What kind of reaction is called polymerization reaction?
Polymerization reactions are chain reactions, and the formation of Teflon from tetrafluoroethylene is one example. In this reaction, a peroxide (a compound in which two oxygen atoms are joined together by a single covalent bond) may be used as the initiator.
What are the two types of polymerization reactions?
There are two general types of polymerization reactions: addition polymerization and condensation polymerization. In addition polymerization, the monomers add to one another in such a way that the polymer contains all the atoms of the starting monomers. Ethylene molecules are joined together in long chains.
Is polymerization a chemical reaction?
In polymer chemistry, polymerization (American English), or polymerisation (British English), is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks. There are many forms of polymerization and different systems exist to categorize them.
What is difference between polymerization and condensation?
The main difference between addition and condensation polymerization is that in addition polymerization the polymers are formed by the addition of monomers with no by-products whereas in condensation polymerization, the polymers are formed due to the condensation more than one different monomers resulting in the …
Which polymerization is faster?
A key characteristic of living polymerization is that the rate of initiation (meaning the dormant chemical species generates the active chain propagating species) is much faster than the rate of chain propagation. Thus all of the chains grow at the same rate (the rate of propagation).
What are the polymerization techniques?
Polymerization techniques
- POLYMERIZATI ON TECHNIQUES.
- POLYMERIZATION TECHNIQUES 1.
- BULK POLYMERIZATION • Mass or block polymerization: Polymerization of the undiluted monomer.
- BULK POLYMERIZATION • The method is used for the polymerization of liquid state monomers.
- Advantages Disadvantages • The system is simple and requires thermal insulation.
Is formed by addition polymerization?
An addition polymer is a polymer formed by chain addition reactions between monomers that contain a double bond. Molecules of ethene can polymerize with each other under the right conditions to form the polymer called polyethylene.
What things can we do to make a cationic polymerization controlled?
There are a variety of initiators available for cationic polymerization, and some of them require a coinitiator to generate the needed cationic species.
- Classical protic acids.
- Lewis acids/Friedel-Crafts catalysts.
- Carbenium ion salts.
- Ionizing radiation.
- Effect of temperature.
- Effect of solvent and counterion.
What is chain transfer reaction?
Chain transfer is a polymerization reaction by which the activity of a growing polymer chain is transferred to another molecule. P• + XR’ → PX + R’• Chain transfer reactions reduce the average molecular weight of the final polymer.
Why is polymer added to water?
A polymer is a very large organic molecule; it is a chain of monomer subunits. In wastewater treatment processes, polymers are used to coagulate suspended solids and produce large curds of solid materials (floc).
What is the mechanism of coordination polymerization?
2.2. In coordination polymerization the monomers with side groups are attached to the growing chain in a highly defined spatial arrangement (stereoregular). The significant feature of this mechanism is the ability to orient each monomer and join it to the growing polymer chain in a very specific configuration.
Which catalyst is used in coordination polymerization explain?
12.3. 2 Polymerisation stereochemistry of high density polyethylene (HDPE) HDPE is produced by coordination polymerisation using a catalyst, usually Ziegler-Natta (ZN). This controls the combining of the monomer, polymerisation taking place on the catalyst’s surface.
What is the difference between solution polymerization and emulsion polymerization?
At the end, the emulsion latex particle is in fact an oil in water emulsion when aqueous. In solution polymerization, a processor dissolves a monomer in a suitable solvent, along with chain transfer agents and a free radical initiator.
What is the difference between emulsion and suspension polymerization?
The two differences between emulsion and suspension polymerization are: 1) that a suspension polymerization is a mechanical process, and must have a stabilizing agent until the droplets are far apart, and 2) the emulsion polymerization is a chemical process which requires a surfactant to make the monomer “emulsify.”
What are the advantages of emulsion?
The advantages of emulsion polymerization are that its use permits a rapid polymerization to a high molecular weight with narrow molecule weight distribution, the viscosity is typically lower than other methods, heat is relatively easy to remove from the reactor with water as the continuous phase and suitable for the …
What is difference between suspension and emulsion?
A few factors that can help differentiate between suspension and emulsion are: Phases: In a suspension, you can find two substances of any phase of matter like solid, liquid, and gas. At the same time, an emulsion consists of only two immiscible liquids. On the other hand, emulsions have two liquid phase particles.
How is bulk polymerization carried?
Bulk polymerization or mass polymerization is carried out by adding a soluble radical initiator to pure monomer in liquid state. The initiator should dissolve in the monomer. The reaction is initiated by heating or exposing to radiation. As the reaction proceeds the mixture becomes more viscous.
What is the difference between bulk and solution polymerization?
Solution polymerization occur in existence of inert solvent and suitable catalyst, on the contrary of bulk polymerization which doesn’t need any additives just monomer and a suitable initiator, which has two types batch and continuous bulk polymerization.
What are the two different criteria of polymer solubility?
Solubility depends on the nature of the solvent, the temperature of the solution, the topology of the polymer, and the crystallinity.
What is Pearl polymerization?
Suspension polymerization, sometimes called bead, pearl or granular polymerization, is one of the most widely used polymerization techniques. It is essentially a water or solvent cooled bulk polymerization, though water/solvent soluble initiators may be present that could alter the reaction kinetic.
How does interfacial polymerization work?
Interfacial polymerization is a type of step-growth polymerization in which polymerization occurs at the interface between two immiscible phases (generally two liquids), resulting in a polymer that is constrained to the interface.
How does emulsion polymerization work?
Emulsion polymerization is a polymerization process with different applications on the industrial and academic scale. It involves application of emulsifier to emulsify hydrophobic polymers through aqueous phase by amphipathic emulsifier, then generation of free radicals with either a water or oil soluble initiators.
What are the advantages of suspension polymerization?
The main advantages of suspension polymerization over emulsion systems are that no surfactants, which are difficult to remove from the product, are used, and no ionic end groups are present, which may be unstable during processing at high temperatures.
How many phases does the suspension have?
two phases
Which of the following can be produced using suspension polymerization?
Which of the following can be produced using suspension polymerisation? Explanation: The poly methyl methacrylate, polyvinyl chloride and high impact polystyrene can be produced by using the suspension polymerisation.
Which one of the following can’t be used as protective colloid in emulsion or suspension polymerization?
Which of the following cannot be a protective colloid for emulsion polymerization? Explanation: The water soluble polymers like carboxy-methyl cellulose, PVA and gelatin stabilizes the emulsion and prevents emulsion break down with progress of polymerization, so these can be called as a protective colloid for emulsion.