chapter 3 synthetic fibres and plastics
TRANSCRIPT
INTRODUCTION
•THE CLOTHES WHICH WE WEAR ARE MADE OF FABRICS.
•FABRICS ARE MADE FROM FIBRES.
•THE FIBRES ARE OBTAINED FROM NATURAL OR ARTIFICIAL SOURCE.
NATURAL FIBRES
•THE FIBRES THAT ARE OBTAINED
FROM PLANTS OR ANIMALS ARE
CALLED NATURAL FIBRES.
•EXAMPLES : - COTTON , WOOL ,
SILK , JUTE , etc.
SYNTHETIC FIBRES
• THE FIBRES MADE BY HUMAN BEINGS ARE
CALLED SYNTHETIC FIBRES OR MAN MADE
FIBRES OR ARTIFICIAL FIBRES.
• SYNTHETIC FIBRES ARE MADE FROM
DIFFERENT CHEMICALS , HENCE EACH KIND
OF SYNTHETIC FIBRES HAVE THEIR OWN
PROPERTIES.
WHAT ARE SYNTHETIC FIBRES
• A SYNTHETIC FIBRE IS A CHAIN OF SMALL
CHEMICAL UNITS JOINED TOGETHER .
• EACH SMALL UNIT IS CALLED A
MONOMER.
• A LARGE CHAIN FORMED BY MANY
MONOMERS IS CALLED A POLYMER.
•THE WORD “POLYMER”
COMES FROM TWO GREEK
WORDS ;
POLY MEANING MANY
MER MEANING PART / UNIT.
SO A POLYMER IS MADE OF
MANY REPEATING UNITS
• THE STRUCTURE OF
POLYMER CAN BE
COMPARED TO THAT
OF A BEAD NECKLACE
– THE BEAD BEING
MONOMERS .
• THE PROCESS OF
COMBINING THE
MONOMERS TO FORM A
POLYMER IS CALLED
POLYMERISATION.
RAYON
•RAYON IS PREPARED BY CHEMICAL TREATMENT OF WOOD PULP.
• IT IS ALSO CALLED ARTIFICIAL SILK.
•ALTHOUGH RAYON IS OBTAINED FROM A NATURAL SOURCE (WOOD PULP) , YET IT IS A MAN MADE FIBRE.
PROPERTIES OF RAYON
EASILY DYED AND
WOVEN INTO
CLOTH
CHEAPER THAN SILK
LUSTROUS IN APPEARANCE
GOOD ABSORBENT OF SWEAT
USES OF RAYON
•RAYON IS MIXED WITH
COTTON TO MAKE BEDSHEETS
•RAYON IS MIXED WITH WOOL
TO MAKE CARPETS.
NYLON
• IN 1931 , IT WAS MADE WITHOUT
USING ANY NATURAL RAW MATERIAL
( FROM PLANTS OR ANIMALS )
• IT WAS PREPARED FROM COAL , WATER
AND AIR.
• IT WAS THE FIRST FULLY SYNTHETIC
FIBRE
USES OF
NYLON
PARACHUTE
SLEEPING BAGS
CAR SEATBELTS
TOOTHBRUSH
TENTS ROPES
SOCKS
ROPES FOR
ROCK CLIMBING
CURTAINS
POLYESTER
• POLYESTER (POLY + ESTER ) IS MADE UP
OF THE REPEATING UNITS OF A
CHEMICAL CALLED AN ESTER
• ESTERS ARE CHEMICALS WHICH GIVE
FRUITS THEIR SMELL
• FABRIC MADE FROM POLYESTER
DOESNOT GET WRINKLED EASILY
USES
• TERYLENE IS POPULAR POLYESTER WHICH
CAN BE DRAWN INTO VERY FINE FIBRES .
• PET IS A FORM OF POLYESTER WHICH IS
USED FOR MAKING BOTTLES ,UTENSIL ,
FILMS , WIRES AND MANY OTHER USEFUL
PRODUCTS
ACRYLIC
•ACRYLIC IS A SYNTHETIC FIBRE.
•DUE TO ITS WOOL-LIKE
FEEL,ACRYLIC FIBRE IS OFTEN
USED AS A SUBSTITUTE FOR
WOOL.
PROPERTIES
RESISTANT TO MOTHS
SOFT WITH CRIMPS
RESEMBLING WOOL
IS DURABLE LIGHT AND WASHABLE
STRONG AND STAIN RESISTANT
WARM AND LIGHT
WEIGHT
CAN BE DYED IN
DIFFERENT COLOURS
USES
ACRYLIC KNITTING WOOL IS GOOD FOR BABY AS IT IS SOFT , WARM AND
WASHABLE
USED FOR MAKING ARCYLIC FUR , BLANKETS
CARPETS
TRANSPARENT TYPE OF ACRYLIC IS USED TO COVER CAR HEADLIGHT ,
LENSES , SURGICAL
EQUIPMENTS
CHARACTERISTICS OF SYNTHETIC FIBRES
SYNTHETIC FIBRES ARE-
• STRONG
• DURABLE
• WRINKLE RESISTANT
• LIGHTWEIGHT
• EXTREMELY FINE
• NOT ATTACKED BY MOTHS
• LESS EXPENSIVE
• READILY AVAILABLE