Encapsulation Of Nanometer Zinc Oxide With Poly Acetate By In-situ Polymerization

Compared with common zinc oxide(ZnO),nanometer zinc oxide(nano-ZnO) has many particular properties,due to the nanometer size effect,surface effect and strong interaction between nanometer particles and interface of polymer matrix. However,the surface molecules of nanometer particles,which have high surface activities,can integrate other molecules and aggregate easily.The size of the aggregation is far beyond the nanometer size,therefore the effects of nanometer size are gone and the propertises of products are influenced.How to solve the problem of aggregation and dispersion of nanometer particles is the key point for nanometer products.In recent decades,the encapsulation of nanometer particle by polymer,to improve the dispersion of nanometer particles in polymer matrix and the interracial adhesion between the inorganic particles and polymer.Since poly vinyl acetate(PVAc) is colorless,transparent and thermoplastic,it is used as raw material of bond,water-dope and fibers,but also used for environment-protecting construction dope.The dispersion of nano-ZnO in PVAc can help to improve anti-ageing effect of new dopes.Nanometer inorganic particles have been widely used in the modification of polymer materials.However,it is difficult to achieve a homogeneous dispersion of nanometer particles in the polymer matrix due to the great surface energy and the great polarity difference between the inorganic particles and the polymer.According to the problem mentioned above,the preparation of ZnO/PVAc was carried out.Firstly,nano-ZnO sol was prepared by sol-gel method; secondly,after the dispersion of nano-ZnO in VAc monomer,the encapsulation of nano-ZnO by PVAc(ZnO/PVAc) was prepared by in-situ polymerization.The main work are as follows:(1) By controlling the conditions of the reactions,nano- ZnO sol with small size and good dispersion was prepared by sol-gel precursOr method.According to effects of different conditions,the optimum conditions for the preparation of nano-ZnO were found;(2) The properties of nano-ZnO were certified by means of SEM and XRD and series of devicing equipments;(3) ZnO/PVAc was prepared by in-situ emulsion polymerization.According to effects of different conditions,such as,the temperature of polymerization,the amount of emulsifier,initiator and ZnO,etc.The optimum conditions for the preparation of ZnO/PVAc were found;(4) The properties of ZnO/PVAc were certified by means of SEM and TEM and series devicing equipments.Our conclusions are as follows:(1) The optimum conditions for the preparation of nano-ZnO were found,and they were:the molar ratio of ammonia to raw ZnO was 1.75:1;0.2mL water was added into every milliliter ZnO sol;the mass ratio of composite surfactant X to raw ZnO was 7:100;the temperature and time during the process of adding ammonia were -10℃and 45-60min;(2) The properties of nano-ZnO were certified by means of SEM and XRD and series of devicing equipments,and nano-ZnO powder with average diameter of 53nm by volumn was prepared;(3) The encapsulation of nano-ZnO by PVAc(ZnO/PVAc) was prepared,and the reaction conditions were discussed.The optimum conditions for the preparation of ZnO/PVAc were found,they were:nano- ZnO was firstly vibrated by ultrasonic and then added into the monomer;the mass ratio of ZnO,initiator,PVA,OP-10,water to VAc monomer were 50:100,0.8:100,10:100,1:100,120:100 respectively;(4) The properties of ZnO/PVAc were certified by means of TEM and Ultrviolate spectrum and series devicing equipments,the diameters of ZnO/PVAc latex and nano-ZnO inside were 0.3μm and 35nm.Compared to common PVAc latex,the ZnO/PVAc latex had more excellent propertises of water-fast and anti-ultraviolet.