Biopolymer.ppt 385ww

Bio-Based Polymer Development Lecture-5

Applications 

Coatings  Fibers  Plastics  Adhesives  Cosmetics  Oil Industry  Paper  Textiles/clothing  Water treatment  Biomedical  Pharmaceutical  Automotive  Rubber

Polymers  Polymers

are broadly classified into:

 Synthetic  Natural

 Synthetic

polymers are obtained via polymerization of petroleum-based raw materials through engineered industrial processes using catalysts and heat

Synthetic Polymers 

Polyethylene  Polypropylene  Polytetrafluoroethylene (Teflon®)  Polyvinylchloride  Polyvinylidenechloride  Polystyrene  Polyvinylacetate  Polymethylmethacrylate (Plexiglas®)  Polyacrylonitrile



Polybutadiene  Polyisoprene  Polycarbonate  Polyester  Polyamide (nylons)  Polyurethane  Polyimide  Polyureas  Polysiloxanes  Polysilanes  Polyethers

Natural Polymers  Natural

polymeric materials have been used throughout history for clothing, decoration, shelter, tools, weapons, and writing materials  Examples of natural polymers:  Starch

 Cellulose

(wood)

 Protein  Hair  Silk  DNA

and RNA

 Horn  Rubber

Biopolymers  Biopolymers

are obtained via polymerization of biobased raw materials through engineered industrial processes (Poly-lactic acid, polylactones etc)

 The

raw materials of biopolymers are either isolated from plants and animals or synthesized from biomass using enzymes/ microorganisms (Chitin, chitosan, alginates, carrageenan, starch, cellulose)

Examples of Biopolymers  Polyesters 



Polylactic acid Polyhydroxyalkanoates

 Proteins   

Silk Soy protein Corn protein (zein)

 Polysaccharides   

 

Xanthan Gellan Cellulose Starch Chitin

 Polyphenols 

 

Lignin Tannin Humic acid

 Lipids 



Waxes Surfactants

 Specialty   

polymers

Shellac Natural rubber Nylon (from castor oil)

Why Biopolymers? 

Fossil fuels (oil, gas, coal) are in finite supply and alternative renewable sources of raw materials are needed



Most synthetic polymers are not biodegradable

Where are Biopolymer Polymers Needed?  Packaging

materials (e.g., trash bags, loosefill foam, food containers)  Consumer goods (e.g., egg cartons, razor handles, toys)  Medical applications (e.g., drug delivery systems, sutures, bandages, orthopedic implants)  Cosmetics  Coatings  Hygiene products

Classification of Natural bio polymers (Based on Origin)

Plant Polysaccharides Eg: Cellulose, Starch, Alginate

Animal Protein s Eg: Collage n (Gelati n), Albumi n

Polysaccha rides Eg: Chitin (Chitosan), Hyaluronat e

Microbes Polyester s Eg: Poly(3hydroxyla lkonate)

Polysacchar ides Eg: Hyaluronate

Poly(e-caprolactone)  As

early as 1973, it was shown that poly(e-caprolactone) degrades in bioactive environments such as soil O

[ O (CH2)5 C ] n

 Poly(e-caprolactone)

and related polyesters are water resistant and can be melt-extruded into sheets and bottles

Polyhydroxyalkanoates  Polyhydroxyalkanoates

(PHA) accumulate as granules within cell cytoplasm O H [O C

O (CH2)n C ] OH

 PHAs

are thermoplastic polyesters with TM m.p. 50–180ºC (Biopol )

 Properties

can be tailored to resemble elastic rubber (long side chains) or hard crystalline plastic (short side chains)

Starch  Starch

is the principal carbohydrate storage product of plants

 Starch

is extracted primarily from corn; with lesser sources being potatoes, rice, barley, sorghum, and wheat

 All

starches are mixtures of two glucan polymers – amylose and amylopectin, at ratios that vary with the source

Starch (continued)  ~75%

of industrial corn starch is made into adhesives for use in the paper industry

 Corn

starch absorbs up to 1,000 times its weight in moisture and is used in diapers (>200 million lb annually)

