Composite material comprising padauk wood particles

Abstract

The invention relates to a biodegradable composite material comprising a biodegradable polymer matrix and Padauk wood particles dispersed in said polymer matrix.

Description

Composite material containing Padouk wood particles FIELD OF INVENTION

[0001] The technical field of the present invention relates to biodegradable composite materials. More particularly, the invention relates to composite materials comprising a biodegradable polymer matrix and lignocellulosic fillers such as Padauk wood particles. STATE OF THE ART

[0002] Modern industry faces increasing environmental challenges, particularly the need to reduce the use of petroleum-based materials and limit the production of non-biodegradable waste. In this context, the development of environmentally friendly and biodegradable materials has become a priority for many industrial sectors, as well as to meet consumer demands.

[0003] Biodegradable polymer matrices have emerged as a promising alternative to conventional plastics. These matrices, derived from renewable and bio-based resources, offer the advantage of being compostable under industrial conditions. However, despite their environmental benefits, biodegradable polymer matrices suffer from certain technical limitations, notably low thermal resistance and relative fragility, which restrict their applications. Current research aims to improve these properties while preserving the inherent ecological advantages of this material.

[0004] At the same time, the use of lignocellulosic materials in the composition of industrial products is generating increasing interest. Among these materials, Padauk wood stands out for its remarkable mechanical properties and natural durability. This exotic wood, characterized by its high density and inherent resistance to fungal attacks and wood-boring insects, offers promising prospects for various industrial applications. However, its use remains limited to cabinetmaking and instrument making, due to its relative scarcity and the difficulty of integrating it into large-scale production processes.

[0005] There is therefore a need for new composite materials that combine the advantages of biodegradable polymer matrices in terms of biodegradability with the mechanical and aesthetic properties of exotic woods, while preserving compatibility between components and maintaining overall biodegradability of the material.

[0006] The proposed invention aims to meet this need by offering a new composite material that synergistically combines the properties of biodegradable polymer matrices and Padouk wood.

[0007] The invention therefore relates to a biodegradable composite material comprising a biodegradable polymer matrix and Padouk wood particles dispersed in said polymer matrix.

[0008] Combining Padauk wood particles with a biodegradable polymer matrix improves the material's mechanical properties, such as tensile strength, rigidity, and impact resistance. Furthermore, the synergy between the biodegradable polymer matrix and the Padauk wood particles results in a material that is stronger than if it were composed solely of the biodegradable polymer matrix.

[0009] Padouk gives the composite material according to the invention a natural resistance to fungal and microbial attacks, which increases its durability.

[0010] Similarly, Padouk improves the thermal stability of the composite material, increasing its resistance to deformation under the effect of heat.

[0011] Finally, Padouk gives the composite material according to the invention a natural colouring without the addition of synthetic pigments.

[0012] According to one embodiment of the invention, the Padouk wood particles represent between 10% and 30% by mass of the total mass of the composite material.

[0013] The inventor discovered that a composite material according to the invention, comprising between 10% and 30% by mass of Padauk wood particles, exhibited optimal thermal and mechanical resistance. Furthermore, compared to a material comprising only a biodegradable polymer matrix, it offers the following advantages: an increase in Young's modulus of 10% to 40%, an increase in tensile strength at break of 5% to 20%, an increase in unnotched Charpy impact resistance of 10% to 30%, a decrease in density of 2% to 8%, an increase in the deformation temperature under load of 5°C to 15°C, improved creep resistance at elevated temperatures, improved gas and moisture barrier properties of 5% to 15%, a decrease in mold shrinkage of 10% to 25%, and improved UV resistance.

[0014] According to another embodiment of the invention, the Padouk wood particles have a particle size between 10 µm and 1000 µm.

[0015] The particle size of the Padauk wood allows for a homogeneous distribution of particles within the composite material. Furthermore, this helps to even out mechanical stresses within the composite material.

[0016] Similarly, the size of the Padouk wood particles allows for an optimal contact surface between the polymer matrix and the Padouk wood particles in order to improve interfacial adhesion and thus strengthen the mechanical properties of the composite material.

