Chemicals Used in Polymeric Material Coated Waste Paper Composites ()
1. Introduction
Today, polymer materials consisting of paper, plastic and aluminum have a wide range of use as packaging materials, especially beverage cans. These materials are converted into composite materials thanks to additives and are brought to the industry as products with new different usage areas. Recycling waste materials without harm is an increasingly important issue. Plastic and paper raw materials, which are among the leading recycling materials, are essential components of composite products [1] . They can have unique advantages over solid materials such as high resistance, high hardness, low density, long durability life, high thermal stability, insulation and transmission [2] .
The composite material structure consists of fibers and matrix. Matrix of these materials does not dissolve by putting a different fiber or particulate material into it. Fibers are responsible for providing mechanical strength as reinforcement elements in composites. The matrix provides the stress transfer between the fibers. This affects the mechanical durability and chemical external effects, and forms the main structure of composite materials [3] . It protects the fibers against various chemical effects. Fiber-compatible matrixes significantly affect the harms in composite boards [4] .
Application areas where composite materials are generally used are as follows, space technology, marine industry, medicine (manufacturing of medical devices), instruments industry, construction and construction industry, and automotive industry [5] . The thermoplastic material in Tetra Pak is holding the fibers together by acting as a matrix. Tetra Pak box components made of paper plastic and aluminum material are shown in Figure 1 [6] .
Raw materials affect the process and the material properties of the manufacturing of composites affect the cost. These are the fillers and matching chemicals used.
In this research, the physical and mechanical waste paper ratios, reinforcing filler ratios, and the ratios of different adapting agents on composite materials produced from the waste paper were investigated. Various proportions of coupling chemicals and fillers have been used to bind polar paper material and nonpolar thermoplastic polymers together. Considering that there are tons of waste paper will be evaluated in Türkiye, this study is important. The silane binding mechanism is shown in Figure 2.
2. Materials and Methods
Plastic and various chemical matching substances added to Tetra Pak materials in the production of composite materials as follows, plastic material (polyethylene), Calcite, Boric Acid, Sodium Perborate Tetrahydrate (SPT), Titanate, Acetic Acid,
Maleic Anhydride Grafted Polyethylene (MAPE), Vinyltriethoxysilane (Silanyl). Filling materials, matrix and matching chemicals in the composite material produced in the study are shown in Figure 3.
2.1. Tetra Pak (TP)
Paper products supplied in small pieces were shredded in a 1 mm shredder machine and made suitable for production.
2.2. Polyethylene (PE)
Waste High Density Polyethylene (HDPE) used as polymer was obtained from commercial sources. Waste Polyethylene was preferred in this study. It is a easy to find and inexpensive material to supply.
2.3. Filling Materials
Calcite (CaCO3), used as a filler material, is abundant in nature and is used as a filling substance, paint and plastic industries. It has been preferred because it is cheap and has the significant volume to fill the gap between the reinforcement material and the polymer matrix. Boric Acid (H3BO3) is not a flammable substance
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Figure 2. Binding silane mechanism [7] .
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Figure 3. Representation of the composite material content produced.
and has flame retardant properties.
In this research, it was preferred to prevent possible burns on composite sheets to be produced under hot press.
SPT (Sodium Perborate Tetrahydrate/NaBO3∙4H2O) is in the form of powder. To reinforcement materials used, a more economical and robust material will be obtained.
2.4. Matching Chemicals
Titanate improves hydrophobicity and eliminates air pockets. MAPE (Maleic Anhydride Grafted Polyethylene) used as a compatibilizer, MAPE has been applied to improve interfacial adhesion between high density polyethylene and fiber [8] . Silanyl (Vinyltriethoxysilane C8H18O3Si) is used to bond organic polymers and inorganic reinforcement materials due to its surface tension adjustment feature [9] .
A total of 38 different recipes were used in different groups as Tetra Pak (TP), TP + plastic (PE), Tetra Pak + plastic (PE) + matching chemical/filler. In the laboratory environment, in a press (hot) at 200 bar pressure, at 170°C for approximately 10 minutes. It was pressed and produced in 1 × 30 × 30 cm dimensions. One panel was produced for each recipe. The mixing percentages of the composite panels are shown in Table 1.
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Table 1. Composite panels types and percentages
The differences in the control samples used in the study in terms of various matching chemicals were evaluated by One-way analysis of variance (One-Way Anova test). If there was a statistically significant difference at the P = 0.05 significance level between the composite groups in terms of mechanical properties as a result of the analysis of variance, the Tamhane T2 test, one of the Post-Hoc (Multiple comparison) tests, was used to determine the different composite groups.
