Polypropylene polymerization mechanism 10, polypropylene polymerization mechanism

nch3-ch=ch2—> ch-ch2]n—

The CH3 carbon-carbon double bond opens, and N molecules are connected to form a polymer substance.

Summary. The principle of propylene polymerization into polypropylene: under the action of the initiator, it is formed into CH3-CH+-CH2, and the electrophilic addition reaction of another propylene is attacked to obtain CH3-CH+-CH2-CH(CH3)-CH2, which can be further chained to form polypropylene, and the -CH2 at the end can be combined with each other to form a longer chain, and finally the reaction is terminated under the action of the reducing agent.

The process by which propylene is formed into polypropylene.

The principle of propylene polymerization into polypropylene: under the action of the initiator, it is formed into CH3-CH+-CH2, and the electrophilic addition reaction of another propylene is attacked to obtain CH3-CH+-CH2-CH(CH3)-CH2, which can be further chained to form polypropylene, and the -CH2 at the end can be combined with each other to form a longer chain, and finally the reaction is terminated under the action of the reducing agent.

Propylene polymerization reaction process.

The reaction equation of propylene polyaddition is CH3-NCH3CH=CH2——-CH-CH2-]-N.

Styrene can be heat-cured for self-polymerization similar to acrylates, as well as peroxidation (MEKP or BPO) or ammonia nitrogen (AIBN) initiation of polymerization. When styrene is polymerized, it is necessary to pay attention to the rate of temperature rise to prevent bursting.

Vinyl and benzene rings in styrene form conjugated double bonds, and the electron cloud is loose, so free radical polymerization, anionic polymerization, cationic polymerization, and coordination polymerization can synthesize PS.

Free radical polymerization is usually used in industry, bulk polymerization is usually used for GPPS and HIPS, and suspension polymerization is usually used for EPS.

In addition, PS can also be used for various active polymerization methods.

EPDM rubber is copolymerized with monoolefin ethylene and propylene to form binary ethylene propylene rubber; EPDM rubber is prepared by copolymerizing ethylene, propylene and a small amount of non-conjugated diene as monomers.

Ethylene propylene rubber is a synthetic rubber with ethylene and propylene as the main monomer, according to the different monomer composition in the molecular chain, there are dibasic ethylene propylene rubber and EPDM rubber, the former is a copolymer of ethylene and propylene, and the base is expressed by EPM, and the latter is a copolymer of ethylene, propylene and a small amount of non-conjugated diene fin third round monomer, expressed by EPDM. The two are collectively known as ethylene propylene rubber, i.e. ethylene propylene rubber (EPR).

Ethylene propylene rubber production technology.

There are three types of solution polymerization method, suspension polymerization method and gas phase polymerization method.

Summary. Polymerization methods for polystyrene include:

Polymerization methods for polystyrene include:

Ontology polymerization. Suspension polymerization method.

In the process of suspension polymerization, the dosage of initiator and dispersant, temperature and stirring speed, and the ratio of monomer and water have a significant impact on the particle size distribution of the beads.

The bulk method is the most important production method, and more than 85% of the world's polystyrene (PS) and impact polystyrene (IPS) are produced by the continuous bulk process. The continuous ontology production unit generally has one or several production lines, with a production capacity of 20 160kt a. By improving the reactor design, relative molecular weight and rubber particle size control and devovolatilization technology, the scale and efficiency of the bulk process line can be made larger.

At present, a large-scale bulk production unit with a single-line capacity of 90 138 kt a has been put into industrial operation, but generally speaking, a single reactor has a capacity of 30 50 kt a.

Propylene can undergo free radical polymerization, but the synthetic material properties are not good. Therefore, propylene is generally coordinated polymerized with Ziegler-Natta catalysts. Propylene polymerization reaction produces polypropylene NCH2=CH-CH3 plus polych-coarson—[-ch-c(CH3)-]n

During the polymerization of propylene radicals, the free radicals are easy to extract hydrogen from the propylene molecule to form low-reactive allyl radicals, so no polymer can be obtained.

Ionic polymerization, since the methyl group is the propellant group. It is not easy to anion polymerization, and the push effect of a methyl group is weak, cation polymerization is also difficult, and the active center is easy to isomerize and become a relatively stable structure, so only oligomers can be generated. Pre-mess polymerization is a reaction process in which polymers are synthesized from monomers.

The low molecular weight raw materials with polymerization ability are called monomers, and the polymerization raw materials with large molecular weights are called macromolecular monomers. If the monomer polymerizes to form an oligomer with a low molecular weight, it is called oligomerization, and the product is called oligomerization. The polymerization of a monomer is called homopolymerization, and the product is called homopolymer.

The polymerization of two or more monomers is called copolymerization, and the product is called copolymer.

The disadvantage is that the dissolution time is longer when the temperature is low, and the excessive dosage will lead to water viscosity, weaken the fluidity of the bucket, and block the dosing pipeline. The advantage is that there are many product models and strong customary scale.

Polyacrylamide has many product models, strong habitual scale, can meet a variety of conditions, small dosage, high efficiency, less sludge generation, no corrosion, and simple follow-up treatment, which has been loved by the majority of users. Although it still has some shortcomings, it does not affect its status as the largest and most extensive flocculant product at present. Until a flocculant product with lower cost and better results was developed, polyacrylamide was the best flocculant product in the water treatment industry.

The production of polyacrylamide round pinhui is based on acrylamide aqueous solution as raw material, under the action of initiator, polymerization reaction, after the completion of the reaction of the polyacrylamide rubber block is cut and cut, granulated, dried and crushed, and finally polyacrylamide products are prepared.

1. Woven products: The PP resin consumed by woven products has always accounted for a high proportion in our country, and it is the largest market for polypropylene consumption in our country, mainly used for the packaging of grain, fertilizer and cement.

2. Injection molded products: Injection molded products are mainly used in small household appliances, daily necessities, toys, washing machines, automobiles and turnover boxes. In recent years, the proportion of consumption in the field of injection molding has risen rapidly, from 17% in 2006 to 22% in 2011, ranking second only to plastic weaving.

3. Film products: polypropylene film mainly includes BOPP, CPP, ordinary packaging film and microporous film, etc., BOPP has many excellent characteristics such as light weight, high mechanical strength, non-toxic, transparent, moisture-proof, etc., and is widely used in packaging, electrical, electronic appliances, tape, label film, film, composite and many other fields, among which the packaging industry is the largest.

4. Fiber products: Polypropylene fiber refers to a fiber product made of polypropylene as raw material through melt spinning. Because polypropylene fiber has many excellent properties, it is increasingly widely used in the three major fields of decoration, industry and clothing, and has become the second largest variety of synthetic fibers.