Synthesis and Characterization of Novel PEPPSI type Pd–BICAAC Complexes

A series of bicyclic alkylamino carbenes (BICAAC) (where N-aryl = dipp, mes, 2,6-dimethyl-4-(dimethylamino)phenyl, 5a-d) and their novel air- and moisture-resistant pyridine (pyridine, 4 dimethylaminopyridine) containing palladium PEPPSI-type Pd(II) complexes (6a-e) were synthetized and characterized. The new palladium complexes have shown high activity in Mizoroki–Heck coupling reaction even at as low as 100 ppm loading (TON up to 10000). Kinetic studies revealed that reactions carried out in the presence of elemental mercury resulted in decrease in activity. It indicates that the coupling reaction may have both molecular and Pd(0)-mediated catalytic paths.

SAFETY OF PAPER PACKAGING MATERIALS WITH POLYMER COATINGS

Background. Packaging materials that are intended for contact with food are subject to the strictest requirements for their safety. When choosing packaging material for such products, first of all it is necessary to ensure the required level of sanitary and hygienic characteristics. The aim of the study is to assess the safety of moisture-resistant waterproof and moisture-resistant and water-resistant waterproof PPM (paper packaging materials) with a polymer coating. Materials and methods.The object of the study is PPM, made by processing the base paper with coatings based on PVA (polyvinyl alcohol) and PAAEX (polyamidamine-pichlorohydrin). The safety of the developed packaging materials was assessed by organoleptic and physicochemical methods for the presence of foreign tastes and odors, the level of migration of vinyl acetate and epichlorohydrin, the content of zinc, lead, cadmium and microbiological indicators by standard methods. Results. Packaging paper must meet the requirements of current regulations in terms of quality, and its use is allowed subject to compliance with state sanitary norms. Studies of organoleptic characteristics of extracts of paper packaging materials did not reveal the presence of foreign tastes and odors. Determination of the amount of migration of harmful substances, namely vinyl acetate and epichlorohydrin, showed that the transition of the components of the solutions, which are impregnated with paper materials is within acceptable limits. The content of zinc and lead was 25 and 3 times less than the maximum allowed by regulations. The microbiological parameters of the developed paper packaging materials meet the regulatory requirements and allow their use for food packaging. Conclusion. Developed new types of paper packaging materials on the level of migration of toxic compounds (vinyl acetate, epichlorohydrin), heavy metal content and microbiological indicators meet the requirements for packaging both food and non-food products of pharmaceutical, medical, cosmetic and other industries.

Recycling of Plastics from Cable Waste from Automotive Industry in Poland as an Approach to the Circular Economy

This paper presents the contemporary problems of polymer waste recycling, mainly recycling cables from end-of-life vehicles. The authors developed a new material based on mixed polymer waste (ASR) modified with a ductile polymer, mainly recycled low-density polyethylene (rLDPE), to produce moisture-resistant boards with beneficial mechanical properties. The ASR-based compositions without and with homogenization process—including physical, chemical, and shear-assisted compatibilization—were successfully applied and verified by evaluating final recycled product properties. The results showed that recycled polyethylene (rLDPE) was effective as a modifier increasing tensile modulus and flexural strength compare to an ASR mixture. It was found that the adding 5 wt % of polyethylene-grafted maleic anhydride (PE-g-MAH) as a compatibilizer to the ASR mixture significantly increases the homogenization of the components in the ASR matrix. The optimal solution for management cable waste is the manufacture of ASR composites with homogenization using an internal mixer the adding 20 wt % of rLDPE and 5 wt % of PE-g-MAH to the mixed plastics cable waste. The results obtained demonstrate that the hot-pressing with the pre-blending with rLDPE and compatibilizer of the ASR based waste provides a high gain in mechanical and usage properties, enabling the circular economy of plastics from automotive cables.

PAPER PACKAGING MATERIALS: RESISTANCE TO DESTRUCTIVE FACTORS

Background. The dynamics of change of the complex of barrier and strength properties of moisture-resistant waterproof and moisture-resistant grease-proof paper packaging materials under the influence of temperature, humidity and mechanical factors is considered. The results of tests of the developed samples of paper packaging materials during exposure in the chamber of heat and moisture aging are given. Materials and methods. Paper packaging materials of grades B-55 and ZhV-55 were obtained by surface treatment with compositions using polyamide­amine­pichlorohydrin, polyvinyl alcohol, urea and glycerin.To test for heat resis­tance and moisture resistance, the PPM samples were placed in a temperature-humidity aging chamber and kept for 900 days at a given temperature (–18, –1, +6, +18, + 25 °C) and relative humidity (45, 65, 85 %), periodically (every 180 days) determining the change in their mechanical strength and barrier properties. The resis­tance of barrier properties to the effects of repetitive mechanical loads was determined by measuring the corresponding index at the site of multiple double bends. Results. During 360 days of exposure, the test samples practically do not lose resistance to the penetration of water (B-55) and fat (ZhV-55). After this exposure period, there is an intensification of degradation processes, which is more pronounced at temperatures below 0 °C. The maximum decrease (32 %) of fat permeability was recorded at a temperature of –18 °C after 900 days of ex­posure, while at temperatures above 0 °C, at this exposure, it is not more than 4 %. The strength of the packaging paper at temperatures of –1 °C and –18 °C during the test period in waterproof materials decreased by 6 % and 12 %, and in grea­seproof – 19 % and 29 %, respectively. The higher loss of strength of fat-impermeable PPM is due to the nature of the main component of the hydro­oleophobic composition – PVA, which has a higher brittleness temperature com­pared to PAAEX in the hydrophobic composition. After 150 cycles of alternating freezing and defrosting of the samples, the destructive force of the greaseproof material ZhV-55 is reduced to 57.5 N, and the waterproof B-55 – to 63 N. The destructive force for 30 repeated cycles of tem­perature change is 70.9 N and 67.3 N, in comparison with the initial values of 72.4 and 71.8 N for waterproof (B-55) and greaseproof (ZhV-55) wrapping paper, respectively. With 50 repeated double bends, which is close to the real conditions of use of packaging paper for its intended purpose, the water permeability of the sample B-55 is reduced by 8 %, and the fat permeability of the sample ZhV-55 – by 3 %. Conclusion. The established dependences allow us to state that the main factors determining the barrier and strength properties of the developed materials are: physicochemical nature of the main components of hydrophobic and hydro­oleophobic compositions, which determines the nature of their interaction with cellulose fiber; resistance of the structure of the material to the penetration of moisture and fat, as well as its ability to withstand various mechanical loads.