PTMEG

Polytetrahydrofuran is a white waxy solid that is easily soluble in alcohols, esters, ketones, aromatics and chlorinated hydrocarbons, but insoluble in aliphatic hydrocarbons and water. When the temperature exceeds room temperature, it will become a transparent liquid.

Physical Properties

Melting point: 33-36°C

Density: 1g/mL (25°C)

Vapor pressure: <0.01 mm Hg (25°C)

Refractive index: n20/D 1.465

Flash point: >230℉

Glass transition temperature: -76°C

Appearance: White waxy solid, which will become transparent liquid when the temperature exceeds room temperature.

Chemical properties

Easily soluble in alcohols, esters, ketones, aromatics and chlorinated hydrocarbons, insoluble in aliphatic hydrocarbons and water. As molecular weight increases, solubility decreases. At room temperature, PTMEG is hygroscopic. Its water absorption depends on the size of the molecular weight, and can absorb up to 2% of water.

usual format

Production method

Polytetrahydrofuran was first produced in the late 1930s. It is a polymer produced by ring-opening polymerization of tetrahydrofuran. It can only be obtained by cationic polymerization of tetrahydrofuran. The response is as follows:

nC4H8O+H2O====(initiator)====HO-[-C4H8O-]n-H

In the industry, acetic anhydride-perchloric acid, fluorosulfonic acid or oleum is used as an initiator to polymerize tetrahydrofuran into a product with a molecular weight of 600-3000 and a double-terminal hydroxyl group.

Application

Polytetrahydrofuran is mainly used as the soft segment of block polyurethane or block polyether polyester. Block polyurethane rubber made of polytetrahydrofuran with an average molecular weight of 1000 can be used as tires, transmission belts, gaskets, etc.; it can also be used for coatings, artificial leather, films, etc. The obtained block polyether polyester is a thermoplastic elastomer. Polytetrahydrofuran with an average molecular weight of 2000 can be used to make polyurethane elastic fibers. In 2008, it was reported that block polyurethane made of polytetrahydrofuran has good anticoagulant properties and can be used as a medical polymer material.

Precautions

The following is an elaboration from two aspects of packaging, storage and transportation and fire extinguishing measures.

Packaging, storage and transportation

It should be stored in completely closed tanks or other containers sealed with dry nitrogen. Tanks must be equipped with external or internal heating to maintain a temperature of approximately 50°C. The solidified PTMEG can be heated at about 70°C for 24 hours to fully melt it, but it should not be stored at 90°C for a long time.

Store in a cool, dry and well-ventilated place, away from fire, sparks and open flames. Because PTMEG is hygroscopic and prone to oxidation, it is important to avoid exposure to moisture and air. To prevent static electricity, the shipping container should be grounded. Gloves and protective glasses should be worn during loading and unloading to avoid contact with eyes and skin; soap and water should be used to wash after finishing the work.

Fire fighting measures

In case of fire, extinguish with water spray, alcohol foam, dry chemical or carbon dioxide fire extinguisher.