kynar

KYNAR

Chemical resistance tables

BDI MW 005680/01 -hemical resistance tables of Kynar® 2

KYNAR


Index

Page numbers

1. General Introduction 3

2. Resistance criteria – Standards 4 to 5

3. KYNAR® - General resistance table 6 to 13

4. KYNAR® - Long term ageing and stress resistance behaviour 14 to 17

5. SOLVENTS for KYNAR® PVDF 18

6. Resistance of KYNAR® PVDF to BASES and ALKALIS 19 to 21

7. Resistance of KYNAR® PVDF to CHLORINE 22 to 23

8. Resistance of KYNAR® PVDF to SULFURIC ACID 24 to 25

9. Resistance of KYNAR® PVDF to BROMINE 26 to 27

10. Chemical resistance of KYNAR FLEX® PVDF copolymers 28 to 30

11. Permeability properties of KYNAR® PVDF 31 to 36

12. Comparison of chemical resistance of KYNAR® PVDF with other

thermoplastic materials used in the chemical process industry 3 The information contained in this document is based on trials carried out by our Research Centres and data selected from the literature, but shall in no event be held to constitute or imply any warranty, undertaking, express or implied commitment from our part. Our formal specifications define the limit of our commitment. No liability whatsoever can be accepted by ARKEMA with regard to the handling, processing or use of the product or products concerned which must in all cases be employed in accordance with all relevant laws and/or regulations in force in the country or countries concerned.

Technical Polymers Division 420, rue d’Estienne d’Orves - 92705 Colombes (France) Tel. (33) 01 49 00 80 80 - Téléfax (33) 01 49 00 83 96


1. Introduction

KYNAR® polyvinylidene fluoride (PVDF), the homopolymer of 1,1-difluoroethylene, is a tough

engineering thermoplastic. The unique structure of alternating methylene and difluoromethylene

units along the chain creates a polymer material having high crystallinity combined with a high

polarity resulting in sharp melting point. Thus KYNAR® PVDF has the characteristic stability of

fluoropolymers when exposed to harsh thermal, chemical and ultraviolet environments while

retaining the properties of a conventional thermoplastic material. KYNAR® PVDF can readily be

processed by all known extrusion and molding processes.

� Important properties of KYNAR® PVDF : • Mechanical strength and toughness • High abrasion resistance • High thermal stability • Very low creep • High dielectric strength • High purity • Readily melt processable • Exceptional outdoor weather resistance due to its total inertness to UV

radiation

• Resistance to nuclear radiation • Resistance to fungi • Very smooth surfaces can be obtained • Low permeability to most gases and liquids • Low flame and smoke characteristics • Rigid and FLEX ible versions available

KYNAR®, Polyvinylidene difluoride, offers very good chemical resistance in the presence of a wide

variety of different chemicals up to high temperatures of approximately 150°C:

� KYNAR® resists well : - to acids

- to salt solutions

- to oxydants

- to halogens

- to alcohols

- to chlorinated solvents

- to aliphatic hydrocarbons

- to petrol

� At higher temperatures KYNAR® is

attacked by :

- amines

- concentrated sulfuric or nitric acid

- alkaline solutions of intermediate

concentration

� KYNAR® swells in certain polar

solvents : - ketones

- esters

� The following solvents dissolve

KYNAR® :

- Dimethyl acetamide (DMA)

- Dimethyl formamide (DMF)

- N-methyl pyrrolidone (NMP)


2 Resistance criteria - Standards

The following tables show results based on short time scale trials. These laboratory tests allow to

screen a great number of chemicals of which sensitive chemicals have been further investigated.

The tests have been undertaken as follows:

- Tensile specimens according to the standard ASTM 3222-73 and injected sheets are immersed

into the indicated chemical.

- After 7 days of immersion the samples are tensile tested according to the standard ASTM D

638 and the obtained values compared to the values of non exposed samples.

- Swelling measurements are performed on the injected sheets according to the standard

ASTM D 543.67.

� The judgement on chemical resistance is based on the standard ISO 4433.

It is based on:

- variation of weight

- surface aspect

- coloration

- mechanical properties (stress at yield , elongation at break)

+ « resistant » or « satisfactory », if

0 « partial or limited resistance », if

- « not resistant or not satisfactory resistance », if

- 2 % ≤ ∆ m ≤ + 10 % and Q ≥ 80 % and

εR2 ≥ 0,9 εS1 and εS2 ≤ 2 εS1

- 2 % ≤ ∆ m ≤ + 10 % and 80 % > Q > 46 % and

εR2 ≥ 0,9 εS1 and εS2 ≤ 2 εS1

or - 2 % ≤ ∆ m ≤ + 10 % and

Q ≥ 80 % and εS1 ≤ εR2 ≤ 0,9 εS1 and

εS2 ≤ 2 εS1

∆ m > 10 % or ∆ m < -2 % Q ≤ 46 % and

εR2 ≥ 0,9 εS1 and εS2 ≤ 2 εS1

or - 2 % ≤ ∆ m ≤ + 10 % and 80 % > Q > 46 % and

εS1 ≤ εR2 ≤ 0,9 εS1 and εS2 ≤ 2 εS1

Q = σS2 / σS1 index 1 = reference sample index 2 = aged sample

∆ m = mean of relative weight change σS = mean value of tensile stress at yield

εs = mean value of elongation at yield εR = mean value of elongation at break

It should be noted that this classification does not yet take into account the resistance under

mechanical load, such as the pressure bearing of a pipe.

For this type of resistance additional tests have to be done. In this brochure the long term ageing

tests done with applied stress give information on this subject.


2 Resistance criteria - Standards

� Classification based on the factor Q

A simplified approach, which allows chemical compatibility estimations by following the weight

change only, has been established by the German Institut für Bautechnik (Institute for construction

and building). There it was found that it exists a straightforward relation between weight change and

modulus evolution during immersion testing.

