He aha ka Fluoropolymer?

ʻO ka Fluoropolymer ka mea maʻamau ka polymer olefinic i loaʻa i nā monomers olefinic hapa a i ʻole fluorinated piha e like me vinylidene fluoride (CH2¼CF2) a me tetrafluoroethylene (TFE) (CF2¼CF2).Ua uhi ʻia kēia mau polymers i nā kikoʻī nui i kekahi mau kuhikuhi.ʻO nā polymers fluorinated kūikawā ʻē aʻe he per-fluoroethers, fluoroacrylates, a me nā fluorosilicones i hoʻohana ʻia i ka leo liʻiliʻi loa ma mua o nā fluoropolymers olefinic.

Loaʻa nā fluoropolymers pāʻoihana i nā homopolymers a me nā copolymers.Loaʻa i nā Homopolymers he 99% a ʻoi aku paha ma ke kaupaona ʻana i hoʻokahi monomer a me 1% a i ʻole ka liʻiliʻi ma ke kaupaona ʻana o kekahi monomer e like me ka hui ʻana e ka American Society for Testing Materials (ASTM).Loaʻa i nā copolymers ma mua o 1% a ʻoi aʻe paha ma ke kaumaha o hoʻokahi a ʻoi aku nā comonomers.Hoʻokumu ʻia nā fluoropolymers pāʻoihana nui ma luna o ʻekolu monomers:

TFE, vinylidene fluoride (VF2), a me ka chlorotrifluoroethylene (CTFE).ʻO nā laʻana o nā comonomers he perfluoromethyl vinyl ether (PMVE), perfluoroethyl vinyl ether (PEVE), perfluoropropyl vinyl ether (PPVE), hexafluoropropylene (HFP), CTFE, perfluorobutyl ethylene (PFBE), a me nā monomers exotic e like me 2,2-bistri-fluoromethyl. -4,5-difluoro-1,3-dioxole.

ʻO kahi lula maikaʻi e hoʻomanaʻo ai, ʻo ka hoʻonui ʻana i ka ʻike fluorine o kahi mole polymer e hoʻonui ai i kona kūpaʻa kemika a me ka hoʻoheheʻe, ke kūpaʻa ahi, a me ka photostability;hoʻomaikaʻi i kona mau waiwai uila e like me ka haʻahaʻa dielectric mau;hoʻohaʻahaʻa i ke koena o ka friction;hoʻonui i ka helu heheʻe;hoʻonui i kona kūpaʻa wela;a hoʻonāwaliwali i kona mau mea hana.Hoʻemi maʻamau ka hoʻoheheʻe ʻana o nā polymers i nā solvents ma o ka hoʻonui ʻana i ka ʻike fluorine o ka mole.

Hoʻokaʻawale Fluoropolymer

ʻO ka loaʻa ʻana o PTFE ma 1938 e Roy Plunkett o DuPont Company i hoʻomaka i ke au o nā fluoropolymers. Ua loaʻa i ka PTFE nā kaukani o nā noi no kāna mau waiwai kūʻokoʻa.Ua hoʻomohala ʻia nā ʻano fluoroplastics mai ka loaʻa ʻana o PTFE.He nui nā ʻoihana e hana i kēia mau plastik a puni ka honua.Hoʻokaʻawale ʻia nā Fluoropolymers i ʻelua mau papa o nā polymers perfluorinated a hapa fluorinated.ʻO nā fluoropolymers perfluorinated he mau homopolymers a me nā copolymers o TFE.Hiki i kekahi o nā comonomers ke loaʻa i kahi mea liʻiliʻi ma waho o C a i ʻole F.

Moʻolelo Hoʻomohala Polymer

ʻAʻole hiki ke hana ʻia ka PTFE e nā ʻenehana hoʻoheheʻe hoʻoheheʻe ma muli o kona kiʻekiʻe viscosity.Ua hoʻomohala ʻia nā fluoropolymers hiki ke hoʻoheheʻe ʻia e ka copolymerization o TFE.ʻO FEP, he copolymer o TFE a me HFP, he haʻahaʻa haʻahaʻa ka wela hoʻohana mau ma mua o ka PTFE (200 C vs. 260 C) ma muli o ka pōʻino o nā waiwai mechanical.PFA, he copolymer o TFE me PPVE a i ole PEVE, e haawi i ka thermal stability, melt-processibility a me ka kiekie hoomau hoohana wela 260 C. ʻO ka FEP a me ka PFA i manaʻo ʻia he perfluoropolymers.

ʻOi aku ka ikaika o nā copolymers o ka ethylene me ka tetrafluoroethylene (ETFE) a me ka chlorotrifluoroethylene (ECTFE) ma mua o nā perfluoropolymers, i hui pū ʻia me nā tradeoffs o ka hōʻemi ʻana i ko lākou kūpaʻa kemika a me ka hoʻohana mau ʻana i ka mahana a me ka piʻi ʻana o ka coefficient o friction.

Hiki ke hoʻoheheʻe ʻia nā copolymers Amorphous o TFE i loko o nā mea hoʻoheheʻe halogenated kūikawā a hiki ke hoʻopili ʻia i nā ʻili e like me ka hopena polymer e hana i nā ʻili lahilahi.ʻO ka uhi maloʻo e like me ke kūpaʻa i ka aneane like me ka nui o nā kemika e like me PTFE.