Method for producing compostable bioplastics

Abstract

A method for producing a bioplastic from organic feedstock from food and agriculture sources is described, which involves creating a blend of organic feedstock, catalyst(s), starch(es) and plasticizer(s), which is fed through a reactive extruder. The catalyst(s) are metal ions. By controlling the operating conditions of the reactive extruder and the catalysts and amylose content of the starch(es), compostable bioplastics can be created with controlled tensile strength and elasticity without the use of extraction steps that create environmentally harmful waste products.

Description

METHOD FOR PRODUCING COMPOSTABLE BIOPLASTICS FROM FOOD AND AGRICULTURAL WASTEFIELD OF THE INVENTION

[0001] The present invention generally relates to the production of compostable bioplastics with a starch matrix from organic food and agricultural waste.BACKGROUND OF THE INVENTION

[0002] The increasing awareness of plastic pollution, microplastic contamination, and greenhouse gas emissions, particularly those arising from the improper disposal of organic agricultural / food waste, highlights the urgent need for sustainable, innovative materials that address these critical environmental challenges.

[0003] Conventional bioplastic production methods tend to focus on processing plant fibers, such as found in the pulp and paper industries - for example, see US5288318 (Mayer et al.).

[0004] Conventional bioplastic production methods often rely on resource-intensive processes involving separate extraction steps, which typically require large amounts of water and may utilize harmful solvents, such as processes using a xylan extraction. These solvents pose risks to both human health and the environment, undermining the environmental sustainability of such bioplastics.SUMMARY OF THE INVENTION

[0005] This invention is focused on the production of compostable bioplastics from organic food and agricultural waste with a starch matrix through direct in-situ reaction of bioactives. This approach leverages bioactive compounds extracted from organic food waste, particularly agricultural byproducts such as fruit peels, which are combined with starchmatrices to produce compostable materials. Through a direct in-situ polymerization reaction, this method efficiently transforms waste into high-performance bioplastics. The method offers a practical and scalable alternative to conventional petroleum-based plastics, addressing key environmental challenges, including plastic pollution, microplastic contamination, and resource depletion, while promoting circular economy principles and sustainable manufacturing practices.

[0006] The disclosure presents a method for processing fruit peels and waste derived from agricultural activities, as well as byproducts from the juice and smoothie industries. These agricultural and food waste materials, particularly fruit peels, contain valuable bioactive compounds. The waste is preprocessed to improve the extraction of these compounds, ensuring efficient use of raw materials. This step reduces the generation of byproducts that would otherwise be disposed of in landfills, thus supporting waste minimization and resource recovery.

[0007] The method leverages reactive extrusion technology, which is catalyzed by human-safe catalyst(s). The catalyst(s) plays a role in facilitating in-situ polymerization and promoting a cascade of chemical reactions during the extrusion process. The use of this catalyst eliminates or reduces the need for traditional, resource-intensive extraction methods, resulting in lower energy and resource consumption while eliminating the use of water and harmful solvents typically required in extraction. The reactive extrusion process operates efficiently without the addition of water or solvents, enhancing industrial productivity. The mechanical shear forces generated within the extruder not only extract bioactive compounds but also promote chemical bonding with the polymer matrix, resulting in a robust, compostable bioplastic.

[0008] The catalyst accelerates the extraction of bioactive compounds directly from organic waste while using high shear forces generated in a solid-state extruder, which acts as an efficient reactor. These forces ensure improved mixing, interaction, and dispersion of the compounds within a polymer matrix, enabling their effective incorporation into the bioplastic without requiring solvents or melting. On the other hand, the catalyst(s) also stimulate polymerization under intense mechanical action thispromotes bonding between the bioactive compounds and the starch (polymer) matrix, allowing for efficient chemical reactions. This method preserves the bioactivity of the compounds, as the process operates under conditions that avoid thermal degradation. Importantly, the process eliminates the use of organic solvents, thus avoiding traditional solvent-based extraction methods, which often require complex purification steps. No purification of intermediate products is necessary, as extraction and incorporation are completed entirely within the system.

[0009] Once extracted, the bioactive compounds are directly combined in-situ with compostable starch sources, such as corn or potato starch, which serve as the polymer matrix. This seamless in-situ integration eliminates the need for additional extraction steps, simplifying the overall process. The result is a bioplastic with enhanced mechanical properties, including improved strength and flexibility, while maintaining excellent biodegradability. The material meets compostability standards, offering a streamlined, efficient production method for creating a sustainable, environmentally friendly alternative to conventional plastics

[0010] Through this innovative method, pressing environmental challenges are tackled, such as plastic pollution and greenhouse gas emissions associated with organic waste. The disclosure provides a sustainable, scalable solution by:

[0011] Reducing plastic waste: The bioplastic can be entirely compostable, mitigating the accumulation of persistent plastics in the environment and contributing to the reduction of microplastic pollution.

[0012] Converting waste into valuable materials: By utilizing agricultural and food industry byproducts, this process turns waste into high-value, eco-friendly bioplastic, supporting the principles of the circular economy.

