Natural vegetal fibres

Fig. 1.2 Structural constitution of natural vegetable fibre eell [18]...

Fibrillar fines obtained from cellulosic fibres are known for their unique structure, material characteristics, and potential applications (Hubbe et al. 2008). An amorphous lignin and hemicellulose matrix separates the elementary nanofibrils in natural vegetable fibres. Based on raw material sources, pretreatment and subsequent defibrillation procedures will produce a broad spectrum of fibril structures as well as nomenclatures used to describe them. Thus, we find various terms adopted in the field, such as nanoscale-fibrillated cellulose, cellulosic fibrillar fines, cellulose aggregate fibrils, and microfibrillar cellulose. 

Textile reinforcement with natural vegetal fibres or with glass fibres is particularly vulnerable to alkaline corrosion (cf. Sections 5.3 and 5.8). 

The problems related to safe and durable roofs for low cost houses are usually more difficult than those for walls and other elements of the house. For that reason, various kinds of low-cost fibre reinforcement are used in regions where cellulose pulp (in Nordic countries) and natural vegetal fibres (in tropical and subtropical countries) are available (cf. Section 5.7). 

Namral vegetable fibre/plasticised natural vegetable fibre-a candidate for low cost and fully biodegradable composite. 

H.M. (1999) Natural vegetable fi-bre/plasticised natural vegetable fibre-a candidate for low cost and fully biodegradable composite. Adv. Compos. Lett., 8, 231-236. 

G. Lewis and P. Mirihagalia, Natural vegetable fibres as reinforcement in cement sheets , Mag. Conor. Res. 31,1979,104-108. 

As it is now possible by choice of suitable conditions to prepare most compounds in this form, the colloid state should be considered as a physical state in which all substances can be made to exist. Many ma terials such as proteins, vegetable fibres, rubber, etc. are most stable or occur naturally in the colloidal slate. In the colloidal stale the properties of surface are all-important. 

See A Cappelli Behaviour to tintonal analysis of naturally coloured animal and vegetable fibres. Ann. Labor. Chtm. centrale GabeUe, Vol. VII, p. 213. 

It is almost paradoxical that in the history of mankind composite materials were earlier used than their "homogeneous" rivals. The earliest "engineering materials" were bone, wood and clay. Wood is a composite of matrix lignin and a cellulosic reinforcement bone is a natural composite where fibres of hydroxyapatite reinforce the collagen matrix and the oldest building material was adobe clay as a matrix, reinforced by vegetable fibres. After the industrial revolution other composites were added reinforced rubber, reinforced concrete, reinforced asphalt, etc. 

Biagiotti, J., Puglia, D., and Kenny Jose, M. A Review on Natural Fibre-Based composites-Part I Structure, Processing and Properties of vegetable Fibres, J. Nat. Fibers, 1(2), 37-68, 2004 Italicized data from McGovern, J.N. Fibers, vegetable. In Polymers— Fibers and Textiles. A compendium. University of Wisconsin, Madison, WI, 1990. 

Biagiotti, J. Puglia, D. Kenny, Jose M. A review on natural fibre-based composites-Part I structure, processing and properties of vegetable fibres. Journal of Natural Fibers, 2004, Vol. 1 Issue 2, pp. 37-68. 

The chemical composition as well as the morphological microstmcture of vegetable fibres is extremely complex due to the hierarchical organisation of the different compounds present at various compositions. Depending on the type of fibre, the chemical composition of natural fibres varies. Primarily, fibres contain cellulose, hemicellulose and lignin. The property of each constituent contributes to the overall properties of the fibre. 

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... 

In this section, man-made fibres, other than metallic, glass and natural vegetal, are considered. Carbon fibres are described in Section 5.7. 

Abaca is considered the strongest of natural fibres, being three times stronger than sisal fibre, and is far more resistant to saltwater decomposition than most of the vegetable fibres. Compared to synthetic fibres like rayon and nylon, abaca fibre possesses higher tensile strength and lower elongation in both wet and dry states. 

The fibres used for natural geotextile products are plant or vegetable fibres, although some research and development studies have considered the use of very low grade sheep s wool and wool waste. Figure 11.1 shows a classification of well known natural fibres. However, the only ones that meet with the technical requirements, cost effectively, are the bast fibres jute, hemp, kenaf and flax (also called soft fibres because they are from the softer region of the plants), and the hard (or leaf) and fruit fibres sisal and coir. Others of the remaining fibres, e.g. wood fibres, are sometimes used as fillers within the textile structure. 

Natural fibres include those collected from natural source according to their origin, natural fibres are further grouped into three classes vegetable, animal and mineral. Vegetable fibres contain cellulose as a fundamental constituent whereas animal-based fibres are protein, eg, silk and wool. Asbestos is example of a mineral fibre. 

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