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

Download Molecular Weight and its Influence on Polymer Properties and more Schemes and Mind Maps Programming Paradigms in PDF only on Docsity!

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)

+- ^ 