[0013] Eliminating or reducing harmful solvents: The solvent-free nature of the process enhances its environmental friendliness, reducing pollution and the use of hazardous chemicals.

[0014] Minimizing or reducing water usage: The process is conducted without the addition of water, further reducing resource consumption and making the method highly efficient from both economic and environmental perspectives.

[0015] In accord with the invention, there is provided a method for the preparation of bioplastics from organic feedstock from food and agriculture sources, comprising the steps of: cleaning the organic feedstock; milling the organic feedstock; blending the organic feedstock with at least one starch matrix, at least one plasticizer, and at least one catalyst to produce a blended organic feedstock; and extruding the blended organic feedstock using an extrusion reactor; where each of the at least one catalyst is selected from the group consisting of metal ions sourced from calcium chloride, iron chloride, magnesium chloride, potassium chloride, sodium chloride, zinc chloride, calcium carbonate, ferrous carbonate, magnesium carbonate, sodium carbonate, zinc carbonate, sodium bicarbonate, potassium bicarbonate, calcium phosphate, calcium sulfate, ferrous sulfate, ferric sulfate, magnesium sulfate, potassium sulfate, zinc sulfate, and zinc acetate; and where the at least one starch matrix, at least one plasticizer, at least one catalyst, the temperature of the extrusion reactor, the pressure at die of the extrusion reactor, the torque of the extrusion reactor, and the rotational rate of the extrusion reactor are chosen based on analysis of the lipids, proteins, fatty acids, hemicellulose, cellulose, and lignin of the organic feedstock and the desired properties of the extruded blended organic feedstock.

[0016] In an aspect of the invention, the combined weight percentage of cellulose plus hemicellulose plus lignin in the organic feedstock is less than 30%.

[0017] In another aspect of the invention, in the blended organic feedstock: the weight of organic feedstock to the sum of the weights of the organic feedstock and the at least one starch matrix is between 5% and 75%; the weight of the at least one catalyst to the total weight of the blended organic feedstock is 20% or lower; and the weight of the at least one plasticizer to the total weight of the blended organic feedstock is 40% or lower. In still another aspect of the invention, in the blended organic feedstock: the weight of organic feedstock to the sum of the weights of the organic feedstock and the at least onestarch matrix is between 20% and 60%. In yet another aspect of the invention, in the blended organic feedstock: the weight of the at least one plasticizer to the total weight of the blended organic feedstock and starch is 30% or lower. In another aspect of the invention, in the blended organic feedstock: the weight of the at least one plasticizer to the total weight of the blended organic feedstock is around 20% or lower.

[0018] In another aspect of the invention, each of the at least one starch matrix is selected from the group consisting of com starch, tapioca, potato starch, and casava. In another aspect of the invention, each of the at least one plasticizer is selected from the group consisting of glycerol, sorbitol, xylitol, mannitol, erythritol, polyethylene glycol (PEG), propylene glycol, carboxylic acids.

[0019] In another aspect of the invention, each of the at least one catalyst is a metal ion. In another aspect of the invention, each of the at least one catalyst is selected from the group consisting of metal ions sourced from calcium chloride, iron chloride, magnesium chloride, potassium chloride, sodium chloride, zinc chloride, calcium carbonate, ferrous carbonate, magnesium carbonate, sodium carbonate, zinc carbonate, sodium bicarbonate, potassium bicarbonate, calcium phosphate, calcium sulfate, ferrous sulfate, ferric sulfate, magnesium sulfate, potassium sulfate, zinc sulfate, and zinc acetate.

[0020] In another aspect of the invention, the extrusion reactor is operated at a temperature between around 50 °C + / - 5 °C and around 180 °C + / - 5 °C, a pressure at die between 200 psi + / - 5 psi and 1500 psi + / - 5 psi, torque at 20% + / - 2 % to 90% + / - 2% of extruder maximum, and a shear rate of 50 + / - 5 to 900 + / - 5 rotations per second.

[0021] In another aspect of the invention, the at least one starch matrix, at least one plasticizer, at least one catalyst, the temperature of the extrusion reactor, the pressure at die of the extrusion reactor, the torque of the extrusion reactor, and the rotational rate of the extrusion reactor are chosen based on analysis of the lipids, proteins, fatty acids, hemicellulose, cellulose, and lignin of the organic feedstock.

[0022] In another aspect of the invention, the at least one starch matrix, at least one plasticizer, at least one catalyst, the temperature of the extrusion reactor, the pressure atdie of the extrusion reactor, the torque of the extrusion reactor, and the rotational rate of and the rotational rate of the extrusion reactor are chosen based on analysis of the lipids, proteins, fatty acids, hemicellulose, cellulose, and lignin of the organic feedstock, and on the desired properties of the resulting bioplastic.

[0023] In another aspect of the invention, the at least one catalyst includes Group One metal ions. In still another aspect of the invention, the at least one catalyst includes Group 2 and Group 3 metal ions.

