Last Updated: May 2026
NEET Chemistry Polymers 2027 covers a low-volume but consistently-tested chapter from Class 12. Expect 1–2 questions every year, often based on monomer-polymer mapping and natural vs synthetic classification. This guide gives compact NCERT-aligned notes plus 30 practice MCQs.
Chapter Overview — NCERT Class 12 Chapter 15
- Weightage in NEET Chemistry: 1–2 questions
- NCERT pages: ~17
- Concept density: low — mostly memorisation
1. What is a Polymer?
A polymer is a high-molecular-mass macromolecule formed by repetitive linking of small molecules called monomers. The process of formation is called polymerisation.
Polymer = (monomer)n, where n is the degree of polymerisation.
2. Classification of Polymers
2.1 Based on Source
| Type | Examples |
|---|---|
| Natural | Starch, cellulose, proteins, natural rubber |
| Semi-synthetic | Cellulose acetate (rayon), cellulose nitrate |
| Synthetic | Polyethene, nylon, Bakelite, Buna-S |
2.2 Based on Structure
| Structure | Examples | Property |
|---|---|---|
| Linear | HDPE, nylon, polyester | High density, packed |
| Branched chain | LDPE | Low density |
| Cross-linked | Bakelite, Melamine | Hard, infusible (thermosetting) |
2.3 Based on Mode of Polymerisation
- Addition polymers — formed by addition of monomers (no by-product). Example: polyethene from ethene
- Condensation polymers — formed by condensation with elimination of small molecules (water, alcohol, etc.). Example: nylon, polyester
2.4 Based on Molecular Forces
| Type | Forces | Examples |
|---|---|---|
| Elastomers | Weakest van der Waals + cross-links | Buna-S, Buna-N, neoprene |
| Fibres | Strong H-bonds/dipole-dipole | Nylon-6,6, polyester (Terylene) |
| Thermoplastic | Intermediate | Polyethene, polystyrene, PVC |
| Thermosetting | Cross-linked, irreversible | Bakelite, Melamine, Urea-formaldehyde |
3. Important Addition Polymers (Monomer → Polymer)
| Monomer | Polymer | Use |
|---|---|---|
| Ethene (CH2=CH2) | Polyethene | Bags, bottles |
| Propene | Polypropene | Ropes, fibre |
| Vinyl chloride | PVC | Pipes, cables |
| Styrene | Polystyrene | Insulation, packaging |
| Tetrafluoroethene | Teflon (PTFE) | Non-stick cookware |
| Acrylonitrile | Polyacrylonitrile (Orlon) | Synthetic wool |
| Isoprene (2-methyl-1,3-butadiene) | Natural rubber | Rubber items |
| Buta-1,3-diene + styrene | Buna-S (SBR) | Tyres |
| Buta-1,3-diene + acrylonitrile | Buna-N | Oil-resistant rubber |
| 2-Chloro-buta-1,3-diene | Neoprene | Conveyor belts |
4. Important Condensation Polymers
| Polymer | Monomers | Linkage | Use |
|---|---|---|---|
| Nylon-6,6 | Hexamethylenediamine + Adipic acid | Amide | Carpets, fabrics |
| Nylon-6 | Caprolactam | Amide | Tyre cords |
| Terylene (Dacron) | Ethylene glycol + Terephthalic acid | Ester | Synthetic fibre |
| Bakelite | Phenol + Formaldehyde | Cross-linked | Combs, electrical switches |
| Melamine-formaldehyde | Melamine + Formaldehyde | Cross-linked | Unbreakable crockery |
| Glyptal | Ethylene glycol + Phthalic acid | Ester | Paints |
5. Biodegradable Polymers
| Polymer | Monomers | Use |
|---|---|---|
| PHBV (poly-β-hydroxybutyrate-co-β-hydroxyvalerate) | 3-hydroxybutyric acid + 3-hydroxypentanoic acid | Sutures, drug delivery |
| Nylon-2,Nylon-6 | Glycine + Aminocaproic acid | Biodegradable plastic |
6. Vulcanisation of Rubber
Charles Goodyear (1839) discovered that heating natural rubber with sulphur (1–5%) causes cross-linking of the polyisoprene chains, converting soft rubber into a tough, elastic material. Sulphur bridges (S–S) form between cis-1,4-polyisoprene chains.
NEET High-Yield Quick Facts
- Natural rubber is cis-1,4-polyisoprene; gutta-percha is trans-1,4-polyisoprene
- Buna-S = Styrene-Butadiene Rubber, Buna-N = Acrylonitrile-Butadiene Rubber
- Nylon-6,6 has 6 carbons in each monomer (HMD + adipic); Nylon-6 has 6 carbons in single caprolactam
- Bakelite is a thermosetting polymer; once set, it cannot be remoulded
- Teflon = PTFE = polytetrafluoroethene — chemically inert, used for non-stick coatings
- Glyptal is a polyester from ethylene glycol + phthalic acid
30 Practice MCQs (NEET Pattern)
[cg_quiz id=”neet-polymers-2027″]
FAQ
Q1. Are polymers really tested in NEET?
Yes — 1–2 questions consistently every year. NEET 2018, 2020, 2022, 2024 all had at least one polymer question.
Q2. What’s the most common test pattern?
Match the column: monomer ↔ polymer, or identify the linkage type (amide vs ester), or thermoplastic vs thermosetting.
Q3. Are biodegradable polymers important?
Yes — PHBV is a NEET favourite. Know that it is biodegradable and the constituent monomers.
Q4. Do I need to memorise reactions?
No mechanism is required. Only monomer-polymer pairing and classification. Skip mechanism details for this chapter.