Synthesis of poly (Methyl methacrylate) reinforced by multi-walled carbon nanotubes and magnetite nanofillers

Abstract

Polymer technologies are shown as one of the most important achievements in science and engineering in our recent history. Polymers have a wide variety of material groups according to their chemical and physical structures, from synthetic form plastic to natural form DNA and proteins. One of them is poly (methyl methacrylate) (PMMA), known as acrylic, which has a thermoplastic and amorphous structure. PMMA is a lightweight and easily shaped material, and thanks to this feature, widely used in industrial fields. In addition, the transparent structure of PMMA exhibits low transmittance, and therefore optical properties can be compared with glass. With the hardness and scratch-resistance of the material and relatively low cost, PMMA replaces glass and vitreous products in industrial use. PMMA is a polymer type preferred in construction applications due to resistance to extreme weather conditions. With the reinforcements to be applied in the structure of PMMA, there is a strong possibility to obtain unique properties by attempting various polymerization methods. Manufacturing PMMA nanocomposites indicates extraordinary properties by obtaining an accurate and homogeneous distribution to the polymer matrix. Carbon nanotubes (CNT), which are widely used among nanomaterials, are used in polymer-derived materials as reinforcement factors. Carbon nanotubes are the name given to the cylindrical structure formed by the circular folding of the graphene layer. Depending on the folding state, two types of carbon nanotubes are formed as single-walled (SWCNT) or multi-walled (MWCNT). The nanocomposite structure formed by PMMA and MWCNT has thermal stability, thermal resistance, high strength, hardness, etc. The polymer-nano coupling contains an extraordinary increase in mechanical and thermal properties, which implicates many important qualities, can be used in industries for space, defense, satellite, aviation, etc. Another group of nanoparticles that is used in many industrial fields defines as magnetite nanoparticles, which are called ferrite (Fe3O4), cobalt ferrite (CoFe2O4), and their metallic oxides (Co3O4). The nanocomposites strengthened with these nanoparticles greatly contribute to the homogeneous dispersion and aggregation degree, the interaction force between the particles, and the surface magnetism. This study aims to contribute to industrial areas such as aerospace, aviation, and satellite technologies, improving the mechanical and thermal properties of PMMA polymer by strengthening the PMMA polymer with MWCNT nanoparticles and reinforcing with magnetite nanoparticles simultaneously. Additionally, to discuss the effect of magnetite nanoparticles reinforced on nanoparticles, inorganic cobalt sulfate heptahydrate (CoH14O11S) crystal was reinforced with PMMA polymer reinforced with MWCNT. Atomic Transfer Radical Polymerization (ATRP) was selected as the polymerization method in this study. ATRP is a widely preferred method in controlled-living radical polymerization applications because of the easy-to-access and low-cost reagents and is easily applicable in the laboratory environment. Advantages of this method; are controlled and rapid growth in polymer chains, functionality at the macromolecular level, and containing both the activate and deactivate mechanism of the catalytic system. Additionally, the experimental conditions can be optimized as desired. However, it is more difficult than expected to reach the optimum conditions in this method with many component groups. Since ATRP is an air-sensitive method, it is important to work in a mechanism that prevents oxygen uptake to prevent the formation of unwanted radicals. To prevent these unfavorable conditions and not impact the quality of the produced nanocomposites, the experimental setup operates in the Argon gas environment. PMMA/Nanofiller nanocomposites and PMMA composites were successfully produced using the ATRP method. For characterization analysis, Scanning Electron Microscope (SEM), Fourier Transformation Infrared Spectroscopy (FT-IR), X-Ray Diffraction (XRD), Thermogravimetric Analysis (TGA), Raman Spectroscopy, X-Ray Photoelectron Spectroscopy (XPS), Ultrasonic Test, many distinct applications such as Static Contact Measurement analysis, and Rockwell M Hardness Test have been carried out. In the SEM analysis used for the surface morphology, when PMMA/MWCNT, PMMA/Magnetite, and PMMA/CoH14O11S/MWCNT nanocomposites are examined, the homogeneous distribution on the surface of all samples draws attention. Although no aggregation or clumping of the nanoparticles was observed, in fact, the nanoparticles showed a fairly regular distribution in the polymer lattice, thus affecting the mechanical properties. In XRD characterization were analyzed changes in the crystal structure. According to this test result, characteristic diffraction values of PMMA and nanoparticles were obtained. FT-IR and Raman Spectroscopy results indicate that the interaction of PMMA and nanoparticles successfully satisfied the characteristic spectra of homogeneous and particular peaks. XPS analysis results also indicate that the increase in carbon and oxygen element was observed as the mass percent of the nanocomposite increased. At the same time, the presence of characteristic elements was confirmed by test outcomes. Ultrasonic test analysis was carried out to investigate the mechanical properties. Concepts such as elastic modulus, shear modulus, and microhardness were calculated using transverse and longitudinal wave velocities and with the help of various equations. According to the calculations, 4% wt. of PMMA/MWCNT nanocomposite display an increment to shear modulus of ~54%, the microhardness of ~53%, and an elastic modulus of ~59%. Furthermore, ~48% shear modulus, ~46% microhardness, and ~49% elastic modulus increment were observed for 3% wt. of PMMA/Co3O4/MWCNT nanocomposite. As a result of TGA measurements, 4% wt of PMMA/MWCNT nanocomposite improved the temperature at which it experienced 5% mass loss compared to pure PMMA with an increase of ~48°C. In addition, 3% wt of PMMA/CoFe2O4/MWCNT nanocomposite improved the temperature at which it experienced 5% mass loss compared to pure PMMA with an increase of ~39°C.