[0024] In another aspect of the invention, the extrusion reactor is configured so the blended organic feedstock is processed through a first zone and a second zone, where at least one of the temperature of the extrusion reactor, the pressure at die of the extrusion reactor, the torque of the extrusion reactor, and the rotational rate of the extrusion reactor in the second zone is different from the temperature of the extrusion reactor, the pressure at die of the extrusion reactor, the torque of the extrusion reactor, and the rotational rate of the extrusion reactor in the first zone.

[0025] In another aspect of the invention, the extrusion reactor is configured so the blended organic feedstock is processed through a third zone, where at least one of the temperature of the extrusion reactor, the pressure at die of the extrusion reactor, the torque of the extrusion reactor, and the rotational rate of the extrusion reactor in the third zone is different from the temperature of the extrusion reactor, the pressure at die of the extrusion reactor, the torque of the extrusion reactor, and the rotational rate of the extrusion reactor in the first zone and at least one of the temperature of the extrusion reactor, the pressure at die of the extrusion reactor, the torque of the extrusion reactor, and the rotational rate of the extrusion reactor in the third zone is different from the temperature of the extrusion reactor, the pressure at die of the extrusion reactor, the torque of the extrusion reactor, and the rotational rate of the extrusion reactor in the second zone.BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Embodiments herein will hereinafter be described in conjunction with the appended drawings provided to illustrate and not to limit the scope of the claims, wherein like designations denote like elements, and in which:

[0027] Figure 1 is an illustration of the pre-processing of organic waste; and

[0028] Figure 2 illustrates the reactive extrusion stage of the process, as well as post- reactive extrusion processing.DETAILED DESCRIPTION OF THE INVENTION

[0029] The method described herein produces bioplastics from an organic feedstock, specifically from organic agricultural waste and food waste, such as, but not limited to, fruit peel waste derived from the juice, smoothie, and food processing industries. This feedstock includes peels from fruits, such as oranges, bananas, mangoes, and apples, which are rich in valuable bioactive compounds like polyphenols, flavonoids, and essential oils.

[0030] Figure 1 is an illustration of the pre-processing of organic waste. Turning to Figure 1 , there is the collection 10 of organic food waste, for example fruit peels sourced from juice and smoothie production facilities. This organic waste is then washed in step 12. In a preferred embodiment, there is a step 14, where the organic waste is shredded. The organic waste is then milled in step 16. In a preferred embodiment, the organic waste after milling has a particle size equal or less than around 750 microns (where around means + / - 5 microns). In another preferred embodiment, the organic waste is then dried in step 18.

[0031] Optional step 14, shredding, allows for more efficient milling in step 16. Step 18, drying, allows for more efficient subsequent reactions.

[0032] In step 20, the organic waste is mixed with at least one catalyst, at least one plasticizer, and at least one starch to produce a blended organic feedstock. The resulting blended organic feedstock should be a homogeneous mixture, with an even distribution of milled organic waste, catalyst(s), starch(es) and plasticizer(s). The blended organic feedstock is preferably stored (step 22) until used in a reactive extrusion process.

[0033] In step 24, the blended organic feedstock is fed into a reactive extruder.

[0034] Figure 2 illustrates the reactive extrusion stage of the process, as well as post- reactive extrusion processing. Turning to Figure 2, in step 200 the blended mixture is fed into a reactive extruder, where mechanical and thermal processing initiates the polymerization of the bioplastic. Parameters such as operating temperature, pressure at the die, torque, and shear rate, are controlled to set processing conditions. Within the extruder, mechanical shear generated by rotating screws effectively breaks down starch and organic waste, facilitating the in-situ extraction of bioactive compounds and promoting polymer chain formation.

[0035] The temperature in the reactive extruder is maintained between 80°C + / - 5 °C and 180°C + / - 5 °C to optimize or improve both the extraction and polymerization processes. Precise adjustments to rotational speed, torque, and pressure are critical, as they ensure that the catalyst provides optimal active sites for the target reactions involved in the cascade process. This meticulous control leads to stable reactions and the production of high- quality bioplastics.

[0036] In step 202, in-situ polymerization takes place within the extruder. The in-situ polymerization process integrates mechanical shear, thermal energy, pressure, and residence time to transform the feedstock into a cohesive bioplastic material characterized by structural integrity and biodegradability. The high shear forces enhance the interfacial contact between bioactive compounds and starch, while controlled temperatures promote necessary chemical reactions. The blended organic waste is directly introduced into the extruder, effectively minimizing or reducing the need for separate extraction methods. Simultaneously, the biodegradable starch matrix ensures interaction between the materials. The catalyst(s), when applied under specific extrusion conditions, provide thenecessary active sites to facilitate the in-situ extraction of bioactive compounds without the use of harmful solvents. This approach significantly enhances sustainability and efficiency in bioplastic production.

[0037] As polymerization occurs, conditions such as temperature, pressure, and shear rate are continuously monitored and adjusted to achieve the desired properties of the final bioplastic (illustrated as step 204).

