Chapter 3 — Synthetic Fibres And Plastics

What is a fibre?
A fibre is a long, thin, hair-like structure whose length is very large compared to its thickness. Fibres can be spun into yarn and woven into fabrics. They are the basic building blocks of textiles and many everyday materials.

Classification

• Natural fibres — obtained from plants, animals or minerals. Examples: cotton (plant), wool and silk (animal), asbestos (mineral).
• Synthetic (man-made) fibres — made by humans, usually from chemical compounds (polymers). Examples: nylon, polyester (Terylene), acrylic, rayon (artificial silk).

Structure and composition
Many fibres are polymers — long chains of repeating units. Natural cellulose (in cotton) has repeating glucose units (written as (C6H10O5)n). Synthetic fibres such as nylon and polyester are formed by polymerisation of small monomers into long chains.

Important properties of fibres

• Length and fineness — fine fibres make soft, smooth fabrics.
• Tensile strength — ability to withstand pulling forces (important for ropes, parachutes).
• Elasticity — ability to regain shape after stretching (e.g., wool is elastic).
• Absorbency — amount of water a fibre can absorb (cotton absorbs well; polyester does not).
• Thermal properties — flame resistance and heat conduction vary by fibre (wool is more heat resistant than polyester).
• Durability and biodegradability — many synthetic fibres are not readily biodegradable.

How synthetic fibres are made (brief)
Basic steps: polymerisation (to form long-chain polymers) → spinning (forcing the polymer solution or melt through spinnerets to form fibres) → drawing (to align the polymer chains for strength) → finishing (dyeing, texturing).

Uses
Fibres are used in clothing, household textiles (bedsheets, curtains), industrial products (ropes, seat belts), medical textiles (bandages), and technical applications (parachutes, fishing nets).

Environmental note
Natural fibres are generally biodegradable; many synthetic fibres are oil-based and resist decomposition, causing waste and microplastic issues. Recycling and use of bio-based polymers are modern responses.

Introduction: Synthetic fibres are man-made fibres produced by chemical synthesis of monomers. Major synthetic fibres used in textiles and industry include nylon, polyester (Terylene/PET), acrylic and rayon (a regenerated fibre). They are made by polymerisation and condensation reactions and have properties tailored for specific uses.

Nylon: Nylon is a polyamide (commonly nylon-6,6). It is strong, elastic, light-weight, abrasion-resistant and dries quickly. Made by condensation of a diamine and a diacid, nylon is used for ropes, parachutes, fishing lines, stockings, shirts and carpets. Advantages: high strength and elasticity. Disadvantages: can be damaged by strong sunlight and some chemicals.

Polyester (Terylene / PET): Polyester is made by condensing ethylene glycol and terephthalic acid (PET). It is wrinkle-resistant, durable, quick-drying and retains shape well. Uses include garments (shirts, dresses), bedsheets, upholstery and bottles (as PET). Advantages: low maintenance and durable. Disadvantages: low moisture absorbency (feels less comfortable in hot weather) and is not easily biodegradable.

Acrylic: Acrylic fibres (made from polyacrylonitrile) are warm, wool-like, light and resistant to moths and mildew. Used in sweaters, blankets, socks and outdoor fabrics. Advantages: warm and colour-fast. Disadvantages: can pill and may melt at high temperatures.

Rayon (Viscose Rayon): Rayon is a regenerated cellulose fibre obtained from wood pulp (cellulose). It behaves like natural fibres (soft and absorbent) and is used for dresses, shirts, bed-linen and linings. It is semi-synthetic (regenerated natural polymer). Advantages: comfortable and breathable. Disadvantages: weaker when wet and may shrink or wrinkle on washing.

Environmental and care notes: Most fully synthetic fibres (nylon, polyester, acrylic) are not biodegradable and can shed microfibres during washing. Care labels should be followed: gentle wash, moderate heat for drying/ironing, and avoid prolonged exposure to strong sunlight for some fibres.

Summary of typical properties: nylon = high strength & elasticity; polyester = shape-retaining & low-wrinkle; acrylic = warm & wool-like; rayon = soft & absorbent (regenerated cellulose).

