Synthesis and Characterization of Wormlike Three-Arm Poly(n-hexyl isocyanate) Star Polymers

摘要: We have previously reported the use of titanium alkoxide complexes as initiators for living polymerization isocyanates. In this paper, we present synthesis a trimetallic initiator, 2, comprised three alkoxides connected to central organic core and catalyst form three-arm star polymers which contain rigid polyisocyanate arms. Kinetic molecular weight experiments confirm that complex like its monometallic analogue, 6, initiates n-hexyl isocyanate stars obtained from 2 are completely symmetrical. The number-average polymer increases linearly with monomer-to-catalyst ratio used, indicates lack chain transfer during polymerization. A comparison rates by 6 at fixed initial monomer concentrations (k = (3.99 ± 0.2) x 10 -3 M min -1 , k (3.84 0.1) ) demonstrates all centers in active propagate independently one another. solution properties these new were examined through tandem GPC/light scattering viscometry experiments. Light shows there is 55% reduction mean-square radius gyration (g / linear 0.45 0.05) same weight. experimental value g approaches rod limit arms can be construed stiff, wormlike chains. Additionally, 28% intrinsic viscosity equivalent. Finally, 30% w/w displays nematic, lyotropic liquid crystalline mesophase.