Preparation and Characterization of Orange Peels for Commercial Plastic: A Review
Nur Farhana Fadzil1, Siti Amira Othman2*
1 Fa culty of Science a nd Technology, Universiti Sa ins Isla m Ma la ysia , 71800, Nila i, Negeri Sembila n
2Fa culty of Applied Sciences a nd Technology, Universiti Tun Hussein Onn Ma la ysia , 84600, Pa goh, Johor
*Corresponding Author: sitia mira @uthm.edu.my
Accepted: 20 April 2021 | Published: 1 Ma y 2021
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Abstract: The synthetic plastic made by petroleum-based resources are commonly used by the society for their daily activities such as shopping bags, food packaging and drinking bottles.
These plastics ease our daily task, however the arising amounts of their waste lead to the overloading in land and affect the environment and ecosystems due to their non-biodegradable properties. On the other side, orange juice production generates about 50-60%of residues from initial the mass that are underutilized. The orange wastes constitute a valuable bioactive compound such as pectin and cellulose, potential for bioplastic application. Thus, orange peels reinforced by the epoxy composites are investigated for the production of bio-based polymer utilized ferrite magnetic powder as filler.
Keywords: orange peels, bioplastic, ferrite magnetic powder
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1. Introduction
Polymer, the first human-made plastic was made by Alexander Parkes in 1862. The cellulose consists in it enabled it to be molded and shaped into variety of shapes. Synthetic polymer has longer atoms chain compared to natural which makes it more flexible and moldable. It was then being proposed at Great International Convention in London and commercially recognized. Then the first fully synthetic come onto the scene in 1907 called Bakelite, derived from fossil fuel. Presently, these synthetic polymers are widely used in military, medical equipment and food industries for packaging and wrapping due to their diverse advantages offer including inexpensive, light-weight, excellent flexibility, heat-sealable and long-lasting (A.Bakar & Othman, 2019). However, these advantages also come together with great drawbacks. Plastics take many years to decomposed and non-renewable, released toxic substances, drain’s blockages during stormwater and giving threats to human and animals. In addition, these polymers are the major items in litter system which lead to detrimental environment effect and indirectly affected the country’s economy.
One of the best solutions to overcome this situation is by reducing the synthetic polymer and promoting new version of plastic, biopolymer. Bio-based polymer or bioplastic is a man-made or man-processed polymer using natural resources. It can be classified into two, natural bio- based polymer and synthetic polymer. Natural polymer made from protein and polysaccharides in biomass waste (Marichelvam & Jawaid, 2019). These bioplastics research and development are still ongoing and currently several biowaste such corn, rice starch, banana peels (Vishnu et al., 2018), and coffee have been used for this purpose.
Orange is a citrus fruit consumed in a large amount and quantities worldwide naturally, peeled form or as a juice. The nutrients confined in it including vitamin C, A and B, minerals (calcium, phosphorous, potassium), dietary fibers and several phytochemicals. Orange peels is one of the most underutilized and geographically biowaste residues due to the fact that the orange juice extraction only accounts for 50% of the original fruit mass. Pulp, seeds, peels and membrane residues are the major remaining dry waste after the juice pressing process. The peels and membrane of these orange residues embraced valuable polysaccharides such as pectin, cellulose and hemicellulose. Originates from the pulp are mono- and disaccharides in the form of soluble sugars (glucose, fructose and sucrose). However, they may cause environmental damages due to its relatively low pH and high content of water and organic mat ter if they are not treated accordingly despite its beneficial content. Cellulose is a vital structural component in primary cell of green plants. It is confined in orange peels which shows high molecular chain length or degree of polymerization. This high chain length associates with high tensile strength.
Study also shows that cellulose is more crystalline compared to starch. Hence, it capable to withstand higher temperature before become amorphous in water.
2. Experimental
Preparation of Orange Peels Biofilm
There are several steps needed for the preparation of orange peels biofilm. The orange peels obtained need to wash and soak in tap water overnight until it bland, in order to remove any unwanted substances such as dirt and soluble sugars contained in the orange peels. A study shows that, the surface of film was heterogenous and cracked if the soluble sugars were not removed (Bátori et al., 2017). Moist orange peels were cut into smaller pieces and dried for several days. The dried orange peels turn into powder form by grinding or milling it using electronic blender or ball mill grinder (Marsi et al., 2019). Solution casting method is used for the production of orange peels-based biofilm by mixing the liquid form of epoxy resin and hardener together with the orange peels powder. The mixture is stirred for few minutes to ensure the phase distribution of epoxy and the orange peels powder. The bio-composite mixture was poured into plastic plates or aluminium tray and left under UV for several d ays until it is completely dried and solidified.