[0038] This advanced extrusion method results in a cohesive, eco friendly bioplastic that is compostable and serves as a sustainable alternative to conventional plastics.

[0039] After extrusion, the hot bioplastic is rapidly cooled (step 206) to stabilize its structure. This cooling process should be controlled so as to prevent internal stresses. The cooled extrudate may then be shaped into films, sheets, pellets, or complex molded parts using various techniques, ensuring that the final products meet specific mechanical, thermal, and biodegradable properties suitable for diverse applications such as packaging and consumer goods.

[0040] In a preferred embodiment, the blended organic waste is processed through two or more zones in the reactive extruder. Each zone can have individually controlled processing conditions, including different operating temperatures (in a further preferred embodiment, between around 50 °C + / - 5 °C and 180 °C + / - 5 °C), pressures at the die head (in a further preferred embodiment, from around 200 PSI + / - 5 PSI to around 1500 PSI + / - 5 PSI), shear rate (in a further preferred embodiment, from around 50 + / - 5 to around 900 + / - 5 rotations per second), and torque (in a further preferred embodiment, torque from around 20% + / - 2 % to around 90% + / - 2 % of extruder maximum).

[0041] In the method described above, the at least one catalyst(s) are metal ions. In a preferred embodiment, the metal ions are sourced from calcium chloride, iron chloride, magnesium chloride, potassium chloride, sodium chloride, zinc chloride, calcium carbonate, ferrous carbonate, magnesium carbonate, sodium carbonate, zinc carbonate, sodium bicarbonate, potassium bicarbonate, calcium phosphate, calcium sulfate, ferroussulfate, ferric sulfate, magnesium sulfate, potassium sulfate, zinc sulfate, and zinc acetate.

[0042] In a preferred embodiment, the plasticizer(s) are selected from the group consisting of glycerol, sorbitol, xylitol, mannitol, erythritol, polyethylene glycol (PEG), propylene glycol, carboxylic acids.

[0043] In a preferred embodiment, the starches are selected from the group consisting of corn starch, tapioca, potato starch, and casava. In another preferred embodiment, the starches are sourced from: cereal grains (corn, rice, wheat, barley, sorghum); root and tuber crops (potato, cassava, sweet potato, yam); legumes I pulses (pea, mung bean, lentil, chickpea); and fruit seeds (jackfruit seed, mango seed kernel, avocado seed, durian seed, tamarind seed).

[0044] As the process involves using starch as the backbone of the resulting bioplastic, the raw organic waste should not contain biodegradable resin or other materials that would interfere with the process.

[0045] In a preferred embodiment, the weight of organic feedstock to the sum of the weights of the organic feedstock and the at least one starch matrix is between around 25% and around 75%; the weight of the at least one catalyst to the total weight of the blended organic feedstock is 20% or lower; and the weight of the at least one plasticizer to the total weight of the blended organic feedstock is around 40% or lower.

[0046] In another preferred embodiment, the weight of organic feedstock to the sum of the weights of the organic feedstock and the at least one starch matrix is between around 40% and around 60%.

[0047] In another preferred embodiment, the weight of the at least one plasticizer to the total weight of the blended organic feedstock is around 30% or lower. In another more preferred embodiment, the weight of the at least one plasticizer to the total weight of the blended organic feedstock is around 20% or lower.

[0048] In a preferred embodiment, the reactive extruder is operated at a temperature between around 50 °C and around 180 °C, a pressure at die between around 200 psi and around 1500 psi, torque at around 20% to around 90% of extruder maximum (the percentage would depend upon what the extruder maximum is and the amount of desired torque), and a shear rate of around 50 to around 900 rotations per second. «AROUND»

[0049] In practice, the exact choice of catalyst(s), starch(es) and plasticizer(s), their weight ratios in the blended mix, and the settings for the reactive extrusion process are set based on an understanding of the chemical analysis of the raw organic feedstock (lipids, proteins, fatty acids, hemicellulose, cellulose, and lignin) and the desired properties of the resulting bioplastic.

[0050] Starches are generally comprised of two types of polymers: amylose and amylopectin. The higher the percentage of amylose in the starch(es) used in the blended organic waste, a higher amount of energy needs to be put into the blend and / or a higher percentage of plasticizer needs to be put into the blend to maintain homogenous blending and avoid phase separation. Higher amounts of energy can be achieved by adjusting the settings of the reactive extrusion device by increasing the temperature, or increasing the shear rate, or increasing the torque.

[0051] The choice of amylose versus amylopectin in the starch(es) in the blended organic waste also affects the strength and rigidity of the resulting bioplastic. Using amylose-rich starch(es) results in a bioplastic that is rigid. Using amylopectin rich starch(es) results in a bioplastic that is flexible. The f lexibi I ity / rigid ity of the resulting bioplastic can be adjusted by adjusting the ratio of amylose-rich to amylopectin-rich starch in the blended feedstock.