7 14 28 56 112 365 73010

100

Days

Q -

val

ue

+

0

-

0

500

1000

1500

2000

2500

0 5 10 15 20 25

change of weight (%)

E m

odul

us (

MP

a)


Chapter 3

KYNAR®

General chemical resistance table

This table designed to serve as a general guide to the chemical compatibility performance of

KYNAR® PVDF has been based mainly on laboratory experiments, in particular immersion tests

with at least 30 days observation time. The performance criteria have been described in chapter 2.

Many important chemicals have been tested for considerable longer time scales. These results are

described in chapter 4. In separate chapters 5, 6, 7, 8 and 9 particular chemicals are reviewed in

detail and their chemical action leading to compatibility limits described. Whenever possible, field

trials and observations are included.

The results in the General chemical resistance table refer to the chemical compatibility of

KYNAR® PVDF itself. The performance of equipment where KYNAR® PVDF is used for

corrosion protection depends on the entire design. For instance, permeation of chemical species can

reduce the temperature rating of the equipment design to a lower value than that for KYNAR®

PVDF.

Use of the table :

A drawn arrow signifies the classification « + ».

A dotted arrow signifies the classification « 0 ».

The sign « ✕« signifies the classification « - ».


3 - KYNAR® - General chemical resistance table

� Mineral Acids Conc. 25° 50° 75° 100° 125° 150°

� Boric acid saturated � Hydrobromic acid 50% � Hydrochloric acid concentr. /35% � Hydrochloric acid gas � Cyanic acid 100% � Hydrofluoric acid 40% � Hydrofluoric acid 70% � Hydrofluoric acid 100% � Nitric acid 30% � Nitric acid 65% � Perchloric acid 70% � Phosphoric acid 85% � Phosphoric acid 98% � Sulfuric acid 50% � Sulfuric acid 80% � Sulfuric acid 93% � Sulfuric acid 98% � Hydrogen sulfide � Chlorsulfonic acid 98% � Fluorosulfonic acid 97% � Fluorosilicic acid � Mixtures of Mineral Acids Conc. 25°C 50° 75° 100° 125° 150°

� Sulfuric / nitric (1 / 1) 40% � Nitric / Hydrochloric (1 / 3) 100% � Phosphochromic :

- phosphoric 80%

- Chromium trioxide 5%

- Sulfuric 3%

� Sulfochromic : - Sulfuric 15%, Water 35%

- Chromium trioxide 50%

� Anhydrides and chlorides

of Mineral Acids Conc. 25° 50° 75° 100° 125° 150°

� Chromic anhydride saturated � Chromic anhydride 60% � Phosphore trichloride 100% � Phosphor pentachloride 100% ✕ � Phosphoroxy trichloride 100% � Thionyl chloride 100% � Sulfuric anhydride 100% � Sulfuryl chloride 100%



� Mineral Bases *please refer also to chapter 6

Conc. 25° 50° 75° 100° 125° 150°

� Ammonia gas � Ammonia solution 30% � Potassium hydroxide 50% � Sodium hydroxide 45% � Sodium hydroxide 60% � Mineral salts Conc. 25° 50° 75° 100° 125° 150°

� All types of neutral or

acidic mineral salts in

solution up to saturation

� Titanium tetrachloride 100% � Boron trifluoride 100% � Elements Conc. 25° 50° 75° 100° 125° 150°

� Bromine dry � Bromine humid � Chlorine dry -no UV � Chlorine Humid

no UV

� Chlorine with UV ✕ � Fluorine � Hydrogen � Iodine � Mercury � Oxygen � Ozone gas (2%) � Ozone solution � Sulfur



� Organic acids Conc. 25° 50° 75° 100° 125° 150°

� Acetic acid 100% � Acetic acid 50% � Acrylic acid � Benzene sulfonic acid concentr. � Benzoic acid satur. � Chloro-acetic acid 75% � Chloro-acetic acid 100% � Citric acid 50% � Formic acid 98% � Gallic acid satur. � Glycolloic acid satur. � Lactic acid (2-hydroxy-

propanoic)

50%

� Lauric acid (dodecanoic) 100% � Linoleic acid (9,12-

octadecadieneoic)

100%

� Maleic acid satur. � Malic acid satur. � Methane sulfonic acid 50% � Oleic ac. (9-octadecenoic ) 100% � Oxalic acid satur. � Palmitic acid 100% � Phtalic acid satur. � Picric acid (2,4,6 trinitro-

phenol)

10%

� Salicylic acid 50% � Stearic acid satur. � Tartric acid satur. � Trichloro-acetic acid 50% � Trichloro-acetic acid 100% � Anhydrides and chlorides

of Organic acids Conc. 25° 50° 75° 100° 125° 150°

� Acetic anh. 100% � Acetic acid chloride 100% � Chloro-acetic acid chloride 100% � Benzoyl chloride 100% � Trichloro-acetic acid

chloride

100%



� Alcohols, Glycols, Phenols Conc. 25° 50° 75° 100° 125° 150°

� Pentanol (amyl alc.) 100% � Benzyl alc. 100% � n-Butyl alc. 100% � sec. Butyl alc. 100% � tert. Butyl alc. 100% � Butyl phenol (1-butyl-2-

hydroxy benzene)

100%

� Cresole 100% � Cyclohexanol 100% � 4-Hydroxy-4-methyl-2-

pentanone 100%

� Ethanol 100% � Ethylene glycol 100% � Glucose 100% � Glycerol 100% � Methanol 100% � Phenol 100% � Phenol 10% � Propanol 100% � Pyrogallol (1,2,3-trihydroxy

benzene)

100%

� Aldehydes, Ketones Conc. 25° 50° 75° 100° 125° 150°

� Acetone 100% ✕ � Acetone 50% � Acetone 10% � Acetone 5% � Acetophenone 100% ✕ � Acetyl-acetone 100% ✕ � Acroleine 100% ✕ � Benzaldehyde 100% ✕ � Butanone 100% ✕ � Chloral 100% � Crotonaldehyde 100% � Cyclohexanone 100% ✕ � Diisobutylketone 100% � Formaldehyde 30% � Furfural 100% � Methyl-isobutylketone 100% ✕ � Salicylic aldehyde 100%



