Natural polymers nanocomposites

Fig. 1.1 Number of publications per year related to bionanohybrid materials. Data collected from the ISI Web of Knowledge [v3.0]-Web of Science. Keywords for search (biopolymer AN D nanocomposite ) OR (natural polymer AND nanocomposite ) OR (bio-nanohybrid ) OR (biohybrid AND nano ).

Above we have shown the attractiveness of the so-called green nanocomposites, although the research on these materials can still be considered to be in an embryonic phase. It can be expected that diverse nano- or micro-particles of silica, silicates, LDHs and carbonates could be used as ecological and low cost nanofillers that can be assembled with polysaccharides and other biopolymers. The controlled modification of natural polymers can alter the nature of the interactions between components, affording new formulations that could lead to bioplastics with improved mechanical and barrier properties. 

T. Ramanathan, A.A. Abdala, S. Stankovich, D.A. Dikin, M. Herrera-Alonso, R.D. Piner, et al., Functionalized graphene sheets for polymer nanocomposites, Nature Nanotechnology, 3 (2008) 327-331. 

M. A. Lopez-Manchado, B. Herrero, M. Arroyo, Organoday-natural rubber nanocomposites synthesized by mechanical and solution mixing methods, Polym Int, vol. 53, pp. 766-1772, 2004. 

This chapter reports the results of the literature that concerns the photooxidation of polymer nanocomposites. The published studies concern various polymers (PP, epoxy, ethylene-propylene-diene monomer (EPDM), PS, and so on) and different nanofillers such as organomontmorillonite or layered double hydroxides (LDH) were investigated. It is worthy to note that a specific attention was given to the interactions with various kinds of stabilizers and their efficiency to protect the polymer. One of the main objectives was to understand the influence of the nanofiller on the oxidation mechanism of the polymer and on the ageing of the nanocomposite material. Depending on the types of nanocomposite that were studied, the influence of several parameters such as morphology, processing conditions, and nature of the nanofiller was examined. 

Graphene-polymer nanocomposites share with other nanocomposites the characteristic of remarkable improvements in properties and percolation thresholds at very low filler contents. Although the majority of research has focused on polymer nanocomposites based on layered materials of natural origin, such as an MMT type of layered silicate compounds or synthetic clay (layered double hydroxide), the electrical and thermal conductivity of clay minerals are quite poor [177]. To overcome these shortcomings, carbon-based nanofillers, such as CB, carbon nanotubes, carbon nanofibers, and graphite have been introduced to the preparation of polymer nanocomposites. Among these, carbon nanotubes have proven to be very effective as conductive fillers. An important drawback of them as nanofillers is their high production costs, which... 

The fundamental knowledge on the preparation and nature of metal-polymer nanocomposites has a long history that is connected to the names of many famous scientists. The oldest technique for the preparation of metal-polymer nanocomposites that can be found in the literature was described in an abstract that appeared in 1835. In an aqueous solution, a gold salt was reduced in the presence of gum arabic, and subsequently a nanocomposite material was obtained in the form of a purple solid simply by coprecipitation with ethanol. Around 1900, widely forgotten reports describe the... 

The pol5mier nanocomposite field has been studied heavily in the past decade. However, polymier nanocomposite technology has been around for quite some time in the form of latex paints, carbon-black filled tires, and other pol5mier systems filled with nanoscale particles. However, the nanoscale interface nature of these materials was not truly understood and elucidated until recently [2 7]. Today, there are excellent works that cover the entire field of polymer nanocomposite research, including applications, with a wide range of nanofillers such as layered silicates (clays), carbon nanotubes/nanofibers, colloidal oxides, double-layered hydroxides, quantum dots, nanocrystalline metals, and so on. The majority of the research conducted to date has been with organically treated, layered silicates or organoclays. 

The fundamental knowledge on the preparation and nature of metal-polymer nanocomposites has a long history, connected to the names of many illustrious scientists [Caseri, 2000]. The oldest technique for the preparation of metal-polymer... 

Natural Polymers Their Blends, Composites and Nanocomposites State of Art, New Challenges and Opportunities... 

Abstract The present chapter deals with a brief account on various types of natural polymers such as cellulose, chitin, starch, soy protein, casein, hemicellu-loses, alginates, polylactic acid and polyhydroxyalkanoates etc. Blends, composites and nanocomposites based on these polymers have been very briefly discussed. Finally the applications, new challenges and opportunities of these biomaterials are also discussed. 

Fibers have been widely used in polymeric composites to improve mechanical properties. Cellulose is the major substance obtained from vegetable fibers, and applications for cellulose fiber-reinforced polymers have again come to the forefront with the focus on renewable raw materials. Hydrophilic cellulose fibers are very compatible with most natural polymers. The reinforcement of starch with ceUulose fibers is a perfect example of a polymer from renewable recourses (PFRR). The reinforcement of polymers using rigid fillers is another common method in the production and processing of polymeric composites. The interest in new nanoscale fillers has rapidly grown in the last two decades, since it was discovered that a nanostructure could be built from a polymer and layered nanoclay. This new nanocomposite showed dramatic improvement in mechanical properties with low filler content. Various starch-based nano-composites have been developed. 

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