Mechanical properties biodegradable polymer nanocomposite

Biodegradable polymer nanocomposites have emerged as a new class of materials and attracted considerable interest and investment in research and development worldwide [76-79]. This is largely due to their new and often much improved mechanical, thermal, electrical and optical properties as compared to their macro- and micro- coimterparts. In general, polymer nanocomposites are made by dispersing inorganic or organic nanoparticles into either a thermoplastic or thermoset polymer [80-85]. Nanoparticles can be three-dimensional spherical and polyhedral nanoparticles (e.g.. 

Botana et al. [50] have prepared polymer nanocomposites, based on a bacterial biodegradable thermoplastic polyester, PHB and two commercial montmorillonites [MMT], unmodified and modified by melt-blending technique at 165°C. PHB/Na and PHB/ C30B were characterized by differential scanning calorimetry [DSC], polarized optical microscopy [POM], X-ray diffraction [XRD], transmission electron microscopy [TEM], mechanical properties, and burning behavior. Intercalation/exfoliation observed by TEM and XRD was more pronounced for PHB30B than PHB/Na,... 

Blending and compositing have been successfully used in starch-based materials. Starch was initially used a fillers blended with various polymers, especially with polyolefin. Blending starch with biodegradable polymers has attracted more and more attention. The interest in new nanoscale fillers has rapidly grown since it was discovered that a nanostructure could be built from a polymer and a layered nanoclay. These new nanocomposites show dramatic improvement in mechanical properties with low filler content. 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 feedstocks. Hydrophilic cellulose fibers are very compatible with most natural polymers. 

Hydrogels of CNCs have many desirable properties, including low cost, nontoxicity, hydrophilicity, biocompatibility, and biodegradability, all of which contribute to their potential applications in bioengineering and biomedicine. For example, CNC dispersed in a solution of cellulose, sodium hydroxide, and urea formed a gel that steadily released bovine semm albumin into a simulated body fluid [161]. Nanocomposites of CNC and poly(vinyl alcohol), a hydrophilic biocompatible polymer, exhibited a broad range of mechanical properties that could be tuned to mimic those of cardiovascular tissues and, therefore, have potential applications as cardiovascular implants [162]. 

Huisman GW, Wonink E, Meima R, Kazemier B, Terpstra P, Witholt B (1991) Metabolism of poly(3-hydroxyalkanoates) (PHAs) by Pseudomonas oleovorans. J Biol Chem 266 2191-2198 II Yun S, Gadd GE, LateUa BA, Lo V, Russell RA, Holden PJ (2008) Mechanical properties of biodegradable polyhydroxyalkanoates/single wall carbon nanotube nanocomposite films. Polym Bull 61 267-275... 

Biopolymeric nanocomposites can be easily made using nanoparticles that are derived from biobased polymers. This is an added advantage in terms of reducing inorganic content in the nanocomposites with improved mechanical properties and without affecting inherent biodegradability. 

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