Polyurethanes biodegradation characteristics

Effect of processing parameters on polyurethane biodegradation characteristics... 

In dentistry, silicones are primarily used as dental-impression materials where chemical- and bioinertness are critical, and, thus, thoroughly evaluated.546 The development of a method for the detection of antibodies to silicones has been reviewed,547 as the search for novel silicone biomaterials continues. Thus, aromatic polyamide-silicone resins have been reviewed as a new class of biomaterials.548 In a short review, the comparison of silicones with their major competitor in biomaterials, polyurethanes, has been conducted.549 But silicones are also used in the modification of polyurethanes and other polymers via co-polymerization, formation of IPNs, blending, or functionalization by grafting, affecting both bulk and surface characteristics of the materials, as discussed in the recent reviews.550-552 A number of papers deal specifically with surface modification of silicones for medical applications, as described in a recent reference.555 The role of silicones in biodegradable polyurethane co-polymers,554 and in other hydrolytically degradable co-polymers,555 was recently studied. 

Vegetable oil-based hyperbranched polymers have considerable potential in biomedical applications. This is due to their unique structural characteristics along with their biodegradability and biocompatibiUty. Preliminary studies show that vegetable oil-based hyperbranched polyurethanes have the potential to be used as biomaterials in biomedical applications such as drug delivery systems, biomedical smart materials and catheters. ... 

It is believed that most of PUR biodegradation occurs by the action of esterases, however polyester-polyurethane degrading enzymes have been purified and their characteristics have been reported. These enzymes have a hydrophobic binding domain at the surface of the PUR, and a catalytic domain [22]. But there is no evidence that the urethane linkage has been broken. 

Hashizume R, Fujimoto KL, Hong Y, Amoroso NJ, Tobita K, Miki T, et al. Morphological and mechanical characteristics of the reconstructed rat abdominal wall following use of a wet electrospun biodegradable polyurethane elastomer scaffold. Biomaterials April 2010 31(12) 3253-65. 

Table 15.3 Some Selected biodegradable polyurethane scaffolds and their mechanical characteristics...

Polyurethanes can be considered to have both the structural characteristics of polyesters and polyamides, whereas polyureas are similar to that of poly(diamide)s. Their susceptibility to biodegradation can be expected to be similar to that of polyesters and polyamides. Polyurethanes derived from aliphatic diisocyanates are degraded faster than those derived from aromatic... 

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