 Starch-plastic

blends are used in packaging and garbage bag applications

U.S. Congress, Office of Technology Assessment, Biopolymers: Making Materials Nature’s Way-Background Paper, OTABP-E-102 (Washington, DC: U.S. Government Printing Office, September 1993

Starch structure

Starch (continued)  Starch

blended or grafted with biodegradable polymers such as polycaprolactone are available in the form of films  Blends with more than 85% starch are used as foams in lieu of polystyrene

Cellulose 

Cotton contains 90% cellulose while wood contains 50% cellulose



Cellulose derivatives are employed in a variety of applications RO

ROH 2C

OR

O RO

O n R

O O RO



OR ROH 2C

Carboxymethyl cellulose is used in coatings, detergents, food, toothpaste, adhesives, and cosmetics applications

Cellulose Structure

Cellulose (continued)  Hydroxyethyl

cellulose and its derivatives are used as thickeners in coatings and drilling fluids

 Methyl

cellulose is used in foods, adhesives, and cosmetics

 Cellulose

acetate is a plastic employed in packaging, fabrics, and pressure-sensitive tapes

Methyl cellulose

Cellulose acetate

Lactic Acid  Lactic

acid is produced principally via microbial fermentation of sugar feedstocks OH CH3

CH COOH

 Variation

in polymerization conditions and L- to D- isomer ratios permit the synthesis of various grades of polylactic acid

 Polylactide

polymers are the most widely used biodegradable polyesters

Polylactic Acid  Polylactic

acid (PLA) degrades primarily by hydrolysis and not microbial attack

 PLA

fabrics have a silky feel and good moisture management properties (draws moisture away and keeps the wearer comfortable)

 Copolymers

of lactic acid and glycolic acid are used in sutures, controlled drug release, and as prostheses in orthopedic surgery

Polylactic acid

Polyvinyl Alcohol  Polyvinyl

alcohol is the only polymer with exclusively carbon atoms in the main chain that is regarded as biodegradable OH CH2

 Polyvinyl

CH

n

alcohol is used in textile, paper, and packaging industries

Chitin & Chitosan

Chitin vs Chitosan 

 

Chitin is a macromolecule found in the shells of crabs, lobsters, shrimps and insects Chitosan is obtained by partial deacetylation of chitin. Chitin is insoluble in its native form but chitosan, the partly deacetylated form, is water soluble.

Chitin

Chitin structure

Chitin, a polysaccharide, is almost as common as cellulose in nature, and is an important structural component of the exoskeleton of insects and shellfish

Chitin 

Chitin, a polysaccharide, is almost as common as cellulose in nature, and is an important structural component of the exoskeleton of insects and shellfish CH2OH

NHCOCH3

O HO

CH2OH O

O

O

OH

O HO

NHCOCH3

CH2OH

n

OH NHCOCH3



Chitin and its derivative, chitosan, possess high strength, biodegradability, and nontoxicity



The principal source of chitin is shellfish waste

Chitosan

Chitosan Application  Chitosan

forms a tough, water-absorbent, oxygen permeable, biocompatible films, and is used in bandages and sutures

 Chitosan

is used in cosmetics and for drug delivery in cancer chemotherapy

 Chitosan

carries a positive charge (cationic) in aqueous solution and is used as a flocculating agent to purify drinking water

Chemistry 

linear co-polymer of β(1-4) linked glucosamine and N-acetyl-Dglucosamine.

Deacetylated chitin to chitosan

Decalcification-Dilute HCL Deproteination-Dilute NaOH Decolorization- 0.5 % KMno4 & Oxalic acid. DeacetylationHot Conc. NaOH ( 40-50 %)

Extraction Chitin to chitosan Crustacean shells (containing chitin)

Dil. NaOH

Dil. HCl

Deproteiniza tion

Demineralization 0.5% KMnO4 and oxalic acid

Deacetylation (chitosan)

Hot Conc. NaOH (4050%)

De colorization