Graphene oxide and graphene fiber produced by different nozzle size, feed rate and reduction time with vitamin C

Abstract

The processing conditions of graphene oxide and graphene fibers are important for final fiber properties. The effect of different processing conditions such as feed rate, nozzle size (length and diameter), and reduction time by vitamin C on fiber properties such as morphology, mechanical properties and electrical conductivity has been analyzed. It has been observed that at the constant feed rates, increase in nozzle length results in higher mechanical properties. For the samples produced with long nozzle, thinner nozzle results to higher mechanical properties than thicker one. Decrease in nozzle length and increase in feed rate and reduction time by vitamin C resulted in an increased crimpy structure of fiber surface. Higher fiber strength was observed when the reduction time was decreased. The increase in the feed rate resulted in an increase of fiber linear densities (tex). All fibers experimented were in the semiconductor range. In this study, it has been seen that short, thin nozzles with 10 ml/h feed rate and reduction with 2.5 h provided better mechanical properties along with electrical conductivity.

The effect of oxidation process on graphene oxide fiber properties

“…Furthermore, less reaction time (24 hour) for fibers obtained with PH results in less functional groups on the flake surface which is also confirmed by XPS spectroscopy. Less functional groups may lead to collapsed, porous and crimpy structure, since reduction studies which have been performed to reduce functional groups pointed out that an increase of reduction time results in more crimped surface structure [13,14]. GO fiber linear density The fiber linear density (Tex) , which is the weight in grams of 1000 meters of GO fibers, for three prepared samples are shown in Table 2.…”

“…As can be seen in Table 2, the fiber linear density of the fibers produced with MH is the highest, and it decreased when the pre-oxidation step was applied. Pre-oxidation process may lead to deterioration of graphene flakes, resulting in smaller graphene flake diameter and mass loss [13][14][15]. By using the modified Hummers method, the functional groups increased as can be seen from the XPS spectroscopy results which may lead to an increase of weight with less material loss than that observed for pre-oxidized samples.…”

“…On the other hand, pre-oxidation process may lead to formation of smaller graphene flakes and material loss [13][14][15], resulting in lower breaking strength and breaking elongations.…”

“…When pH level reached 5 to 6, the pre-oxidized graphene particles remainding at the bottom were left to dry. Afterwards, graphite oxide was produced according to the Hummers method [10]. In this method, preoxidized graphite with NaNO 3 and H 2 SO 4 were stirred uniformly in an ice bath with a magnetic stirrer for 10 min.…”

“…All of these methods have been developed to obtain graphene oxide (GO) particles from graphite, and those methods focused on examining the effect of production parameters on final graphene oxide particle properties without conversion into GO fiber. In this study, for the first time, the authors investigated the effect of oxidation methods (Hummers, modified Hummers and pre-oxidized modified Hummers methods) on resultant GO fiber properties, while the studies performed previously focused on determining the effect of processing conditions such as nozzle size, feed rate and reduction time with Vitamin C, and the effect of coagulation time, number of coagulation baths and ingredients on resultant graphene oxide fiber properties [10,11]…”