ldpe bags - pharma grade

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    LDPE

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    What is LDPE ?

    Low-density polyethylene(LDPE) is

    a thermoplasticmade from

    the monomerethene.

    http://en.wikipedia.org/wiki/Thermoplastichttp://en.wikipedia.org/wiki/Monomerhttp://en.wikipedia.org/wiki/Ethylenehttp://en.wikipedia.org/wiki/Ethylenehttp://en.wikipedia.org/wiki/Monomerhttp://en.wikipedia.org/wiki/Thermoplastic
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    What is a Polymer ?

    The macromolecular that are formed bycombination of one or more than two types ofinnumerable simple molecules by chemical bondformation are called Polymers.

    One or more than two type of innumerablesimple organic molecules that combine with oneanother & form a polymer are called monomers.

    The reaction process of one or more than two

    innumerable simple organic molecules thatcombine with each other by Chemical bondformation is called Polymerisation

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    Types of Polymer Substance

    Polymer substance are classified in different types.

    Naturally occurring Polymer Substances- The polymers obtainedfrom nature (plants and animals) are called natural polymers. Thesepolymers are very essential for life. For e.g.: Cellulose, Proteins,

    Starch, Nucleic acid- DNA & RNA Semisynthetic Polymer Substances-Semisynthetic Polymer are

    obtained by chemical reaction with Polymeric substance occurringin nature. The rubber with improved properties obtained byvulcanization of natural rubber is used in the formation of tyres.

    Synthetic Polymer Substance -The polymers which are prepared inthe laboratories are called synthetic polymers. These are also calledman made polymers. For e.g.: polyethene, PVC nylon, teflon,bakelite terylene, synthetic rubber etc.

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    Classification of Polymers

    HOMOPOLYMER & CO-POLYMER

    Homopolymers: These consist of chains with

    identical bonding linkages to each monomer

    unit. These may be represented as: -[A-A-A-A]-

    Copolymer : These consist of chains with two

    or more linkages usually implying two or more

    different type of monomer units. Thes may be

    respresented as:-[A-B-A-B-A-B]-

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    Polymer Classified by mode of

    Polymerzation

    Addition Polymers: The monomer molecules

    bond to each other without the loss of any

    other atoms.

    Eg : Ethylene--- CH2=CH2 ----->~~CH2-CH2-CH2-CH2~~ Polyethylene (PE)

    Condensation Polymers: Usually two different

    monomer combine with the loss of a small

    molecule, usually water.

    Eg :

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    Thermoplastics.

    Thermosets.

    Elastomers.

    Classification of Polymers

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    Low-density polyethylene(LDPE) is

    a thermoplasticmade from

    the monomerethene.

    Structure

    http://en.wikipedia.org/wiki/Thermoplastichttp://en.wikipedia.org/wiki/Monomerhttp://en.wikipedia.org/wiki/Ethylenehttp://en.wikipedia.org/wiki/Ethylenehttp://en.wikipedia.org/wiki/Monomerhttp://en.wikipedia.org/wiki/Thermoplastic
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    Types of Polyethene

    Low Density Polyethylene (LDPE)

    Linear Low Density Polyethylene

    (LLDPE)

    Medium Density Polyethylene

    (MDPE) High Density Polyethylene (HDPE,

    aka HD)

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    Properties of LDPE

    MECHANICAL PROPERTIES OF LDPE

    It has more open structuredue to presence of a small amount ofbranching in the chain (on about 2% of the carbon molecule).

    It is translucent to opaque, strong, tough & enough to be virtuallyunbreakableand at the same time quite flexible.

    CHEMICAL PROPERTIES

    Chemically LDPE is uncreative at room temperature, slowly attackedby strong oxidizing agents and some solvents will cause softening orswelling.

    It may be used at temperatures up to 95 Celsius for short periodsand at 80 Celsius continuously.

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    Surface Property Modifiers

    Sleep & Blocking AgentPrevent film & sheet sticky

    Anti Static AgentPrevent static charges on surface

    Anti Fogging AgentDisperse moisture droplets on film

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    Aesthetic property

    Dyes and pigments - impart color

    Odorants - add fragrance

    Deodorants - prevent development of odor

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    Other LDPE Properties

    Films are soft and clear

    Good for heat-sealing

    Fair moisture barrier, very poor oxygen barrier.

    Very high elongation (desirable for stretch wrap) Translucent, very tough, weatherproof, good chemical

    resistance, low water absorption.

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    Plastic Polymer Additives

    Process stabilizers (heat stabilizers)

    Environmental stabilizers (anti-oxidants, UV

    stabilizers)

    Surface modifiers (anti-static, anti-blocking)

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    Applications of LDPE

    Agriculturefor protection of delicate crops fromextreme weather conditions.

    Lining of Canal, reservoir, ponds from leakage loss.

    Packaging and wrapping. Water roofing for terrace gardens.

    For protection of food grains, fertilizers, cotton,chemicals, cement, constructions etc.

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    Testing Procedure of LDPE Bags

    A tensile test, also known as tension test and it is

    most fundamental type of mechanical test which can

    perform on material.

    By pulling on something, very quickly determine howthe material will react to forces being applied in

    tension. As the material is being pulled, one can find

    its strength and stretch.

    http://www.instron.in/wa/resourcecenter/glossaryterm.aspx?ID=164http://www.instron.in/wa/resourcecenter/glossaryterm.aspx?ID=164
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    Tear Strength Test (Tear Testers)

    Tear testing is a measurement of the resistance of sheet typematerials to tearing. A common approach is to apply a tension loadto a sample that has been prepared with a cut to begin thecontrolled tear.

    Dart Impact Test

    Falling dart impact is a traditional method for evaluating the impactstrength or toughness of a plastic film. This test uses a single dartconfiguration and a single drop height, while change the weight ofthe dart. Test results can be used either as a quality controlevaluation or for end use comparisons.

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    Recycling

    After individuals drop LDPE products off

    at a recycling center, the recycling company

    melts the plastic to eliminate contaminants.

    After putting the low density polyethylene

    under heat, the material is fashioned into thin

    plastic sheets, which the recycling company

    then sells to manufacturers.

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    Recycling Code

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    Comparison

    16%

    76%

    0%11%

    Film Applications

    HDPE

    LDPE/LLDPE

    PP

    PVC

    As per the Saltors Advanced Chemistry 2000

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    Thank You