Ilimin Abubuwan Marufi - Menene ke Haɓaka Canjin Launuka na samfuran Filastik?

• Lalacewar oxidative na albarkatun ƙasa na iya haifar da canza launin lokacin yin gyare-gyare a babban zafin jiki;
• Rashin launi na launin launi a babban zafin jiki zai haifar da canza launin kayan filastik;
• Halin sinadarai tsakanin masu launi da albarkatun ƙasa ko ƙari zai haifar da canza launi;
• Halin da ke tsakanin additives da atomatik oxidation na additives zai haifar da canje-canjen launi;
• Tautomerization na canza launi a ƙarƙashin aikin haske da zafi zai haifar da canjin launi na samfurori;
• Gurbacewar iska na iya haifar da canje-canje a samfuran filastik.

1. Roba Molding ne ya haifar da shi

1) Lalacewar oxidative na albarkatun ƙasa na iya haifar da canza launin lokacin yin gyare-gyare a babban zafin jiki

Lokacin da zobe na dumama ko farantin dumama na kayan aikin gyare-gyaren filastik koyaushe yana cikin yanayin dumama saboda rashin kulawa, yana da sauƙi don haifar da zafin jiki na gida ya yi yawa, wanda ya sa albarkatun ƙasa ya zama oxidize kuma ya lalace a babban zafin jiki. Ga waɗannan robobi masu zafi, irin su PVC, yana da sauƙi don Lokacin da wannan al'amari ya faru, lokacin da yake da tsanani, zai ƙone ya zama rawaya, ko ma baƙar fata, tare da adadi mai yawa na ƙananan ƙwayoyin ƙwayoyin cuta suna ambaliya.

Wannan lalacewa ya haɗa da halayen kamardepolymerization, bazuwar sarkar almakashi, kau na gefe kungiyoyin da ƙananan kwayoyin nauyi abubuwa.

• Depolymerization

Halin tsinkewar yana faruwa akan mahaɗin sarkar tasha, yana haifar da hanyar haɗin sarkar ta faɗi ɗaya bayan ɗaya, kuma monomer ɗin da aka samar yana saurin canzawa. A wannan lokacin, nauyin kwayoyin halitta yana canzawa a hankali, kamar yadda tsarin jujjuyawar sarkar polymerization ke canzawa. Irin su depolymerization na thermal methacrylate.

• Bazuwar Sarkar Bazuwar (Lalata)

Har ila yau, an san shi da karya bazuwar ko sarƙoƙi da aka karye. Ƙarƙashin aikin ƙarfin inji, hasken wutar lantarki mai ƙarfi, raƙuman ruwa na ultrasonic ko reagents na sinadarai, sarkar polymer ta karye ba tare da tsayayyen ma'auni ba don samar da polymer mai ƙananan ƙwayoyin cuta. Yana daya daga cikin hanyoyin lalata polymer. Lokacin da sarkar polymer ta ƙasƙantar da kai, nauyin kwayoyin halitta yana raguwa da sauri, kuma asarar nauyin polymer yana da ƙananan ƙananan. Misali, tsarin lalata na polyethylene, polyene da polystyrene galibi lalacewa ne bazuwar.

Lokacin da aka ƙera polymers irin su PE a yanayin zafi mai girma, kowane matsayi na babban sarkar na iya karye, kuma nauyin kwayoyin yana raguwa da sauri, amma yawan amfanin ƙasa na monomer kadan ne. Irin wannan amsa ana kiransa almakashin sarkar bazuwar, wani lokacin ana kiransa deradation, polyethylene radicals free radicals da aka kafa bayan sarkar almakashi suna aiki sosai, suna kewaye da karin hydrogen na biyu, masu saurin kamuwa da sarkar sarkar, kuma kusan babu monomers da aka samar.

• Cire abubuwan maye

PVC, PVAc, da dai sauransu na iya jurewa canjin cirewa lokacin da aka yi zafi, don haka tudu yakan bayyana akan ma'aunin thermogravimetric. Lokacin da polyvinyl chloride, polyvinyl acetate, polyacrylonitrile, polyvinyl fluoride, da dai sauransu suka yi zafi, za a cire masu maye gurbin. Ɗaukar polyvinyl chloride (PVC) a matsayin misali, ana sarrafa PVC a zafin jiki da ke ƙasa da 180 ~ 200 ° C, amma a ƙananan zafin jiki (kamar 100 ~ 120 ° C), yana fara dehydrogenate (HCl), kuma yana rasa HCl sosai. da sauri a kusa da 200 ° C. Sabili da haka, yayin aiki (180-200 ° C), polymer yana ƙoƙarin zama duhu a launi da ƙananan ƙarfi.

