PERTANIKA JOURNAL OF SCIENCE AND TECHNOLOGY

Processing of polymer composites employing fibres from sustainable sources as reinforcement has drastically grown in recent years. This research used Miswak fibres (MF) and polylactic acid (PLA) as the main materials for composite processing. Natural fibres typically include a hydroxyl group (-OH), which makes them hydrophilic. In contrast, the hydrophobic nature of polymer matrices causes them to naturally repel water. This problem was resolved by chemically altering the surface of natural fibres using a 2 wt% sodium hydroxide (NaOH) solution. In this paper, the effect of alkaline treatment has been proven by performing chemical analysis, tensile properties, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) to analyse the influence of treated MF content on composite characteristics. The results revealed that biocomposites with modified miswak fibres exhibited better properties than untreated miswak fibres-reinforced polymer biocomposites. Treated MF/PLA composites showed an increase in tensile strength of 52.9% and tensile modulus of 8.16%. From the chemical composition test, lignin composition was reduced from 5.09% to 3.06% and hemicellulose from 28.12 to 10.62% after MF was treated. Meanwhile, thermal properties for both TGA and DSC revealed the elimination of hemicellulose and lignin characteristic peaks, improving the thermal stability of the treated MF/PLA composite. Thus, compared to a pristine sample, the resultant composites'' higher mechanical strength and thermal stability demonstrated the significance of chemically treated natural fibres. The novelty of this research is the data on miswak fibre treatment, as no research has been found for this selected treated fibre.

• Abhary, M., & Al-Hazmi, A.-A. (2016). Antibacterial activity of Miswak (Salvadora persica L.) extracts on oral hygiene. Journal of Taibah University for Science, 10(4), 513-520. https://doi.org/10.1016/j.jtusci.2015.09.007

• Ageyeva, T., Kovács, J. G., & Tábi, T. (2021). Comparison of the efficiency of the most effective heterogeneous nucleating agents for Poly(lactic acid). Journal of Thermal Analysis and Calorimetry, 147(15), 8199-8211. https://doi.org/10.1007/s10973-021-11145-y

• Ahmad, H., & Rajagopal, K. (2014). Salvadora persica L. (Meswak) in dental hygiene. The Saudi Journal for Dental Research, 5(2), 130-134. https://doi.org/10.1016/j.sjdr.2014.02.002

• Alili, N., Türp, J. C., Kulik, E. M., & Waltimo, T. (2014). Volatile compounds of Salvadora persica inhibit the growth of oral Candida species. Archives of Oral Biology, 59(5), 441-447. https://doi.org/10.1016/j.archoralbio.2014.02.001

• Aliotta, L., Cinelli, P., Coltelli, M., Righetti, M. C., Gazzano, M., & Lazzeri, A. (2017). Effect of nucleating agents on crystallinity and properties of Poly (lactic acid) (PLA). European Polymer Journal, 93, 822-832. https://doi.org/10.1016/j.eurpolymj.2017.04.041

• Amoian, B., Moghadamnia, A., Barzi, S., Sheykholeslami, S., & Rangiani, A. (2010). Salvadora persica extract chewing gum and gingival health: Improvement of gingival and probe-bleeding index. Complementary Therapies in Clinical Practice, 16(3), 121-123. https://doi.org/10.1016/j.ctcp.2009.11.002

• Arbelaiz, A., Fernández, B., Ramos, J. A., Retegi, A., Llano-Ponte, R., & Mondragon, I. (2005). Mechanical properties of short flax fibre bundle/polypropylene composites: Influence of matrix/fibre modification, fibre content, water uptake and recycling. Composites Science and Technology, 65(10), 1582-1592. https://doi.org/10.1016/j.compscitech.2005.01.008

• Bakri, M. K., Jayamani, E., & Hamdan, S. (2017). Processing and characterization of banana fiber/epoxy composites: Effect of alkaline treatment. Materials Today: Proceedings, 4(2), 2871-2878. https://doi.org/10.1016/j.matpr.2017.02.167

• Chaaben, R., Taktak, R., Mnif, B., Guermazi, N., & Elleuch, K. (2020). Innovative biocomposite development based on the incorporation of Salvadora persica in acrylic resin for dental material. Journal of Thermoplastic Composite Materials, 35(11), 1815-1831. https://doi.org/10.1177/0892705720939167

• Chaurasia, A., Patil, R., & Nagar, A. (2013). Miswak in oral cavity - An update. Journal of Oral Biology and Craniofacial Research, 3(2), 98-101. https://doi.org/10.1016/j.jobcr.2012.09.004

• Cornelissen, T., Yperman, J., Reggers, G., Schreurs, S., & Carleer, R. (2008). Flash co-pyrolysis of biomass with polylactic acid. Part 1: Influence on bio-oil yield and heating value. Fuel, 87(7), 1031-1041. https://doi.org/10.1016/j.fuel.2007.07.019

