Accelerated hydrolytic degradation of Poly(l-lactide)/Poly(d-lactide) stereocomplex up to late stage

Crystallization and hydrolytic/thermal degradation of a novel stereocomplexationable blend of poly(L-2-hydroxybutyrate) and poly(D-2-hydroxybutyrate)

“…The M n values were higher for the P(L-2HB)/P(D-2HB) blend than for pure P(L-2HB) and P(D-2HB), when compared for the same degradation periods. The remaining weight percentages and M n values reflect that the P(L-2HB)/P(D-2HB) blend has a superior hydrolytic degradation resistance as compared with pure P(L-2HB) and P(D-2HB); this is in agreement with the experimental results of hydrolytic degradation [16][17][18][19] and theoretical calculations 34 for a PLLA/PDLA stereocomplex relative to pure PLLA and PDLA. The value of M w /M n of pure P(L-2HB), P(D-2HB) and their blend increased in the first 8 days, followed by a decrease or plateau.…”

“…This is consistent with the observations in the case of the hydrolytic degradation of PLA-based materials in neutral media. 16,19,[31][32][33] The M n and M w /M n of pure P(L-2HB), P(D-2HB) and their blend, after hydrolytic degradation for different periods, were estimated from the GPC profiles and are plotted in Figure 6 as a function of degradation time. The M n values of pure P(L-2HB), P(D-2HB) and their blend decreased rapidly in the first 4, 4 and 8 days, respectively, followed by a less rapid decrease after these periods.…”

“…The spherulite growth or crystallization of the P(L-2HB)/ P(D-2HB) stereocomplex is completed in a substantially shorter period of time as compared with those of pure P(L-2HB) and P(D-2HB). From the results reported for PLLA/PDLA blends, [16][17][18][19][20] it is expected that the resistance of P(L-2HB)/P(D-2HB) blends to hydrolytic and thermal degradation should be higher than those of pure P(L-2HB) and P(D-2HB). Moreover, optically pure P(2HB) can form a heterostereocomplex with non-substituted PLA having a configuration opposite to that of P(2HB), 22 whereas optically pure phenyl-substituted PLA is reported to have a higher intermolecular interaction with non-substituted PLA having a configuration opposite to that of phenyl-substituted PLA.…”

“…The spherulite growth or crystallization of the P(L-2HB)/ P(D-2HB) stereocomplex is completed in a substantially shorter period of time as compared with those of pure P(L-2HB) and P(D-2HB). From the results reported for PLLA/PDLA blends, [16][17][18][19][20] it is expected that the resistance of P(L-2HB)/P(D-2HB) blends to hydrolytic and …”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] Stereocomplexation between PLLA and its enantiomer poly(D-lactide) (that is, poly(D-lactic acid) or PDLA) can yield biodegradable materials having superior mechanical performance and resistance to hydrolytic and thermal degradation relative to pure PLLA and PDLA. [16][17][18][19][20] Poly(2-hydroxybutyrate) (that is, poly(2-hydroxybutanoic acid) or P(2HB)) is a biodegradable polymer with the structure of a poly(lactide) (that is, poly(lactic acid) or PLA) in which methyl groups are substituted with ethyl groups. A stereocomplex can also be formed by blending substituted enantiomeric PLAs, that is, poly(L-2-hydroxybutyrate) [P(L-2HB)] and poly(D-2-hydroxybutyrate) (P (D-2HB)).…”