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DFT molecular modeling studies were undertaken to shed light on possible activation and deactivation mechanisms of Ziegler-Natta catalytic systems, as well as on the possible mechanisms for their reactivation by organohalides. We focused our efforts on Ti species attached to the (110) lateral cut of MgCl 2 . First, the possible activation of adsorbed TiCl 4 leading to an adsorbed Ti III species bearing a Ti-alkyl bond and a coordination vacancy, which is a species able to undergo chain-growth, was considered. According to our calculations formation of the first active species can be easily rationalized by cleavage of a Ti-Cl bond of coordinated TiCl 4 by AlEt 3 , followed by transalkylation promoted by another AlEt 3 molecule. Second, we investigated the possible reduction of polymerization active Ti III species leading to polymerization inactive Ti II species, and we found that a Ti-H bond, possibly formed after chain termination, is weaker than the Ti-Et (polymeryl) bond. Third, we investigated the mechanism of reactivation of Ti II species by organohalides, and it was concluded that reoxidation by Cl rich organohalides is thermodynamically more favored.

Preparation of polyurethanes derived from novel 1,2,3triazole-functionalized soybean oil-based polyols and assessment of their possible biocidal activities were considered. Epoxidized soybean oil was reacted with sodium azide to produce an azide-containing polyol. The product was subjected to the cycloaddition reaction with various alkynes. Alkylation of tertiary amine-containing polyol with methyl iodide was also performed to prepare a quaternary ammonium salt (QAS)-containing polyol. The polyols and their mixtures with PEG1000 were reacted with isophorone diisocyanate to prepare polyurethane coatings. The influence of embedded functional groups on physical, mechanical, thermal and biological properties of polyurethanes was studied. Incorporation of 1,2,3-triazole groups within the polyol backbone resulted in higher storage modulus at glassy state, glass transition temperature, thermal stability and hardness of corresponding polyurethanes, while it led to lower adhesion strength and hydrophilicity. Although QAS-containing polyurethanes displayed better physical and mechanical properties, but their thermal stability were reduced. Studying the interaction of fibroblast cells with polyurethanes derived merely from oil-based polyols revealed their good cells viability (60− 110%). Moderate to high biocidal activity was detected for polyols and polyurethanes containing tertiary amine and QAS groups. Improving the hydrophilicity of polyurethanes via incorporation of PEG1000 improved their biocidal activity, while it reduced their cytocompatibility.

Preparation of antibacterial polyurethane coatings from novel functional soybean oil was considered in this work. First, epoxidized soybean oil (ESBO) as a low price and widely available renewable resource raw material was subjected to the reaction with aniline using an ionic liquid as a green catalyst. The intermediate phenylamine containing polyol (SAP) was then methylated by reaction with methyl iodide to produce a polyol (QAP) with pendant dimethylphenylammonium iodide groups. To regulate the physical and mechanical properties as well as biological characteristics of final coatings, QAP was mixed with different portions of a similar soybean oil-based polyol (MSP) without quaternary ammonium groups. The mixtures were reacted with isophorone diisocyanate to produce crosslinked polyurethane coatings. Evaluation of viscoelastic properties by DMA method revealed single phase structure with Tg in the range of 50-82°C. Stress-strain analysis of the prepared polyurethanes showed initial modulus, tensile strength, and elongation at break in the ranges of 13-299 MPa, 4.5-13.8 MPa, and 16-109%, respectively. Additionally, the coatings showed good adherence to aluminum and PVC substrates. The solvent extracted samples showed excellent biocompatibility as determined by monitoring L929 fibroblast cells morphology and MTT assay. Meanwhile, very promising antibacterial properties against both Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria with bacterial reduction in the range of 83-100% was observed.

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