PVC properties
Polyvinyl chloride (PVC) is a low-cost amorphous thermoplastic, recognized for its high rigidity, resistance to acids and alkalis, and its inherent flame retardancy, with a maximum continuous service temperature around 60 °C / 140 °F. It comes in two main forms: rigid (unplasticized, PVC-U) and flexible (with plasticizers, PVC-P), which gives it a wide range of industrial applications.
Chemical composition
Section titled “Chemical composition”| Component / Characteristic | Value / Specification |
|---|---|
| Empirical formula | (C₂H₃Cl)ₙ |
| Typical elemental composition | 56.7 % Cl, 38.4 % C, 4.9 % H |
| CAS number | 9002-86-2 |
| Standard abbreviation | PVC |
| Polymer type | Amorphous thermoplastic |
| Appearance | White powder or granules, brittle (if no additives) |
| Odor | Odorless |
Mechanical properties
Section titled “Mechanical properties”The properties depend strongly on the formulation, particularly on the plasticizer content. Values for rigid PVC (PVC-U) and indicative ranges for flexible PVC (PVC-P) are shown below.
Rigid (PVC-U, unplasticized)
Section titled “Rigid (PVC-U, unplasticized)”| Property | Value |
|---|---|
| Tensile strength | 51 MPa / 7 395 psi |
| Flexural modulus | 3 GPa / 435 ksi |
| Elongation at break | 20–40 % |
| Strain at yield point | 3.5 % |
| Izod impact strength (notched) | 2–5 kJ/m² / 0.95–2.38 ft·lb/in |
| Rockwell surface hardness | RR110 |
Flexible (PVC-P, with plasticizer)
Section titled “Flexible (PVC-P, with plasticizer)”| Property | Typical range |
|---|---|
| Tensile strength | 10–21 MPa / 1 450–3 045 psi |
| Flexural modulus | 0.02–0.2 GPa / 2.9–29 ksi |
| Elongation at break | 150–400 % |
| Izod impact strength (notched) | No break (NB) in standard thicknesses |
Physical properties
Section titled “Physical properties”| Property | Value |
|---|---|
| Density | 1.4 g/cm³ / 87.4 lb/ft³ |
| Water absorption (24 h, ASTM) | 0.1 % |
| Molding shrinkage | 0.4 % |
| Limiting oxygen index (LOI) | 45 % |
| UL94 flammability rating | V-0 |
Thermal properties
Section titled “Thermal properties”| Property | Value |
|---|---|
| Glass transition temperature (Tg) | 82 °C / 180 °F |
| Melting range (processing) | 150–220 °C / 302–428 °F |
| Heat deflection temperature (HDT, 0.45 MPa) | 70 °C / 158 °F |
| Heat deflection temperature (HDT, 1.80 MPa) | 67 °C / 153 °F |
| Maximum continuous service temperature | 60 °C / 140 °F |
| Coefficient of linear thermal expansion | 6 × 10⁻⁵ /°C / 3.3 × 10⁻⁵ /°F |
| Specific heat (c) | 0.9 kJ/(kg·K) / 0.215 BTU/(lb·°F) |
| Effective heat of combustion | 17.95 MJ/kg / 7 720 BTU/lb |
Electrical properties
Section titled “Electrical properties”| Property | Value |
|---|---|
| Dielectric strength | 40 MV/m / 40 kV/mm / 1 016 V/mil |
| Volume resistivity | 10¹⁴ Ω·cm |
| Dielectric constant at 1 kHz | 3.1 |
| Dissipation factor at 1 kHz | 0.025 |
Applications by industry
Section titled “Applications by industry”- Construction: pipes for cold water and drainage, window profiles, cladding, gutters and downpipes.
- Packaging: bottles for non-food products, shrink films, blisters and caps.
- Electrical and electronics: cable insulation in plasticized or crosslinked formulations when low flammability is required.
- Consumer products: phonographic records, bank cards, shoe soles, textile coatings.
