Functionalization Of SEBS And The Application In Preparing Inorganic Nano-Materials

The grafting reaction, leading to chemical modification of SEBS to impart polarity using maleic anhydride was done by using the solution method in this paper. We prepared a series of SEBS-g-MAH products by controlling the amount of DCP and MAH in the reaction, and the grafting degrees of the products were 0.75%, 1.09%, 1.35%, 1.80%, 2.30% respectively. FTIR spectra of SEBS before and after functionalization with MAH were performed, indicating that MAH molecules were grafted on SEBS chains. The grafting degree of the SEBS-g-MAH sample was determined by acid-base titration method.Acid-base titration method is a classical method for determine the grafting degree of SEBS-g-MAH. However, there still exist some problems. Finally, the paper analyzed the experiment details, including sample concentration, standard titration solution concentration and temperature of titration, to get an optimum test method.The employment of SEBS-g-MAH and sol-gel precursor of titania resulted in the uniform dispersion of titania in the SEBS matrix. SEBS-g-MAH/TiO₂ transparent composite films containing different amount of titanium are prepared by changing the amount of sol-gel precursor of titania. Interactions between titania oligomers and PEB-g-MAH blocks are believed to play an important role in the formation of the transparent nanoscomposite films, which titania oligomers can be segregated into the PEB-g-MAH domains. Due to the unfavorable interactions between titania oligomers and PS or PEB blocks, neat SEBS/titania composite film is yellow and opaque, indicating that phase separation occurs between titania and SEBS or the formation of large titania particles.The solubility of SEBS-g-MAH/TiO₂ transparent composite films in toluene decreased significantly. TEM images illustrates that titania have good dispersibility and stability in SEBS-g-MAH matrix. The XRD result doesn't exhibit any noticeable peaks, indicating that titania in the film is amorphous.The stress-strain curves illustrates that the initial modulus and the tensile strength at break increase when titania is added into SEBS-g-MAH. It should be noted that the nanocomposite films show excellent stretchability as evidenced by the very high elongation at break, which only slightly decreases in contrast to SEBS-g-MAH.DSC scans of SEBS and SEBS/titania nanocomposite illustrate that Tg of Rubbery block (PEB) in SEBS, SEBS-g-MAH and SEBS-g-MAH/titania nanocomposites increases in turn.The results indicate that the interaction of SEBS-g-MAH chains, and that between SEBS-g-MAH chains and titania nanoparticles are larger than that of neat SEBS chains, which leads to restriction in chain movement and thereby the higher glass transition.The thermal degradations of composites were measured using a thermogravimetric analysis. One can see that the initial degradation temperature of SEBS-g-MAH/titania3 increased compared to SEBS-g-MAH. The temperature of 50% weight loss for SEBS-g-MAH, SEBS-g-MAH/titania3 composite and SEBS-g-MAH/titania5 composite increases in turn. The increase of the thermal stabilities of the SEBS-g-MAH/titania composites is attributed to the more interaction between SEBS-g-MAH chains and titania nanoparticles.Titanium dioxide nanoparticles were prepared through high temperature process of SEBS-g-MAH/TiO₂ composite films. The resules of SEM indicate the Titanium dioxide nanoparticles have spherical shape and its diameter is smaller than 200nm. The tests of surface area and pore size tell us the nanoparticles have bigger surface area and mesoporous characteristics. And then its catalytic properties were reseached. The results indicate titanium dioxide nanoparticles have obvious catalytic properties for the degradation of methylene blue.