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Molecular Weight and its Influence on Polymer Properties, Schemes and Mind Maps of Programming Paradigms

The relationship between molecular weight and various properties of polymers. It explains how different molecular weight distributions affect polymer behavior, including melt viscosity, toughness, and strength. The document also discusses the role of intermolecular interactions in determining polymer properties, illustrating the concept with examples of different polymers like nylon-6, poly(vinylidene fluoride), and poly(acrylonitrile).

Typology: Schemes and Mind Maps

2024/2025

Uploaded on 03/19/2025

joanita-amoah
joanita-amoah 🇺🇸

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As the molecular weight of
Polyethylene increases the
melting point approaches the
theoretical asymptotic value of
145 C
Introduction Molecular Weight
1
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As^ the^ molecular^

weight^ of Polyethylene^ increases

the melting^ point^ approaches

the theoretical^ asymptotic

value^ of 145 C

Introduction^

Molecular Weight 1

•^ Even thought the polymer repeat unit is thesame, these molecular weight distributionsdescribe a polymer that behaves differently.•^ Green^ plot^ (top)

=^ low^ distribution

of

polymer molecular weight• Red^ plot^ (middle)^

=^ high^ distribution^ of

polymer molecular weight• Blue^ plot^ (bottom)^

=^ high^ distribution^ of Polymers^ polymer molecular weight with a additionalhigh molecular weight component

Molecular Weight

•^ A molecular weight distribution can be defined by a series of average values•^ Except Mp, these are various moments of the average of the molecularweights of the distribution•^ Mp is the molecular weight of the peak maxima•^ For any polydisperse peak:

Mn<Mw<Mz Polymers^

Molecular Weight

^ As the breadth of the distribution decreasesthe^ strength^ and^ toughness

of^ the^ polymer

increases ^ However as the breadth of the distributiondecreases the polymer becomes more difficultto process

SolubilityChemicalresistance MeltToughnessviscosity Strength

Increasing Mw+

Decreasing+distribution

Introduction^

Molecular Weight

Introduction^

Interactions between polymer chains

Introduction^

Interactions between polymer chains --++Nylon-^

-^ -  +^  Poly(vinylidene fluoride) Poly(acrylonitrile)

+- ^ 