Hiki ke hoʻokaʻawale ʻia nā ʻano hopena i hoʻomaka ʻia e ka radiation ma ke ʻano he ʻelua ʻano: (1) crosslinking and scissionand (2) grafting and curing.
ʻO ka crosslinking ka hoʻokumu ʻana i ka pilina intermolecular o nā kaulahao polymer.ʻO ke kiʻekiʻe o ka hoʻopili ʻana e like me ka nui o ka radiation.ʻAʻole pono ia i nā hui unsaturated a i ʻole nā hui hou aʻe.Me kekahi mau ʻokoʻa (e like me nā polymers i loaʻa i nā mea ʻala), ʻaʻole ia e ʻokoʻa me ke ʻano kemika.ʻAʻole ʻokoʻa loa me ka mahana.ʻOiai ua aʻo ʻia ke ʻano o ka hoʻopili ʻana e ka radiation mai kona ʻike mua ʻana, ʻaʻohe ʻae ākea ākea e pili ana i kona ʻano maoli.ʻOkoʻa ke ʻano o ka hoʻopili ʻana me nā polymers pili.ʻO ka mīkini i ʻae ʻia e ke ao holoʻokoʻa e pili ana i ka wehe ʻana o kahi paʻa C-H ma hoʻokahi kaulahao polymer e hana i ka ahydrogen atom, a ukali ʻia e ka unuhi ʻana o kahi ʻātoma hydrogen ʻelua mai kahi kaulahao pili e hana i ka hydrogen molecular.A laila, hui pū nā radical polymeric ʻelua e hana i crosslink. ʻO ka hopena holoʻokoʻa o ka crosslinking ʻo ia ka hoʻonui mau ʻana o ka nuipaʻa o ka polymer me ka nui o ka radiation, e alakaʻi ana i nā kaulahao lālā a hiki i ka wā e hoʻokumu ʻia ai kahi pūnaewele polymer ʻekolu-dimensional ke hoʻopili ʻia kēlā me kēia kaulahao polymer. i kekahi kaulahao.
ʻO ka ʻokoʻa, ʻo ka scission ke kaʻina ʻokoʻa o ka hoʻopili ʻana i kahi e haki ai ka C-C bonds.Hoʻonui ka crosslinking i ka awelika molecular paona oiai ke kaʻina hana hope e hoʻemi ia.Inā kiʻekiʻe ka ikehu o ka pāhawewe, e haki ana ke kaulahao ma ka ʻoki ʻana o ka paʻa C-C.I loko o ka aeratedsolution medium, eia naʻe, ke ala mechanistic o ka scission e hele ma ke ala ʻole.Hoʻokumu ʻia nā radical free thepolymeric e nā radical free solvent, i hana ʻia e ka radiation.ʻO ka hoʻohaʻahaʻa oxidative o nā polymers e pili ana i ka solventused i loko o ka ʻōnaehana.ʻOiaʻiʻo, hoʻokūkū ka polymer degradation me ka oxidation o ka solvent.
ʻO ka grafting kahi ala e hoʻokomo ʻia ai nā monomers ma hope i ke kaulahao polymer kahi e hōʻoiaʻiʻo ai ka polymerization wikiwiki o kahi hui monomer oligomer e hana i kahi uhi, i hoʻopaʻa pono ʻia e nā ikaika kino i ka substrate.Ma ke ʻano maʻalahi loa, ʻo ia ʻano hana e pili ana i nā ʻōnaehana heterogeneous, ʻo ka substrate he kiʻiʻoniʻoni, fiber a i ʻole he pauda, me ka monomer he wai aneat, mahu a i ʻole ka hopena.Aia kekahi pilina pili ma waena o ka grafting a me ka ho'ōla ʻana ʻoiai aia kekahi mau ʻokoʻa.ʻOiaʻiʻo, ʻaʻohe palena manawa no ke kaʻina hana o ka grafting.Hiki iā ia ke lawe i mau minuke, mau hola a i ʻole nā lā, ʻoiai ʻo ka hoʻōla ʻana he hana wikiwiki loa e hana ʻia ma kahi hapa o kekona.I ka grafting, hoʻokumu ʻia nā paʻa covalent C-C akā i ka hoʻōla ʻana, pili pinepine ka hoʻopaʻa ʻana i nā ikaika weakervan der Waals a i ʻole London.Hana ʻia ka hoʻopaʻa ʻana o van der Waals ma kahi mamao kahi liʻiliʻi a ʻaʻohe uhi a hoʻololi a pili pū ʻia me nā ikaika liʻiliʻi.Eia nō naʻe, ʻoi aku ka maikaʻi o ka covalentbonding ma nā wahi liʻiliʻi internuclear a pili pū me ka electron overlap, hoʻololi, a no laila ka ikaika kiʻekiʻe.ʻO kekahi ʻano koʻikoʻi o ka hoʻōla ʻana i nā hopena, ʻo ia ka hiki ke hiki i ka grafting concurrent me ka curing ke alakaʻi i ka hoʻomaikaʻi ʻana i nā waiwai o ka huahana i hoʻopau ʻia, ʻoi aku hoʻi i ka adhesion a me ka maʻalahi.
Hoʻomaka ʻia ka grafting ma nā ʻano ʻokoʻa ʻekolu: (a) pre-irradiation;(b) peroxidation a me (c) ʻenehana irradia-tion like.Ma ka ʻenehana pre-irradiation, ua hoʻomālamalama ʻia ka iwi kuamoʻo polymer mua i loko o ka hakahaka a i ʻole ke alo o kahi kinoea inert e hana i nā radical manuahi.A laila mālama ʻia ka substrate polymer irradiated me ka monomer, ʻo ia ka wai a i ʻole ka mahu a i ʻole he hopena i loko o kahi mea hoʻoheheʻe kūpono.Eia nō naʻe, i ke ʻano o ka grafting peroxidation, ua kau ʻia ka polymer kumu i ka radiation kiʻekiʻe i ke alo o ka ea a i ʻole ka oxygen.ʻO ka hopena ka hoʻokumu ʻana o hydroperoxides a i ʻole diperoxide ma muli o ke ʻano o ka iwi kuamoʻo polymeric a me nā kūlana irradiation.ʻO nā huahana peroxy, i kūpaʻa, ua mālama ʻia me ka monomer i ka wela kiʻekiʻe, kahi e hoʻoheheʻe ai nā peroxides i nā toradicals decomposition, a laila e hoʻomaka i ka grafting.ʻO ka pōmaikaʻi o kēia ʻenehana ʻo ia ka hiki ke mālama ʻia nā peroxyproducts waena no nā manawa lōʻihi ma mua o ka hana ʻana i ka hana grafting.Ma ka ʻaoʻao ʻē aʻe, me ka ʻenehana irradiation like ʻole ka polymer a me nā monomers i ka manawa like e hana i nā radical manuahi a no laila e hoʻohui ʻia.No ka mea, ʻaʻole i ʻike ʻia nā monomers i ka radiation i ka ʻenehana pre-irradiation, ʻo ka pōmaikaʻi ʻike o ia ʻano hana ʻo ia ka manuahi mai ka pilikia o ka homopolymer hoʻokumu ʻia me ka ʻenehana like.Eia naʻe, ʻo ka hemahema o ka ʻenehana pre-irradiation ʻo ia ka ʻoki ʻana o ka polymer base ma muli o kona kuhikuhi ʻana, kahi e hoʻopuka nui ai i ka hoʻokumu ʻana i nā copolymers poloka ma mua o ka graftcopolymers.
Ka manawa hoʻouna: Mei-03-2017