can limit the nano-SiO₂ particle size when blended with PA6 matrix. Moreover, nano-SiO₂ particles and PA6 matrix are bonded by hydrogen bonds directly or covalents indirectly in PA6/SiO₂ organic-inorganic hybrid material.It was found that PHPMA-MMA/SiO₂ organic-inorganic hybrid material could induce PA6 to transit from α to γ crystal form, and when the content of SiO₂ was approximately 3 wt% or more, PA6 was...