Mechanical properties of LDPE and PS polymer matrix composites reinforced with GNP and CF — A critical review

There is always a vital need for more robust, affordable, and multifunctional materials to satisfy the demands of industrial consumers. Therefore, polymer matrix composites (dual and hybrid matrix) have become popular with multiple fillers to meet these needs. Graphene nano-platelet (GNP) and Carbon fibre (CF) are popular among those fillers due to their superior properties, such as good mechanical, thermal, and electrical properties. Low density polyethylene (LDPE), Polystyrene (PS), GNP, and CF are popular and heavily used in the packaging, automotive, and aerospace industries. However, it would be good to look at how these areas have evolved over the last few decades. Hence, this review focuses on a comparison of LDPE and PS as a matrix and GNP and CF as a filler, considering the content that determines the overall performance of blends and composites. The literature was screened for the last few decades. The blends and/or composites produced by a twin-screw extruder were included. A total of 1628 relevant papers were retrieved from all databases. Based on the review, it was deduced that more research should be needed in areas such as the aerospace industry to identify optimum content. Most of the analysis showed that factors such as filler surface area, dispersion, and content affect overall blends and composites' performance in terms of mechanical properties, especially elastic modulus and tensile strength, and other properties. Based on the review, it was realised that using 20 and 30 wt%, 2 and 30 wt%, 2 and 4 wt%, and 20 and 30 wt% filler was the most common combination giving the optimum content for LDPE, PS, GNP, and CF, respectively. EMS and TSH changes of the composites were calculated according to their optimum content. Overall, LDPE and PS are good in packaging areas, but their mechanical properties still need to be improved for use in industries such as automotive, aerospace etc. Due to the advantages of GNP and CF, they are used in different applications, such as electrical devices, medical tools, and automobile vehicles. However, these properties are affected easily by interfacial adhesion, dispersion, and aggregation. Many researchers have searched these parameters and analysed how to prevent the negative effects of these parameters. In conclusion, this review will be helpful for researchers and industrial people to be aware of the state-of-the-art of carbon-based composites and the evolution of LDPE, PS, GNP, and CF.