[0017] Therefore, a good distribution of Padauk wood particles within the composite material reduces gas and moisture permeability. Larger Padauk wood particles tend to create a more convoluted path within the composite material, facilitating the diffusion of molecules.

[0018] According to yet another embodiment of the invention, the polymer matrix comprises one or more compounds selected from the group consisting of polylactide acid, polyhydroxyalkanoate, poly(butyl succinate), polybutylene adipate terephthalate, polycaprolactone, thermoplastic starch and regenerated cellulose.

[0019] This diversity of biodegradable polymers allows for control over the technical characteristics of the composite material, such as biodegradability, mechanical properties, and thermal resistance. By combining polymers to form a matrix, it is possible to obtain a composite that meets specific requirements in terms of performance and environmental sustainability, while ensuring compatibility with Padauk wood particles.

[0020] This allows the fields of application of the composite material to be extended, ranging from biodegradable packaging to ecological technical parts, while offering the possibility of adapting the material to the specific constraints of different industrial sectors.

[0021] According to yet another embodiment of the invention, the composite material has a density between 1.20 and 1.32.

[0022] This density range gives the composite material the desired mechanical strength. Advantageously, the density is determined according to the ISO 1138 method.

[0023] According to yet another embodiment of the invention, the composite material has a hot melt index of between 105 grams per 10 minutes and 117 grams per 10 minutes.

[0024] This range of hot melt flow indices allows for easy shaping of the composite material using techniques such as injection molding or extrusion, while ensuring good filling of complex molds and high productivity in industrial manufacturing processes. Advantageously, the hot melt flow index is determined according to ISO 1133 at a temperature of 190 °C and with an applied load of 2.16 kg.

[0025] According to yet another embodiment of the invention, the composite material has a Vicat softening temperature between 57 °C and 66 °C.

[0026] This Vicat softening temperature range allows the structural integrity of the composite material to be maintained under normal operating conditions while remaining easily processable at relatively low temperatures. Furthermore, it increases energy consumption during the shaping of the composite material. Advantageously, the Vicat softening temperature is determined according to the ISO 306 method.

[0027] According to yet another embodiment of the invention, the composite material has: a tensile strength at break of between 45 MPa and 55 MPa, an elongation at break of between 2% and 3.2%, and a Young's modulus of between 4000 MPa and 5000 MPa.

[0028] Advantageously, the tensile stress at break, the tensile elongation at break and the Young's modulus are determined according to the ISO 527 method.

[0029] These specific mechanical properties give the composite material a balance between rigidity, strength and ductility, making it particularly suitable for lightweight structural applications requiring good mechanical strength without excessive deformation.

[0030] According to yet another embodiment of the invention, the composite material exhibits an unnotched Charpy impact resistance of between 6.4 kJ / m 2 and 8 kJ / m 2 .

[0031] This range of unnotched Charpy impact resistance offers resistance to impacts and sudden shocks, making it suitable for applications requiring high mechanical durability. Advantageously, the unnotched Charpy impact resistance is determined according to the ISO 179 method.

[0032] According to yet another embodiment of the invention, the biodegradable polymer matrix is ​​represented by polylactide acid, and the composite material comprises 20% by mass of Padouk wood particles.

[0033] This embodiment of the invention makes it possible to obtain a composite material exhibiting a good balance between biodegradability, mechanical properties and aesthetic appearance, while maintaining good implementation and reducing the environmental footprint of the composite material.

[0034] A key advantage of the present invention lies in the reduction of the composite material's environmental footprint. Indeed, the use of a biodegradable polymer matrix, combined with a natural filler such as Padauk wood particles, results in a composite material that is overall more environmentally friendly than traditional composite materials, particularly those based on petroleum-derived polymers.

[0035] Another advantage of the present invention lies in the control of the material's biodegradability. Indeed, the presence of Padauk wood particles allows for modulation of the composite's biodegradation rate, thus providing control over the material's end-of-life.

