Cellulose Plastics
CORPORATE TRAINING AND PLANNING
Cellulose Plastics
Introduction

Cellulose is a natural polymer produced from wood via
wood pulp.

Woven grade cotton contains about 90% cellulose while
an average wood has about 50% and the balance is
composed of lignin and polysaccharides.

Cellulose resins include four organic esters, cellulose
acetate (CA), cellulose acetate butyrate (CAB),
cellulose acetate propionate (CAP) and cellulose acetate
triacetate (CAT).
CORPORATE TRAINING AND PLANNING

In 1927, Eastman Kodak Co. commercialized
cellulose acetate into photographic film base.

Molding grade of CA was introduced in 1935.

In 1938, Eastman introduced CAB.

CAP was introduced in 1960.
CORPORATE TRAINING AND PLANNING
Polymerization

The cellulose esters are prepared by reacting
chemical cellulose with organic acids and anhydrides
using sulfuric acid as a catalyst.

In the standard synthesis of CA, the reaction
proceeds with acetic acid and acetic anhydride to the
triester stage. CA is prepared by hydrolyzing the
triester to remove some of its acetyl groups. Plastic
grade CA contains 38 to 40% acetyl.
CORPORATE TRAINING AND PLANNING

The propionate and butyrate esters are made by
substituting propionic acid and propionic anhydride
or butyric acid and butyric anhydride for some of the
acetic acid and acetic anhydride.

Plastic granules of CAP contain 39 to 47% propionyl
and 2 to 9% acetyl. CAB contains 26 to 39% butyryl
and 12 to 15% acetyl.
CORPORATE TRAINING AND PLANNING
When A is
and B is
Plastic is
H
Cellulose
H
—C—CH3
||
O
—C—CH3
||
O
—C—CH3
||
O
—C—CH2—CH3
||
O
Cellulose acetate
Cellulose acetate propionate
—C—CH3
||
O
—C—CH2—CH2—CH3
||
O
—C—CH2—CH3
||
O
—C—CH2—CH3
||
O
—CH2—CH3
—CH2—CH3
—NO2
—NO2
Cellulose acetate butyrate
Cellulose propionate
Ethyl cellulose
Cellulose Nitrate
CORPORATE TRAINING AND PLANNING
Cellulose Esters
Cellulose Acetate
Introduction

Manufacturing of cellulose acetate was done in 1865 using a
process in which cotton was heated with acetic anhydride in
sealed tube at 130-1400C but the process was difficult to
control.

With further research various new techniques
manufacturing of cellulose acetate are developed.
CORPORATE TRAINING AND PLANNING
of

One of the methods available today is homogenous
acetylation.

In this process cellulose is pretreated with glacial
acetic acid to open up the cellulosic matter.

After pretreating, acetylation is done by mixing
pretreated cellulose with acetylating agent like
acetic anhydride, a catalyst like concentrated
sulphuric acid and acetic acid as diluent.
CORPORATE TRAINING AND PLANNING
Properties
-
High water absorption
Poor electrical insulation characteristics
Limited aging resistance
Limited heat resistance
Dissolved by wide variety of reagents
CORPORATE TRAINING AND PLANNING
Properties of Cellulose acetate
Name
Specific gravity
Tensile Strength
Tensile modulus
Flexural modulus
Elongation at break
Impact Strength (Izod )
Hardness
HDT (under 1.82 MPa load.)
Melting point
Glass transition temperature
Dielectric Strength
Value
1.28
40
2174
1794
38
160
R62
61
240-260
157
13.4
Unit
-MPa
MPa
MPa
%
J/m
--°C
°C
°C
KV/mm
CORPORATE TRAINING AND PLANNING
Applications
CA Different applications
Spectacles
Tool handles
CORPORATE TRAINING AND PLANNING
Cellulose Acetate Butyrate (CAB)
Bleached Wood Pulp
Pretreated for 12 hours
+ 40-50% H2SO4
Drying with Acetic acid
Etherification of treated cellulose with mixture of Butyric acid
and acetic anhydride + H2SO4 ( Catalyst)
Cellulose acetate butyrate
CORPORATE TRAINING AND PLANNING
Properties
-
Good toughness
Excellent appearance
Giving good coating with hard glossy surface
Lower water absorption
Better flow properties
Lower density
CORPORATE TRAINING AND PLANNING
Properties of Cellulose Acetate
Butyrate
Name
Specific gravity
Tensile Strength
Tensile modulus
Value
1.19
34.5
1725
Unit
-MPa
MPa
Flexural modulus
Elongation at break
Impact Strength (Izod )
1449
50
187
MPa
%
J/m
Hardness
R75
---
HDT (under 1.82 MPa load.)
Dielectric Strength
65
13.4
°C
KV/mm
CORPORATE TRAINING AND PLANNING
Applications
Toys, tools handles, tabular keys, telephone
housing, pipes for conveying water, outdoor display
signs, vacuum formed products and protective
coating for metals.
CORPORATE TRAINING AND PLANNING
Cellulose Acetate Propionate
-
Cellulose Acetate Propionate having shorter side
chain and it is harder stiffer, and posses higher
tensile strength than Cellulose Acetate Butyrate.
-
Easy to vacuum form and also tend to be used for
applications like tool handles, safety lockers,
steering wheels, etc.
CORPORATE TRAINING AND PLANNING
Properties
Cellulose Acetate Propionate have shorter side
chain and it is harder, stiffer and possess higher tensile
strength than Cellulose Acetate Butyrate. Like
cellulose acetate butyrate, this is easy to vacuum form
and also tends to be used for applications like tool
handles, safety lockers, steering wheels, etc.
CORPORATE TRAINING AND PLANNING
Cellulose Nitrate
-
Cellulose Nitrate is manufactured by the
reaction between cellulose, nitric acid and
sulphuric acid.
-
It is possible to vary degree of etherification
according to the root hydroxyl group which is
replaced by nitrate group.
-
Fully nitrated cellulose, cellulose tri-nitriate
is an explosive.
-
Cellulose nitrate is precipiticised with
camphor in order to make it easy processable.
CORPORATE TRAINING AND PLANNING
Properties of Cellulose Nitrate

Good rigidity

Water white transparency

Poor chemical resistance

Reasonable toughness

Capable of forming highly attractive multi-coloured
sheeting

Highly inflammable.
CORPORATE TRAINING AND PLANNING
Applications

The one time important
photographic film.
application

Today the principal outlet are knife handles,table
tennis ball and spectacle frames.
CORPORATE TRAINING AND PLANNING
was
in