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超小粒子在高分子基体中的组装与改性研究
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摘要
尺寸小于基体链均方回转半径的超小粒子添加到高分子基体中可以导致反常的现象,例如黏度降低。该现象不符合传统理论:爱因斯坦黏度增加理论~([1])。在本工作中,我们以直径为1 nm的Keggin型多金属氧簇[CoW_(12)O_(40)]~(6-)为无机核,通过静电作用将含有RAFT引发基团的有机配体修饰在簇的表面,然后以graft from的方式在簇外围接枝聚苯乙烯链,获得了聚合度分别为5,10,20和30的星状聚合物(Fig.1a)~([2])。研究发现,将这些星状聚合物作为超小粒子添加到高分子基体中,随着分子量的增加,星状聚合物在基体中的组装形貌由聚集逐渐转变为均匀分散的状态(Fig.1b),并且表现为玻璃化转变温度和黏度的降低。
The incorporation of ultrasmall nanoparticles into polymer matrix, where the size of ultrasmall nanoparticles is smaller than the radius of gyration of matrix chains, can lead to anomalous phenomenon such as the decrease of viscosity. This phenomenon does not obey the classic Einstein's theory which predicts an increased viscosity. In this work, we used the Keggin-type cluster [CoW_(12)O_(40)]~(6-) as inorganic core whose diameter is 1 nm and modified it with RAFT agents by electrostatic interaction. By further grafting polystyrene chains onto the [CoW_(12)O_(40)]~(6-), we prepared a series of star-like clusto-supramolecular polymers(CSP) whose degrees of polymerization are 5, 10, 20 and 30, respectively. Upon the incorporation of these CSP into polystyrene matrix as ultrasmall nanoparticles, their assembling morphology changed from aggregated state to dispersed state with the increase of molecular weights, meanwhile accompanying with the decrease of viscosity and glass transition temperature.
引文
[1]Mackay,M.E.;Dao,T.T.;Tuteja,A.;Ho.D.L.Nat.Mater.2003,2:762.
    [2]Li,D.;Li,H.;Wu,L.Polym.Chem.2014,5:1930.

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