� Amines *please refer also to chapter 6

Conc. 25° 50° 75° 100° 125° 150°

� Aniline 100% � n-Butyl amine 100% ✕ � sec. Butyl amine 100% � tert. Butyl amine 100% � Diethyl amine 100% � Diethylene triamine 100% � Dimethyl amine 100% ✕ � Dimethyl aniline 100% � Ethylene diamine 100% ✕ � Mono ethanol amine 100% ✕ � Morpholine 100% ✕ � Phenyl hydrazine 100% � Piperazine 100% � Pyridine 100% ✕ � Triethyl amine 100% � Nitriles, Nitro or sulfur

products Conc. 25° 50° 75° 100° 125° 150°

� Acetonitrile 100% � Acrylonitrile 100% � Carbon disulfide 100% � Nitro-benzene 100% � Nitro-methane 100% � Esters Conc. 25° 50° 75° 100° 125° 150° � Butyl acetate 100% � Butyl acrylate 100% � Cyclohexyl acetate 100% � Dimethyl phtalate 100% � Ethyl acetate 100% � Ethyl acrylate 100% � Pentyl acetate 100% � Tributyl phosphate 100% � Ether oxydes Conc. 25° 50° 75° 100° 125° 150° � Chloromethyl methylether 100% � Dioxane 100% ✕ � Diethyl ether 100% � Furane 100% ✕ � Ethylene oxyde 100% � Propylene oxyde 100% ✕ � Tetrahydrofurane (THF) 100%



� Chlorinated

hydrocarbons Conc. 25° 50° 75° 100° 125° 150°

� Allyl chloride 100% � Benzyl chloride 100% � 1-Chloro-pentane 100% � Chloro-benzene 100% � Chloroforme 100% � CFC 113 * 100% � CFC 114 * 100% � CFC 11 * 100% � CFC 12 * 100% � Dichloro-benzene 100% � Dichloro ethane 100% � Epichlorhydrine 100% ✕ � Ethyl chloride 100% � HCFC 22 100% � HFC 134 a 100% � HFC 407 c 100% � HFC 410 a 100% � Lauryl chloride 100% � Methyl chloride 100% � Methylene chloride 100% � Tetra-chloro ethylene 100% � Trichloro-benzene 100% � 1,1,1-trichloro ethane 100% � Trichloro ethylene 100%

� Other halogenated

hydrocarbons Conc. 25° 50° 75° 100° 125° 150°

� 1-Bromo-butane 100% � 1,2-Dibromo ethane 100% � Iodoforme 100% � Methyl bromide 100% The compounds marked by an asterix (*) are chloro-fluoro-carbons, which have been banned because of their

atmospheric ozone depletion effect. The information here is given only for general purposes.



� Hydrocarbons Conc. 25° 50° 75° 100° 125° 150° � Benzene 100% � Butadiene 100% � Butene 100% � Cyclohexane 100% � Dekaline 100% � Heptane 100% � Hexane 100% � Kerosene 100% � Methane 100% � Naphta 100% � Naphthalene 100% � Octane 100% � Octene 100% � Propane 100% � Styrene 100% � Terpentine 100% � Toluene 100% � Xylene 100% � Miscellaneous Conc. 25° 50° 75° 100° 125° 150°

� Crude Oil � Hydrogen peroxide 30% � Kerosene � Light Fuel � Milk � Mineral oil � Oil Gilotherme � Oil Voltalef 1 � Oil Voltalef 3 � Petrol E � Potable water � Pyralene oil � Seawater � Silicon oil S 510 � Toluene diisocyanate (TDI) � Urea 50%


Chapter 4

KYNAR®

Long term ageing and stress resistance behaviour

The trials for long term chemical resistance are inspired by the standard ISO 4433 and has been

adapted in the following way:

Test specimen according to the standard ASTM D 1708 were cut out of an extruded band of 0,7 mm

thickness. These specimen were then placed into a recipient in full immersion of the chemical either

without tension or in a folded manner according to the description of the standard ASTM D 1693.

The evolution of the weight and the tensile properties were then noted and a classification was noted

according to the principle of the standard ISO 4433 for test specimen without tension and for the

folded ones under tension.

3 categories are thus established:

+ non-limited use (small variations of weight and tensile properties)

0 limited use (use only in absence of pressure or stress)

- do not use

In case the specimen without tension leads to a positive result and the specimen under tension

obtains a negative result, the overall usability must be interpreted such that KYNAR® does not

sustain strong stress nor tension under the conditions of the chemical exposed.


4 - KYNAR® - Long term ageing and stress resistance behavior

Reactant Temp.

(°C) Exposure

time under

tension no

tension � Acids � Acetic acid 50 % 130 1 y + +

� Acetic anhydride conc. 23 1 y 0 0

� “Eau régale” HCl 35 % /HNO3 65% 2 / 1 90 1 y + +

� Etching solution H3PO4 (85 %) 85 %,

CH3CO2H 5 %, HNO3 (64 %) 5 %, H2O 5 %

90 4 m + +

� Hydrobromic acid 66 % (conc.) 90 1 year + +

� Hydrochloric acid 35 % (conc.) 130 1 y + +

� Hydrochloric acid + dichloroethane (10 %) 90 6 m + +

� Hydrochloric acid + dichloroethane (10 %) 130 6 m 0 +

� Hydrochloric acid + methanol (10 %) 50 6 m + +

� Hydrochloric acid + methanol + chloroforme 50 6 m + +

� Nitric acid 32% 90 1 y + +

� Nitric acid 32 % 130 6 months + +

� Nitric acid 52 % 130 2 m 0 0

� Nitric acid 65 90 6 m + +

� Nitric acid 98 % (conc) 50 2 m + +

� Nitric acid 98 % 90 2 m - -

� Oxalic acid 250 gl-1 75 2 m + +

� Phosphoric acid 85 % (conc.) 130 1 y + +

� Sulfuric acid 50 % * 130 1 y + +

� Sulfuric acid 80 % * 130 6 m - -

� Sulfuric acid 80 % * 90 1 y + +

� Sulfuric acid 96 % * 50 6 m 0 +

� Sulfuric acid 96 % * 75 3 m - +

� Sulfuric acid 99,2 % * 50 6 m - +

� Sulfuric acid 99,2 % * 23 6 m 0 +

� Sulfuric acid saturated with chloride 65 - 98 % 23 8 m + +

� Sulfuric acid 98 % + chloroforme (10 %) 50 6 m + +

� Sulfuric acid 98 % + diethylether (10 %) 50 6 m + +

� Sulfochromic acid CrO3 50 %, H2SO4 15 % 90 1 y + +

� Trichloroacetic acid 50 % 75 4 m + +

* please also refer to chapter 9


4 - KYNAR® - Long term ageing and stress resistance behavior

Reactant Temp.

