Comparison of thermal interfacial performance of carbon nanofiller-based polymer composites

Extended Abstract deposited in White Rose Online Repositor

A low-cost way to reduce greenhouse effects

Oak wood precursor was used for preparing low-cost CO2 sorbents. Adsorption is proposed as a cheaper alternative to chemical absorption, which is uneconomical, thus reducing the cost associated with the capture step. The raw material has been carbonised either by pyrolysis or by a hydrothermal carbonisation (HTC). Resulting biochars were then activated using CO2 . Initial chars and their activated counterparts were characterised by SEM imaging and N2 sorption measurements at 77 K. A significant rise in the BET surface area, total pore volume and micropore volume (textural parameters) occurred for all of the pristine chars after the activation process. Fast CO2 sorption kinetics (saturation reached in 3 mins.) and CO2 uptakes of up to ca. 6 wt. % have been measured by thermogravimetric analysis (TGA) at 35 ºC and 1 atm. The activated carbons (ACs) thus synthesised showed competitive performances compared to a commercial AC standard. Although the sorbents’ performances decreased at higher temperatures, they were easily regenerated after the capture stage

Simulating neutron radiation damage of graphite by in-situ electron irradiation

Radiation damage in nuclear grade graphite has been investigated using transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS). Changes in the structure on the atomic scale and chemical bonding, and the relationship between each were of particular interest. TEM was used to study damage in nuclear grade graphite on the atomic scale following 1.92×108 electrons nm-2 of electron beam exposure. During these experiments EELS spectra were also collected periodically to record changes in chemical bonding and structural disorder, by analysing the changes of the carbon K-edge. Image analysis software from the 'PyroMaN' research group provides further information, based on (002) fringe analysis. The software was applied to the micrographs of electron irradiated virgin 'Pile Grade A' (PGA) graphite to quantify the extent of damage from electron beam exposure

Maleated high oleic sunflower oil-treated cellulose fiber-based styrene butadiene rubber composites

Surface treatment of cellulose fibers was performed with maleated high oleic sunflower oil (MSOHO). The MSOHO-treated cellulose fibers and unmodified cellulose fibers were dispersed in styrene butadiene rubber (SBR) using a two roll mill. Vapor grown carbon nanofibers (VGCNF) were also incorporated at only one parts per hundred rubber (phr) in unmodified cellulose fibers/SBR composites. The curing characteristics, mechanical properties, and water absorption of the resulting composites were determined. MSOHO-treated fibers completed curing at much slower rate and also decreased the cure density of composites, compared to unmodified fibers. In contrast, the combination of VGCNF and unmodified cellulose fibers accelerated the SBR curing process, but reduced the cure density. MSOHO treatment improved the dispersion of the fibers in the SBR, which resulted in improved mechanical properties of composites. The composite incorporating 1 phr VGCNF and 15 phr unmodified cellulose fibers showed the greatest increase in tensile strength as compared with neat SBR

Eco-friendly synthesis of selective CO2 sorbents for post-combustion capture: The key role of basicity

Selective CO2 sorbents were successfully synthesized through carbonisation and physical (CO2) activation of oak wood. ACs thus synthesized along with a commercial carbon (GAC) included for comparison purposes were tested for CO2 capture. Under pure CO2 and 35 °C, although having much lower surface areas (highest SBET = 627 m2/g), oak wood-derived carbons exhibited similar uptakes as those achieved by the commercial AC (SBET = 1231 m2/g). On the other hand, upon changing to post-combustion conditions (ca. 53 °C, 15 % CO2/85 % N2), oak wood-based sorbents exhibited as large as (OW250PA) or even greater (OW800PA) sorption capacity than the commercial AC. The higher selectivity shown by oak wood derivatives was associated with their substantial amount of Ca-based inorganic fraction (up to nearly 12 wt. % for OW800PA), evidently related to their outstanding basicity (up to 93 % for OW800PA). Conversely, commercial AC is characterized by a negligible inorganic content (less than 1 wt. %) and lower basicity (ca. 67 %). Accordingly, it was proved that under post-combustion conditions the contribution of a more favoured (basic) surface chemistry outweighs the texture effect. Basic functionalities ensured stronger interactions with the carbon dioxide molecule, therefore implying a more selective sorption at lower gas concentration. Moreover, sorbents selectivity toward CO2 was obtained exploiting the advantageous properties (basicity) of the raw precursor rather than applying expensive and environmentally unsustainable chemical treatments