Is Nylon the Same as Polyester? Polymer & Fabric Differences
No. Nylon and polyester are different polymer families. Nylon is a polyamide, built from -CO-NH- (amide) linkages between diamines and dicarboxylic acids. Polyester — almost always polyethylene terephthalate (PET) in apparel — is built from -CO-O- (ester) linkages between ethylene glycol and terephthalic acid. They behave differently: nylon is stronger and stretchier, polyester is more UV-resistant, more hydrophobic (0.4% moisture regain vs nylon’s ~4.5% per Morton & Hearle, 2008), and cheaper to produce.
Most consumer-facing comparisons treat nylon and polyester as nearly interchangeable synthetics. The chemistry and performance data tell a different story. Both are thermoplastic petroleum-derived polymers; both are melt-spun; both shed microfibers. But the amide linkage and the ester linkage produce fibers with different bonding to water, different stress-strain curves, different dyeing chemistry, and different end-of-life pathways. Values below come from standard textile-physics references (Morton & Hearle, 2008; Cook, Handbook of Textile Fibres, Vol. 2), peer-reviewed studies, and ASTM/AATCC/ISO test methods.
The short answer
Nylon and polyester are not the same fiber. Three points capture the distinction:
- Polymer family. Nylon is a polyamide; polyester is a polyester. The repeating linkage in the polymer chain is different: -CO-NH- (amide) for nylon, -CO-O- (ester) for polyester. This single chemical difference explains most of the property gap.
- Common forms in apparel. “Nylon” on a label means almost always nylon-6 (PA6) or nylon-66 (PA66). “Polyester” on a label means almost always polyethylene terephthalate (PET). Other polyamides (aramids — Kevlar®, Nomex® by DuPont) and other polyesters (PEN, PBT, PLA) exist but are rare in conventional apparel.
- Headline performance differences. Per Morton & Hearle (2008), nylon-6 has a moisture regain of ~4.5% at 65% RH and 20 °C; PET has 0.4%. Per ASTM D4157 (Wyzenbeek), high-tenacity nylon weaves can exceed 80,000 double rubs; comparable polyester typically reaches 30,000-60,000. Nylon-6 melts near 220 °C; PET melts near 260 °C. Nylon densifies at 1.14 g/cm³; PET at 1.38 g/cm³.
What is nylon?
Nylon is the trade name DuPont introduced in 1938 for the first commercial synthetic polyamide (Carothers, US Patent 2,130,948). The first commercial application was nylon stockings, released to the U.S. market on May 15, 1940.
A polyamide is any polymer containing the -CO-NH- (amide) linkage in its backbone. The amide bond gives nylon two distinguishing properties: strong intermolecular hydrogen bonding between adjacent polymer chains (high tensile strength), and an ability to hold modest amounts of water within the polymer (moisture regain near 4-4.5% — much higher than polyester’s 0.4%, much lower than cotton’s 7-8.5%).
The two nylons that dominate apparel are nylon-6 (PA6) and nylon-66 (PA66). The numbers refer to the carbon counts in the monomers:
- Nylon-6 is polymerized from a single monomer, ε-caprolactam (a 6-carbon ring), via ring-opening polymerization. It melts near 220 °C, has a glass transition (Tg) near 50 °C, and is the most common nylon in fashion knitwear, hosiery, and swimwear.
- Nylon-66 is polymerized from two monomers — hexamethylenediamine (6 carbons) and adipic acid (6 carbons) — via condensation polymerization. It melts near 265 °C, has a Tg near 70 °C, and is preferred for high-temperature and high-abrasion applications including industrial fabrics, tire cord, and outdoor gear.
Other nylons (nylon-11, nylon-12, nylon-46) exist in technical and engineering fibers but rarely appear in casual apparel. The aramids — meta-aramid Nomex® and para-aramid Kevlar® (DuPont) — are also polyamides but with aromatic rings in the backbone, giving them flame-resistant or ballistic properties at the cost of stiffness. They are not “nylon” in the everyday sense and do not appear on standard clothing labels as polyamide.