[0052] The higher the percentage of protein and lipids (including fatty acids, organic acids and polyphenols) in the raw organic waste, the more catalyst needs to be used in the blended organic waste to encourage cross-linking with these bioactive materials.

[0053] The type of catalyst also affects the strength and rigidity of the resulting bioplastic. The use of group one metal ions promotes more cross-linking in the resulting bioplastic,increasing the stability and tensile strength of the resulting bioplastic. The use of group two and group three metal ions results in less cross-linking, and so these catalysts are appropriate when a bioplastic with superior elongation or flexibility properties is desired.

[0054] The higher the fibre content (the combination of cellulose, hemicellulose, and lignin) in the raw organic waste, the greater the amount of mechanical energy in the reactive extruder needed for proper dispersion. This can be achieved by changing the shear rate, torque, and / or screw configuration in the reactive extruder. A high enough fibre content in the raw organic material renders the process described herein of lesser practicality, and so this method is preferably used for food and agricultural waste (which has a high content of protein, lipids, polyphenomes, and tannins), and only less preferably used for pulp and paper waste, which tends to be high in fibre content.

[0055] EXAMPLES

[0056] Example 1 : A bioplastic composition developed from orange peel waste combined with a corn starch matrix, engineered for flexible applications. The material is designed with tensile strength between 3 MPa - 10 MPa and elongation of 70% to 300%. This bioplastic has been created using the methods disclosed in this example, and the resulting bioplastics had the designed tensile strength and elongation.

[0057] This example outlines the formulation and processing of a bioplastic material derived from a synergistic mixture of organic agro-food waste and a starch (polysaccharide) matrix. The composition includes the following key components:

[0058] (A) Orange peel: Rich in bioactive compounds such as flavonoids, essential oils, and dietary fibers, orange peel serves as a sustainable organic waste source. Its bioactive content contributes to enhancing the biodegradability of the bioplastic and improving its mechanical properties, such as tensile strength and elasticity. The inclusion of orange peel also ensures efficient use of agro-industrial waste, addressing circular economy principles by converting waste into value-added materials.

[0059] (B) Corn starch: Acting as the primary polymer matrix, com starch undergoes thermoplasticization, where its granule structure is destructured to form a malleable thermoplastic starch (TPS). This enables the formation of films and flexible materials. Starch also contributes to the overall strength of the material, supporting film integrity, mechanical durability, and compostability.

[0060] (C) Plasticizers: A blend of polyols (e.g., glycerol, sorbitol, xylitol, mannitol, erythritol, polyethylene glycol) [PEG], and propylene glycol) and carboxylic acids (e.g., adipic acid, azelaic acid, benzoic acid, tartaric acid, malic acid, citric acid, succinic acid, sebacic acid, lactic acid, acetic acid) is added to enhance flexibility and processability. Polyols facilitate the transformation of granular starch into a homogeneous thermoplastic phase, making it more processable at lower temperatures, while carboxylic acids serve a dual role as plasticizers and crosslinking agents, stabilizing the polymer network and improving thermal and mechanical properties.

[0061] (D) Catalyst: A proprietary catalytic system composed of metal ion salts (e.g. calcium chloride, iron chloride, magnesium chloride, potassium chloride, sodium chloride, zinc chloride, calcium carbonate, ferrous carbonate, magnesium carbonate, sodium carbonate, zinc carbonate, sodium bicarbonate, potassium bicarbonate, calcium phosphate, calcium sulfate, ferrous sulfate, ferric sulfate, magnesium sulfate, potassium sulfate, zinc sulfate, zinc acetate) is used. This catalytic blend enhances the extraction of bioactive compounds from the orange peel during the extrusion process and promotes polymerization reactions. It also ensures efficient crosslinking, reducing the need for harmful solvents, and minimizing water and energy consumption during production.

[0062] Concentration Ranges:

[0063] Orange peel (A): The proportion of orange peel in the starch matrix (A + B) is between 5% and 75% by weight, with an optimal range of 20% to 60%. This balance ensures efficient utilization of waste materials while maintaining the mechanical integrity of the bioplastic.

[0064] Plasticizers (C): The plasticizers are added at less than 40% of the total weight (A + B + C), with preferred levels below 30%, and ideally around 20%, to balance flexibility with mechanical strength and environmental safety.

[0065] Catalyst (D): The catalyst concentration remains below 20% of the total composition (A + B + C + D), preferably under 10%, ensuring optimal catalytic efficiency while complying with environmental standards.

[0066] Processing method:

[0067] The bioplastic mixture undergoes processing in a co-rotating twin-screw extruder, where the temperature is controlled between 50°C and 180°C and broken down into up to 4 zones to optimize or improve thermal conditions for polymer processing and ensure that the material remains within its thermal stability range.

