Evaluation of Mechanical Energy Consumption in WPC Production from Pine (Pinus sylvestris) and Hemp (Cannabis sativa L.) with ABS Thermoplastic Additions

Lignocellulosic Materials and Wood Plastic Composites—Use and Applications

Natural resources such as lignocellulosic materials have been with humanity since the beginning. In the past, it was primarily used as a fuel and a construction material. There has been a significant increase in its use over time. Modern technologies allow the refining and modifying of raw materials to be more widely used. Biodegradable plastics and biocomposites are gaining popularity as alternatives to traditional lignocellulosic materials, which are durable and resistant to biotic and abiotic factors [1]. The furniture industry has used wood-based panels for years, for example, particleboard, plywood, MDF, OSL, PSL, LVL, etc. [2,3]. Each of these types of boards is installed in most rooms, individually or in combination, to create solid connections. Wood particles are combined with resins at the proper pressure and temperature during the curing process to make these boards [4]. These materials are widely used in the furniture industry, where they have displaced all substitutes for a long time.

The pro-ecological policy may create problems with their future use in producing wood-based panels [5]. The European Union, like most countries, constantly tries to protect the environment by setting some restrictions on the acquisition of wood raw materials for the production of wood-based panels [6,7]. Changes in the furniture industry may occur quickly and unexpectedly, and substitutes for classic wood-based panels that are durable, practical, and affordable may be challenging to find. Materials engineering trends are increasingly moving towards green and sustainable solutions that minimize negative environmental impacts. Developing Wood Plastic Composites (WPC) is one of these innovative approaches. These materials combine wood with plastics and are gaining popularity for their mechanical and environmental properties. The advantages of WPCs over traditional building materials include their durability, low susceptibility to biological degradation, and recyclability. Compressive processes in biocomposites and the amount of mechanical energy consumed are important to WPC research. The constituent material moisture content, density, and ash content are essential physicochemical characteristics. Using plastics in the WPC improves its properties by providing durability and resistance to moisture and weathering [8,9]. The prepared research also examines how different factors, including biocomposite composition, influence the compaction process and final product strength.

Currently, there is growing interest in biocomposites combining polymers and lignocellulosic materials. Increasing numbers of companies are producing WPC (Wood Polymer Composites) products as evidence of this [10]. Composites became extremely popular during the 1960s. Innovative materials were developed with unusual properties that were difficult to achieve with traditional raw materials. Composites were expected to meet the demands of designers and constructors [11]. Combining lignocellulosic material and thermoplastics can produce composite materials with even better properties. During the processing, thermoplastics are manufactured, which can be used as a binder [12]. Thermoplastics are characterized by high strength and durability despite their origin from recovery. Thermoplastic polymers like ABS are highly mechanically strong and impact resistant, making them an ideal semi-finished product for hemp fibers.

Furthermore, because of their production process, shives have been widely recognized as waste; however, they are renewable [13,14,15]. These materials can be combined to create highly durable and lightweight products that are not only applicable to the furniture industry but also to other fields, such as automotive or construction. The versatile use of composites in the construction sector is due to their ability to withstand diverse climatic conditions [16].

Approximately six million hectares of land in Poland are planted with Scots pine (Pinus sylvestris), one of the most intensively exploited crops there [1]. Scots pine is ubiquitous in Polish and mixed forests, which explains its high occurrence rate. The potential to regenerate naturally and the economic value of deciduous forest trees create some financial support. The pine species have qualitative and strength properties, which make it a valued species [17]. The tree species determine the wood’s anatomical structure, which is directly related to its density. Among biomaterials, industrial hemp (Cannabis sativa L.) is also becoming increasingly popular [6,18]. In the past, it has spread to many parts of the world, including Poland. Hemp fibers have excellent strength properties and can be easily obtained from large-scale hemp cultivation plants. In Poland and worldwide, hemp is becoming increasingly popular as a potential building and furniture material [19,20]. Despite some legal restrictions, this material is becoming increasingly popular in the domestic market. As an alternative to traditional materials, hemp can also be used commercially, increasing the domestic supply of this raw material. Due to its numerous applications, Hemp is becoming increasingly popular as a lignocellulosic material. These composites are increasingly popular due to their durability and environmental friendliness, which hemp fibers possess.