[0036] Another advantage of the present invention lies in the valorization of natural resources. Indeed, Padouk wood particles constitute a renewable natural resource, and can, for example, be derived from waste or by-products of the wood industry.

[0037] Another advantage of the present invention lies in the reduction of dependence on fossil resources. DETAILED DESCRIPTION

[0038] Other features, advantages and details of the invention will be better understood upon reading the supplementary description that follows.

[0039] In the context of the present invention, "composite material" means a heterogeneous system consisting of at least two distinct phases, combined on a macroscopic scale to form a new material with synergistic properties. Specifically, in the context of the present invention, it is a biodegradable polymer matrix composite reinforced with Padauk wood particles.

[0040] In the context of the present invention, "biodegradable" means the ability of the material according to the invention to undergo significant degradation of its molecular structure under the action of microorganisms naturally present in the environment, such as bacteria, fungi, and algae, leading to its decomposition into simple elements such as water, carbon dioxide, biomass, and organic compounds. This biodegradation must occur under specific conditions of temperature, humidity, and oxygen presence, typically encountered in industrial composting environments or, to a lesser extent, under natural conditions. Thus, the composite material must demonstrate a mass loss of at least 90% within a maximum period of 180 days when subjected to a standardized biodegradability test, for example, as defined in ISO 14855 or ASTM D5338, under industrial composting conditions.Furthermore, degradation residues must not exhibit ecotoxicity and must be assimilable by living soil organisms without adverse effects on the environment.

[0041] In the context of the present invention, the term "polymer matrix" refers to a compound consisting of one or more biodegradable polymers that encapsulates and binds Padauk wood particles. This continuous phase is characterized by its macromolecular structure, composed of long chains of repeating monomers, which gives the composite material basic properties such as cohesion and the ability to transfer mechanical loads.

[0042] In the context of the present invention, "Padouk wood particles" means discontinuous elements, ranging in size from micrometers to millimeters, obtained by mechanical reduction of Padouk wood (Pterocarpus soyauxii), a tropical species characterized by its orange-red color and its specific mechanical and chemical properties.

[0043] In the context of the present invention, "dispersed" means that the Padouk wood particles are spatially arranged and incorporated into the polymer matrix.

[0044] In the context of the present invention, "granulometry" means the size distribution of the Padouk wood particles incorporated into the biodegradable polymer matrix.

[0045] As described previously, the invention relates to a biodegradable composite material comprising a biodegradable polymer matrix and Padouk wood particles dispersed in said polymer matrix.

[0046] The biodegradable composite material according to the invention has a biphasic structure comprising: a continuous phase, or matrix, represented by a biodegradable polymer, and a dispersed phase, or reinforcement, represented by Padouk wood particles.

[0047] Furthermore, the composite material according to the invention synergistically combines the characteristics of the biodegradable polymer matrix and Padauk wood particles. As a result, the composite material synergistically integrates the mechanical, thermal, aesthetic, and functional properties of the polymer matrix and the Padauk wood particles.

[0048] The composite material according to the invention is suitable for shaping by conventional polymer processing techniques such as injection, extrusion and molding.

[0049] The polymer matrix according to the invention is further selected according to the following criteria: its ability to form a continuous phase encompassing the reinforcing particles, its thermoplastic properties allowing shaping by known and easily accessible industrial processes, its biodegradable nature, contributing to the overall degradability of the composite, its chemical and physical compatibility with the Padouk wood particles, and its ability to efficiently transfer mechanical stresses to the reinforcing particles.

[0050] The polymer matrix according to the invention comprises one or more compounds selected from the group consisting of polylactide acid, polyhydroxyalkanoate, poly(butyl succinate), polybutylene adipate terephthalate, polycaprolactone, thermoplastic starch and regenerated cellulose.

[0051] According to one embodiment of the invention, the polymer matrix represents between 70% and 90% by mass of the total mass of the composite material.

[0052] Polylactide acid, or PLA, is particularly preferred for producing the composite material according to the invention.

