Nanocomposites life cycles

However, the use of nanoparticles in nanocomposites may also have less desirable side effects. For instance, thermo-oxidative stability may be reduced, which may have negative consequences for performance and service time [13,14]. Furthermore, polymer degradation under solar irradiation may be increased, and hazardous nanoparticles may be released during their life cycle (which starts with resource extraction and ends with final disposal) [15,16]. The release of engineered nanoparticles from nanocomposites and the scope for reduction of hazard and risk to health during the nanocomposite life cycle are considered in this chapter. This chapter also deals with other environmental aspects of... 

Nanocomposite Life Cycles and Life Cycle Assessment 281... 

A problem with life cyde assessment of nanocomposites is that so far no generally agreed upon way has been found to deal with the health hazard and risk associated with nanoparticles [34]. An important reason for this is that human toxicity and ecotoxicity are normally linked to the emitted mass of substances, whereas the determinants of nanoparticle hazards are, as pointed out in the previous section, factors such as number of particles and surface characteristics. An additional problem is that there may be size-dependent nonlinearities in the relation between surface and hazard to human health [26]. The same may hold for ecotoxicity [26]. However, the other aspects indicated in Box 12.1 pose no insurmountable problem to nanocomposite life cycle assessment. 

Nanocomposite Life Cycle Management, Including Recycling... 

Reducing Nanoparticle-Based Health Hazards and Risks Associated with Nanocomposite Life Cycles... 

On the basis of available research, there are leads to the reduction of nanocomposite life cycle hazards and risks. 

Life cycles of nanocomposites can give rise to the release of inorganic nanoparticles. These may be hazardous, depending on characteristics such as size, shape, and surface. There are options to reduce the release of nanoparticles and the hazards and risks thereof during the nanocomposite life cycle. These include judicious choices regarding production processes, materials design, containment, particle size and crystal structure, coating, and functionalization. 

Concerns regarding the toxicity and environmental effects of polymer-based nanocomposites, such as those derived from clay nanoparticles or carbon nanotubes, throughout their life cycle, from formulation, polymerisation, compounding, fabrication, use, disposal and degradation, are described. The potential of nanoparticles to enter the body by skin contact or inhalation is discussed. Accession no.927669... 

Lloyd, S. and Lave, L. (2003) Life cycle economic and environmental implications of using nanocomposites in automobiles. Environ. Sci. Technol., 37, 3458-3466. 

The correct balance has to be found between the durability of the packaging needed for the preservation of packed food during its shelf-life, and the expected biodegradability at the end of the life cycle. Addition of nanocomposites in PLA can improve barrier properties for food applications and increase degradation in compost conditions [217]. On the other hand, plasticizers are commonly added to promote flexibility of PLA but degradation increases, and food shelf life is often negatively affected by increasing plasticizer content [89]. 

Since the initial absorption (i.e. color) of the nanocomposite increases with montmorillonite addition, future investigations should focus on examining synthetic aluminosilicates that do not contain isomorphic substitution from transition metals such as Fe. Alternative types of inorganic fillers include laponite, fluorohectorite or synthetic silicic acids (31). Note that the UV exposure is not only an on-orbit concern, but will drastically affect life-cycle and long-term environment stability and performance of nanocomposites used in external terrestrial environments. 

The chapter demonstrates that in spite of the incompatibility between hydrophilic natural fibres and hydrophobic polymeric matrices, the properties of natural fibre composites can be enhanced through chemical modifications. The chemical treatments have therefore played a key role in the increased applications of natural fibre composites in the automotive sector. Recent work has also shown that if some of the drawbacks of natural fibres can be adequately addressed, these materials can easily replace glass fibres in many applications. The chapter has also shown that there have been attempts to use natural fibre composites in structural applications, an area which has been hitherto the reserve of synthetic fibres like glass and aramid. The use of polymer nanocomposites in applications of natural fibre-reinforced composites, though at infancy, may provide means to address these efficiencies. Evidence-based life-cycle assessment of natural fibre-reinforced composites is required to build confidence in the green composites applications in automotive sector. 

This book on natural rubber presents a summary of the present state-of-the-art in the study of these versatile materials. The two volumes cover all the areas related to natural rubber, from its production to composite preparation, the various characterization techniques and life cycle assessment. Chapters in this book deal with both the science of natural rubber - its chemistry, production, engineering properties, and the wide-ranging applications of natural rubber in the modern world, from the manufacture of car tyres to the construction of earthquake protection systems for large buildings. Although there are a number of research publications in this field, to date, no systematic scientific reference book has been published specifically in the area of natural rubber as the main component in systems. We have developed the two volumes by focusing on the important areas of natural rubber materials, the blends, IPNs of natural rubber and natural rubber based composites and nanocomposites their preparation and characterization techniques. The books have also profoundly reviewed various classes of fillers like macro, micro and nano (ID, 2D and 3D) used in natural rubber industries. The applications and the life cycle analysis of these rubber based materials are also highlighted. 

Journal of Biobased Materials and Bioenergy. 2007- Valencia, CA American Sdentilic Publishers (1556-6560). Online at http //www.aspbs.com/jbmbe/ (1556-6579). Publishes research on biobased polymers and blends, biobased composites and nanocomposites, biobased materials processing technologies, life-cycle analysis, social and environmental impacts, and biofuels. 

Nanocomposites have a cradle (resource extraction) and a grave (final disposal). Between the two is the life cycle. A life cyde may indude one product, but may also extend to a series of products. For instance, nanocomposite rubber tires may be subject to recyding, and thus the nanocomposite rubber material may end up in new rubber products or asphalt. 

When thinking about the environmental effects of plastics, for the products having short life cycle periods - if the mechanical aspects can be fulfilled - it may be convenient to use biodegradable materials. Considering the promising properties and applications of biodegradable polymers as long as their environmental friendly aspects, we decided to start with PLA-clay nanocomposites. 

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