• Corre, Y.-M., Maazouz, A., Duchet, J., & Reignier, J. (2011). Batch foaming of chain extended PLA with supercritical CO2: Influence of the rheological properties and the process parameters on the cellular structure. The Journal of Supercritical Fluids, 58(1), 177-188. https://doi.org/10.1016/j.supflu.2011.03.006

• Correia, C., Gomes, T. E. P., Gonçalves, I., & Neto, V. (2022). Reprocessability of PLA through chain extension for fused filament fabrication. Journal of Manufacturing and Materials Processing, 6(1), 26. https://doi.org/10.3390/jmmp6010026

• Das, M., & Chakraborty, D. (2006). Influence of mercerization on the dynamic mechanical properties of bamboo, A natural lignocellulosic composite. Industrial & Engineering Chemistry Research, 45(19), 6489-6492. https://doi.org/10.1021/ie0603971

• Ezeamaku, U. L., Onukwuli, O. D., Ezeh, M. E., Eze, I. O., Odimegwu, N. E., & Agu, C. P. (2022). Experimental investigation on influence of selected chemical treatment on banana fibre. Industrial Crops and Products, 185, 115135. https://doi.org/10.1016/j.indcrop.2022.115135

• Guillaume, G., Phillipe, E., & Luc, R. (2013). Twin-screw extrusin impact on natural fibre morphology and material properties in poly(lactic acid) based biocomposites. Industrial Crops and Products, 46, 173-185. https://doi.org/10.1016/j.indcrop.2013.01.026

• Hristov, V., & Vasileva, S. (2003). Dynamic mechanical and thermal properties of modified poly(propylene) wood fiber composites. Macromolecular Materials and Engineering, 288(10), 798-806. https://doi.org/10.1002/mame.200300110

• Hyvarinen, M., Jabeen, R., & Karki, T. (2020). The modelling of extrusion processes for polymers-a review. Polymers (Basel), 12(6), 1306. https://doi.org/10.3390/polym12061306

• Jia, S., Yu, D., Zhu, Y., Wang, Z., Chen, L., & Fu, L. (2017). Morphology, crystallization and thermal behaviors of PLA-based composites: Wonderful effects of hybrid GO/PEG via dynamic impregnating. Polymers (Basel), 9(10), 528. https://doi.org/10.3390/polym9100528

• John, M., & Thomas, S. (2008). Biofibres and biocomposites. Carbohydrate Polymers, 71(3), 343-364. https://doi.org/10.1016/j.carbpol.2007.05.040

• Karsli, N. G., & Aytac, A. (2014). Properties of alkali treated short flax fiber reinforced poly (lactic acid)/polycarbonate composites. Fibers and Polymers, 15(12), 2607-2612. https://doi.org/10.1007/s12221-014-2607-4

• Kuzmin, A. M., & Radaikina, E. A. (2020). Technology development for the production of thermoplastic composites with agricultural fillers by compounding method on co-directional twin screw extruder. IOP Conference Series:Materials Science and Engineering 290, 873, 012022. https://doi.org/10.1088/1757-899X/873/1/012022

• Li, X., Tabil, L. G., & Panigrahi, S. (2007). Chemical treatments of natural fiber for use in natural fiber-reinforced composites: A review. Journal of Polymers and the Environment, 15(1), 25-33. https://doi.org/10.1007/s10924-006-0042-3

• Marques, M. de F. V., Melo, R. P., Araujo, R. da S., Lunz, J. do N., & Aguiar, V. de O. (2014). Improvement of mechanical properties of natural fiber-polypropylene composites using successive alkaline treatments. Journal of Applied Polymer Science, 132(12), 41710. https://doi.org/10.1002/app.41710

• Mikulyonok, I. O. (2013). Equipment for preparing and continuous molding of thermoplastic composites. Chemical and Petroleum Engineering, 48(11), 658-661. https://doi.org/10.1007/s10556-013-9676-x

• Moawed, E. A. (2013). Effect of heating processes on Salvadora persica (Miswak) and its application for removal and determination of aniline blue from wastewater. Journal of Taibah University for Science, 7(1), 26-34. https://doi.org/10.1016/j.jtusci.2013.03.002

• Moawed, E. A., & Abulkibash, A. B. (2016). Selective separation of Light green and Safranin O from aqueous solution using Salvadora persica (Miswak) powder as a new biosorbent. Journal of Saudi Chemical Society, 20, S178-S185. https://doi.org/10.1016/j.jscs.2012.10.011

