Bioactive Propolis-Silane System as Antifungal Agent in Lignocellulosic-Polymer Composites.

Polymer composites with renewable lignocellulosic fillers, despite their many advantages, are susceptible to biodegradation, which is a major limitation in terms of external applications. The work uses an innovative hybrid propolis-silane modifier in order to simultaneously increase the resistance to fungal attack, as well as to ensure good interfacial adhesion of the filler-polymer matrix. Polypropylene composites with 30% pine wood content were obtained by extrusion and pressing. The samples were exposed to the fungi: white-rot fungus Coriolus versicolor, brown-rot fungus Coniophora puteana, and soft-rot fungus Chaetomium globosum for 8 weeks. Additionally, biological tests of samples that had been previously exposed to UV radiation were carried out, which allowed the determination of the influence of both factors on the surface destruction of composite materials. The X-ray diffraction, attenuated total reflectance-Fourier transform infrared spectroscopy, and mycological studies showed a significant effect of the modification of the lignocellulose filler with propolis on increasing the resistance to fungi. Such composites were characterized by no changes in the supermolecular structure and slight changes in the intensity of the bands characteristic of polysaccharides and lignin. In the case of systems containing pine wood that had not been modified with propolis, significant changes in the crystalline structure of polymer composites were noted, indicating the progress of decay processes. Moreover, the modification of the propolis-silane hybrid system wood resulted in the inhibition of photo- and biodegradation of WPC materials, as evidenced only by a slight deterioration in selected strength parameters. The applied innovative modifying system can therefore act as both an effective and ecological UV stabilizer, as well as an antifungal agent.

Recent developments in microbial degradation of polypropylene: Integrated approaches towards a sustainable environment.

Fossil-fuel-based plastics have many enticing properties, but their production has resulted in significant environmental issues that require immediate attention. Despite the fact that these polymers are manmade, some bacteria can degrade and metabolise them, suggesting that biotechnologies based on the principle of plastic biodegradation could be beneficial. Among different types of plastics, polypropylene (PP), either having low or high density, is one of the most consumed plastics (18.85%). Their debasement under natural conditions is somewhat tricky. Still, their debasement under natural conditions is rather difficult slightly. However, different scientists have still made efforts by employing other microbes such as bacteria, fungi, and guts bacteria of larvae of insects to bio-deteriorate the PP plastic. Pre-irradiation techniques (ultraviolet and gamma irradiations), compatibilizers, and bio-additives (natural fibers, starch, and polylactic acid) have been found to impact percent bio-deterioration of different PP derivatives stronglythe various. The fungal and bacterial study showed that PP macro/microplastic might serve as an energy source and sole carbon during bio-degradation. Generally, gravimetric method or physical characterization techniques such as FTIR, XRD, SEM, etc., are utilized to affirm the bio-degradation of PP plastics-based materials. However, these techniques are not enough to warrant the bio-deterioration of PP. In this regard, a new technique approach that measures the amount of carbon dioxide emitted during bacterial or fungus degradation has also been discussed. In addition, further exploration is needed on novel isolates from plastisphere environments, sub-atomic strategies to describe plastic-debasing microorganisms and improve enzymatic action strategies, and omics-based innovations to speed up plastic waste bio-deterioration.

The Impact of Filler Geometry on Polylactic Acid-Based Sustainable Polymer Composites.

Recently, biocomposites have emerged as materials of great interest to the scientists and industry around the globe. Among various polymers, polylactic acid (PLA) is a popular matrix material with high potential for advanced applications. Various particulate materials and nanoparticles have been used as the filler in PLA based matrix. One of the extensively studied filler is cellulose. However, cellulose fibres, due to their hydrophilic nature, are difficult to blend with a hydrophobic polymer matrix. This leads to agglomeration and creates voids, reducing the mechanical strength of the resulting composite. Moreover, the role of the various forms of pure cellulose and its particle shape factors has not been analyzed in most of the current literature. Therefore, in this work, materials of various shapes and shape factors were selected as fillers for the production of polymer composites using Polylactic acid as a matrix to fill this knowledge gap. In particular, pure cellulose fibres (three types with different elongation coefficient) and two mineral nanocomponents: precipitated calcium carbonate and montmorillonite were used. The composites were prepared by a melt blending process using two different levels of fillers: 5% and 30%. Then, the analysis of their thermomechanical and physico-chemical properties was carried out. The obtained results were presented graphically and discussed in terms of their shape and degree of filling.

Biopolymers for Biomedical and Pharmaceutical Applications: Recent Advances and Overview of Alginate Electrospinning.

Innovative solutions using biopolymer-based materials made of several constituents seems to be particularly attractive for packaging in biomedical and pharmaceutical applications. In this direction, some progress has been made in extending use of the electrospinning process towards fiber formation based on biopolymers and organic compounds for the preparation of novel packaging materials. Electrospinning can be used to create nanofiber mats characterized by high purity of the material, which can be used to create active and modern biomedical and pharmaceutical packaging. Intelligent medical and biomedical packaging with the use of polymers is a broadly and rapidly growing field of interest for industries and academia. Among various polymers, alginate has found many applications in the food sector, biomedicine, and packaging. For example, in drug delivery systems, a mesh made of nanofibres produced by the electrospinning method is highly desired. Electrospinning for biomedicine is based on the use of biopolymers and natural substances, along with the combination of drugs (such as naproxen, sulfikoxazol) and essential oils with antibacterial properties (such as tocopherol, eugenol). This is a striking method due to the ability of producing nanoscale materials and structures of exceptional quality, allowing the substances to be encapsulated and the drugs/ biologically active substances placed on polymer nanofibers. So, in this article we briefly summarize the recent advances on electrospinning of biopolymers with particular emphasis on usage of Alginate for biomedical and pharmaceutical applications.