PVDF Kynar Sheet & Rod — Chemical-Resistant Plastic Guide

PVDF (polyvinylidene fluoride), sold under the Kynar brand by Arkema and as Solef by Solvay and Neoflon by Daikin, is a semi-crystalline fluoropolymer engineered for aggressive chemical environments where rigidity and weldability matter. Available in sheet and rod stock, PVDF handles continuous service at 300°F (149°C), resists most acids, halogens, and solvents, and carries an inherent UL 94 V-0 flame rating — all without requiring additives. For engineers specifying chemical-processing equipment, semiconductor wet-bench components, or ultra-pure water systems, PVDF delivers performance that softer fluoropolymers like PTFE cannot match at equivalent wall thicknesses. It is not the cheapest option in any comparison, but in the applications where it is specified, no lower-cost material survives the service environment without significant compromise.

At a Glance

• Continuous use temperature: 300°F (149°C)
• Tensile strength: 7,000 psi — significantly stiffer and stronger than PTFE
• Flexural modulus: ~290,000 psi
• Density: 1.78 g/cc
• Flame rating: UL 94 V-0, inherently flame retardant, low smoke
• Resistant to most mineral acids, halogens, chlorinated solvents, and oxidizing agents
• Weldable by hot-gas and butt-fusion methods — a major advantage over PTFE
• Available as natural (off-white) sheet and rod; FDA 21 CFR 177.2510 compliant

What Is PVDF / Kynar?

Polyvinylidene fluoride is a partially fluorinated thermoplastic — the polymer backbone alternates CH₂ and CF₂ groups, giving PVDF a unique combination of fluoropolymer chemical inertness and the processability of a semi-crystalline engineering thermoplastic. Unlike fully fluorinated PTFE, PVDF can be melt-processed, welded, and machined to tighter tolerances, making it practical for fabricated assemblies. The semi-crystalline structure — typical crystallinity 50–60% for homopolymer grades — drives both the mechanical stiffness and the chemical resistance: crystalline domains resist chemical permeation while the amorphous phase contributes ductility and processing flexibility.

Fluoropolymer Family Context

PVDF sits between PTFE and engineering plastics in the fluoropolymer spectrum. PTFE offers the broadest chemical resistance but is soft, creep-prone, and cannot be welded. PVDF trades some of that absolute chemical breadth for substantially higher modulus and the ability to form leak-free welded joints. For tanks, pipes, fittings, and wet-bench components where pressure and structural loads are present, PVDF is almost always the preferred fluoropolymer.

Key Manufacturers and Tradenames

Stock shapes sold under the generic "PVDF" designation typically use homopolymer resin. For application-critical work, confirm the specific grade with your supplier.

Properties Overview

PVDF's performance profile is defined by four pillars: mechanical strength, thermal stability, chemical resistance, and electrical behavior.

Mechanical Strength

With a tensile strength of 7,000 psi and flexural modulus near 290,000 psi, PVDF is roughly three to five times stiffer than unfilled PTFE. This stiffness makes PVDF practical for unsupported panels, tank walls, and structural manifolds — geometries where PTFE would creep under sustained load. Compressive strength is similarly high, and PVDF retains meaningful mechanical properties up to its rated continuous use temperature.

Thermal Stability

PVDF is rated for continuous service at 300°F (149°C). Intermittent excursions to 320–330°F (160–165°C) are possible, but sustained exposure above the rated limit will soften the part and accelerate creep. Below its service range, PVDF remains useful down to approximately -40°F (-40°C) without embrittlement, a useful characteristic for outdoor or cryogenic-adjacent applications.

Chemical Resistance

PVDF's chemical resistance is exceptional against inorganic acids (hydrochloric, sulfuric, nitric, hydrofluoric), halogens (chlorine, bromine, fluorine gas), and oxidizing agents — the chemical environment that destroys many engineering thermoplastics. It resists chlorinated solvents better than most non-fluorinated plastics. Its primary limitations are strong bases such as concentrated caustic soda and specific polar solvents (dimethylformamide, acetone at elevated temperature). Always verify the specific concentration and temperature against a chemical resistance table before specifying.

Electrical Properties

PVDF is piezoelectric and pyroelectric, properties exploited in sensor films but generally irrelevant for structural stock shapes. Its dielectric constant (~8.4 at 1 kHz) is higher than PTFE, which matters for RF applications but not for typical chemical-processing or semiconductor use cases.

For detailed mechanical and chemical property data, see the PVDF properties guide.

Grades

Three grade categories cover the vast majority of PVDF stock-shape applications:

Standard PVDF (Homopolymer)

General homopolymer PVDF is used where broad chemical resistance and moderate fabrication requirements apply. It is the default starting point for most chemical-processing and semiconductor applications.

Kynar 740 (High-Performance Homopolymer)

Kynar 740 is Arkema's highest-purity, highest-molecular-weight homopolymer. It provides the best available chemical resistance, maximum use temperature, and lowest extractables — critical for semiconductor ultrapure water (UPW) systems and applications where trace ionic contamination is unacceptable.

Kynar Flex (Copolymer with HFP)

Kynar Flex copolymers incorporate hexafluoropropylene (HFP) into the backbone to reduce crystallinity. The result is a softer, more flexible material that forms welds more easily and resists cracking under flex stress. Kynar Flex is preferred for tubing, flexible liners, and any assembly where the geometry is complex enough that brittleness at weld joints would be a concern.

Detailed grade selection guidance is in the PVDF grades page.

Applications

PVDF's combination of chemical resistance, rigidity, and weldability makes it the first-call fluoropolymer for fabricated structures in aggressive environments.