The most common thermoplastics used to make WPC composites are polyethylene (PE), polypropylene (PP), or polyvinyl chloride (PVC). This study used ABS thermoplastic because of its recyclable properties and widespread availability. The plastic used in producing WPC plays a crucial role in shaping the final product, as it acts as a matrix that binds and stabilizes the lignin-cellulose materials. The thermoplastics used to make these composites are often recycled, which helps reduce plastic waste and promotes sustainability. Recycled plastics, such as PET bottles and industrial waste, can be used to produce WPC, which is both financially and environmentally beneficial. The acrylonitrile-butadiene-styrene copolymer, ABS, certainly deserves attention among the many polymers available. ABS is used in many polymer composites as a structural material and component. The popularity of ABS homopolymer can be attributed to its many favorable properties, such as high thermal and chemical durability, excellent dimensional stability, stiffness, and ease of processing. There is good reason to believe it has widespread use in various industries [21]. As an example of thermoplastics, or thermoplastic elastomers, ABS is one of them. The material can deform plastically under the influence of high temperatures. The material becomes soft during this process, allowing it to be molded and shaped as desired. Thermoplastics become solid, rigid bodies as soon as they cool down, enabling them to maintain their shape with great precision. These plastics have the advantage of being able to be plasticized repeatedly without affecting the material [22].

The wood plastic composites (WPC) are composite materials composed of lignocellulose and plastics. Combining these two components enables the production of materials that combine the attributes of wood and thermoplastics while eliminating many of their disadvantages, such as moisture absorption, deformation, and defects in the wood that affect its strength. Materials used in the manufacturing of WPC are not conventional. It is possible to produce composite materials using wood fibers, sawdust, shavings, and chips [23]. The filler can also be replaced with lignocellulosic materials, such as straw, plant stems, seed co-pops, and bamboo. Composites made of lignocellulosic material and plastic are becoming increasingly popular in various fields due to their unique qualities. WPC’s durability, lightweight, and weather resistance make it ideal for use in the construction industry. This material has many structural uses, including terraces, sidewalks, paths, stairs, floors, house facades, fences, and noise barriers. The aesthetic appearance of WPC makes them an attractive alternative to traditional materials [24]. Furniture manufacturers are increasingly using hemp in furniture production [19,20]. These fibers can be woven into composite boards characterized by light weight, strength, and flexibility. Especially ecological products-based furniture can also be aesthetic and functional.

Biocomposites can be manufactured with a blend of thermoplastics and hemp [25] or pine wood, according to studies published in the literature [26]. Composites based on hemp-ABS, for example, have been evaluated for their mechanical properties [8,27]. Our results show that hemp fibers can enhance ABS’s properties if processed correctly [28]. The durability of composites was also examined by environmental factors, including humidity and temperature [27]. Heat treatment is an effective method for improving the properties of pine wood [29], increasing its dimensional stability and moisture resistance. This research focused on preparing and characterizing a thermoplastic-polymer lignocellulosic biocomposite [23]. This research aims to contribute to the advancement of WPC technology by focusing on the preparation and characterization of a thermoplastic-polymer lignocellulosic biocomposite with varying proportions of pine chips (Pinus sylvestris) and hemp shives (Cannabis sativa L.) bound with an ABS regranulate. The study investigates the impact of ingredient proportions on the strength parameters of the resulting biocomposites. By conducting a thorough strength analysis and detailed statistical examination, this research provides a comprehensive understanding of their properties and application potential, ultimately promoting the development of sustainable and high-performance materials [23,30]. This in-depth analysis of ingredient parameters and proportions is crucial for optimizing composite technologies and materials.

