Compatibility of refrigerants with plastics, elastomers and metals

Compatibility with plastics. Information on compatibility of refrigerants SUVA^® R11, R12, R22 and R502 with plastics is given in table down, however, for each separate case of using it is necessary to perform compatibility tests because plastics of the same type have different molecular mass, structure of polymers, different plasticizers, and temperature and other factors can decrease plastics resistance to the influence of refrigerants.

Compatibility of SUVA^®
Plastics and elastomers (trade mark)	R11	R123	R12	R134a	R401A R401B R401C	R22	R407C	R410A	R502	R402A R402B	R404A	R124
ALATHON	1	1	1	0	1	1	0	0	1	-	0	0
Polypropylene	2	1	1	0	1	1	1	1	1	1	0	1
Polysterene (Sryrol)	2	2	1	1	2	2	1	1	2	2	1	1
Chlorinated PVH	1	1	0	0	1	1	0	0	1	1	0	0
PTFE (Teflon^®)	1	1	1	1	1	1	1	1	1	1	1	1
ETFE (Tefzel)	1	-	1	1	2	1	1	1	1	1	1	2
PVDF	0	-	0	1	1	1	1	1	1	1	0	0
Ionomer resin (Surlyn^®)	2	-	1	0	1	1	0	0	1	1	0	1
Intense resin (Lucite^®)	0	2	0	2	2	2	2	2	2	2	2	2
ABS (Kralfstic^®)	0	2	0	0	2	2	-	2	2	2	0	2
Cellulose material (Ethocel^®)	2	2	2	2	2	2	2	2	2	2	2	2
Epoxy resins	0	0	0	0	0	0	0	0	0	0	0	0
Polyacytamine (Delrin^®)	0	1	0	0	1	1	1	1	1	0	0	0
Polycarbonate (Tuffak^®)	0	2	0	0	2	2	-	1	2	2	0	0
Polybutyleneterephtalate (Crastin^®)	0	0	0	0	1	0	0	0	0	0	0	-
Polyarylate (Arylon^®)	0	-	0	0	2	2	1	1	2	2	0	-
Polyamide (Zytel^®)	0	0	0	0	0	0	0	0	0	0	0	0
Polyamide (Vespel^®)	-	-	0	-	0	-	0	0	0	0	0	0
PEB (Ultem^®)	0	-	0	0	1	1	-	-	1	-	0	0
Polysulfide	0	-	0	0	2	2	1	1	1	2	0	0

Designations: 0 - good compatibility, 1 - compatibility on the verge of permissible; 2 - non-compatibility

Compatibility with elastomers. As the laboratory research by "Du Pont" company has showed (see table up), elastomers, which successfully operated in combination with R12, have, as a rule, good compatibility with average pressure service blends (R401A, R401B and R401C) as well - see the table.

However, the degree of refrigerants effect on elastomers can change within a wide enough range depending on what plasticizers, fillers and other ingredients have been used in the compounding of the rubber compound; therefore, for each separate case it is necessary to have tests. Special attention should be paid to checking of compatibility of materials of circular section O-ring seals with refrigerants. Checking is usually performed in the laboratory conditions by sinking of elastomer samples into the liquid refrigerant at the room temperature and keeping it there till maximum swelling. Items with high degree of swelling are not recommended to use in the refrigeration systems charged with SUVA^® refrigerants.

Compatibility with metals. The majority of structural metals being used such as steel, cast iron, bronze, copper, tin, lead and aluminum, operate well with SUVA^® refrigerants under normal operation conditions, as the research made by "Du Pont" company has showed.

Under very high temperatures (for example, at blanching) some metals can act as catalytic agents accelerating fluorine contextures decay. Alloys of magnesium and aluminum containing more than 2 % of magnesium should not be used in the systems charged with SUVA^® refrigerants, especially if moisture can appear.

The majority of refrigerants of HCFC and HFC can react violently with highly active metals, for example, with alkali and alkali-land metals (natrium, potassium, barium, etc.), being in a free state. Metals become even more active in a fine-grained and powder kind. Aluminum and magnesium at that can react with fluorine-containing contextures, especially under high pressure. Such highly active materials cannot be placed in contacting with the refrigerants of HCFC and HFC groups before their reaction has been thoroughly investigated and taken proper safety measures.