Polypropylene fib
Polypropylene fibres
Polypropylene fibres are a manufactured olefin fibre made from polymers or copolymers of propylene, (34)
Polypropylene fibre (PP) continues to be the raw material of choice for the geotextile industry , as polypropylene based geotextiles comprise about 90% of the geotextile market. (39)
Needle punched polypropylene is still one of the largest products for geotextile and related applications in drainage and asphalt resurfacing.(40)
Polypropylene fibres have a very distinguished properties which made it suitable for being used in geotextiles sector :
1-Chemical resistance
Polypropylene fibres have excellent resistance to most chemicals .In particular they are unaffected by all organic solvent , acids , alkaline solutions as can be found in soil component. (41)
2-Low density
Polypropylene is the lightest of all fibres with a specific gravity of only 0.91 g/cm3. In geotextiles it is an advantage to have a good beefy with a very light weight .(42)
3-Water resistance
Fibres which absorb water can in some cases provide a home for bacteria , where they breed and eventually rot the fabric. Polypropylene fibres have the lowest water absorption of all synthetics ( moisture regain is zero) which made this fibre the most appropriate for geotextiles , as these fabrics need to be rot- proof and long lasting. (43)
4-Abrasion resistance
Polypropylene has a high abrasion resistance , similar to polyester fibres, and has extremely good resistance to repeated bending making it advantageous for the rough handling on a construction site. (42)
5- Strength
polypropylene fibres have excellent strength , which is dependent on the degree of polymerization. (38)
6- Low extension under load
7- Resistance to micro – organisms and insects
Polypropylene fibres are very resistant to attack by bacteria , mildew, and insects (44)
Besides all this polypropylene has two major economic advantages , it has a short simple route and is easily obtainable from oil or natural gas. Also it has a relatively low melting point (260 0 F), this means that energy costs and capital costs are lower than other polymers. (42)
In road paving application, polypropylenes are often the fibre of choice due to their excellent physical properties , hydrophobicity , resistance to acids, mildew resistance , low density and low cost. (45)
Because of the excellent physical and chemical properties of these two fibres ( polyester and polypropylene ) , they were used with confidence and were considered the material of choice in this research.
