Plastic debris in the marine environment is widely documented, but the quantity of plastic entering the ocean from waste generated on land is unknown. By linking worldwide data on solid waste, population density, and economic status, we estimated the mass of land-based plastic waste entering the ocean. We calculate that 275 million metric tons (MT) of plastic waste was generated in 192 coastal countries in 2010, with 4.8 to 12.7 million MT entering the ocean. Population size and the quality of waste management systems largely determine which countries contribute the greatest mass of uncaptured waste available to become plastic marine debris. Without waste management infrastructure improvements, the cumulative quantity of plastic waste available to enter the ocean from land is predicted to increase by an order of magnitude by 2025.

Packaging waste forms a significant part of municipal solid waste and has caused increasing environmental concerns, resulting in a strengthening of various regulations aimed at reducing the amounts generated. Among other materials, a wide range of oil-based polymers is currently used in packaging applications. These are virtually all non-biodegradable, and some are difficult to recycle or reuse due to being complex composites having varying levels of contamination. Recently, significant progress has been made in the development of biodegradable plastics, largely from renewable natural resources, to produce biodegradable materials with similar functionality to that of oil-based polymers. The expansion in these bio-based materials has several potential benefits for greenhouse gas balances and other environmental impacts over whole life cycles and in the use of renewable, rather than finite resources. It is intended that use of biodegradable materials will contribute to sustainability and reduction in the environmental impact associated with disposal of oil-based polymers.The diversity of biodegradable materials and their varying properties makes it difficult to make simple, generic assessments such as biodegradable products are all 'good' or petrochemical-based products are all 'bad'. This paper discusses the potential impacts of biodegradable packaging materials and their waste management, particularly via composting. It presents the key issues that inform judgements of the benefits these materials have in relation to conventional, petrochemicalbased counterparts. Specific examples are given from new research on biodegradability in simulated 'home' composting systems. It is the view of the authors that biodegradable packaging materials are most suitable for single-use disposable applications where the post-consumer waste can be locally composted.

Biofibers. natural lignocellulosics, have an outstanding potential a s a reinforcement in thermoplastics. This study deals with the preparation of lignocellulosic composites by reactive extrusion processing in which good interfacial adhesion is generated by a combination of fiber modification and matrix modification methods. PP matrix was modified by reacting with maleic anhydride and subsequently bonded to the surface of the modified lignocellulosic component, in-situ. The fiber surface was modified by reacting it with a silane in a simple and quick aqueous reaction system, similar to that employed for glass fibers. The modified fibers are then extruded with the modified polymer matrix to form the compatibilized composite. The various reactions between the lignocellulosic fiber/filler and modified polymer chains, is expected to improve the interfacial adhesion significantly a s opposed to simple mixing of the two components, since new covalent bonds between the fiber surface and matrix are created in the former case. These composite blends were then injection molded for mechanical characterization. Typical mechanical tests on strength, toughness and Izod impact energy were performed and the results are reported. These findings are discussed in view of the improved adhesion resulting from reactions and enhanced polar interactions at phase boundaries.

The reversible kinetics of L-lactide bulk polymerization with tin(II) ethylhexanoate was determined over a wide range of temperatures, 130-220 °C, and monomer to initiator molar ratios, 1000-80 000. Both polymerization and depolymerization are accurately described by a reversible model with a propagation term that is first order in monomer and catalyst. The activation energy of propagation is 70.9 ( 1.5 kJ mol -1 . The enthalpy, entropy, and ceiling temperature of polymerization are -23.3 ( 1.5 kJ mol -1 , -22.0 ( 3.2 J mol -1 K -1 , and 786 ( 87 °C, respectively. Crystallization increases the propagation rate and decreases the apparent monomer equilibrium in proportion to the degree of crystallinity. Natural hydroxyl impurities stoichiometrically control the polymer molecular weight but do not significantly affect the propagation rate.

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