Recent trends in biodegradable polymers indicate significant developments in terms of novel design strategies and engineering to provide advanced polymers with comparably good performance. However, there are several inadequacies in terms of either technology or cost of production especially in the case of applications in environmental pollution. So, there is a need to have a fresh perspective on the design, properties and functions of these polymers with a view to developing strategies for future developments. The paper reviews the present state-of-art on biodegradable polymers and discusses the salient features of the design and properties of biodegradable polymers. Special emphasis is given to the problems and prospects of (1) approaches adopted to make non-biodegradable synthetic polymers such as polyethylene biodegradable and (2) biodegradable polymers and copolymers made from renewable resources especially poly(lactic acid) based polymers and copolymers which are emerging as the candidate biodegradable materials for the future.

Biodegradable Polymers- A Review on Recent Trends and Emerging Perspectives

Due to the depleting fossil fuel sources such as crude oil, natural gas, and coal, the present rate of economic growth is unsustainable. Therefore, many sources of renewable energy have been exploited, but the potentials of some other sources such as plastics waste are yet to be fully developed as full scale economic activity. Development and modernization have brought about a huge increase in the production of all kinds of plastic commodities, which directly or indirectly generate waste due to their wide range of applications coupled with their versatility of types and relatively low cost. The current scenario of the plastic recycling technology is reviewed in this paper. The aim is to provide the reader with an in-depth analysis with respect to the pyrolysis of plastic waste as obtained in the current recycling technology. As the calorific value of the plastics is comparable to that of hydrocarbon fuel, production of fuel from plastic waste would provide a good opportunity to utilize the waste as a better alternative to dumpsites. Different techniques of converting plastics waste into fuel including thermal and catalytic pyrolysis, microwave-assisted pyrolysis and fluid catalytic cracking are discussed in detail. The co-pyrolysis of plastics waste with biomass is also highlighted. Thus, an attempt was made to address the problem of plastic waste disposal as a partial replacement of the depleting fossil fuel with the hope of promoting a sustainable environment.

Current state and future prospects of plastic waste as source of fuel: A review

Lipid oxidation is, together with microbial growth, the main cause of spoilage of a great variety of foods, such as nuts, fish, meats, whole milk powders, sauces and oils. It causes a loss of both sensorial and nutritional quality of foods and may even lead to the formation of toxic aldehydes. Some strategies that are commonly used to limit the extent of lipid oxidation of packaged foods are direct addition of antioxidants or packaging under modified atmospheres in which oxygen presence is limited. A novel alternative to these methods is antioxidant active packaging, whose main advantage is that it can provide sustained release of antioxidants during storage. This article reviews the latest advances in antioxidant active food packaging, with special emphasis on antioxidant release systems. The various methods for incorporating antioxidant compounds in the package, the issues to be considered in packaging design, and the various methods employed to date to evaluate the antioxidant effectiveness of active antioxidant materials are reviewed.

Advances in antioxidant active food packaging

Computers and the collaborative experience of learning

The growing use of plastics in agriculture has enabled farmers to increase their crop production. One major drawback of most polymers used in agriculture is the problem with their disposal, following their useful life-time. Non-degradable polymers, being resistive to degradation (depending on the polymer, additives, conditions etc) tend to accumulate as plastic waste, creating a serious problem of plastic waste management. In cases such plastic waste ends-up in landfills or it is buried in soil, questions are raised about their possible effects on the environment, whether they biodegrade at all, and if they do, what is the rate of (bio?)degradation and what effect the products of (bio?)degradation have on the environment, including the effects of the additives used. Possible degradation of agricultural plastic waste should not result in contamination of the soil and pollution of the environment (including aesthetic pollution or problems with the agricultural products safety). Ideally, a degradable polymer should be fully biodegradable leaving no harmful substances in the environment. Most experts and acceptable standards define a fully biodegradable polymer as a polymer that is completely converted by microorganisms to carbon dioxide, water, mineral and biomass, with no negative environmental impact or ecotoxicity. However, part of the ongoing debate concerns the question of what is an acceptable period of time for the biodegradation to occur and how this is measured. Many polymers that are claimed to be ‘biodegradable’ are in fact ‘bioerodable’, ‘hydrobiodegradable’, ‘photodegradable’, controlled degradable or just partially biodegradable. This review paper attempts to delineate the definition of degradability of polymers used in agriculture. Emphasis is placed on the controversial issues regarding biodegradability of some of these polymers.

https://link.springer.com/content/pdf/10.1007%2Fs10924-007-0063-6.pdf

Biodegradation of Agricultural Plastic Films: A Critical Review

Using the free integrated technologies to provide online collaborative learning at reduced costs

. Thermoluminescent dosimetric features of two batches of fluorite from Romania (Cavnic and Tulcea) are presented. An initial thermal treatment at 600C for 60 min. to cleaning of natural dose has been performed. All samples showed the same glow curve structure with three prominent peaks located at 100, 180 and 280C at a heating rate of 5C/s. An attempt was made to determine the kinetic parameters of TL glow curve. The activation energy E ~ 1.31 eV (Tulcea batch) of the dosimetric peak and the kinetic order b=2 were obtained. The dose response of CaF2:nat from Tulcea to gamma-rays is linear in the range 2 Gy to 5·10Gy, where saturation effects became pronounced. A thermal fading of 18% during 30 days was observed.

https://icstm.ro/DOCS/josa/josa_2010_2/b.02_dosimetric_features_of_natural_fluorite_from_romania.pdf

Dosimetric features of natural fluorite from romania

Analyzing the Relationships between the Teen-agers’ Self-image and their Preferences for Science Disciplines Contents

/pdf/remarks-on-pupils-feedback-concerning-the-implementation-of-3bru8il5ou.pdf

Laura Monica Gorghiu

Papers

Using the free integrated technologies to provide online collaborative learning at reduced costs

Dosimetric features of natural fluorite from romania

Analyzing the Relationships between the Teen-agers’ Self-image and their Preferences for Science Disciplines Contents

Remarks on pupils' feedback concerning the implementation of virtual experiments in Science teaching

Art and Moral Values - A Pedagogical Approach Through the Hexadic Model☆