HCl na kyauta yana da tasiri mai tasiri akan dehydrochlorination, da kuma ƙarfe chlorides, irin su ferric chloride da aka kafa ta hanyar aikin hydrogen chloride da kayan aiki, inganta catalysis.

Kadan cikin dari na abubuwan da ake sha acid, irin su barium stearate, organotin, mahadin gubar, da sauransu, dole ne a ƙara su zuwa PVC yayin sarrafa zafin jiki don haɓaka kwanciyar hankali.

Lokacin da ake amfani da kebul na sadarwa don canza launi na kebul na sadarwa, idan Layer polyolefin akan wayar tagulla ba ta tsaya ba, za a samu koren carbon carboxylate na jan karfe akan mahaɗar polymer-Copper. Wadannan halayen suna haɓaka yaduwar jan ƙarfe a cikin polymer, suna haɓaka haɓakar iskar oxygen na jan karfe.

Saboda haka, domin rage oxidative lalata kudi na polyolefins, phenolic ko aromatic amine antioxidants (AH) ana ƙara sau da yawa don kawo karshen sama dauki da kuma samar da marasa aiki free radicals A ·: ROO·+AH-→ROOH+A·

• Lalacewar Oxidative

Kayayyakin polymer da aka fallasa a cikin iska suna ɗaukar iskar oxygen kuma suna yin iskar oxygen don samar da hydroperoxides, suna ƙara bazuwa don samar da cibiyoyi masu aiki, samar da radicals kyauta, sannan a sami halayen sarkar radical kyauta (watau tsarin iskar oxygenation). Polymers suna fuskantar iskar oxygen a cikin iska yayin sarrafawa da amfani, kuma lokacin da zafi, lalatawar iskar oxygen yana haɓaka.

Thermal hadawan abu da iskar shaka na polyolefins na da free radical sarkar dauki inji, wanda yana da autocatalytic hali kuma za a iya raba uku matakai: farawa, girma da kuma ƙarshe.

Sarkar sarkar da ƙungiyar hydroperoxide ke haifar da ita yana haifar da raguwar nauyin kwayoyin halitta, kuma manyan abubuwan da ke cikin scission sune alcohols, aldehydes, da ketones, wanda a ƙarshe ya zama oxidized zuwa carbonoxylic acid. Carboxylic acid yana taka muhimmiyar rawa a cikin oxidation na karafa. Lalacewar Oxidative shine babban dalilin lalacewar kayan aikin jiki da na inji na samfuran polymer. Ragewar Oxidative ya bambanta tare da tsarin kwayoyin halitta na polymer. Kasancewar iskar oxygen kuma na iya haɓaka lalacewar haske, zafi, radiation da ƙarfin injina akan polymers, haifar da halayen lalata masu rikitarwa. Ana ƙara Antioxidants zuwa polymers don rage raguwar lalacewa.

2) Lokacin da aka sarrafa robobin kuma aka ƙera shi, launin launi yakan lalace, ya ɓace kuma ya canza launi saboda rashin iya jure yanayin zafi.

Alamu ko rini da ake amfani da su don canza launin filastik suna da iyakacin zafin jiki. Lokacin da wannan iyaka zafin jiki ya kai, pigments ko rini za su fuskanci canje-canjen sinadarai don samar da nau'o'in nau'in nau'in nau'in nau'in kwayoyin halitta, kuma tsarin halayen su yana da rikitarwa; daban-daban pigments da daban-daban halayen. Kuma samfurori, ana iya gwada juriya na zafin jiki na pigments daban-daban ta hanyoyin nazari kamar asarar nauyi.

2. Masu canza launi suna amsawa tare da kayan danye

Halin da ke tsakanin masu launi da kayan aiki yana bayyana ne a cikin sarrafa wasu abubuwa masu launi ko rini da albarkatun kasa. Wadannan halayen sunadarai zasu haifar da canje-canje a cikin launi da lalata polymers, ta haka canza kaddarorin samfuran filastik.