[0068] Zone 1 : Start with temperature between 50° - 100°C

[0069] Zone 2: Ramp-up with temperature between 70° - 140°C

[0070] Zone 3: In-situ extraction and reaction with temperature between 90° - 160°C

[0071] Zone 4: Extrusion with temperature between 70°-130° C

[0072] The twin-screw configuration includes conveying, mixing, reaction zones and exit zones, with specialized screw elements that facilitate both axial and radial mixing. The co- rotation of the screws ensures homogeneous blending of the bioplastic components by creating high shear and distributive mixing, promoting uniformity in molecular weight distribution and material consistency.

[0073] The screw elements, such as kneading blocks and mixing paddles, are strategically placed to enhance plasticization and promote efficient reactive extrusion. During this process, functional groups, such as hydroxyl (-OH) and carboxyl (-COOH), undergo condensation reactions, forming block copolymers and improving the structural integrity and performance of the final bioplastic. The precise control of shear and temperature further supports in-situ polymerization and incorporation of additives.

[0074] In this formulation, bioactive compounds from orange peel are in-situ extracted and incorporated into a thermoplastic starch matrix during the extrusion process, enhancing the material’s mechanical strength, biodegradability, and antimicrobial properties. The integration of these bioactive compounds occurs through reactive extrusion, where the high- energy environment facilitates the bonding of bio-compounds with the thermoplastic starch matrix, creating a functionalized bioplastic with improved rheological properties that contribute to enhanced overall performance. This process yields a bioplastic that is well- suited for a range of downstream applications, including film blowing, injection molding, and coating, with enhances mechanical performance and improved environmental compatibility.

[0075] Performance and benefits:

[0076] The bioplastic derived from this composition exhibits enhanced flexibility, improved mechanical strength, and thermal stability. The unique combination of starch, plasticizers, and the catalytic system ensures high performance while maintaining the material’s compostability and eco-friendliness. This innovation offers significant water and energy savings during production and supports the circular economy by converting waste into valuable bioplastic materials.

[0077] Example 2: A bioplastic composition formulated from a blend of orange peel and mango peel waste integrated with a com starch matrix, designed for rigid applications. The material is designed with tensile strength between 20 MPa - 40 MPa and elongation of 10% to 70%. This bioplastic has been created using the methods disclosed in this example, and the resulting bioplastics had the designed tensile strength and elongation.

[0078] This example highlights the creation of a bioplastic material incorporating a blend of orange peel and mango peel as organic feedstock in a starch (polysaccharide) matrix. The components include:

[0079] (A) Blend of orange peel and mango peel: Mango peel is rich in polyphenolic compounds, vitamins, and dietary fiber, while orange peel contributes similar bioactive elements. The combination of these agro food waste materials provides enhancedbiodegradability and additional mechanical reinforcement, while utilizing multiple waste streams for material development.

[0080] (B) Cassava starch: Cassava starch serves as the thermoplastic base, providing the structural framework of the bioplastic. Upon thermoplasticization, the starch undergoes destructurization, facilitating the formation of a flexible, malleable polymer matrix.

[0081] (C) Plasticizers: Facilitates the transformation of granular starch into a uniform thermoplastic phase, significantly enhancing processability. These plasticizers enhance the balance between flexibility and tensile strength, allowing the material to be processed under lower energy conditions.

[0082] (D) Catalyst: The catalyst system facilitates bioactive compound extraction and polymerization, promoting e icient reactive extrusion. The same mixture of metal ion salts as in Example 1 is employed to improve mechanical properties, processing efficiency, and environmental sustainability.

[0083] Concentration ranges:

[0084] Blend of orange peel and mango peel (A): The mixture of orange and mango peel constitutes 5% to 80% by weight of the starch matrix, with an optimal range of 30% to 70%. This ratio ensures adequate incorporation of bioactive compounds while maintaining the material’s structural integrity.

[0085] Plasticizers (C): Plasticizers are added at less than 30% by weight (A + B + C), preferably below 20%, and ideally around 10%, providing an optimal balance between processability and material properties.

[0086] Catalyst (D): The catalyst concentration remains below 20% by weight (A + B + C + D), with an optimal range below 10%, ensuring efficient polymerization and process control.

[0087] Processing method:

[0088] The bioplastic mixture undergoes processing in a co-rotating twin-screw extruder, where the temperature is precisely controlled between 60°C and 180°C and broken down into up to 4 zones to improve thermal conditions for polymer processing and ensure that the material remains within its thermal stability range.

[0089] Where:

[0090] Zone 1 : Start with temperature between 70° - 100°C

[0091] Zone 2: Ramp-up with temperature between 80° - 150°C

[0092] Zone 3: In-situ extraction and reaction with temperature between 110° - 170°C

[0093] Zone 4: Extrusion with temperature between 80°-150° C

[0094] The twin-screw configuration includes conveying, mixing, reaction zones and exit zones, with specialized screw elements that facilitate both axial and radial mixing. The co- rotation of the screws ensures homogeneous blending of the bioplastic components by creating high shear and distributive mixing, promoting uniformity in molecular weight distribution and material consistency.