Synthetic fibres are man-made fibres produced from chemicals (mostly polymers). They are designed to have specific physical and chemical properties that make them useful in many everyday applications. Below are the important properties of synthetic fibres with simple explanations:

• Strength: Many synthetic fibres (e.g., nylon, polyester) are stronger than natural fibres of the same size. Strength means they can withstand larger forces without breaking. This makes them useful for ropes, parachutes and seat belts.
• Elasticity (Stretch and recovery): Synthetic fibres often have good elasticity — they can stretch and return to original shape (example: nylon stockings). Elasticity depends on molecular structure and fibre treatment.
• Durability and Wear Resistance: They resist abrasion and wear, so clothes and industrial fabrics last longer.
• Low Moisture Absorption: Most synthetic fibres absorb very little water (are hydrophobic). This makes them quick-drying but can reduce comfort because they do not absorb sweat well.
• Chemical Resistance: They resist many chemicals, acids and alkalis better than natural fibres. This makes them suitable for lab and industrial uses.
• Thermal Behavior and Burning Test: Under heat, synthetic fibres usually melt and may form hard beads and give a chemical or plastic smell when burnt. This is different from natural fibres (e.g., cotton burns to ash and smells like burning paper). Burn tests are often used to identify fibres.
• Lightweight: Synthetic fibres often have low density and are lightweight, useful for sportswear and outdoor gear.
• Wrinkle Resistance and Shape Retention: They resist creasing and retain shape well. This reduces ironing and makes them useful for easy-care clothing.
• Ease of Dyeing & Colour Fastness: Some synthetics (like polyester) can be dyed; others need special dyes or treatments. Colour fastness varies with fibre type and dye method.
• Static Electricity: Because they are poor conductors and absorb little moisture, synthetic fibres can build up static charge (clinging fabrics, sparks in dry conditions).
• Flammability and Safety Considerations: Many synthetics melt and may stick to skin when burning — this is a hazard. Flame-retardant treatments are used for safety fabrics.
• Maintenance: Most synthetic garments are easy to wash, dry quickly and resist mildew and insects, but they may retain oil stains and require special care for heat (can melt in high-temperature washing or ironing).
• Semi-synthetic fibres (like rayon): Made from natural cellulose processed chemically; they have some properties of both natural and synthetic fibres (e.g., comfortable like natural fibres but weaker when wet).

Summary (comparison): synthetic fibres = strong, durable, quick-drying, wrinkle-resistant, chemically resistant, but lower moisture absorption and can produce static and melt under high heat.

What are synthetic fibres? Synthetic fibres are man-made long-chain polymers produced from petrochemicals or regenerated cellulose. Common examples include nylon, polyester, acrylic and polypropylene. They are engineered for specific properties such as high strength, elasticity, stain resistance and fast drying.

Why they are widely used: their mechanical strength, light weight, low cost, resistance to rot, mildew and most chemicals, quick-drying nature and ability to be produced in consistent quality make them ideal for many applications. They are often blended with natural fibres to combine advantages (eg, cotton+polyester).

Main uses (by category)

• Clothing and textiles: everyday garments, sportswear, swimwear, raincoats, winter wear (acrylic as wool substitute), lingerie, microfibre cleaning cloths.
• Household and furnishing: carpets, curtains, upholstery, bed sheets, mattress covers, decorative fabrics.
• Industrial and safety: ropes, fishing nets, seat belts, parachutes, conveyor belts, tyre cords, geotextiles, filter fabrics.
• Medical and hygiene: surgical sutures (nylon), bandages, disposable gowns, non-woven surgical masks and wipes (polypropylene).
• Packaging and everyday items: non-woven shopping bags, carpets, toothbrush bristles (nylon), upholstery threads, industrial filters.

Advantages that determine use

• High tensile strength and toughness: useful for ropes, seat belts and parachutes.
• Elasticity and shape retention: useful in garments and hosiery.
• Low moisture absorption and quick drying: useful for sportswear and outdoor gear.
• Resistance to chemicals and microbes: useful in industrial and medical textiles.
• Cost-effective and easy to dye/finish: widely used in mass-produced clothing and home textiles.

Limitations and environmental note: Most synthetic fibres are non-biodegradable and can release microplastics into water during washing. Recycling and use of biodegradable/renewable alternatives are important steps to reduce environmental impact.

What is a monomer?
A monomer is a small, simple molecule that can join chemically with many similar molecules to form a long chain. Examples of monomers: ethene (CH2=CH2), vinyl chloride (CH2=CHCl), amino acids.