The environmental friendliness of wood-plastic composites makes them more attractive to manufacturers looking for sustainable solutions. In the context of the goal above, evaluating mechanical energy consumption during the compaction process of these wood-plastic biocomposites with ABS thermoplastic is crucial for expanding their application areas and realizing their full potential. This investigation into energy efficiency aligns with the growing demand for sustainable manufacturing practices. WPCs offer inherent advantages due to their lightweight nature and ease of processing, potentially leading to reduced energy consumption compared to traditional materials [31]. The application can reduce weight in various structures, further enhancing energy efficiency. Therefore, this research on mechanical energy consumption in WPC production provides critical insights into the sustainability of this modern material, paving the way for its broader adoption in environmentally conscious industries. The prepared biocomposites will be rigorously analyzed regarding their strength properties and the parameters derived from this process, providing a comprehensive assessment of their performance and potential [31].

2.1. Properties of Applied Materials

Materials are in high demand, requiring new solutions in the industry today [32]. Pine and hemp are considered lignocellulosic materials. The research aimed to prepare an environmentally friendly biocomposite that combines pine or hemp with thermoplastic. The materials used to make biocomposites were chips of pine or shives of hemp and the thermoplastic called acrylonitrile-butadiene-styrene (ABS) terpolymer. Despite being processed, regranulate maintains its properties since it is made from recycled plastics. The study used pine fractions divided into two groups with ranges of 0–1 and 1–4 mm. The binder used for this project was acrylonitrile-butadiene-styrene (ABS) terpolymer combined with shredded pine (Pinus sylvestris L.) wood. The materials were mixed by hand with a spatula. No specialized mixing or grounding equipment was used.

Additionally, the part of the material in mixed fraction form of hemp shives (Cannabis sativa) was also prepared by dividing it into two groups, each having a different fiber length (0–0.4 mm and 0.4–0.8 mm), and mixing them in a ratio of 50 to 50 and 25 to 75 percent with ABS regranulate. The use of regranulate is usually independent of its appearance. Small plastic cubes with a side dimension of 0.3 mm were used in this experiment. Materials characterization includes measurements of two key parameters, including a melt flow rate of 21 g of polymer per 10 min and an impact strength of 13 kJ⋅m⁻². The materials obtained for the research are presented in Figure 1.

Scots pine wood chips are used as a building material because of their mass occurrence and characteristic properties. The versatility and wide range of applications of pine wood have given it a leading position in construction and furniture making. It is important to note that one of the advantages of pine wood is its ease of processing. The timber used has a relatively high degree of compressive strength, which creates a wide range of construction possibilities. A significant variation in density and strength characterizes the anisotropic structure of the material. The material has a considerable variation in thickness and strength because of its anisotropic structure. A limitation of using pine wood is its defects, such as knots, blue stains, and bark pockets. In the industrial aspect, an additional undesirable feature is hygroscopicity, manifested by a tendency to absorb moisture or give it away to the environment until it reaches a state of equilibrium between its moisture content and that of the environment [32].

Hemp is composed of fibers and the woody part of the stem created during the processing of hemp straw into fibers, called shives. Composite materials from hemp shives can be manufactured in various forms [10]. Shives, previously considered waste materials resulting from the processing of hemp straw, are now regarded as valuable commodities [11]. The hemp stalk comprises a wooden core and a fiber arranged along its stem that surrounds the wooden core. Shives are used to describe the pieces that are cut from the stem. The stem of the plant has a space in the middle. The use of hemp shives in combination with thermoplastic allows the creation of an eco-friendly thermoplastic with sought-after material properties.