[0053] PLA according to the invention is a biodegradable and bio-based polymer belonging to the aliphatic polyester family. It is obtained from corn, wheat, and / or potato starch. It has a linear molecular structure, giving the composite material thermoplastic properties, thus allowing it to be shaped by conventional processes such as injection molding, extrusion, or thermoforming.

[0054] PLA has a relatively low glass transition temperature, generally between 55°C and 65°C, which influences its dimensional stability and mechanical properties at elevated temperatures. It also exhibits mechanical strength and stiffness comparable to some petrochemical polymers, thus offering a bio-based alternative for various applications.

[0055] PLA is intrinsically biodegradable, which allows its decomposition under industrial composting conditions and, therefore, the decomposition of the composite material according to the invention.

[0056] PLA also exhibits natural transparency and a capacity for coloring, which allows the composite material according to the invention to be colored by means of reinforcement such as Padouk wood particles.

[0057] PLA also exhibits gas permeability, giving the composite material barrier properties, which are particularly useful for certain packaging applications.

[0058] Padouk wood particles represent the dispersed phase, or reinforcement, of the biodegradable composite material.

[0059] The Padouk wood particles according to the invention have: an average density of 0.70 to 0.90 g / cm³ at 12% moisture, a characteristic bright orange-red color, evolving towards reddish-brown over time, a fine to medium grain with a straight or slightly wavy thread, a Janka hardness of about 1970 N, a modulus of elasticity of about 13.7 GPa, and high resistance to compression and bending.

[0060] Padauk wood particles comprise between 40% and 50% cellulose, between 20% and 30% hemicellulose, and between 20% and 30% lignin. They also contain compounds such as phenolic compounds and terpenes, giving them antioxidant and antimicrobial properties.

[0061] The Padauk wood particles according to the invention also exhibit resistance to fungi and wood-boring insects, which is imparted to the composite material. Similarly, the Padauk wood particles possess natural resistance to UV radiation.

[0062] In addition to its intrinsic properties, Padouk wood is preferred for the production of the composite material because it is a renewable resource and has carbon sequestration potential.

[0063] Padauk wood is easily processed, particularly through particle reduction methods such as grinding and chipping. Furthermore, it is compatible with various surface treatments to potentially improve the interface with the polymer matrix.

[0064] The Padauk wood particles are evenly distributed throughout the polymer matrix, preventing significant localized aggregation or concentration. Each Padauk wood particle is surrounded by the polymer matrix, creating a direct interface between the wood and the polymer. This allows for load transfer and adhesion between the two phases of the composite material.

[0065] Furthermore, the dispersion of Padauk wood particles occurs at the microscopic scale, with interparticle distances ranging from a few micrometers to a few hundred micrometers, depending on the concentration and size of the particles. Although the Padauk wood particles are dispersed within the polymer matrix, they form a distinct phase from the matrix, creating a homogeneous, biphasic system.

[0066] Padouk wood particles can exhibit a random or preferential orientation, influenced by the composite manufacturing process.

[0067] Preferably, Padouk wood particles represent between 10% and 30% by mass of the total mass of the composite material.

[0068] According to one embodiment of the invention, the Padauk wood particles have a particle size ranging from 10 µm to 1000 µm, preferably 500 µm. This allows for precise control over the mechanical properties of the composite material, such as strength, stiffness, and toughness. Similarly, the particle size of the Padauk wood particles influences the rheology of the composite material, particularly its viscosity. Finally, the particle size of the Padauk wood particles allows for control over the aesthetic appearance of the composite material, including its color, surface appearance, and texture.

[0069] Particle size also influences the dispersion and homogeneity of the composite material. The inventor discovered that a particle size of Padouk wood between 10 µm and 1000 µm allows for a balance of mechanical properties and functional characteristics, and facilitates the processing and production of the composite material.

[0070] According to one embodiment of the invention, the composite material has a density between 1.20 and 1.32, preferably 1.26.