What is a polymer?
A polymer is a very large molecule (macromolecule) made by joining many monomer units in a chain. The repeating unit of the chain is called the repeating unit or mer. Polymers can be natural (proteins, cellulose, starch, natural rubber) or synthetic (polyethylene, PVC, nylon, polyester).

Representation of a polymer:
A polymer is often written as [-A-]n where A is the repeating unit and n is the degree of polymerisation (number of repeating units).

Polymerisation: the process
Polymerisation is the chemical process in which monomers link to form polymers. There are two main types:

• Addition (chain-growth) polymerisation: Monomers with a double bond (C=C) open up their double bond and link together without forming small molecules. Example: ethene molecules add together to form polyethylene.
• Condensation (step-growth) polymerisation: Two different monomers with two functional groups react to form a bond and eliminate a small molecule (often water or HCl). Example: formation of nylon by reaction of a diamine and a dicarboxylic acid with elimination of water.

Key features to remember
- Repeating unit: the basic unit shown in square brackets with subscript n.
- Degree of polymerisation (n): number of repeating units in a polymer chain.
- Molecular mass of polymer ≈ n × (molar mass of repeating unit) (approximate for linear polymers).

Why properties change with polymerisation
As monomers join into long chains, properties such as strength, melting point, viscosity and elasticity change. Longer chains and cross-linking usually increase strength and rigidity. The chemical nature of the repeating unit also determines properties (flexible vs rigid, resistant vs degradable).

Everyday importance
Understanding monomers and polymerisation explains how many familiar materials are made: plastic bags, bottles, pipes, clothing fibres (nylon, polyester), rubber products and many more.

Environmental note
Many synthetic polymers (plastics) do not biodegrade easily. Recycling, reuse and development of biodegradable polymers are important to reduce pollution.

What are plastics?
Plastics are synthetic (man-made) materials made of very large molecules called polymers. Polymers are long chains built by joining many small repeating units called monomers by chemical reactions (polymerisation). Plastics can be moulded into different shapes when heated or processed and then retain their shape.

How are plastics formed?
Plastics are formed by polymerisation of monomers. Two common types of polymerisation are addition (or chain-growth) polymerisation and condensation (or step-growth) polymerisation. In addition polymerisation, monomers add to each other without producing by-products. In condensation polymerisation, monomers join and small molecules such as water are released.

Two main types of plastics

• Thermoplastics: Soften on heating and can be remoulded repeatedly (e.g., polyethylene (PE), polyvinyl chloride (PVC), polystyrene (PS), polycarbonate (PC)). They are usually recyclable.
• Thermosetting plastics (thermosets): Harden permanently on heating and forming. After they set, they do not soften on reheating because of cross-linked molecular structure (e.g., Bakelite, melamine). These are generally not recyclable by melting.

Key properties of plastics

• Lightweight compared to metals and glass.
• Can be moulded into various shapes — good for mass production.
• Poor conductor of heat and electricity — useful as insulators.
• Durable and resistant to corrosion and chemical attack (depends on type).
• Some are transparent (e.g., polycarbonate), others are opaque or coloured easily.
• Many are water resistant and do not rot.

Uses
Because of the above properties, plastics are used in packaging (bags, bottles), pipes, toys, electrical insulation, household utensils, automobiles, medical devices, films, foams and many other applications.

Environmental aspects
Most common plastics are non-biodegradable and can cause pollution if not managed. Thermoplastics are often recyclable; thermosets are harder to recycle. Reducing use, reusing and recycling plastics, and using biodegradable or alternatives are important steps for environmental protection.

Important points to remember

• Plastics = polymers made from monomers by polymerisation.
• Thermoplastics can be remoulded; thermosets cannot.
• Common examples: polyethylene (bags), PET (bottles), PVC (pipes), Bakelite (electrical switches).
• Environmental concern: littering, microplastics, landfill and recycling challenges.

What are plastics? Plastics are high-molecular-weight materials (polymers) made by joining many small molecules (monomers). They are lightweight, mouldable and used widely in daily life.

