Question

Which of the following polymers can be made by a free radical addition polymerization mechanism?
A. PE
B. HDPE
C. LDPE
D. Teflon

Answer 1

We have to remember that the polymer is made by individual small molecules, known as monomers (single part) and the monomers are linked to produce a macromolecule, this process is called polymerization. The addition of free-radical to an active chain-end regenerates the active site at the chain-end is called the free-radical polymerization. Free radical polymerizations are chain reactions.

Complete step by step answer:
As we know that the free radical polymerization contains three steps viz. initiation, propagation and termination. First step that initially creates a radical species is called initiation. Addition of the radical species attacks the double bond of the fresh monomer is called propagation. To form a stable, non-radical adduct, is called termination when two free radicals react each other.
A.Polyethylene
It is a simplest hydrocarbon polymer and a commonly used polymer. Polyethylene chemical formula is ${\left( {{C_2}{H_4}} \right)_n}$. Ethylene monomers are added to get polyethylene. There are two varieties of polyethylene viz. Low Density Polyethylene and High Density Polyethylene. Branched polyethylene is made by free-radical polymerization. Therefore, the option A is correct.
B.HDPE
We have to remember that HDPE means High Density Polyethylene. It is linear. HDPE is $90\%$crystalline. It is made by coordination polymerization and another method is done with the help of metal oxide as a catalyst. HDPE is made by methods through low pressure via free radical polymerisation. Therefore, the option B is correct.
C.LDPE
We must know that the LDPE-Low Density Polyethylene. It is a one type of polyethylene. It is produced at extremely high pressure polymerization of ethylene and oxygen is the initiator. Because of the high pressure, LDPE has many branches. The production mechanism for the LDPE is free-radical polymerization. Therefore, the option C is correct.
D.Teflon
It is also known as polytetrafluoroethylene (PTFE) (general formula ${(C{F_2} - C{F_2})_n}$), but Teflon is well known name and also a trade name. The name suggests, PTFE prepared from ethylene. The mechanism is free-radical polymerization. Therefore, the option D is correct.
From the above information polyethylene, LDPE and Teflon is made by free-radical polymerization.

So, the correct answer is Option A,B,C,D.

Note: As we know that polyethylene is an important plastic and many plastic items are prepared from polyethylene. LDPE is used as a plasticizer and mainly used for wrapping and packing food, textile products. HDPE is used in production of toys and household articles. Teflon is used in the production of valves and pipes, which require chemical resistance.