Altering the characteristics of carbon foams synthesized by biomass liquefaction with bio-oil addition: influence of the

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(2020) 5:53

ORIGINAL PAPER

Altering the characteristics of carbon foams synthesized by biomass liquefaction with bio‑oil addition: influence of the surfactant ratio Adife Seyda Yargic1   · Nurgul Ozbay1  Received: 8 April 2020 / Accepted: 22 July 2020 © Springer Nature Switzerland AG 2020

Abstract Carbon and graphite foams have recently been reported to be highly suited to a range of applications, such as high-temperature insulation, fuel cell electrodes, heat exchangers, brake discs, engine parts, and bone surgery materials. In this study, the effect of surfactant amount added during carbon foam synthesis on the structure of the foam produced through the liquefaction of spruce tree sawdust in the presence of pyrolytic oil (bio-oil) was studied. When a mixture of phenol and pyrolytic oil was used as a solvent during synthesis instead of just phenol, the foaming agent could not exit the polymer, leading to the production of a hard polymeric structure. Also, applying the standard amount of surfactant meant that the gas molecules could not overcome the high surface tension at the polymer surface and were therefore trapped within the polymer, causing relatively few pores to be generated during synthesis. Increasing the amount of surfactant led to successful foaming, as gas molecules could dissociate from the structure by overcoming the surface tension of the polymer matrix. When the combination of pyrolytic oil and phenol was utilized, adding extra surfactant caused the porosity to increase by 19–33% due to the 39–61% rise in the surface area, although the compressive strength of the foam decreased by 24–79%. This study, therefore, showed that the surface area, porosity, compressive strength, elemental carbon content, and crystalline structure of the carbon foam could be tailored to the application area of the foam by adjusting the conditions applied during synthesis appropriately. Keywords  Biomass/solvent ratio · Carbon foam · Solvolytic liquefaction · Pyrolysis · Spruce tree sawdust · Surfactant effect

Introduction The foaming greatly increases the technological utility and applicability of most traditional solids, such as polymers, metals, and ceramics. The properties of foam materials can vary markedly depending upon the precursor and production methods used, as these determine the porosity, the pore shape and size distributions in the foam (Prauchner et al. 2005). The first carbon foams were synthesized by W. Ford in the early 1960s by pyrolyzing a thermosetting polymer foam (Ford 1964; Wang et al. 2006). The resulting foams had similar cell sizes and good mechanical properties. Communicated by Mohamed Ksibi, Co-Editor in Chief . This paper was selected from the 2nd Euro-Mediterranean Conference for Environmental Integration (EMCEI), Tunisia 2019. * Nurgul Ozbay [email protected] 1



Chemical Engineering Department, Engineering Faculty, Bilecik Seyh Edebali University, 11210 Bilecik, Turkey

However, carbon materials with nongraphitized structures have disadvantages. These issues can be solved by