[0071] The inventor discovered that this density range offers a good balance between the lightweight nature and mechanical performance of the composite material. Furthermore, it allows for significant weight reduction compared to conventional plastics, while maintaining good structural strength. In addition, this density facilitates the integration of the composite material into existing manufacturing processes and reduces raw material consumption for a given volume. Moreover, this makes the composite particularly suitable for a wide range of applications, from lightweight packaging to technical parts requiring a precise strength-to-weight ratio.

[0072] According to one embodiment of the invention, the composite material has a hot melt flow index between 105 grams per 10 minutes and 117 grams per 10 minutes.

[0073] The inventor discovered that this range of hot flow indices facilitates the shaping of the composite material using common techniques such as injection molding, extrusion, and thermoforming. It ensures efficient mold filling, enabling faithful reproduction of details in molded parts, even for complex geometries. Furthermore, this fluidity promotes faster production cycles, thus increasing productivity. It also contributes to better dispersion of the Padauk wood particles within the polymer matrix, ensuring the homogeneity of the final composite material and, consequently, the consistency of its properties.

[0074] According to one embodiment of the invention, the composite material has a Vicat softening temperature between 57 °C and 66 °C.

[0075] The inventor observed that this Vicat softening temperature range gives the composite material improved thermal stability. Furthermore, it increases resistance to deformation under load at moderate temperatures, thus expanding the potential applications of the composite material. Similarly, it enhances the composite material's durability under varying temperature conditions, providing a safety margin for specific applications. In addition, it allows for post-molding operations at moderate temperatures, increasing the versatility of the composite material in complex manufacturing processes.

[0076] According to one embodiment of the invention, the composite material has: a tensile strength at break of between 45 MPa and 55 MPa, an elongation at break of between 2% and 3.2%, and a Young's modulus of between 4000 MPa and 5000 MPa.

[0077] The inventor observed that these properties give the composite material a balance between strength, ductility, and stiffness. The tensile strength at break ensures good resistance to loads, while the elongation at break allows for some deformation before fracture, thus preventing excessive brittleness. The Young's modulus gives the material optimal stiffness. Furthermore, this allows the composite material to be adapted to a variety of structural and non-structural uses, while offering superior performance compared to polymer matrices alone, thanks to the incorporation of Padauk. In addition, this enables the material to meet the requirements of a wide range of industrial applications.

[0078] According to one embodiment of the invention, the composite material exhibits an unnotched Charpy impact resistance of between 6.4 and 8 kJ / m².

[0079] The inventor discovered that this range of unnotched Charpy impact resistance gives the composite material enhanced resilience. Furthermore, it offers excellent resistance to impacts and shocks, thus increasing the durability of the composite material under dynamic operating conditions. Similarly, it significantly reduces the risk of brittle fracture under impact, enhancing safety in various applications of the composite material.

[0080] Therefore, the composite material is particularly well-suited to applications requiring high impact resistance, while maintaining a good balance with other mechanical properties such as rigidity. This resilience contributes to the versatility of the composite material, making it suitable for meeting the requirements of a wide range of industrial and consumer applications.

[0081] The following description relates to examples of composite materials according to the invention Example 1: PLA-Padouk 10% Composite

[0082] Padauk content: 10% by mass. Particle size: 10-100 µm. Density: 1.21 g / cm³. Melt flow rate: 115 g / 10 min. Vicat softening temperature: 58.5 °C. Tensile strength at break: 54 MPa. Elongation at break: 3%. Unnotched Charpy impact strength: 6.6 kJ / m 2 Young's modulus: 4100 MPa.

[0083] This composite is used, for example, to create filaments for 3D printing. Example 2: PLA-Padouk 15% Composite

[0084] Padauk content: 15% by mass. Particle size: 50-200 µm. Density: 1.23 g / cm³. Melt flow rate: 113 g / 10 min. Vicat softening temperature: 59.8 °C. Tensile strength at break: 48.5 MPa. Elongation at break: 2.8%. Unnotched Charpy impact strength: 6.9 kJ / m 2Young's modulus: 4250 MPa.

