No abstract

The effects of alkali treatment and dune sand (DS) addition on the mechanical, morphological, thermal and water absorption behavior of date palm fiber (DPF) reinforced unsaturated polyester (UP) composites were investigated. The composites were synthesized by hand lay-up method with 10, 20, and 30 wt% of both treated and untreated date palm fiber (TDPF/DPF). Furthermore, composites having 10, 20 and 30 wt% of untreated date palm fiber and dune sand (both of them were in equal wt%) were also fabricated. Alkali treatment improved the tensile strength, tensile modulus, flexural strength and flexural modulus of the resulting composites. Scanning electron microscopy (SEM) revealed the better interfacial interaction of treated date palm fibers/UP composites. Thermogravimetric analysis (TGA) showed that thermal stability, and degradation temperature of treated DPF composites were best over the untreated DPF composites. Water absorption test indicated the decreasing of hydrophilic character of the filler after treatment with sodium hydroxide (NaOH). Overall analysis represented that satisfactorily improved physical properties of UP for various engineered and hi-tech applications were obtained with 10 wt% fillers loading (5 wt% date palm fiber and 5 wt% dune sand particles).

This article investigates the mechanical, morphological, and thermal properties of poly(vinyl chloride) (PVC) and low‐density polyethylene (LDPE) blends, at three different concentrations: 20, 50, and 80 wt% of LDPE. Besides, composite samples that were prepared from PVC/LDPE blend reinforced with different date palm leaf fiber (DPLF) content, 10, 20, and 30 wt%, were also studied. The sample in which PVC/LDPE (20 wt%/80 wt%) had the greatest tensile strength, elongation at break, and modulus. The good thermal stability of this sample can be seen that T10% and T20% occurred at higher temperatures compared to others blends. DPLF slightly improved the tensile strength of the polymer blend matrix at 10 wt% (C10). The modulus of the composites increased significantly with increasing filler content. Ageing conditions at 80°C for 168 h slightly improved the mechanical properties of composites. Scanning electron microscopic micrographs showed that morphological properties of tensile fracture surface are in accordance with the tensile properties of these blends and composites. Thermogravimetric analysis and derivative thermogravimetry show that the thermal degradation of PVC/LDPE (20 wt%/80 wt%) blend and PVC/LDPE/DPLF (10 and 30 wt%) composites took place in two steps: in the first step, the blend was more stable than the composites. In the second step, the composites showed a slightly better stability than the PVC/LDPE (20 wt%/80 wt%) blend. Based on the above investigation, these new green composites (PVC/LDPE/DPLF) can be used in several applications. J. VINYL ADDIT. TECHNOL., 25:E88–E93, 2019. © 2018 Society of Plastics Engineers

In this contribution, two mononuclear molybdenum complexes with H 2 L tridentate (ONO) Schiff base ligand are characterized using computational techniques. Density functional theory (DFT) and its time extension (TD-DFT) calculations are performed to study the electronic structure in ground and excited state and to interpret the electronic absorption spectra in gas and aqueous phases. TDDFT calculations affirm that the LMCT charge transfer dominates for both complexes and a hypochromic effect on absorption properties is observed according to solvent substitution. All theoretical results compare nicely with available experimental data.