Cellulose presentation

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


,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


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


Glucose Simple Monosaccharide Pyranosic structure Hexose ( 6 carbon), also aldose( -CHO) Molecular formula is C6H12O6

Some Terminology


Pyranosic Structure ofGlucose (C6H12O6)


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


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


Molecular Structure Crystal Structure Fibrillar Structure Capillary Structure

Structure of Cellulose


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


Molecules can crystallize into different polymorphic forms.Only first four are of textile interest.Length of cellulose crystal is 10.3

Crystal Structure


Individual cellulose molecules are linked together to form an elementary fibril.Dimensions: about 4nm wide, 3 nm thick and 10nm long.

Fibrillar Structure


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


Intra and inter Hydrogen bonding


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


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


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




Education

Cellulose presentation