Determining the mechanical properties of epoxy resin (DGEBA) composites by ultrasonic velocity measurement

Abstract

In this study, the composites of diglycidyl ether of bisphenol A (DGEBA) epoxy resin that have been formed by mixing epoxy resin with allyl glycidyl ether (AGE) and 2,3-epoxypropyl methacrylate [glycidyl methacrylate (GMA)] were prepared in weight % ratios of 90 : 10, 80 : 20, and 70 : 30. A computer controlled analyzer with 35 MHz and a digital oscilloscope with 60 MHz were used for measuring the velocities of ultrasonic wave. The measurement of ultrasonic velocity carried out by pulse echo method at frequencies of 2.25 and 3.5 MHz at room temperature. The values of acoustic impedance (Z), Poisson ratio (l), and coefficients of elasticity (L, G, K, E) of composites were calculated by values of densities and velocities that obtained. Thus, the effect of modificating epoxy resin (DGEBA) by AGE and GMA on mechanical properties of DGEBA was investigated using the ultrasonic method. Atomic force microscopy has been used for determining the microstructure of composites. By the results obtained from the investigation, it have been established that the longitudinal and shear ultrasonic wave velocities, and the values of all the elasticity constants of DGEBA were increased by modification with AGE and GMA. Also the most suitable combination ratio for the compound of DGEBA : AGE and DGEBA : GMA has been found as 80 : 20.

Effect of ultrasonic and sonic activation of root canal sealers on the push‐out bond strength and interfacial adaptation to root canal dentine

“…, Oral et al . , Lionetto & Maffezzoli ). Lower bond strength was observed in the apical and middle thirds because the coronal root third has a greater number of tubules, tubular diameter and amount of intertubular dentine (Mjör et al .…”

“…MTA Fillapex has low bond strength to dentine because the interfacial layer with the cross-link structures of this sealer provides poorer adhesion to dentinal tubules (Sagsen et al 2011). MTA Fillapex had lower bond strength to dentine than AH Plus, possibly because the smaller amount of resin matrix in its composition (Amoroso-Silva et al 2014) did not allow for an effective action of the ultrasound (Bittmann et al 2009, Oral et al 2012, Lionetto & Maffezzoli 2013. Lower bond strength was observed in the apical and middle thirds because the coronal root third has a greater number of tubules, tubular diameter and amount of intertubular dentine (Mj€ or et al 2001), favouring the adhesion of sealers to dentine walls and to the collagen structure (Neelakantan et al 2011, Carneiro et al 2012.…”

Ultrasonic characterization of conductive epoxy resin/polyaniline composites

“…32 The composite containing 5 wt % percolation concentration of PANI is at the semiconductive level. The conductivity of ER is rised up to 15 wt % PANI concentration and changes in the range of 7.04 3 10 24 23.02 3 10 23 S cm 21 . It is clear that the conductiviy of pure ER is about 10 214 (S cm 21 ), which shows that conductivity of pure ER is at the nonconductive level.…”

“…One of the way to form new conductive polymer with better mechanical properties is to prepare epoxy/PANI composites by mixing PANI with ER. Because of their increasing engineering applications, ER and ER‐based composites are extensively studied in recent year . However, no investigation of the elastic properties of ER/PANI composites by ultrasonic velocity measurement has been reported.…”

“…Because of their increasing engineering applications, ER and ER-based composites are extensively studied in recent year. [18][19][20][21][22][23] However, no investigation of the elastic properties of ER/PANI composites by ultrasonic velocity measurement has been reported. Many studies are carried out to increase the conductivity and mechanical properties of PANI-based composites.…”