(°C) Exposure

time under

tension no

tension

� Bases *please refer also to chapter 6 � Ammonium hydroxide solution 20 % 23 6 m + +

� Ammonium hydroxide solution 20 % 50 3 m + +

� Ammonium hydroxide solution 20 % 90 1 m - +

� Ammonium hydroxide solution 29 % 23 9 m + +

� Ammonium hydroxide solution 29 % 50 9 m - +

� Ammonium hydroxide solution 29 % 75 2 m - -

� Sodium hydroxide 10 % 23 2 months - +

� Sodium hydroxide 10 % 50 2 m - +

� Sodium hydroxide 10 % 90 2 m - +

� Sodium hydroxide 45 % 90 1 year - +

� Sodium hydroxide 45 % 130 3 m - -

� Sodium hydroxide 10 % +1,7% Triton X100 23 1 m - +

� Sodium hydroxide 10 % +20% methanol 50 1 m - +

� Sodium carbonate solution 40 % 90 6 m + +

� Tetramethyl ammonium hydroxide (TMAH) 23 4 m + +

� Tetramethyl ammonium hydroxide 50 2 m - +

� Halogens and inorganic halogenated

derivatives

� Bromine 60 1 y + +

� Chlorine gaseous without light 100 11 d + +

� Chlorine gaseous with UV light exposure 30 11 d - +

� Hypochlorite solution 48° « javeline » 90 3 months - +

� Hypochlorite solution 48° « javeline » 130 3 m - 0

� Hypochlorite solution 100° « javeline » 90 15 days - +

� Phosphoroxy trichloride (POCl3) 50 4 m 0 0

� Phosphor trichloride (PCl3) 98 % 50 1 y + +

� Sodium chlorite (NaOCl) 845 gl-1 60 6 m - +

� Sodium chlorate (NaClO4) 500 gl-1 90 1 year + +

� Sulfuryl chloride (SO2Cl2) 23 4 m + +

� Thionyl chloride (SOCl2) 50 4 m + +

� Surfactants � anionic surfactants 90 2 months + +

� anionic surfactants 130 2 m + 0

� non-ionic surfactants 90 2 m + +

� dish washing detergent 90 6 weeks + +


4 - KYNAR® - Long term ageing and stress resistance behavior Reactant Temp. (°C) Exposure

time under

tension no

tension � Hydrocarbon solvents � Crude oil 90 2 years + +

� Crude oil 130 2 y + +

� Crude oil 150 2 y + +

� Cyclohexane 90 4 m + +

� Decaline 90 4 m + +

� Tetraline 90 4 m + +

� Toluene 90 9 months + +

� Xylene 90 2 y + +

� Halogenated solvents � Benzene / chlorobenzene (1 / 1) 130 6 months 0 0

� Chloro-acetyl chloride 90 4 m 0 0

� Chlorobenzene

� Chloroforme 23 4 m + +

� Chloroforme 50 4 m + +

� 1,2-Dichloroethane 90 1 y + +

� Dichloromethane 50 4 m + +

� Dichloromethane 90 4 m + +

� Perchloroethylene 90 9 m + +

� Tetrachlorocarbon 90 6 m 0 0

� Trichloroethylene 90 1 year + +

� 1,1,1-Trichloroethane 90 4 m + +

� Oxygenated solvents � t-Butyl methyl ether 50 4 m + +

� Cyclohexanone 23 4 m 0 0

� Cyclohexanone 50 2 weeks - -

� Dibutyl phthalate 90 4 m + +

� Ethyl acetate 50 6 m - -

� Ethyl 2-ethoxy-acetate 50 4 m + +

� Ethylene glycol 130 1 year + +

� Glycerol 130 1 y + +

� Isopropanol 130 4 months + +

� Isopropanol 60 % +H3PO4 23 %+P2O5 17 % 130 4 m + +

� Methanol 90 4 m + +

� Phenol 10 % 90 1 y + +

� Ultra pure water (resistance 18 MO) 150 1 y + +


5 - Solvents for KYNAR® PVDF

� Active solvents

(Dissolve at least 5 - 10 % KYNAR® resin at room temperature.)

Boiling point (°C) Flash point (°C)

� Acetone 56 - 18

� Tetrahydrofuran (THF) 65 -17

� Methyl ethyl ketone (Butanone) 80 - 6

� Dimethyl formamide (DMF) 153 67

� Dimethyl acetamide (DMA) 166 70

� Tetramethyl urea 177 75

� Dimethyl sulfoxide (DMSO) 189 35

� Trimethyl phosphate 195

� N-methyl-2-pyrrolidone (NMP) 202 95

� Intermediate solvents

(Do not swell or dissolve KYNAR® resin at room temperature, but at elevated temperature

and keep the resin in solution when cooled to ambient temperature.)


� Butyrolactone 204 98

� Isophorone 215 96

� Carbitol acetate 217 110

� Latent solvents

(Do not dissolve or substantially swell KYNAR® resin at room temperature, but at elevated

temperature.

When cooled to room temperature the resin crystallizes / precipitates from the solution.)


