Guidelines for chemical resistance of polymers

Transcription

1 The extent t which plymers are subjected t attack by chemicals is determined by a number f parameters, related bth t the chemical and the plymer invlved: Plymers are mre susceptible t slvent r chemical attack when under stress and/r strain. Stress can be internal, caused during the manufacturing f the prduct, r due t externally applied lads. The nature and strength f the chemical will affect the amunt f damage. While sme dilute chemicals will nt attack a plymer, mre cncentrated slutins can d cnsiderable harm. The extent f chemical attack n a certain plymer is mainly dependent n the chemical structure f the plymer. In additin, the severity f attack generally reduces with increase in plymer mlecular weight, crystallinity, and level f chain branching. The effects f chemical expsure are increased at higher temperatures and with lnger perids f expsure. Chemical attack can cause plymers t partially disslve, plasticize, react chemically and absrb these chemicals. These events will nt always lead t prduct failure, but the mechanical prperties may be reduced and the weight f the prducts may change. Fr nn-laded parts this will ften nt influence the parts functinality. Mst imprtant, hwever, is that chemical attack can cause stress cracks, which can be defined as fine cracks n r under the surface f the plastic. These cracks may range frm thse f relatively large size, individually visible t the unaided eye, dwn t thse f almst micrscpic size, visible nly by the appearance f blming r haziness (a dull surface). Stress cracks r crazes will usually lead t failure r rejectin f the affected part. Attack will usually lead t preferential sftening/plasticizing f the plymer which in turn will lwer the stress level fr crack generatin. The amunt and severity f cracking/crazing depends largely n the chemical similarity f the slute and the slvent. These data are based upn infrmatin frm material suppliers and careful examinatin f available published infrmatin and are believed t be accurate. Hwever, since the resistance f plastics can be affected by the mentined factrs, this infrmatin shuld be cnsidered as a general guide rather than an unqualified guarantee. Ultimately, the custmer must determine by himself the suitability f the material used in varius slutins. = Negligible effect: gd resistance, n reductin in physical prperties, shuld be suitable fr applicatins where these envirnmental cnditins exists.

2 ISOCLEAR DAFNELOY PC ISOFIL ISOPLEN ISOGLASS DAFNELEN PP ISONYL DAFNEMID PA 6 ISOBLEND DAFNEBLEND PC-ABS ISODUR DAFNELOY PBT ISORYL PPO ISOTER DAFNELAC ABS ISOFORM DAFNELAN POM Guidelines fr chemical resistance f plymers 0 = Limited absrptin r attack: Shuld be suitable fr mst applicatins. Little reductin in physical prperties. Sme higher reductin in physical prperties ccurs after lng expsure r at high temperature. The user is advised t make its wn test t determine the suitability f the material in the particular envirnment. - = Extensive attack: The material is damaged r significant changes in physical prperties ccur after expsure t the substance. The prduct is nt recmmended. = resistant = limited resistance - = nn-resistant Substance Cnc. T ( C) T ( C) T ( C) T ( C) T ( C) T ( C) T ( C) T ( C) Acetamide 50% Acetic Acid 10% Acetic Acid 50% - - Acetne Acrylic Acid 10% Acrylic Acid 50%

3 Ammnia 10% Ammnia 50% Ammnium 10% Ammnium 50% Aniline - - Aqua Regia 10% - - Aqua Regia 50% Bric Acid % Benzene Benzine Brake Fluids - - Brmine 10% Butyl Alchl - - Calcium Chlride - Carbn Disulphide % Carbn Tetrachlride (wet) Chlrine (wet) - - Chlrbenzene % - - Chlrfrm - Chrmic Acid 10% - - Chrmic Acid 50% Citric Acid 10% Citric Acid 50% Cpper Sulfate 10% - Cyclhexane - -

4 Cyclhexanl - - Cyclhexanne Cyclhexene Cresl - - Decalin Diesel Fuel - Dixane Distilled Water Ethyl Acetate - - Ethyl Alchl 85% (Ethanl) Ethylene Glycl - Ethylene Oxide - Fd Oil Flurine - Frmaldehyde 37% Frmamide Frmic Acid 10% Frmic Acid 50% - - Frst Prtectin Agent Gasline Glyclic Alchl (Glycerl) Heating Oil Heptane - - Hydrclric Acid 10% Hydrclric Acid 35% - - Hydrfluric Acid 10% -

5 Hydrfluric Acid 50% Hydrgen 30% - Perxide - Hydrgen Sulphide Idine (slutin) Isprpyl Alchl (Isprpanl) Kersene - - Lactic Acid 10% Lactic Acid 90% - Linseed Oil Mercurchrme - - Methane (gaseus) Methyl Alchl (Methanl) Methyl Ethyl Ketne - Methylene - - Chlride Milk Mineral Oil Nitric Acid 10% Nitric Acid 35% Nitrbenzene Nitrgen Oxalic Acid Oxygen (lw - - pressure) Ozne <5 ppm

6 Paraffin Oil % Perchlrethylene Petrleum, armatic free % - Petrleum Ether % - Phenl (cnc.) Phsphric Acid 50% Ptassium 10% - Ptassium - 50% - - Pyridine Sea Water - - Silicne Oil Skydrl Sdium (ht) Sdium Bicarbnate Sdium Chlride 10% - Sdium Hydrgen Sulphite Sdium 10% - - Sdium 50% Sdium - - Hypclrite - Sdium Nitrate Sulfur Sulfuric Acid 10% - - Sulfuric Acid 35% Tartaric Acid 10%

7 Tartaric Acid 50% THF - - Tluene Trichlrethylene % Vinegar 10% Xylene - -