A method for the production of bioplastics from apricot kernel shell powder and a bioplastic obtained with this method

Abstract

The invention relates to a method for the production of bioplastics from apricot kernel shell powder and to a bioplastic obtained with this method, suitable for use in various technical fields.

Description

[0001] A METHOD FOR THE PRODUCTION OF BIOPLASTICS FROM APRICOT KERNEL SHELL POWDER AND A BIOPLASTIC OBTAINED WITH THIS METHOD

[0002] TECHNICAL FIELD

[0003] The invention relates to a method for the production of bioplastics from apricot kernel shell powder and to a bioplastic obtained with this method, suitable for use in various technical fields.

[0004] PRIOR ART

[0005] Bioplastic is a type of plastic derived from natural resources or produced by biological processes. While conventional plastics are produced from raw materials derived from fossil fuels, generally oil and natural gas, bioplastics are derived from bio-resources. Bioplastics have technical advantages over conventional plastics such as being derived from renewable resources, having a low carbon footprint, and being biodegradable materials, and due to these properties, they have recently been used as raw materials in many different technical applications.

[0006] The most commonly used bioplastic raw materials are corn, sugar cane, potatoes, oats, sugar beet, rice and similar plants. In addition to these, raw materials containing starch and cellulose can also be used for obtaining bioplastics.

[0007] The fact that the components used as raw materials for obtaining bioplastics are generally selected from waste materials allows costs to be reduced and waste to be transformed into value-added products by being incorporated back into a sustainable production flow. In this way, technical problems arising from waste can also be avoided.

[0008] Based on all the technical teachings mentioned here, there are ongoing studies to utilize waste plant raw materials for obtaining bioplastics and to offer additional technical teachings for the technical field.

[0009] One can refer to the subject of the invention with the patent number KR20220046912 A as one of the studies on this topic. The said invention relates to a bioplastic comprising lignocellulosic biomass and starch-based biomass, and to a method for producing such bioplastic. Accordingly, the invention may comprise at least one or a mixture thereof selected from rice husk, soybean stem, wheat stem, jade stem, rice bran, wheat bran, reed, mugwort, bamboo, wood flour, coffee flour, soybean flour, wood fibers, cotton fibers, grass fibers as lignocellulosic biomass.

[0010] Those skilled in the relevant technical field continue to carry out research and development activities for new raw materials to be used for obtaining bioplastics, which contain components allowing bioplastics to be obtained with high efficiency. As a result, it is expected that the research and development of new raw materials that would offer additional technical solutions and advantages in the production of bioplastics for the relevant technical field will provide innovation.

[0011] SUMMARY OF THE INVENTION

[0012] Currently, technical problems related to the use and production of conventional plastic materials, as well as the depletion of natural resources, are under discussion. Therefore, it has been concluded that it is necessary to research and develop final plastic products that are biodegradable in nature and do not cause any technical drawbacks on human and environmental health during their production and use.

[0013] In response to these technical drawbacks, obtaining bioplastics has recently become a viable alternative to conventional petroleum-derived plastic materials. Many people skilled in the art conduct studies for obtaining sustainable bioplastic products with optimal cost-effectiveness and mechanical properties. The present invention provides a bioplastic production method within the said bioplastic technical field and a bioplastic obtained with the method.

[0014] The primary object of the invention is to provide a method for the production of a bioplastic with suitable mechanical properties, which is biodegradable and has no technical drawbacks for human-environmental health.

[0015] A further primary object of the invention is to provide a method for obtaining a sustainable and cost-effective bioplastic. DETAILED DESCRIPTION OF THE INVENTION

[0016] In this detailed description, the subject of the invention relates to a method for the production of bioplastics and is only described by way of examples without any limiting effect for a better understanding of the subject.

[0017] In the method according to the invention, the kernel shells obtained from apricot fruits are used as raw material. The method according to the invention enables the use of kernel shells obtained from apricot fruits as raw material in the production of bioplastics and the production of bioplastics with the characterized process steps.

[0018] The reason for using apricot kernel shell as raw material for obtaining bioplastics in the invention is that it contains high amounts of cellulose, pectic and dietary fiber derivatives. It has been recognized by the present inventors that apricot kernel shell is a good source of lignocellulose due to these properties. It is known by those skilled in the relevant technical field that the raw materials to be used for the production of bioplastics must be a good source of lignocellulose. Accordingly, one of the technical solutions that the present invention will offer for the relevant technical field is to provide a new source of lignocellulose enabling the production of bioplastics. As it is known, cellulose and lignins are separated from lignocellulose sources by chemical and physical processes, and the celluloses obtained serve as components to be used in the production of bioplastics. This cellulose can be polymerized to become the material used in the production of bioplastics.