� Methyl isobutyl ketone 118 23

� N-butyl acetate 135 24

� Cyclohexanone 157 54

� Diacetone alcohol 167 61

� Diisobutyl ketone 169 49

� Ethyl acetoacetate 180 84

� Triethyl phosphate 215 116

� Propylene carbonate 242 132

� Dimethyl phthalate 280 149

� Glycol ethers ≥ 118 ≥ 40 � Glycol ether esters ≥ 120 ≥ 30


6 - Resistance of KYNAR® PVDF to BASES and ALKALIS

KYNAR®

PVDF resists well to a large variety of different chemicals. However, it has been well

established that bases and alkalis can chemically attack PVDF resins leading to chemical

embrittlement (for a litterature review please refer to the end of this chapter). The extent of the

chemical attack of PVDF by different bases is greatly governed by temperature, concentration and,

in particuliar, by the type of base.

The general mechanism of base attack on PVDF relies on the dehydroflourination reaction which is

initiated by absorbed base molecules. The resultant double bonds formed by the elimination of HF

from the polymer backbone give rise to coloration. In case the dehydrofluorination reaction is very

pronounced the material becomes brittle.

� Molecular mechanism of the base attack:

Since the absorption of a base is the prerequisite for the chemical attack, the solubility of the base in

PVDF becomes a most dominant factor. The other important factor is the reactivity of the base.

For a given base these factors depend on temperature and concentration.

The solubility of sodium hydroxide in PVDF is very low. At higher temperatures this leads to a

distinct surface degradation with the formation of a black brittle degraded skin with underlying non-

degraded PVDF which is impermeable and protects underlying material as long as it is undamaged.

Under stress the cracks formed in the brittle skin can propagate into the bulk material leading to

failure.

For most applications in the chemical process industry we recommend to follow the indications

given in the table for KYNAR® homopolymer:

� Sodium hydroxide aqueous solution

25° 50° 75° 100° 125° Comments

� 4 gl-1 pH = 13 yellow

� 40 gl-1 pH = 14 brownish

� 100 gl-1 10 % X black

� 450 gl-1 45% X black

CCC

CC

C

H H HH H

F F F FF

CCC

CCC

H HH HH H

F F F F F F

B

B+

H F- +


The importance of the solubility in PVDF and the reactivity of the base in the chemical degradation

of PVDF are illustrated in the following table comparing the chemical compatibility of different

amines in a series of increasing molecular size :

� Amines Formula 25° 50° 75° 100° 125° 150°

� Dimethyl amine (CH3)NH ✕ � Ethanol amine HOC2H4NH2 ✕ � Morpholine (OC4H8NH) ✕ � Pyridine (C5H5N) ✕ � n-Butyl amine C4H9NH2 ✕ � Diethyl amine (C2H5)2NH � Dibutyl amine (C4H9)2NH � Tributyl amine (C4H9)3N � Fatty amine C16H33NH2

� KYNAR FLEX® PVDF copolymers offer improved base resistance

KYNAR FLEX® , PVDF copolymers, offer a significantly improved chemical resistance due to two

effects.

- The higher flexibility reduces stress cracking significantly.

- The perfluorinated comonomer disrupts the dehydrofluorination process suppressing the

embrittlement.

� Dehydrofluorination and the blocking of its progress in KYNAR FLEX® PVDF copolymers

The partial blocking of the dehydrofluorination reaction results in significantly improved colour

retention and reduction of material embrittlement.

CC

CCCC

H HH HH H

F F F F F F

CCCCC

C

H H HH H

F F F FF

HF HF

CCCCC

C

H H H H

F FF F

CC

CCCC

H F CH H

F F F FF

FFF

HFHF

CCCCC

C

H F C H H

F F F FF

FF F

CC

CCCC

H H F CH H

F F F F F F

FFF

PVDF

KYNAR FLEX


Laboratory test results :

� Sodium Hydroxide (NaOH) 90°C 3 months

KYNAR®

homopolymer 1000 HD and 740

KYNAR FLEX®

3120-50

KYNAR FLEX®

2850

KYNAR FLEX ® 2800

pH 13 0/- + + + pH 14 - +/0 +/0 + 10 % - +/0 +/0 + 20 % - 0/- 0 +

Based on our laboratory tests and experience in applications using KYNAR FLEX® grade 2850 we

recommend the following temperature concentration limits for practical use in chemical process

units :

� Sodium hydroxide aqueous solution

20° 40° 60° 90° 125° Comments

� 4 gl-1 pH = 13

� 40 gl-1 pH = 14

� 100 gl-1 10 %

� 200 gl-1 45%

Litterature on PVDF resistance to bases :

« Cracking of Poly(Vinylidene Fluoride) linings in chemical tankers » P.ACID Lepoutre, C.D.

Sterling, V.S.M. Van Tilburg, Corrosion Australia 15(6), 9 (1991)

« Stress corrosion cracking of Poly(Vinylidene Fluoride) in sodium hydroxide » S.V. Hoa, P.

Oulette, Pol. Eng. And Sci. 23(4) , 202 (1983)

« Cracking of Poly(Vinylidene Fluoride) due to chemical attack » , C.D. Sterling, V.S.M. Van

Tilburg, N.ACID Miller, Polymers + Polymer Composites, 1(3), 167 (1993)

« Phase transfer catalysis in Dehydrofluorination of Poly(Vinylidene Fluoride) by aqueous sodium

hydroxide solutions » H. Kise, H. Ogata, J. Pol. Sci. 21, 3443 (1983)

« Verhalten von Polyvinylidenfluorid (PVDF) gegen Natronlauge » E. Barth, Kunststoffe 72, 5

(1982)

« The stability of fluorine-containing polymers to amines » M.I. Bro J. Appl. Pol. Sci. 1(3), 310

(1959)


7 - Resistance of KYNAR® PVDF to CHLORINE

KYNAR®

PVDF resists well to molecular chlorine.

However, chlorine radicals, which are formed under UV-radiation, higher temperatures or other

radical sources, attack PVDF.

Thus, to effectively protect the installation for use in chlorine service an appropriate UV-shielding

must be provided by either pigmentation of the resin or an UV-filter varnish on the outside.