Chemical Processing Equipment

PVDF sheet is routinely fabricated into acid tanks, fume scrubber bodies, pump housings, valve bodies, and pipe manifolds that handle HCl, H₂SO₄, HNO₃, and halogenated process streams. The material's high modulus allows thinner-than-PTFE walls without sacrificing structural integrity, and its weldability enables leak-tight fabricated assemblies without mechanical fasteners through wetted zones.

Semiconductor Wet Process

The semiconductor industry relies on PVDF and Kynar 740 for wet-bench components, chemical distribution lines, etch tanks, and rinse stations. High-purity grades maintain extremely low ionic extractables, protecting wafer cleanliness throughout HF, H₂O₂, H₂SO₄/H₂O₂ (piranha), and SC-1/SC-2 cleaning steps. PVDF is specified in SEMI standards for semiconductor chemical handling precisely because it combines chemical compatibility with mechanical robustness.

Ultra-Pure Water (UPW) Systems

UPW piping and tanks at semiconductor fabs, pharmaceutical plants, and power generation facilities specify PVDF for its low extractables and resistance to the aggressive hot-water and ozonated water used to maintain ultra-low total organic carbon (TOC). Kynar 740 is the preferred grade where parts-per-trillion contamination targets apply.

Photovoltaic Backsheet

PVDF film and coatings serve as the weathering layer on photovoltaic (PV) module backsheets. Its UV resistance, electrical insulation, low moisture permeability, and long outdoor durability meet the 25-year service life requirement for solar panels. While not a stock-shape application, it illustrates the breadth of the PVDF material platform.

Full application details: PVDF applications.

Stock Specifications

PVDF sheet is stocked in 4′ × 8′ format across a range of thicknesses, and PVDF rod runs from 1/4″ through 4″ diameter. Natural (off-white) is the standard color. Custom colors are rarely offered and typically require minimum order quantities.

Sheet Thicknesses (Standard Stocked)

Common stocked thicknesses: 1/8″, 3/16″, 1/4″, 3/8″, 1/2″, 3/4″, 1″, 1-1/2″, 2″. Thicker slab stock is available on inquiry.

Rod Diameters (Standard Stocked)

Standard diameters: 1/4″, 3/8″, 1/2″, 3/4″, 1″, 1-1/4″, 1-1/2″, 2″, 2-1/2″, 3″, 4″. Rod is typically cut to length from 4′ or 6′ lengths.

Full size charts, tolerances, and standard specifications: PVDF specifications.

Weight and Handling

At a density of 1.78 g/cc, PVDF is noticeably heavier than polypropylene (0.91 g/cc) and HDPE but lighter than PTFE (2.20 g/cc). A standard 4 × 8 × 1/2″ sheet weighs approximately 47 lbs. For large tanks or assemblies fabricated from multiple panels, structural support and rigging considerations must account for PVDF's density — it is not as light-handleable as PP tanks of equivalent size.

Machining and Fabrication

PVDF machines well on conventional metalworking equipment with minor adjustments. Key points:

• Use sharp, positive-rake tools with slow to moderate feed rates to avoid chatter and heat buildup
• Dry cutting is acceptable; coolant (water or air) improves surface finish on precision cuts
• PVDF is weldable by hot-gas welding and butt-fusion — this sets it decisively apart from PTFE
• Dimensional tolerances achievable: ±0.005″ on most turned and milled features

Weldability is PVDF's most significant fabrication advantage. Tanks, manifolds, and complex flow paths can be built from flat sheet and welded rod stock without adhesives or mechanical joints in the wetted zone — critical in semiconductor and chemical-processing applications where contamination and leak integrity are paramount.

For tooling specs, feeds, speeds, and welding procedures: PVDF machining guide.

FDA and Purity Compliance

PVDF (Kynar) complies with FDA 21 CFR 177.2510 for repeated food contact use, making it suitable for food-contact equipment components in processing environments that demand chemical-resistant plastics. NSF listings apply to specific compounded grades; verify the specific lot or grade against NSF certification databases for drinking water contact.

Semiconductor-grade Kynar 740 is specified to SEMI standards and meets the extractables requirements of the most demanding UPW and chemical distribution applications.

More detail: PVDF FDA and food-grade compliance.

How PVDF Compares

PVDF competes primarily with PTFE on the high end and polypropylene or PVC on the cost-sensitive end. Understanding where each material’s operating envelope ends is the fastest way to narrow a material selection decision. Cost alone should not drive the choice — a failed tank or a contaminated UPW system costs orders of magnitude more than the premium between polypropylene and PVDF.

• PVDF vs PTFE: PVDF is stiffer, weldable, and dimensionally more stable. PTFE covers a broader chemical range (especially strong bases) but is soft, creep-prone, and cannot be welded. For structural chemical-processing components, PVDF is usually the better choice. See the PTFE vs PVDF comparison.
• PVDF vs Polypropylene: PP is far less expensive but limited to ~200°F and weak against many solvents and oxidizing acids. PVDF justifies its cost premium in any application where PP's chemical or thermal limits are approached.
• PVDF vs PVC: PVC is economical but rated only to ~140°F and is not resistant to halogens or strong oxidizing acids. In aggressive chemical environments, PVDF replaces PVC when temperature or chemistry exceeds PVC's limits.

Full side-by-side analysis, including cost context and application decision rules: PVDF comparisons index.

Get PVDF / Kynar Sheet and Rod

FedMat stocks PVDF / Kynar sheet and rod in natural color in standard and non-standard thicknesses. Request a quote at the link above or contact our materials team with your dimensions, grade preference (standard PVDF, Kynar 740, or Kynar Flex), and quantity.

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Frequently asked questions — Pvdf Kynar FAQ