1. 1. To identify a series of Schiff-base compounds from chitosan by condensation with various aldehydes with different electronic and steric characters to give C=N (imine-based) derivatives of chitosan wherein the structural & functional properties can be systematically varied.
   2. To develop quaternary composite systems by synthesizing chitosan-based Schiff bases of polyvinyl alcohol (PVA), polyacrylic acid (PAA), corn cob ash (CCA) and silver naitrate (AgNO₃) using ultra sonication assisted solution blending for the preparation of multifunctional composites that could be combined as polymer additives to cementitious materials.

   3- To characterize the synthesized Schiff base compounds and their quaternary composite systems using FT-IR, ¹H-NMR, XRD, TGA and SEM analyses to identify chemical structure, crystallinity and thermal stability as well as surface morphology.

   4- To use the prepared quaternary composite systems as functional additives directly in cement mortar and concrete production at different dosage levels and evaluate their effects on the mechanical properties — compressive strength flexural strength, tensile strength at normal curing ages of 7, and 28 days as per standards.

   5- To explore the effect of the composite additives on physical and durability-related properties of modified cement mortar, i.e. bulk density, water absorption and porosity, also to study microstructure characteristics of hardened specimens by SEM and XRD to clarify interaction mechanisms between the composite additives and cement hydration products.

   6- To ascertain the optimal dosage concentration and the most efficacious chitosan-derived Schiff base composite system, as well as to delineate the structure-property correlations that influence the efficacy of these composite additives within the cementitious matrix, thereby illustrating their promise as sustainable, biopolymer-sourced, multifunctional modifiers for cement mortar and concrete.

This study, which was conducted at the University of Baghdad / College of Science for Women / Department of Chemistry and Wassit Construction Lab September 2025 to March 2026. The mechanical and physical properties of cement mortar were examined using compressive strength analyzwe and Vicat  apparatus.

1. To gain a more comprehensive understanding of the long-term service performance of the developed composite systems, the durability testing of the composite-modified cement mortar was extended to include 90-day and 180-day durability testing, as well as testing in aggressive environmental conditions (sulfate attack, chloride penetration, freeze-thaw cycling).
2. Expansion of the class of heterocyclic amine precursors used for the synthesis of Schiff bases such as pyridines, imidazoles, benzimidazole, thiazole and pyrimidine derivatives with potential additional donor sites and biological activity profiles not examined in the present study, and further enrich the structure-property database developed herein.
3. Increasing the number of aldehyde types used in both synthetic axes; chitosan-based and heterocyclic amine-based, and investigating the potential for introducing crosslinked Schiff base networks with improved thermal stability and interfacial bonding to the cementitious matrix using polyfunctional and bifunctional aldehyde types.
4. Performing a thorough TE-LCA of proposed quaternary composite additive systems to determine the scalability, cost-effectiveness and environmental impact of the proposed additive system compared to the existing synthetic polymer modifiers used in cementitious construction materials.
5. Research the antimicrobial effectiveness of the hybrid nanocomposites containing silver when added to cementitious materials, especially those for which the materials have increased biological resistance.
6. Investigate other renewable agricultural waste materials, which can be used as sustainable reinforcing fillers for cement composites, apart from corn cob ash, to enhance environmental sustainability.
7. Study the compatibility of the synthesized Schiff base derivatives with various biopolymers and synthetic polymers for further development of new multifunctional hybrid nanocomposites with improved thermal, mechanical and physicochemical properties. Evaluate the performance of the developed hybrid nanocomposites in other cement composite materials like concrete, lightweight concrete, self-compacting concrete, and geopolymer composites.