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Agricultural lignocellulosic fiber (wood flour)-waste was used to prepare composite materials through partial replacement of wood flour with low density polyethylene powder (LDPE) ranged from 10 to 20% by weight; these composites were made with and without electron beam irradiation (EB). The results obtained showed that, flexural strength, modulus of elasticity, modulus of rupture, and impact strength increase with increasing content of LDPE up to 20%. While, the percentages of thickness swelling and water absorption are decreased directly with increasing content of LDPE. Furthermore, the EB irradiation improves the physico-mechanical properties of composite materials from 10 to 50 kGy. The results obtained are also confirmed by scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). POLYM. COMPOS.,

Composite materials are widely used in aeronautical, marine and automotive industries, because of their excellent mechanical properties, low density and ease of manufacture .However, composite laminates are susceptible to delaminations, which may not be visible externally, but can substantially affect the performance of the structure. Vibration testing, in particular delamination detection, in the composite structures is an active research area. ' D Alembert principle is used to determine the theoretical natural frequency of laminated orthotropic composite plate. The present free vibration experimental study of simply supported square laminated plates is based on the comparison between natural frequencies of healthy and delaminated composite plates. The test square plates made of hand lay up 8 layers E-glass woven fibre and epoxy resin are used here. The present paper discusses the observations made on the measured natural frequencies of vibration testing from both the healthy and the delaminated square simply supported plates. The possibility of the delamination detection by vibration testing is also introduced. The effects of delamination area on the natural frequencies of the plate are presented. The delamination in composite laminates has considerable effect on the natural frequencies of the plate.

This study focuses on the partial substitution effect of ordinary Portland cement (OPC) by different ratios of waste glass powder (5%, 10%, and 20% by weight of cement) on the performance of blended cement mortars. The hardened blended cement mortars were first cured under tap water for different time intervals 3, 7, 28, and 90 days. However, the effect of addition of 10% styrene‐acrylic ester as well as the influence of different doses of gamma rays on the physico‐chemical and mechanical properties of polymer modified blended cement mortar specimens were discussed. Compressive strength, total porosity, and water absorption percentages were measured. The experimental results showed that the physico‐chemical and mechanical properties of blended cement mortars specimens improved as the waste glass content increases up to 20%. In addition, irradiated SAE blended cement mortar composites containing 20% waste glass showed an enhancement in its properties as compared to neat cement (0%WG content) composites. The results were confirmed by X‐ray diffraction, thermogravimetric analysis, and scanning electron microscopy. POLYM. COMPOS., 39:985–996, 2018. © 2016 Society of Plastics Engineers