No abstract

No abstract

The purpose of this study is to investigate the direct effect of using a blowing agent of siloxane (1, 1, 3, 3-tetramethydisiloxane) on the thermo-physical properties of the foamed epoxy. These properties are: density, glass-transition temperature, thermal conductivity and thermal expansion. The work has been conducted experimentally by manufacturing several specimens with different siloxane contents as: 0, 5, 10, 15 and 20 wt%. The properties of the specimens have tested under suitable conditions using different reliable instruments: differential scanning calorimetry, Lee-discs apparatus, and push rod dilatometer. Scanning electron microscope was used as well to analysis the morphological characteristics of the epoxy with respect to the pores generated by the blowing agent. In general, the foamed epoxy has shown different sizes of pores and extra crosslinking which leads to increase the glass-transition temperature of the material. Results show that the addition of 20% siloxane to the neat epoxy (as maximum) leads to: decreasing by 50% in bulk density, increasing by 20% in glass-transition temperature, decreasing by 30% in thermal conductivity, and decreasing by 75% in thermal expansion.

This study aims to study the compressive strength and ultrasonic pulse velocity of mortar which contains epoxy composed of two parts: resin and hardener, .at 5, 10, 15, and 20 (wt. %) of epoxy content at different ages (7, 28) days. Where the results showed an increase in the value of compressive strength gradually and the highest at 15% of epoxy content (64.6, and 69.4 MPa) at (7, 28) day, respectively.

Introduction of polymers into the cement composites improves same of the properties of concretes and mortars. Therefore, the polymer-cement composites are successfully used in construction. The model of microstructure formation in cement composites modified with thermoplastic polymer (pre-mix modifiers) has already been developed and successfully implemented. However, the formation of microstructure in the case of epoxy-cement composites (containing post-mix modifier) demonstrates same peculiarities which should be taken into account when modelling the process. The microstructure of epoxy-cement composites and its formation is discussed in the paper. The model is offered, formulated on the basis of the microscopic observations and results of testing.