Carbamate Process


The present invention aims to produce cellulose carbamate (CC) via carbamate synthesis under microwave irradiation and hydrothermal conditions. The CC was reinforced with graphene oxide (GO) to fabricate homogeneous CC-GO membranes using a simple solution-mixing method. 


The annual production of lignocellulosic materials was roughly 200 billion metric tons worldwide and had great potential as a cheap and renewable feedstock for different applications compared to other synthetic fibre. The chemical treatment on lignocelluloses using alkali or acid hydrolysis will cause the reducing end group to peel into glucose or random glycosidic bond cleavage that shortens the cellulose chain. Hence, carbamate synthesis was carried out to improve solubility by changing the chemical bonding of cellulose.


Cellulose does not have potential applications because it is hard to be dissolved in a common and cheaper solvent. This is due to fibrils’ structure, which has high crystallinity and the presence of inter- and intra- hydrogen-bonding molecules. Besides that, the high degree of polymerization of cellulose is attributed to the difficulty in cellulose dissolution. Although cellulose is a hydrophilic material, the presence of a large number of hydrogen bonds that group cellulose chains together in a network results in the difficulty of cellulose dissolution in an aqueous solution.


CC is easier to be dissolved in an aqueous alkaline/urea solvent, which requires no further treatments to enhance biological membrane/hydrogel. In addition, the produced membrane/hydrogel is structurally robust and efficient to work as a mobile carrier due to its smaller symmetrical pore size – avoiding the seepage of added materials.


In practical and industrial, the CC is a potential alternative for viscose process as it is proven can be dissolved in cellulose solvent system and further processed through viscose spinning machines to produce regenerated membrane and fiber. Moreover, the end product of CC can be produced from cellulose dissolution in alkaline aqueous solution or conventional organic solvents, followed by spinning or extruding process similar to the viscose manufacturing process. Hence, the CC can be synthesized on an industrial scale in a central location and can be shipped to decentralize facility for further processing to form products. 


In decades, the increasing environmental friendliness regulations and the soaring prices of petroleum-based polymers have attracted the great attention of scientists and engineers, either in academic or industrial areas. These cellulose-modified chemistry techniques transform chemical compounds, and this is to enable it to be applicable in the commercial industry and extend the application of cellulosic material. Cellulose derivatization is to reshape the cellulose from its natural form, modify its chemical and/or physical properties, and make cellulose amenable to analysis by a specific analytical methodology.


For agriculture, medical, wastewater treatment and industrial applications such as plastic mulch, packaging fil, bio membrane, potting soil, contact lens, luminescent hydrogel, self-healing hydrogel, wound dressing, etc.

TRL :  4