WO2021154165A1

WO2021154165A1 - Biocomposite materials and usage areas thereof

Info

Publication number: WO2021154165A1
Application number: PCT/TR2020/050052
Authority: WO
Inventors: Müslüm ALTUN
Original assignee: Adiyaman Universitesi Rektorlugu
Priority date: 2020-01-28
Filing date: 2020-01-28
Publication date: 2021-08-05

Abstract

The invention particularly relates to biocomposite materials produced by employing biodegradable polymer (1.1) as a matrix and pistachio shell (2) and/or black cumin cake (3) as reinforcing element. The invention also relates to biocomposite material produced from biodegradable materials for use as plastic-based toys, drinking straws, injection materials and 3D printer filament materials.

Description

BIOCOMPOSITE MATERIALS AND USAGE AREAS THEREOF Technical Field

The invention particularly relates to biocomposite materials produced by employing biodegradable polymer as a matrix and pistachio shell and/or black cumin cake as reinforcing element. The invention also relates to biocomposite material produced from biodegradable materials for use as plastic-based toys, drinking straws, injection materials and 3D printer filament materials.

Prior Art

The dependence of the increasing world population on fossil-fuel based polymers is not sustainable due to exhausted fossil-fuel resources and volatile prices. This situation has created a motivation on meeting the supply of needed polymeric materials from renewable resources.

Biological based polymers and fiber or lignocellu losic materials obtained from renewable resources are suitable candidates to be substituted for petroleum based polymers. Specifically, polyhydroxyalkanoates (PHA) and polylactic acid (PLA), which are among the said biopolymers, have gained much popularity due to the fact that they can be produced from renewable resources, have properties similar to biodegradable, biocompatible and conventional polyolefins. On the other hand, it often may not be possible to use said biopolymers alone, due to their lack of sufficient thermal stability and their exceedingly crystalline and brittle structure. These problems may be solved by methods such as modifying and dopping of biopolymers, also blending them with other polymers etc., as there are many studies/patent applications in the related literature. Nowadays 3D printers have also been widely used. Several research-development studies are conducted on the improvement of 3D printers. These improvements in 3D printer technology creates the need of filament materials. Due to petroleum based polymers employed in filament materials are exhaustible entails the quest for alternative polymers. In the selection of bio-based polymers, which are acknowledged as the most popular alternative of petroleum based polymers, it is of importance that they are cost efficient, sustainable and sufficient in material properties. Various studies have been conducted for amplification of the bio-based polymers with insufficient material properties.

Yet another issue of increasing importance nowadays is plastic toys for infants/children. Plastic toys with toxic components or ingredients may be severely noxious for the health of infants/children. Toys produced as an outcome of the studies conducted are high priced so purchasable by only privileged few.

Hemp, kenaf, abaca, banana and Indian hemp for the production of bio composites are widely used in the prior art. However, among these hemps, kenaf and jute, which are annual plants, cannot sustainably meet the increasing requirement of bio composites, due to the need of land area, requirement of far too much labor and resource consumption and the competition with food production. On the other hand, abaca and banana can be planted in very limited areas of the world due to their need of special climatological conditions. Besides, all the above-mentioned natural materials after they have been reaped from the fields, are subjected to expensive, labor intensive and time consuming extraction and/or post-treatment such as decortication and/or retting.

In the state of art, while the quality of natural fibers/materials employed in biocomposite materials is affected by environmental growth conditions, plant maturity at harvest time; the mechanical properties thereof are affected by production, service life and pre-processes that are implemented. All of the above factors affect the chemical structure and composition of the fibers employed, thus determining the strength of the fibers. The required process temperature during the production of biocomposite materials result in degradation and mechanical weakening of natural fibers, which are generally sensitive to thermal treatments. Therefore, biocomposite material to be obtained cannot be produced with the preferred properties. Yet again, it is seen in the prior art that natural fibers employed in biocomposite materials generally start to lose their mechanical strength at temperatures above 170°C. On the other hand, the process temperatures widely employed in analog studies for biocomposite production may be up to 210°C. This situation significantly affects the thermal strength thus the resistance of the natural fibers employed at relatively high process temperatures.

