Effect of alkali and silane surface treatments on the mechanical and physical behaviors of date palm seed-filled thermoplastic polyurethane eco-composites

Abstract

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.

Biodegradable green composite film developed from Moringa Oleifera (Sahajana) seed filler and PVA: Surface functionalization, characterization and barrier properties

“…This is because of salt molecules which lower the action of water molecules and results in accession of salts particles on the surface of sheet which could further obstruct the water uptake. 80 equation 3 that comes out to be 36.85% which is lower than the untreated Coccinia grandis.L (52.17%), 57 untreated Prosopis juliflora (46%) 58 but higher than that of untreated Tridax procumbens (34.46%), 56 untreated Catharanthus roseus (25.09%). 12 The CrI of 2.5% alkali and acid treated are 53% and 66% respectively.…”

“…This is because of salt molecules which lower the action of water molecules and results in accession of salts particles on the surface of sheet which could further obstruct the water uptake. 80…”

Tribological properties of hemp fiber reinforced polylactic acid bio-composites: effect of different types of modification methods

“…Silanization: Hemp fibers were soaked in 2% APTES/ethanol concentration at room temperature for two hours and then several times washed with ethanol. Fibers were dried at 80 • C for four hours [41].…”

Development of turkey feather fiber-filled thermoplastic polyurethane composites: Thermal, mechanical, water-uptake, and morphological characterizations

“…Namely, the natural fibers are mostly the polar and hydrophilic features, whereas the polymeric materials have generally bipolar and also show the considerable hydrophobic properties. 12 Here, it was to be emphasized that the existence of high compatibility and good adhesion between components led the formed composites to exhibit better mechanical performance compared to both partly miscible and immiscible polymer matrices. 13,14 In other words, the formation of relatively stronger and effective intermolecular attraction forces (Van der Waals forces) between the component polymer chains in the matrix provides both the additional endurance and relatively larger withstanding capability against the deformation to the polymeric materials, 15 which results in the reinforcement of the polymer composites.…”