Synthesis And Application Of Styrene/Siloxane Block Copolymer

Polystyrene(PS)has the advantages of good transparency and low cost,but due to its own shortcomings such as temperature resistance and poor surface properties,it limits the application of the material itself.in order to solve the above problems,copolymerization modification methods are usually used to introduce polysiloxane into the polystyrene structure to improve the thermal properties and surface properties of the PS material itself.Chlorosilane-terminated polystyrene and siloxaneizationIn this paper,the active terminal polystyrene lithium with controllable molecular weight and narrow molecular weight distribution was synthesized by anionic polymerization.Chlorosilane was used to capping the end of the polystyrene.The synthetic functionalized PS was reacted with trimethylsilanol to study the reaction efficiency of small molecule silanol and functionalized PS.the increase of reaction time is beneficial to the reaction,the capping rate reached 13.20%at 25? for 6 hours;the reaction temperature increased,Does not beneficial the reaction capping reaction to proceed,the capping rate is 14.91%when the reaction temperature is 60?.Synthesis of Dimethyl Polysiloxane-Poly Styrene block copolymerThe functionalized PS and HTPDMS are used as monomers to react in the solvent cyclohexane to prepare the PS-b-PDMS-b-PS block copolymer.The chemical structure of block copolymers was characterizated by GPC,FT-IR,1HNMR.To explore the efficiency of the chain expansion reaction,the increase of the reaction temperature,the decrease of the block rate in the product,When the reaction temperature is 25?,it can reach 16.16%;when the reaction time is increased,the conversion rate of the product increases,and the reaction time is 36 h,it increases to 5.34%,the increase range is small;when the reaction concentration of functionalized polystyrene is increased and the feed ratio is changed,the block ratio of the product increases greatly,which is conducive to the chain extension reaction,and the conversion rate can reach 24.25%.The materials with different content of PS-b-PDMS-b-PS were tested by DSC and TGA.The results of DSC and TGA showed that the glass transition temperature and thermal decomposition temperature of PS decreased with the increase of Siloxane content.The static water contact angle test showed that the water contact and surface energy of PS-b-PDMS-b-PS increased with the increase of polysiloxane content.Synthesis of polymethyltrifluoropropylsiloxane-Polystyrene block copolymerThe PS-b-PMTFPS-b-PS block copolymers were prepared by reaction in a molten system using functionalized PS?HTPMTFPS as monomer.The chemical structure of block copolymer was characterized by GPC?FT-IR?1HNMR spectra.The increase of reaction temperature is conducive to the synthesis of the product,and the conversion rate can reach 46.94%at 200 ? for 4 h;with the increase of reaction time,the conversion rate increases to 56.04%;under different reaction systems,the conversion rate in solvent system is the highest,which is only 12.53%,while in melt system,the conversion rate is more than 40%.The thermal performance test and surface performance test of the prepared materials with different contents of block copolymer have been carried out.DSC and TGA results show that as the content of polyfluorosiloxane in the product increases,the PS glass transition temperature and the The thermal decomposition temperature shows a decreasing trend;the water contact angle test shows that as the content of polyfluorosiloxane gradually increases,the water contact of the material gradually increases,When the content of polyfluorosiloxane is 12.93%,the contact angle reaches 121.5° and the surface energy is 4.29 mJ·cm-2.