The fiber is melt-spun: solid polymer chips are melted, extruded through spinnerets to form filaments, drawn to align the chains, and heat-set. Cross-section can be circular, tri-lobal, or hollow. Common nylon trade names: Cordura® (high-tenacity nylon-66, Invista) for outdoor gear; Tactel®, Supplex®, Antron® (Invista) for apparel and carpets; ECONYL® (Aquafil) for recycled nylon-6 from depolymerized fishing nets and carpet waste; Robic® (Hyosung) for high-tenacity outdoor gear.
What is polyester (PET)?
Polyester in apparel almost always refers to polyethylene terephthalate (PET). The polymer was invented in 1941 in the United Kingdom by John Rex Whinfield and James Tennant Dickson at the Calico Printers’ Association (GB Patent 578,079). DuPont licensed the technology and began commercial U.S. production under the trade name Dacron in 1951. The British equivalent was Terylene.
A polyester is any polymer containing the -CO-O- (ester) linkage in its backbone. PET is produced by polycondensation of purified terephthalic acid (PTA) and monoethylene glycol (MEG), both petroleum-derived. The same polymer is used in beverage bottles, food containers, and films, which is why “polyester” and “PET plastic” share a polymer backbone. PET is FDA-approved for direct food contact under 21 CFR 177.1630. Legitimate concerns about polyester apparel relate to microfiber shedding, finishing chemistry, and microclimate humidity, not the inert polymer.
Bottle-grade PET and fiber-grade PET share the same polymer chain but differ in chain length and crystallinity: bottle PET has intrinsic viscosity (IV) around 0.80 dL/g via solid-state polymerization, fiber PET ~0.65 dL/g. Recycled fiber PET typically comes from depolymerized or melt-spun bottle flake (Scheirs & Long, Modern Polyesters, Wiley).
Other polyesters exist but are minor in apparel:
- PEN (polyethylene naphthalate) — higher heat resistance and barrier properties; used in industrial yarns, not apparel.
- PBT (polybutylene terephthalate) — bulkier and more elastic than PET; used in some carpet fibers and elastomeric blends.
- PLA (polylactic acid) — derived from corn or sugarcane; biodegradable under industrial composting; used in niche apparel.
Common trade names that map to engineered PET: Coolmax® and Thermolite® (Invista) for moisture-management activewear; Polartec® (Polartec, LLC) for fleece; Capilene® (Patagonia) for base layers; REPREVE® (Unifi) for recycled PET fiber. For more on rPET specifics — energy savings, shedding rates, and certifications — see the recycled polyester data review and the REPREVE® process detail.
Polymer family map: nylon ⊂ polyamide, PET ⊂ polyester
Each name refers to a specific subset of a larger polymer family:
| Family | Subfamily | Common members | Apparel/textile use |
|---|---|---|---|
| Polyamide (PA) | Aliphatic | Nylon-6, Nylon-66, Nylon-11, Nylon-12, Nylon-46 | Apparel, hosiery, ropes, carpets |
| Polyamide (PA) | Aromatic / semi-aromatic | Aramid (Kevlar®, Nomex®) | Ballistic, flame-resistant — not typical apparel |
| Polyester | Aromatic terephthalate | PET (polyethylene terephthalate) | >99% of “polyester” apparel |
| Polyester | Aromatic naphthalate | PEN (polyethylene naphthalate) | Specialty industrial — rare in apparel |
| Polyester | Aliphatic | PLA (polylactic acid) | Compostable apparel niche |
| Polyester | Aromatic terephthalate | PBT (polybutylene terephthalate) | Some technical fibers, elastomeric blends |
When a clothing label reads “100% polyamide,” the fiber is essentially always nylon-6 or nylon-66 — not Kevlar or Nomex. When it reads “100% polyester,” the fiber is essentially always PET — not PEN or PLA. The simplification “polyamide = nylon, polyester = PET” is correct in 99%+ of consumer apparel contexts.