Main classification (based on behaviour on heating)

• Thermoplastics: Soften or melt on heating and can be remoulded repeatedly. Their polymer chains are mostly linear or branched with weak intermolecular forces. Examples: polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), polyethylene terephthalate (PET).
• Thermosetting plastics (thermosets): Undergo irreversible chemical cross-linking on heating; once set they do not soften on reheating. They are hard, heat-resistant and are used where shape permanence and heat resistance are needed. Examples: Bakelite (phenol-formaldehyde), epoxy resins, urea-formaldehyde.

Common types, properties and typical uses

• Polyethylene (PE) — low-density (LDPE) is flexible, used for plastic bags, films; high-density (HDPE) is stronger, used for bottles, containers and pipes.
• Polyvinyl chloride (PVC) — rigid or flexible (with plasticisers); used for pipes, window frames, flooring, and electrical insulation.
• Polypropylene (PP) — tough, heat-resistant; used for food containers, ropes, car parts, and laboratory equipment.
• Polystyrene (PS) — rigid or foamed (expanded polystyrene/EPS); used for disposable plates, packing foam and insulation.
• Polyethylene terephthalate (PET, Terylene) — strong, used for beverage bottles, textile fibre (polyester) and packaging.
• Polyamides (Nylon) — strong fibres used in ropes, carpets, clothing and engineering parts.
• Bakelite and other thermosets — hard, heat-resistant; used for electrical switches, handles, adhesives and laminates.

Key differences (quick)

• Thermoplastics: soften on heating, recyclable by remelting, mostly linear chains.
• Thermosets: harden irreversibly, cannot be remelted, cross-linked networks.

Environmental and safety notes: Most conventional plastics are non-biodegradable and can cause pollution. Recycling codes (1–7) identify types to help recycling. Reduce, reuse and recycle are important. Burning plastics releases toxic gases; avoid improper disposal.

How to identify type in everyday life: Look for recycling symbol numbers (1 = PET, 2 = HDPE, 3 = PVC, 4 = LDPE, 5 = PP, 6 = PS, 7 = others). Softening on gentle heating indicates thermoplastic; if it chars and does not remelt, it is likely a thermoset.

What are plastics? Plastics are high molecular‑weight polymers made by joining many small repeating units (monomers). They are produced by chemical polymerisation and are mouldable when heated (in many types) and set into desired shapes.

Important properties of plastics

• Light weight: Most plastics have low density (low mass per unit volume) compared with metals and glass.
• Insulating behaviour: Good electrical and thermal insulators; widely used for wire insulation and appliance casings.
• Corrosion and chemical resistance: Resist water, many acids, bases and organic chemicals.
• Malleability and formability: Can be moulded, extruded or blown into complex shapes.
• Durability: Long service life; do not rot or corrode easily.
• Low melting/softening range (thermoplastics): Can be reheated and reshaped many times.
• Brittleness in some (thermosets): Thermosetting plastics harden irreversibly when heated and are usually rigid and hard (e.g., Bakelite).
• Poor biodegradability: Most traditional plastics persist in the environment unless recycled or specially treated.

Types of plastics (brief)

• Thermoplastics (e.g., polyethylene, PVC, PET): Soften on heating and can be reshaped; recyclable by melting.
• Thermosetting plastics (e.g., Bakelite, phenol‑formaldehyde; epoxy resins): Form a cross‑linked network on curing; cannot be remelted.

Common uses

• Packaging (films, bottles) — lightweight and moisture resistant.
• Household goods (containers, furniture, toys) — easy to mould and inexpensive.
• Electrical insulation and cable jackets — good dielectric properties.
• Construction (pipes, fittings, window frames) — corrosion resistant.
• Automobile parts and furniture — lightweighting to improve fuel efficiency.
• Medical devices (disposable syringes, implants) — biocompatible grades exist.

Environmental and safety notes

• Plastics can persist in landfills and oceans; recycling and reduced use of single‑use plastics are important.
• Burning many plastics releases toxic gases (dioxins, HCl, CO); avoid open burning.

Practical classroom/experiment ideas

• Compare flexibility of LDPE (plastic bag) and HDPE (rigid milk bottle) by bending.
• Observe softening of a thermoplastic (e.g., a plastic spoon) near hot water versus a thermoset (unchanged).

What this topic covers: Synthetic fibres and plastics are useful but many are non-biodegradable and cause long-term harm to land, water and air. This section explains how plastics affect the environment, the main hazards, and simple ways to reduce harm.

