Mechanical and Physical Properties of Injection Molded Halloysite Nanotubes-Thermoplastic Polyurethane Nanocomposites

AbstractThe high aspect ratio of nanoscale reinforcements enhances the mechanical properties of pure polymer matrix. Researchers reported the mechanical properties of thermoplastic polyurethane and halloysite nanotubes (TPU-HNTs) nanocomposites formed through casting and compression molding. Few researchers reported on TPU-HNTs formed through injection molding. Therefore, the present work described the preparation, characterization, and processing of TPU and HNT nanocomposites via injection molding. TPU and HNTs were mixed using a brabender mixer with concentration ranging from 1wt.% to 7wt.% with varying mixing parameters (mixing speed, mixing time, and mixing temperature). Injection molding was used to form tensile bars shaped with varying molding parameters (injection temperature, injection time, and injection pressure). Significant increment of tensile strength was found at 1wt.%HNT loading concentration. The tensile strength of the TPU-HNT nanocomposite exhibited 24.29MPa at 1wt.% loading concentration, which was higher than that of pure TPU. The Young's modulus of the TPU-HNT nanocomposite was 15.45MPa at 7wt.%. Physical properties were analyzed using Thermogravimetric Analysis (TGA) and Field emission scanning electron microscopy (FESEM). FESEM results showed that HNTs were well dispersed in TPU matrix. TGA results showed that the addition of HNTs enhanced the thermal properties. Thus, TPU-HNT has improved mechanical and physical properties compared with pure TPU due to the addition of nanofiller

Effect of HNTs addition in the injection moulded thermoplastic polyurethane matrix on the mechanical and thermal properties

The additions of nanofillers are able to enhance the mechanical properties of neat polymer matrix. There were few researchers reported on the mechanical properties of halloysite nanotubes reinforced thermoplastic polyurethane (HNTs-TPU) nanocomposites formed through casting and compression moulding. However, fewer researchers also reported study on HNTs-TPU formed through injection molding. The main objective of this paper was to study the effect of HNTs addition of TPU matrix on mechanical and physical properties. HNTs were mixed in TPU matrix using a brabender mixer with concentration ranging from 0.5 to 7 wt. % HNT loading (at specific mixing speed, mixing time and mixing temperature). Injection moulding was carried out to form tensile bar shaped specimens with specific moulding parameters (injection temperature, injection time and injection pressure). Increment around 35% of tensile strength of the specimen was found at 1 wt. % HNT loading concentration which exhibited the value of 24.3 MPa, compared to neat TPU; the best mixing. The Young’s modulus was increased with increasing HNTs loading. The elongation decreased with increasing HNTs loading. The FESEM results showed that HNTs were dispersed in TPU matrix. The TGA results showed that the addition of 1 wt. % HNTs enhanced the thermal properties. It can be concluded that HNTs-TPU has improved tensile and physical properties compared with neat TPU due to the addition of nanofiller

Physical properties of halloysite nanotubes-polyvinyl alcohol nanocomposites using malonic acid crosslinked

Halloysite nanotubes (HNTs) based nanocomposites were produced by blending individualized HNTs dispersion with polyvinyl alcohol (PVA). Several sequential separation techniques were applied to obtain stable individualized HNTs dispersion. The preparation of PVA-crosslinked-HNTs nanocomposite has not been developed and, to the best of our knowledge, there was no published report indicating the use of neither dispersion nor crosslinker agent. In addition, PVA was crosslinked using the crosslinker malonic acid (MA) and sulfuric acid as a catalyst. This individualization increases the mechanical and thermal properties of HNTs-PVA nanocomposites. As a side result, crosslinking was employed to make PVA water-insoluble and hence to become more useful in biomedical applications. Examination of the nanocomposites indicated that HNTs were uniformly dispersed in both PVA as well as crosslinked PVA. These nanocomposites could be composted easily and hence would be good candidates to\replace some of today’s traditional non-biodegradable plastics that end up in landfills

Influence of Sulfuric Acid on the Tensile Properties of Halloysite Reinforced Polyurethane Composite / Tayser Sumer Gaaz...[et al.]

