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

The world needs an enormous amount of energy to maintain the future economic developments. India has facile ways to overcome the immediate demand on energy supply by renewable energy resources. It has a huge potential of biomass resources to reduce the dependence on fossil fuels and to produce electrical and heat energy. The biomass energy can contributes to social and economic development. It has been identified as an alternative for the future energy demand in India. As part of furthering the development of biomass technology, it is essential to understand the environmental merits and demerits of biomass. It also aims to increase the use of biomass energy for domestic purposes. The interest behind the review is boosted by the rapid development of biomass conversion techniques and continual increase of biomass energy generation. It has motivated the authors to collect the quintessential literature of environmental aspects of biomass energy. The objective of the research work is to quantify and focuses the environmental performance of biomass energy. It also deals with the environment monitoring and control, pricing, standard and regulations of the bio-energy for the future development.

Quantifying environmental performance of biomass energy

A novel approach to property enhancement of poly(l-lactic acid) (PLLA) through the use of perfluoropolyether (PFPE) enchainment is described. Segmented copolymers (FluoroPLA) exhibit tailored surface properties with reasonably high molecular weights and low polydispersities compared to PLLA alone using standard ring-opening polymerization procedures in the presence of tin catalysts. Low loadings of PFPE content (ca. 1−5 wt %) decreases surface energies compared to PLLA from 35 to 38 to 15−18 mN/m2, similar to values reported for poly(tetrafluoroethylene). Ultimate strain studies of FluoroPLA fibers and films have shown a dramatic increase (>300% elongation) over PLLA. This new class of polymer may further expand the use of renewable resources in a variety of applications such as flame retardants, chemical resistant fibers and/or fabrics with tailorable surface energies and wetting properties.

Poly(l-lactic acid) with Segmented Perfluoropolyether Enchainment

Nowadays, utilisation of biodegradable materials has become necessary in order to maintain global environmental and ecological balance. Fully biodegradable nano 'Green' textile composites have been prepared from cellulose nanofibers reinforced corn starch resin and ramie fabric. Nanofibers having dimensions of approximately 1 μm long and 20–30 nm in diameter are used in the study. The nanofibers were incorporated in corn starch resin via ball mill mixing using ceramic balls. Textile composites were fabricated by pasting the reinforced resin onto the ramie fabric and by hot compression molding technique. Interactions at the fiber–matrix interface and the compatibility between cellulose and corn starch resin molecules will affect the properties of the system. The well dispersed cellulose nanofibers contribute higher interfacial area and good fiber networking within the matrix resin. This will lead to better barrier properties. Sorption characteristics of water, oil and diesel in the textile composites were ...

Sorption characteristics of water, oil and diesel in cellulose nanofiber reinforced corn starch resin/ramie fabric composites

The special safeguard mechanism both quantity and price based was key in the July 2008 failure to reach agreement in the World Trade Organization (WTO) negotiations under the doha development agenda. A stochastic simulation model of the world wheat market is used to investigate the effects of the special safeguard mechanism. As expected, the quantity-based safeguard is found to reduce imports, raise domestic prices, and boost mean domestic production in the countries that implement it. However, rather than insulating developing countries in those regions from price volatility, the quantity based safeguard increases domestic price volatility, largely by restricting imports when domestic output is low and prices are high. The quantity based safeguard shrinks average wheat imports nearly 50 percent in some regions, and global wheat trade falls by 4.7 percent. The price-based safeguard discriminates against lower price exporters and contributes to producer price instability.

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E. Douglas Beach

Papers

A note on quality differences and United States/Canadian wheat trade☆

Expanding biodegradable polymer resin use: Assessing the aggregate impact on the US economy