Why plastics are a problem: Most common plastics do not decompose quickly. They accumulate in landfills and nature, break into microplastics, and can release toxic additives. Plastics can block drains and harm animals that swallow or get entangled in them.

Main environmental impacts:

• Land pollution: Plastic waste fills landfills and litters fields and streets. Because it lasts for decades to centuries, it reduces usable land area and can change soil properties.
• Water pollution: Plastic items reach rivers and oceans. Marine animals may eat plastics or become entangled, causing injury or death. Plastics also break down into microplastics that enter the food chain.
• Air pollution: Burning plastics (open burning or uncontrolled incineration) releases toxic gases such as dioxins, furans and particulate matter, harming human health and contributing to air pollution.
• Soil and groundwater contamination: Additives and chemicals from some plastics can leach into soil and groundwater, affecting plant growth and water quality.
• Wildlife hazards: Birds, fish, and mammals can mistake plastics for food. Microplastics may accumulate in organisms and move up the food chain to humans.

Specific hazards from synthetic fibres: When washed, synthetic clothes (like polyester) shed tiny plastic fibres (microfibres) that pass through sewage treatment and reach water bodies. These microfibres can be ingested by aquatic organisms.

Human health concerns: Microplastics have been found in seafood, drinking water and salt. Burning plastics releases toxic chemicals linked to respiratory problems and other illnesses.

Prevention and management (simple actions): Reduce use of single-use plastics, reuse items, recycle correctly, support bans on open burning, use alternatives (paper, metal, glass, natural fibres) when possible, and choose washable bags and containers. Proper waste segregation and community clean-up programs help reduce pollution.

Key takeaways: Plastics are durable but that durability causes long-term pollution. Small individual actions (reduce, reuse, recycle) plus proper waste management reduce hazards to ecosystems, animals and people.

Overview
Management, recycling and alternatives deal with how we handle synthetic fibres and plastics after use so they do not harm the environment. The main goal is to reduce the amount of plastic that reaches landfills and nature, reuse materials where possible, and replace harmful plastics with safer alternatives.

Key principles — The 3 R's

• Reduce: Use less plastic (buy bulk, avoid single-use items).
• Reuse: Use items many times (cloth bags, refillable bottles).
• Recycle: Convert waste into raw material for new products.

Plastic waste management steps

• Segregation at source: Separate dry (plastics, metals) and wet (food) waste at home or school.
• Collection: Local collection systems, buy-back centres, community drives.
• Sorting: Sort plastics by type (PET, HDPE, LDPE, PP etc.).
• Cleaning: Remove food and labels; wash and dry.
• Processing: Shredding/granulating, melting/extrusion, pelletizing for new products.
• Final use: Recycled pellets used to make new bottles, fibres, packaging, or products.

Types of recycling

• Mechanical recycling: Physically reprocessing plastic (washing & melting) into pellets.
• Chemical recycling: Breaking polymers into monomers/chemicals to make new plastics (useful for contaminated or mixed plastics).
• Energy recovery: Incineration to produce energy (used if recycling is not feasible, but produces emissions).
• Biological routes: Composting of biodegradable plastics or organic materials.

Alternatives to conventional plastics

• Biodegradable plastics: Made from plant starches or specially designed to break down faster under composting conditions.
• Natural fibres: Cotton, jute, hemp and silk used instead of synthetic fibres in clothing and bags.
• Reusable materials: Glass, stainless steel, and durable cloth bags and containers.
• Design changes: Reducing packaging, designing for easier recycling (mono-material packaging).

Why management matters
Plastics can take decades to centuries to decompose. Poor disposal causes microplastics, harms wildlife, clogs drains, and wastes resources. Proper management saves energy, raw materials and reduces pollution.

Roles and actions

• Individuals: Refuse single-use plastics, segregate waste, choose reusable items.
• Schools & communities: Conduct collection drives, awareness campaigns, set up segregation bins.
• Industry & government: Implement Extended Producer Responsibility (EPR), bans on some single-use plastics, invest in recycling infrastructure.

Simple lifecycle example (pet bottle)
A used PET bottle can be collected, cleaned, shredded into flakes, melted and extruded into polyester fibres (for jackets or carpets) or reformed into new bottles. This reduces demand for virgin petroleum-based raw material.