Figure 1: Illustrates the procedures for orange peels waste extraction into biofilm
Magnetic powder as filler in bioplastic composite
The new era of plastic or packaging materials is the nanocomposite film which is the combination of biopolymer and nanofiller. The facts that biopolymers are known to be high availability and excellent biodegradability, however they are poor in mechanical properties and high permeability of water vapors lead to incompetent quality compared to conventional synthetic polymer. Knowing the facts, these drawbacks can be overcome by blending together different biopolymers. The second promising method is cross-linking of biopolymers films with diverse nanofillers. Interaction between biopolymer and nanofiller such as ferrite magnetic powder, modified the polymer matrix thus, contribute to the mechanical strength,
SUGAR
REMOVAL DRYING MILING MIXING CASTING
antimicrobial and antioxidants properties, thermal stability and barrier properties (Jamróz et al., 2019).
Figure 2: The figure illustrates the mechanisms for nanomaterials as reinforcement in biopolymers matrix.
Magnetic response material is an area of high interest nowadays due to their unique potential breakthrough application in biomedical (biosensor, active diagnosis drug delivery and engineering of tissue), microelectronic (electromechanics and actuators) and coatings (smart packaging, textiles and fibers). Research by Thevenot et al. in 2013 classified the responses of magnetic nanoparticles in polymer composite into three; (a) deformation ability upon exposure to magnetic field such as bending, rotation and stretching, (b) magnetic guidance (tendency to remotely move them to targeted area). It is particularly encouraging for cell and biomolecule separation and guidance in biomedical field (c) make used of magnetic induction as thermoresponsive actuator in polymer materials that being proven in drug release controller and shape memory devices.
3. Characterization Orange Peels Bioplastic
Thermal Analyses
Information on the properties of the chemical film such as decomposition obtained by thermogravimetric analysis (TGA) while thermal properties analysis determined using differential scanning calorimetry (DSC). Fehlberg et al in 2020 studied the effect of orange peels’ zest and particle size on degradation temperature to identify their impacts on processing of composite. Form the research, the zest’s component has low thermal stability compared to the white spongy part of the orange peel (albedo). As a result, the orange peels are more resistant to high temperature by removing the zest components. Besides, the elimination of zest from the OPs lead to lower water content due to the presence of water in the zest. The formation of plastic composites will exhibit better thermal stability and low material loss at 150°C, without the presence of zest in the orange peels (Fehlberg et al., 2020).
Surface Morphology
FESEM imaging allows the study of surface morphology and transversal section of the biofilm.
A study Batori et al (2017) reveal that, different methods of orange peels drying results in vary of biofilm surface structure. Orange peels consists of a complex mixture of dissolved and undissolved polymers. A phenomenon known as ‘self-stratification’, where one particle end on top of other, commonly occurs in drying films. Second layer exists on the surface by oven drying (OD) instead of incubator drying (ID) where smooth and uniform surface forms. This is due to continuous rotation prevent formation of clear pores in the biofilm and result in homogenous materials (Bátori et al., 2017).
Figure 3: Images from FESEM imaging of (a) OD, (b) ID and transversal section of the orange peels biofilm (c) and (d) [9].
Mechanical Strength
The properties of orange peels reinforced the polymer by increasing the tensile strength (Raghavendra, 2012). Orange peels particulates are substance with low density. Reported in a study, the increasing of orange peels fiber weight percentage and mesh size leads to the decreasing of material density. 200 mesh size of orange powder stated as their optimum density. Besides, rise in fiber volume leads to high percentage of void in the sample result in dip density. Indirectly, increased in density brings to more strength by enhances the material compactness (Awasthi & Saxena et al., 2019).
Higher concentration of orange peels, increased the tensile strength where 60% concentration shows excellent matrix bonding between them. Study proved that higher strength can be obtained by using smaller particles sizes. This is because, smaller size of filler and more regular shapes have the capability to pack up closer thus improving the ability to transf er stresses in the composite. Equal distribution of void in the lattice should be considered as it will lead to better tensile strength performance.
Biodegradability test
The key features of the orange peels biofilm are their biodegradability. Therefore, anaerobic digestion test is performed to determine their ability to decompose compared to synthetic polymer. Research by Batori et al in 2017, proven the orange peels biofilm capability by reaching 90% degradation within 15 days as shown in Table 1.
Table 1: Degradation (%) of the biofilm in oven drying (OD) and incubator drying method (ID) by days [9].
4. Conclusion
The employment of orange peels-based polymer for the production of commercial plastic are evolving as suitable replacement for conventional synthetic polymer. The bio-based films show degradable under anaerobic activity. The bioactive compound constitutes in the orange peels such as pectin and cellulose enable the biofilm to decompose as important as the strength and short-live packaging materials. The insertion of magnetic powder in the bio-composite offers an interesting deformation characteristic and enhance the mechanical strength of the bio- polymer film.
Acknowledgement
The authors would like to thanks the Universiti Tun Hussein Onn Malaysia for facilities provided.
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