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[摘要]：The goal of this work was to prepare polyurethanes having P[AB] co-polyoxetane soft blocks, where A is a surface active (fluorous) or PEG-like side chain and B represents a desired function (alkylammonium). To this end, poly(2,2-substituted-1,3-propylene oxide) ran-co-telechelics with bromobutoxymethyl (-CH2O(CH2)(4)-Br) and either trifluoroethoxymethyl (3FOx, -CH2OCH2CF3)) or PEG-like (2-(2-methoxyethoxy)ethoxy)methyl (ME2Ox, (-CH2(OCH2CH2)(2)OCH3)) side chains were prepared via cationic ring-opening polymerization. Characterization utilized H-1 NMR spectroscopy, temperature modulated differential scanning calorimetry (MDSC) and thermogravimetric analysis (TGA). Molecular weights (M-n) by H-1 NMR end group analysis were similar to 6 kDa while broimobutoxymethyl co-telechelic T(g)s were -68 and -48 degrees C for ME2Ox and 3FOx, respectively. Bromobutoxymethyl groups were completely substituted with NN-dimethylalkyl amines to obtain oxetane B repeats with six carbon (C6) and twelve carbon (C12) alkylammonium side chains. P[AB] T(g)s remained low after amine substitution. Co-telechelics were incorporated into polyurethanes (PUs) having 4,4'-(methylene his)-cyclohexyl isocyanate) (H12MDI) and butanediol (BD) as the hard block (30 wt %). Characterization by 1H NMR, GPC, MDSC, and TGA is described. From DSC data, using the Fox equation, the weight fraction of pure soft block in the soft block domain (w(1)) was very high (0.96-0.99) for polyurethanes with fluorous soft blocks, while soft blocks with PEG-like side chains were phase mixed (w(1) = 0.73-0.75). To our knowledge, this is the first time that a polycationic telechelic has been incorporated in a polyurethane. TGA in nitrogen confirmed stoichiometry and showed that both alkylammonium co-telechelics and polyurethanes had good thermal stability. |
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