Stringent environmental regulations and increased interest in the preservation of natural resources have forced the composite industry to examine “ecofriendly” components. Efforts are being deployed to find alternative reinforcements and resin systems that are environmentally friendly while providing the same performance as their synthetic counterparts. The aim of this article is to study the potential of using date palm fibers (DPF) as reinforcement in polymeric materials. This objective was achieved by characterizing the DPF through the evaluation of their chemical, physical, and mechanical properties and comparing them with other commonly used natural fibers. The effect of different surface modification processes on DPF properties such as tensile strength, density, surface morphology, and thermal stability were investigated. POLYM. COMPOS., 26:486–497, 2005. © 2005 Society of Plastics Engineers.

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Due to increased awareness on the part of end users and pressure from legislators, the composite industry has begun investigating the possibility of increasing the proportion of recycled or biodegradable composite materials. Accordingly, efforts are being deployed to find alternative reinforcement and resin systems that are environmentally friendly while providing the same performance as their synthetic counterparts. Natural fibers offer the potential to act as a reinforcing material for low to medium strength applications. In this study a natural fiber extracted from the date palm tree was used as reinforcement for polymeric matrix composites. Polyester composite specimens reinforced with date palm fibers (DPF) were subjected to various types of mechanical and physical tests in order to assess their performance. Results show that these fibers may yield reasonable properties and could be used for low-cost applications that require low to medium strength. Tests indicate, however, that additional work is needed to enhance the compatibility between the fiber and the matrix. POLYM. COMPOS., 26:604 -613, 2005.

This study reports on waterborne polymer emulsion systems that were used for structural modification of sandy soils. The first emulsion used was a styrene-acrylic, copolymer emulsion; the second and third were vinyl-acrylic, copolymer-based emulsions. Specimens were prepared by adding different polymer emulsions to the sand and water in prescribed amounts. The performance of the different emulsion systems as sand stabilizers was estimated through measurement of the hydraulic conductivity and compressive strength. Measurements of hydraulic conductivity were conducted in a flexible membrane test apparatus. The hydraulic conductivity for the three emulsions decreased at different rates, with an increase in polymer content up to 3 wt. (i.e., % by weight). Additional increase of polymer content did not introduce significant decrease in hydraulic conductivity, and, at 5 wt.%, the three emulsions had essentially the same effect. Measurements made on dry cylindrical specimens disclosed remarkable enhancement in the mechanical behavior of the system. The compressive strength and modulus of elasticity of the examined emulsions increased with a higher concentration of polymer. Scanning electron microscope (SEM) revealed that the reduction in the permeability and the improved mechanical properties can be attributed to three dominant structural changes: the development of interconnecting ties between the sand particles, the development of adhesion between neighboring sand particles in contact, and the covering of the sand particles with a thin polymer film.

A new approach is described for utilizing the swelling characteristics of montmorillonite (MMT) to compensate for polymerization-induced shrinkage in unsaturated polyester. The naturally sorbed sodium cation, at the lamellar interface of the mineral, was exchanged with the onium salt of 12-aminolauric acid to produce organophilic MMT, which was compatible with the host resin. The latter, boosted by a small amount of dimethylformamide, swelled into a polymerizing polyester resin, thus reducing polymerization shrinkage. The incorporation of 5% 12-aminolauric MMT caused the shrinkage of the neat isophthalic polyester resin to be reduced from 8.7 to 2.6%. Wide-angle X-ray diffraction and high resolution scanning electron microscopy analyses showed that the shrinkage reduction was associated with increased interparticle spacing and uniform dispersion of the MMT domains on the nanoscale. Mechanical measurements indicated that the flexural strength of the new compound was comparable to that of the neat resin; however, a remarkable 100% increase in toughness was observed in association with a minor decrease in the modulus of elasticity. This increased toughness may be attributed to macromolecular changes associated with the monofunctional acid moiety of the 12-aminolauric acid. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: [767][768][769][770][771][772][773] 2005