Nanocelluloses Reinforced Bio-Waterborne Polyurethane

Fluorescent cellulose nanocrystals/waterborne polyurethane nanocomposites for anti-counterfeiting applications

The development of eco-friendly anti-counterfeiting materials with high optical transparency and bright luminescence in the aggregate state is tremendously challenging. Herein, waterborne polyurethane/tetraphenylethylene-cellulose nanocrystal (WPU/TPE-CNC) nanocomposite aqueous solutions and films were prepared via direct blending aggregation-induced emission (AIE) active fluorescent CNCs (TPE-CNCs) with WPU and then applied in the anti-counterfeiting field. TPE-CNCs are compatible with WPU and dispersed homogeneously in the nanocomposite aqueous solutions and films. The thermal stability and mechanical properties of these films significantly improved with the increase in the content of TPE-CNCs. WPU/TPE-CNC nanocomposite films display high transparency (above 80%), excellent fluorescence properties, high mechanical strength, and good flexibility and then successfully applied to anti-counterfeit marking. Moreover, the dispersions of the aqueous WPU/TPE-CNC nanocomposite were nearly colorless and demonstrated promise as fluorescent anti-counterfeiting inks. This novel eco-friendly nanocomposite exhibited the potential for applications in anti-counterfeiting, fluorescent transparent paper and coating, fluorescent 3D printing, and optical/sensing devices.

Environmental impacts of post-consumer plastic wastes: Treatment technologies towards eco-sustainability and circular economy

The huge amounts of plastic production (millions of tons) are carried out all around world every year and EU is one of the biggest consumers of these products. In 2021, recycling rate of plastic wastes around 32.5% in the EU and the rest end up on their journey in landfills and oceans that lead to environmental pollution which is a crucial global concern. Thus, it is important to take necessary steps to control the use of such plastic and to sustainably dispose them. One of the solutions to the problem is to use a better alternative to plastics which doesn't degrade land, water or air nor affects living organisms. Circular economy is another answer to this problem, it would ensure prevention of post-consumer plastic waste from getting formed. In addition, sustainable disposal approaches for plastic waste such as pyrolysis, plasma gasification, photocatalytic degradation, and production of value-added products from polymer waste can be explored. These recycling methods has huge potential for research and studies and can play a crucial in eliminating post-consumer plastic waste. This review paper aims to discuss the environmental effects of post-consumer plastic wastes as well as the emerging approaches for the treatment of these environmental wastes towards eco-sustainability and circular economy.

Influence of Starch on the Structure–Properties Relationship in Polyethylene Glycol/Polycaprolactone Diol Polyurethanes

Improvements in the antithrombogenicity activity of biomaterials for cardiovascular applications are necessary to meet the demand for vascular grafts in the world. Zwitterionic compounds tend to be used due to their anti-fouling properties, which reduce platelet adhesions and protein absorptions. Therefore, in this research, potato starch (AL-N) and zwitterionic starch (AL-Z) (obtained by Williamson etherification) were included as fillers in polyurethane (PU) matrices from polycaprolactone diol (PCL), polyethylene glycol (PEG), pentaerythritol (PE) and isophorone diisocyanate (IPDI) in order to study their effect in terms of their physicochemical, mechanical and thermal properties. We conducted our evaluation using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), contact angle analysis, swelling behavior, thermogravimetric analysis (TGA), tensile/strain analysis, scanning electron microscopy equipped with energy dispersive X-ray spectroscopy (SEM-EDS), dynamic mechanic analysis (DMA), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). The results showed that AL-N and AL-Z modified these properties, where AL-N improved tensile strength, and AL-Z increased the hydrophilicity of polyurethanes matrices; additionally, AL-N had interactions with the soft segments, and AL-Z had interactions with the hard segments. Finally, both fillers reduced the degree of crystallinity and did not affect the thermal stability of polyurethanes.