*2.3. Role of Biocomposites in Industrial Consumption*

In order to conduct further in-depth literature analysis, in total, 1361 articles were selected within the SCOPUS database using keywords "biocomposite" and "biopolymers". The interconnection of keywords was analyzed by VOSviewer, and the visualization of results highlights the main clusters or concepts explored most often in the previous studies. The following picture demonstrates the chronological frequency and interlinkage of the keywords applied in the research (Figure 5).

**Figure 5.** The overlay visualization of co-occurrence of keywords "biocomposite" and "biopolymer" based on the SCOPUS articles, which was created by the authors using VOSviewer (version 1.6.17).

Industrial production based on non-renewable resources, a growing demand for end products, a rapidly growing population, and density are all placing an increasing burden on the resources, and all types of pollution are proliferating at an alarming rate. Consequently, more and more attention is being paid to sustainable economic development by using new natural materials. High hopes are placed on the development of composites reinforced with natural fibers and the versatile use of materials based on non-renewable raw materials [102].

The non-degradable nature of conventional plastic waste in ecosystems has increased consumer interest and scientific research into more environmentally friendly bio-based plastic materials and biocomposites [111]. Due to the advantages of recyclability, lightness, and cost-effectiveness, biocomposites are of interest to researchers in the field [111–114]. Biocomposite constituents such as bio-based polymers and fillers are obtained from renewable natural sources and can serve as a possible replacement for oil-based non-renewable plastics [115]. Biocomposites are reasonably less likely to have an impact on the environment and therefore are considered safer for both human and other living habitats. In addition, most of them are recyclable and reusable. One of the most important benefits of biocomposites is that these materials have a manageable potential at the end of disposal [116]. Biocomposite raw materials are divided into two groups: the first group of raw materials is wood (their use in larger quantities can lead to deforestation and affect biodiversity), while the second group of raw materials is lignocellulosic waste or production by-products collected from food, forest, and agricultural residues. Until now, the second group of by-products has been used for the development of biocomposites, although their commercialization is still limited. Extensive research in the field of biocomposites has led to the development of various types of biocomposites [117].

The role of the reinforcement phase in biocomposite material is to increase the mechanical properties of the polymer matrix system, with different reinforcements having different properties, thus influencing the composite properties in different ways [118]. The need to improve and stimulate rural economies as well as reduce the world's dependency on petroleum-based materials has resulted in much interest and focus on the use of various varieties of natural fibers as reinforcing agents for composite materials [119]. The high strength, availability, low cost, sustainability, and eco-friendly characteristics of natural materials such as agricultural waste make them quite beneficial and efficient as reinforcement for composite materials [120]. Other advantages of natural fibers over synthetic fibers include their acceptable specific properties, ease of separation, and enhanced energy recovery. These advantages of natural fibers (flax, hemp, kenaf, henequen, banana, oil palm, and jute) over synthetic fibers have given lignocellulosic fiber substitutes huge potential for synthetic fibers. In contrast to synthetic fiber-based polymer composites, natural fiberbased composites can be disposed of easily or composted at the end-of-life stage without polluting the environment [121,122].

The commonly used natural feedstocks for biocomposites are flax, hemp, jute, and sisal (see Table 1). There is growing market interest in the use of hemp fiber for a variety of applications due to its quality, availability, and cost. Hemp is a sustainable multi-purpose crop, because it is possible to use all parts of the plant efficiently. Hemp-based materials are reusable, biodegradable, and/or compostable, which helps in achieving the goals of the EU Circular Economy Action Plan and initiatives to stimulate lead markets for climate-neutral and circular products in energy-intensive industrial sectors [10].

Hemp fibers are one of the most environmentally-friendly natural fibers with high tensile strength; they retain their strength in the wet state and other properties that make them suitable for a variety of industrial products. Therefore, hemp is one of the most promising sources of renewable resources to replace non-renewable components in a wide range of industrial products. From the point of view of the concept of sustainable development, the advantage of hemp fiber extraction is that it is possible to use all parts of the plant to produce different products at the same time—hemp seeds, their shells, hemp stalks, thus maximizing their added value. Combining natural fibers in the composite with a matrix derived from natural products succeeds in solving one of the most important problems of the century—preserving the viability of the environment [123].

The European Industrial Hemp Association [124] reported that hemp could allow us to capture and store significant amounts of CO2. One tonne of harvested hemp stem corresponds to 1.6 tonnes of CO2 absorption. Based on land use, using an average yield of 5.5 to 8 t/ha, this is 9 to 13 tonnes of CO2 absorption per hectare harvested. Hemp cultivation requires little or no resources, and it has a positive impact on soil and biodiversity. As all

parts of the plant can be used or further modified, its treatment does not generate waste. Beneficial effects can also be seen in future crops in this soil: studies have shown that wheat yields have increased by 10 to 20% since hemp cultivation [124].

**Table 1.** Property comparison of the commonly used fibers for biocomposites, created by authors based on [122].


New composite materials are constantly being developed in the world, which envisages a wide range of applications. Biodegradable composite material from hemp fiber and polylactide or polymerized corn starch provides the necessary mechanical properties for a wide range of applications, and also the material development technology is suitable for products of various shapes and scales.

Biocomposites are innovative materials consisting of an environmentally friendly polymer matrix and reinforcing fibers and are currently an alternative to traditional composite materials. These materials have a wide range of applications. For biocomposites to be classified as biodegradable and green, they must comply with the principles of Green Chemistry, which is part of the concept of sustainability [125]. To integrate the SDG with biocomposites development and consider them sustainable materials, the acceptance of Green Chemistry principles plays a fundamental role [126,127]. Natural fiber-reinforced PLA biocomposites have potentially valuable properties such as their low density, low cost, and reduced solidity when compared with synthetic biocomposite products [108].

Biocomposites could be classified as bio-based only when both their constituents originate from natural resources. However, it is defined as a green material if the polymer matrix is derived from biomass or petroleum-based sources, and at the same time, the biocomposite is biodegradable [128]. Chemat et al. [128] reported that a relevant example of the petrochemically-derived green biocomposite is poly (ε-caprolactone) (PCL), which is sourced petrochemically, and yet, it is completely biodegradable by aerobic/anaerobic biological processes to carbon dioxide, water, methane, and biomass. It should be noted that the concepts of biological and green should not be confused with "sustainable" biocomposites, which take into account not only one or two aspects, but the whole life cycle of the composite, from cradle to grave [129].

The biocomposite development process could involve the use of biotechnological methods to replace the non-renewable resources, using low-impact manufacturing chemicals and methods, and utilizing waste and recycled content to contribute to circularity. According to this definition, a sustainable biocomposite could be one that contains at least one naturally derived ingredient, and the overall impact of the biocomposite throughout its journey from production to consumption is considered positive without interfering with the environment [129].

Sustainable industrial consumption has been at the core of the Sustainable Development Goals (SDGs). It clearly emphasizes resource efficiency, the minimization and potential use of waste, as well as the minimal use of hazardous substances, also the integration of environmental and social responsibility.