How nylon and polyester compare: polymer-level data
Nylon and PET differ in nearly every measurable physical property. The values below are fiber-level — they describe the polymer in standard conditioning. Fabric performance depends additionally on yarn construction, weave or knit, weight (GSM), and finishes.
| Property | Nylon-6 | Nylon-66 | Polyester (PET) | Test method / source |
|---|---|---|---|---|
| Polymer family | Aliphatic polyamide | Aliphatic polyamide | Aromatic polyester | IUPAC nomenclature |
| Repeating linkage | -CO-NH- (amide) | -CO-NH- (amide) | -CO-O- (ester) | Chemistry textbook reference |
| Monomers | ε-caprolactam | Hexamethylenediamine + adipic acid | Ethylene glycol + terephthalic acid | Cook, Handbook of Textile Fibres Vol. 2 |
| Density (g/cm³) | 1.14 | 1.14 | 1.38 | ISO 1183 |
| Melt point (°C) | ~220 | ~265 | ~260 | DSC, ASTM D3418 |
| Glass transition Tg (°C) | ~47-50 (dry) | ~70 (dry) | 67-81 (dry; commonly cited ~70-80) | Hearle & Morton 2008; PET handbook data |
| Moisture regain at 65% RH, 20 °C (%) | 4.5 | 4.0 | 0.4 | Morton & Hearle 2008; ASTM D2654 |
| Tensile strength fiber (MPa) | 600-900 (standard); >1000 (high-tenacity) | 750-950; high-tenacity exceeds 1000 | 500-1100 depending on draw ratio and grade | Hearle & Morton 2008; manufacturer fiber data |
| Elongation at break (%) | 25-40 | 25-40 | 15-30 | ASTM D2256 |
| Year commercialized | 1939 (US, DuPont) | 1939 (US, DuPont) | 1941 invention (UK, Whinfield & Dickson) / 1951 US commercial introduction (DuPont Dacron) | GB Patent 578,079; US Patent 2,130,948 |
| Aquatic biodegradability | Persists for decades | Persists for decades | Persists for decades | Zambrano et al. 2019 |
Nylon is lighter (1.14 vs 1.38 g/cm³), holds an order of magnitude more moisture (4.0-4.5% vs 0.4%), and stretches more before breaking. PET is denser, drier, stiffer, and more thermally stable above ~220 °C. Nylon-66 measures slightly drier than nylon-6 because of its more crystalline structure.
How nylon and polyester compare: fabric-level performance
Fiber-level numbers translate into fabric behavior with several construction-dependent modifiers. The table below collects the most common test outputs for fabrics of equivalent denier and construction, with the standard test method and source for each row.
| Property | Nylon (typical fabric) | Polyester (typical fabric) | Test method / source |
|---|---|---|---|
| Wyzenbeek abrasion (high-tenacity weave) | 80,000+ double rubs | 30,000-60,000 double rubs | ASTM D4157 |
| Martindale abrasion (apparel weave) | typically high in PA66 | varies widely with weave/finish | ISO 12947 |
| UV strength loss (500 h Xenon arc, untreated) | up to 30% loss | typically <10% loss | ISO 4892-2 / ASTM G155; geotextile data per ASTM D4355 |
| Wet tensile strength change | -10 to -15% (recovers when dry) | <2% | Morton & Hearle 2008 |
| Dimensional change wet (uncoated) | +3 to 4% expansion | <0.5% | AATCC TM 135 / ISO 5077 |
| Hydrostatic resistance (uncoated) | Low | Low | AATCC 127 |
| Dyeing | Acid dyes (carboxyl-attacking) | Disperse dyes (high-temperature pressure) | AATCC 23, AATCC 169 |
| Polymer thermal conductivity (W/m·K) | 0.20-0.25 | 0.15-0.24 | polymer handbook data |
| Common GSM range (apparel) | 70-300 (varies with end use) | 70-300 (varies with end use) | manufacturer data |
The single largest practical gap between nylon and polyester at the fabric level is strength under abrasion: per ASTM D4157, high-tenacity ballistic nylon-66 weaves can exceed 80,000 double rubs while typical apparel polyester weaves at comparable yarn count run 30,000-60,000. The advantage scales with denier — a 1000D Cordura nylon ripstop will outlast a 600D polyester ripstop in friction-heavy applications. For lighter casual apparel (100-150 g/m² shirting), the gap matters less than dimensional stability and wash performance.
