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Water-blown rigid polyurethane foams from soy-based polyol were prepared and their structure-property correlations investigated. Cellulose microfibers and nanoclays were added to the formulations to investigate their effect on morphology, mechanical, and thermal properties of polyurethane foams. Physical properties of foams, including density and compressive strength, were determined. The cellular morphologies of foams were analyzed by SEM and X-ray micro-CT and revealed that incorporation of microfibers and nanoclays into foam altered the cellular structure of the foams. Average cell size decreased, cell size distribution narrowed and number fractions of small cells increased with the incorporation of microfibers and nanoclays into the foam, thereby altering the foam mechanical properties. The morphology and properties of nanoclay reinforced polyurethane foams were also found to be dependent on the functional groups of the organic modifiers. Results showed that the compressive strengths of rigid foams were increased by addition of cellulose microfibers or nanoclays into the foams. Thermogravimetric analysis (TGA) was used to characterize the thermal decomposition properties of the foams. The thermal decomposition behavior of all soy-based polyurethane foams was a three-step process and while the addition of cellulose microfibers delayed the onset of degradation, incorporation of nanoclays seemed to have no significant influence on the thermal degradation properties of the foams as compared to the foams without reinforcements.

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This study reports development of digital light processing (DLP) mediated 3D printed customized bone scaffolds. Bioactive fluorcanasite glass ceramic was incorporated within photocurable resin matrix and the suspensions were 3D printed towards developing composite bone scaffolds. Physico-chemical interaction in the biocomposite bone scaffolds were investigated using infrared spectroscopy, x-ray diffraction, and field emission scanning electron microscopy. Further, the mechanical properties of the composite scaffold samples were also evaluated to understand the strengths of the samples in terms of its fracture toughness, flexural strength, and compressive strength. Infrared spectroscopy results demonstrated an active interaction between the acrylate functionalities of the polymer with the bioactive fluorcanasite glass ceramic reinforcement. This was further substantiated with x-ray diffraction results, demonstrating rise in the bioactive crystalline peaks with corresponding increase in the fluorcanasite glass ceramic loading. Later, the samples were also evaluated for in-vitro cellular response in terms of cell viability, proliferation, adhesion, and interaction. The surface hydrophilicity responsible for osteogenic interaction was also studied with contact angle goniometry. With increase in fluorcanasite loading in the formulation, the hydrophilicity was found to increase over the sample surface which in turn was found to enhance cell adhesion and proliferation, as revealed byin-vitro MTT assay and also fluorescence microscopy. To establish the efficacy of DLP technique, two different porous architectural designs were 3D printed and investigated with synchrotron micro-computed tomography. The microtomographs revealed precise microarchitecture and interconnected porosity within the scaffolds.

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