Volume 31 (2020): Issue 1 (March 2020)

The amount of used and worn out tires around the world reaches about 10 million tons. Rubber introduction to the environment in this shape is connected with its pollution, caused by tires’ chemical composition, which, apart from synthetic and natural rubber, contain soot as a filler, plasticizers having some amounts of polycyclic aromatic hydrocarbons and helping substances: activators, accelerator of vulcanization, cross-link means and homogenizers. The most important activator is zinc oxide. The aim of the conducted studies was to determine the influence of rubber rag added to the subsoil on the amount of yield, physiological state and the amount of taken zinc by maize (Zea mays). It was found that the rubber rag introduced into the soil caused an increase in the yield of maize and the plants growing on the soil with the highest amount of rubber rag showing higher efficiency photosynthetic apparatus than others. The zinc content in the aboveground parts of maize increased with the increase of rubber rag in the soil.

Lubricants that are based on vegetable oils and other renewable resources are the subject of many research studies and can be used in various applications, especially in the food industry, which is characterized by the high quality requirements related to the necessity to develop biodegradable lubricants that are environmentally friendly and do not contain harmful components and are safe to use for people. The objective of the described research was to obtain a base oil with a certain viscosity, which is higher than the viscosity of the initial vegetable oil, and certain lubricating properties. The initial oil derived from Crambe abyssinica was subjected to oxidation in the presence of N-hydroxyphthalimide with or without supercritical CO₂ as a solvent. As a final result of this study, base oils meeting the viscosity requirements and having high biodegradability were obtained. The Raman spectra of the modified vegetable oils were evaluated and they were used for the initial assessment of the composition and the evaluation of the presence of harmful chemical compounds.

The article presents the results of research on the modification of Epidian 5 epoxy resin by introducing natural modifiers. It's easy accessibility and biodegradability has a positive effect on environmental protection, cost-effectiveness of the process, useful and strength properties of composites. Still looking for the best solutions in the production of epoxy composites combining these features, we have attempted to compare and select the most optimal natural modifier. The epoxy resin was modified with collagen, hemp fibres, cellulose from pepper extraction residues. The amount of amine hardener suggested by the manufacturer was added to the composition. Each composition was cured at room temperature for 24 hours and then cured at 80°C for 3 hours. The prepared composites were subjected to impact assessment additions for mechanical properties, impact strength, three-point bending strength, critical stress intensity factor and gel time.

The paper looks at the ineffectiveness of climate protection undertaken by the United Nations Framework Convention on Climate Change (UNFCCC). Despite the emission reduction measures commenced by some countries, the global emission of carbon dioxide has increased more than 40% since the adoption of the UNFCCC. The most important reason of the catastrophe is the so-called Berlin Mandate (1995), which exempts most of the countries in the world – including China that became the largest emitter in 2006 – from taking any binding commitments to reduce emissions. The Paris Agreement (2015) has been the first attempt to overcome the failure. There are a number of economic reasons why the protection process has not been successful so far. ‘Carbon leakage’ caused by the fact that most countries do not have binding commitments implies that emission from economies that impose restrictions moves to where it is not constrained. This calls for a global agreement on emission reduction. Such a global agreement requires recognition of the fact that climate protection is a public good. It is surprising that those UNFCCC signatories, who are likely to be hit by the lack of protection most acutely, hesitate to adopt effective provisions.