Fractions of lignocellulosic material were combined with a thermoplastic polymer to create the composite material. The ability and capacity of thermoplastic to repeatedly convert from a solid state to a rubber-like state under heat is its most sought-after processing characteristic. The change in temperature affects the plasticity of the material used. Temperatures between 190 °C and 230 °C were considered most appropriate for this process. The acrylonitrile-butadiene-styrene terpolymer ABS can be produced by polymerizing 1,3-butadiene and copolymerizing acrylonitrile with styrene, followed by grafting the polybutadiene copolymer onto the acrylonitrile copolymer [12]. The combination of thermoplastic and lignocellulosic materials results in a material with valuable physical properties. In addition to improving the material’s moisture resistance, ABS increases its resistance to wood decomposition and facilitates processing. The strength and flexibility of the semi-finished product make it a good fit for applications that require strength and flexibility. Combining hemp and ABS thermoplastic can create a sustainable solution that meets both technical and ecological requirements and reduces the consumption of natural resources. Reducing non-renewable resources improves the mechanical properties and sustainability of the material. The sought-after mechanical properties are leading to the commercialization of WPC composites.

2.2. Samples Preparation

2.3. Hot Water Extraction (HWE)

Hot Water Extraction (HWE) was used to extract lignocellulosic material fractionated for the study. It has been determined that 10 g of the material has been weighed and placed in a container for testing the material before each process is initiated. The extraction was performed in a unique cylindrical device, using 400 g of distilled water under strictly controlled temperature (105 °C) and pressure (2 MPa). During the test of a single process, it took approximately 30 min for it to complete. The material and distilled water were replaced after the first extraction, and the process was repeated. After another exchange, three more repetitions of HWE were carried out on the following material. The hot water extraction set is shown in Figure 5.

According to the figure, the reactor lid is integrated into the solution container after extraction. Number 2 denotes the container for the chips, which undergo the HWE process. The reactor body was marked with the number 3. During the process, the container was refilled each time with distilled water, which, as a medium, flowed through the material during the process. Heat was being provided to the set at the bottom of the unit. High temperatures and pressures caused water to pass through the material, extracting the solution, which flowed into container 1. He was transferred to specially marked containers to dry the extracted material, which was then placed in a dryer. The post-extraction distilled water collected in the container was poured into labeled and weighed flasks. To obtain the weight of the sediment, an evaporation process was carried out on the flask containing the overflowing distilled water. The residue remaining after evaporation was brewed in a flask. The mass of the empty flask, weighed before extraction began, was subtracted from the result, obtaining the mass of the residue. In the same way as the native material, the post-extraction material was concentrated with ABS included. The intensity of the extraction process was controlled by repeated cycles of Hot Water Extraction (HWE) on the prepared raw material. The initial cycle of HWE I was conducted after filling the container with wood chips. After exchanging the analyzed material and distilled water, the HWE II process was repeated twice by adding only 400 mL of distilled water. Following the second cycle, the material and water were again replaced, and three more cycles of HWE III were conducted according to the methodology, supplementing the water by 400 mL for each time of change. This procedure allowed for a gradual increase in the extraction intensity, which allowed for more material recovery from the plant material with a higher degree of accuracy.

2.4. Structure and Function of the Compaction Head

The compaction set made from steel was designed to simulate the conditions compressing lignocellulosic material during actual compaction processes. The piston and chamber diameter were carefully selected to ensure that the unit pressure exerted on the material reached 3.5 MPa [36], a value known to be sufficient for binding the comminuted material together. The testing machine could generate a force of 100 kN, which provided the necessary compressive force to achieve this pressure unit. The integrated heating module played a vital role in the compaction process. By controlling the temperature of the material, it was possible to study the effects of heat on the compaction properties of lignocellulosic materials. The control panel could control the temperature precisely, ensuring the desired conditions were met throughout the testing process. The overall design of the test stand was carefully considered to ensure that the compaction process could be accurately monitored and controlled. The specialized equipment, including the compaction head, heating module, and control panel, provided the necessary tools for conducting comprehensive research into the compaction of lignocellulosic materials. The compaction set is illustrated in Figure 6.

