Green composites prepared from aliphatic polyesters and bast fibers

In the recent years, the research about the use of natural cellulosic fibers as substitutes of the synthetic fibers (glass, aramid and carbon) used in the reinforcement of polymers, has been increased due to their biodegradability, lightness, reduced cost and favorable mechanical properties. Green composites are a particular class of biocomposites in which a biodegradable polymeric material is reinforced with natural fibers and represent a growing field in polymer technology. Such biodegradable polymers are usually aliphatic polyesters. The final properties of the composites are mainly depended on the kind of the fibers used, their aspect ratio, their volume fraction and orientation, and the adhesion strength on the fiber matrix interface. Hence, one of the challenges that researchers face today is to achieve satisfactory interfacial bonding which will result in products with better mechanical properties. Such composites could find more industrial applications and consequently would have greater commercial acceptance. However, this is difficult due to the hydrophilicity of the fibers and the hydrophobicity of used polyesters. In the particular review the advances on the preparation of green composites with bast fibers and aliphatic polyesters are discussed. Emphases are given on the summary of the literature and presentation of the effect of the different kinds of bast fibers on the final products. The treatments used to improve the properties of the aliphatic polyesters in order for the final composites to perform advanced mechanical and thermal properties as well as biodegradability are also reviewed. (C) 2014 Elsevier B.V. All rights reserved.