PVC Plastic Properties — Mechanical, Chemical, and Thermal Data

PVC plastic properties vary substantially across grades. Type 1 PVC leads on tensile strength and chemical resistance; Type 2 trades both for impact toughness; CPVC extends thermal capability to 200°F while matching Type 1's tensile strength; Expanded PVC is a structural substrate, not a load-bearing material. This page compiles the critical mechanical, chemical, thermal, and electrical data engineers and buyers need to specify the correct grade.

At a glance:

• Type 1 PVC tensile strength: 7,500 psi — highest in the PVC family
• CPVC continuous use temperature: 200°F (93°C) vs. 140°F (60°C) for rigid PVC
• Type 2 PVC Izod impact: 2.0+ ft-lb/in; Type 1 is 0.4 ft-lb/in (brittle)
• All rigid PVC grades: UL 94 V-0 inherent flame rating
• PVC resists most inorganic acids, bases, and salt solutions; avoid ketones, THF, and aromatic solvents
• CPVC density is 1.55 g/cc — heavier than Type 1 (1.40) due to additional chlorination

Mechanical Properties

Mechanical properties reflect ASTM D638 (tensile), D790 (flexural), D256 (impact), and D695 (compressive) test methods. Values below are representative of commercially available extrusion-grade material tested at 73°F (23°C).

Type 1 vs. Type 2: What the Impact Data Means

An Izod impact value of 0.4 ft-lb/in classifies Type 1 PVC as a brittle material under notched testing conditions. In practice, unnotched panels tolerate moderate handling, but stress concentrations — drilled holes, sharp internal corners, machined grooves — can initiate fracture under mechanical loading. Design with generous corner radii (minimum 1.5× wall thickness) and avoid pressed-fit fasteners in Type 1 PVC.

Type 2's impact value of 2.0–5.0 ft-lb/in is not a trivial improvement. It reflects the rubber-toughening phase that arrests crack propagation. The material still deflects elastically before yielding, but the failure mode shifts from sudden fracture to ductile deformation. For any application where shock loads or vibration are present, the additional cost of Type 2 stock is offset by reduced failure risk.

CPVC Stiffness Premium

CPVC has a slightly higher flexural modulus than Type 1 — 420,000 vs. 400,000 psi — because the additional chlorination increases chain stiffness. At elevated temperatures, the stiffness advantage of CPVC over Type 1 is pronounced: near 140°F, Type 1 PVC approaches its service limit and stiffness drops significantly, while CPVC retains most of its room-temperature modulus up to approximately 180–190°F.

Thermal Properties

Continuous Use Temperature vs. Vicat Softening Point

The 140°F continuous use rating for Type 1 PVC is a conservative operating guideline that accounts for long-term creep, retained strength, and joint integrity. The Vicat softening point (185°F) marks where the material begins to deform under a defined load — not a safe operating temperature. Design engineers should use the 140°F figure for sustained loads in warm environments. Brief excursions to 160–165°F are generally acceptable if loads are minimal, but they should not be routine.

CPVC's 200°F continuous rating and 215°F HDT give meaningful headroom for hot process lines. When handling hot acids (concentrated sulfuric, hydrochloric at elevated temperatures) or hot caustic above 140°F, CPVC is the standard upgrade from Type 1.

Chemical Resistance

PVC's chemical resistance profile is one of its primary selling points. The chlorinated backbone resists hydrolysis and is inert to most aqueous acid and base solutions at ambient temperature. Resistance degrades at elevated temperature and with concentrated oxidizing species.

Resistance rating key: E = Excellent (no measurable effect), G = Good (minor effect, suitable for most service), F = Fair (use with caution, evaluate at service conditions), NR = Not Recommended

This table reflects general industry consensus. Always conduct immersion testing at actual service temperature, concentration, and stress before committing to a final design. Data for polypropylene chemical resistance and PVDF/Kynar resistance are available for comparison where PVC may be borderline.

Electrical Properties

PVC is a good electrical insulator across a wide frequency range. These properties make rigid PVC suitable for electrical conduit bodies, wireway housings, and enclosures exposed to chemical splash.

Physical and Optical Properties

PVC absorbs very little moisture (0.05% for Type 1) compared to nylons (8–9%) or acetal (0.2%). This dimensional stability benefits precision-machined components where moisture swelling would alter fit. Parts machined from PVC sheet maintain tolerance through ambient humidity cycles.

Comparing PVC Properties to Competing Materials

Engineers evaluating PVC against alternatives should note:

• vs. Polypropylene: PVC is stiffer (400K vs. 200–260K psi flexural modulus), heavier, and more resistant to inorganic acids. PP has better solvent resistance (aromatic solvents, ketones) and lower density. For how polypropylene compares directly to PVC, see the full comparison.
• vs. ABS: ABS offers higher impact strength and better cosmetics for appearance parts, but its chemical resistance is dramatically lower — ketones, esters, and aromatics attack ABS rapidly.
• vs. PVDF/Kynar: PVDF handles oxidizing acids, halogens, and temperatures to 260°F — all beyond PVC's capability. PVDF carries a 5–8× price premium per pound. See PVDF/Kynar properties for detail.

Related Guides

More related guides

Cross-cluster suggestions to help shoppers and engineers explore adjacent topics:

Applications

• Manifolds
• Chemical Tanks
• Marine Outdoor

Industries

• Marine
• General Industrial

Compare to other materials

• Pvc Vs. Polypropylene
• Pvc Vs. Abs
• Pvc Vs. Pvdf

Frequently asked questions — Pvc FAQ