� Molecular mechanism of the chlorine attack:

+UV

CC

H

F F

H

Cl Cl Cl* Cl*

CC

F F

HCl

CC

F F

HCl CC

F F

Cl Cl

Cl*

Cl*

� The chlorination can be analyzed by the following methods:

� increase in weight

� measurement of the melting point: chlorination results in a drop in melting point

� NMR spectroscopy: i.e. by NMR of the F19 isotope it is possible to establish the degree of

chlorination

� mechanical measurements, i.e. tensile testing, chlorination results in a drop in mechanical

strength

� melt viscosity


7 - Resistance of KYNAR® PVDF to CHLORINE

The following examples give an idea of the scope of the analysis methods cited and of the

performances of PVDF :

� Tube at the exit of a chlorine electrolysis cellule 7 years in service • Melting point

new PVDF exterior of tube inside of tube particularly degraded

part inside

Tm = 170°C Tm = 170°C Tm = 162°C Tm = 158°C

• Tensile properties

new PVDF tube 54 MPa at yield

tube in service 45,7 MPa at yield

• F19 NMR spectroscopy

Definition of a chlorination coefficient: Ka b

a= − ×100

where: a = integration of all fluorine signals, b = all fluorine signals due to VF2

The measurement was done at 2 sites of the tube - near the cellule and further away:

K-values : near the cellule far away from cellule

inner surface of tube 17,0 12,8

middle of tube wall 1,2 1,0

outer surface of tube 0 0

� Chlorine collector - humid chlorine gas 80°C 10 years in service • Melting point

new PVDF external surface inner surface

Tm = 170°C Tm = 164°C Tm = 152°C


external surface inner surface

K value 14,0 33,9

� Black pigmented tube - chlorine gas 70°C 7 years in service • Melting point

new PVDF external surface inner surface

Tm = 170°C Tm = 170°C Tm = 170°C


external surface inner surface

K value 0 < 1


new PVDF tube tube in service

tensile stress at yield (MPa) 54 54


8 - Resistance of KYNAR® PVDF to SULFURIC ACID

KYNAR®

PVDF resists well to diluted sulfuric acid up to concentrated sulfur. However, KYNAR®

PVDF can be attacked when the concentration of the sulfuric acid passes from concentrated to

« fuming » sulfuric acid (96 to 98%).

The reason for this behaviour is that sulfur trioxide (creating the fumes) can by absorbed by PVDF.

This compound can react with PVDF leading to dehydrofluorination similar to bases. Therefore

coloration occurs and when the degradation is advanced a black brittle surface layer forms.

Therefore the chemical resistance of KYNAR® PVDF follows a clear concentration/temperature

pattern which is clearly related to the appearance of sulfur trioxide.

Chemical resistance of KYNAR® PVDF as a function of temperature and concentration

Example of an application :

� Pipe at the exit of an acid distillation tower 10 years in service

• Characteristics : pipe made by thermoforming and welding of sheet with 15 mm

thickness

• Operation conditions

110 – 120°C at vacuum of 70 mbar

vapours of aqueous sulfuric and nitric acids

Yearly inspections have never revealed any problem, nor was there any maintenance

operation necessary.

0

20

40

60

80

100

120

140

0 10 20 30 40 50 60 70 80 90 100

Concentration (%)

Tem

pera

ture

(°C

)

98%

does not resist

resists


Table of experiments performed : KYNAR® in Sulfuric acid

Conc.

%

Exp. time 23°C wt

nt 50°C wt

nt 75°C wt

nt 90°C wt

nt 130°C wt

nt

50 � 1 y + +

80

� 3 m

� 6m

� 1 y

+

+

+

- +

-

94

� 2 m

� 3 m

� 6 m

+

0

0

+

+

+

-

+

+

+

+

+

96

� 1 w

� 2 m

� 3 m

� 6m

� 1 y

+

+

0

0

+

+

-

+

+

0

+

0

98

� 1 w

� 7w

� 2 m

� 3 m

� 6 m

+

+

0

0

+

+

-

0

0

-

+

-

99,2

� 1 w

� 7w

� 3 m

� 6m

� 1 y

0

-

+

+

-

-

+

+

-

0

-

-

0

_

« wt » : test specimen under tension « nt » : test specimen without tension


9 - Resistance of KYNAR® PVDF to BROMINE

KYNAR®

PVDF resists very well to bromine - even at higher temperatures. During the service time

bromine diffuses into the PVDF layer, an effect which is readily visible by eye due to the red-orange

coloring of the PVDF. However, this effect is perfectly reversible. After desorption of the bromine

KYNAR® PVDF regains its original color.

Permeability of bromine in KYNAR PVDF as a function of temperature

0

5

10

15

20

25

30

35

40

0 10 20 30 40 50 60

Temp (°C)

Per

mea

bilit

y

permeability units: g / (m

2 day) thickness 50 µm

Examples of installed pieces in bromine service � DN 40 tube ambient temperature 8 years in service

• Thermal treatment of tube Loss of 1,4 % weight, essentially bromine.

Restitution of original color

• Melting point new PVDF : Tm = 170°C

Tube : Tm = 170°C

• NMR and IR spectroscopy No bromine bound to PVDF



tensile stress at yield (MPa) 52 50.8

elongation at break (%) 200 197


9 - Resistance of KYNAR® PVDF to BROMINE

Examples of installed pieces in bromine service � Gas tube temperature 70 - 80°C 9 years in service

• Thermal treatment of tube

Loss of 1,5 % weight, essentially bromine.

Restitution of original color

• Melting point

new PVDF tube

Tm = 170°C Tm = 170°C

• NMR and IR spectroscopy

No bromine bound to PVDF



tensile stress at yield (MPa) 53 53

elongation at break (%) 100 96

� Isocontainer for bromine transport by rail

Ambient temperature, welded KYNAR®

sheets glued into steel container, service since 9

years

No problem detected since beginning of service.


10 - Chemical resistance of KYNAR FLEX® PVDF copolymers

Due to the more recent apparition of the KYNAR FLEX®

PVDF copolymers and their more

restricted use in the chemical process industry no extensive testing of chemical compatibility

exists.

