Polymerization inhibitor

Polymerization inhibitor - Names and Identifiers

Name	Polymerization inhibitor
Synonyms	Polymerization inhibitor

Polymerization inhibitor - Physico-chemical Properties

Use	Use as an anti-aggregation agent

Polymerization inhibitor - Uses and synthesis methods

definition

The polymerization inhibitor is a substance that can completely terminate the free radical polymerization reaction of alkene monomers. The role of polymerization inhibitor: In the unsaturated compound system, the polymerization inhibitor can preferentially interact with free radicals in the system to form non-free radical substances, or form free radicals with low activity and insufficient reinitiation, which can effectively block free radicals Chain polymerization. There are great benefits to the stability, storage and transportation of resin.

polymerization resistance mechanism

According to the effect of inhibiting the polymerization reaction, the substances that will be able to stop each free radical and stop the polymerization reaction until they are completely exhausted are called polymerization inhibitors or inhibitors;

The substance that can only weaken the activity of free radicals and slow down the polymerization reaction, but cannot stop the reaction is called a blocker.

classification

There are many types of polymerization inhibitors. First, they can be divided into two categories: free-based and non-free-based or molecular-based polymerization inhibitors. Non-free-based polymerization inhibitors can be divided into phenolic polymerization inhibitors, ether polymerization inhibitors, quinone polymerization inhibitors, aromatic amine polymerization inhibitors and so on according to different substituents. The main varieties of polymerization inhibitors are introduced below by chemical structure classification.

Phenolic polymerization inhibitors: hydroquinone, p-hydroxyanisole, 2, 6-di-tert-butyl p-cresol, 2, 5-di-tert-butyl hydroquinone, 2-tert-butyl hydroquinone.

quinone inhibitors: p-benzoquinone, methyl hydroquinone (THQ).

Inorganic compound polymerization inhibitor: commonly used are ferric chloride, cuprous chloride, copper sulfate, titanium trichloride, sodium sulfate, ammonium thiocyanate.

development of polymerization inhibitors

the research on polymerization inhibitor is mainly based on the polymerization inhibition of several extremely important organic chemical raw materials such as styrene and acrylate. the development speed of polymerization inhibitor is very fast. it has gone through three or four generations from the first generation of polymerization inhibitor DNP and DNPC, which are very toxic at first, to DNBP, which is widely used at present, and the green environmental protection polymerization inhibitor to replace DNBP. At present, the widely used polymerization inhibitors include hydroquinone, tert-butylcatechol, DNBP and other phenols, diethylhydroxylamine and other amines, 701,702 and other nitrosys, as well as various companies' own brands, such as General Electric's STYREX 310, Narco's 3274, Evonik's E0327, Teton Chemical's S1024, etc. Some currently widely used polymerization inhibitors, such as the polymerization inhibitor DNBP for styrene, have very large toxicity, and the natural reduction time is very long. With the continuous advancement of the concept of green environmental protection, the elimination of chemicals that are not friendly to the environment has been put on the agenda. Some countries have passed legislation to strictly prohibit the use of these polymerization inhibitors. New green and environmentally friendly polymerization inhibitors are beginning to enter industrialization, such as General Electric's STYREX 3316 and Teton Chemical's S0606.

the production of polymerization inhibitor raw materials in the polymerization inhibitor market is mainly distributed in China, the United States, Britain, Germany and other countries with developed chemicals. the main manufacturers are NUPHARM,ADDIVANT,EVONIK, RHOIDA and China's Jiuxin industry, revitalizing the chemical industry and Teton chemical industry. NUPHARM and ADDIVANT mainly produce polymerization inhibitor DNBP, EVONIK mainly produces nitroacyl polymerization inhibitor, RHODIA mainly produces phenolic polymerization inhibitor for storage, Jiuxin Industry is a famous DNBP manufacturer, Zhenxing Chemical is a 701 manufacturer, and Teton Chemical is a manufacturer of water-soluble, oil-soluble and formulated products, and is also the only manufacturer of domestic polymerization inhibitor 702. The use of polymerization inhibitor requires professional knowledge background and strong technical support. The cost of polymerization inhibitor is very small in the whole production process, but it has a great impact on the safety of product production and the stability of operation. Therefore, the background requirements of the company that provides polymerization inhibitor and its supporting technical services are very high. With strong brand effect and technical strength, as well as the protection of complete intellectual property rights, the entire polymerization inhibitor industry is currently basically monopolized in the hands of several giant multinational companies, including General Electric, Narco, Evonik, and some slightly smaller regional companies, such as Newfarm in the United Kingdom, Dovkate in India, Kurita and Berton in Japan. In the entire Chinese market, the polymerization inhibitor market, especially styrene, is firmly controlled by General Electric and Narco. China's local factories can basically only provide polymerization inhibitor raw materials to General Electric or Narco, earning extremely small profits, while General Electric and Narco make huge profits under the protection of brands and patents.

Selection method of polymerization inhibitor

The choice of polymerization inhibitor is mainly to have a higher polymerization resistance efficiency, and its solubility in the system and its adaptability to the resin should also be considered.

Some monomers used in non-photocurable systems also require that the polymerization inhibitor in the monomer can be easily removed by distillation or chemical methods, or can not only act as a polymerization inhibitor at room temperature, but also at the reaction temperature. quickly decompose.

1. It has good miscibility with monomer and resin, and only miscibility can inhibit polymerization.

2. It can effectively prevent the occurrence of polymerization reaction and make the monomer, resin, emulsion or adhesive have sufficient storage period.

3. The polymerization inhibitor in the monomer is easy to remove or does not affect the polymerization activity. It is best to choose an effective polymerization inhibitor at room temperature, and lose the polymerization resistance at an appropriately high temperature, so that the polymerization inhibitor does not need to be removed before use.

For example, tert-butyl catechol and p-phenol monobutyl ether are this type of polymerization inhibitor.

4. does not affect the appearance of the final product.

For example, polymerization inhibitors can affect the appearance of products due to high temperature oxidation and discoloration during the preparation of adhesives.

5. The combination of several polymerization inhibitors can significantly improve the polymerization resistance effect.

Last Update：2024-04-10 22:29:15