In this study, the mechanical properties of injection molded of HNTs-TPU composites were investigated. The composites were first made by adding halloysite nanotubes (HNTs) at weight percentages of 1, 2, and 3 wt.% to thermoplastic polyurethane (TPU). Then, HNTs were sulfuric acid-treated before adding to TPU at same weight percentage to create sulfuric acid HNTs-TPU composites. The samples were fabricated using injection molding. The HNTs-TPU composites were characterized according to the mechanical properties, including tensile strength, tensile strain and Young’s modulus. The highest mechanical values obtained at 2 wt.% HNTs loading, and similar findings are shown at the samples treated with sulfuric acid. The tensile strength increased until reach 23.78 MPa compare with the 17.7 MPa of the neat TPU, which showing about 25% improvement. For the acid-treated composites, the improvement has reached 34.4% compared to the neat sample. Regarding the tensile stain, the improvement was about 82% at 2 wt.% HNTs loading. The Young’s modulus results obtained in this study have shown that it is linearly improved with increment of loading content and sulfuric acid treated of HNTs. Where it achieving the highest values of Young’s modulus at 3 wt.% HNTs of 13.3 MPa and 15.2 MPa for untreated and treated, respectively

Inhibition Effect of Hydrazine-Derived Coumarin on a Mild Steel Surface in Hydrochloric acid

In this work, economy novel hydrazine-derived coumarin 4-(6-methylcoumarin)acetohydrazide (MCA) were synthesized, characterized, and tested as an inhibitor for the corrosion of a surface of mild steel in an acidic environment through weight loss and Scanning electron microscopy (SEM) techniques. Results showed that the synthesized inhibitor can inhibit the corrosion of mild steel surface in a 1 M hydrochloric acid environment. The corrosion inhibition efficiency of MCA increases with increasing MCA concentration and decreases with increasing temperature. SEM analysis showed the formation of a film as a protective layer from MCA molecules on the surface of mild steel. Adsorption of the MCA molecules on the mild steel surface in the presence of hydrochloric acid environment was obeyed Langmuir isotherm. The density functional theory (DFT) calculations were used to study the relationship between molecular structure and inhibition efficiency and they found in good agreement

Evaluation of Green Corrosion Inhibition by Extracts of Citrus aurantium Leaves Against Carbon Steel in 1 M HCl Medium Complemented with Quantum Chemical Assessment

Employing plants as corrosion inhibitors is a physical direction to detect less expensive green friendly inhibitors. Researchers found that the Citrus aurantium leaves extracts are mixtures containing vitamins, minerals, phenolic compounds and terpenoids. The flavonoids contained in C. aurantium can be divided into four groups, including flavones, flavanones, flavonols, and anthocyanins. These compounds indicate the extracts of Citrus aurantium leaves are appropriate to be applied as green corrosion inhibitors. Extracts of Citrus aurantium leaves have been researched by utilizing EIS, gravimetric and SEM techniques as novel eco-friendly corrosion inhibitors for carbon steel in corrosive environments. Inhibition effectiveness of tested extract depends on different concentrations of extract, starting from 0 to 40% v/v. Inhibition effectiveness of 81.2% is reached at the concentration of 20% v/v of the extract in 1 M corrosive solution for three hours at 25℃. Temperature effects and activation parameters have been investigated. A theoretical investigation of Citrus aurantium leaves extract isomers as corrosion inhibitors have been done using DFT/ B3LYP density functional theory. The results shows that, in general, Citrus aurantium leaves have good inhibiting activities at relatively low concentrations. Phenolic groups of Citrus aurantium leaves were picked for examination as substituents of the four inhibitors. Hydroxyl groups of the studied extract compounds result in an increase in inhibition effectiveness, while methylation of the hydroxyl group leads to decrease in inhibitive effectiveness. Citrus aurantium leaves extracted isomers symbolize a considerable enhancement in the inhibition performance

Unique Halloysite Nanotubes–Polyvinyl Alcohol–Polyvinylpyrrolidone Composite Complemented with Physico–Chemical Characterization

