Page 354 - BOLA Catalogue

Fluoroplastics - Heating
Due to the low heat transfer and the maximum surface temperature that may not be exceeded, it is very difficult to heat PTFE vessels. There are different methods to heat PTFE vessels:
» Heating by a heating mantle with surface sensor:
When heating with a heating mantle, a large surface of the vessel is covered. This supports the heat transmission and reduces the heating period. The mantle must have a sensor on its surface. This probe measures the temperature on the surface of the PTFE and switches the mantle of upon exceeding +250 °C. Only this way a deformation of the laboratory equipment caused by temporary overheating is avoided. In case of an intense increase of the temperature of > 380 °C hazardous decomposition products can occur.
We advise against the use of “usual” heating mantles and control systems. Their use may result in the same effects as the use of hot- plates (see below).
» Heating by a thermostat:
The heat transmission is provided by the bath medium (oils or other liquids). Controlled by an adjusted thermostat, the temperatures on the surface of the PTFE vessel will not become too high. Depending on the immersion depth, a big surface for a good heat transmission is provided. The handling of oils at high temperatures and the associated risk potential requires to work cautiously and safely, if necessary use protective clothing and equipment.
Not appropriate methods are:
» Flame (e.g. gas burner):
With this method, the surface temperature cannot be controlled. Due to temporary overheating decomposition products in the form of both invisible gases and white smoke occur. Those products are extremely hazardous to health.
» Hotplate:
Overheating can occur as well. Usual hotplates can only be switched
on or off. During the heating period, the plate is heated with full energy so that it almost glows. Afterwards, the hotplate is switched off and only heats for a few seconds. This so-called „pointing“ is enough to exceed the maximum temperature of +260 °C. It does not make sense to put the adjusting knob only to +150 °C. PTFE labware char on the underside and glue to the hotplate. The thermoplastics PFA and FEP melt directly, similar to a hot-melt-type adhesive. This can be preven- ted by putting an aluminium foil between hotplate and vessels but dangers for health cannot be avoided.
» For further information regarding “Safe handling of Fluoropolymers” we refer to the leaflet of Plastics Europe, which can be downloaded on the following sources:
Safety Advice
» PlasticsEurope AISBL; Avenue E. van Nieuwenhuyse 4/3; B-1160 Brussels/Belgium, Phone: +32 (0) 2 675 32 97, info@plasticseurope.org, www.plasticseurope.org
Main risks and adversarial effects
Fluoroplastics are inert plastics, at normal use there are no risks for human health and environment. If the material is exposed to temperatures of more than +350 °C, it is possible that hazardous materials such as HF, COF2 and others are released and can cause bad chemical burns which are not immediately noticeable.
Symptoms after contact
The materials released during thermal decomposition are very dan- gerous when getting in contact with eyes, skin or when being brea- thed in.
» Eyes: Redness, irritation, burning
» Skin: Redness, irritation, burning
» Breathing in: Headache, shortness of breath, illness, shivering,
fever (“polymerisation-fever”, raised pulse).
Special instructions for the case of breathing in:
The symptoms might only start some hours after breathing in. It is extremely important to seek medical advice to avoid lasting impacts!
First aid procedures
After breathing in, it is extremely important to seek medical advice. The person concerned should be immediately brought to a place with fresh air. It is also necessary to give him/her oxygen. In case of apnoea it is necessary to give artificial respiration, possibly by mouth-to-mouth resuscitation.
» In case of eye contact rinse immediately with water for at least 15 minutes.
» In case of skin contact wash immediately with water and soap (especially the skin under the nails).
» Additionally seek medical advice!
Dangers of fire
There are possible risks due to acid and toxic production which can occur during thermal decomposition (HF and COF2).
Precautionary measures in case of fire:
Take away the product from the fire but be careful. Stay against the wind direction and in sufficient distance. Appropriate extinguishing agents are water, CO2, foam, earth/sand. Wear special clothes such as respirator and skin protection against HF-vapours.
TECHNICAL INFORMATION
By the way: BOLA offers custom manufacture. From 1 piece. Hotline +49 (0) 93 46-92 86-0 353