eksposesen long altravailet rediesen
Sapos yu kisim ol rediesen bilong san long san, dispela inap bagarapim plastik bihain long taim. Polima fotodegradesen i save kamap taim ol i no inap lukim ol altraviolet rediesen i gat ol sotpela wevlength i save brukim ol polima sen insait long ol plastik. Ol i kolim dispela olsem proses bilong kisim fotodegradesen. Em i kamap long wanem, ol i kisim rediesen bilong altraviolet na dispela i mekim na ol samting bilong bodi i go daun. Dispela em olsem, strong bilong strong bilong en i no inap kamap gut, kala i senis, krek, lus bilong elongasen na strong bilong tensil, na pes bilong chalking long pes. Olsem, fotodegradesen em UV rediesen i kamapim inap mekim na ol sia bilong gaden i bagarap na bagarap. Na tu, kala bilong ol sia bilong stediam bai kamap olsem chalky, na sampela plastik bai i yelo na bruk tu.
Sampela Karakteristik bilong Ultraviolet Rediesen
Ol i wokim rediesen bilong ultraviolet long 4.6 pesen tasol bilong spektrum bilong san. Em i save skelim long ol nanomita (nm) na mak bilong en long 290 i go inap long 400. Tasol, hap bilong UVB mak i strong tru em ol sotpela wevlength tru namel long 280 na 315 nanomita. Olsem na mak bilong UV rediesen eneji eksposesen (irediesen) i dipen long wanem hap yu stap long en long wol.
wanem samting em i rediesen
Irradiance is the amount of ultraviolet radiant energy incident on a specific area over a given period of time. 1Ly=1 cal/cm 2=4.184 E 4 Joule/m 2 (Ly=Langley) Therefore, for one year of continuous outdoor use in Sudan, the energy transferred to the plastic parts is 220kcal/cm 2 /year, while in Sweden em i 70.
Olgeta plastik i save pilim sampela wevlength long 290-400 nm UV rijon. Olsem na polipropilen i gat tripela maksima long 290-300, 330 na 370 nm. Nailon i stat long 290-315, na PVC homopolimer em 320.
Degredesen bilong ol Polima long UV Rediesen
Polima fotodegradesen i save kamap taim ultraviolet rediesen i kam long san i save kisim ol kemikel grup long polima straksa ol i kolim kromofor. Wanpela kromofor em i "wanpela atom o grup bilong ol atom we presens bilong ol i makim kala bilong wanpela kompaun". Ol polima fomulasen i ken i gat ol narapela samting olsem ol samting olsem ol halogented flame retardant, filler na ol pigmen. Olsem na ol i bin wokim ol UV stebilisa na putim long ol polima bilong daunim wok bilong fotoinitiesen. Ol namba wan tripela kain em UV absorber, ol quencher, na pasim ol amine lait stabilisa (HALS).
1) UV absorber
Ol absorber em ol potostabilisa husat i wok long rot bilong resis wantaim ol kromofor long kisim UV rediesen. Olsem na, dispela absoba i save senisim ol samting nogut UV rediesen i kamap infraret rediesen i no inap bagarapim man o hat i save pinis long rot bilong polima matriks. UV absorber i gat gutpela samting long kisim liklik kos, tasol em i ken gutpela tasol long ol sotpela (2}} tem eksposen. Ol samting bilong kisim long UV em:
Absorber
UV absorber i gat gutpela samting long stap liklik kos, tasol em i ken gutpela tasol long ol sotpela (0}} tem eksposen. Ol samting bilong kisim long UV em:
Kabon blak em i wanpela bilong ol samting ol i save yusim gut tru na ol i save yusim planti taim long kisim UV rediesen.
Narapela UV absorber em rutil titanium oksait, we i wok gut long 300-400 nm mak. Tasol em i no gutpela tumas long sotpela wevlength UVB mak aninit long 315.
Haidroksibensofon
Hydroxyphenyl benzotriazole em i wanpela UV stebilisa ol i save gut long en tu wantaim gutpela samting bilong stap gutpela long ol wok i no gat wok o klia. Ol i no helpim tumas ol liklik hap bilong skin i go daun tru long ol liklik hap aninit long 100 maikron.
Bensofonone bilong PVC
Ol anzotriazol na haidroksifenita bilong ol polikabonet.
Oksalanilid bilong ol poliamides
2) Kwenja
Ol kwen i givim bek amamas stet bilong kromofor i go long graun stet long rot bilong wanpela eneji trensfer proses. Ol eneji trensfer ejen i save wok long rot bilong daunim eksait stet bilong ol kabonil grup i bin kamap long taim bilong fotooksidesen bilong ol plastik samting na long rot bilong bagarap bilong ol haidroperoksait. Dispela i pasim rot bilong brukim ol bon na long pinis bilong en ol i kamapim ol fri radikel.
Nickel quenching agent
Nickel quencher em i kain ol i save yusim planti taim long wok bilong wokim ol piksa bilong gaden. Ol i no save yusim ol dispela samting bikos ol i gat ol hevi metal na ol i givim fainel prodak wanpela tan o grin kala. Tasol, olsem ol amine lait stebilisa i bin pasim yumi toktok long en daunbilo, ol nikel quencher i no wok gut long strongim UV rediesen.
3) Ol samting i pasim rot bilong Amin Lait Stabilisa (HALS)
Ol HALS i longpela{0}}}lasting hat stebilisa we i wok long trapim ol fri radikel i kamap long taim bilong fotooksidesen bilong ol plastik samting. Olsem na HALS i daunim pasin bilong kisim fotodegradesen. Ol i ken tok klia long pasin bilong HALS long rausim ol fri radikel i kamap long rot bilong kisim UV rediesen long rot bilong kamapim ol nitroxyl grup long wanpela proses ol i kolim Denisov saikel.
Nomata we ol HALS prodak we oli stap long komesel oli defren bigwan long strakja, olgeta evriwan oli gat wan 2,2,6,6-tetrametilpiperidine ring strakja. HALS em sampela bilong ol gutpela UV rediesen stebilisa.
Ol Stabilisa bilong UV bilong ol kain kain Plastik
Olsem, HALS i bin helpim wok bilong kamapim polipropilen long kampani bilong wokim ol ka. Taim ol HALS tu i wok gut tru long ol poliolfin, polietilen na poliurethane, ol i no inap yusim olsem ol stabiliser bilong UV rediesen long PVC.
Kombinesen bilong ol UV Stabilisa
From we olgeta trifala wok ya oli wok tru long ol defren mekanisme, plante taem oli joen wetem ol samting ya we oli joen wetem ol samting we oli pulum tingting blong ol man. Olsem, planti taim ol i save yusim ol benzotriazol wantaim HALS bilong pasim ol kala bilong kalaim na kala bilong ol i no ken kamap planti moa.