The second-largest gap is UV resistance: polyester loses well under 10% of its tensile strength after 500 hours of accelerated weathering under ISO 4892-2 (untreated), while untreated nylon can lose up to 30%. UV-stabilized nylon (with HALS additives) closes some of this gap, but does not eliminate it — which is why outdoor tents, sun-exposed luggage, and marine apparel often favor polyester despite nylon’s higher abrasion resistance.
Nylon resin typically trades at 1.5-2.5x the price of polyester resin per kilogram. Spot prices vary with petrochemical markets. For a longer comparison of polyester economics, see the cotton vs polyester price analysis.
Moisture: absorption, wicking, and what each fiber actually does
Cotton absorbs water into the fiber. Polyester repels water entirely. Nylon sits in between — and the difference matters for everything from athletic comfort to garment care.
Polyester (PET). PET is hydrophobic. The ester linkage offers very few hydrogen-bonding sites for water. Standard moisture regain at 65% RH, 20 °C is approximately 0.4% (Morton & Hearle, 2008; ASTM D2654). PET cannot absorb moisture into the fiber interior, but it can transport liquid water across inter-fiber spaces via capillary action — the mechanism behind “moisture-wicking” polyester. This requires engineered yarn cross-sections (tri-lobal, hollow), hydrophilic surface finishes, and open knit construction. AATCC Test Method 195 characterizes this behavior. Untreated, densely woven polyester does not wick at all — the fiber alone cannot move moisture, only its construction can.
Nylon (PA6, PA66). Nylon absorbs measurable water into the fiber via the amide -CO-NH- linkage’s hydrogen-bonding sites. Standard regain is 4.5% for nylon-6 and 4.0% for nylon-66. The fiber swells around 3-4% wet, with two consequences: (1) wet nylon temporarily loses 10-15% tensile strength as absorbed water disrupts inter-chain hydrogen bonds, and (2) wet nylon dries more slowly than wet polyester because the bound water has to evaporate from inside the fiber. When dry, the strength recovers fully.
The practical consequence of this 11x difference in regain is that nylon feels softer against skin in mild conditions because absorbed moisture moderates microclimate humidity. Polyester feels drier but can leave skin clammy in static conditions. For high-output activity polyester wins on speed of removal; for low-output everyday wear the choice is less clear-cut. The full breakdown of how moisture regain interacts with fabric construction is documented in the polyester vs cotton fiber-level comparison and the cotton vs polyester breathability lab data.
Dyeing: why nylon takes acid dyes and polyester takes disperse dyes
The two fibers also differ in how they accept color, which shows up as different colorfastness behavior in finished garments.
- Nylon has free amine end groups (-NH₂) on the polymer chain that can form ionic bonds with acid dyes — sulfonic and carboxylic acid dye chemistries. Acid dyeing is performed in acidic aqueous baths near 80-100 °C and produces strong, vivid colors with good wash fastness on nylon. The same dye chemistry also works on protein fibers (silk, wool) for the same reason.
- Polyester (PET) has no ionic dye sites. The polymer is too crystalline and too hydrophobic for water-based dyeing at atmospheric conditions. It is dyed with disperse dyes under high-temperature, high-pressure conditions (typically 130 °C in a pressurized vessel, or thermosol at 200+ °C). The disperse dye molecules diffuse into the polymer matrix between PET chains and are physically trapped there once the fiber cools.
A consequence: a 50/50 nylon/polyester blend cannot be dyed in a single bath with one dye class. Mixed-fiber fabrics either go through two-bath sequential dyeing (acid then disperse), or they use cross-dyeing techniques where each component picks up only part of the color. This is why two-tone nylon-polyester blends (visible in some athletic wear and outdoor gear) are intentional — the same dyeing run produces different colors on the two fiber components.
