Polimérisasi: Béda antarrépisi

 

Polimérisasi kondensasi lumangsung nalika monomér kabungkeut ngaliwatan [[réaksi kondensasi]]. Réaksi ieu bisa dihasilkeun ku jalan metakeun molekul-molekul nu ngandung gugus fungsi [[alkohol]], [[amina]], atawa [[asam karboxilat]] (atawa turunan karboxil séjénna). Nalika amina meta jeung asam karboxilat, bakal kawangun [[amida]] atawa beungkeut péptida, kalawan ngaleupaskeun cai (jadina polimérisasi ''kondensasi''). Nya ku prosés ieu asam-asam amino numbu sarta ngagabung jadi protéin, sakumaha dijieunna kevlar.

Sistim tumuwuh hambalan ranté-tumuwuh (Ing. ''chain growth-step growth system'') ngagolongkeun polimér dumasar mékanismena. Najan lolobana polimér kaasup kana golongan métode adisi-kondensasi, tapi aya sababaraha iwal.

 

 

To alleviate inconsistencies in these naming methods, adjusted definitions for condensation and addition polymers have been developed. A condensation polymer is defined as a polymer that involves elimination of small molecules during its synthesis, or contains functional groups as part of its [[backbone chain]], or it [[repeat unit]] does not contain all the atoms present in the hypothetical monomer to which it can be degraded.

== Polimérisasi adisi ==

 

 

[[image:polimérisasi éténa.png|right]]

Inisiasi nyaéta prosés nyipta radikal bébas nu dipikabutuh pikeun propagasi. Radikal bisa dijieun tina molekul péroksida organik, molekul nu mibanda beungkeut tunggal O-O, ku ngaréaksikeun [[oxigén]] jeung [[éténa]]. Hasilna mangrupa molekul nu teu stabil nu gampang pisan dibeulah jadi dua radikal. In an ethene monomer, one electron pair is held securely between the two carbons in a sigma bond. The other is more loosely held in a pi bond. The free radical uses one electron from the pi bond to form a more stable bond with the carbon atom. The other electron returns to the second carbon atom, turning the whole molecule in to another radical.

 

 

Other forms of addition polymerization include cationic and anionic polymerization. While not used to a large extent in industry yet due to stringent reaction conditions such as lack of water and oxygen, these methods provide ways to polymerize some monomers that cannot be polymerized by free radical methods such as polypropylene. Cationic and anionic mechanisms are also more ideally suited for living polymerizations, although free radical living polymerizations have also been developed.

== Polimérisasi kondensasi ==

 

[[de:Polymerisation]]

[[en:polymerization]]

[[pt:Polimerização]]

[[ja:重合反応]]