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Olive pulp, which is formed 80% in the olive oil extraction process, attracts the attention of researchers with the zero waste project in Turkey. Our study aims to prove that olive pulp is not only a waste and can be used as a resource when used correctly as a filler in composite materials to provide not only durable but also shorter biodegradation times for polymer-based composite materials. The surface modification process with 3 different silanes containing epoxy, vinyl, and amino groups was applied to the surface of olive pulp (OP) to solve the problem of surface incompatibility with eco-grade thermoplastic polyurethane (TPU) matrix. The oil portion of OP was removed before silane treatments. Surface functions and thermal properties of both modified and unmodified OP powder samples were evaluated by FTIR, SEM, and TGA techniques, respectively. TPU/OP composites were fabricated using melt-compounding process, and mechanical, thermomechanical, thermal, melt flow, wear, biodegradation, and morphological properties of composites were reported. According to test results, TPU/VS-OP (vinyl silanized olive pulp) composite showed the highest hardness and wear resistance values among all composites. Additionally, silane modifications led to remarkable improvements for mechanical, thermal, thermomechanical, and melt flow properties of composites thanks to the enhancement of compatibility and interface adhesion between OP and TPU phases. It seems that VS-OP containing composite sample displayed the highest results in most of the examined results. It has been shown that the addition of unmodified and modified OP filler to TPU caused to level of the biodegradation of pure TPU, and as a result, environmentally friendly composites have been produced. [ABSTRACT FROM AUTHOR]

In this study, eco-grade thermoplastic polyurethane (TPU), which includes 46% renewable content, was reinforced with date palm seed (DPS). Alkali and silane surface treatments were applied to DPS to increase the compatibility between DPS and TPU matrix. The oil of DPS was removed before treatments and surface functionalities of modified and pristine DPS samples were examined by Fourier transform infrared spectroscopy. Composites were fabricated using melt blending method and injection molding processes. Test samples of composites were characterized using tensile test, hardness test, water absorption study, dynamic mechanical analysis (DMA), melt flow index (MFI) test, thermogravimetric analysis, and scanning electron microscopy (SEM). According to test results, silane treatment led to remarkable improvement for mechanical performance of composites attributed to improvement of compatibility and interface adhesion between DPS and TPU. DMA results implied that higher storage modulus and glass transition temperature were achieved for treated DPS-containing composites compared to pristine DPS filled ones. Thermal stability of flexible segment of TPU increased with the addition of DPS regardless of surface treatment. Additionally, DPS loadings caused significant increase in MFI value of unfilled TPU. Silane-treated DPS-containing composite yielded the lowest water uptake value among samples due to the hydrophobicity of silane layer. Enrichment of interface adhesion of DPS to TPU matrix was confirmed by SEM micrographs of composites. Silane-treated DPS-containing composite displayed higher results among produced composites since the increase in interfacial interactions with TPU was achieved by silane treatment for DPS surface. [ABSTRACT FROM AUTHOR]

Thermoplastic polyurethane (TPU) composites filled with fullerene in the range from 0.5 wt% to 2 wt% were fabricated using melt-compounding. Fullerene addition levels up to nearly twofold increase in tensile strength, percent elongation, and modulus of TPU. The mechanical properties are improved as modified C60 content decreases. Fullerene loadings also enhance thermal stability of TPU. Glass transition temperature decreases by the inclusion of C60 into TPU matrix. Composites exhibited the improvement for storage modulus and vibration-damping behavior. The UL-94 rating and limiting oxygen index value of TPU are also extended to higher values after C60 loadings. Adjuvant effect is observed on fire performance in which pristine C60 inclusions and higher concentrations of C60 exhibit better fire performance. Additions of C60 give identical melt flow index values with that of TPU. Modified C60 particles disperse more homogeneously than pristine ones into TPU matrix because of the improvement in interfacial interactions between fullerene and polyurethane elastomer. [ABSTRACT FROM AUTHOR]

Alkaline and silane treatments were applied to wood flour (WF) to enrich its adhesion to bio-based thermoplastic polyurethane (TPU) matrix. TPU/WF eco-composites were prepared at a constant ratio of 30% by the melt blending process. The mechanical, thermo-mechanical, melt-flow, water uptake and morphological properties of the materials were investigated. Silane-treated WF filled composite exhibited better mechanical performance with respect to untreated WF due to enhancement of adhesion between WF and TPU matrix after surface treatments. This sample also gave the lowest water absorption value among composites. The results confirmed that silane treatment of WF led to significant improvement on the mechanical and physical properties of TPU-based composites in addition to an improved water resistance for outdoor applications. [ABSTRACT FROM AUTHOR]