[0019] The subject of the invention relates to a method for obtaining bioplastics from apricot kernel shells to be used as the said lignocellulose source, and the process steps of the said production method are characterized below:

[0020] - applying pre-treatments to the apricot kernel shell and performing the drying processes,

[0021] - grinding the apricot kernel shells obtained after the drying process and obtaining the powder form of the apricot kernel shells,

[0022] - preparing mixture 1 by mixing at least one selected from the group of glucose, starch, cellulose, polylactic acid, polyhydroxyalkanoates, lactic acid in at least one solvent in predetermined ratios, - adding the apricot kernel shells in powder form to the prepared mixture 1 in predetermined ratios and obtaining mixture 2,

[0023] - adding at least one alcohol-based component to the obtained mixture 2 in predetermined ratios,

[0024] - adding at least one pH regulator to the obtained mixture 2 and ensuring that the pH value is between 7 to 8,

[0025] - obtaining mixture 3 from a polyacrylic acid and at least one amide-based compound in predetermined ratios in a separate reaction medium,

[0026] - adding an ammonium persulfate solution to the obtained mixture 3 in predetermined ratios and performing the mixing processes,

[0027] - adding glycerol to the obtained mixture 3 in predetermined ratios,

[0028] - adding the obtained mixture 2 into mixture 3 obtained at the end of the processes and obtaining the target product bioplastic as a result of performing the mixing processes.

[0029] Pre-treatments of the apricot kernel shells include all the processes of cleaning, rinsing and making them suitable for the next processing steps after the said apricot kernels are received as waste. The drying process performed after the pre-treatments is preferably carried out by means of a furnace. The temperature of the said drying process step is a value between 80 to 100 °C. The duration of the drying process step is between 3 to 4 hours.

[0030] Preferably, mechanical grinders can be used to pulverize the dried apricot kernel shells. The powder size of the apricot kernel shells in powder form obtained as a result of the processes herein is expected to be at a value between 40 to 80 mesh. The powder size of the said apricot kernel shells in powder form is at the values determined as a result of the research and development activities. Especially in this range of values, the powder to be obtained from apricot kernel shells is within the value range determined to ensure a good adhesion for the bioplastic product. In addition, it can be ensured that the bioplastic product has good processability, mechanical strength properties and homogeneity within the said value range. It was determined that the targeted adhesion performance, processability and mechanical properties could not be achieved when the size is below or above these values.

[0031] In the process step of preparing mixture 1 , at least one from the group of water, isopropyl alcohol, acetonitrile, ethyl acetate, citric acid is preferably used as solvent. In the process step of preparing mixture 1 , at least one selected from the group of glucose, starch, cellulose, polylactic acid, polyhydroxyalkanoates, lactic acid is preferably used. At least one selected from the said group of glucose, starch, cellulose, polylactic acid, polyhydroxyalkanoates, lactic acid is included as the main component forming the polymer matrix for obtaining the final product bioplastics. Glucose or starch forms the building blocks of the polymer matrix through the polymerization reaction or thermoplastic process. It is one of the main factors determining the durability, mechanical properties and formability of the bioplastic material.

[0032] Mixture 1 contains glucose or starch-solvent components at a value between 1 :10 to 1 :2 g / ml, preferably as at least one selected from the group of glucose, starch, cellulose, polylactic acid, polyhydroxyalkanoates, lactic acid:solvent. The said ratios are critical as they will directly affect the processability, durability, water resistance, mechanical properties of the bioplastic, i.e. the final properties of the material.

[0033] In the process step of preparing mixture 2, the apricot kernel shell is added to mixture 1 (as apricot kernel shell powder:mixture 1 ) at a value between 1 :12 to 1 :5 g / ml. The ratios determined herein are important for material homogeneity, material strength, water absorption and solubility, and processability of the material.

[0034] In the process step of preparing mixture 2, glycerol is preferably added as the said alcohol-based component. It has an important role in imparting properties such as flexibility, bendability, water retention capacity, elasticity, degradability and environmental compatibility to the bioplastic material. The said glycerol is preferably present in mixture 2 at a value in the range of 1 :10 to 1 :2 g / ml, as glycerokmixture 2. The amount of glycerol directly affects the properties of the bioplastic. Higher glycerol ratios increase the flexibility of the material and at lower ratios the material can be more rigid.