Nevertheless, the available data and a sound reasoning of the influence of the nature of the PVDF

copolymers in comparison to the PVDF homopolymers allows to dress general guidelines which

will be discussed here.

The comonomer used to synthesize the KYNAR FLEX® grades is hexafluoro-propene (HFP)

which is a completely fluorinated molecule. Thus, the major factor responsible for the outstanding

chemical resistance of KYNAR® PVDF is not changed by the incorporation of a comonomer.

The main change induced by the incorporation of the HFP comonomer is a reduction in

cristallinity of the originally highly crystalline PVDF material. The reduced cristallinity directly

results in a decrease of the moduli and hence in a reduced mechanical strength at higher

temperatures. Also the reduced cristallinity results in an enhancement of permeation rates which in

turn leads to a further decrease in mechanical strength at higher temperatures.

As a conclusion we can state that the chemical resistance to organic compounds such as

hydrocarbons, halogenated organics and oxygenated organic compounds is reduced in its

maximum temperature limit in comparison to PVDF homopolymers.

We have defined a temperature increment « ∆ T » which should be subtracted from the maximum use temperature given for the PVDF homopolymer.

A comparative overview is given in the table below:

Property KYNAR®

homopolymer 1000 HD and 740

KYNAR FLEX®

3120-50 KYNAR FLEX®

2850

KYNAR FLEX®

2800

Melting Temperature (°C) 170 163 - 166 155 - 160 141 - 145 FLEX ural Modulus (MPa) 1800 659 1100 700 Vicat Softening Point (B50) ISO 306 (°C)

140 70 90 70

Heat Deflection Temperature ISO 75 (°C)

118 40 - 50 55 40 - 50

Tensile stress at yield (MPa)

49 - 52 27 - 29 32 - 39 23 - 27

Elongation at yield (%) 10 12 10 - 12 10 - 12 ∆ ∆ ∆ ∆ T (°C) 15 20 35

There is an important exception to the logic defined above. In the case where the attack of PVDF

by the chemical occurs on the surface and/or by stress cracking the resistance of KYNAR FLEX®

can be considerably higher than the PVDF homopolymer. The main reason for this advantage is

the reduced amount of stress build-up due to the lower modulus of the copolymers.



The following list gives an idea of the comparative chemical resistance in conditions where the

performance of the PVDF homopolymer is reduced due to stress cracking.

� Chlorine gas without UV 80°C 15 days

KYNAR®

homopolymer

KYNAR FLEX®

3120-50

KYNAR FLEX®

2850

KYNAR FLEX®

2800

resistance - + + +

� Chlorine gas under UV 80°C 15 days

KYNAR®

homopolymer

KYNAR FLEX®

3120-50

KYNAR FLEX®

2850

KYNAR FLEX ® 2800

resistance -- 0 0 0

With applied stress no material resists, but on unbent samples the following order in

resistance has been established:

KYNAR FLEX® 2800 = KYNAR FLEX

® 3120-50 > KYNAR FLEX

® 2850 >> KYNAR

® 1000 HD

� Sulfuric acid (H2SO4) 99.2% 50°C 3 months

KYNAR®

homopolymer

KYNAR FLEX®

3120-50

KYNAR FLEX®

2850

KYNAR FLEX ® 2800

resistance - + + +

� Hydrogen peroxide (H202) 70% 50°C 3 months

KYNAR®

homopolymer

KYNAR FLEX®

3120-50

KYNAR FLEX®

2850

KYNAR FLEX ® 2800

resistance - 0 +

� Sodium Hydroxide 20 % and Sodium hypochlorite “50°” – active chlorine 15,7% 4 months

KYNAR®

homopolymer

KYNAR FLEX®

3120-50

KYNAR FLEX®

2850

KYNAR FLEX ® 2800

resistance - + +/0 +



The following list gives an idea of the comparative chemical resistance in conditions where the

performance of the PVDF homopolymer is reduced due to stress cracking.

� Sodium Hypochlorite - “107°” or “active chlorine 33,9% - pH = 13 23°C 4 months

KYNAR®

homopolymer

KYNAR FLEX®

3120-50

KYNAR FLEX®

2850

KYNAR FLEX ® 2800

resistance 0 + + +

� Sodium Hypochlorite – “56°” or active chlorine 17,8% - pH = 12,5 23°C 6 months

KYNAR®

homopolymer

KYNAR FLEX®

3120-50

KYNAR FLEX®

2850

KYNAR FLEX ® 2800

resistance +/0 + + +

� Sodium Chlorate (600g/l) 78°C 5 months

KYNAR®

homopolymer

KYNAR FLEX®

3120-50

KYNAR FLEX®

2850

KYNAR FLEX ® 2800

resistance 0 +/0 +/0 +

� Sodium Hydroxide (NaOH) 90°C 3 months

KYNAR®

homopolymer

KYNAR FLEX®

3120-50

KYNAR FLEX®

2850

KYNAR FLEX ® 2800

pH 13 0/- + + + pH 14 - +/0 +/0 + 10 % - +/0 +/0 + 20 % - 0/- 0 +

Comments: In alkaline solutions the surface will often be colored after a short period of time depending on

concentration and temperature.

This coloration is due to a limited surface attack. It is less strongly pronounced with the FLEX grades.


11 - Permeability properties of KYNAR® PVDF

The permeability of gases and liquids is an important design factor for thermoplastics in chemical process

applications. KYNAR® PVDF has outstanding barrier properties to a large variety of chemicals.

In the case of permeation of a gas permeability is proportional to the gas pressure and inverse proportional

to the polymer layer thickness :

Gas permeation :

tpA

LmP

⋅∆⋅⋅=

In the case of liquids no pressure dependence exists, but there might be a dependence of concentration in

the case of mixtures or solutions. In many cases the pure liquid permeability gives a good indication.

Luid permeation :

tA

LmP

⋅⋅=

P : permeation m : amount of permeant L : layer thickness

A : exposed surface for permeation t : time

Permeation through thermoplastics is temperature dependent and can be approximated by an Arrhenius

equation.

