initiator, a source of any chemical species that reacts with a monomer (single molecule that can form chemical bonds) to form an intermediate compound capable of linking successively with a large number of other monomers into a polymeric compound.
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What is the reason of adding initiator is more important?
The addition of initiator is important because towards the end of the polymerization the degree of dilution of the monomer is extremely high, and therefore, the efficiency of the initiator is very low. In some cases, it is lost by chain transfer with the solvent or by mutual destruction of the radicals.
How does initiator concentration affect molecular weight?
Intrinsic Viscosity and Molecular Weight The higher initiator concentration leads to a 23% decrease in molecular weight.
What is the role of initiator in free radical polymerization?
Initiation of Free Radical Initiation is the foremost step in the polymerization process. An active centre is generated in this process to begin polymerization. All the monomers are not liable for the initiation process. One or two radicals are created from the initiating molecules in the first step.
What is the difference between initiator and inhibitor?
If the radical reacts with another radical to give something that is no longer capable of propagating the radical reaction, it is an inhibitor. If it reacts to give more radicals it is an initiator.
What is the difference between an initiator and a catalyst?
Initiators trigger chemical reactions. They are not true catalysts, as they become an integral part of the end product; because of this they are instead considered to be co-reactants. Reaction accelerators are catalysts which quicken the progress of a chemical reaction.
Why initiator is used for polymerization?
Initiators are often used in chain-growth polymerization such as radical polymerization to regulate initiation by heat or light. Thermal polymerization initiators are compounds that generate radicals or cations upon exposure to heat.
How can you be an effective initiator?
Good initiators have to be willing – and ready – to fail because they will. This may be one of the hardest skills to exercise. There will be times when they will boldly proclaim a new idea and outline a plan and it doesn’t work. Initiators are not in the business of fixing things.
What is initiator efficiency?
Initiator efficiency f is defined as the fraction of primary (initiator-derived) free-radical species that add to monomer molecules. The reported data refer to ideal CSTR mixing conditions.
How do you select the initiator for polymerization?
How does one choose the appropriate initiator? In a free radical addition polymerization, the choice of polymerization initiator depends mainly on two factors: a) its solubility and b) its decomposition temperature.
Does concentration affect molecular weight?
However, more concentration of initiator or catalyst (as in coordination polymerization) will cause more chains to grow which will give lower molecular weight.
How do you increase the molecular weight of free radical polymerization?
- Increase the amount of initiator relative to monomer (i.e. double or triple the amount).
- Use a chain transfer agent such as a thiol or mercaptan (R-S-H).
What makes a good radical initiator?
Ideally, a thermal free radical initiator should be relatively stable at room temperature but should decompose rapidly enough at the polymer-processing temperature to ensure a practical reaction rate.
How do radical initiators work?
In chemistry, radical initiators are substances that can produce radical species under mild conditions and promote radical reactions. These substances generally possess weak bonds—bonds that have small bond dissociation energies. Radical initiators are utilized in industrial processes such as polymer synthesis.
What is the initiator in free radical mechanism?
Free radical mechanism: In this, alkenes and its derivatives are polymerized in the presence of a free radical generating initiator like benzoyl peroxide and tert-butyl peroxide. Like, the polymerisation of ethene to polythene occurs by heating a mixture of ethene with a small amount of benzoyl peroxide initiator.
How can inhibitors affect polymerization?
Monomers are often stabilized by the addition of inhibitors to prevent polymerization initiation by light, heat and air. For example, stable radical compounds which can trap free radicals are used to inhibit radical polymerization.
What is initiator storage?
Initiator – An initiator is the consumer of storage, typically a server with an adapter card in it called a Host Bus Adapter (HBA). The initiator “initiates” a connection over the fabric to one or more ports on your storage system which are called target ports.
What does initiator do in Valorant?
Initiators are one of the four roles that agents are divided into in VALORANT. The abilities of agents under this role focus on flushing enemies out of hiding spots and corners in order to assist the team when charging into battle. The game currently has five Initiator agents in its roster.
Are the good initiators for free radical chain polymerization?
For free radical chain polymerization benzoyl peroxide and hydrogen peroxide are the good initiators.
How do you choose a catalyst for a reaction?
The criteria of selecting catalysts for these reactions have been formulated; 1) fast heterolytic activation of C−H bonds; 2) relatively slow primary activation of oxygen; 3) fast diffusion of oxygen vacancies; 4) fast electron transfer from the adsorbed substrate to catalyst.
What are two important variables in the formation of polymers?
5.4. Polymerization temperature and catalyst level are the two most important polymerization variables. Molecular weight is slightly influenced by catalyst concentration. This behavior is characteristic of polymerizations by heterogeneous catalysts.
Which type of initiator is used in cationic polymerization?
The Initiator most often used in cationic polymerization is a lewis acid.
Which of the following is NOT initiator in the radical polymerization?
Solution : Answer(4) `(C_6H_5CO)_2 O_2` is not used as an initiator in ionic polymerisation. Step by step solution by experts to help you in doubt clearance & scoring excellent marks in exams.
Is an initiator a leader?
An Initiator is a person that takes an initiative in making something happen, a Leader is somebody whom people follow. The Initiator dose not always needs a approval and may simply start his work.
What structure is identified with a hybrid of the two structures that caters the function and division Brainly?
A matrix structure is a hybrid of the functional and divisional structures.