[0035] Mixture 3 preferably contains a polyacrylic acid and at least one amide-based compound. In a preferred embodiment, at least one of methylenebisacrylamide and / or acrylamide compounds is included as the amide compound. In a preferred embodiment, both of the said amide compounds are included. In the formation of the polymer chain, it makes the polymer matrix more rigid and durable. Mixture 3 contains polyacrylic acid and at least one compound comprising the amide functional group at a value in the range of 1 :10 to 1 :25 g / g, as polyacrylic acid:at least one compound comprising amide by weight. Considering the environmental impact of these synthetic polymers used in bioplastics production, they are used at this ratio to achieve the desired properties and to improve the overall performance of the bioplastic.

[0036] Ammonium persulfate, potassium persulfate, azobisisobutyronitrile, hydrogen peroxide added to mixture 3 are included at a value in the range of 1 :55 to 1 :45 g / g, as ammonium persulfate:polyacrylic acid by weight. Ammonium persulfate acts as an initiator in bioplastics production. It initiates the polymerization reaction and increases the reaction rate.

[0037] In the ammonium persulfate solution to be included in mixture 3, ammonium persulfate is at a value in the range of 1 :300 to 1 :500 g / ml, as ammonium persulfate:solvent. These ratios are important for reaction rate, homogeneity and safety. It should be used safely to initiate the polymer reaction, to ensure a homogeneous mixture with other components used in bioplastic production, at the correct solvent ratio and under appropriate conditions. Excessive amounts of ammonium persulfate or the incorrect solvent ratio can cause dangerous reactions and the targeted product cannot be obtained.

[0038] The process temperature of the mixing process applied to obtain mixture 3 is preferably a value in the range of 40 to 75 °C. The said mixing process preferably continues for at least 30 minutes at the said temperature values. These parameters provide suitable conditions to ensure that the polymerization reaction takes place efficiently. Low temperature decreases the reaction rate, while high temperature increases the reaction rate but may increase the risk of side reactions. When the process time is too short, the polymerization may not be completed, and when it is too long, the reaction proceeds too far, increasing the risk of side reactions and wasting energy and time.

[0039] The glycerol component added in the processes of obtaining mixture 3 is at a value in the range of 1 :2 to 1.5:1 ml / ml as glycerol :polyacrylic acid in mixture 3. These components have an impact on the properties of the bioplastic material, such as mechanical properties, flexibility, durability and thermal stability. The mixing ratio is adjusted to ensure that the material has the desired properties. Different ratios change the properties of the material such as rigidity, elasticity, fracture strength and biodegradability.

[0040] After obtaining mixture 3, in a preferred embodiment, a heating process can be applied for at least 10 minutes in a pressing machine. This allows the material to soften or become flexible, thus enabling the desired shape to be formed and the adhesive properties of the material to be activated to strengthen the bond. This step is carried out to stabilize the material, that is, to evaporate the water in the material, to allow the material to take the desired shape, to activate the adhesive properties of the material, to dry the dyes, inks or coatings added to the material during the process. The temperature of the said pressing machine herein is a value in the range of 120°C-200°C.

[0041] In the process step of adding mixture 3 and mixture 2 to each other to be used for obtaining the final product bioplastic, mixture 2 is added to mixture 3 at a value in the range of 1 :2 to 1.5:1 as mixture 2:mixture 3. These values were chosen because the products with mechanical strength properties equivalent to the plastic materials frequently used in the art can be obtained within the given value ranges.

[0042] In another aspect, the invention relates to a bioplastic obtained with the characterized production method. The bioplastic obtained is a cost-effective product with strength values equivalent to the plastics frequently used in the art. This feature allows it to be used in many technical fields. The bioplastic obtained can be used in packaging, agriculture, textile and medical application sectors.

[0043] The apricot kernel shells used as raw material in the invention are, as expected, a waste material. Using these waste materials as raw materials in a value-added product reduces the costs of the final product. In addition, problems such as disposal and storage of waste are eliminated.

[0044] The protection scope of the invention is set out in the appended claims and shall in no way be limited to what is described in this detailed description for illustrative purposes. Indeed, it is clear that a person skilled in the art can come up with similar embodiments in light of the foregoing description without departing from the main theme of the invention.