For consumers, the dyeing chemistry shows up in three places: (1) red and pink polyester garments are more prone to disperse-dye migration under heat, transferring color onto adjacent light fabrics; (2) acid-dyed nylon can lose color faster than disperse-dyed polyester under perspiration acid (sweat lowers fabric pH); (3) some disperse dyes (Disperse Blue 106, Disperse Blue 124, Disperse Yellow 3) are listed as skin sensitizers and restricted in OEKO-TEX Standard 100 (Disperse Yellow 3 is also restricted under EU REACH Annex XVII Entry 72). This is a finishing-chemistry concern, not a fiber concern.
How to tell nylon and polyester apart at home
For consumers without lab access, three practical methods identify a finished fabric.
1. Read the label. US and EU regulations (FTC Textile Fiber Products Identification Act, 16 CFR 303; EU Regulation 1007/2011) require fiber content disclosure. The label will read either “nylon,” “polyamide,” or “PA” for nylon, and “polyester” or “PES” for polyester. If both terms appear (“60% polyamide, 40% polyester”), the fabric is a blend and the percentages are mandated.
2. Hand feel and stretch. Nylon is silkier, smoother, and noticeably more elastic — it stretches further and recovers more from a stretch. Polyester is crisper, less elastic, and recovers less. A nylon swimsuit, a nylon pantyhose, and a nylon ski-base layer all share this characteristic stretch and silky surface. A polyester polo shirt and a polyester athletic tee feel firmer and more “dry.”
3. Burn test on a clipped sample. Destructive — only on a small clipped piece, over a non-flammable surface, with ventilation, never on a garment in active use. The differentiating signs:
| Observation | Nylon | Polyester (PET) |
|---|---|---|
| Smoke color | White-grey | Black, sooty |
| Smell | Celery, burnt hair, or wax | Sweet, chemical, slightly fruity |
| Flame behavior | Burns slowly, melts and drips | Burns with sooty flame, melts and drips |
| Residue | Hard tan-to-grey bead | Hard dark bead, harder to crush |
| Self-extinguishing | Often self-extinguishes when removed from flame | Often self-extinguishes when removed from flame |
The main differential is smoke color (white-grey vs black) and smell (celery vs sweet chemical). The burn test is also a reference fiber identification method in textile labs alongside microscopy and FTIR.
Common claims about nylon and polyester, reviewed
The nylon-vs-polyester SERP carries several plausible-sounding claims that do not survive contact with peer-reviewed evidence or standard nomenclature:
| Claim | Verdict | Why |
|---|---|---|
| ”The chemical name for polyester is polyethylene naphthalate” | False | The dominant commercial polyester in apparel is polyethylene terephthalate (PET), not polyethylene naphthalate (PEN). PEN is a separate, much rarer polyester used for industrial yarns. Source: ASTM D4275. |
| ”Nylon and polyester were both first produced by DuPont” | Half-false | Nylon was DuPont’s (US Patent 2,130,948). Polyester (PET fiber) was invented in the United Kingdom by Whinfield and Dickson at the Calico Printers’ Association in 1941 (GB Patent 578,079). DuPont licensed it and produced US “Dacron” from 1951. |
| ”Nylon was first introduced to the market in 1945” | False | DuPont nylon stockings hit the U.S. market on May 15, 1940. From 1942 to 1945, nylon was redirected to military parachute and rope production. 1945 was the resumption of civilian production, not the introduction. |
| ”Nylon’s wear resistance is 10x cotton, 140x wet viscose” | Unsupported folk-stat | Neither multiplier has a traceable origin study. Wet viscose is not a benchmark fiber for ASTM D3884 or ASTM D4157 abrasion testing, and ASTM/ISO abrasion results vary too widely with weave, denier, and finish for fiber-level multipliers to be meaningful. |
| ”Polyester impact strength can exceed nylon’s for sudden forces” | Misleading | Nylon’s higher elongation at break (25-40% vs polyester’s 15-30%) gives it larger area under the stress-strain curve — i.e., higher toughness — for sudden energy-absorbing loads. Why climbing rope, parachute fabric, and airbag fabric are nylon. Source: Hearle & Morton 2008. |