Thermoplastic polyurethane (TPU) composites containing carbon nanotube (CNT) with the loading ratios from 0.5wt% to 2 wt% were prepared using melt-compounding process. Surfaces of the CNT particles were treated with sulfuric acid/nitric acid to purify CNT and to achieve compatible surface characteristics between TPU matrix and CNT. Mechanical, thermal, flame retardant, melt flow, and morphological properties of TPU/CNT composites were investigated. Addition of CNT to TPU matrix causes in a prominent increase in tensile strength, percentage of elongation at break, and tensile modulus values of TPU. The mechanical properties are improved for lower modified CNT loadings. CNT inclusions also improve the thermal stability of pristine TPU. Addition of CNT into TPU matrix causes increase in melting and decomposition temperatures of TPU and decrease in glass transition temperature. The flammability parameters of TPU also shift to higher values after CNT loadings to matrix. Modified CNT additions at higher concentrations exhibit better fire performance. Additions of modified CNT and pristine CNT show different trends in the case of melt flow rate values. Modified CNTs disperse more homogeneously relative to pristine ones into TPU matrix which is due to improvement in interfacial interactions between CNT and TPU. [ABSTRACT FROM AUTHOR]

Microwave absorption properties of Epoxy/Nickel Ferrite (NiFe2O4) and Epoxy/Barium Titanate (BaTiO3) composites were investigated and compared in the 1–14 GHz. Epoxy/filler particles (NiFe2O4 and BaTiO3) composites were prepared with 85/15 mixture ratios via Ultrasonic Probe Sonicator method in solution. The complex permittivity (ɛ′‐ ɛ″) and permeability (μ′‐ μ″) of the composites have been measured at different microwave frequencies in 1–14 GHz via vector network analyzer (Keysight N9926A). The reflection loss (RL) of composites was calculated and evaluated from camplex permitivity and permeability. The obtained results show that both composites exhibit the large RL and broadband within the frequency range from 1 to 14 GHz for different thickness. Epoxy/BaTiO3 showed a better microwave absorption at the range of 6–7.2 GHz for 7 and 6 mm, at the range of 7.4–9.1 GHz for 5 mm. However, the Epoxy/NiFe2O4 exhibits the largest RL and the widest bandwidth than those obtained from Epoxy/BaTiO3 composite. POLYM. COMPOS., 39:E2143–E2148, 2018. © 2017 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Acidic pumice (AP) and basic pumice (BP) were compatibilised with the polymer matrix by using silane coupling agents before their addition into polypropylene (PP). In addition, composites with maleic anhydride grafted polypropylene (Ma-g-PP) were prepared. Composites were prepared by melt-blending method using lab-scale twin screw extruder which is the most suitable method for the large scale production. PP composites that obtained as chip form from the mixer were shaped with injection molding. Additionally to the mechanical properties of prepared composites, water absorption test of the composites were performed in order to investigate their outdoor usage conditions. Tensile test, dynamic mechanical analysis (DMA) and melt flow index tests were applied to composites, respectively. Furthermore, scanning electron microscopy (SEM) micrographs were examined for observation of the dispersion of pumice particles into polypropylene matrix. Improvements in mechanical properties of composites were obtained by using silane-modified acidic pumice, basic pumice and MA-g-PP. According to SEM micrographs, composites which contain silanized pumice and MA-g-PP exhibit better dispersion of pumice particles into PP matrix due to compatibilazition of particles with polymer surfaces. There were no remarkable changes observed for the melt flow values of especially acidic pumice containing composites as compared with PP. This results support the conclusion that the addition of pumice caused no obvious problem for the processibily of polypropylene in large scale applications. [ABSTRACT FROM AUTHOR]

Carbon nanotube-reinforced polyurethane elastomer composites were prepared by melt-mixing. Nitric acid oxidation and silanization were applied to carbon nanotube surfaces to achieve better interfacial interactions with polyurethane elastomer. Tensile and hardness tests, differential scanning calorimetry, melt flow index test, dielectric measurements, and morphological studies of composites were reported. The best results were obtained for surface-modified carbon nanotubes containing composites with lower loading levels. Addition of carbon nanotubes leads to almost two-fold increase in strain and modulus compared to pristine polyurethane elastomer. Tensile strength of composites was also improved by inclusion of carbon nanotubes. However, strength values drop down with increasing carbon nanotube content. Shore hardness increased with the inclusion of modified carbon nanotube to polyurethane elastomer while pristine carbon nanotube caused remarkable decrease in hardness of polyurethane elastomer. Relatively higher melting points and slightly lower glass transition temperatures were observed for carbon nanotube-loaded composites compared to polyurethane elastomer because of plasticizing effect of carbon nanotube. Incorparation of carbon nanotube to polyurethane elastomer matrix caused reduction in melt flow index values due to formation of agglomarates, and n the contrary, surface modifications of carbon nanotube exhibited increase in melt flow index thanks to enhanced interfacial interactions between carbon nanotube and polyurethane elastomer. Significant increase in dielectric constant of composites was observed. Better dispersion of surface modified carbon nanotubes into polyurethane elastomer was also concluded from SEM micrographs of composites. [ABSTRACT FROM AUTHOR]