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

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

A study of mechanical properties and performance of bamboo fiber/polymer composites

In recent years, bamboo seems to have attracted the attention of researchers due to its advantages over synthetic polymers including being renewable, environmentally friendly, and fully biodegradable. Bamboo fibers at (9, 13, and 18 wt%) are filled with epoxy resin and the effects of mixing the bamboo fibers on mechanical properties were studied. In this paper, the tensile properties and performance of natural bamboo fiber powder-reinforced epoxy polymer matrix-based composites were investigated at three different curing temperatures ranging from T26 °C, T38 °C, and T50 °C. The results showed that the tensile strength and Young's modulus of the bamboo fiber/epoxy composites increased at T26 °C are 41.6 MPa and 2.84 GPa, respectively, for particle size 0.52 μm at a weight loading of 13 %. The increase in tensile strength is due to the excellent fiber matrix interface adhesion. However, it was found that the samples tested under T26 °C for bamboo fiber-reinforced epoxy composites acquired better tensile strength than those tested under the high temperatures of T38 °C and T50 °C. According to the analysis of the flexural characteristics of bamboo particle/epoxy composites, the composite with 1.5 μm particle size has the highest flexural strength at 13 wt% weight loading, measuring 105 MPa. The composite with a 1.5 μm particle size at 18 wt% loading records the maximum impact strength of, 5593 J/m2. This work provides a new approach for the development of lightweight and high-strength composite from natural fiber and polymer

Inhibitive impacts extract of Citrus aurantium leaves of carbon steel in corrosive media

Relatively inexpensive, stable plant extract, namely Citrus aurantium leaves, was employed as highly efficient inhibitor of carbon steel corrosion by corrosive acid. The inhibition efficiency was estimated based on the weight loss method. Inhibition impacts of researched inhibitor increase with the concentration of the plant extract increase. The inhibition efficiency depends on three factors: molecular structure, concentration, and molecular weight of the inhibitor. Inhibition efficiency of 81.2% was achieved with 20% (v/v) of the extract in 1 M hydrochloric acid during 3 h at 25°C. The effect of temperature was also investigated and activation parameters were evaluated. Inhibition adsorption characteristics were approximated by Langmuir adsorption isotherm. Chemical adsorption mechanism was proposed for the studied inhibitor from the trend of inhibition performance and temperature degree in addition to activation energy values and heat of adsorption

Effect of phosphoric acid on the morphology and tensile properties of halloysite-polyurethane composites

The high aspect ratio of nanoscale reinforcements enhances the tensile properties of pure polymer matrix. The composites were first made by adding halloysite nanotubes (HNTs) at low weight percentages of 1, 2, and 3 wt% to thermoplastic polyurethane (TPU). Then, HNTs were phosphoric acid-treated before adding to TPU at same weight percentage to create phosphoric acid HNTs-TPU composites. The samples were fabricated using injection moulding. The HNTs-TPU composites were characterized according to the tensile properties including tensile strength, tensile strain and Young’s modulus. The loading has shown its highest tensile values at 2 wt% HNTs loading and same findings are shown with the samples that treated with phosphoric acid. The tensile strength increased to reach 24.65 MPa compare with the 17.7 MPa of the neat TPU showing about 26% improvement. For the phosphoric acid-treated composites, the improvement has reached 35% compared to the neat sample. Regarding the tensile stain, the improvement was about 83% at 2 wt% HNTs loading. For Young’s modulus, the results obtained in this study have shown that Young’s modulus is linearly improved with either the loading content or the phosphoric acid treated achieving its highest values at 3 wt% HNTs of 14.53 MPa and 16.27 MPa for untreated and treated, respectively. FESEM results showed that HNTs were well dispersed in TPU matrix. Thus, HNTs-TPU has improved tensile properties compared with pure TPU due to the addition of nanofiller. Keywords: Nanotube, Composite, Phosphoric treated, Tensile propert

Absolute variation of the mechanical characteristics of halloysite reinforced polyurethane nanocomposites complemented by Taguchi and ANOVA approaches

The variation of the results of the mechanical properties of halloysite nanotubes (HNTs) reinforced thermoplastic polyurethane (TPU) at different HNTs loadings was implemented as a tool for analysis. The preparation of HNTs-TPU nanocomposites was performed under four controlled parameters of mixing temperature, mixing speed, mixing time, and HNTs loading at three levels each to satisfy Taguchi method orthogonal array L9 aiming to optimize these parameters for the best measurements of tensile strength, Young’s modulus, and tensile strain (known as responses). The maximum variation of the experimental results for each response was determined and analysed based on the optimized results predicted by Taguchi method and ANOVA. It was found that the maximum absolute variations of the three mentioned responses are 69%, 352%, and 126%, respectively. The analysis has shown that the preparation of the optimized tensile strength requires 1 wt.% HNTs loading (excluding 2 wt.% and 3 wt.%), mixing temperature of 190 °C (excluding 200 °C and 210 °C), and mixing speed of 30 rpm (excluding 40 rpm and 50 rpm). In addition, the analysis has determined that the mixing time at 20 min has no effect on the preparation. The mentioned analysis was fortified by ANOVA, images of FESEM, and DSC results. Seemingly, the agglomeration and distribution of HNTs in the nanocomposite play an important role in the process. The outcome of the analysis could be considered as a very important step towards the reliability of Taguchi method. Keywords: Nanocomposite, Design-of-experiment, Taguchi optimization method, Mechanical propertie