echemi logo
Product
  • Product
  • Supplier
  • Inquiry
    Home > Coatings News > Paints and Coatings Market > General knowledge of coating: polymerization principle

    General knowledge of coating: polymerization principle

    • Last Update: 2020-04-03
    • Source: Internet
    • Author: User
    Search more information of high quality chemicals, good prices and reliable suppliers, visit www.echemi.com
    Core tip: types of polymerization 1 Synthesis of polymers from monomers (1) According to the change of composition before and after polymerization, the polymerization can be divided into addition polymerization and polycondensation Addition polymerization -- mainly refers to the polymerization of olefin monomers to open double bonds and add each other to form macromolecules under the attack of active species The composition of monomers and polymers is generally the same Paint knowledge | precautions for wall paint color selection Recommended introduction: when painting the wall, the owner sometimes has difficulty in choosing what color of the wall paint to paint In fact, there is no ugly color in the wall paint, only the disharmonious color matching The use of wall color contains the knowledge of health Too strong color will stimulate people's perception, make people have a sense of fidgety, affect people's mental health Grasp the basic principles of wall color and paint a colorful space 1、 Wall paint color selection notice 1 Light color is generally used for the top surface Light colors make people feel light, dark colors make people feel heavy Usually, the treatment of rooms is from top to bottom, from shallow to deep For example, the ceiling and walls of rooms are white and Coating home news: type of polymerization 1 The reaction of monomer synthesis of polymer (1) according to the change of composition before and after polymerization, the polymerization can be divided into addition polymerization and polycondensation Addition polymerization refers to the polymerization of alkene monomers which open double bonds and add each other to form macromolecules under the attack of active species The composition of monomers and polymers is generally the same For example, polycondensation refers to the polymerization of monomers with two or more reactive functional groups, which generates macromolecules through multiple condensation between functional groups, accompanied by small molecules such as water, alcohol, hydrogen chloride, etc For example: (2) according to the polymerization mechanism, it can be divided into chain polymerization and step polymerization Chain polymerization: the formation of macromolecules usually includes elementary reactions such as chain initiation, chain growth, chain transfer and chain termination Its characteristics are as follows: ① the monomers are mainly alkenes (some heterocyclic compounds and a small amount of aldehydes can also be chain polymerized); ② there are active centers, such as free radicals, anions and cations; ③ chain reaction, the life of active center is short, about 10 -1s, from the formation of active center, chain growth to the formation of macromolecules in an instant; the polymerization system is composed of monomers and polymers, and the purpose of extending the polymerization time is to improve the conversion of monomers, with little change in molecular weight; ④ the composition of polymers and monomers is generally the same In terms of mechanism, most of the addition polymerization belongs to chain polymerization, and they are often replaced In fact, chain polymerization and addition polymerization are classified from different perspectives Therefore, some forms of addition polymerization belong to the gradual polymerization mechanism Step polymerization: the formation of macromolecules is a step-by-step process Its characteristics are as follows: ① there are two or more reactive functional groups in the monomer; ② there are often small molecules separated out along with polymerization, and the composition of polymer and monomer is generally different; ③ the main chain of polymer often has the characteristics of functional groups; ④ Step by step polymerization mechanism - the formation of macromolecules is a step-by-step process, and the degree of polymerization is gradually increased by the reaction of reactive functional groups; similarly, most of polycondensation reactions belong to step-by-step polymerization in terms of mechanism, and they are often used alternatively, but some polycondensation reactions belong to chain mechanism Ring opening polymerization refers to the synthesis of macromolecules by ring opening of heterocyclic monomers The common monomers are cyclic ether, cyclic amide (lactam), cyclic ester (lactone), cyclic siloxane, etc The polymerization mechanism of ring opening polymerization may be chain polymerization or gradual polymerization Macromolecular reaction - in addition to the polymerization of small monomers to synthesize macromolecules, the reaction of reactive functional groups on macromolecular structure can also be used to synthesize new macromolecular compounds This method is actually the chemical modification of existing polymers The synthesis of polyvinyl alcohol is a typical example Due to the unstable existence of vinyl alcohol, it is easy to isomerize into acetaldehyde or ethylene oxide, so the synthesis route of polyvinyl alcohol is: vinyl acetate is first synthesized into polyvinyl acetate (PVAc) by free radical polymerization, and then polyvinyl acetate is formed into polyvinyl alcohol (PVA) by alkaline alcoholysis Home of coatings is specialized in coatings, diatom mud, paint coating, coating technology, fire retardant coating news and coating, diatom mud, paint coating, coating technology, fire retardant coating decoration knowledge and decoration renderings,
    This article is an English version of an article which is originally in the Chinese language on echemi.com and is provided for information purposes only. This website makes no representation or warranty of any kind, either expressed or implied, as to the accuracy, completeness ownership or reliability of the article or any translations thereof. If you have any concerns or complaints relating to the article, please send an email, providing a detailed description of the concern or complaint, to service@echemi.com. A staff member will contact you within 5 working days. Once verified, infringing content will be removed immediately.

    Contact Us

    The source of this page with content of products and services is from Internet, which doesn't represent ECHEMI's opinion. If you have any queries, please write to service@echemi.com. It will be replied within 5 days.

    Moreover, if you find any instances of plagiarism from the page, please send email to service@echemi.com with relevant evidence.