Three structural elements form the prototype compaction head. The main one is a cylindrical sleeve in Figure 6, no. 2, mounted on a steel bracket in Figure 6, no. 3, and connecting the system to the testing machine via a steel shaft. The sleeve houses the movable component of the system, namely the compression head in Figure 6, no. 1. The compression heads are designed to achieve a certain unit pressure. The value of the maximum force generated by the compression machine (F_max) and the size of the inner diameter of the compaction chamber had to be adjusted to achieve this value. Calculations were carried out to determine that the chamber’s inner diameter was equal to 11 mm. A cylinder with a height of 100 mm was included in the compaction set. The compaction of lignocellulosic materials at elevated temperatures is negatively affected by thermosensitizing factors. Compaction generates heat internally under stable conditions as well. The laboratory head is essential for maintaining the desired temperature in laboratories. A compaction head with an external heating unit was used to achieve laboratory conditions. Band heaters (GOGO-04349) (Warsaw, Poland) were used here. As a result, it was possible to determine the temperature to within one °C during the test. It ranged from 0 to 800 °C. The band radiator used here was 25 mm high. It was controlled by a thermocouple inside the heater through the 280-watt ESM-3710 controller. Digital readings of the controller gave an accuracy of 1%.

2.5. The Raw Material Compaction Process

The laboratory process of preparing biocomposite materials requires precision and care. Shaking machines are used to separate hemp shives into fractions based on carefully selected screens. The next step is to thoroughly mix the two materials in appropriate proportions, which ensures even distribution of the components and, ultimately, the homogeneity of the composite. The thermoplastic ABS is heated to the appropriate plasticity in the next phase, facilitating the forming process. To ensure uniformity and density of the composite, the laboratory material is compacted in a testing machine using a specially designed compaction sleeve. Compression is followed by the sleeve’s tempering and cooling, stabilizing the material’s structure and properties. Technically advanced and precise, this process produces biocomposite properties that match expectations. Plasticized granulates play an important bonding role by replacing traditional adhesives, affecting the final product’s strength and durability. The present study implemented a model of a compaction head and connected it to a stress-testing machine. Compaction processes were carried out in the laboratory using a compaction head. Material parameters such as moisture content, granulometric composition, and process temperature had to be considered during the process. The compaction head was heated first in the test to ensure consistent temperature conditions throughout the experiment. The heating step was essential to simulate natural conditions accurately and achieve reliable results. The specially prepared compacting head is presented in Figure 7.

The research carried out was combined with the implementation of a model of a compaction head that cooperated with a stress testing machine. Controlled compaction processes in the laboratory were carried out with the help of the compaction above head. The process had several stages. The parameters of the material (moisture level and granulometric composition) and the method (temperature) were considered. The first stage introduced crushed material of a specific fraction and a specific percentage of ABS into the thickening sleeves. In the second phase, the compaction head and material were heated to a particular temperature in a dryer. In the third stage of the compaction process, the piston of the compaction head was locked in the upper part of the testing machine. The raw material was gradually compacted under pressure. After compaction, the piston was moved back to its starting position to remove the finished product. The product was removed using a compression head piston or an additional tool due to the product itself. The test rig explicitly designed for the study enabled measurements and control of the compaction parameters. The tests were carried out using a compaction head, the parameters of which did not differ significantly from those found in professional machines. Based on this, it can be concluded that the compaction head performs well in typical conditions where lignocellulosic materials are compacted. The final product had a diameter of about 14 mm.

