@article{johnson_faradilla_venditti_lucia_hakovirta_2020, title={Hydrothermal Carbonization of Nanofibrillated Cellulose: A Pioneering Model Study Demonstrating the Effect of Size on Final Material Qualities}, volume={8}, ISSN={2168-0485 2168-0485}, url={http://dx.doi.org/10.1021/acssuschemeng.9b05928}, DOI={10.1021/acssuschemeng.9b05928}, abstractNote={The morphological and physical properties of hydrochar from the hydrothermal carbonization of nanofibrillated cellulose (NFC) are herein described; it was found that the initial starting structure influences the final hydrochar structure to a great extent, as observed by a scanning electron microscope (SEM). Effects of temperature and heating time on the resulted hydrochars were also explored. For comparison purposes, fully bleached macroscopic softwood pulp fibers with a composition similar to the NFC were also converted into hydrochar and characterized. The carbonization of the NFC started at >200 °C although time did not affect the properties of the hydrochar when the hydrothermal carbonization (HTC) was performed at 250 °C. The SEM images of the NFC hydrochar revealed broad nanoscale topological features that may be characterized as nodule-filled surfaces connecting continuously, without a bulk surface as the base, where the nodule dimensions range from 2 to 400 nm. The nanostructure of the NFC did not modify the elemental composition of the resultant hydrochar relative to the hydrochar from softwood. However, the morphology of hydrochar from NFC was different from the hydrochar from the softwood fibers, indicating that there is an advantage to using nanostructured starting material. The NFC hydrochar also had much higher pore volume (0.91 cm3/g) and average pore size (127.1 nm) than the softwood fiber (0.01 cm3/g and 4.5 nm, respectively).}, number={4}, journal={ACS Sustainable Chemistry & Engineering}, publisher={American Chemical Society (ACS)}, author={Johnson, Shelly and Faradilla, RH Fitri and Venditti, Richard A. and Lucia, Lucian and Hakovirta, Marko}, year={2020}, month={Jan}, pages={1823–1830} }
 @article{aggarwal_johnson_saloni_hakovirta_2019, title={Novel 3D printing filament composite using diatomaceous earth and polylactic acid for materials properties and cost improvement}, volume={177}, ISSN={["1879-1069"]}, url={http://dx.doi.org/10.1016/j.compositesb.2019.107310}, DOI={10.1016/j.compositesb.2019.107310}, abstractNote={There are a large variety of different materials currently used for producing 3D printing filaments. In this paper we are investigating the utilization of diatomaceous earth as a potential component for polylactic acid based 3D printing composite materials. The results clearly show that with only minor deterioration of the basic mechanical properties of the 3D printed material at least 10 wt% of the polylactic acid usage can be reduced and replaced by diatomaceous earth. Our thermal analysis also shows nucleation and chain mobility phenomena in the presence of diatomaceous earth particles. The results also show that we are able to engineer 3D printing surfaces with diatomaceous earth protruding from the composite structure and thus allowing us to create high surface area on the 3D printed objects surface. With this research we have shown for the first time an opportunity for cost reduction compared to using pure polylactic acid filaments and a pathway to immobilizing chemical sensing, antibacterial and antiviral agents on 3D printed objects for many applications such as biomedical.}, journal={COMPOSITES PART B-ENGINEERING}, author={Aggarwal, Salonika and Johnson, Shelly and Saloni, Daniel and Hakovirta, Marko}, year={2019}, month={Nov} }
 @article{aggarwal_johnson_hakovirta_sastri_banerjee_2019, title={Removal of Water and Extractives from Softwood with Supercritical Carbon Dioxide}, volume={58}, ISSN={["0888-5885"]}, DOI={10.1021/acs.iecr.8b05939}, abstractNote={Supercritical CO2 (sCO2) removes both water and extractives from wood chips and flakes at 60 °C. The water appears to be mostly displaced by sCO2 because its nominal concentration in sCO2 exceeds its solubility limit. SEM imaging and contact angle measurements show no major differences in surface properties between sCO2-treated and thermally dried flakes, which suggests that their interaction with resin should be similar. An economic analysis for the removal of water and extractives from pine flakes for the manufacture of oriented strand board shows that sCO2 treatment is potentially much more cost-effective than thermal drying from both capital and operational perspectives. The main reasons are that the water is removed by displacement rather than through evaporation, environmental control costs are drastically reduced, and the extractives removed represent a value stream instead of pollutants whose emissions need to be controlled. Because the sCO2 is largely recirculated, the process is greener than conventional direct dryers that generate CO2 from the combustion of wood fines used as a fuel.}, number={8}, journal={INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH}, author={Aggarwal, Salonika and Johnson, Shelly and Hakovirta, Marko and Sastri, Bhima and Banerjee, Sujit}, year={2019}, month={Feb}, pages={3170–3174} }