The use of polymer-based composites has been gaining popularity in the industry over the last few decades. Their high strength to weight ratio and high fatigue resistance make these composites the preferred materials for a wide variety of applications. The current trend has inclined towards hybrid fibre reinforced composites owing to their outstanding characteristics compared to non-hybrid composites. Numerous research works have been conducted to study the fatigue life behaviour of such composite materials. This study addressed the monotonic and dynamic performance of non-hybrid and hybrid natural fibre based composite materials, and the factors that influence their fatigue performance, along with the stiffness decay of each composite material. Most studies have shown the superior potential of using natural fibres in place of synthetic fibres in those critical applications that involve tensile and cyclic loading.

Polymers are being used in many applications all around the world. However, there are some drawbacks in the properties of polymers that could hamper their usage in certain applications. Therefore, a new material polymer composite was introduced. A polymer composite is a polymer-based material with the addition of a filler. Many researchers have reported the improvement in the properties of a polymer when a filler was introduced. This helps minimize the disadvantages of using a polymer. As a result, polymer composite products can be used in many industries, such as automobile, aerospace, biomedical, and packaging. Fillers derived from natural minerals, such as dolomite, are among the best reinforcement materials for polymeric materials because they are plentiful and low cost, have high rigidity and hardness, and even have tailorable surface chemistry. The use of dolomite as a filler in a polymer composite system has gained increasing attention in recent years after researchers successfully proved that it is capable of improving the mechanical, physical, and thermal properties of various polymeric materials. However, chemical or physical treatment/modification of raw dolomite is needed in order to prepare it as an efficient reinforcing filler. This procedure helps to improve the performance of the resultant polymer composites. This article reviews the usage of dolomite as a filler in a variety of polymeric materials and how it improved the performance of the polymer composite materials. It also highlights several methods that have been used for the purpose dolomite’s treatment/modification. Furthermore, the role of dolomite as a co-filler or a hybrid filler in a polymer composite system is also discussed, revealing the great potential and prospect of this mineral filler in the field of polymer composites for advanced applications.

The awareness of natural fibers as alternative materials to synthetic fibers in composite applications have increased briskly due to lightweight, non-toxic, low cost and abundantly available. To-date, there are still limited works on fully biodegradable composites also known as biocomposites, especially using long pineapple leaf fiber (PALF) reinforced poly lactic acid biocomposites. Thus, this study presents an investigation of the effects of alkaline treatment and use of different fiber length on the mechanical performance of pineapple leaf fibers reinforced poly lactic acid, biocomposites. Flexural testing was conducted via ASTM D790. The results showed enhancement in flexural properties of the biocomposites when the PALF fibers were treated with alkaline treatment, suggesting an effect of improving mechanical interlocking between matrix and reinforcement due to rougher fiber surface. The flexural strength and modulus of long treated fibers increased from 56.47 MPa and 4.24 GPa to 114.03 MPa and 5.70 GPa respectively compared to long untreated fibers. Â In addition, the effect of fiber length is also proven to affect the overall performance of the biocomposites, in which the long PALF fiber composites exhibit superior flexural properties to those of the short fiber reinforced PLA biocomposites, i.e. flexural modulus of 5.7 GPa and 0.22 GPa for the long fiber composites and short fiber composites respectively. The existence of sodium hydroxide, (NaOH) on PALF fibers were confirmed by FTIR analysis. Surface morphology of both untreated and treated samples was studied by using a scanning electron microscope (SEM). Results from both analyses suggest removal of lignin and hemicellulose on the alkaline-treated PALF fiber reinforced composites led to a rougher fibers surface and formed a better fiber-matrix adhesion, as reflected in the flexural properties of the biocomposites as reported above.