2.6. Measuring the Ash Content

Inorganic components and purity of the material can be determined by the ash content, which is the residue after burning the material at high temperatures. The ash content of raw material is essential in determining its chemical composition. Identifying the ash content is a crucial component of quality control since it allows us to select materials that will produce composites with the desired properties. Determination of the ash content of the material involves ashing the sample at a high temperature and then accurately weighing the residue. This process is carried out in STOL’s muffle furnace, where the sample is subjected to a temperature of 800 °C. The material is wholly burned at this temperature, and the residue represents ash, which is then weighed on a precision analytical balance. The weighted ash represents the ash content of the sample being analyzed, which allows the amount of material to be determined relative to the weight of the entire sample. This method is a standard procedure used in chemical and physical analyses, po-posing to accurately determine the ash content of the material under study. Each sample was processed in a muffled oven for six hours. After charring, the samples were removed from the device, cooled, and accurately weighed. After washing, the samples were cooled in a desiccator, and the weight of the crucible, including the ash, was determined. A crucial part of this process is determining the ash content of the raw material, which is essential in assessing the material’s quantitative chemical composition. The remaining mass is converted to a percentage based on the results of the analysis. During the combustion test of the material, factors such as the duration of the process and temperature are essential. The listed parameters must be controlled to ensure uniform and reproducible incineration conditions. Despite similar chemical compositions, different material fractions may exhibit differences in material properties due to differences in consistency or density, which can also affect the combustion process and the final composition of the ash [37,38].

2.7. Statistical Analysis

The research was conducted to understand how the research materials were processed, which resulted in collecting a large amount of relevant data regarding the process by which the materials were processed. ANOVA (analysis of variance) has been used to characterize the correlation between the results obtained to support the primary statistical analysis. Analysis of variance (ANOVA) is a parametric statistical method for comparing more than two groups of data, separated based on one or more variables (univariate or multivariate). The primary purpose of variation analysis is to compare the dispersion (variance) of the dependent variable between groups that have been separated according to the independent variables. Scientists commonly compare averages between groups to determine the significance of differences [39,40].

During statistical analyses, the concept of variance is a fundamental measure of the variability of observed results. It can be interpreted as the arithmetic mean of the squares of the deviations of specific trait values versus the collective arithmetic mean [23,24]. It is worth noting that the value of the variance is always non-negative. The greater the value of the variance, the greater the variation that can be observed in the collective in the context of a given trait [39]. The study evaluated the effects of physical parameters on lignocellulosic biocomposites and thermoplastic ABS. As part of the method, Duncan’s test was used to divide the measured parameters into homogeneous groups [36]. The statistical analysis assumed that the other factors would remain constant. To obtain reliable conclusions from the experiment, excluding the influence of different variables is essential.

3.1. Material Granulometric Properties

The granulometric properties of pine material play a key role in its use. The different fractions of lignocellulosic material can have different durability and processability, so defining the relevant fractions in the research process was essential. The first group of pine fractions used in the laboratory study was characterized by particle sizes falling within the range (0 ÷ 1 mm), while the second group included particles of size (1 ÷ 4 mm). An additional post-split group was introduced in the mass of hemp shives, where it was divided into groups of (0 ÷ 0.4 mm) and (0 ÷ 0.8 mm). Within the framework of the laboratory tests carried out, varied fractions of lignocellulosic material were used along with a binder in the form of ABS plastic with fractions ranging from 0 to 4 mm. ABS plastic is a thermoplastic material characterized by good mechanical strength, hardness, and chemical resistance. In addition, ABS is characterized by ease of molding, which is essential for processing this material. The samples were thoroughly mixed by hand before measurement to ensure homogeneity.

