Effect of different nanoparticles on the properties and enzymatic hydrolysis mechanism of aliphatic polyesters

Novel poly(butylene succinate) nanocomposites containing strontium hydroxyapatite nanorods with enhanced osteoconductivity for tissue engineering applications

“…However, Vasileiou et al reported that the presence of fumed silica particles has a negative effect on the degradation level of PESu since it reduces macromolecular chain mobility. A reduced hydrolysis rate was also found in PPSeb/MMT nanocomposite, which is in agreement with some reported findings in literature [17,27,28]. Enzymatic degradation of polyesters can be affected by several factors, having to do with the chemical structure, the type and amount of filler, the solidstate of the degraded specimen.…”

“…The nanocomposite PBSu/ SrHAp nrds 2.5 wt% could not be measured under these conditions of deformation, due to its significant brittleness. As can be seen E* gradually decreases with increasing temperature and a transition is observed between -60 and -10°C, which is ascribed to the glass transition temperature of PBSu (Tg) [17]. At low temperatures the storage modulus is higher compared with neat P,Su confirming the reinforcement effect of the nanorods.…”

“…However, same small differences are recorded in the oxygen region and mainly of the O 1 ester and O 3 carboxylic group (Figure 3). These values are slightly to lower binding energies indicating the existence of some interactions between PBSu and these nanoparticles [17]. After the peak analysis in the Sr3d region of the XPS spectrum at (130.5-137.6 eV) for the PBSu/SrHAp nrds 2.5 wt% nanocomposite, it is clear that new peaks are formed, indicating the formation of new covalent bonds between SrHAp nrds nanoparticles and PBSu (Figure 4).…”

“…This fact can be attributed to the restriction of the molecular motion of the PBSu macromolecules due to the fine dispersion of the nanofillers, which leads to increased interactions with the polymer matrix [15,22]. The extent of this reinforcement is limited above the T g due to the higher molecular motion of the PBSu macromolecular chains [17]. Thus above the T g the storage modulus sharply decreases and all nanocomposites have almost similar storage moduli.…”

“…Enzymatic degradation of polyesters can be affected by several factors, having to do with the chemical structure, the type and amount of filler, the solidstate of the degraded specimen. Hydrophilic/hydrophobic balance segments within the main chain, molecular weight, frequency of ester bonds along the macromolecular chains, as well as segmental mobility of the macromolecules can also influence the rate of biodegradation [17]. The molecular weight could be a notable factor for such differences since nanocomposites with 1.0 and 2.5 wt% of nanofiller have higher molecular weights than neat PBSu and this could justify the faster enzymatic hydrolysis rates observed.…”