[0095] Within the extruder, reactive extrusion plays a critical role in driving the formation of crosslinked polymer structures, enhancing the mechanical integrity of the final material. The functional groups in the starch matrix, including hydroxyl (-OH) and carboxyl (- COOH) groups, undergo chemical reactions during extrusion, leading to the formation of strong covalent bonds that contribute to the improved mechanical properties of the bioplastic. Additionally, bioactive compounds derived from mango and orange peel are incorporated into the thermoplastic starch matrix through in-situ chemical reactions during this phase. These bioactive compounds are effectively grafted onto the starch matrix, resulting in a material with enhanced tensile strength, elasticity, and flexibility.

[0096] The integration of these bioactive compounds not only enhances the mechanical performance but also imparts functional benefits such as antimicrobial properties and improved biodegradability. The resultant bioplastic is a structurally sound and environmentally friendly material, suitable for a variety of applications, includingpackaging, coatings, and films. The crosslinking formed through reactive extrusion ensures a more durable and rigid structure with enhanced thermal and mechanical stability for high- performance applications.

[0097] Performance and benefits:

[0098] This bioplastic offers enhanced biodegradability and improved mechanical properties, with increased rigidity while maintaining necessary flexibility. This balance makes it ideal for sustainable rigid packaging solutions. The dual-waste feedstock approach, utilizing orange and mango peels, highlights both the material’s environmental and economic benefits by utilizing multiple waste streams. Additionally, the process is energy- and water-efficient, further enhancing the overall sustainability of the material, while reducing reliance on resource-intensive production methods.

[0099] The bioplastic produced by the process described herein exhibits several key properties that enhance its suitability for various applications.

[0100] This bioplastic decomposes in both home and industrial composting environments within a short timeframe, ensuring that no harmful residues remain, thereby contributing to a circular economy.

[0101] The resulting bioplastic may be designed to preferably have tensile strength of 3MPa - 40MPa, elongation of 10% to 300%, and is flexible (elongation at break during the tensile test), making it ideal for packaging solutions and single-use consumer goods that require durability without compromising performance.

[0102] As the bioplastic is composed entirely of non-toxic ingredients, the bioplastic is free from harmful chemicals or solvents, ensuring safety for food contact and environmental applications while promoting sustainable practices.

[0103] The bioplastic prepared via this process can be used in several applications. The bioplastic can be tailored for both rigid and flexible packaging applications, offering a versatile alternative to conventional plastics. It can be used in food packaging, containers, and wraps, significantly reducing reliance on petroleum-based plastics andsupporting sustainability goals across various industries. It is ideal for producing compostable single-use items such as utensils, plates, cups, and shopping bags. These products break down entirely under composting conditions, eliminating the long-term waste typically associated with disposable plastics.

[0104] The bioplastic is also highly suitable for biodegradable agricultural films, containers, and seed or fertilizer coatings. Its use in these applications promotes soil health, reduces plastic pollution, and supports environmentally friendly farming practices by naturally degrading in the soil after use.

[0105] The in-situ extraction and polymerization process significantly minimizes water consumption and reduces the need for harmful solvents typically used in traditional bioplastic production methods. This reduction in resource usage not only conserves water but also lowers the environmental footprint of the manufacturing process. Additionally, the streamlined method reduces energy consumption by integrating extraction and polymerization into a single step, enhancing overall process efficiency and sustainability.

[0106] By integrating bioactive compounds from organic waste with a starch matrix, BioPolatis’ bioplastic achieves enhanced mechanical strength, flexibility, and thermal stability (measured by Thermogravimetric Analysis (TGA) to measure temperature where degradation is fastest). These enhanced properties make the bioplastic suitable for a wide range of applications, including rigid and flexible packaging, single-use consumer goods, and agricultural films, ensuring that it meets the performance requirements traditionally associated with conventional plastics.

[0107] The continuous extrusion and in-situ polymerization process allows for high- throughput manufacturing, making it feasible to produce large quantities of bioplastic efficiently. This scalability ensures that a user can meet the growing demand for eco- friendly materials without compromising on quality or sustainability, positioning the technology as a viable alternative to conventional plastic production on an industrial scale.

Claims

WHAT IS CLAIMED IS:1 . A method for the preparation of bioplastics from organic feedstock from food and agriculture sources, comprising the steps of: cleaning the organic feedstock ; milling the organic feedstock; blending the organic feedstock with at least one starch matrix, at least one plasticizer, and at least one catalyst to produce a blended organic feedstock; and extruding the blended organic feedstock using an extrusion reactor; where each of the at least one catalyst is selected from the group consisting of metalions sourced from calcium chloride, iron chloride, magnesium chloride, potassium chloride, sodium chloride, zinc chloride, calcium carbonate, ferrous carbonate, magnesium carbonate, sodium carbonate, zinc carbonate, sodium bicarbonate, potassium bicarbonate, calcium phosphate, calcium sulfate, ferrous sulfate, ferric sulfate, magnesium sulfate, potassium sulfate, zinc sulfate, and zinc acetate; and where the at least one starch matrix, at least one plasticizer, at least one catalyst, the temperature of the extrusion reactor, the pressure at die of the extrusion reactor, the torque of the extrusion reactor, and the rotational rate of the extrusion reactor are chosen based on analysis of the lipids, proteins, fatty acids, hemicellulose, cellulose, and lignin of the organic feedstock and the desired properties of the extruded blended organic feedstock.

