cellulose presentation
TRANSCRIPT
Gazi A Rahman NahidStudent ID: 120537
4 th year, 1st termForestry and Wood Technology Discipline
Khulna University
CELLULOSE
Gazi A Rahman Nahid (120537),FWT, KU
Cellulose Some Terminology Formation of cellulose Structure of cellulose Properties of cellulose Use of cellulose
Key of presentation
Gazi A Rahman Nahid (120537),FWT, KU
,1-4, D-Anhydro-glucopyranose units Liner homopolymer of Glucose Polysaccharide Molecular formula (C6H10O5 )n. Carbohydrate, composed of
Carbon, Oxygen and HydrogenDiscovered in 1838 by a French chemist.
“Anselm Payen”
Cellulose
Gazi A Rahman Nahid (120537),FWT, KU
Naturally occurring, most abundant organic substance ever
Main structural component of the cell wallReinforcing material in woodMost promising carbon sequestering deviceThe purest form is cotton fiber (about 98%)
Features of Cellulose
Gazi A Rahman Nahid (120537),FWT, KU
Glucose Simple Monosaccharide Pyranosic structure Hexose ( 6 carbon), also aldose( -CHO) Molecular formula is C6H12O6
Some Terminology
Gazi A Rahman Nahid (120537),FWT, KU
Pyranosic Structure ofGlucose (C6H12O6)
Gazi A Rahman Nahid (120537),FWT, KU
Terminology cont….PyranoseAny cyclic isomer, has a five carbons and one oxygen in a ring of six atoms
CellobioseCellobiose consists of two glucose molecules linked by a β(1→4) bond
Gazi A Rahman Nahid (120537),FWT, KU
Formation of Cellulose6
123
4 123
45 5
H2O
O
H2O
O
O O
1,4 D Glycopyranosic bond
,1-4, D-Anhydroglucopyranose units linked by (1,4)-glycosidic bonds
Cellulose synthase enzyme
Gazi A Rahman Nahid (120537),FWT, KU
Molecular Structure Crystal Structure Fibrillar Structure Capillary Structure
Structure of Cellulose
Gazi A Rahman Nahid (120537),FWT, KU
Unbranched chained polymer High molecular composition DP is 8000-10000 Distance between C-C and C-O is 1.9 to 2.1 (1= 10 -10 m)
Molecular Structure
Gazi A Rahman Nahid (120537),FWT, KU
Molecules can crystallize into different polymorphic forms.Only first four are of textile interest.Length of cellulose crystal is 10.3
Crystal Structure
Gazi A Rahman Nahid (120537),FWT, KU
Individual cellulose molecules are linked together to form an elementary fibril.Dimensions: about 4nm wide, 3 nm thick and 10nm long.
Fibrillar Structure
Gazi A Rahman Nahid (120537),FWT, KU
Capillary pores are opened up on exposure of solvent.Diameter ranges from 20nm to 10 micron.Surface area approximately 200sq.cm per gram for cotton fibre.
Capillary Structure
Gazi A Rahman Nahid (120537),FWT, KU
Intra and inter Hydrogen bonding
Gazi A Rahman Nahid (120537),FWT, KU
Crystalline region: Intra and Inter molecular bonding is so strong. Do not absorb much moistureAmorphous region: Bonding is week. Absorb too much moisture
Crystalline and Amorphous region
Gazi A Rahman Nahid (120537),FWT, KU
Appearance : Whitish in color Density : 1.5 g/cm3
Melting point : 260–270 °C; 500–518 °F; 533–543 K to decomposeStd enthalpy of formation : −963 KJ/mol Std enthalpy of combustion : −2828 KJ/mol Solubility in water : None Moisture absorption : 8-14% moisture, very
slowlyReacts with strong base
Properties of cellulose
Gazi A Rahman Nahid (120537),FWT, KU
Cotton: composed of 87 -90% cellulose with the cotton fibers containing polymer chains
Pharmaceuticals: Medicines are derived from plants cellulose, cellulose acetate etc.
Cellophane: Can be obtained when a viscous cellulose reacts with acid (sulfuric acid)
Bomb: Cellulose trinitrate is used as a propellant for bullets due the fact that nitrate –OH group can be explosive
Energy Drinks: Glucuronolacton, vitamins, and carbohydrates
Industrial Sugar, biofuel production, using oil production, ester production
Use of cellulose
Gazi A Rahman Nahid (120537),FWT, KU
Gazi A Rahman Nahid (120537),FWT, KU
Gazi A Rahman Nahid (120537),FWT, KU