The Storage Stability Of Organic / Inorganic Hybrid Polymer Preparation And Light-cured Coatings

Sol-gel method is presently one of the main preparation methods of organic-inorganic hybrid polymers.Light-cured organic/inorganic hybrid polymers are synthesized from their surface chemical reactions of organic functional groups or functional modifications for the introduction of light-curing groups.Coating composition with organic/inorganic hybrid polymers are obtained from light-cured organic/inorganic hybrid polymers which are mixed with light-cured prepolymers and reactive monomers.It has the advantages of fast curing rate,friendly environment,being suited for thermal sensitive substrate,and so forth. It greatly enriches the performance of light-cured paint coating.But,the storage stability of light-cured organic/inorganic hybrid polymers at room temperature can not meet the basic requirements for the coatings industry, affecting a wide range of applications of such coatings.Based on the sol-gel method which is based on the basic characteristics of the chemical reaction, colloidal stability of theoretical models and previous work in the sol surface modification which has been achieved, It is thought that affecting the storage stability of light-cured particles is mainly due to the slow hydrolysis-condensation reaction which does not stop in the sol system,eventually leading to gel phenomenon. This design of the preparation of organic/inorganic hybrid polymers in this study is to add a composite of the "inhibitor gel" to increase the surface charge of particles and form a double electron layer,so that the particles keep isolated state and anti-coagulation gel process. Meanwhile, the "gel inhibitor" is also involved in light-cured film to reduce the adverse effects on membrane performance.This study includes the following two aspects:To the first part,tetraetyl orthosilicate(TEOS) and 3-trimethoxysilyl-propy-methacrylate(A174) were hydrolyzed and condened as the precursor in the presence of self-made"gel inhibitor". Silicon sols were surface-modified by 2-hydroxyethyl acrylate (HEA). The preparation of UV curable stable silicon sols were obtained. The experiment result showed that the preparation of stable silicon sols in the presence of self-made"gel inhibitor" were airtightly stored for over 28 days in the 60℃drying cabinet and in dark place for over 90 days at room temperature, viscosity of silicon sols were stable and no gel was found. It could meet the minimum requirements of storage stability of light-cured coating materials; The TEM examination showed that the preparation of stable silicon sols included micro-sized agglomeration particles and nano-sized particles.Nano-particles showed a core-shell structure,and the measured particle size of SiO2 was 50-400 nm; The cured film of the composition was prepared which the sols were mixed with six functionality polyurethane acrylate(7600) and dipentaerythritol hexaacrylate (DPHA).The properties of cured film showed modified silicon sols which included nano-sized particles could significantly improve the flexibility, adhesion and hardness of film.To the second part, polysiloxane urethane acrylate(Si-PUA) was prepared from 2-hydroxyethyl acrylate(HEA),N-ethyl-2-methyl-3-(trimethoxysilyl)-1-propanamine (A-Link 15) and isophorone diisocyanate(IPDI).Using acidic katalyst, tetraetyl orthosilicate and polysiloxane urethane acrylate were hydrolyzed and condened as the precursor in the presence of self-made"gel inhibitor".The preparation of UV curable stable organic silicone/SiO2 sols were obtained. The experiment result showed that the preparation of stable organic silicone/SiO2 sols in the presence of self-made"gel inhibitor" were airtightly stored for over 28 days in the 60℃drying cabinet and in dark place for over 90 days at room temperature, viscosity of organic silicone/SiO2 sols was stable and no gel was found.The preparation method had some versatility.The cured film of the composition was prepared which the sols were mixed with bisphenol A epoxy acrylate resin(9104).The properties of cured film showed modified silicon sols could significantly improve the flexibility, adhesion and hardness of film.With the content of silicone/SiO2 sols increased, the overall performance of film would increase at first and then decline.When the content of silicone/SiO2 sols. Adhesion, pendulum hardness, flexibility and impact strength of film were best. Thermal property of film had also been improved.