Bulk polymerization
Encyclopedia
Bulk polymerization or mass polymerization is carried out by adding a soluble initiator
to pure monomer
into liquid state.
Bulk polymerization
has several advantages over other methods, these advantages are :
Disadvantages :
Initiator
An initiator can refer to:* A person that takes an initiative in making something happen.* Modulated neutron initiator, a neutron source used in some nuclear weapons...
to pure monomer
Monomer
A monomer is an atom or a small molecule that may bind chemically to other monomers to form a polymer; the term "monomeric protein" may also be used to describe one of the proteins making up a multiprotein complex...
into liquid state.
Bulk polymerization
Polymerization
In polymer chemistry, polymerization is a process of reacting monomer molecules together in a chemical reaction to form three-dimensional networks or polymer chains...
has several advantages over other methods, these advantages are :
- The system is simple and requires thermal insulation.
- The polymerPolymerA polymer is a large molecule composed of repeating structural units. These subunits are typically connected by covalent chemical bonds...
is obtained pure. - Large castings may be prepared directly.
- Molecular weight distribution can be easily changed with the use of a chain transfer agent.
Disadvantages :
- Heat transfer and mixing become difficult as the viscosity of reaction mass increases.
- The problem of heat transfer is compounded by the highly exothermicExothermicIn thermodynamics, the term exothermic describes a process or reaction that releases energy from the system, usually in the form of heat, but also in the form of light , electricity , or sound...
nature of free radical addition polymerization. - The polymerization is obtained with a broad molecular weight distribution due to the high viscosityViscosityViscosity is a measure of the resistance of a fluid which is being deformed by either shear or tensile stress. In everyday terms , viscosity is "thickness" or "internal friction". Thus, water is "thin", having a lower viscosity, while honey is "thick", having a higher viscosity...
and lack of good heat transfer. - Very low molecular weights are obtained.