0 معجب 0 شخص غير معجب
4 مشاهدات
سُئل مايو 24 في تصنيف تفسير الاحلام بواسطة nnectied (300 نقاط)

PTFE is ideally suited for the labware application because of its legendary resistance to just about anything including strong acids and bases. PTFE labware is also resistant to steam and has a temperature range of use covering the range of -200°C (-390°F) to +300°C (+570°F). Because of the three dimensional structure of PTFE at the molecular level, it is essentially intractable in any solvent, therefore explaining its unique resistance to dissolution in most solvents or strong acids and bases. The helical structure of the polymer chain, which is literally "sheathed" by the F atoms means that more chemically vulnerable carbon-carbon bonds of the chain are fully protected. Because of the very high purity of the PTFE starting material all products exhibit extremely low levels of extractables, even at elevated temperatures. The legendary non-stick properties of PTFE give it yet additional advantages for use in the laboratory.

PTFE magnetic stir bar is a device widely used in laboratories and consists of a rotating magnet or a stationary electromagnet that creates a rotating magnetic field. This device is used to make a stir bar, immerse in a liquid, quickly spin, or stirring or mixing a solution, for example.

Chemically resistant PTFE beaker is isostatically molded from virgin PTFE and machine finished to give a smooth surface for ease of cleaning and to eliminate contamination. PTFE beakers with pouring spouts are virtually immune to chemical attack, only attacked by some fluorine containing compounds at very high temperature and molten alkalis metals.

PTFE measuring cylinder is a substitute to glass measuring cylinder, it can be used to measure both acid liquids and alkaline liquids. PTFE has advantages of surface finish, low coefficient of friction, lubricity, high working temperature (up to 260º C), excellent dielectric properties, corrosion resistance.

PTFE crucible is made from chemically-inert ptfe, a synthetic polymer that can be heated to 270ºc without distortion. Crucibles display excellent chemical resistance and even heat transfer. The crucible is resistant to high temperatures and virtually all laboratory chemicals with machine-finished surface for easy cleaning.

PTFE tubes are most widely used as laboratory tube and for applications where chemical resistance and purity are essential. PTFE has a very low coefficient of friction and is one of the most “slippery” substances known.

PTFE digestion tank is a tank, whose size and appearance varies considerably depending on what it is used for. A household PTFE digestion tank for a single family can have a volume of less than one cubic meter, whereas an industrial-scale unit can easily surpass 5,000 cubic meters.

PTFE stirring rod is a piece of laboratory equipment used to mix chemicals. It's thicker and slightly longer than a drinking straw, with rounded ends. A stirring rod is used for mixing liquids, or solids and liquids. Stir rods are used as part of proper laboratory technique when decanting supernatants because the contact helps to negate the adhesion between the side of the glassware and the supernatant that is responsible for the liquid running down the side. The rods can also be used to induce crystallization in a recrystallization procedure, when they are used to scratch the inside surface of a test tube or beaker. They can also break up an emulsion during an extraction.

PTFE funnel is made of PTFE resin and sintered by cold pressing of dies. They have excellent corrosion resistance, good self-lubrication and non-adhesion. Therefore, the products are almost resistant to all chemical media, and have the characteristics of wear resistance, pressure resistance, low wiping coefficient and so on. The funnel is used to channel liquids or fine-grained substances into containers with a small opening. What's more, it can be used for pouring liquids or powder through a small opening and for holding the filter paper in filtration. In addition, it can be applied in transferring liquids in small containers.

PTFE tweezers make use of two third-class levers connected at one fixed end (the fulcrum point of each lever), with the pincers at the others. When used, they are commonly held with one hand in a pen grip between the thumb and index finger (sometimes also the middle finger), with the top end resting on the first dorsal interosseous muscle at the webspace between the thumb and index finger. Spring tension holds the grasping ends apart until finger pressure is applied. This provides an extended pinch and allows the user to easily grasp, manipulate and quickly release small or delicate objects with readily variable pressure.

من فضلك سجل دخولك أو قم بتسجيل حساب للإجابة على هذا السؤال

5,010 أسئلة

3,549 إجابة

7,340 تعليقات

13,069 مستخدم