• Moser, K., Schmitt, M., Holzer, A., Bergmann, B., Diemert, J., & Elsner, P. (2016). Optimization of PLA compounds using novel nucleating agents and plasticizers. AIP Conference Proceedings, 1779(1), 060006-1-060006-5. https://doi.org/10.1063/1.4965527

• Mukherjee, T., & Kao, N. (2011). PLA based biopolymer reinforced with natural fibre: A Review. Journal of Polymers and the Environment, 19, 714-725. https://doi.org/10.1007/s10924-011-0320-6

• Murariu, M., & Dubois, P. (2016). PLA composites: From production to properties. Advanced Drug Delivery Reviews, 107, 17-46. https://doi.org/10.1016/j.addr.2016.04.003

• Nagarajan, V., Zhang, K., Misra, M., & Mohanty, A. K. (2015). Overcoming the fundamental challenges in improving the impact strength and crystallinity of PLA biocomposites: Influence of nucleating agent and mold temperature. ACS Appl Mater Interfaces, 7(21), 11203-11214. https://doi.org/10.1021/acsami.5b01145

• Nofar, M., Sacligil, D., Carreau, P. J., Kamal, M. R., & Heuzey, M. C. (2019). Poly(lactic acid) blends: Processing, properties and applications. International Journal of Biological Macromolecules, 125, 307-360. https://doi.org/10.1016/j.ijbiomac.2018.12.002

• Orue, A., Jauregi, A., Unsuain, U., Labidi, J., Eceiza, A., & Arbelaiz, A. (2016). The effect of alkaline and silane treatments on mechanical properties and breakage of sisal fibers and poly(lactic acid)/sisal fiber composites. Composites Part A: Applied Science and Manufacturing, 84, 186-195. https://doi.org/10.1016/j.compositesa.2016.01.021

• Pluta, M., Paul, M.-A., Alexandre, M., & Dubois, P. (2006). Plasticized polylactide/clay nanocomposites. I. The role of filler content and its surface organo-modification on the physico-chemical properties. Journal of Polymer Science Part B: Polymer Physics, 44(2), 299-311. https://doi.org/10.1002/polb.20694

• Rajesh, G., & Prasad, A. V. R. (2014). Tensile properties of successive alkali treated short jute fiber reinforced PLA composites. Procedia Materials Sciences 5, 2188-2196. https://doi.org/10.1016/j.mspro.2014.07.425

• Ramadan, K. S., & Alshamrani, S. A. (2016). Phytochemical analysis and antioxidant activity of Salvadora persica extracts. Journal of Basic and Applied Research in Biomedicine, 2(3), 390-395.

• Raquez, J.-M., Habibi, Y., Murariu, M., & Dubois, P. (2013). Polylactide (PLA)-based nanocomposites. Progress in Polymer Science, 38, 1504-1542. https://doi.org/10.1016/j.progpolymsci.2013.05.014

• Ray, D., Sarkar, B. K., Basak, R. K., & Rana, A. K. (2002). Study of the thermal behavior of alkali-treated jute fibers. Journal of Applied Polymer Science, 85(12), 2594-2599. https://doi.org/10.1002/app.10934

• Saini, P., Arora, M., & Kumar, M. N. V. R. (2016). Poly(lactic acid) blends in biomedical applications. Advanced Drug Delivery Reviews, 107, 47-59. https://doi.org/10.1016/j.addr.2016.06.014

• Sarasini, F. (2017). 4 - Thermoplastic biopolymer matrices for biocomposites. In D. Ray (Ed.), Biocomposites for High-Performance Applications (pp. 81-123). Woodhead Publishing. https://doi.org/10.1016/B978-0-08-100793-8.00004-1

• Satyanarayana, K. G., Arizaga, G. G. C., & Wypych, F. (2009). Biodegradable composites based on lignocellulosic fibers—An overview. Progress in Polymer Science, 34(9), 982-1021. https://doi.org/10.1016/j.progpolymsci.2008.12.002

• Savaş, S. (2018). Structural properties and mechanical performance of Salvadora persica L. (Miswak) reinforced polypropylene composites. Polymer Composites, 40(S1), E663-E677. https://doi.org/10.1002/pc.24939

• Sgriccia, N., & Hawley, M. (2007). Thermal, morphological, and electrical characterization of microwave processed natural fiber composites. Composites Science and Technology, 67(9), 1986-1991. https://doi.org/10.1016/j.compscitech.2006.07.031

• Shafi, A. R., Diyana, A. N., Abdan, K., & Salit, M. S. (2023). Effect of alkaline treatment on mechanical and thermal properties of Miswak (Salvadora persica) fiber-reinforced polylactic acid. Polymers, 15(9), 2228. https://doi.org/10.3390/polym15092228

