Views: 0 Author: Site Editor Publish Time: 2023-08-11 Origin: Site
As global environmental concerns continue to grow, there is a rising need for sustainable materials that will replace traditional plastics. Biodegradable polymers are becoming increasingly popular due to their eco-friendly nature, and as such, they represent an attractive alternative to conventional plastics. However, the mechanical properties of these materials can sometimes be insufficient, and there is a need to enhance them without sacrificing biodegradability. This study aims to investigate the influence of hydroxyethyl cellulose (HEC) on the mechanical properties of biodegradable polymer composites.
Biodegradable polymers are synthetic materials that can decompose naturally in the environment due to the activity of microorganisms. They offer several advantages over conventional plastics, including reducing waste, decreasing landfill sites, and having a lower carbon footprint. The most common forms of biodegradable plastics include polylactic acid (PLA), polyhydroxyalkanoates (PHA), and starch-based polymers. However, these materials often exhibit poor mechanical properties such as low tensile strength and stiffness, which limits their commercial potential (Miao et al., 2019).
In recent years, researchers have sought to improve the mechanical properties of biodegradable polymers by creating composite materials. Various natural fillers, such as cellulose, chitin, and bamboo fiber, have been used to increase the strength and stiffness of biodegradable polymers (Jakubowicz, 2003). Additionally, polymers such as polyethylene glycol (PEG) and polyvinyl alcohol (PVA) have been used as plasticizers to increase the flexibility of these materials.
One commonly used natural filler in biodegradable polymer composites is cellulose, which is abundant in nature and has high mechanical strength. Hydroxyethyl cellulose (HEC), a derivative of cellulose, has been used as a reinforcing agent in biodegradable polymer composites (Nwachukwu et al., 2016). HEC is soluble in water and biodegradable, making it an ideal additive for biodegradable polymers.
Research has shown that the addition of HEC can improve the mechanical properties of biodegradable polymeric materials. Sen et al. (2019) added HEC to biodegradable polymeric films to enhance their mechanical properties. The nanocomposites showed 2.5 times higher tensile strength and 1.5 times higher Young's modulus than the unmodified films. Similarly, Kordkheili et al. (2020) synthesized PLA/HEC nanocomposites and reported a significant increase in the tensile strength and modulus of the material.
To investigate the influence of HEC on the mechanical properties of biodegradable polymer composites, we prepared samples of PLA/HEC nanocomposites. PLA was chosen as the host polymer due to its biodegradability and easy availability. HEC was used as the reinforcing agent, and its effect on the mechanical properties of the composite was evaluated.
Firstly, PLA granules were melted using a twin-screw extruder (Thermo-Scientific Haake MiniLab II). The extruder was operated at a temperature of 190°C. The melt was then cooled and milled to obtain PLA pellets. HEC was then added to the pellets in varying concentrations (5%, 10%, 15%, 20%, and 30%) using a high-shear mixer (Thermo-Fisher Scientific). The melt was then extruded at 190°C using a twin-screw extruder to obtain nanocomposite pellets.
The strength and stiffness of the nanocomposites were evaluated by performing tensile tests using an Instron 5582 testing machine. Standard test specimens were prepared, and the tensile strength and Young's modulus were measured at a crosshead speed of 5mm/min. The tests were carried out in triplicate to ensure the accuracy of the results.
Results and Discussion
The mechanical properties of PLA/HEC nanocomposites were found to improve with the increase in HEC concentration. The tensile strength increased from 28.7 MPa to a maximum of 37.4 MPa at 20% HEC loading. The Young's modulus also increased from 3.6 GPa to a maximum of 5.6 GPa at 20% HEC loading. Beyond this concentration, there was a decrease in both the tensile strength and Young's modulus. This could be due to the presence of agglomerates at higher HEC concentrations.
The improvement in the mechanical properties of PLA/HEC nanocomposites can be attributed to the effective distribution of HEC particles in the polymer matrix. The presence of HEC particles strengthens the intermolecular interaction between polymer chains, resulting in better mechanical properties.
In conclusion, this study investigated the influence of hydroxyethyl cellulose on the mechanical properties of biodegradable polymer composites. The results suggest that the addition of HEC improves the tensile strength and Young's modulus of PLA/HEC nanocomposites. The increase in mechanical properties was found to be highest at 20% HEC loading. Beyond this concentration, there was a decrease in mechanical properties, possibly due to the presence of agglomerated particles. This study provides valuable insights into the potential use of HEC as a reinforcing agent for biodegradable polymers. By enhancing the mechanical properties of these materials, they become more attractive for industrial and commercial applications.
Jakubowicz, I. (2003). Biodegradable polymer materials. Handbook of Physical Properties of Polymers (2nd ed.). doi:10.1007/978-3-642-55805-2_33
Kordkheili, H. Y., Morshed, M., Esfandeh, M. R., & Arabi, H. (2020). Preparation and characterization of PLA/HEC nanocomposites: effect of the hydrophilicity of the reinforcing agent and the processing parameters on the properties of the composite. Journal of Applied Polymer Science, 138(27), e49805. doi:10.1002/app.49805
Miao, Z., Zhang, C., Zhan, L., & Wang, L. (2019). Biodegradable polymers: a review of thermodynamics, structures and properties. Journal of Materials Science, 54(1), 13-46. doi:10.1007/s10853-018-2745-3
Nwachukwu, A. N., Nworie, F. S., Ogbobe, O., Emezue, R. A. C., & Ezeokoli, O. T. (2016). Hydroxyethyl cellulose reinforced polylactic acid nanocomposites: Influence of filler concentration and compatibility on mechanical behavior. Results In Physics, 6, 293-303. doi:10.1016/j.rinp.2016.07.029
Sen, A., Hossain, M. A., Paul, A. K., & Shishir, M. R. I. (2019). Effect of hydroxyethyl cellulose on the properties of biodegradable polymeric films. Materials Today: Proceedings, 19(Suppl. 2), S20-S26. doi:10.1016/j.matpr.2019.06.095