Biodegradation of poly(ester-urethane)s by a pure strain of micro-organisms

Abstract

SUMMARY: Poly(butylene adipate) (PBA) and poly(ethylene succinate) (PEgS) with a M -n of 2 000 were used as building blocks of poly(ester-urethane)s. Trimethylhexamethylene diisocyanate (TMDI), TMDI/2-methyl-1,5-pentanediamine (MPDA)/TMDI and 4,49-methylenediphenyl diisocyanate (MDI) were used to build diurethane units into the polymer with a final M -n of the order of 30 000. Oxygen consumption was measured during incubation of a pure strain of gram-positive non-sporulating bacteria isolated from an industrial compost for household refuse, in the presence of powder and films. The diurethane junction units and the diurethane model compounds are not assimilated on the time-scale of the present work. The relative biodegradability of PBA, PEgS and the various poly(ester-urethane)s has been assigned to the mobility of the polyester chain segments.

Poly(ester urethane)s with polycaprolactone soft segments: A morphological study

“…[3][4][5][6][7] Polycaprolactone (PCL)-based materials, including polyurethanes, were extensively investigated in the early 1970s by the groups of Cooper, 8 -10 Schollenberger, [11][12][13] and Koleske, 14 -16 who focused on the structure-property relationships. The biodegradability of polyurethanes has been well documented, [17][18][19][20][21][22] and that of PCLs has been reported to depend on the molecular weight, [23][24][25] but a conclusive correlation between the morphology (crystallinity, in this case), molecular weight, and biodegradation properties has not been established yet. This article describes the morphology of poly(ester urethane)s in which the soft segment is PCL and the hard block is built by the reaction of tolylene diisocyanate (TDI) and 1,4-butanediol (BDO).…”

Synthesis and Chemical Recycling of Novel Poly(ester‐urethane)s Using an Enzyme

“…Table 3 shows the yield of the oligomer with an M w of less than 500 by the enzymatic degradation of the adipate-type PEU (x,y,4) in anisole at 110 8C for 6 and 24 h. It was found that the degradation rate of the adipate-type PEU (x,y,4) into the cyclic oligomer increased with the number of methylene groups (y) in the diurethane moiety. That is, PEUs (2,6,4), (3,5,4) and (3,6,4) were almost completely degraded into the corresponding cyclic oligomers for 6 h; on the other hand, the degradation rate of PEUs (2,2,4), (2,3,4) and (3,2,4) were significantly lower. This is ascribed to the flexibility of the diurethane moieties in the polymer chain for incorporation of the ester moiety into the active site of the lipase CA.…”

“…It has been reported that certain kinds of polyurethanes containing a polyester block as a soft segment, poly(ester-urethane)s (PEU), are subject to degradation by microbes. [3][4][5] Takamoto et al reported the lipase-catalyzed degradation of PEU in organic solvent. [6] These results indicated that the introduction of ester linkages into the polymer chain may become an effective way to design a biodegradable and enzymatically recyclable polyurethane.…”

Enzymatic Synthesis and Chemical Recycling of Poly(carbonate‐urethane)

“…Thus, the enzymatically cleavable and biodegradable polyurethane may be produced by combining the low-molecular weight biodegradable hard segment of polyurethane with enzymatically hydrolyzable linkages, such as the ester and carbonate ester. It is reported that certain kinds of polyurethanes containing a polyester block as a soft segment, poly(ester-urethane)s, are subject to degradation by microbes [6][7][8] and by lipase. [9] These results indicate that the introduction of ester linkages into the polymer chain may become an effective way to design a biodegradable and enzymatically recyclable polyurethane.…”