A polymer’s molecular weight is the sum of the atomic weights of individual atoms that comprise a molecule. It indicates the average length of the bulk resin’s polymer chains. Not all polymer molecules of a particular grade have the exact same molecular weight. There is a range or distribution of molecular weights.
What does molecular weight depend on?
The weight average molecular weight depends not only on the number of molecules present, but also on the weight of each molecule.
What is a high molecular weight compound?
Simply stated, the ” high-molecular substances” as referred to by the Japan Industrial Standard mean ” substances with very high-molecular weights synthesized chemically.” Substances are classified into low-molecular, intermediate-molecular, and high-molecular substances according to their molecular weights.
Why is molecular weight important in chemistry?
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.
Which of the following will have highest molecular weight?
Answer: Polymer has the largest molar mass.
What are high molecular weight proteins?
Abstract. Many high-molecular-mass (HMM) proteins (MW>100 kDa) are known to be involved in cytoskeleton, defence and immunity, transcription and translation in higher eukaryotic organisms.
Does molecular weight change with temperature?
In a number of cases the molecular size parameters have been found to depend on the solution temperature. When observed, the temperature dependence can change molecular weight values by as much as 50%.
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.
How does molecular weight relate to the size of a molecule?
Molecular weight is the mass of an individual molecule, specifically the mass of material required to make a single mole. Molecular size relates to the physical size of an individual molecule. When used in light scattering techniques we refer to the ‘radius of gyration’ or Rg. Measurements are in nanometers.
Does viscosity increase with molecular weight?
A High molecular weight increases the viscosity of the material – makes it harder to process the material using conventional methods. The longer the chains, the harder it is to get them to flow because they are more tangled.
What is molecular weight range?
Most of the practically useful polymers have a DP between 200 to 2000, corresponding to a molecular weight range from 20,000 to 200,000.
Does mass affect boiling point?
In general, larger molecules have higher boiling points than smaller molecules of the same kind, indicating that dispersion forces increase with mass, number of electrons, number of atoms or some combination thereof.
What are the factors affecting the molecular weight of a polymer?
Some polymer properties that are very sensitive to the molecular weight include softening and melting point, glass transition temperature, solution and melt viscosity, solubility, mechanical strength and moduli.
How does molecular weight affect physical properties?
What is the difference between molecular mass and molecular weight?
The molecular mass (m) is the mass of a given molecule: it is measured in daltons (Da or u). Molecular weight, as a synonym of molar mass, is defined as the mass of a sample of that compound divided by the amount of substance in that sample, measured in moles (g/mol).
How do you reduce molecular weight?
Heating and shearing action is the clean way to reduce the molecular weight. You can also try by glycolysis method by heating with glycol or exposing to MW reactor. you will get reduced mol.
What is the meaning of low molecular weight?
Low Molecular Weight Heparin (LMWH), as its name suggests, is derived from Unfractionated Heparin (UFH) by digestion or depolymerization of longer chains of heparin into shorter chains by chemical or enzymatic means. These short strands make LMWH last longer and act more predictably in the body than UFH.
What is molecular weight explain with example?
The sum of the atomic masses of all atoms in a molecule, based on a scale in which the atomic masses of hydrogen, carbon, nitrogen, and oxygen are 1, 12, 14, and 16, respectively. For example, the molecular weight of water, which has two atoms of hydrogen and one atom of oxygen, is 18 (i.e., 2 + 16).
What are low molecular weight proteins?
Definition. Low molecular weight proteins (LMWP) are physiologically freely filtered by the glomerulus and reabsorbed by the intact proximal tubule. Serum concentrations of LMWP are more closely correlated with glomerular filtration rate than serum creatinine.
How do you separate high molecular weight proteins?
Proteins can travel faster through a gel that contains a lower percentage of polyacrylamide. Hence a low-density polyacrylamide gel would be able to separate proteins that are close in molecular weight with higher resolution.
Is albumin high or low molecular weight protein?
The low molecular weight (LMW) serum proteome is that protein/peptide fraction from which high molecular weight proteins, such as albumin, immunoglobulins, transferrin, and lipoproteins, have been removed.
How does temperature affect molecular mass?
The speed of the molecules in a gas is proportional to the temperature and is inversely proportional to molar mass of the gas. In other words, as the temperature of a sample of gas is increased, the molecules speed up and the root mean square molecular speed increases as a result.
How does pressure affect molar mass?
So pressure is proportional to the number of moles of gas, not the mass of the gas. If you replace a given gas with one with double the molecular weight, for n to be the same, the mass of the replacement gas has to be double the mass. Yet the pressure is the same. Pressure is not dependent on mass.
How does molecular mass affect the state of matter?
The molar mass of an element or compound has a lot to do with determining its possible state of matter (solid, liquid, gas) generally as the molar mass of a substance increases then it gets more and more dense. As the density increases it is more likely to be in the solid state.
How does molecular weight affect tensile strength?
A higher molecular weight also means that there is more increased chain entanglement. This bring about an increase in tensile strength and elastic modulus due to the fact that more energy is required to break or loosen the entangled chains.