Recently discovered SARS-CoV-2 caused a pandemic that triggered researchers worldwide to focus their research on all aspects of this new peril to humanity. However, in the absence of specific therapeutic intervention, some preventive strategies and supportive treatment minimize the viral transmission as studied by some factors such as basic reproduction number, case fatality rate, and incubation period in the epidemiology of viral diseases. This review briefly discusses coronaviruses' life cycle of SARS-CoV-2 in a human host cell and preventive strategies at some selected source of infection. The antiviral activities of synthetic and natural polymers such as chitosan, hydrophobically modified chitosan, galactosylated chitosan, amine-based dendrimers, cyclodextrin, carrageenans, polyethyleneimine, nanoparticles are highlighted in this article. Mechanism of virus inhibition, detection and diagnosis are also presented. It also suggests that polymeric materials and nanoparticles can be effective as potential inhibitors and immunization against coronaviruses which would further develop new technologies in the field of polymer and nanoscience.

This study details about the synthesis of micro-crystalline cellulose prepared from olive pits, the waste material obtained in olive industry, and the effect of these fillers on the tensile and thermal properties of polyvinyl alcohol/starch blends. Micro-crystalline cellulose from olive pits was prepared, and its size was measured using particle size analyzer. Composites were prepared for various micro-crystalline cellulose loading (0, 1, 3, and 5 wt.%) by solution casting method for the blend ratio of 70/30, respectively. Glycerol (3.78 g) was used as plasticizer in all formulations. Universal testing machine, thermogravimetric analyzer, differential scanning calorimeter, X-ray diffractometer, and scanning electron microscopy were used to study the tensile, thermal, and surface morphology of these bio-composites. Results indicated an increase in the tensile properties especially the Young's modulus from 100 to 180 MPa for composites having 1 wt.% of micro-crystalline cellulose and the same formulation showed higher thermal stability.

Date palm ( Phoenix dactylifera L) is one of the most widely cultivated crops in different parts of Saudi Arabia. The midribs rich in cellulose, hemicellulose, and lignin are often burnt in the farms, causes severe environmental problems. In the present study, date palm midrib (DPM), these waste materials were powdered and incorporated into polyvinyl alcohol (PVA). Composites were prepared by varying the DPM loading (0–10 wt%) using the solution casting method. Tensile and thermal properties were analyzed for the composites with respect to filler loading. Addition of DPM as filler enhanced the tensile modulus while an inverse effect was observed in the elongation values. Differential scanning calorimeter (DSC) analysis showed a gradual increase in melting temperature (Tm) and crystallinity values for PVA. Thermogravimetric analysis (TGA) indicated that the incorporation of DPM into PVA can increase the thermal stability of PVA. Morphology of the composites were performed using scanning electron microscopy (SEM).

In this study, a biocompatible and non-toxic pH-responsive composite film was prepared for food packaging application. The films are composed from polyvinyl alcohol as the main polymeric matrix, nanoclay as a reinforcing component and red cabbage extract as a non-toxic indicator. The prepared films showed lower water uptake values when the amount of nanoclay was increase up to 25 %. It was observed that the films become brittle at high loading of nanoclay (40%). The prepared films exhibited color change in alkaline and acidic medium due to the presence of red cabbage extract which turned pinkish in acidic medium and greenish in alkaline environment. The prepared films were characterized by FTIR and visible spectroscopy. The maximum absorption in acidic medium was (λmax = 527 nm), while a red-shift occurred in the alkaline medium (λmax = 614 nm). Future work will focus on crosslinking of the prepared films to improve their mechanical properties.