Bio-based nanocomposites [Elektronisk resurs]

• The use of cellulose nano-whiskers as reinforcements in biodegradable polymeric systems is a relatively new field in nanotechnology and has attracted significant attention during the last decade. In spite of various challenges in this research area, cellulose bionanocomposites with polymer matrices and nano reinforcements derived from renewable resources are being studied by researchers. It can be considered that this research area is at its infancy and lot of interdisciplinary research is required to scale it up to a commercial level. The major challenges in area of nanocomposite research are the efficient separation of nanowhiskers from natural resources, compatibilization of the nanoreinforcements with the matrix, development of suitable methods for processing these novel biomaterials, together with the energy consumption factor and the cost factor involved with novel biomaterials. Cellulose nanowhiskers (CNWs) are of great interest due to their renewable nature, good mechanical properties and large specific surface area. The theoretical elastic modulus of cellulose whiskers has been calculated to be 167.5 GPa, by Tashiro and Kobayashi (1). When used as reinforcement in biopolymers like starch, cellulose acetate (CA) or polylactic acid (PLA) it will lead to development of new biodegradable and environmental friendly nanocomposites. This new type of composites is expected to have remarkable improvement of material properties when compared with the pristine matrix polymers or conventional micro- and macro-composite materials. Such improvements can include higher modulus and strength, decrease in gas permeability, increase in heat distortion temperature and also an increase in the biodegradability of biodegradable polymers. Earlier studies have shown that cellulose whiskers have a potential to act as reinforcement for polymers but these studies have mainly been done using hydro soluble polymer systems where the polymers mechanical properties are very low (2,3). Later on, studies have shown different biopolymers in combination with cellulose nanowhiskers and how the use additives and processing aids etc have been used to obtain stable colloidal dispersion of nanowhiskers capable of interacting with biopolymer matrices (4,5). We have also studied the cellulose nanocomposite processing to identify efficient and compatible bionanocomposite systems and take this to an industrially viable level (6-10). The studies on nanocomposite structure and properties have enabled the optimization of the process as well as the performances. Our aim have been to develop bionanocomposites with good mechanical properties, barrier properties, thermal stability and transparency and at the same time develop an energy efficient and cost effective processing methodology. We have made nano-composites, by solution casting and twin screw extrusion and aligned whiskers using magnetic field (8-10). The separated cellulose whiskers as well as the prepared nanocomposites have been characterized using birefringence and different microscopy technologies, optical microscope (OM), field emission scanning electron microscope (FE-SEM), atomic force microscope (AFM) and transmission electron microscope (TEM). The composites thermal and mechanical properties were studied using dynamic mechanical thermal analysis (DMTA) and tensile testing. 

Ämnesord

Engineering and Technology  (hsv)

Industrial Biotechnology  (hsv)

Bio Materials  (hsv)

Teknik och teknologier  (hsv)

Industriell bioteknik  (hsv)

Biomaterial  (hsv)

Trä och bionanokompositer  (ltu)

Wood and Bionanocomposites  (ltu)