- Medical sector: flexible tubes for serums and blood products, fluid storage bags.
- Automotive: weatherstrip profiles, anticorrosion coatings on underbodies (plastisols).
Comparison with similar materials
Section titled “Comparison with similar materials”| Material | Density (g/cm³) | Tensile strength (MPa / psi) | Flexural modulus (GPa / ksi) | Max. service temp. (°C / °F) | Chemical resistance | Relative cost |
|---|---|---|---|---|---|---|
| PVC-U (rigid) | 1.4 / 87.4 lb/ft³ | 51 / 7 395 | 3 / 435 | 60 / 140 | Good to acids and bases | Low |
| CPVC (chlorinated) | 1.55 / 96.7 lb/ft³ | 55 / 7 975 | 3.2 / 464 | 93 / 200 | Very good, even at high temperatures | Medium |
| PP (polypropylene) | 0.90 / 56.2 lb/ft³ | 30–40 / 4 350–5 800 | 1.2–1.5 / 174–218 | 100 / 212 | Excellent to many solvents, less to oxidants | Low |
| HDPE (high-density polyethylene) | 0.95 / 59.3 lb/ft³ | 20–30 / 2 900–4 350 | 0.8–1.0 / 116–145 | 80 / 176 | Very good to acids and bases, sensitive to hydrocarbons | Low |
Frequently Asked Questions (FAQ)
Section titled “Frequently Asked Questions (FAQ)”What is the difference between rigid PVC (PVC-U) and flexible PVC (PVC-P)?
Section titled “What is the difference between rigid PVC (PVC-U) and flexible PVC (PVC-P)?”PVC-U has a tensile strength around 51 MPa / 7 395 psi and an elongation of 20–40 %, while PVC-P, by incorporating plasticizers, reduces its strength to 10–21 MPa / 1 450–3 045 psi and increases elongation to above 150 %, sacrificing rigidity in exchange for high flexibility.
Can PVC be used in hot water installations?
Section titled “Can PVC be used in hot water installations?”Not recommended, since its maximum continuous service temperature is 60 °C / 140 °F and above 80 °C / 176 °F it suffers significant loss of mechanical strength. For hot water, CPVC is used, which withstands up to 93 °C / 200 °F.
What does PVC-U mean?
Section titled “What does PVC-U mean?”The “U” stands for “unplasticized”. PVC-U is the rigid version, which maintains an Izod impact strength of 2–5 kJ/m² (0.95–2.38 ft·lb/in) and a flexural modulus of 3 GPa / 435 ksi, being ideal for structural applications.
Is PVC a flame-retardant material?
Section titled “Is PVC a flame-retardant material?”Yes, it is intrinsically flame retardant due to its high chlorine content. It has a limiting oxygen index of 45 % and UL94 V‑0 rating, meaning it self‑extinguishes when the flame is removed.
How do UV rays affect PVC?
Section titled “How do UV rays affect PVC?”Rigid PVC has good resistance to UV radiation, although prolonged exposure can cause surface discoloration. For outdoor applications, UV stabilizers or pigments (e.g., TiO₂) are often added, extending its service life beyond 10–15 years without significant mechanical loss.
Is PVC recyclable?
Section titled “Is PVC recyclable?”Yes, PVC is a fully recyclable thermoplastic, with a constant density of 1.4 g/cm³ that facilitates separation by flotation. Established streams exist for recycling both post‑industrial and post‑consumer PVC, and the recycled material can be reintroduced into new products without significantly compromising its properties if thermal degradation is controlled.
Sources Consulted
Section titled “Sources Consulted”- azom.com: https://www.azom.com/article.aspx?ArticleID=770
- engineeringtoolbox.com: https://www.engineeringtoolbox.com/pvc-cpvc-pipes-dimensions-d_795.html
- steelnumber.com: https://www.steelnumber.com/en/steel_composition_eu.php?name_id=199