---
title: "Nylon, Teflon and epoxy resin"
subject: "Engineering Chemistry"
chapter: 4
key: "semester_2/engineering_chemistry:nylon-teflon-epoxy"
source: https://www.bctengineer.com/q/semester_2/engineering_chemistry/nylon-teflon-epoxy
site: BCT Engineering
---

# Nylon, Teflon and epoxy resin

Engineering Chemistry · Chapter 4: Engineering Polymers

- Asked in: 2075 Baisakh, 3+2 marks
- Video: [Epoxy resin preparation](https://www.youtube.com/watch?v=Ez88aRzsVrU) — Chemistry with Imtiaz Mari
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_2/engineering_chemistry/nylon-teflon-epoxy
- Whole chapter: https://www.bctengineer.com/md/semester_2/engineering_chemistry/chapter-4

## Question

Nylon and Teflon are different polymers. Explain. Give the preparation and uses of epoxy resin.

## Short answer

Nylon 6,6 is a condensation polyamide from hexamethylenediamine and adipic acid; Teflon is an addition polymer of tetrafluoroethylene, giving non-stick inertness. Epoxy resin is made from bisphenol-A and epichlorohydrin in NaOH, cured with polyamine. Uses: adhesives, coatings, electrical insulation, composites.

## Answer

#### Nylon and Teflon are different polymers
| Point | Nylon 6,6 | Teflon (PTFE) |
|---|---|---|
| Type | Condensation polymer (polyamide) | Addition polymer |
| Monomers | Hexamethylenediamine + adipic acid | Tetrafluoroethylene, CF₂=CF₂ |
| Linkage | Amide –CONH– | C–C and C–F |
| By-product | Water | None |
| Properties | Strong, tough, elastic fibre | Inert, heat resistant, non-stick, low friction |
| Uses | Ropes, fabrics, socks, gears | Non-stick cookware, gaskets, insulation |

**Nylon 6,6** is a polyamide made by condensation polymerisation of hexamethylenediamine (6 carbons) and adipic acid (6 carbons) at about 250 °C under pressure:

n H₂N(CH₂)₆NH₂ + n HOOC(CH₂)₄COOH → [–NH(CH₂)₆NH–CO(CH₂)₄CO–]ₙ + 2n H₂O

The repeating unit has the amide (–CONH–) link. (Nylon 6 is made from caprolactam by ring-opening polymerisation.)

**Teflon (PTFE, polytetrafluoroethylene)** is made by free-radical **addition polymerisation** of tetrafluoroethylene (TFE) using a persulphate initiator under pressure:

n CF₂=CF₂ → [–CF₂–CF₂–]ₙ

TFE itself is obtained by heating chlorodifluoromethane (CHClF₂) at 600–800 °C.

#### Preparation and uses of epoxy resin
Epoxy resins are thermosetting polymers containing epoxide (oxirane) groups. They are made by condensing **bisphenol-A** with **epichlorohydrin** in presence of NaOH (about 50–60 °C):

```text
HO–R–OH + 2 ClCH₂–CH–CH₂   --NaOH, –2HCl-->
(bisphenol-A)      \ /
                    O  (epichlorohydrin)

CH₂–CH–CH₂–O–R–O–CH₂–CH–CH₂    (n = 0)
  \ /                 \ /
   O                   O
where R = C₆H₄–C(CH₃)₂–C₆H₄
Higher polymers: more –CH₂–CH(OH)–CH₂–O–R–O– units inside.
```
The product is a liquid or low-melting prepolymer with epoxide end groups. It is **cured** (hardened) by adding a hardener such as a polyamine (ethylenediamine, triethylenetetramine) or an acid anhydride, which opens the epoxide rings and forms a cross-linked network.

**Uses:**
- Strong adhesives (Araldite) for metal, glass and ceramics.
- Surface coatings, paints and protective linings for tanks and pipes.
- Electrical insulation and potting of electronic components; glass-epoxy laminates for printed circuit boards.
- Matrix of fibre-reinforced composites (aircraft, boats, sports goods).
- Flooring, castings, moulds and tools.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. How do nylon 6,6 and Teflon differ in polymerisation type?
   A. Nylon is addition, Teflon is condensation
   B. Both are condensation polymers
   C. Nylon is condensation (releases water), Teflon is addition (no by-product)
   D. Both are addition polymers
   Answer: C. Nylon 6,6 forms by condensation releasing water; PTFE forms by addition of CF2=CF2 with no by-product. (Key point: Type of polymerisation)

2. Which monomers form nylon 6,6?
   A. Caprolactam
   B. Tetrafluoroethylene
   C. Phenol and formaldehyde
   D. Hexamethylenediamine and adipic acid
   Answer: D. Both monomers have 6 carbons, giving nylon 6,6 with amide links. (Key point: Nylon monomers)

3. How is Teflon prepared?
   A. Free-radical addition of tetrafluoroethylene with persulphate under pressure
   B. Condensation of diamine and diacid
   C. Ring-opening of caprolactam
   D. Hydrolysis of silanes
   Answer: A. n CF2=CF2 gives [-CF2-CF2-]n using persulphate initiator. (Key point: Teflon preparation)

4. How is epoxy prepolymer hardened?
   A. By cooling
   B. By adding a polyamine or anhydride hardener forming a cross-linked network
   C. By adding more epichlorohydrin only
   D. By removing NaOH
   Answer: B. Hardeners open the epoxide rings and cross-link the chains. (Key point: Epoxy curing)

## Related in Engineering Chemistry

- [Epoxy resin preparation and uses](https://www.bctengineer.com/question.md?key=semester_2%2Fengineering_chemistry%3Aepoxy-resin) — Engineering Chemistry, chapter 4, asked 2×
- [Biodegradable polymers; Nylon and Teflon](https://www.bctengineer.com/question.md?key=semester_2%2Fengineering_chemistry%3Abiodeg-nylon-teflon) — Engineering Chemistry, chapter 4
- [Biodegradable polymers; epoxy resin and polystyrene](https://www.bctengineer.com/question.md?key=semester_2%2Fengineering_chemistry%3Abiodeg-epoxy-polystyrene) — Engineering Chemistry, chapter 4
- [Thermosetting polymer; uses of epoxy resin](https://www.bctengineer.com/question.md?key=semester_2%2Fengineering_chemistry%3Athermosetting-epoxy-uses) — Engineering Chemistry, chapter 4
- [Monomers of polyurethane, nylon 6,6, Bakelite, epoxy](https://www.bctengineer.com/question.md?key=semester_2%2Fengineering_chemistry%3Amonomers-polymers) — Engineering Chemistry, chapter 4
- [Thermoplastic vs thermosetting polymers; Bakelite, epoxy](https://www.bctengineer.com/question.md?key=semester_2%2Fengineering_chemistry%3Athermoplastic-thermosetting) — Engineering Chemistry, chapter 4