Comparative evaluation of mechanical properties, scanning electron microscopy (SEM) analysis, and water holding capacity of recycled and virgin high-density polyethylene (HDPE) plastics: a study on the morphological and physical characteristics of thermoplastic materials
Keywords:
Municipal solid waste, Recycling, High density polyethylene plastic, Tensile test, Impact strength, Rockwell hardness numberAbstract
Municipal solid waste management when poorly done serves as a breeding ground for pathogens which cause loss of arable land and diseases directly or indirectly. In a bid to combat the geometrical increase in waste conditioned by the subsequent increase in human population, recycling has become a solution. One major throwback to recycling is the belief that due to the thermal decomposition of plastic, the recycled product would have different properties from that of the original plastic product hence rendering its suitability for use in production invalid. This research evaluated the recycling process of High Density Polyethylene (HDPE) plastic and carried out mechanical property characterization tests which included tensile test, hardness test and impact test on the recycled HDPE product. 200g of HDPE plastic was used as specimen melted in a furnace and poured into a wooden mold to cool. The cooled material was subjected to tensile, impact and hardness tests. The test exposed that the Rockwell Hardness Number (RHN) for the examined HDPE material was given as 50.0mm. The tensile test was evaluated to be 25.60MPa. The sample had an impact test value of 284J/m2. It was also determined that the sample had a yield strength of 21.412MPa. The mechanical properties of hardness number, tensile strength, impact strength and yield stress of an original un-recycled HDPE plastic material are given respectively as (60.0-70.0mm), (21.4–30.3)MPa, (158–505 J/m2) and (17.9–31.0)MPa respectively. The water absorption test revealed that the % absorption from the virgin and recycled HDPE plastics were 0.015% and 0.027% respectively. The high value of the recycled HDPE owing to the presence of additives and impurities. Comparison of these properties between un-recycled (virgin) and recycled HDPE plastic show that the values gotten are within the acceptable range and hence, recycled HDPE plastic is very suitable for use in production as its mechanical characteristics are similar to that of un-recycled HDPE plastic.
References
Lu, N., & Oza, S. (2013). A comparative study of the mechanical properties of hemp fiber with virgin and recycled high density polyethylene matrix. Composites part b: Engineering, 45(1), 1651–1656. https://doi.org/10.1016/j.compositesb.2012.09.076
Lee, S. T., & Park, C. B. (2014). Foam extrusion: Principles and practice. CRC press. https://b2n.ir/j48268
Amin, S., & Amin, M. (2011). Thermoplastic elastomeric (TPE) materials and their use in outdoor electrical insulation. Reviews on advanced materials science, 29(1), 15–30. https://www.academia.edu/download/51899123/02_amin.pdf
Xu, M., Xu, Z., Zhang, Z., Lei, H., Bai, Y., & Fang, D. (2019). Mechanical properties and energy absorption capability of AuxHex structure under in-plane compression: Theoretical and experimental studies. International journal of mechanical sciences, 159, 43–57. https://doi.org/10.1016/j.ijmecsci.2019.05.044
Aurrekoetxea, J., Sarrionandia, M. A., Urrutibeascoa, I., & Maspoch, M. L. (2001). Effects of recycling on the microstructure and the mechanical properties of isotactic polypropylene. Journal of materials science, 36, 2607–2613. https://doi.org/10.1023/a:1017983907260
Imran Khan, M., Zagho, M. M., & Shakoor, R. A. (2017). A brief overview of shape memory effect in thermoplastic polymers. In Smart polymer nanocomposites: energy harvesting, self-healing and shape memory applications (pp. 281–301). Springer. http://dx.doi.org/10.1007/978-3-319-50424-7_10