Claims

CLAIMS1. A method for the production of a bioplastic, characterized in that it comprises the process steps of:- performing drying processes on the apricot kernel shell,- grinding the apricot kernel shells obtained after the drying process and obtaining the powder form of the apricot kernel shells,- preparing mixture 1 by mixing at least one selected from the group of glucose, starch, cellulose, polylactic acid, polyhydroxyalkanoates, lactic acid in at least one solvent in predetermined ratios,- adding the apricot kernel shells in powder form to the prepared mixture 1 in predetermined ratios and obtaining mixture 2,- adding at least one component to the obtained mixture 2 in predetermined alcohol-based ratios,- adding at least one pH regulator to the obtained mixture 2 and ensuring that the pH value is between 7 to 8,- obtaining mixture 3 from a polyacrylic acid and at least one amide-based compound in predetermined ratios in a separate reaction medium,- adding an ammonium persulfate solution to the obtained mixture 3 in predetermined ratios and performing the mixing processes,- adding glycerol to the obtained mixture 3 in predetermined ratios,- adding the obtained mixture 2 into mixture 3 obtained at the end of the processes and obtaining the target product bioplastic as a result of performing the mixing processes.

2. A method according to claim 1 , wherein the said drying process is carried out at a temperature value between 80 to 100 °C.

3. A method according to one of claims 1 -2, wherein the drying process is carried out for a duration at a value between 3 to 4 hours.

4. A method according to one of the preceding claims, wherein the powder size of the apricot kernel shell after the pulverization processes is at a value between 40 to 80 mesh.

5. A method according to one of the preceding claims, wherein at least one from the group of water, isopropyl alcohol, acetonitrile, ethyl acetate, citric acid is preferably used as solvent in the process step of preparing the said mixture 1 .

6. A method according to one of the preceding claims, wherein mixture 1 contains glucose or starch-solvent components at a value between 1 :10 to 1 :2 g / ml, preferably as at least one selected from the group of glucose, starch, cellulose, polylactic acid, polyhydroxyalkanoates, lactic acid:solvent.

7. A method according to one of the preceding claims, wherein in the process step of preparing the said mixture 2, the apricot kernel shell is added to mixture 1 at a value between 1 :12 to 1 :5 g / ml, as apricot kernel shell powder:mixture 1 .

8. A method according to one of the preceding claims, wherein mixture 2 contains glycerol at a value in the range of 1 :10 to 1 :2 g / ml, as glycerokmixture 2.

9. A method according to one of the preceding claims, wherein the said mixture 3 contains at least one of methylenebisacrylamide and / or acrylamide compounds as an amide compound.

10. A method according to one of the preceding claims, wherein mixture 3 contains polyacrylic acid and at least one compound comprising the amide functional group at a value in the range of 1 :10 to 1 :25 g / g, as polyacrylic acid:at least one compound comprising amide by weight.11 . A method according to one of the preceding claims, wherein mixture 3 contains ammonium persulfate at a value in the range of 1 :55 to 1 :45 g / g, as ammonium persulfate:polyacrylic acid by weight.

12. A method according to one of the preceding claims, wherein in the ammonium persulfate solution to be included in mixture 3, ammonium persulfate is at a value in the range of 1 :300 to 1 :500 g / ml, as ammonium persulfate:solvent.

13. A method according to one of the preceding claims, wherein the process temperature of the mixing process applied to obtain mixture 3 is at a value in the range of 40 to 75 °C.

14. A method according to one of the preceding claims, wherein the mixing process applied to obtain mixture 3 is carried out for a process duration of at least 30 minutes.

15. A method according to one of the preceding claims, wherein the glycerol component added in the processes of obtaining mixture 3 is at a value in the range of 1 :2 to 1 .5:1 ml / ml as glycerokpolyacrylic acid in mixture 3.

16. A method according to one of the preceding claims, wherein in the process step of adding mixture 3 and mixture 2 to each other to be used for obtaining the final product bioplastic, mixture 2 is added to mixture 3 at a value in the range of 1 :2 to 1 .5:1 as mixture 2:mixture 3.

17. A bioplastic product obtained with a method according to one of the preceding claims, wherein it comprises apricot kernel shells as the component and at least one selected from the group of glucose, starch, cellulose, polylactic acid, polyhydroxyalkanoates, lactic acid as an auxiliary component.