ikpughe na ultraviolet radieshon
Ikpughe na radieshon ultraviolet nke anyanwụ nwere ike imebi plastik ka oge na-aga. Nrụpụta foto polymer na-apụta mgbe radieshon ultraviolet na-adịghị ahụ anya nke nwere obere ogologo wavelength na-akụda ụdọ polymer na rọba. Nke a ka a na-akpọ usoro mmebi ihe. A na-ebute ya site na ikpughe na radieshon ultraviolet ma na-ebute mbelata ihe onwunwe anụ ahụ. Ndị a gụnyere mfu nke ike mmetụta, mgbanwe agba, mgbawa, mfu elongation na ike tensile, na chalking elu. Dịka ọmụmaatụ, mmebi foto nke UV radieshon kpatara nwere ike ime ka oche ndị dị n'ubi mebie ma ghọọ nkụ. Na mgbakwunye, agba nke oche stadium ga-apụta chalky, ụfọdụ plastik ga-adịkwa edo edo ma gbawaa.
Àgwà ụfọdụ nke Ultraviolet Radiation
Ultraviolet radieshon na-eme naanị 4.6 pasent nke ụdịdị dị iche iche nke anyanwụ. A na-atụ ya na nanometers (nm) wee malite na 290 ruo 400. Otú ọ dị, akụkụ kachasị ike na nso UVB bụ obere ogologo wavelength n'etiti 280 na 315 nanometers. Ya mere, ọnụọgụ ọkụ ọkụ UV radieshon (irradiation) dabere na ebe ị nọ n'ụwa.
Kedu ihe bụ irradiation
Irradiance bụ ọnụọgụ ọkụ ọkụ ultraviolet na-eme n'otu mpaghara n'ime oge e nyere . 1Ly {{1} cal/cm 2=4.184 E 4 Joule/m 2 (Ly=Langley) Ya mere, maka otu afọ nke na-aga n'ihu n'èzí na Sudan, ike na-ebufe na akụkụ plastik bụ 220k / afọ na Sweden.
Plastic ọ bụla na-enwe mmetụta maka ụfọdụ ebili mmiri na mpaghara 290-400 nm UV. Ya mere, polypropylene nwere atọ maxima na 290-300, 330 na 370 nm. Naịlọn sitere na 290-315, ebe PVC homopolymer bụ 320.
Mmebi nke Polymers site na UV Radiation
Polymer photodegradation na-eme mgbe radieshon ultraviolet sitere na anyanwụ na-etinye uche na otu kemịkalụ n'ụdị polymer a na-akpọ chromophores. A chromophore bụ "atom ma ọ bụ otu nke atọm nke ọnụnọ ha na-ekpebi agba nke ngwakọta". Usoro polymer nwere ike ịgụnye mgbakwunye ndị ọzọ dị ka ihe na-egbochi ire ọkụ halogenated, ihe ndochi na pigmenti. Ya mere, emepụtara UV stabilizers ma tinye ya na polymers iji kwụsị usoro photoinitiation. Ụdị atọ mbụ bụ ihe ndị na-ekpo ọkụ UV, ndị na-emenyụ ọkụ, na ihe mgbochi amine light stabilizers (HALS).
1) UV absorber
Absorbers bụ fototabilizers nke na-arụ ọrụ site na asọmpi na chromophores iji nweta radieshon UV. Ya mere, onye na-etinye ihe na-atụgharị na-agbanwe radieshon UV na-emerụ ahụ ka ọ bụrụ radieshon infrared na-adịghị emerụ ahụ ma ọ bụ okpomọkụ nke na-esi na matriks polymer gbasaa. UV absorbers nwere uru nke ịbụ ọnụ ala dị ala, mana nwere ike dabara naanị maka mkpirisi mkpughe{2}}. UV absorbers gụnyere:
Ọfụfụ
Ndị na-ebu UV nwere uru nke ịbụ ọnụ ala dị ala, mana ọ nwere ike dabara naanị maka mkpughe - obere oge. UV absorbers gụnyere:
Carbon ojii bụ otu n'ime ihe ndị na-anabata ụzarị ọkụ UV kachasị dị irè na nke a na-ejikarị.
Ihe ọzọ na-ekpuchi UV bụ rutile titanium oxide, nke dị irè na 300-400 nm nso. Agbanyeghị, ọ baghị uru na oke ikuku UVB dị mkpụmkpụ dị n'okpuru 315.
Hydroxybenzophenone
Hydroxyphenyl benzotriazole bụkwa onye ama ama UV stabilizer na uru nke ịdị mma maka ngwa na-anọpụ iche ma ọ bụ doro anya. Hydroxyphenylbenzotriazoles adịghị uru nke ukwuu na mkpa akụkụ n'okpuru 100 microns.
Benzophenone maka PVC
Anzotriazoles na hydroxyphenyltriazines maka polycarbonates.
Oxalanilide maka polyamides
2) Quencher
Quenchers na-eweghachi ọnọdụ obi ụtọ nke chromophore na ala ala site na usoro nnyefe ike. Ndị na-ebufe ike na-eme ihe site n'ịkwụsị ọnọdụ obi ụtọ nke otu carbonyl nke etolite n'oge photooxidation nke ihe plastik na site na mwepu nke hydroperoxides. Nke a na-egbochi imebi nkekọ na n'ikpeazụ guzobe nke free radicals.
Ihe na-egbochi nickel
Nickel quencher bụ ụdị a na-ejikarị eme ihe nkiri ọrụ ugbo. A naghị eji ihe ndị a eme ihe n'ihi na ha nwere ọla dị arọ ma nye ngwaahịa ikpeazụ ka ọ bụrụ tan ma ọ bụ agba ndụ ndụ. Otú ọ dị, dị ka ihe mgbochi amine ìhè stabilizers a tụlere n'okpuru ebe a, nickel quenchers adịghị arụ ọrụ n'ikwado UV radieshon.
3) Ihe mgbochi Amine Light Stabilizer (HALS)
HALS bụ ogologo ihe na-eme ka okpomọkụ na-adịgide adịgide- na-arụ ọrụ site na ọnyà free radicals a kpụrụ n'oge photooxidation nke plastik. HALS si otú a kpachie usoro mmebi foto. Enwere ike ịkọwa ikike HALS iji kpochapụ radicals n'efu na-esite na ntinye nke radieshon UV site na nhazi nke otu nitroxyl na usoro a maara dị ka okirikiri Denisov.
Ọ bụ ezie na ngwaahịa HALS dị na azụmaahịa dị iche iche na nhazi ya, ha niile nwere nhazi mgbanaka 2,2,6,6-tetramethylpiperidine. HALS bụ ụfọdụ ndị ọkachamara UV radieshon stabilizers.
UV Stabilizers maka Plastics dị iche iche
Dịka ọmụmaatụ, HALS enyela aka na mmepe nke polypropylene na ụlọ ọrụ ụgbọ ala. Ọ bụ ezie na HALS na-arụkwa ọrụ nke ọma na polyolefins, polyethylene na polyurethane, enweghị ike iji ha dị ka ihe nkwụnye maka radieshon UV na PVC.
Ngwakọta nke UV Stabilizers
Ebe ọ bụ na ọrụ atọ ahụ na-arụ ọrụ site na usoro dị iche iche, a na-ejikọtakarị ha n'ime ihe mgbakwunye ọkụ ọkụ UV synergistic. Dịka ọmụmaatụ, a na-ejikarị benzotriazoles na-ejikọta ya na HALS iji gbochie ịda mbà n'obi na mwepu na sistemu agba.