• Rage martani

Wasu manyan polymers, irin su nailan da aminoplasts, ƙaƙƙarfan wakilai ne na rage acid a cikin narkakkar yanayi, waɗanda zasu iya ragewa da dushe launuka ko rini waɗanda suka tsaya tsayin daka a yanayin yanayin sarrafawa.

• Musanya Alkali

Alkaline ƙasa karafa a cikin PVC emulsion polymers ko wasu stabilized polypropylenes iya "tushe musayar" tare da alkaline ƙasa karafa a colorants don canza launi daga blue-ja zuwa orange.

PVC emulsion polymer wata hanya ce da VC aka polymerized ta hanyar motsawa a cikin emulsifier (kamar sodium dodecylsulfonate C12H25SO3Na) bayani mai ruwa. Halin ya ƙunshi Na+; domin inganta zafi da oxygen juriya na PP, 1010, DLTDP, da dai sauransu ana ƙara sau da yawa. Oxygen, antioxidant 1010 ne mai transesterification dauki catalyzed ta 3,5-di-tert-butyl-4-hydroxypropionate methyl ester da sodium pentaerythritol, kuma DLTDP an shirya ta hanyar amsawa Na2S ruwa bayani tare da acrylonitrile Propionitrile a karshe an hydrolyzed don samar da thiodipropionitrile. samu ta hanyar esterification tare da barasa lauryl. Har ila yau, martanin ya ƙunshi Na+.

A lokacin gyare-gyare da sarrafa samfuran filastik, ragowar Na+ a cikin albarkatun ƙasa za su amsa tare da launi na tafkin mai dauke da ions karfe kamar CIPigment Red48: 2 (BBC ko 2BP): XCa2 ++ 2Na+ → XNa2+ + Ca2+

• Ra'ayin Tsakanin Pigments da Hydrogen Halides (HX)

Lokacin da zafin jiki ya tashi zuwa 170 ° C ko ƙarƙashin aikin haske, PVC yana cire HCI don samar da haɗin haɗin gwiwa biyu.

Halogen mai ƙunshe da harshen wuta-mai hana polyolefin ko samfuran filastik masu launin harshen wuta suma an lalatar da su HX lokacin da aka ƙera su a babban zafin jiki.

1) Ultramarine da HX dauki

Ultramarine blue pigment wanda aka yadu ana amfani da shi wajen canza launin filastik ko kawar da hasken rawaya, fili ne na sulfur.

2) Copper zinariya foda pigment accelerates da oxidative bazuwa na PVC albarkatun kasa

Za a iya yin oxidized pigments na Copper zuwa Cu + da Cu2+ a babban zafin jiki, wanda zai hanzarta bazuwar PVC.

3) Rushewar ions na ƙarfe akan polymers

Wasu pigments suna da tasiri mai lalacewa akan polymers. Misali, tafkin manganese pigment CIPigmentRed48:4 bai dace da gyare-gyaren samfuran filastik na PP ba. Dalili kuwa shi ne cewa m farashin karfe manganese ions catalyze hydroperoxide ta hanyar canja wurin electrons a cikin thermal oxidation ko photooxidation na PP. Rashin lalacewa na PP yana haifar da haɓakar tsufa na PP; haɗin ester a cikin polycarbonate yana da sauƙi don zama hydrolyzed kuma bazuwa lokacin da zafi, kuma da zarar akwai ions karfe a cikin pigment, yana da sauƙi don inganta lalata; ions karfe kuma za su inganta bazuwar thermo-oxygen na PVC da sauran albarkatun kasa, kuma suna haifar da canjin launi.

Don taƙaitawa, lokacin samar da samfuran filastik, ita ce hanya mafi dacewa kuma mafi inganci don guje wa amfani da launuka masu launi waɗanda ke amsawa da albarkatun ƙasa.

3. Reaction tsakanin colorants da additives

1) A dauki tsakanin sulfur-dauke da pigments da Additives

Sulfur mai ƙunshe da pigments, irin su cadmium yellow (m bayani mai ƙarfi na CdS da CdSe), ba su dace da PVC ba saboda rashin juriya na acid, kuma bai kamata a yi amfani da su tare da abubuwan da ke ɗauke da gubar ba.

2) Martani na mahaɗan da ke ɗauke da gubar tare da ma'aunin sulfur mai ɗauke da sulfur

Abubuwan da ke cikin gubar a cikin chrome yellow pigment ko molybdenum ja yana amsawa tare da antioxidants kamar thiodistearate DSTDP.

