Cellulose Plastics Cellulose Plastics Introduction Cellulose natural is

Cellulose Plastics

Cellulose Plastics Introduction Ø Cellulose natural is a polymer produced from wood via wood pulp. Ø Woven grade cotton contains about 90% cellulose while an average wood has about 50% and the balance is composed of lignin and polysaccharides. Ø acetate (CA), cellulose acetate butyrate (CAB), cellulose acetate propionate (CAP) and cellulose acetate triacetate (CAT).

Ø In 1927, Eastman Kodak Co. commercialized cellulose acetate into photographic film base. Ø Molding grade of CA was introduced in 1935. Ø In 1938, Eastman introduced CAB. Ø CAP was introduced in 1960.

Polymerization cellulose The 1. prepared esters are reacting by chemical cellulose with organic acids and anhydrides using sulfuric acid as a catalyst. 2. 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.

Ø 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 Ø granules CAP ofcontain 47% to 39 propionyl and 2 to 9% acetyl. CAB contains 26 to 39% butyryl and 12 to 15% acetyl.

When A is and B is Plastic is H H Cellulose —C—CH 3 Cellulose acetate || || O O —C—CH 3 —C—CH 2—CH 3 Cellulose acetate propionate || || O O —C—CH 3 —C—CH 2—CH 3 Cellulose acetate butyrate || || O O —C—CH 2—CH 3 —C—CH 2—CH 3 Cellulose propionate || || O O —CH 2—CH 3 —CH 2—CH 3 Ethyl cellulose —NO 2 Cellulose Nitrate

Cellulose Esters Cellulose Acetate Introduction Ø Manufacturing cellulose of acetate was done 1865 in using a process in which cotton was heated with acetic anhydride in sealed tube at 130 -1400 C but the process was difficult to control. Ø manufacturing of cellulose acetate are developed.

1. 2. 3. homogenous acetylation. acetic acid to open up the cellulosic matter. pretreated cellulose with acetylating agent like acetic anhydride, a catalyst like concentrated sulphuric acid and acetic acid as diluent.

Properties - High water absorption Poor electrical insulation characteristics Limited aging resistance Limited heat resistance Dissolved by wide variety of reagents

Properties of Cellulose acetate Name Specific gravity Tensile Strength Tensile modulus Value 1. 28 40 2174 Unit -MPa Flexural modulus Elongation at break Impact Strength (Izod ) Hardness HDT (under 1. 82 MPa load. ) Melting point Glass transition temperature Dielectric Strength 1794 38 160 R 62 61 240 -260 157 13. 4 MPa % J/m --°C °C °C KV/mm

Applications CA Different applications Spectacles Tool handles

Cellulose Acetate Butyrate (CAB) Bleached Wood Pulp + 40 -50% H 2 SO 4 Pretreated for 12 hours Drying with Acetic acid Etherification of treated cellulose with mixture of Butyric acid and acetic anhydride + H 2 SO 4 ( Catalyst) Cellulose acetate butyrate

Properties - Good toughness Excellent appearance Giving good coating with hard glossy surface Lower water absorption Better flow properties Lower density

Properties of Cellulose Acetate Butyrate Name Specific gravity Tensile Strength Tensile modulus Value 1. 19 34. 5 1725 Unit -MPa Flexural modulus Elongation at break Impact Strength (Izod ) Hardness HDT (under 1. 82 MPa load. ) Dielectric Strength 1449 50 187 R 75 65 13. 4 MPa % J/m --°C KV/mm

Applications Toys, tools handles, tabular keys, telephone housing, pipes for conveying water, outdoor display signs, vacuum formed products and protective coating for metals.

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.

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.

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.

Properties of Cellulose Nitrate Ø Good rigidity Ø Water white transparency Ø Poor chemical resistance Ø Reasonable toughness Ø Capable of forming highly attractive multi-coloured sheeting Ø Highly inflammable.

Applications Ø Ø photographic film. tennis ball and spectacle frames.