A halloysite nanotubes–polyvinyl alcohol–polyvinylpyrrolidone (HNTs–PVA–PVP) composite has been investigated for a quite long time aiming at improving the physico–chemical characterization of HNTs. In this work, HNTs–PVA–PVP composite were prepared based on a unique procedure characterized by crosslinking two polymers with HNTs. The composite of two polymers were modified by treating HNTs with phosphoric acid (H3PO4) and by using malonic acid (MA) as a crosslinker. The composite was also treated by adding the dispersion agent sodium dodecyl sulfate (SDS). The HNTs–PVA–PVP composite shows better characteristics regarding agglomeration when HNTs is treated in advance by H3PO4. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), brunauer–emmett–teller (BET), size distribution, and atomic force microscopy (AFM) are used to characterize the physio-chemical properties of the composite. FTIR shows additional peaks at 2924.29, 1455.7, and 682.4 cm−1 compared to the neat HNTs due to adding MA. Despite that, the XRD spectra do not show a significant difference, the decrease in peak intensity could be attributed to the addition of semi-crystalline PVA and the amorphous PVP. The images taken by TEM and FESEM show the possible effects of MA on the morphology and internal feature of HNTs–PVA–PVP composite treated by MA by showing the deformation of the matrix. The BET surface area increased to 121.1 m2/g compared to the neat HNTs at 59.1 m2/g. This result, the second highest recorded result, is considered a breakthrough in enhancing the properties of HNTs–PVA–PVP composite, and treatment by MA crosslinking may attribute to the size and the number of the pores. The results from these techniques clearly showed that a significant change has occurred for treated HNTs–PVA–PVP composite where MA was added. The characterization of HNTs–PVA–PVP composite with and without treating HNTs and using crosslinker may lead to a better understanding of this new composites as a precursor to possible applications in the dentistry field

Study of the electrical and thermal performances of photovoltaic thermal collector-compound parabolic concentrated

The importance of utilizing the solar energy as a very suitable source among multi-source approaches to replace the conventional energy is on the rise in the last four decades. The invention of the photovoltaic module (PV) could be the corner stone in this process. However, the limited amount of energy obtained from PV was and still the main challenge of full utilization of the solar energy. In this paper, the use of the compound parabolic concentrator (CPC) along with the thermal photovoltaic module (PVT) where the cooling process of the CPC is conducted using a novel technique of water jet impingement has applied experimentally and physically tested. The test includes the effect of water jet impingement on the total power, electrical efficiency, thermal efficiency, and total efficiency on CPC-PVT system. The cooling process at the maximum irradiation by water jet impingement resulted in improving the electrical efficiency by 7%, total output power by 31% and the thermal efficiency by 81%. These results outperform the recent highest results recorded by the most recent work. Keywords: Photovoltaic thermal collectors, Electrical performance, Thermal performance, Compound parabolic concentrator, Jet impingemen

Impact of Sulfuric Acid Treatment of Halloysite on Physico-Chemic Property Modification

Halloysite (HNT) is treated with sulfuric acid and the physico-chemical properties of its morphology, surface activity, physical and chemical properties have been investigated when HNT is exposed to sulfuric acid with treatment periods of 1 h (H1), 3 h (H3), 8 h (H8), and 21 h (H21). The significance of this and similar work lies in the importance of using HNT as a functional material in nanocomposites. The chemical structure was characterized by Fourier transform infrared spectroscopy (FTIR). The spectrum demonstrates that the hydroxyl groups were active for grafting modification using sulfuric acid, promoting a promising potential use for halloysite in ceramic applications as filler for novel clay-polymer nanocomposites. From the X-ray diffraction (XRD) spectrum, it can be seen that the sulfuric acid breaks down the HNT crystal structure and alters it into amorphous silica. In addition, the FESEM images reveal that the sulfuric acid treatment dissolves the AlO6 octahedral layers and induces the disintegration of SiO4 tetrahedral layers, resulting in porous nanorods. The Bruncher-Emmett-Teller (BET) surface area and total pore volume of HNTs showed an increase. The reaction of the acid with both the outer and inner surfaces of the nanotubes causes the AlO6 octahedral layers to dissolve, which leads to the breakdown and collapse of the tetrahedral layers of SiO4. The multi-fold results presented in this paper serve as a guide for further HNT functional treatment for producing new and advanced nanocomposites