PHB-Based Nanocomposites

Because of waste accumulation at the end of the life cycle of traditional polymer products, the development of environment-friendly, degradable polymeric materials has attracted extensive interest [6]. PHB is one of these types of polymers. 

In order to obtain a competitive product, the PHB performance can be greatly enhanced with the addition of nanometer-size inorganic fillers. This kind of materials are called nanocomposites and have an interesting characteristic The mechanical properties [42], the barrier properties [43], the thermal properties [44], and some others such as the flammability [45], water adsorption [46], and creep resistance [47] can be greatly enhanced with the addition of a small amount of filler (usually less than 10 wt%) [6,42-48]. 

Among all the nanofillers that have been studied within nanocomposites combinations with PHBs, clay is the most widely reported in the literature. This chapter will therefore focus mainly on the former as well as briefly afterward on nanocellulose. 

One kind of nanometer-size reinforcement is the montmo-rillonite, which is a layered silicate whose interlayer ions can be exchanged by organ-ions in order to produce an increment in the interlayer spacing (dooi3 snd to improve the polymer/clay compatibility. These improvements allow the dispersion of clay platelets to be easier [49]. 

The selection of the best clay for a specific matrix is crucial to obtain nanocomposites with optimized properties. A series of the most commonly used montmorillonites are summarized in Table 24.5. 

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