FUNDAMENTAL STUDIES ON RADICAL POLYMERIZATION OF RODLIKE MACROMONOMERS

以4-乙烯基苯氧基和2-甲基丙烯酸基乙氧基二氯环戊二烯基钛（IV）为引发剂，在室温下用正己基异氰酸酯（HIC）进行活性配位聚合，成功制备了分子量分布相对较窄（Mw/Mn < 1.2）的聚正己基异氰酸酯端棒状单体（VB-HIC-n和MA-HIC-n）。研究了棒状大单体与相应的低分子量单体如苯乙烯或MMA的自由基共聚行为，并总结了HIC聚合度的函数。在VB-HIC-n与苯乙烯的共聚过程中，棒状大单体（1/r_1）的表观共聚能力几乎与苯乙烯相当，表明反应活性主要由末端双键的化学反应活性决定。另一方面，在MA-HIC-n与MMA的共聚过程中，单体总浓度和聚合度的1/r_1值几乎不变，但低于MMA，这很可能是由于MA-HIC-n与PMMA的传播链不相容所致。自由基均聚的大单体提供了新的明确的梳状，圆柱形刷组成的棒作为一个分支链。用光散射、SAXS和粘度法研究了刷的尺寸特性。用虫链模型分析了刷体在稀溶液中旋转半径与分子量的关系，并将其合理化为棒侧链长度的函数。发现电刷的库恩统计长度随杆长线性增加。

Styryl- and methacrylate-ended rodlike macromonomers consisting of poly(n-hexyl isocyanate) (VB-HIC-n and MA-HIC-n) with relatively narrow molecular weight distribution (Mw/Mn < 1.2) have successfully been prepared in CH_2Cl_2 at room temperature by living coordination polymerization of n-hexyl isocyanate (HIC) using 4-vinylbenzyloxy- and 2-methacrylate ethyloxy-dichloro(cyclopentadienyl)titanium(IV) as initiator, respectively. The radical copolymerization behavior of the rodlike macromonomers with corresponding low molecular weight monomers such as styrene or MMA has been studied and summarized as a function of degree of polymerization of HIC. In the copolymerization of VB-HIC-n with styrene, the apparent copolymerizabilities of the rodlike macromonomer (1/r_1) seem to be almost equivalent to the styrene, suggesting that the reactivity is mainly determined by the chemical reactivity of the ended double bond. On the other hand, in the copolymerization of MA-HIC-n macromonomers with MMA the value of 1/r_1 is almost constant for total monomer concentration and degree of polymerization but lower than that of MMA, most likely due to the incompativility between MA-HIC-n and PMMA propagating chain.Radical homopolymerization of the macromonomers affords novel well-defined comblike, cylindrical brushes consisting of the rods as a branched chain. The dimensional properties of the brushes have been studied by means of light scattering, SAXS, and viscometry. The molecular weight dependence of radius of gyration of the brushes in dilute solution is analyzed in terms of wormlike chain model and rationalized as a function of the side chain length of the rods. The Kuhn statistical length of the brushes is found to linearly increase with the rod length.