Problem 31 - A Complete Resource Book in Chemistry for JEE Main

Question

Plexiglas (PMMA) is a polymer of (a) methyl methacrylate (b) methyl acrylate (c) acrylic acid (d) none of these

Step-by-Step Solution

Answer

The polymer of Plexiglas (PMMA) is methyl methacrylate.

Step 1: Understanding Plexiglas

Plexiglas is a common name for commercial and industrial usage of polymethyl methacrylate (PMMA), which is a transparent thermoplastic commonly used as a lightweight or shatter-resistant alternative to glass. It is important to match its chemical structure to the correct monomer.

Step 2: Identifying the Monomer

To identify the monomer from which PMMA is synthesized, we recall that PMMA stands for polymethyl methacrylate. The prefix 'poly-' indicates it is a polymer, and 'methyl methacrylate' refers to the repeating unit or monomer from which it is polymerized.

Step 3: Matching with Options

Now, we will match the correct chemical name of the monomer to the given options: (a) methyl methacrylate, (b) methyl acrylate, (c) acrylic acid, (d) none of these. Since PMMA is specifically polymethyl methacrylate, option (a) is correct.

Key Concepts

Plexiglas

Plexiglas, also known by its technical name polymethyl methacrylate (PMMA), stands out for its clarity and versatility. Often recognized as a clear, lightweight plastic, Plexiglas is widely favored for its shatter-resistant properties.
This makes it a popular substitute for glass in many applications. It finds uses in everything from windows, aquariums, to even lenses in eyeglasses. Unlike glass, Plexiglas is lighter, weighing in at about half the weight of a comparably sized piece of glass.

• Transparency: Plexiglas allows up to 92% of visible light to pass through it, rivaling the transparency of clean glass.
• Weather Resistance: It has excellent weatherability, retaining its clarity and strength even after prolonged exposure to sunlight and weather.
• Easy to Fabricate: Plexiglas can be easily cut, drilled, and shaped with standard tools found in workshops.

These characteristics make Plexiglas an indispensable material in a myriad of industries.

Methyl Methacrylate

Methyl methacrylate, commonly abbreviated as MMA, is a chemical building block used extensively in the manufacture of polymers. It’s a colorless liquid with a sharp, fruity odor, and is notable for its ability to polymerize easily.
This ability to link together into long chains forms the basis for PMMA production.

• Monomer Form: MMA serves as the monomer, or single unit, that polymerizes to form Plexiglas.
• Volatile Substance: It's important to handle MMA with care due to its volatile nature and potential health hazards during inhalation.
• Versatile Usage: Beyond being a precursor for PMMA, methyl methacrylate is also employed in the production of coatings, adhesives, and sealants due to its capable bonding properties.

Understanding its properties and uses helps appreciate the processes that lead to popular applications of PMMA.

Polymethyl Methacrylate (PMMA)

Polymethyl methacrylate (PMMA) is a fascinating polymer that exemplifies the transformation from a simple monomer to a complex material used across various sectors. PMMA is created through the polymerization of methyl methacrylate (MMA), forming long polymer chains.
This transformation involves combining numerous MMA molecules together.

• Thermoplastic Nature: PMMA is a thermoplastic, which means it becomes pliable or moldable above a specific temperature and solidifies upon cooling.
• Mechanical Properties: Many appreciate PMMA for its toughness, low cost, and ease of handling compared to glass.
• Wide Applications: It finds applications in automotive lights, signage, and protective barriers due to its clarity and break resistance.

The polymerization process ensures that PMMA retains both strength and transparency characteristics, making it an essential component in many commercial products.