Preparation And Properties Of Functionalized POSS Modified Polymethacrylic Resin

In recent years,the development of organic and inorganic materials has been challenged.In order to improve the defects of the original material,such as light weight,good transmittance,strong rigidity,low density,and preserve their own performances,thus organic-inorganic nano-modified materials have been emerged.Polyhedral oligomeric silsesquioxane?POSS?was a type of nano-particles composed of a core of silicon-oxygen interphase and a shell of an organic functional group,which has low surface energy and good heat resistance.POSS can be used as the base material of a new type of polymer materials.According to the activity of the organic functional group connecting on Si atom,POSS can be introduced into the polymer materials by various methods,such as polymerization,grafting,surface bonding and physical blending,to significantly improved polymers in terms of mechanical properties,thermal properties,optical properties,and magnetic properties.Thereby the real organic-inorganic nano-modified materials could be synthesized at the molecular level.To correspond with these,the concrete research contents and consequences of this paper were as follows:?1?Hexyl methacryloxypropyl POSS(T₈^MA/7O-POSS)and heptaisobutyl methacryloxypropyl POSS(T₈^MA/7i-POSS)were synthesized via co-hydrolysis.The quaternary ammonium POSS?POSS^-·8N⁺?CH₃?₄?was synthesized by a complete hydrolysis.The structures of the POSSs above were characterized by FT-IR,¹H-NMR,²⁹Si-NMR and MS.Results verified that they achieved expected molecular structures.T₈^MA/7i-POSS and POSS^-·8N⁺?CH₃?₄ had regular crystal structure could be seen from the XRD spectra.And from the TEM and SEM images,it can be intuitively seen that the T₈^MA/7O-POSS molecules were spherical,and the T₈^MA/7i-POSS molecules were tetragonal,and the POSS^-·8N⁺?CH₃?₄ molecules were oblate.The results of TGA test manifested that T₈^MA/7O-POSS and T₈^MA/7i-POSS both had outstanding thermal properties,and POSS^-·8N⁺?CH₃?₄ had moderate thermal stability.?2?A series of PMMA-co-T₈^MA/7O-POSS polymer materials were prepared by secondary copolymerization method,and AIBN as an initiator.Firstly,the methyl methacrylate?MMA?was used to synthesize the intermediate,and then the heptayl methacryloxypropyl POSS(T₈^MA/7O-POSS)were added to prepare polymer materials.FT-IR,¹H-NMR,XRD and XPS characterization methods indicated that POSS has formed hybrid polymers structure with PMMA,and the polymers were amorphous structure which contained C,O,and Si three elements.The cross-sectional SEM image manifested that the impact fracture surface of the polymers were scaly section,which surface was rough and inside contained granular micro-structures.Based on AFM images,the average roughness?Ra?and root-mean-square roughness?RMS?of the polymers film were affected by the addition of POSS.According to the results of TGA and DSC,the thermal stability and glass transition temperature?Tg?of the polymers were improved by POSS modification.The optical performance of the polymers had decreased with the increase of POSS content.The polymer materials had splendid mechanical properties when the T₈^MA/7O-POSS content was 15%.Compared with the primary copolymer and the secondary copolymer with the 15%of T₈^MA/7O-POSS content,although the thermal stability and Tg of the primary copolymer was higher,and the mechanical properties and optical properties were slightly reduced.?3?A series of PMMA-co-T₈^MA/7i-POSS polymer materials were prepared by secondary co-polymerization.Methyl methacrylate?MMA?and heptaisobutyl methacryloxypropyl POSS(T₈^MA/7i-POSS)were used to synthesize prepolymer,and BPO as an initiator.FT-IR,¹H-NMR,XRD and XPS characterized that POSS was grafted into the PMMA molecular segment and wrapped in the interior of PMMA,and the polymers were amorphous structure without crystallization,and contained three elements of C,O,Si.It can be obtained from the SEM and AFM images that the impact section of the polymers were distinct layered fracture surface containing particulate structure,and the surface roughness increases were affected by the addition of POSS.TGA,DSC and mechanical properties test results revealed that the thermal stability and Tg of the polymers were improved.When the content of T₈^MA/7i-POSS was 15%,the mechanical properties of the polymer materials were optimal.However,the transmittance results evidenced that the optical performance were slightly decreased with the addition of POSS.When 9%of T₈^MA/7i-POSS content was added in the primary copolymerization,the thermal stability and Tg of obviously increased,and the optical properties and mechanical properties sliding down compared the secondary copolymer with the same content.