| ”Polyester is more breathable than nylon” | Misleading | ”Breathability” depends on weave, knit, denier, and finish — not the fiber. ISO 9237 air-permeability testing shows wide overlap between PET and nylon-6 fabrics of equivalent construction. |
| ”Nylon (or polyester) is hypoallergenic” | YMYL overreach | ”Hypoallergenic” has no FDA or EU regulatory definition for textiles. Reactions to synthetic fabrics typically trace to dyes (Disperse Blue 106, Disperse Blue 124 — listed under EU REACH Annex XVII) or formaldehyde-releasing finishes (restricted under OEKO-TEX Standard 100), not the polymer backbone. |
| ”Nylon is heat-resistant” | Half-false | Nylon is less heat-resistant than polyester. Nylon-6 melts at ~220 °C, nylon-66 at ~265 °C, PET at ~260 °C. The claim contradicts standard handbook melt points. |
| ”Recycled polyester (rPET) eliminates the microplastic problem” | False | rPET is chemically identical to virgin PET in the finished fiber and sheds microfibers at comparable rates per wash (De Falco et al. 2019). See the recycled polyester analysis for the energy-savings versus shedding trade-offs. |
| ”Nylon biodegrades faster than polyester because it absorbs water” | False | Both fibers are persistent in aquatic environments. Zambrano et al. (2019) showed that polyester and nylon microfibers do not biodegrade in marine or freshwater systems on relevant timescales. Nylon’s moisture regain (~4.5%) does not translate to environmental biodegradation. |
Microfiber shedding and recyclability
Both nylon and polyester shed microfibers during laundering. Both polymers are persistent in aquatic environments — Zambrano et al. (2019) confirmed in Marine Pollution Bulletin that synthetic fibers (polyester, nylon) do not biodegrade in marine or freshwater systems on relevant timescales, while cotton and rayon do.
Reported shedding rates vary by study and construction. Napper & Thompson (2016) reported approximately 496,030 fibers per typical 6 kg domestic wash load for polyester garments (the often-cited ~700,000 figure in that paper was for acrylic, not polyester; the acrylic value was 728,789). Hartline et al. (2016) showed shedding correlates with garment age, surface pilling, and wash mechanical action. De Falco et al. (2018, 2019) found shedding ranges of approximately 124-308 mg per kg of fabric per wash, with polyester woven structures shedding less per wash than polyester knits.
Recycling pathways differ between the two fibers:
- Recycled polyester (rPET) is the most mature recycled apparel fiber. Mechanical recycling shreds and remelts post-consumer PET bottles or fabric scraps; chemical recycling (depolymerization) restores virgin-equivalent properties at higher cost. Approximately 12% of global polyester production was rPET in 2024, down slightly from 12.5% in 2023 (Textile Exchange Materials Market Report 2024-2025). See the recycled polyester analysis for energy savings versus shedding trade-offs.
- Recycled nylon-6 is produced primarily by chemical depolymerization back to caprolactam, then repolymerization. ECONYL® (Aquafil) is the highest-profile commercial example, sourced from fishing-net waste, carpet waste, and industrial plastic. Nylon-66 depolymerization is harder due to its two-monomer structure and is less common at commercial scale; nylon-66 recycling is largely mechanical (chip remelting).
rPET infrastructure is larger and cheaper, but global recycled-nylon volumes are growing faster off a smaller base. Both are subject to the same microfiber-shedding concerns as their virgin counterparts.
When to choose nylon vs polyester
The data does not support a universal “nylon is better” or “polyester is better” answer. For 8h+ skin-contact garments, engineered polyester (Coolmax®, Capilene®, Dri-FIT, Polartec®) is still plastic with microfiber shedding (Napper & Thompson 2016; De Falco 2018, 2019); cotton, linen, merino wool, and lyocell/TENCEL™ are the primary choice — see the polyester vs cotton comparison.
