Polyurethane frontal

S. Chen, J. Sui, L. Chen, and J. A. PotMAN, Polyurethane-nanosilica hybrid nanocomposites synthesized by frontal polymerization, J. Polym. Sci. Part A - Polym. Chem., 43 (2005), pp. 1670-1680. 

In 2000, we have begun our research on this topic paying particular attention to the possibility of finding new chemical systems able to frontally polymerize and new FP applications. Specifically, we have studied polyurethanes (19, 20), polyester tyrene resins (21), polydicylopentadiene (22) and its BPNs with polyacrylates (23), Furthermore, we were able to prepare films (24) and to apply FP to the consolidation of porous materials (i.e. stones, woods, flaxes, papers), in particular -but not only- those having a historical-artistic interest (24), In this chapter we present a brief overview of these recent findings. 

Experience over a three year period with polytetrafluoroethylene (Proplast) is reported together with early results on chlorinated polyethylene which is claimed to have advantages over other available materials. The sunlight stability of facial prostheses presents an obvious problem and the behaviour of polyurethanes in this respect has been examined. Experimental reconstructive prostheses have involved for example silicone rubber in the repair of nasal septal perforation and ear reconstruction and polytetrafluoroethylene in frontal sinus reconstruction. Breast reconstruction and augmentation with silicone rubber and polyurethanes, tissue reaction to polyurethane coated implants, and the use of polyethylene in this type of surgery have been discussed. A useful review on silicone fluids (which are for example iiyected to improve scars ) has appeared. 

Frontal polyurethane polymerization [13-15], frontal atom transfer radical polymerization [16], and frontal ring-opening metathesis polymerization (ROMP) [17] all suffer from short pot lives that is, bulk polymerization occurs in less than an hour. In some cases, the only way to avoid even faster bulk polymerization is to cool the reagents. For example, with frontal ring-opening metathesis polymerization of dicyclopentadiene with a Grubbs catalyst, the starting materials had to be frozen to prevent rapid bulk polymerization [17]. 

Most work has been with free-radical systems but other chemistries can be used. Begishev etal. studied frontal anionic polymerization of e-caprolactam [18, 19], and epoxy chemistry has been used as well [20-23]. Mariani ctal. demonstrated frontal ring-opening metathesis polymerization [17]. Fiori et al. produced polyacrylate-poly(dicydopentadiene) networks frontally [24], and Pojman etal. studied epoxy-acrylate binary systems [25]. Polyurethanes have been prepared frontally [13,14, 26]. Frontal atom transfer radical polymerization has been achieved [16] as well as FP with thiol-ene systems [27]. Recent work has been done using FP to prepare microporous polymers [28-30], polyurethane-nanosilica hybrid nanocomposites [31], and segmented polyurethanes [32]. 

Chen, S.H., Sui, )., and Chen, L. (2005) Segmented polyurethane synthesized by frontal polymerization. Colloid. 

Texter and Ziemer created polyurethanes via FP in microemulsions. Chen et created epoxy-polyurethane hybrid networks frontally. Pot lives were on the order of hours. Hu et frontally prepared urethane-acrylate copolymers in... 

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