A new class of polyurethane (PU) biocomposites reinforced with green biocellulose nanofibers (BC) were designed and synthesized. These newly introduced non-cytotoxic and biodegradable composites were synthesized with different ratios of hard to soft segments of the linear, aliphatic hexamethylene diisocyanate (HDI) and polycaprolactone diol (PCL), respectively. The porosity was introduced in the polyurethane matrix using a combination of salt leaching and thermally induced phase separation (TIPS). BC contents were in the range of 0-15 % of the final PU by weight. FTIR spectra showed complete conversion of HDI through the disappearance of the isocyanate and imine characteristic bands (at 2260 cm À1 and 1635 cm À1 , respectively) and appearance of carbonyl group band in PU (at 1730 cm À1 ). The hard to soft segment (i.e., HDI:PCL) ratios in the final PU polymer were quantified from 1 H Nuclear Magnetic Resonance (NMR) spectra by comparing the proton peaks arising for CH 2 CO at 2.25 ppm or OCH 2 at 3.9 ppm to CH 2 N at 2.9 ppm. Results showed that the ratios in the final product were consistent with the amounts added initially during the synthesis. Scanning electron microscope (SEM) images showed that porosity (57-75 %) were formed (pore size in the range of 125-355 mm), with an increase in pore content with the decrease in HDI:PCL content.
New class of green biocomposites were designed and synthesized for tissue engineering applications. These newly introduced non-cytotoxic, biodegradable polyurethane composites had different compositions (i.e., ratio of hard to soft segments) of the linear, aliphatic hexamethylene diisocyanate and polycaprolactone diol. The porosity was introduced in the polyurethane matrix using a combination of salt leaching and thermally induced phase separation (TIPS). The resulting interconnected pore size was characterized using Scanning Electron Microscope (SEM) to be between 125-355 μm. Porosity was determined using liquid displacement and found to be between 70-75% for non-reinforced matrices, 64-70% for reinforcement with 5 wt% biocellulose nanofiber (BCNF), 59-69% for 10 wt% BCNF, and 57-69% for 15 wt% BCNF biocomposite samples. Dependent on the composition, compressive strength showed up to a little less than two-fold increase (85%) for green BCNF reinforcement of 5 wt% and more than two-fold increase (120%) for 10 wt%. The tensile strength also increased up to almost two-fold (114%) for reinforcement with 5 wt% BCNF and to more than two-fold (140%) for 10 wt% reinforcement. Higher degrees of reinforcement showed a detrimental effect on both properties. Properties demonstrate that this novel class of nanostructured biocomposite holds potential to be utilized as scaffolds for tissue regeneration.
New class of green biocomposites were designed and synthesized for tissue engineering applications. These newly introduced non-cytotoxic, biodegradable polyurethane composites had different compositions (i.e., ratio of hard to soft segments) of the linear, aliphatic hexamethylene diisocyanate and polycaprolactone diol. The porosity was introduced in the polyurethane matrix using a combination of salt leaching and thermally induced phase separation (TIPS). The resulting interconnected pore size was characterized using Scanning Electron Microscope (SEM) to be between 125-355 μm. Porosity was determined using liquid displacement and found to be between 70-75% for non-reinforced matrices, 64-70% for reinforcement with 5 wt% biocellulose nanofiber (BCNF), 59-69% for 10 wt% BCNF, and 57-69% for 15 wt% BCNF biocomposite samples. Dependent on the composition, compressive strength showed up to a little less than two-fold increase (85%) for green BCNF reinforcement of 5 wt% and more than two-fold increase (120%) for 10 wt%. The tensile strength also increased up to almost two-fold (114%) for reinforcement with 5 wt% BCNF and to more than two-fold (140%) for 10 wt% reinforcement. Higher degrees of reinforcement showed a detrimental effect on both properties. Properties demonstrate that this novel class of nanostructured biocomposite holds potential to be utilized as scaffolds for tissue regeneration.
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