| Use case | Nylon verdict | Polyester (PET) verdict | Recommended choice |
|---|---|---|---|
| Outdoor abrasion (backpacks, climbing gear) | Strong — high tensile, high abrasion | Mid — adequate abrasion, lower toughness | Nylon (Cordura® for high-tenacity applications) |
| Sun-exposed apparel (tents, sun-shirts) | Mid — UV-degradable without HALS treatment | Strong — high UV resistance | Polyester |
| Stretch garments (hosiery, swimwear, leggings) | Strong — high elongation, soft hand | Mid — less elastic | Nylon, often blended with elastane |
| Activewear running (high-output, fast-dry) | Mid — slower drying due to absorption | Strong — fast-drying with engineered wicking | Engineered polyester (Coolmax®, Capilene®) is a conscious athletic-performance choice — still plastic, with microfiber shedding per Napper & Thompson 2016. Merino wool is the natural alternative for moisture management without microplastic shedding |
| Activewear yoga/stretch | Strong — silky hand, recovery | Mid | Nylon-elastane blend for technical use; cotton-elastane or modal-elastane for non-competitive everyday wear |
| Casual everyday shirting (8–10h skin contact) | Mid — softer hand, holds wrinkles less than PET | Strong — wrinkle-resistant, fast-dry — but still plastic in 8h+ skin contact | First choice: 100% cotton or cotton-linen for daily wear (per the polyester vs cotton breakdown). Polyester or polyester-cotton blends (CVC 60/40, T/C 65/35) are informational mentions for budget or wrinkle-resistance priority, not a primary recommendation for daily skin-contact garments |
| Workwear / uniforms | Strong if abrasion priority; otherwise mid | Strong overall | Nylon (Cordura) for heavy-duty; polyester-cotton for lighter |
| Marine apparel / sailing | Mid — UV-vulnerable | Strong — UV- and water-stable | Polyester |
| Climbing rope / parachute fabric | Strong (toughness, energy absorption) | Weak (lower elongation, lower toughness) | Nylon |
| Outdoor tents (silnylon vs silpoly) | Strong wet-load (stretches and recovers) | Strong dry-load (UV-stable) — but tears more under wind | Application-specific (silnylon for stretch, silpoly for UV) |
| Recycled fiber availability | Growing (ECONYL®, recycled PA6) | Mature (rPET, REPREVE®) | Depends on which application |
| Cost-sensitive applications | Higher unit cost | Lower unit cost | Polyester |
| Garments often blended with elastane | Common in nylon-elastane | Common in polyester-elastane | Both — for the elastane contribution see what elastane fabric is made of |
For shirting where weave structure dominates the perceived feel of the garment, the comparison of plain weaves, basket weaves (oxford), and twills cuts across both fibers — see shirt fabric types and how weave changes performance independently of fiber.
For the broader question of how synthetic fibers in general compare against cotton (the dominant natural alternative), see the data-driven polyester vs cotton breakdown, which uses the same standardized test methods documented on the methodology page.
Summary: are nylon and polyester the same?
No. They are different polymer families with different chemistry and different performance profiles:
- Polymer. Nylon is a polyamide (-CO-NH-); polyester is most often PET (-CO-O-).
- Moisture. Nylon-6 holds ~4.5% moisture; PET holds 0.4%. Nylon swells when wet; PET does not.
- Strength. Nylon outperforms polyester on tensile strength, abrasion, and elongation/toughness. Polyester outperforms nylon on UV resistance, dimensional stability in water, and cost.
- Temperature. Nylon-6 melts at ~220 °C, nylon-66 at ~265 °C, PET at ~260 °C.
- Dyeing. Nylon takes acid dyes; polyester takes disperse dyes.
- Cost. Polyester is cheaper per kilogram by typically 1.5-2.5x.
- Recycling. rPET is more mature; recycled nylon (ECONYL®) is growing.
For garments worn against the skin 8+ hours per day, the synthetic-vs-synthetic comparison is secondary to the synthetic-vs-natural decision: see polyester vs cotton and the breathability lab data for the naturals-first framework.
