Polymerization by Addition
Addition polymerization can be divided into two main types:
1- Polymerization with chain growth by free radicals.
2- Ionic polymerization : Anionic polymerization and
Cationic polymerization.
If the aggregates large substitutes, it hinders the polymerization process due to steric hindrance. While If the stereochemistry of the kind that pulls the electrons it would lead to reducing the carbon density electronic connected double bonds , this case polymerization of monomer preferably anionic polymerization, like (Acrylonitrile).
If the aggregates and substitutes (electron donating groups), they increase the electron density at the double bond, and preferably monomer polymerized by cationic polymerization, like polypropylene.
Type of Initiators Used in Free Radical Polymerization
There are many types of initiators which used in addition polymerization for starting this reaction by its decomposition to free radical and active center as following:
Thermal decomposition: The initiator is heated until a bond is homolytically cleaved, producing two radicals (Figure 1). This method is used most often with organic peroxides or azo compounds. At some times this type called (Thermal Catalysts) , such as (benzoyl peroxide) and (cumene peroxide).
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .
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