Processing Technology

1. Discuss processes of
natural fibers
reinforced
thermoplastic and
thermoset
PTT260/3
Bioresource Processing
Technology
By: Dr Rosniza Hamzah
Fiber and
Lignocellulosic
Composite
Chapter 6 & 7:

2. What is fiber?
• Fiber is a natural or synthetic substance that is significantly
longer than it is wide.
• Fibers are often used in the manufacture of other materials
• The strongest engineering materials often incorporate fibers.
• Carbon fiber (for bicycle)
(lightweight, rigidity, strength, resistance to stretching)
• Ultra-high molecular weight polyethylene (bearing)
(very light, extremely tough, chemically resistant,
excellence wear resistance, abrasive materials)
Wood fiber Rice straw fiber Nylon fiber

3. • Plants (vegetable and wood fiber), animals, and
geological processes. They are classified according to
their origin:
• Vegetable fiber are generally based on arrangements
of cellulose and lignin.
• Example: cotton, hemp, jute, flax, baggase,
• Vegetable fiber in manufacturing of paper and textile (cloth),
dietary fiber (an important component of human nutrition).
• Wood fiber is distinguish from vegetable fiber.
• From tree sources i.e groundwood, lacebark,
thermomechanical pulp (TMP), and bleached or
unbleached kraft or sulfite pulps.
Sources of natural fiber

4. • Kraft and sulfite (also called sulphite) refer to the type of
pulping process used to remove the lignin bonding the original
wood structure, thus freeing the fibers for use in paper
and engineered wood products such as fiberboard.
• Animal fibers consist largely of particular proteins
(silk, hair, fur).
• Example: silkworm silk, spider silk, catgut, wool
cashmere wool, mohair, angora
sheepskin, rabbit, squirrel, fox, beaver etc.
• Fiber from geological processes is known as mineral fibers
• Mineral fibers includes asbestos group
• Asbestos is the only naturally occurring long mineral fiber.
• Six minerals have been classified as "asbestos“
chrysotile, amosite, crocidolite, tremolite, anthophyllite, actinolite.
• Wallastonite and palygorskite are short fiber-like minerals

5. • Other fibers are biological fibers
• Known as fibrous proteins or protein filaments
• Consist largely of biologically relevant and biologically
very important proteins, mutations or other genetic
defects can lead to severe diseases
• Examples: collagen
family of proteins (tendon, muscle, cell)

6. Advantages and Disadvantages
of Natural fiber
Advantages:
i) Comfortable: Clothes made by natural fibres are more comfortable
than those made of synthetic fibres.
ii) Environment: Producing materials from natural fibres are less
harmful to our environment.
iii) Non allergic to skin

7. Disadvantages:
• Expensive
• Shrink (due to aggressive washing)
• Low tenacity while synthetic medium and high tenacy)
• Low degree of resiliency
• Production of natural fibres cannot be completely controllable
• Product variation and pricing
(variation and price)
• The availability of natural fibres is affected by natural calamities
and vagaries of nature.
• The production of natural fibres involves the use of land which is
also required for growing the agriproducts.
Advantages and Disadvantages
of Natural fiber

8. Advantages and Disadvantages
of Synthetic fiberAdvantages:
• Strong (can take up heavy things easily)
• Retain their original shape (easy to wash and wear)
• Elastic (easily be stretched out)
• Soft
• Varieties of colours
• Cost (cheaper than natural fiber)
• Producible in specific qualities of fibres
• Fine and coarse filaments
• Final product do not require cleaning
• Colour can be incorporated during the production of the fiber
• Easy care properties (wrinkle resistance, crease recovery)
• Light weight
• Most of the synthetic fibres possess high resistance to moth,
mildew, insects, mould, which simplify the storage problems, the
economy of little loss from these causes.

9. Advantages and Disadvantages
of Synthetic fiber
Disadvantages:
• Does not absorb moistures
• Rough feel (for certain clothing only)
• Some individuals are often prone to skin allergy, because of
the dermatological action of manmade fibres. This puts a
restriction on its use (such problems do not arise in the case
of natural fibres).
• Hydrophobic in nature (this is necessarily a disadvantage
when their products have to be worn next to the skin)
• Fail to absorb the perspiration (wearer feels discomfort in a
hot climate)
• Difficult to sew (Seams do not hold tight as in natural fibre
fabrics i.e lycra

10. Thermoplastics
• Thermoplastic known as thermosoftening plastic
• Behaves like a plastic material
• Moldable above a specific temperature and solidifies upon
cooling
• High MW polymer
• Upon heating, intermolecular forces amongst the polymer
chains are weaken, polymers turns to a viscous liquid.
• Thus, thermoplastics may be reshaped by heating and are
typically used to produce parts
• Processing technique: injection molding, compression molding,
calendaring, extrusion.
• Thermoplastics differ from thermosetting polymer
• During curing, formation of chemical bond is irreversible
• Thermosets do not melt, but decompose and do not reform
upon cooling.

11. List of Thermoplastics
• Nylon
• Polylactic Acid
• Polybenzimide
• Polycarbonate
• Polypropylene
• Polystyrene
• Polyvinylchloride
• Teflon

12. Thermoset
• Thermoset known as thermosetting resin
• Physically as soft solid or viscous liquid state
• The physical state changes irreversibly into an infusible,
insoluble polymer network by curing.
• Curing is induced by the action of heat, radiation, catalyst,
crosslinking agent
• Thermoset need to be cured during usage i.e polymer matrix

13. List of Thermoset
• Polyester resin
• Polyurethane
• Vulcanized rubber
• Phenol-formaldehyde resin
• Melamine resin
• Epoxy resin
• Polyimide

14. Fibers Reinforced Thermoplastic
and Thermoset
• Applied during fabrication of factory finished structural
composites
• Why use filler?
• To improves mechanical properties of the material
i.e elastic modulus, hardeness, fracture strength,
fracture toughness, fatigue
• Filler or particles typically aggregates in the polymer matrix
• Why aggregates?
• need to use coupling agent as surface modifier, one site bind
to the polymer another bind to the filler
• other way; hybrid