Polylactic acid (PLA) is a thermoplastic polymer produced from lactic acid that has been chiefly utilized in biodegradable material and as a composite matrix material. PLA is a prominent biomaterial that is widely used to replace traditional petrochemical-based polymers in various applications owing environmental concerns. Green composites have gained greater attention as ecological consciousness has grown since they have the potential to be more appealing than conventional petroleum-based composites, which are toxic and nonbiodegradable. PLA-based composites with natural fiber have been extensively utilized in a variety of applications, from packaging to medicine, due to their biodegradable, recyclable, high mechanical strength, low toxicity, good barrier properties, friendly processing, and excellent characteristics. A summary of natural fibers, green composites, and PLA, along with their respective properties, classification, functionality, and different processing methods, are discussed to discover the natural fiber-reinforced PLA composite material development for a wide range of applications. This work also emphasizes the research and properties of PLA-based green composites, PLA blend composites, and PLA hybrid composites over the past few years. PLA’s potential as a strong material in engineering applications areas is addressed. This review also covers issues, challenges, opportunities, and perspectives in developing and characterizing PLA-based green composites.

Thermoplastic starch composites have attracted significant attention due to the rise of environmental pollutions induced by the use of synthetic petroleum-based polymer materials. The degradation of traditional plastics requires an unusually long time, which may lead to high cost and secondary pollution. To solve these difficulties, more petroleum-based plastics should be substituted with sustainable bio-based plastics. Renewable and natural materials that are abundant in nature are potential candidates for a wide range of polymers, which can be used to replace their synthetic counterparts. This paper focuses on some aspects of biopolymers and their classes, providing a description of starch as a main component of biopolymers, composites, and potential applications of thermoplastics starch-based in packaging application. Currently, biopolymer composites blended with other components have exhibited several enhanced qualities. The same behavior is also observed when natural fibre is incorporated with biopolymers. However, it should be noted that the degree of compatibility between starch and other biopolymers extensively varies depending on the specific biopolymer. Although their efficacy is yet to reach the level of their fossil fuel counterparts, biopolymers have made a distinguishing mark, which will continue to inspire the creation of novel substances for many years to come.

Increasing environmental concerns have led to greater attention to the development of biodegradable materials. The aim of this paper is to investigate the effect of banana leaf fibre (BLF) on the thermal and mechanical properties of thermoplastic cassava starch (TPCS). The biocomposites were prepared by incorporating 10 to 50 wt.% BLF into the TPCS matrix. The samples were characterised for their thermal and mechanical properties. The results showed that there were significant increments in the tensile and flexural properties of the materials, with the highest strength and modulus values obtained at 40 wt.% BLF content. Thermogravimetric analysis showed that the addition of BLF had increased the thermal stability of the material, indicated by higher-onset decomposition temperature and ash content. Morphological studies through scanning electron microscopy (SEM) exhibited a homogenous distribution of fibres and matrix with good adhesion, which is crucial in improving the mechanical properties of biocomposites. This was also attributed to the strong interaction of intermolecular hydrogen bonds between TPCS and fibre, proven by the FT-IR test that observed the presence of O–H bonding in the biocomposite.

In this study, thermoplastic cassava starch–palm wax blends, reinforced with the treated Cymbopogan citratus fiber (TPCS/ PW/ CCF) were successfully developed. The TPCS were priorly modified with palm wax to enhance the properties of the matrix. The aim of this study was to investigate the influence of alkali treatments on the TPCS/PW/CCF biocomposite. The fiber was treated with different sodium hydroxide (NaOH) concentrations (3%, 6%, and 9%) prior to the composite preparation via hot pressing. The obtained results revealed improved mechanical characteristics in the treated composites. The composites that underwent consecutive alkali treatments at 6% NaOH prior to the composite preparation had higher mechanical strengths, compared to the untreated fibers. A differential scanning calorimetry (DSC) and a thermogravimetric analysis (TGA) indicated that adding treated fibers into the TPCS matrix improved the thermal stability of the samples. The scanning electron microscopy (SEM) demonstrated an improved fiber–matrix adhesion due to the surface modification. An increment in the glass transition temperature (T_g) of the composites after undergoing NaOH treatment denoted an improved interfacial interaction in the treated samples. The Fourier transform infrared spectroscopy (FTIR) showed the elimination of hemicellulose at wavelength 1717 cm⁻¹, for the composites treated with 6% NaOH. The water absorption, solubility, and thickness swelling revealed a higher water resistance of the composites following the alkali treatment of the fiber. These findings validated that the alkaline treatment of CCF is able to improve the functionality of the Cymbopogan citratus fiber-reinforced composites.