Organic Polymer Chemistry pptx

 Polymers from substituted derivatives of ethylene containing 2 times the original vinyliden name: poly + name substituted vinyliden  Functional group polymer: prefix poly then called

Organic Polymer

Chemistry

A polymer is a large molecule (macromolecule) composed of repeating basis monomer units

1811, Braconnot worked in derivative cellulose compounds-the earliest important work in polymer science

Development of vulcanization later in the nineteenth century

In 1907, Leo Baekeland created the first completely synthetic polymer

 Polymers from substituted derivatives of ethylene containing 2 times

the original vinyliden name: poly + name substituted vinyliden

 Functional group polymer: prefix poly then called functional group name

Example: polyester, polyamide, polyureth ane

Cl

Cl

Depend on different factors

Depend on origin: natural ( rubber, cellulose, protide,

…) and synthesis ( nylon, teflon,…)

Inorganic polymer: Main chain is form by inorganic elements

• Homopolymer: Homopolyme

as the polymer is formed

from a monomer

• Copolymer: Copolymers are

polymers formed from two or

more different monomers

 Depend on the component of the chain

Physical Property

 The most basic property of a polymer is the identity of its constituent monomers

 A second set of properties, known as microstructure,

essentially describe the arrangement of these monomers within the polymer

 Polymers have large molecule weight.

 Solutions of polymer have high viscosity

 Note: To know the physical property of polymer obviously, we must understand the phase behavior

 Is a polymer become a liquid when heated and hard when cooled.

 Can be easily remelted and moulded.

 Are high-molecule weight polymer.

 Chains are associated each other by Val der Wall

forces, dipole-dipole interation, hydrogen bonding.

 Remain many shapes.

 Can be branch or straight circuit.

 Some thermoplastic do not crystallize (form amorphous plastic)  less chemical resistant.

 Thermoplastic will crystallize to a certain extent (semi-crystalline)  more resistant to solvents and other chemicals.

When heated becoming harder

 Can not be remelted or remoulded

 Certain regular shape

 High hardness due to cross-link

 Almost hardness and brittle

stress

thermosetting Cross-link

Boiling point

 Tb strongly dependent on chain length

 High polymers do not exhibit a boiling point because they decompose before reaching theoretical boiling temperatures

 For shorter oligomers, Tb may be observed and will increase rapidly as chain length is increased

Glass transition temperature

 The temp at which polymers change from a crystalline solid to a

brittle, glassy amorphous solid-Tg

(1)- Crystalline material (2)-Polymer

• Critical length needed before strength increases.

• Hydrocarbon polymers average

of 100 repeating units necessary but only 40 for nylons.

• Tensile strength measures the forces needed to break a

polymer.

Chemical properties of polymer

 Reaction maintain polymer circuit

Polivinyl alcol PVA

 Reaction cuts polymer circuit

 Hydrolysis polyester

 Hydrolysis polypeptide or polyamide

 Pyrolysis polysterene

 Circuit connection reaction

 Vulcanization rubber  S S

 Bakelide resin

 A reaction in which many monomer units

combined into a large molecule

nA → –( A )n –

Polymerization

Free radical polymerization

 A reaction to form polymer from monomers that contain double bond (C=C)

Synthesis PMMA

 Is a clear plastic, used as a shatter proof replacement for glass

 PMMA is more transparent than glass

Reaction

Initiators: V59 -2,2'-Azodi(2-methylbutyronitrile )

Emulsion polymerization

 Latex is the stable dispersion (emulsion) of

polymer microparticles in an aqueous

evaporates, and therefore can form films

without releasing potentially toxic organic

solvents in the environment

 A monomer is dispersed or emulsified in a solution of surfactant and water forming relatively large droplets of monomer in water.

 Excess surfactant creates micelles in the water.

 Small amounts of monomer diffuse through the water to the

micelle.

 A water-soluble initiator is introduced into the water phase

where it reacts with monomer in the micelles

Theory

Mechanism

 Copolymerization is a polymerization

of two or many different monomers

 The reaction is useful for improving

properties of polymer with usage

purpose

Copolymerization of SBR

Limit: PS is stable with high temp but it is brittle and hardly dye.

Overcome: Decrease brittle property, we copolymerization Styrene with

Butadiene

Some examples about

condensation reactions

Zerol resin

axit ε-aminocaproic Nilon – 6 (capron silk)

Bakelide resin

Common characteristics

 Obtained polymers have high Ip factor (high dispersion).

 Can be branch off or three-directional.

 Contain functional groups at two sides of circuit.

 Two-direction condensation, three direction (more two functional groups).

 Homogeneous and un-homogeneous condensation (two type of

monomers soluble each other).

 Condensation between two types of monomers each other.

Basic type of reactions

 Forming co-products : reaction kind makes change molecular structure.

Reaction to form PET ( Polyethylene Terephthalate)

 Not forming co-products : not makes change molecular structure.

 Swell is process that solvent penetrates into polymers

 Two swell: critical swell, non critical swell

Factors affect to swell and

Condensation reaction occur

on the surface divided phase

 Monomers is not soluble each other

 Co-products escape and disperse into water environment.

 Polymer is selected directly from reaction medium.

 Occurring quickly, room temp.

Preparation between copolymer and

condensation reaction

Copolymer

 Concentration of monomers

reduce gradually during reaction.

 Polymers is established instantly

and Mw little change in reaction.

The longer reaction time spends,

the higher efficiency is obtained

 Components only contain

monomers, polymers.

 Products do not contain water.

 Need agent to create free

elements

Condensation

 Monomers do not maintain at first period of reaction.

 Mw increases with reaction time.

 Reaction need stretch.

 Components contain many types of different intermediate molecules.

 Products contain water.

 Do not need.

Block average molecule

Application of polymer

Application of Thermoplastics

Application of Elastomers

Application of Thermosets

Organic Polymer chemistry

Summary

Preparation methods

Applications Nonmenclature

Modern field in the

future

Characteristics

Physical properties

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