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The growing study of polymer composites has motivated scientists to explore more methodologies to enhance the final demanding properties of polymer composites. Polymer composites have commonly been fabricated using thermosets or thermoplastics with synthetic or natural fillers. Lately, ionic liquids have been applied as coupling agents for polymer composites. In this succinct review, two types of ionic liquids, specifically imidazolium‐ and phosphonium‐based ionic liquids that are applied as coupling agents, are identified. Additionally, the synthesis of ionic liquids with different precursors and reactions is explained. The coupling effect of ionic liquids on the mechanical, thermal, and chemical properties of polymer composites is also succinctly reviewed. The knowledge shown in this review gives a more transparent comprehension of the fabrication of polymer composites coupled with ionic liquids and the essential properties of polymer composites. In conclusion, most imidazolium‐ and phosphonium‐based ionic liquids can improve several mechanical, thermal, and chemical properties of thermoset and thermoplastic composites.

In this research, low-cost thermoplastic such as low-density polyethylene (LDPE) was used as a matrix for preparation of the biocomposites. On the other hand, kenaf core fibre (KCF) has been chosen as natural filler due to its availability and renewability. The hydrophobic (talc) and hydrophilic (calcium carbonate) minerals with different loading (0 to 15 wt%) were utilised as secondary fillers. The biocomposites were prepared via melt mixing technique. The processing, tensile and impact properties of the prepared biocomposites were recorded, measured and compared. From the processing recorder results, it was found that the stabilization torque of the LDPE/KCF biocomposites containing talc is lower than calcium carbonate. For the tensile test results, it can be observed that the tensile strength and tensile modulus of the biocomposites incorporated with talc are greater than calcium carbonate. On top of that, the biocomposites containing talc have low impact strength compared to calcium carbonate. It could be concluded that the LDPE/KCF biocomposites with the incorporation of hydrophobic mineral possessed stiff character, whereas the incorporation of hydrophilic mineral provided tough behaviour to the biocomposites.

Alkaline treatment of the black rice husk ash (BRHA) was done by immersing BRHA in 8 % sodium hydroxide, NaOH, solution for 24 hours and then the treated BRHA (TBRHA) was neutralized, washed and dried in an oven. The TBRHA was subsequently compounded with the polypropylene (PP) by using single screw extruder machine, and followed by compression molding at 185 °C. The physical properties results showed that the density and the water absorption behavior of the TBRHA filled PP biocomposite (TBRHA-PP) are higher and lower, respectively, when compared with the untreated BRHA filled PP biocomposites (UBRHA-PP). The melt flow index value of the TBRHA-PP biocomposite is also higher in comparison with the UBRHA-PP biocomposites. The mechanical properties results exhibited that the tensile stress, tensile strain, flexural modulus and impact strength of the TBRHA-PP biocomposite are higher than of the UBRHA-PP biocomposites. However, the tensile modulus of the TBRHA-PP biocomposite is slightly lower as compared with the UBRHA-PP biocomposites. Therefore, it could be concluded that the alkaline treatment of the BRHA has improved some of the physico-mechanical properties of the BRHA filled PP biocomposites.