Limits & cautions
Not all plastics are easy to recycle (mixed or contaminated plastics). Biodegradable plastics need proper industrial composting conditions and will not quickly degrade in open dumps.

Takeaway
Good management means reduce first, then reuse, and recycle properly. Where possible, choose alternatives that are reusable or truly biodegradable under local composting conditions.

Goal: Learn simple, safe tests to identify and compare synthetic fibres and plastics and to distinguish them from natural fibres/plastics.

Overview: The chapter suggests a few school-level activities that help students observe characteristic physical and chemical behaviour of fibres and plastics. These include burning tests, water-absorption tests, elasticity/strength tests and simple heating tests to tell thermoplastics from thermosetting plastics. Always perform these activities under a teacher's supervision and follow safety rules (small samples, well-ventilated area, safety goggles, use of tongs, and no inhalation of fumes).

1. Burning test (distinguish natural vs synthetic fibres): Take a tiny fibre sample (cotton, wool, silk, nylon, polyester). Use tweezers and bring the sample close to a flame for a moment and then remove it. Observe flame behaviour, smell and residue.
• Cotton: burns like paper, bright flame, smell of burning paper or plants, leaves soft grey ash.
• Wool/silk: burns slowly, curls away from flame, smells like burning hair (due to protein), leaves a hard, black, brittle bead.
• Nylon/Polyester (synthetic): melts, may drip, may continue to burn or self-extinguish depending on type; gives a sweet or chemical smell and leaves a hard bead.
2. Water absorption test (hydrophilic vs hydrophobic): Put a small drop of water on samples. Natural fibres (cotton, wool) absorb water and wet quickly. Many synthetic fibres (polyester, nylon) are water-repellent and the drop beads or is absorbed slowly.
3. Elasticity/strength test (compare stretch & recovery): Hang a small weight or apply a known load to equal lengths of different fibres and measure extension. Natural fibres and some synthetics behave differently — nylon is very elastic, cotton less so. This can be related to stress–strain behaviour and Hooke's law in the elastic region.
4. Thermoplastic vs thermosetting plastics (heating test): Heat a small piece of plastic gently (use a hot water bath of increasing temperature or a hot wire under supervision). Thermoplastics (e.g., polyethylene, polystyrene, PVC) soften and may melt on heating and can be remoulded. Thermosetting plastics (e.g., bakelite, melamine) do not soften on heating; they char and may burn.
5. Static electricity activity: Rub a plastic comb or PVC rod on wool or dry hair and bring near small paper bits to see attraction. This demonstrates that some plastics accumulate static charge.

Interpretation: Combine observations from several simple tests to identify a sample. For example, a fibre that melts and forms a hard bead with a chemical odour and is water-repellent is likely synthetic. A fibre that smells of burning hair and leaves a brittle bead is protein-based (wool/silk).

Safety note: Burning tests produce fumes. Use tiny samples, perform under a fume hood or in open air, and follow teacher instructions. Do not use strong acids or other hazardous chemicals for classroom tests unless authorised and properly controlled.

Introduction: Synthetic materials (synthetic fibres such as polyester, nylon, acrylic and man-made plastics such as PVC, polythene) are manufactured from petrochemicals. They are generally strong, quick-drying, and crease-resistant, but many are heat-sensitive, prone to static build-up, and can attract oil-based stains. Proper care prolongs life, retains appearance and reduces environmental impact.

Key properties affecting care:

• Low moisture absorbency (dries quickly but holds oil stains).
• Sensitivity to high temperature (can melt, shrink or distort).
• Static electricity builds up easily in low humidity.
• Good chemical resistance to many detergents but some solvents or bleaches can damage colours/structure.
• Susceptible to microfibre shedding during washing (environmental concern).

General care guidelines for synthetic fabrics:

• Always check the care label (wash temperature, bleaching, tumble-dry and ironing instructions).
• Sort laundry by colour, fabric type and level of dirt to avoid abrasion and dye transfer.
• Use mild liquid detergents; avoid excessive detergent which can leave residues.
• Wash at low to moderate temperatures (cold or lukewarm) unless label allows higher temps — high heat can melt or weaken fibres.
• Use gentle cycle and lower spin speeds for delicate synthetics (nylon stockings, delicate polyester blends).
• Use mesh wash bags for small/delicate items to prevent snagging and reduce microfibre release.
• Dry in shade or tumble-dry on low heat if permitted. Avoid prolonged direct sunlight for coloured synthetics which can fade finishes.
• Iron on the lowest appropriate setting and use a press cloth; many synthetics require ‘cool’ iron or no iron at all.
• Reduce static by using fabric softener or an anti-static spray; increasing humidity also helps.
• Store clean and dry; fold stretch-prone knits (acrylic) rather than hang to avoid stretching. Keep away from heat sources that can deform plastics.

