Synthesis segmented polyurethanes

Ishihara K, Hanyuda H, and Nakabayashi N. Synthesis of phospholipids polymers having a urethane bond in the side chain as coating material on segmented polyurethane and their platelet adhesion resistant properties. Biomaterials, 1995, 16(11), 873-879. 

Segmented polyurethanes were synthesized from the a, to diol polyethers listed in Table I and the diisocyanates IV, V, and VI by the two-step process shown in Figure 1 or the three-step process in Figure 2. In all cases, chain extension of isocyanate-terminated prepolymers was accomplished with ethylenediamine. The synthesis took place in a 2 1 (v/v) mixture of dimethyl sulfoxide and 4-methyl-2-pentanone at 60°C. 

To obtain a solution suitable for casting on test surfaces, the segmented polyurethanes after synthesis were precipitated by methanol (which also terminated excess isocyanate groups) and after drying were redissolved in dimethylformamide (DMF). 

Figure 1. Two-step synthesis leading to Type I segmented polyurethanes.

Figure 2. Three-step synthesis leading to Type II and Type III segmented polyurethanes (cf. Table 111).

Vaidya, A., Oiaudhury, M.K. Synthesis and surface properties of environmentally responsive segmented polyurethanes. J. Colloid Interface Sci. 249, 235—245 (2002)... 

Synthesis and charaderization of novel segmented polyurethane/day nanocomposite via poly(s-caprolactone)/ clay. /. Pdym. Sd. A Polym. Chem.,... 

Vaidya, A. Chaudhury, M. K., Synthesis and Surface Properties of Environmentally Responsive Segmented Polyurethanes. J. Coll. Interface Sci. 2002,... 

The three step synthesis brings a new variable in the phase separation of segmented polyurethanes. In a polyurethane synthesised by a two step process, we may have a phase separation as shown in Fig. 3. In the three step process, the diisocyanate "connector" either remains in the "soft" phase, in which case the polyether acts as a chain of double molecular weight, with a stuctural "defect" in the midle, or the "connector" may associate with the "hard" phase (Fig. 4), the results of which would be that the polyether chain would be fixed at each end of its primary length to a "hard" segment junction. 

Rueda-Larraz L, et al. Synthesis and microstructure-mechanical property relationships of segmented polyurethanes based on a PCL-PTHF-PCL block copolymer as soft segment. Eur Polym J 2009 45(7) 2096-109. 

Korematsu A, Takemoto Y, Nakaya T, Inoue H. Synthesis, characterization and platelet adhesion of segmented polyurethanes grafted phospholipid analogous vinyl monomer on surface. Biomaterials 2002 23 263-71. 

Lan PN, Comeillie S, Schacht E, Davies M, Shard A. Synthesis and characterization of segmented polyurethanes based on amphiphilic polyether diols. Biomaterials 1996 17(23) 2273-80. 

Tan H, Li J, Luo J, Xie X, Zhong Y, Fu Q. Synthesis and properties of novel segmented polyurethanes containing alkyl phosphatidylcholine side groups. Eur Polym J... 

Chen TK, Tien YI, Wei KH. Synthesis and characterization of novel segmented polyurethane/clay nanocomposite via poly(E-caprolactone)/clay. J Polym Sci Part A Polym Chem July 1999 37 2225-33. 

Francolini I, Crisante F, Martinelli A, D llario L, Piozzi A. Synthesis of biomimetic segmented polyurethanes as antifouling biomaterials. Acta Biomater 2012 8 549-58. http //dx.doi.0rg/lO.lOl6/j.actbio.2Oll.lO.O24. 

Guelcher SA, Gallagher KM, Didier JE, Kbnedinst DB, Doctor IS, Goldstein AS, et al. Synthesis of biocompatible segmented polyurethanes from aliphatic diisocyanates and diurea diol chain extenders. Acta Biomater 2005 4 471-84. 

Zhang X, Tan D, Li J, Tan H, Fu Q. Synthesis and hemocompatibity evaluation of segmented polyurethane end-capped with both a fluorine tail and phosphatidylcholine polar head groups. Biofouhng 2011 27(8) 919—30. 

---