The lower the molecular weight, lower the transition temperature, viscosity , and the mechanical properties. Due to increased entanglement of chains with increased molecular weight, the polymer gets higher viscosity in molten state, which makes the processing of polymer difficult.
Why is the molecular weight of a polymer so important?
A High molecular weight increases the impact resistance of the material . The higher degree of entanglement means that in order to rupture, more polymer bonds need to be broken, this means that the polymer can absorb more energy before failing. A High molecular weight increases the chemical resistance – to a point.
How will increased molecular weight affect the modulus of a polymer sample?
Molecular weight has an important effect on the mechanical properties of polymer, more especially above the glass transition temperature . Indeed, glass transition increases with the molecular weight as it does the storage modulus. At large deformations (above Tg), the mechanical strength and deform ability are higher.
What is molecular weight applied to a polymer?
Polymer molecular weight is the molecular mass of a polymer chain. It can be obtained by multiplying the mass of each repeating unit (M 0 ) by the degree of polymerisation and then adding the mass of end groups . For a linear polymer, it is rare that all polymer chains have the same mass.
Why different average molecular weight are considered for polymer?
The molecular weight of a synthetic polymer does not have a single value, since different chains will have different lengths and different numbers of side branches . There will therefore be a distribution of molecular weights, so it is common to calculate the average molecular weight of the polymer.
Are ceramics stronger than polymers?
Ceramics are brittle, strong and non-conducting materials. Ceramics are typically compounds consisting of metals covalently bonded to oxygen, nitrogen or carbon. ... Polymers are usually carbon based. Polyethylene is a long chain of carbons bonded together in a straight line.
How do you increase the molecular weight of a polymer?
A High molecular weight increases the impact resistance of the material . The higher degree of entanglement means that in order to rupture, more polymer bonds need to be broken, this means that the polymer can absorb more energy before failing. A High molecular weight increases the chemical resistance – to a point.
Can molecular weight change?
The changes in molecular weight of a long-chain polymer (initially of arbitrary molecular-weight distribution) are studied when the main chain is subjected to random fracture, such as occurs when certain polymers are exposed to high-energy radiation.
What are the two categories of polymers?
- thermosetting plastic or thermoset.
- thermoforming plastic or thermoplastic.
What is molecular weight used for?
Molecular weight is a measure of the sum of the atomic weight values of the atoms in a molecule . Molecular weight is used in chemistry to determine stoichiometry in chemical reactions and equations. Molecular weight is commonly abbreviated by M.W. or MW.
Do polymers have high molecular weight?
A High molecular weight increases the impact resistance of the material . The higher degree of entanglement means that in order to rupture, more polymer bonds need to be broken, this means that the polymer can absorb more energy before failing. A High molecular weight increases the chemical resistance – to a point.
What is the average weight and molecular mass of polymers?
| Number of Molecules Mass of each Molecule | 3 750,000 | 5 700,000 | 8 650,000 | 10 600,000 |
|---|
What are the different types of molecular weight of polymers?
Molecular weight of polymers: Regarding the molecular weight of a polymer, we will discuss three types of molecular weight- Number average Molecular weight (Mn), Weight average molecular weight (Mw) and viscosity average molecular weight (Mv) .
Is Metal tougher than ceramic?
Ceramics tend to be much harder than commonly used metals . It means that they have higher wear resistance and are widely used as abrasion resistant materials.
Where are polymers found?
Polymers are both found in nature and manufactured in laboratories . Natural polymers were used for their chemical properties long before they were understood in the chemistry laboratory: Wool, leather, and flax were processed into fibers to make clothing; animal bone was boiled down to make glues.
Are polymers ceramic?
Although ceramic is an inorganic material like polymer, ceramic is made up of naturally occurring substances and is one of the oldest building and crafting materials known to man. ... For crafting purposes, polymer comes in clay form. Although it is called “polymer clay,” there is no actual clay in the material.
