Study On Nano Zinic Oxide Grafted Polymer Hybird Emulsion

Nano/polymer composites can be integrated nano-materials and polymer properties, which show great application potential in the fields of thermal, optical, mechanical and so on. The technique of introducing activated groups onto the surface of inorganic nano-particles to fabricate grafting typed nano/polymer composite emulsion that could enhance the compatibility of the inorganic particles and polymer and exert function of nanomaterials with polymer properties fully.Nanoparticles were modified in two different ways. Nano ZnO particles were bonded with oleic acid molecules, and the other was anchoraged 4,4'-Azobis(4-cyanovaleric acid) (ACVA) onto the surface of nano ZnO. Then grafted type and encapsulated type nano ZnO/PSt hybrid emulsion was fabricated by technology of miniemulsion polymerization.Nano-ZnO particles modified via oleic acid was achieved through esterification between carboxy group of oleic acid and hydroxyl group of ZnO.The dispersion and lipophilic of nano ZnO was strengthen, which make nano ZnO encapsulated better by PSt, because of organic groups introducted onto the surface of nano ZnO. Encapsulated type nano ZnO/PSt hybrid emulsion was fabricated by technology of miniemulsion polymerization. The result shows that hybrid emulsion has conversion rate of 86% and encapsulated efficiency of 70%, under the condition of the dosage of emulsifier Ms-1 is 2.0 g, OP-10 is 1.0 g, aid emulsifier HD is 0.6 g, AIBN and KPS mixed using(2:1) is 0.5 g, the reaction temperature is 80℃. But the graft efficiency was 31.28% lower. Therefore, initiation groups were introduced onto the surface of nano ZnO to synthesize grafted type nano ZnO/PSt hybrid emulsion.Functional modification of nano ZnO was carried out via ACVA in another method. Initiator of ACVA was anchoraged onto the surface of nano ZnO in the form of chemical bond was achieved by KH-560 as medium. The result shows that graft rate of ACVA onto surface of nano ZnO is higher, when the dosage of KH-560 is 2.0 g, ACVA is 3.0 g, the reaction temperature is 50℃, the reactionof time is 4 h. ACVA was grafted onto the surface of nano ZnO in the form of chemic bond, which mensurated via XPS, XRD and FT-IR. Grafted type nano ZnO/PSt hybrid emulsion was synthesized through technology of miniemulsion polymerization. The result shows that hybrid emulsion has conversion rate of 89% and higher graft efficiency of 90%, under the condition of ACVA-ZnO is 1.25 g, the dosage of emulsifier Ms-1 and OP-10 as composite emulsifier, hexadecane as aid emulsifier, ultrasonic power is 400 w,the reaction temperature is 75℃. Hybrid emulsion was characterized by XPS, TGA, and TEM and so on. The results show that nano ZnO combined PSt with the form of chemic bond. And the schem of synthesis of grafted type ZnO/PSt via technology of miniemulsion polymerization was studied.The application of grafted type nano ZnO/PSt of composite particles was studied, which was able to improve the properties of thermal, optical, mechanical for polymer materials. The grafted type nano ZnO/PSt composite particles can increase the softening temperature of polymer to165℃, 26.9% raised. Anti-UV performance of epoxy acrylic emulsion was strengthen evidently. The hardness of epoxy acrylic emulsion coating was increased from 0.41 H to 0.58 H. Tensile strength of PVC can reach to 81 MPa, and impact strength to 12.1 kJ/m2. Grafted type nano-ZnO/PSt composite particles have a more excellent mechanical properties, compared to encapsulated type nano ZnO/PSt composite particles.