Stain removal tips (act quickly):

• Oil/grease: blot excess, pre-treat with a small amount of liquid dish soap or a solvent recommended on label; launder as usual.
• Protein stains (blood, sweat): rinse with cold water first (hot water can set protein stains), then use enzyme detergent if safe for fabric.
• Ink: test an inconspicuous area; use alcohol-based remover carefully.
• Bleach: use oxygen bleach (color-safe) for many synthetics; avoid chlorine bleach on coloured synthetics unless label permits.
• Always test any chemical on a hidden area first and follow manufacturer's instructions.

Care of plastic items (toys, containers, raincoats):

• Clean with mild soap and water; avoid abrasive cleaners that scratch surfaces.
• Do not expose to high heat (e.g., open flame, hot oven, non-microwave-safe use) — some plastics can warp or release harmful fumes.
• Avoid harsh solvents that may dissolve or craze plastic (acetone, some paint strippers).
• Store away from direct sunlight long-term to prevent brittleness or colour fading.
• Check recycling symbols and dispose/recycle responsibly to reduce environmental impact.

Environmental & safety considerations:

• Microfibres released during washing contribute to water pollution — reduce by using cooler washes, gentler cycles, mesh bags or filtration systems (e.g., washing machine filters, Guppyfriend-like bags).
• Avoid overuse of single-use plastics; repair, reuse and recycle when possible.
• Follow safe dilution and handling for detergents/bleaches — store chemicals out of children’s reach.

Summary (Do's and Don'ts):

• Do read labels, use recommended temperatures, and pre-treat stains promptly.
• Do use gentle detergents, mesh bags, and low-heat drying/ironing.
• Don't use very high heat, strong solvents or abrasive cleaners on synthetics.
• Don't forget environmental practices: full loads, filters for microfibres, and proper disposal.

Polymers and monomers
A polymer is a very large molecule made up of many repeating small units called monomers. Synthetic fibres and plastics are made by joining monomers together in long chains.

Polymerisation (how polymers form)
There are two main types of polymerisation:

• Addition (chain) polymerisation — monomers with double bonds (like ethene) add together without producing small byproducts (e.g., ethene → polyethylene).
• Condensation polymerisation — two different monomers react and each time a bond is formed a small molecule (usually water) is eliminated (e.g., acid + alcohol → polyester + water; diamine + diacid → nylon + water).

Common synthetic fibres
Nylon, polyester (Terylene), acrylic and rayon (regenerated cellulose) are widely used. They are chosen for properties such as strength, elasticity, wrinkle resistance and quick drying.

Common plastics
Plastics are broadly classified as thermoplastics (soften/melt on heating; can be remoulded — e.g., polyethylene, polypropylene, PVC, polystyrene) and thermosetting plastics (set permanently on heating and do not melt on reheating — e.g., Bakelite, melamine).

Key properties
Important properties that distinguish fibres and plastics include tensile strength, elasticity, density, water absorption, thermal resistance and biodegradability. Synthetic materials often have high strength, low water absorption and low biodegradability.

Environmental aspects
Most synthetic plastics are non-biodegradable and can cause pollution and microplastic formation. Recycling (collect, sort by polymer type, reprocess) and using biodegradable alternatives are important mitigation steps. Disposal by burning releases toxic gases; controlled recycling or chemical recycling is preferred.

Terms to remember (short)

• Monomer — repeating small unit.
• Polymer — long chain of repeating monomers.
• Polymerisation — process of forming polymers.
• Synthetic fibre — man-made fibre produced by polymerisation.
• Thermoplastic — melts on heating; recyclable by remoulding.
• Thermoset — irreversibly set on heating; does not melt again.
• Biodegradable — broken down by biological processes.

How to visualise the structure
A polymer can be shown as a long chain with a small boxed unit repeated many times. This repeated unit is called the repeating unit or mer.