Mishra, J. K., Hwang, K. J., & Ha, C. S. (2005). Preparation, mechanical and rheological properties of a thermoplastic polyolefin (TPO) organoclay nanocomposite with reference to the effect of maleic anhydride modified polypropylene as a compatibilizer. polymer, 46(6), 1995–2002. https://doi.org/10.1016/j.polymer.2004.12.044
de Carvalho, G. M., Muniz, E. C., & Rubira, A. F. (2006). Hydrolysis of post-consume poly (ethylene terephthalate) with sulfuric acid and product characterization by WAXD, 13C NMR and DSC. Polymer degradation and stability, 91(6), 1326–1332. https://doi.org/10.1016/j.polymdegradstab.2005.08.005
Nichols, C. Moore, T. Griffith, S. (2004). Slow-crystallizing polyester resins. https://patents.google.com/patent/wo2004104080a1/en
Pascault, J. P., & Williams, R. J. (2013). Thermosetting polymers. Handbook of polymer synthesis, characterization, and processing, 519-533. https://doi.org/10.1002/9781118480793.ch28
Olah, G. A., Goeppert, A., & Prakash, G. S. (2009). Chemical recycling of carbon dioxide to methanol and dimethyl ether: From greenhouse gas to renewable, environmentally carbon neutral fuels and synthetic hydrocarbons. The journal of organic chemistry, 74(2), 487–498. https://doi.org/10.1021/jo801260f
Ribeiro, M. C. S., Fiúza, A., Ferreira, A., Dinis, M. D. L., Meira Castro, A. C., Meixedo, J. P., & Alvim, M. R. (2016). Recycling approach towards sustainability advance of composite materials’ industry. Recycling, 1(1), 178–193. https://doi.org/10.3390/recycling1010178
Van Krevelen, D. W., & Te Nijenhuis, K. (2009). Properties of polymers: Their correlation with chemical structure; their numerical estimation and prediction from additive group contributions. Elsevier. https://b2n.ir/k94327
Rodriguez, F., Cohen, F., Ober, C. K., & Archer, L. (2003). Principles of polymer systems. CRC Press. https://doi.org/10.1201/b12837
s Shih, L. H. (2001). Reverse logistics system planning for recycling electrical appliances and computers in Taiwan. Resources, conservation and recycling, 32(1), 55–72. https://doi.org/10.1016/s0921-3449(00)00098-7
Kolek, Z. (2001). Recycled polymers from food packaging in relation to environmental protection. Polish journal of environmental studies, 10(1), 73–76. https://www.pjoes.com/pdf-87356-21215?filename=recycled polymers from.pdf
Giboz, J., Copponnex, T., & Mélé, P. (2007). Microinjection molding of thermoplastic polymers: a review. journal of micromechanics and microengineering, 17(6), R96. https://doi.org/10.1088/0960-1317/17/6/r02
Liu, H., Zhang, W., Chen, H., & Chen, Z. (2024). Damage analysis and mechanical performance evaluation of frame structures in recycling. In Structures (Vol. 66, p. 106906). Elsevier. https://doi.org/10.1016/j.istruc.2024.106906
Wu, C., Zhang, S., Wu, W., Xi, Z., Zhou, C., Wang, X., ... & Chen, D. (2019). Carbon nanotubes grown on the inner wall of carbonized wood tracheids for high-performance supercapacitors. Carbon, 150, 311–318. https://doi.org/10.1016/j.carbon.2019.05.032
Alzerreca, M., Paris, M., Boyron, O., Orditz, D., Louarn, G., & Correc, O. (2015). Mechanical properties and molecular structures of virgin and recycled HDPE polymers used in gravity sewer systems. polymer testing, 46, 1–8. https://doi.org/10.1016/j.polymertesting.2015.06.012
Rahman, M. T., Hoque, M. A., Rahman, G. T., Gafur, M. A., Khan, R. A., & Hossain, M. K. (2019). Evaluation of thermal, mechanical, electrical and optical properties of metal-oxide dispersed HDPE nanocomposites. Materials research express, 6(8), 85092. https://doi.org/10.1088/2053-1591/ab22d8
Awad, A. H., El Gamasy, R., Abd El Wahab, A., & Abdellatif, M. H. (2019). Mechanical and physical properties of PP and HDPE. Eng. sci, 4(2), 34. https://doi.org/10.11648/j.es.20190402.12
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