Object of The Invention The main object of the invention is to be able to produce a biocomposite material which is resistant in mechanical properties for plastic-based toys for infants/child, injection and 3D printer filament materials. Therefore, it is an object of the invention to develop an environmentally friendly and sustainable alternative by reducing the use of petroleum based polymers.

It is another object of the invention to convert the pistachio and black cumin shells and cakes that is planted in a high proportion into high value added materials. Pistachio shell and black cumin cake are considered to be a waste and disposed. However, while these bio-based products have high mechanical properties, they can also be used as high value added materials.

Pistachio shell and black cumin cake according to invention are agricultural by products and are not in need of land area, labor, time and post-processing. With this aspect, they do not compete with food prices and may be much more cost- effective compared to equivalent products. Pistachio shell and black cumin cake can be found not only in a certain season of the year, but all the time over the year in plenty of amounts, due to their specific economical valuations, therefore their cost of storage is decreased or the loss such as self-degradation during storage is minimized. This situation makes the yet already expensive production of biocomposite materials more feasible and facilitates availability. Thus the employment of more available bio composite based materials delimits the use of conventional materials and minimizes the noxious effects on environment. The reason for this is that the biodegradation of biological based polymers amplified with natural fiber/materials in nature is more rapid compared to raw biopolymers such that this has significant importance in reducing soil and marine pollution.

While the natural materials employed in biocomposites in the state of the art generally do not have any function other than the amplification, biocomposites especially in which black cumin cake is employed according to the present invention, due to flavonoids present in black cumin cake, will also have antibacterial, anti-inflammatory and antioxidant properties; herewith it is intended to distinguish them from equivalent bio composites. Thus, bio composites to be formed require no dopping materials to be added, in order be given above mentioned properties. It is anticipated that, this makes the produced bio composites favorable especially in medical applications, food interactive material production and industry of safe toys/materials for children/infants.

Another object of the invention is to be able to produce bio composite material with the natural fiber reinforcing element which does not lose its mechanical properties at temperature up to 210°C during production processes.

Detailed Description of Invention

Hereinafter following reference numbers will be referred in disclosure for a better understanding of biocomposite material according to invention. Reference numbers are stated as following;

1. Polymer matrix

1.1. Biodegradable polymer

2. Pistachio shell

3. Black cumin cake

4. Nucleating agent

5. Plasticizer

6. Free radical initiator

7. Grafting agent Bio composite material according to invention consists primarily of biopolymer matrix (1), pistachio shell (2) and/or black cumin cake (3) as natural reinforcement, free radical initiator (6) and grafting agent (7).

In the laboratory studies, the results obtained by thermogravimetric analysis (TGA), after a moisture loss of 5% by weight of black cumin cake (3) around 90 - 100°C, it may be observed a weight loss of 10% in black cumin pulp (3) over around 220°C.

Similarly, in thermogravimetric analysis (TGA) for pistachio shell (2), after a moisture loss of approximately %5 around 30°C, it is seen the thermal degradation which is to affect the mechanical strength of natural fiber starts only over approximately 300°C.

When it is taken account in the context of present suggested patent application that a maximum temperature of 210°C will be employed for the production process for producing biocomposite, it is understood clearly how suitable candidates are pistachio shell (2) and black cumin cake (3) as amplifier natural fibers for biocomposites. In addition, thermal strength of said pistachio shell (2) and black cumin cake (3) within the biodegradable polymer (1.1) matrix will be amplified by implementing surface treatments to pistachio shell (2) and black cumin cake (3) to be employed in the study and they will present no weakness in mechanical properties during use.