2. The method of claim 1 , where the combined weight percentage of cellulose plus hemicellulose plus lignin in the organic feedstock is less than 30%.

3. The method of claim 2, where in the blended organic feedstock: the weight of organic feedstock to the sum of the weights of the organic feedstock and the at least one starch matrix is between 5% and 75%; the weight of the at least one catalyst to the total weight of the blended organic feedstock is 20% or lower; and the weight of the at least one plasticizer to the total weight of the blended organic feedstock is around 40% or lower.

4. The method of claim 3, where in the blended organic feedstock: the weight of organic feedstock to the sum of the weights of the organic feedstock and the at least one starch matrix is between 20% and 60%.

5. The method of claim 3, where in the blended organic feedstock: the weight of the at least one plasticizer to the total weight of the blended organic feedstock and starch is 30% or lower.

6. The method of claim 3, where in the blended organic feedstock: the weight of the at least one plasticizer to the total weight of the blended organic feedstock is 20% or lower.

7. The method of claim 3, where each of the at least one starch matrix is selected from the group consisting of corn starch, tapioca, potato starch, and casava.

8. The method of claim 7, where each of the at least one plasticizer is selected from the group consisting of glycerol, sorbitol, xylitol, mannitol, erythritol, polyethylene glycol (PEG), propylene glycol, carboxylic acids.

9. The method of claim 8, where each of the at least one catalyst is a metal ion.

10. The method of claim 9, where each of the at least one catalyst is selected from the group consisting of metalions sourced from calcium chloride, iron chloride, magnesium chloride, potassium chloride, sodium chloride, zinc chloride, calcium carbonate, ferrous carbonate, magnesium carbonate, sodium carbonate, zinc carbonate, sodium bicarbonate, potassium bicarbonate, calcium phosphate, calcium sulfate, ferrous sulfate, ferric sulfate, magnesium sulfate, potassium sulfate, zinc sulfate, and zinc acetate.11 . The method of claim 10, where the extrusion reactor is operated at a temperature between around 50 °C + / - 5 °C and around 180 °C + / - 5 °C, a pressure at die between 200psi + / - 5 psi and 1500 psi + / - 5 psi, torque at 20% + / - 2 % to 90% + / - 2% of extruder maximum, and a shear rate of 50 + / - 5 to 900 + / - 5 rotations per second.

12. The method of claim 11 , where the at least one starch matrix, at least one plasticizer, at least one catalyst, the temperature of the extrusion reactor, the pressure at die of the extrusion reactor, the torque of the extrusion reactor, and the rotational rate of the extrusion reactor are chosen based on analysis of the lipids, proteins, fatty acids, hemicellulose, cellulose, and lignin of the organic feedstock.

13. The method of claim 12, where the at least one starch matrix, at least one plasticizer, at least one catalyst, the temperature of the extrusion reactor, the pressure at die of the extrusion reactor, the torque of the extrusion reactor, and the rotational rate of and the rotational rate of the extrusion reactor are chosen based on analysis of the lipids, proteins, fatty acids, hemicellulose, cellulose, and lignin of the organic feedstock, and on the desired properties of the resulting bioplastic.

14. The method of claim 13, where the at least one catalyst includes Group One metal ions.

15. The method of claim 14, where the at least one catalyst includes Group 2 and Group 3 metal ions.

16. The method of claim 12, where the extrusion reactor is configured so the blended organic feedstock is processed through a first zone and a second zone, where at least one of the temperature of the extrusion reactor, the pressure at die of the extrusion reactor, the torque of the extrusion reactor, and the rotational rate of the extrusion reactor in the second zone is different from the temperature of the extrusion reactor, the pressure at die of the extrusion reactor, the torque of the extrusion reactor, and the rotational rate of the extrusion reactor in the first zone.

17. The method of claim 16, where the extrusion reactor is configured so the blended organic feedstock is processed through a third zone, where at least one of the temperature of the extrusion reactor, the pressure at die of the extrusion reactor, the torque of the extrusion reactor, and the rotational rate of the extrusion reactor in the third zone is different from the temperature of the extrusion reactor, the pressure at die of the extrusionreactor, the torque of the extrusion reactor, and the rotational rate of the extrusion reactor in the first zone and at least one of the temperature of the extrusion reactor, the pressure at die of the extrusion reactor, the torque of the extrusion reactor, and the rotational rate of the extrusion reactor in the third zone is different from the temperature of the extrusion reactor, the pressure at die of the extrusion reactor, the torque of the extrusion reactor, and the rotational rate of the extrusion reactor in the second zone.

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