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The composition–processing–property relationship of imine containing reversible covalent bond containing polymers (RCBPs) was studied using an innovative (regarding this type of polymer) combination of characterization methods. This combination led, for the first time, to a classification of the various chemical reactions occurring during the processing of imine based RCBP, affecting their final chemical structure and properties. RCBPs, based on PIs (polyimines), were synthesized from polyethyleneimine (PEI) and terephthalaldehyde (TPA) in the presence of ethanol. The chemical composition and derived thermal and mechanical properties were investigated. Material characterization using ATR-IR, 13C-solid state NMR, swell tests, and a novel illustrative model based on the Flory–Rehner equation led to the conclusion that at least 80% of the secondary amine groups reacted to form a cross-linking network, along with 100% of the primary amines, and that during 20 min compression molding at 220 °C under 2.7 MPa, a post-curing reaction occurs. 13C-SSNMR and ATR-IR indicated that the chemical structure is determined not only by the reactants but also by the elevated temperature processing conditions. During heating, three mechanisms affect the final composition–transimination, reduction (back into amine groups) and oxidation (to oxaziridine and amide groups which are almost negligible). The reduction/oxidation processes were found to dominate the mechanical properties. The vitrification temperature (Tv), which is characteristic of RCBPs, is dependent on the thermal history, with a higher Tv resulting from longer compression molding times. The mechanical properties are affected by the processing temperatures, changing from high-performance to very low strength. Under specific processing conditions, the imine cross-linking bonds are reduced/oxidized, which causes the formation of more polar but lower energy bond cross-linking, resulting in lower tensile strength and a change in the hydrophobicity of the polymer, which may be used in future applications.

Antiviral polymers are part of a major campaign led by the scientific community in recent years. Facing this most demanding of campaigns, two main approaches have been undertaken by scientists. First, the classic approach involves the development of relatively small molecules having antiviral properties to serve as drugs. The other approach involves searching for polymers with antiviral properties to be used as prescription medications or viral spread prevention measures. This second approach took two distinct directions. The first, using polymers as antiviral drug-delivery systems, taking advantage of their biodegradable properties. The second, using polymers with antiviral properties for on-contact virus elimination, which will be the focus of this review. Anti-viral polymers are obtained by either the addition of small antiviral molecules (such as metal ions) to obtain ion-containing polymers with antiviral properties or the use of polymers composed of an organic backbone and electrically charged moieties like polyanions, such as carboxylate containing polymers, or polycations such as quaternary ammonium containing polymers. Other approaches include moieties hybridized by sulphates, carboxylic acids, or amines and/or combining repeating units with a similar chemical structure to common antiviral drugs. Furthermore, elevated temperatures appear to increase the anti-viral effect of ions and other functional moieties.

The development of efficient synthetic strategies for incorporating antibacterial coatings into textiles for pharma and medical applications is of great interest. This paper describes the preparation of functional nonwoven fabrics coated with polyaniline (PANI) via in situ polymerization of aniline in aqueous solution. The effect of three different monomer concentrations on the level of polyaniline coating on the fibers comprising the fabrics, and its electrical resistivities and antibacterial attributes, were studied. Experimental results indicated that weight gains of 0.7 and 3.0 mg/cm2 of PANI were achieved. These levels of coatings led to the reduction of both volume and surface resistivities by several orders of magnitude for PANI-coated polyester-viscose fabrics, i.e., from 108 to 105 (&Omega, /cm) and from 109 to 105 &Omega, /square, respectively. Fourier Transform Infrared (FTIR) Spectroscopy and Scanning Electron Microscopy (SEM) confirmed the incorporation of PANI coating with an average thickness of 0.4&ndash, 1.5 &micro, m, while Thermogravimetric Analysis (TGA) demonstrated the preservation of the thermal stability of the pristine fabrics. The unique molecular structure of PANI, consisting of quaternary ammonium ions under acidic conditions, yielded an antibacterial effect in the modified fabrics. The results revealed that all types of PANI-coated fabrics totally killed S. aureus bacteria, while PANI-coated viscose fabrics also demonstrated 100% elimination of S. epidermidis bacteria. In addition, PANI-coated, PET-viscose and PET fabrics showed 2.5 log and 5.5 log reductions against S. epidermidis, respectively.