Question

Plexiglass, also known as PMMA is a polymer of :
(A) Methyl acrylate
(B) Methyl methacrylate
(C) Acrylic acid
(D) None of these

Answer 1

In the above question, it is asked about the monomer of plexiglass or PMMA. The answer lies in the full form of PMMA. It is used as a substitute as a glass in structure. PMMA is an ester of methacrylic acid.

Complete step by step solution:
PMMA is an ester of methacrylic acid which belongs to the important acrylic family of resins. Now-a-days, it is basically obtained from propylene which is a compound refined from the lighter fractions of crude oil.
The full form of PMMA is Poly(methyl methacrylate). Hence, PMMA is a polymer of methyl methacrylate.
So, the correct option is option B.

Additional information:
The presence of the methyl ( ${\text{C}}{{\text{H}}_{\text{3}}}$ ) groups prevents the polymer chains from packing closely in a crystalline fashion and from rotating freely around the carbon-carbon bonds. Because of this, PMMA is a tough and rigid plastic. In addition, it has almost perfect transmission of visible light, and, because it retains these properties over years of exposure to ultraviolet radiation and weather. Hence, it can be used as a substitute of glass. PMMA is also used in various applications which includes domed skylights, swimming pool enclosures, aircraft canopies, instrument panels, and luminous ceilings.

Note:
Plexiglass is the other name of acrylic. This is because acrylic is the usual abbreviation for polymethyl methacrylate, and Plexiglass is one of the many brand names of this plastic. Over time this brand name has become generic as 'plexiglass'.
Manufacturers, now-a-days, use plexiglass for light and instrument casings in cars, and to make appliances and eyewear lenses.