Natural fibres surface modification

Belgacem M.N., Gandini A., Natural Fibre-Surface Modification and Characterisation, in Cellulose Fibre Reinforced Polymer Composites (Eds. Sabu T. and Pothan L.), Old City Publishing, 2007. Chapter 3... 

Keywords Bacterial cellulose Hierarchical composites Mechanical properties Natural fibres Surface modification... 

As ToF-SIMS is a surface analytical technique, it is well suited to the study of surface interaction between a material and its environment or between a material and products applied to it. The surface modifications can then be studied, making it possible to establish links with degradation processes. Published papers on the study of natural fibres related to cultural heritage typically illustrate this aspect of ToF-SIMS analysis. 

Denter, U., Schollmeyer, E., 1996. Surface modification of synthetic and natural fibres by fixation of cyclodextrin derivatives. Journal of Inclusion Phenomena and Molecular Recognition in Chemistry 25, 197—202. 

Sun, D., and Stylios, G. K. (2005). Investigating the plasma modification of natural fibre fabrics-the effect on fabric surface and mechanical properties, TextRe., 75, 639-644. 

The previous three sections involved the treatment of natural fibres by removing substances from the natural fibres. This section, however, describes a new modification that does not involve the removal but the addition of new material onto the surface of natural fibres. This type of modification involves the deposition of nanosized cellulosic materials onto the surface of natural fibres to enhance the interfacial adhesion between the fibres and the matrix [9,10,14,104]. By doing so, a hierarchical structure can be created. These works were inspired by nature. Nature maximises the efficiency of structural materials by creating hierarchical stmctures the arrangement of the constituents at every level, from the molecular level to the macroscopic level. By applying this concept, composites that possess a hierarchical structure with improved mechanical properties can be manufactured. 

Simple weight gain measurements showed that approximately 5-6 wt% of BC was deposited onto the surface of these natural fibres. However, the mechanical properties of the natural fibres after bacterial cellulose modification depend on the... 

Hepworth DG, Hobson RN, Bruce DM, Farrent JW (2000) The use of unretted hemp fibre in composite manufacture. Compos A 31 1279-1283 Idicula M, Boudenne A, Umadevi L, Ibos L, Candau Y, Thomas S (2006) Thermophysical properties of natural fibre reinforced polyester composites. Compos Sci Technol 66 2719-2725 Ioffe R, Andersons J, Wallstrom L (2003) Strength and adhesimt characteristics of elementary flax fibers with different surface treatments. Compos A 34 603-612 John MJ, Anandjiwala RD (2008) Recent developments in chemical modification and characterization of natural fiber-reinforced composites. Polym Compos 29 187-207 John MJ, Anandjiwala RD, Thomas S (2009) Hybrid cranposites. In Thomas S, Pothan LA (eds) Natural fiber reinforced polymer composites macro to nanoscale. Old City, Philadelphia, pp 315-328... 

Mohanty AK, Parija S, Misra M (1996) Ce(IV)-A(-acetylglycine initiated graft copolymerization of acrylonitrile onto chemically modified pineapple leaf fibers. J Appl Polym Sci 60 931-937 Mohanty AK, Khan MA, Hinrichsen G (2000) Surface modification of jute and its influence on performance ofbiodegradable jute-fabric/Biopol composites. Compos Sci Technol 60 1115-1124 Mohanty AK, Misra M, Drzal LT, Selke SE, Harte BR, Hinrichsen G (2005) Natural fibers, biopolymers and biocomposites an introduction. In Mohanty AK, Misra M, Drzal LT (eds) Natural fibers, biopolymers and biocomposites. Taylor Francis, FL, Boca Raton Mukherjee PS, Satyanarayana KG (1986) Structure and properties of some vegetable fibres Part 2 pineapple fiber. J Mater Sci 21 51-56... 

However, lack of good interfacial adhesion, low melting point, and poor resistance towards moisture make the use of natural fibre-reinforced composites less attractive. Pre-treatments of the natural fibre can clean the fibre surface, chemically modify the surface, stop the moisture absorption process and increase the surface roughness. Among the various pre-treatment techniques, graft copolymerization and plasma treatment are the best methods for surface modification of natural fibres. Graft copolymers of natural fibres with vinyl monomers provide better adhesion between matrix and fibre. 

The quality of the fibre-matrix interface is significant for the application of natural fibres as reinforcement fibres for plastics. Physical and chemical methods can be used to optimise this interface. These modification methods have a different efficiency for the adhesion between matrix and fibre. Accordingly, one has to modify the surface of the fibres or the chemical structure of the plastic or use coupling agents. 

Use of natural fibre composites. A large number of papers has been published on the advantage of using natural fibres as well as wood flour [94—96], which are to be light, renewable, and environmentally friendly. Research is focused in improving interfadal adhesion by surface treatment, chemical modification. More research is needed to develop practically viable methods to use these fibres. In spite of these difficulties, a large increase is expected in the use of such materials [97]. 

X.J. Dai, L. Kviz, Study of Atmospheric and Low Pressure Plasma Modification on the Surface Properties of Synthetic and Natural Fibres, in An Odyssey in Fibres and Space, Textile Institute 8P World Conference Melbourne, Australia (2001). 

Alkali treatment Mercerization or alkali treatment with strong alkali bases was developed as a method for cotton fibre modification by John Mercerin 1850 [55], It is a common method to produce high quality natural fibres, by removing the natural and artificial impurities from the fibre surface. The chemical treatment reduces the fibre diameter and thereby increases the aspect ratio [26]. Mercerization is usually performed applying aqueous solutions of sodium hydroxide (NaOH), at reaction times of 30 min up to 3 hr. 

Mohanty A K, Misra M and Drzal L T (2001), Surface modifications of natural fibres and performance of the resulting biocomposites , Comp Interfaces, 8 (5), 313-343. 

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