Sources
Standards and regulations:
- ASTM D4157 — Standard Test Method for Abrasion Resistance of Textile Fabrics (Oscillatory Cylinder / Wyzenbeek). astm.org/d4157-13
- ASTM D2256 — Standard Test Method for Tensile Properties of Yarns by the Single-Strand Method. astm.org/d2256_d2256m-21
- ASTM D2654 — Standard Test Methods for Moisture in Textiles. astm.org/d2654-22
- ASTM D3418 — Standard Test Method for Transition Temperatures and Enthalpies of Fusion and Crystallization of Polymers by Differential Scanning Calorimetry. astm.org/d3418-21
- ASTM D737 — Standard Test Method for Air Permeability of Textile Fabrics. astm.org/d0737-18r23
- AATCC TM 135 — Dimensional Changes of Fabrics after Home Laundering. aatcc.org
- AATCC TM 195 — Liquid Moisture Management Properties of Textile Fabrics. aatcc.org
- ISO 12947-2 — Textiles: Determination of abrasion resistance of fabrics by the Martindale method. iso.org/standard/61058
- ISO 1183 — Plastics: Methods for determining the density of non-cellular plastics.
- ISO 4892-2 — Plastics: Methods of exposure to laboratory light sources (Xenon arc).
- ISO 9237 — Textiles: Determination of the permeability of fabrics to air.
- FTC Textile Fiber Products Identification Act, 16 CFR 303. ecfr.gov/title-16/part-303
- EU Regulation (EU) No 1007/2011 on textile fibre names and related labelling. eur-lex.europa.eu/eli/reg/2011/1007
- Carothers, W.H. (1937, granted 1938). U.S. Patent 2,130,948 — Synthetic fiber (linear condensation polyamide). patents.google.com/patent/US2130948
- Whinfield, J.R. & Dickson, J.T. (1941). GB Patent 578,079 — Improvements relating to the manufacture of highly polymeric substances (polyethylene terephthalate). patents.google.com/patent/GB578079A
Peer-reviewed studies:
- Hartline, N.L. et al. (2016) — “Microfiber Masses Recovered from Conventional Machine Washing of New or Aged Garments.” Environmental Science & Technology, 50(21), 11532-11538. doi.org/10.1021/acs.est.6b03045
- Napper, I.E. & Thompson, R.C. (2016) — “Release of synthetic microplastic plastic fibres from domestic washing machines: Effects of fabric type and washing conditions.” Marine Pollution Bulletin, 112(1-2), 39-45. doi.org/10.1016/j.marpolbul.2016.09.025
- De Falco, F. et al. (2018) — “Evaluation of microplastic release caused by textile washing processes of synthetic fabrics.” Environmental Pollution, 236, 916-925. doi.org/10.1016/j.envpol.2017.10.057
- De Falco, F. et al. (2019) — “The contribution of washing processes of synthetic clothes to microplastic pollution.” Scientific Reports, 9, 6633. doi.org/10.1038/s41598-019-43023-x
- Zambrano, M.C. et al. (2019) — “Microfibers generated from the laundering of cotton, rayon and polyester based fabrics and their aquatic biodegradation.” Marine Pollution Bulletin, 142, 394-407. doi.org/10.1016/j.marpolbul.2019.02.062
Reference books:
- Hearle, J.W.S. & Morton, W.E. (2008) — Physical Properties of Textile Fibres, 4th ed., Woodhead Publishing
- Cook, J.G. (2001) — Handbook of Textile Fibres, Vol. 2: Man-Made Fibres, 5th ed., Woodhead Publishing
- Scheirs, J. & Long, T.E. (2003) — Modern Polyesters: Chemistry and Technology of Polyesters and Copolyesters, Wiley
Brands and trade names:
- Invista — Cordura®, Tactel®, Supplex®, Antron®, Coolmax®, Thermolite®. invista.com
- Aquafil — ECONYL® regenerated nylon-6 from depolymerized fishing-net and carpet waste. aquafil.com
- Unifi — REPREVE® recycled polyester (rPET). unifi.com
- Hyosung — Robic® high-tenacity nylon. hyosung.com
- Polartec, LLC — Polartec® fleece. polartec.com
- Patagonia — Capilene® base-layer polyester. patagonia.com
- DuPont — original commercial nylon (1939) and Dacron polyester (1951 US licensing). dupont.com
- OEKO-TEX — Standard 100 restricted-substance list (disperse dye and formaldehyde-finish restrictions). oeko-tex.com