[0085] This composite is used, for example, for biodegradable rigid food packaging. Example 3: PLA-Padouk 20% Composite

[0086] Padauk content: 20% by mass. Particle size: 100-500 µm. Density: 1.26 g / cm³. Melt flow rate: 111 g / 10 min. Vicat softening temperature: 61.4 °C. Tensile strength at break: 49.7 MPa. Elongation at break: 2.6%. Unnotched Charpy impact strength: 7.19 kJ / m 2 Young's modulus: 4450 MPa.

[0087] This composite is used, for example, for non-structural interior automotive parts. Example 4: PLA-Padouk 25% Composite

[0088] Padauk content: 25% by mass. Particle size: 200-800 µm. Density: 1.28 g / cm³. Melt flow rate: 108 g / 10 min. Vicat softening temperature: 63.2 °C. Tensile strength at break: 51.2 MPa. Elongation at break: 2.4%. Unnotched Charpy impact strength: 7.5 kJ / m 2 Young's modulus: 4650 MPa.

[0089] This composite is used, for example, for durable outdoor furniture. Example 5: PLA-Padouk 30% Composite

[0090] Padauk content: 30% by mass. Particle size: 400-1000 µm. Density: 1.31 g / cm³. Melt flow rate: 106 g / 10 min. Vicat softening temperature: 65.0 °C. Tensile strength at break: 53.0 MPa. Elongation at break: 2.2%. Unnotched Charpy impact strength: 7.8 kJ / m 2 Young's modulus: 4900 MPa.

[0091] This composite is used, for example, for decorative panels in the building industry.

[0092] Furthermore, the composite material according to the invention can be used in the following areas: Industrial packaging such as rigid boxes, trays, and reusable containers. 3D printing. The automotive industry, particularly for the manufacture of high-end interior parts, such as door panels, center consoles, and decorative elements. Consumer goods, such as protective phone cases, eyeglasses, high-end kitchen utensils, and fashion accessories. The construction sector, such as decorative panels, wall coverings, and furniture components. The furniture sector, such as for the manufacture of eco-friendly furniture combining the appearance of Padauk wood with the ease of molding biodegradable polymer matrices. Equipment, such as rackets, gardening tool handles, or bicycle components.The textile industry, for example, for clothing, carpets, and other technical textiles. The medical sector, for example, for the manufacture of biodegradable implants, sutures, drug delivery devices, and other temporary medical applications. Agriculture, for example, for the manufacture of biodegradable mulch films and flower pots, which decompose naturally in the soil, thus reducing plastic waste in agriculture.

Claims

Biodegradable composite material comprising a biodegradable polymer matrix and Padouk wood particles dispersed in said polymer matrix. Composite material according to the preceding claim, characterized in that the Padouk wood particles represent between 10% and 30% by mass of the total mass of the composite material. Composite material according to claim 1 or 2, characterized in that the Padouk wood particles have a particle size between 10 µm and 1000 µm. Composite material according to any one of the preceding claims, characterized in that the polymer matrix comprises one or more compounds selected from the group consisting of polylactide acid, polyhydroxyalkanoate, poly(butyl succinate), polybutylene adipate terephthalate, polycaprolactone, thermoplastic starch and regenerated cellulose. Composite material according to any one of the preceding claims, characterized in that it has a density between 1.20 and 1.

32. Composite material according to any one of the preceding claims, characterized in that it has a hot melt index between 105 grams per 10 minutes and 117 grams per 10 minutes. Composite material according to any one of the preceding claims, characterized in that it has a Vicat softening temperature between 57 °C and 66 °C. Composite material according to any one of the preceding claims, characterized in that it has: a tensile strength at break of between 45 MPa and 55 MPa, an elongation at break of between 2% and 3.2%, and a Young's modulus of between 4000 MPa and 5000 MPa. A composite material according to any one of the preceding claims, characterized in that it has an unnotched Charpy impact resistance of between 6.4 kJ / m 2 and 8 kJ / m 2 . Composite material according to any one of the preceding claims, characterized in that the biodegradable polymer matrix is ​​represented by polylactide acid, and in that it comprises 20% by mass of Padouk wood particles.