New Waste-Based Composite Material for Construction Applications

The global demand for fiber-based products is continuously increasing. The increased consumption and fast fashion current in the global clothing market generate a significant quantity of pre-and post-production waste that ends up in landfills and incinerators. The present study aims to obtain a new waste-based composite material panel for construction applications with improved mechanical properties that can replace traditional wood-based oriented strand boards (OSB). The new composite material is formed by using textile wastes as a reinforcement structure and a combination of bi-oriented polypropylene films (BOPP) waste, polypropylene non-woven materials (TNT) waste and virgin polypropylene fibers (PP) as a matrix. The mechanical properties of waste-based composite materials are modeled using the Taguchi method based on orthogonal arrays to maximize the composite characteristics’ mechanical properties. Experimental data validated the theoretical results obtained.

Influence of Printing Substrate on Quality of Line and Text Reproduction in Flexography

This study characterizes and compares the parameters of the quality reproduction of fine elements in flexography on coated and uncoated paper as well as on OPP film (oriented polypropylene). A monochrome test form was created and printed using cyan UV ink. The analysis of results confirms the importance of interaction between the printing substrate and ink; it also indicates identical line and text deformations on the print. Quality reproduction on coated paper is higher in relation to OPP film for all the research parameters. The ink penetrates significantly more and with more irregularity into the pores and throats of the uncoated paper, which results in less homogeneous elements, and in such way that it loses its original shape. In coated paper and OPP film, the ink spreads more on the substrate area which gives it a significantly more homogeneous shape. However, due to the surface spread of the ink, the biggest changes in the size of fine elements are noticeable in the OPP film. The scientific contribution of this paper is based on the comparison of print quality parameters of fine elements, which can contribute to the optimization of the production process and quality of the final graphical product.

New composite materials using polyester woven fabric scraps as reinforcement and thermoplastic matrix

In this study, polypropylene-based thermoformed composites have been obtained using polyester woven fabric scraps as reinforcement. Four types of matrix have been used for the experiments: biaxially oriented polypropylene bag waste (BOPP), polypropylene nonwoven waste (TNT), 50/50 BOPP/TNT waste and virgin polypropylene fibres (PP). The percentage of matrix has been varied at four levels: 20%, 30%, 40%, and 50%. The effect of matrix/reinforcement mass ratio and matrix type on the mechanical properties of composite materials has been studied. Since the composite materials are intended to replace the oriented strand boards (OSB) in construction and furniture applications, comparison with the characteristics of 8 mm OSB has been made.

Effect of Polymerizable Emulsifiers on the Properties of Polyacrylate Latexes and the Relative Waterborne Inks

Polyacrylate latexes made from non-polymerizable emulsifiers and their inks typically suffer from poor ethanol resistance stability and low adhesion on biaxially oriented polypropylene (BOPP) and polyethylene (PE) films. In this contribution, a composite emulsifier system containing a polymerizable anionic and a polymerizable non-ionic emulsifier was used to synthesize core-shell polyacrylate latexes. Additionally, a control latex was also prepared using a traditional emulsifier TX-30 to replace the polymerizable non-ionice mulsifier in the above composite emulsifiers. The effect of the polymerizable emulsifier on ethanol resistance, Ca 2+ resistance stability, and adhesion on PE and BOPP films of the latexes and the inks, and water resistance of the latex films and ink films were studied. The results show that, when compared with the control latex, the one made from double polymerizable compound emulsifier system and its ink demonstrates better ethanol resistance, higher stability of calcium ions and higher adhesion on BOPP and PE. When the ratio of anionic emulsifier to non-ionic emulsifier is 1.5/1 and the total dosage is 2.5 wt%, the latex showed the best comprehensive performance. The calcium ion resistance stability of the latex increased from 5% of the control latex to 25%. Accordingly, the adhesion of yellow ink on BOPP film increased from 92% of the ink based on the control latex to 99% and increased from 99% to 100% on PE film. The adhesion of blue ink on BOPP film increased from 92% to 99%, and from 99% to 100% on PE film. These results indicate that the fully polymerizable emulsifiers can effectively improve the properties of latex.

Plastic drawing response in the biaxially oriented polypropylene (BOPP) process: polymer structure and film casting effects

Processing isotactic polypropylene (iPP) from cast film into biaxially oriented polypropylene (BOPP) involves plastic drawing of a semi-crystalline morphology in the melting range of iPP, where the crystal phase is reduced and the polymer has high mobility. The literature claims that plastic drawing in general and at elevated temperatures in particular depends predominantly on the structure of the amorphous entanglement network. We investigated this aspect using laboratory-scale biaxial drawing experiments. Three iPP homopolymer types differing in chain isotacticity and molecular weight distribution were extruded into 200-μm-thick primary sheets using 10 different extrusion settings. The sheets were biaxially drawn on a laboratory stretcher at 157°C and 160°C, recording the respective stress-strain curves. These curves were evaluated according to a rubber elasticity model to obtain the network modulus, GN, of the entanglement network. The effects of iPP type, the extrusion parameters, the resulting cast film properties, and the draw temperature on GN are discussed.

Application of complex radiation and refrigeration technology for antiseptic treatment and preservation of the quality of mushrooms

The use of effective physical processing methods to preserve food and agricultural products is gaining more and more popularity every year. This article presents a complex technology, including processing by accelerated electrons with doses of 1–3 kGy at a beam energy of 5 MeV. The efficiency of application of processing with accelerated electrons and modification of the composition of the gaseous medium for optimization of the technology of refrigerated storage of champignon mushrooms has been investigated. The technology parameters have been established to ensure microbiological safety and preservation of the consumer qualities of mushrooms under production conditions. The treatment with accelerated electrons at doses of 1–3 kGy in combination with cooling and modification of the composition of the gaseous medium delayed the postharvest maturation processes and led to an increase in the storage time of mushrooms up to 20 days (control 10–14 days). The modification of the composition of the gaseous medium was ensured by the selective gas permeability of the used packaging material (polypropylene, polyethylene, biaxially oriented polypropylene) and the respiration of the raw material. Depending on the intended purpose of the product - fresh sale or further processing (drying, freezing, etc.), the technology under consideration, due to the differentiated choice of technological parameters of storage and processing, allows to control changes in organoleptic, physicochemical and microbiological indicators of the quality of mushrooms in a targeted manner. Packaging made of biaxially oriented polypropylene and polypropylene should be used for mushrooms for processing, due to the best preservation of the structure of plant tissue, as a result of slowing down the ripening processes and delaying aging and spoilage, for the sale of fresh mushrooms, it is most effective to use polyethylene packaging.

Development of Approaches for Producing Polymeric Composite Materials with Higher Strength

In laboratory conditions, oriented polypropylene composite materials containing various concentrations of anisotropic carbon nanoparticles (nanofibers, nanotubes) were obtained. The change in the mechanical properties of oriented composites is determined. Based on structural studies, it was shown that the increase in strength in oriented composites is associated with the formation of a more perfect supramolecular structure of the polymer matrix due to the introduction of low concentrations of nanofillers.