A great challenge mankind faces as it enters the twenty-first century is the management of waste (Xiong et al,2012), for example, textile waste and agro-waste. A good illustration of agro-waste is from banana plants. Banana plants are a crucial fruit crop in the world yet only 12% w/w is edible (Yu et al,2013). The non-edible parts like the pseudostems are discarded as agricultural waste (Yu et al,2013). Textile waste can originate when manufacturing clothes whereby the excess are buried or burned which could then lead to environmental pollution (Xiong et al,2012). Producing cellulose nanocrystals is an interesting and use for cotton and banana pseudostems. Cotton consist of the highest cellulose content of the plants with about 90% cellulose as compared to wood which consist of aboutCellulose is the most copious biopolymer on earth (Grishkewich et al,2017) that can be found in plants such as wood and cotton (Börjesson&Westman,2015). One of the most significant characteristics that parts cellulose from other biopolymer is that each of its glucose unit bears three hydroxyl groups as depicted in Figure 1 that ensures nanocellulose with a reactive surface containing numerous active hydroxyl groups (Dufresne&Lin,2014). Due to the linear structure and the presence of hydroxyl group, it can form an ordered crystalline structure held by hydrogen bonds (Espinosa et al,2013) as shown in Figure 2. Cellulose is also a fibrous, tough, water-insoluble substance which is essential to ensure the preservation of structure of natural fibres (Trache et al,2017). 40-50% cellulose (Börjesson&Westman, 2015).However, the extraction of cellulose nanocrystals (CNCs) from these natural resources requires the removal of non-cellulosic components such as lignin, pectin, hemicellulose and wax (Leung et al,2011). Common methods that are used to construct and aggregate CNCs require more tedious steps and treatments as it needs a pure cellulosic starting material (Leung et al,2011). Herein, a more straightforward method is used to produce nanocrystals by using Ammonium persulfate (APS). This oxidant is shows long term toxicity, high water solubility and low cost (Leung et al,2011). Based on research, even if using Ammonium persulfate is a much simpler procedure, it is still able to produce high quality cellulose nanocrystals that is more thermally stable.
CNCs have surfaced as a new class of nanomaterials for polymer reinforcement and nanocomposite composition with their outstanding high mechanical strength (modulus of 100-140 Gpa), low density (1.6 g cm-3), chemical tunability and low cost (Leung et al,2011). In addition, CNCs is flexible for chemical modification which may include converting them to carboxylic acid, amine, aldehyde or thiol groups that leads to further modifications. (Grishkewich et al,2017)