The polymer matrix (1) of the biocomposite material is prepared using one of polymers selected from the group of biodegradable polymers (1.1) comprising polyhydroxyalkanoate, polylactic acid, polybutylene adipate-co-teraphthalate, polybutylene succinate-co-adipate, polybutylene succinate, polycaprolactone, polyglycolic acid, polylactide-co-glycoside or different mixed combinations thereof. Biopolymer matrix (1) consists of at least 50% by weight of the biocomposite material produced. At least one biodegradable polymer (1.1) is selected for the biopolymer matrix (1) and it is modified by using free radical initiator (6) and grafting agent (7). The grafting agents (7) are selected from the group consisting of methacrylate, anhydride compounds or derivatives thereof. Grafting agent (7) which is between 1-20% by weight of biodegradable polymer (1.1) to be grafted is used.

Free radical initiator (6) is selected from organic peroxy compounds or azo compounds. Free radical initiator (6) which is from 0,1 to 3% by weight of said biodegradable polymer (1.1) selected for biocomposite material (1) is mixed.

The chemical modification of the biodegradable polymer (1.1) with free radical initiator (6) and the grafting agent (7) is conducted by reactive melt process in the range of 50 - 150 rpm at temperatures of 150 - 210°C for 5 - 20 minutes in suitable mechanical mixing apparatus.

Pistachio shell (2) and/or black cumin cake (3) selected as natural amplifier and filler material are washed with purified water to remove water soluble pollutant followed by drying under vacuum. Pistachio shell (2) and/or black cumin pulp (3) with being removed from moisture are ground to size of 25 - 250 pm. Dried pistachio shell (2) and/or black cumin cake (3) are subjected to surface treatments such as alkalization and/or silanization. The pistachio shell (2) and/or black cumin cake (3) are then dried under vacuum.

Biodegradable polymer (1.1) modified with free radical initiator (6) and grafting agent (7), and pistachio shell (2) and/or black cumin cake (3), which are subjected to surface treatment and micron-sized, are mixed at 50 - 150 rpm and at temperatures of 150 - 210°C for 5 - 20 minutes in suitable mechanical mixing apparatus. Preferably, plasticizer (5) which is from 0 to 30% by weight of the biodegradable polymer (1.1) matrix can be added to this mixture. Plasticizers (5) may comprise such as, but not limited to; alkyl citrates, polyethylene glycol derivatives, glycerol, glycerol triacetates. The nucleating agent (4) which is from 0 to 2% by weight of the biodegradable polymer (1.1) matrix is then added. Nucleating agents (4) may comprise such as, but not limited to; clay, carbon nano tube, boron nitrite, talc, hydroxyapatite, calcium phosphate, zinc stearates. Similarly, additives such as; binding agents, coupling agents, chain extenders and compatibilizers are preferably added to the mixture according to the properties of the desired product.

The final bio composite material is optionally made into a filament with a diameter of 1.75/2.85 mm by a single/double screw extruder. Alternatively, the obtained bio composite material may be in the form of pellets, granules, layers, injection molded solid product, extruded solid product, pressure molded solid product, thermoformed solid product. These solid products obtained can be used, if desired, as plastic based toys for infants/children depending on their non-toxic properties, and drinking straws and optionally as injection material and 3D printer filament material.

Claims

1. Biocomposite material characterized in that it comprises; a. biodegradable polymer (1.1) which is at least 50% by weight of the biocomposite material, b. pistachio shell (2) and/or black cumin cake (3) which is maximum 50% by weight of the biocomposite material, c. grafting agent (7) which is between 1 and 20% by weight of the said biodegradable polymer (1.1), d. free radical initiator (6) which is from 0,1 to 3% by weight of the said biodegradable polymer (1.1), e. plasticizer (5) which is from 0 to 30% by weight of said biodegradable polymer (1.1), and f. nucleating agent (4) which is from 0 to 2% by weight the of said biodegradable polymer (1.1).

2. Suitable portion of pistachio shell (2) and/or black cumin cake (3) according to claim 1, characterized in that; after drying and milling processes, said pistachio shell (2) and/or black cumin cake (3) have dimensions between 25 and 250 pm.