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.

(Quasi)-Binomial vs. Gaussian Models to Evaluate Thiamethoxam, Pirimiphos-Methyl, Alpha-Cypermethrin and Deltamethrin on Different Types of Storage Bag Materials Against Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) and Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae)

The Mediterranean flour moth, Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) and the confused flour beetle, Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae) are worldwide spread and notorious organisms of numerous stored-products. Both species are dangerous for bagged commodities as penetrators and invaders. The aim of the current study was to examine the efficacy of thiamethoxam, pirimiphos-methyl, alpha-cypermethrin, and deltamethrin, against E. kuehniella and T. confusum larvae, on different types of storage bag materials, i.e., woven propylene, biaxially oriented polypropylene and kraft paper through a (quasi)-binomial modeling approach. The type of the tested storage bag material did not affect the mortality rates of both species when treated with the tested insecticides. Thiamethoxam and pirimiphos-methyl showed statistically significant higher mortality rates on E. kuehniella and T. confusum (beta coefficient = 0.141; p-value < 0.05) compared to alpha-cypermethrin and deltamethrin. In addition, T. confusum exhibited significantly higher mortality rate in comparison to E. kuehniella. Our results also showed that the tested doses and surface treatments had a significant effect on the mortality E. kuehniella and T. confusum larvae. Significantly higher mortality rates were recorded when larvae were exposed on bag materials having both surfaces treated or on the single treated surface than when they were exposed on the untreated surface. Our findings can be useful towards an effective management strategy against stored-product insect pests.

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.

Study on the Behavior of BOPP Film Treated by Corona Discharge

Corona discharge is widely used as a good surface pretreatment method for polymer materials. In this work, the attenuated total reflectance Fourier transform infrared spectrometry (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), scanning electronic microscopy (SEM), and atomic force microscopy (AFM) were used to investigate the behavior of biaxially oriented polypropylene (BOPP) film treated by corona discharge. The possibly involved chemical reactions during the corona treatment process under atmosphere components were systematically summarized. This work lays a theoretical basis for improving the performance of BOPP films and expanding their application fields.

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.