Several factors contributed to the segmentation of hemp shives into fraction groups, such as their mechanical properties and their influence on the parameters of the final biocomposite [34]. Smaller particles in the fraction can lead to a more homogeneous composite structure, while larger particles can add favorable mechanical properties, such as structural strength [36]. These two fractions made studying particle size effects on biocomposites possible. Particle size diversity will likely significantly affect biocomposite mechanical properties and stability. As a result of fractionation, the process of compaction of the raw material can be controlled more effectively, leading to improved consistency and homogeneity in the resulting biocomposites. The approach also allows for optimizing composite properties for specific applications, ensuring tailored performance characteristics. Advanced biocomposites with enhanced functionality and environmental benefits can be developed based on these findings. Research conducted on prepared material based on biocomposite production included an analysis of its moisture content as one critical step. According to current standards [33], precise measurements revealed that the tested material had a lower moisture content. It was necessary to increase the moisture content of the raw material to 12% after this value proved suboptimal. This procedure was carried out in laboratory cuvettes explicitly designed for this purpose, allowing precise humidity control. Increasing the moisture content of raw material enabled further processing, which improved the mechanical and dimensional properties of the biocomposites. Controlling moisture at this stage is extremely important, especially with compaction processes requiring adequate moisture to produce optimal results [41,42]. Adding 12% moisture to the shavings enhances the bond between the hemp fibers and the polymer matrix, increasing the final product’s strength. To determine how this factor influences the mechanical properties of biocomposites, we will divide the sample into fractions of different sizes. The physical parameters and moisture content of raw materials can be altered to improve the quality and properties of a biocomposite. To improve biocomposites’ mechanical and physical properties, further research will focus on the characterization and analysis of compaction processes.

The part of natural raw lignocellulosic materials is characterized by low weight and high mechanical strength. The hemp plant is an extremely promising intermediate for making innovative composite materials from renewable raw materials. The unique mechanical properties of these materials enable them to find applications in various fields. It is possible to create biocomposites from hemp by using a densification method that fully utilizes its beneficial properties. Hamp have a wide range of potential applications due to their unique properties. To increase the properties of the pine fraction, which lacks such high properties compared to hemp fibers, it was interesting to modify the material by using the HWE method before biocomposite production. The amount of ABS in the final product also adversely affected hemp biocomposites. According to the planned research, two mixtures were prepared, differing in the composition of material fractions. The first mixture was prepared with 50% ABS and 50% pine for fractions 0 ÷ 1 mm, interfering with fractions using the HWE method. The second mixture contained 50% ABS and 50% pine material 1 ÷ 4 mm, where the HWE method was also used for different cycles. These mixtures were subjected to a compaction process to achieve optimal density. In addition, hemp fractions of 0 ÷ 0.4 and 0.4 ÷ 0.8 mm were subjected to a compaction process in addition to 25 and 50% ABS. The goal was to analyze the effects of the combination of particle size on the compaction process of bio-composites. This method made it possible to thoroughly study the behavior of each fraction during the compaction process

3.2. The Specific Density Analysis

The research on the specific density of biomass focused on analyzing the material’s ability to compact by considering the material’s internal porosity. Biomass density was assumed to be based on the capacity of the material to compact during uniaxial compression to reduce or eliminate intercellular gaps. The filling of intercellular gaps defines the specific density of the raw material. Laboratory studies are essential in producing biocomposites and creating vegetation-based materials, which contribute to the more efficient use of the compaction process. During the experiment, biomass samples were immersed in distilled water as a medium, and the meniscus reading was the specific volume level of a given raw material. The quotient of the mass of the measured raw material by the volume, considering the external pores, corresponded to the specific density. The tests included samples of selected fractions for pine and hemp species. The particular density analysis of the compaction material involved a mathematical simulation of the packing of the material in the form of a biocomposite during compression. The packing factor, which is the product of the bulk density of the material, was used to evaluate the effectiveness of compaction Ψ [34,36]. This factor reflects the material’s ability to fill the available space under pressure. Multiple measurements of the volume of lignocellulosic material using a helium pycnometer allowed its packing factor to be determined at 0.62. This level’s specific density conversion factor was set for lignocellulosic materials with a fraction range of 0 ÷ 8 mm [34]. The device’s precision enabled accurate volume measurements, considering even the smallest pores in the plant material. The results provided valuable information about its structure and properties, which allowed for optimal adjustment of the packing factor to the specifics of the process. A high packing factor indicates the material tendency to arrange itself densely, which is beneficial in many applications, such as the production of biocomposites.

3.3. The Process of Compaction of Pine with the Addition of ABS

3.4. Compression Process with Energy Characteristics