Preparatio And Properties Of Nano-titanium Dioxide/Polystyrene Composite Microspheres

Nano TiO2 has good photocatalytic activity and antibacterial properties.It also has a wide application prospect.In recent years,research on titanium dioxide composites has become a hot topic.Polystyrene is a common polymer resin material with excellent processability,thermoplastic and chemical stability.At present,it is widely used in the traditional fields such as architecture,life and packaging.In addition,the functionalized polystyrene material also has been paid to the application and research such as magnetic polystyrene,nano aluminum/polystyrene,graphene/polystyrene.In this paper,the synthetic method of TiO2/PS composite microspheres is based on in-situ suspension polymerization.TiO2 is ipophilic modified.the photocatalytic and antibacterial properties of TiO2/PS composite microspheres were characterized.The main content can be divided into the following two parts.In the first part,the nano titanium dioxide was subjected to a lipophilic treatment to improve the compatibility with the styrene group.Then using BPO as initiator,PVA and TCP as composite dispersant,synthesized TiO2/PS composite microspheres by in-situ suspension polymerization process.The composite microspheres have smooth surface and high balling rate.The process conditions in suspension polymerization has been explored in detail.The experimental result shows that the compatibility of TiO2 with styrene can be improved by the lipophilization treatment.The mass ratio of auxiliaries A to TiO2 should be 0.25:1.At the same time,the use of ultrasonic treatment or high-speed stirring in the dispersion process can enhance the stability of TiO2/styrene suspension systems and reduce the occurrence of TiO2 agglomeration and flocculation.The study of the composite dispersant for suspension polymerization shows that when mTCP:mPVA=2:1,the dispersion effect is best.The reaction temperature should be controlled at 75 ? for 1h,85 ? for 3 h and 95 ? for 1 h.At this condition the composite microspheres had the highest balling rate and the best surface morphology.At the same time,the composite microspheres are characterized by FT-IR,XRD,SEM and EDS analysis.The results showed that nano-titanium dioxide was loaded on the surface of the composite microspheres with a polystyrene matrix.and the anatase nano-titania was still the main component of the composite microspheres.The polymerization process did not change the crystal structure of the nano-titanium dioxide.SEM and EDS results show that the surface of the composite microspheres is uniformly distributed.There is no obvious agglomeration phenomenon on the surface.The second part tests the photocatalytic activity and antibacterial performance of composite microspheres.The photocatalytic results show that the TiO2/PS composite microspheres have good photocatalytic activity.The composite microspheres with a titanium dioxide mass fraction of 3%have the highest photocatalytic activity.When the initial concentration of methylene blue is 20ppm,the degradation efficiency at 3h was 97.3%.The degradation process conforms to the first-order reaction kinetics equation.With the initial concentration of methylene blue solution increasing,the degradation rate increases.The recycling of TiO2/PS composite microspheres was used 8 times,and the degradation efficiency could still maintain 85%.The results of antibacterial experiments showed that 3%wt TiO2/PS composite microspheres had strong antibacterial effect under visible light irradiation.When the contact time was 3 hours,the antibacterial rate of E.coli reached 84.3%.When the contact time is 24 hours,the requirements of the health industry for killing E.coli can be achieved,ie,the antibacterial rate to E.coli is more than 90%.