• Shafi, A. R., , Abdan, K., Harmaen, A. S., Zaman, K., Isma, T., Liu, Q., & Lee, C. H. (2020a). Characterization study of empty fruit bunch (EFB) fibers reinforcement in poly (butylene) succinate (PBS)/starch/glycerol composite sheet. Polymers, 12(7), 1571. https://doi.org/10.3390/polym12071571

• Shafi, A. R., Abdan, K., Harmaen, A. S., Zaman, K., Nurrazi, N. M. , Isma, T., & Lee, C. H. (2020b). Effect of empty fruit brunch reinforcement in polybutylene-succinate/modified tapioca starch blend for agricultural mulch films. Scientific Reports, 10(1), 1166. https://doi.org/10.1038/s41598-020-58278-y

• Sherwani, S. F. K., Zainudin, E. S., Sapuan, S. M., Leman, Z., & Khalina, A. (2021). Physical, mechanical, and morphological properties of treated sugar palm/glass reinforced poly(lactic acid) hybrid composites. Polymers (Basel), 13(21), 3620. https://doi.org/10.3390/polym13213620

• Siakeng, R., Jawaid, M., Asim, M., Saba, N., M R, S., Siengchin, S., & Fouad, H. (2020a). Alkali treated coir/pineapple leaf fibres reinforced PLA hybrid composites: Evaluation of mechanical, morphological, thermal and physical properties. Express Polymer Letters, 14, 717-730. https://doi.org/10.3144/expresspolymlett.2020.59

• Siakeng, R., Jawaid, M., Asim, M., & Siengchin, S. (2020b). Accelerated weathering and soil burial effect on biodegradability, colour and texture of coir/pineapple leaf fibres/PLA biocomposites. Polymers (Basel), 12(2), 15. https://doi.org/10.3390/polym12020458

• Singh, M., & Singh, R. (2020). Twin screw extrusion for recycling of thermoplastics. Encyclopedia of Materials: Plastics and Polymers, 1, 651-661. https://doi.org/10.1016/B978-0-12-820352-1.00013-4

• Sun, Z., Zhang, L., Liang, D., Xiao, W., & Lin, J. (2017). Mechanical and thermal properties of PLA biocomposites reinforced by coir fibers. International Journal of Polymer Science, 2017(1), 1-8. https://doi.org/10.1155/2017/2178329

• Tahir, K., Nazir, S., Li, B., Khan, A. U., Khan, Z. U. H., Ahmad, A., & Khan, F. U. (2015). An efficient photo catalytic activity of green synthesized silver nanoparticles using Salvadora persica stem extract. Separation and Purification Technology, 150, 316-324. https://doi.org/10.1016/j.seppur.2015.07.012

• Tokoro, R., Vu, D. M., Okubo, K., Tanaka, T., Fujii, T., & Fujiura, T. (2007). How to improve mechanical properties of polylactic acid with bamboo fibers. Journal of Materials Science, 43(2), 775-787. https://doi.org/10.1007/s10853-007-1994-y

• Wang, Y., Liu, S., Wang, Q., Ji, X., Yang, G., Chen, J., & Fatehi, P. (2021). Strong, ductile and biodegradable polylactic acid/lignin-containing cellulose nanofibril composites with improved thermal and barrier properties. Industrial Crops and Products, 171, 113898. https://doi.org/10.1016/j.indcrop.2021.113898

• Xu, J., & Song, J. (2015). Polylactic acid (PLA)-based shape-memory materials for biomedical applications. Shape Memory Polymers for Biomedical Applications, 2015, 197-217. https://doi.org/10.1016/B978-0-85709-698-2.00010-6

• Yee, Y., Ching, Y. C., Rozali, S., Hashim, N. A., & Singh, R. (2016). Preparation and characterization of poly(lactic acid)-based composite reinforced with oil palm empty fruit bunch fiber and nanosilica. BioResources, 11(1), 2269-2286. https://doi.org/10.15376/biores.11.1.2269-2286

• Yu, T., Ren, J., Li, S., Yuan, H., & Li, Y. (2010). Effect of fiber surface-treatments on the properties of poly(lactic acid)/ramie composites. Composites Part A: Applied Science and Manufacturing, 41(4), 499-505. https://doi.org/10.1016/j.compositesa.2009.12.006

• Yusoff, R. B., Takagi, H., & Nakagaito, A. N. (2016). Tensile and flexural properties of polylactic acid-based hybrid green composites reinforced by kenaf, bamboo and coir fibers. Industrial Crops and Products, 94, 562-573. https://doi.org/10.1016/j.indcrop.2016.09.017

• Zhang, H., Huang, J., Yang, L., Chen, R., Zou, W., Lin, X., & Qu, J. (2015). Preparation, characterization and properties of PLA/TiO2 nanocomposites based on a novel vane extruder. RSC Advances, 5(6), 4639-4647. https://doi.org/10.1039/c4ra14538k