3) Reaction tsakanin pigment da antioxidant

Don albarkatun kasa tare da antioxidants, irin su PP, wasu pigments za su kuma amsa tare da antioxidants, don haka raunana aikin antioxidants da kuma sa yanayin zafi na oxygen kwanciyar hankali na albarkatun kasa ya fi muni. Alal misali, phenolic antioxidants suna da sauƙin tunawa da carbon baƙar fata ko amsa tare da su don rasa aikin su; phenolic antioxidants da titanium ions a cikin fararen ko samfuran filastik masu launin haske suna haifar da hadaddun hydrocarbon na phenolic don haifar da launin rawaya na samfuran. Zaɓi maganin antioxidant da ya dace ko ƙara ƙarin abubuwan ƙari, irin su anti-acid zinc gishiri (zinc stearate) ko nau'in phosphite nau'in P2 don hana canza launin farin pigment (TiO2).

4) Reaction tsakanin pigment da haske stabilizer

Tasirin pigments da haske stabilizers, sai dai dauki na sulfur-dauke da pigments da nickel-dauke da haske stabilizers kamar yadda aka bayyana a sama, gaba ɗaya rage tasiri na haske stabilizers, musamman sakamakon hana amine haske stabilizers da azo yellow da ja pigments. Tasirin raguwar barga ya fi fitowa fili, kuma ba shi da kwanciyar hankali kamar mara launi. Babu takamaiman bayani kan wannan lamarin.

4. Ra'ayin Tsakanin Additives

Idan an yi amfani da ƙari da yawa ba daidai ba, halayen da ba a zata ba na iya faruwa kuma samfurin zai canza launi. Misali, Sb2O3 mai ɗaukar harshen wuta yana amsawa tare da sulfur mai ɗauke da anti-oxidant don samar da Sb2S3: Sb2O3+–S–→Sb2S3+–O–

Don haka, dole ne a kula da zaɓin abubuwan ƙari yayin la'akari da ƙirar samarwa.

5. Auxiliary Auto-oxidation Dalilan

Rashin iskar shaka ta atomatik na phenolic stabilizers shine muhimmin abu don haɓaka launin fata ko launin haske. Ana kiran wannan canza launin sau da yawa "Pinking" a cikin ƙasashen waje.

Ana haɗe shi da samfuran oxidation kamar su BHT antioxidants (2-6-di-tert-butyl-4-methylphenol), kuma an yi shi da siffa kamar 3,3′,5,5′-stilbene quinone haske ja dauki samfurin, Wannan discoloration yana faruwa. kawai a gaban oxygen da ruwa da kuma rashin haske. Lokacin da aka fallasa shi zuwa hasken ultraviolet, hasken ja stilbene quinone da sauri ya ruɓe zuwa samfurin zobe ɗaya na rawaya.

6. Tautomerization na Launuka masu launi ƙarƙashin Ayyukan Haske da Zafi

Wasu launuka masu launi suna jurewa tautomerization na tsarin kwayoyin halitta a ƙarƙashin aikin haske da zafi, kamar yin amfani da launi na CIPig.R2 (BBC) don canzawa daga nau'in azo zuwa nau'in quinone, wanda ke canza tasirin haɗuwa na asali kuma yana haifar da samuwar haɗin gwiwa. . raguwa, yana haifar da canjin launi daga ja mai duhu shuɗi-haske zuwa haske orange-ja.

A lokaci guda, a ƙarƙashin catalysis na haske, yana lalata ruwa, yana canza ruwan co-crystal kuma yana haifar da faduwa.

7. Gurbacewar iska ke haddasawa

Lokacin da aka adana ko amfani da samfuran robobi, wasu kayan aiki, ko dayan kayan da ake amfani da su, da ƙari, ko launuka masu launi, za su amsa da danshi a cikin yanayi ko gurɓataccen sinadarai kamar acid da alkalis ƙarƙashin aikin haske da zafi. Ana haifar da haɗaɗɗun halayen sinadarai daban-daban, waɗanda zasu haifar da dushewa ko canza launi na tsawon lokaci.

Ana iya kaucewa ko rage wannan yanayin ta hanyar ƙara masu daidaitawar iskar oxygen ta thermal, masu daidaita haske, ko zaɓin abubuwan haɓaka yanayin juriya mai inganci da pigments.