( ) ( ) ( )

−⋅−

⋅=01

10 expττ

ττR

EPP A

P(τ0) : permeability at temperature 0 P(τ1) : permeability at temperature 1 EA : activation energy R : universal gas constant

Ideally, permeation is inverse proportional to the sheet thickness. In some cases different types of

cristallinity or surface quality can change the permeability value to a slight extent. These parameters may

depend on the manufacturing of the sheet, pipe or film.

Some solvents which have a strong swelling effect will also effect the layer thickness dependence of the

permeation.


11 - Permeability properties of KYNAR

® PVDF

Water permeation – KYNAR® 1000HD PVDF homopolymer

The symbols correspond to measured points. Thin samples are extruded films. Thicker samples are

measured on extruded pipes.

0,01

0,1

1

10

100

1000

0,01 0,1 1 10

Thickness (mm)

Per

mea

bilit

y (g

/(da

y.m

^2)

50°C20°C80°C



® PVDF

Water permeation – different KYNAR® grades and temperature dependence

0,100

1,000

10,000

100,000

1 / temperature (K)

Per

mea

bilit

y (g

.mm

/(da

y.m

^2)

KYNAR 740

KYNAR 720

KYNAR 460

KYNAR FLEX 2850

KYNAR FLEX 2800

Série6

KYNAR 720

KYNAR 740

KYNAR 460

KYNAR FLEX 2850

KYNAR FLEX 2800

100°C 80°C 60°C 40°C 20°C



® PVDF

Permeation data of KYNAR® PVDF homopolymer grades for gases

Measurements according to ASTM D 1434 on extruded films

0,1

1

10

100

1000

10000

0,0024 0,0026 0,0028 0,003 0,0032 0,0034 0,0036

1 / temperature (K)

perm

eabi

lity

(cm

^3.m

m/m

^2.d

ay.b

ar)

O2

N2

He

CO2

Cl2

H2S

SO2

HCl

NH3

NO2

CH4

140°C 120°C 100°C 80°C 60°C 40°C 20°C



® PVDF

Permeation data of KYNAR® PVDF homopolymer grades for organic solvents

Measurements by weight loss method on extruded films of approx 1 mm thickness

0,01

0,1

1

10

100

Temp (°C)

perm

eabi

lity

(g.

mm

/ m

^2.d

ay)

methanol

toluene

chloroforme

2030405060708090100

ethanol

perchlorethylene

dichloroethane

hexane



® PVDF

Tables with data on swelling and weight gain of KYNAR® PVDF homopolymer and KYNAR

FLEX® copolymer grades

Measurements on immersed samples of extruded sheet.

Weight gain expressed in percent.

23°C 75°C 90°C Kynar®

740 Kynar®

Flex 2850 Kynar®

Flex 2800 Kynar® Flex 2850

Kynar® 740

HCl 37% 0 0 0 0,14 H2SO4 96% 0,01 0,02 0,02 0,19 HF 100% 0,3 0,32 0,28 0 Cl2 gas (4 bar) 0,32 water 0,01 0,01 0,01

toluene 0,2 1,8 2,4 4,1 cyclohexane 0 0,03 0,04 0,54 2-butanone 9,2 14 X MTBE 0,65 0,9 6,3 methanol 0,03 0,06 0,08 2,9

X signifies dissolution


12 - Comparison of chemical resistance of KYNAR

® PVDF

with others thermoplastic materials used in the chemical process industry

012345

halogenated solvents

esters, ketones

aromatic solvents

aliphatic solvents

weak basesstrong bases

strong acids

halogens

strong oxidants

PVDFPVCHDPEPPPES-GF

5 : excellent resistance 4 : fair resistance 3 : limited resistance 2 : low resistance

1 : no resistance comparison for 90°C

� Comparative pressure resistance based on long term creep (25 years)

Wall thicknesses are not the same for a standard 10 bar nominal pressure piping system.

As an example for a 63-mm diameter pipe wall thickness would be:

PVC-U 3,0 mm PP 5,8 mm PVDF 2,5 mm.

0

2

4

6

8

10

12

20 40 60 80 100 120 140

Temperature (°C)

Nom

inal

Pre

ssur

e (b

ar)

PVC-UPPPVDF


KYNAR


� For questions regarding availability and prices please contact :

ARKEMA S.A. Technical Polymers Division

420, rue d’Estienne d’Orves - 92705 Colombes (France) Tel. (33) 01 49 00 80 80 - Téléfax (33) 01 49 00 83 96

� Adresses of regional sales offices:

ARKEMA NORDEN ARKEMA UK Ltd. ARKEMA NORDEN (Danmark) Colthrop Way - Thatcham (Suede)

Herlev Hovegarde 195 Newbury - Berkshire Sveagarten 65 B

2730 Herlev RG 13 4 LW 57339 Tranas Tel : 44 503 939 Tel : (01635) 87 0000 Tel : 14014755 Fax : 44 503 940 Fax : (01635) 86 1212 Fax : 14019950

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1066 XT Amsterdam Yildiz Cad. Kessaf Sok n° 4

Tel : (20) 614 25 11 Besiktas 80700

Fax : (20) 669 2231 Istanbul Tel : (212) 227 6384 Fax : (212) 227 6386

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40474 Düsseldorf 1180 Bruxelles Tel : (0211) 4552 00 Tel : (2) 370 20 32 Fax : (0211) 4552 112 Fax : (2) 332 12 84

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Karlsplatz 1 / Steige 1 / Büro n°8 8143 Stallikon

A 1010 Wien Tel : (1) 701 8121

Tel : (1) 503 5055 Fax : (1) 700 3921 Fax : (1) 503 505520

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Degli Artigianelli 10 Rua Artilharia UM 63 Poligon Industrial Pratenc

20159 Milano 4’ Dto Lisboa Calle 100s/n Acesso A

Tel : (02) 668 111 Tel : 113 806 004 08820 - El Prat De Llobregat

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Technical Polymers Division 420, rue d’Estienne d’Orves - 92705 Colombes (France)

Tel. (33) 01 49 00 80 80 - Téléfax (33) 01 49 00 83 96

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