Search

The nanocomposites of high-density polyethylene, low-density polyethylene, polypropylene, and poly(vinyl chloride) reinforced with Azadirachta indica wood flour (WF) and different amounts of the organomodified nanoclay and titanium dioxide (TiO2) nanopowder were produced by melt-blending process followed by compression molding. Polyethylene- co -glycidyl methacrylate (PE- co -GMA) was used as a compatibilizer. TiO2 nanopowder was synthesized by sol–gel method and characterized using transmission electron microscopy (TEM). The average size of the synthesized nano-TiO2 was 17.5 nm, which was confirmed both by TEM and X-ray diffraction (XRD) study. The distribution of nanoparticles in the nanocomposites was also examined by the XRD study. The surface modification of the TiO2 nanoparticles by organic surfactant cetyl trimethyl ammonium bromide and their interaction with the wood and the polymer were studied by Fourier transform infrared spectroscopy. Incorporation of compatibilizer PE- co -GMA, nanoclay, and nano-TiO2 significantly influenced the mechanical and thermal properties of the WF-reinforced composites. Wood polymer composites (WPC) reinforced with nanoclay and nano-TiO2 showed improved tensile strength, tensile modulus, flexural strength, flexural modulus, and hardness. Maximum improvement in mechanical properties was shown by WPC loaded with 40 phr WF, 2 phr nanoclay, and 2 phr of nano-TiO2. On inclusion of organically modified nanoclay and nano-TiO2, the WPC samples showed lower water uptake and higher chemical resistance. The nanocomposites were further examined by TEM study and thermogravimetric analyzer. [ABSTRACT FROM AUTHOR]

Enhanced atmospheric pressure corona-based weakly ionized plasma was investigated to modify surface properties of wood materials. The plasma was generated using a point-to-point bare electrode geometry without dielectric barriers. The gas-phase admixture used in this work was argon and acetylene. Wood fibers were processed in the post-discharge region outside of the harsh corona environment. Return corona emanating into the high-voltage gap from the grounded screen was utilized to effectively activate acetylene molecules near the substrate. Scanning electron microscopy was used to study the surface morphology of the treated and untreated substrates. The treated wood material was observed to contain on their surface nano- and micro-nodules of plasma-polymerized acetylene. Capillary rise measurements confirmed changes in the surface wettability of the substrates. The water capillary rise rate and diffusion coefficient were reduced by about 37% and 57%, respectively, for a 15-min treatment of ponderosa pine wood flour. [ABSTRACT FROM AUTHOR]

This work addressed questions regarding the fate of wood pulp fibers in the composite manufacturing process, for instance whether the processing induced fiber damages, and the improved interfacial adhesion accelerated this function. A number of wood fibers were blended with various maleic anhydride-grafted polymers fully and partially to study their morphological changes. The fractured fibers were separated from wood composites with aromatic hydrocarbons and analyzed using Fiber quality analyses, Scanning electron microscope, Fourier transform infrared analysis and X-ray photoelectron spectroscopy to validate the degree of fiber fractures and the esterification reaction. The fiber damages were related to the maleic anhydride grafting degree, molecular weight and molecular structures of maleated polymers. [ABSTRACT FROM AUTHOR]

A systematic study of effects of concentrations of maleated polypropylene (MAPP), dicumyl peroxide (DCP), Nanoblend concentrate (MB1001) and birch fibers on the mechanical properties of birch-polypropylene (PP) composite was undertaken with the objective to protect or increase the impact strength without losing tensile strength. Using Stagraphic Plus, the Central Composite Design made it possible to determine the optimum concentrations of additives and to maximize both the impact as well as tensile properties to reach values well above that of virgin PP. [ABSTRACT FROM AUTHOR]

Systemic studies of the effects of the concentrations of maleated polyethylene (MAPE) loading, the content and addition sequence of dicumyl peroxide, the content and type of nanoclay (NC), and aspen fiber loading on the mechanical properties of PE-aspen composites were undertaken with the objective to increase the impact strength as well as the tensile properties. In this article, the formation of an optimal compatibilizing system for the hybrid composite PE-aspen-NC by combining basic principles for compatibilization was investigated. Statistical approach experimentation using Statgraphics Centurion® with the objective to maximize both the tensile strength as well as the impact properties of natural fiber and nanoclay filled PE was applied to reach values well above that of virgin PE. [ABSTRACT FROM AUTHOR]

Wood plastic composite with high modulus and impact strength were manufactured by combining polyethylene (PE) or polypropylene (PP) with wood fiber (WF) using twin-screw extruder techniques. The advantage of using low melt viscosity polymer matrices is that it enhances the modulus and reduces the overall viscosity of the system. SEM analysis of the composites indicates that tlie polynler molecules penetrate into the vessels and cracks of tlie cellulose fiber, which decreases the number of voids and produces a higher density composite with improved mechanical performance. The addition of maleic anhydride-grafted polyolefin as a compatibilizer improves the level of adhesion between the wood fiber and the polyolefin matrix. The impact strength of the conlposites with compatibilizer is 60%higher than those without. Young's moduli of WF/PE and WF/PP with compatibilizer were 4.4 and 5.4GPa, respectively, nieanwhile the impact strengths of WF/PE and WF/PP were 44 and 24J/ni, where the WF content was 50wt%. [ABSTRACT FROM AUTHOR]

Studies on the effect of blending method, the introduction method of initiator (dicumyl peroxide, DCP), and the blending time with antioxidant (Irganox) added on the mechanical properties of PP-Aspen composites with and without DCP, respectively are undertaken. An optimum blending time for the composite with Irganox is obtained. The optimum content of Irganox as well as pre-mixing and the final-step feeding-method of DCP are compared to that of conventional method of blending in order to achieve the optimum values of impact and tensile strength properties. [ABSTRACT FROM AUTHOR]