%0 Journal Article
%T New Polymeric Admixture for Cement Based on Hyperbranched Poly Amide-Ester with Pentaerythritol Core
%A Amal Amin Ibrahim
%A Ahmed El-Sayed Abdel-Megied
%A Mohamed Sayed Selim
%A Hassan Hassenen Darweesh
%A Magdy Mohamed Ayoub
%J ISRN Materials Science
%D 2013
%R 10.1155/2013/270987
%X Hyperbranched poly amide-ester (HBPAE) was synthesized by a solution condensation polymerization through one-step process using pentaerythritol as a central core and AB2 prepolymerized monomer which was rapidly prepared at room temperature (25¡ãC) using commercially available maleic anhydride (MA) and diethanolamine (DEA) monomers in the presence of p-toluene sulfonic acid as a catalyst. The prepared polymer was characterized by GPC, IR, 1H-NMR, and thermal analysis (TGA and DSC). The influence of the polymer addition to the cement paste was investigated by measuring the effect of 1, 3 and 5 wt% HBPAE solutions on the properties of ordinary portland cement (OPC). Accordingly, several parameters were investigated such as water of consistency, setting times, bulk density, apparent porosity, compressive strength, and combined water content of the polymer/cement pastes. The SEM images proved that the incorporation of HBPAE with the OPC cement did not affect the chemical composition of hydrates, but it only affected the physical state, shape, size, morphology, and crystallinity of the formed hydrates. The results showed that the polymer addition to OPC pastes improved the physicomechanical properties of cement. 1. Introduction In the recent years, significant efforts have been focused on synthesis and application of the hyperbranched polymers as they exhibit many special merits such as highly branched three-dimensional globular architecture, low viscosity, high solubility, abundance of functional end groups, and internal cavities in the molecule, which can be easily designed to meet specific needs in various applications [1¨C3]. Hyperbranched polymers can be easily prepared in one-step reactions and typically have randomly distributed branches that make them attractive alternatives for numerous applications in comparison with their regular counterparts (dendrimers) which need more expensive and drastic conditions to be properly prepared [4¨C6]. Hyperbranched polymers are potentially applied in various fields from drug delivery to coatings where increasing scientific interest for them over the past several decades is evident and confirmed by the increasing number of publications [7¨C12]. The concept of the polymer modification for the cement mortars and concretes is not new, since a considerable research and development of a polymer modification have been performed for the past decades [13, 14]. Consequently, various polymer-based admixtures have been developed to produce the currently popular construction materials because of their good cost-performance balance
%U http://www.hindawi.com/journals/isrn.materials.science/2013/270987/