3. Results and Discussion
Since the significance level is P < 0.05 in the Anova table, it is seen that there is a statistically significant and significant difference between the groups in terms of the flexural strengths examined. The differences between the mean values of the groups were determined by Tamhane T2 test. It was checked by the Tamhane T2 test which composite groups were different in terms of flexural strength. It is shown in Table 2.
When Table 2 is examined, it has been determined that there is a significant difference between the groups with an asterisk (*) next to them in terms of the
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Table 2. Tamhane T2 test results of flexural strength values of composites.
effect of chemical substance types on the bending strength of composite materials formed with various chemicals and binding agents. According to Tamhane T2 test results, on the modulus of elasticity in bending of Tetra Pak + PE group: Tetra Pak + PE + BA + Titanate, Tetra Pak + PE + Calcite + Titanate, Tetra Pak + PE + SPT + AA + Titanate, Tetra Pak + PE + BA + Mape, Tetra Pak + PE + BA + Silanyl groups determined that showed significant differences. It has been observed that the effect of the type of coupling chemical added to the composites on the flexural strength of Tetra Pak + PE composites generally makes a difference. It was determined that there was no significant difference between the calcite added composite groups and the other groups in terms of flexural strength. It was determined that there was a significant difference between the groups with Boric Acid added to the Tetra Pak + PE mixture with the composite groups with Boric Acid + Titanate and Boric Acid + MAPE added in terms of bending strength. It was determined that there was no significant difference between the flexural strength of the SPT + AA added composite group with the other chemical added composite groups.
Statistical findings of modulus of elasticity (MOE) in bending:
Since the significance level is P<0.05 in the Anova table, it is seen that there is a statistically significant and significant difference in terms of the elasticity modulus examined between the groups. The differences between the mean values of the groups were determined by Tamhane T2 test. It was checked by the Tamhane T2 test which composite groups differed in terms of elasticity modulus.
When Tamhane T2 test results of modulus of elasticity values of composites is examined, it has been determined that there is a significant difference between the groups with an asterisk (*) next to them in terms of the effect of chemical substance types on the modulus of elasticity in bending of composite materials formed with various chemicals and binding agents. According to Tamhane T2 test results, on the flexural modulus of elasticity of Tetra Pak + PE group, Tetra Pak + PE + Calcite, Tetra Pak + PE + Titanate, Tetra Pak + PE + Calcite + Titanate, Tetra Pak + PE + SPT + AA + Titanate, Tetra Pak + PE + SPT + AA + MAPE, Tetra Pak + PE + It was determined that there were significant differences in the BA + Silanyl groups. It has been observed that the effect of the type of coupling chemical added to the composites on the flexural modulus of elasticity of Tetra Pak + Plastic composites generally makes a difference. However, it was determined that Tetra Pak + PE group showed similar modulus of elasticity with Tetra Pak + PE + BA + MAPE and Tetra Pak + Plastic + Calcite + MAPE groups and did not create a significant difference.
4. Conclusions
In the study, silanes, one of the bonding agents or coupling chemicals, are used to match the composite material components to each other. They are the binding agents used to combine polymer and mineral fibers.
According to a study, they reported that EPOLENE E-43, a type of MAPP with low component effects, was successful as a binder in polypropylene PP and thermomechanical pulp composites [10] .
It has been used in our country because of its easy and abundant availability and cheapness. Since Boron production in Türkiye is sufficient for our country, there is no import [11] .
According to a study, the known types of titanate binding agents are very effective in improving the mechanical properties of composites [12] . According to another study, the incorporation of the titanate binding agent resulted in a decrease in yield stress and flexural strength [13] .
Thanks to the covalent bond between the matrix and the fiber obtained by adding silane, swelling of the fibers is prevented [14] . Another binder, maleic agents, which are used to modify the surface, positively affect the interfacial connection and mechanical properties [15] .
The right binding agent creates a water-resistant bond at the interface between inorganic and organic materials. The silane binding agent has a unique chemical and physical property to increase bond strength. Even though the elasticity modules of the composite materials made from waste papers sometimes show very low values with the effect of added plastic material and various chemicals. It can be shown as a good alternative to wood material in terms of both waste evaluation and less deflection by showing high values.
Acknowledgements
This study is based on PhD thesis Composite Materials Production from Waste Paper Products Coated Polymer and was supported by a Scientific Research Project (No 4751-D1-16) Süleyman Demirel University, 2018 (in Turkish).