Ultraviolet absorber yɛ ade a ɛho hia yiye a wɔde ka ho wɔ plastic nneɛma mu. Ɛyɛ stabilizer bi a ɛyɛ adwuma sɛ kanea a ɛma ɛyɛ hare. Ɛde tumi a ɛma ɛyɛ den ba titiriw denam owia hann a ɛyɛ ultraviolet no fã a ɛsɛe ade no a ɛtwetwe na ɛsakra no so. Wɔde ultraviolet absorbers di dwuma titiriw wɔ plastic nneɛma te sɛ mprɛte, nhama, nsu paipu ne nneɛma afoforo a ɛyɛ den mu. Mpɛn pii no, wɔde ultraviolet absorbers nso ka plastic film ahorow ho de siw nkɛntɛnso bɔne a hann a ano yɛ den a ɛwɔ nneɛma a wɔabɔ ho ban so nya no ano anaasɛ ɛtwentwɛn so. nsunsuansoɔ.
ultraviolet rays ne ne nkɛntɛnso a ɛsɛe ade wɔ polymers te sɛ plastic so .
Yɛn nyinaa nim sɛ electromagnetic asorɔkye a efi owia mu ba no trɛw yiye, na mframa a etumi du fam no titiriw ne ultraviolet rays, hann a wotumi hu ne infrared rays. Ahoɔden a ɛwɔ mframa mu no ne asorɔkye tenten no hyia wɔ ɔkwan a ɛne no nhyia so, dodow a asorɔkye no tenten yɛ tiaa no, dodow no ara na ahoɔden no yɛ kɛse. Wɔn mu no, ultraviolet rays a ɛwɔ wavelength range a ɛyɛ 290nm-400nm no na ɛwɔ wavelength a ɛyɛ tiaa sen biara ne ahoɔden a ɛkorɔn sen biara, na ɛsan nso yɛ nea ɛsɛe ade kɛse ma polymers te sɛ plastic. Bond ahoɔden a ɛwɔ organic polymers mu no taa yɛ 290 ~ 400kj/mol, enti ɛyɛ mmerɛw ma ultraviolet rays a wɔsɛe no. Enti, ultraviolet rays ne ade titiriw a ɛka plastic a wɔde yɛ mfonini no. Nanso, ɛsɛ sɛ yɛhyɛ no nsow sɛ polymer nnuru a ɛsono ne nhyehyɛe no wɔ nkate a ɛsono wɔ asorɔkye tenten ahorow a ɛyɛ tenten ne nea ɛyɛ tiaa a ɛyɛ ultraviolet rays ho.
Nea enti a polymer nneɛma te sɛ plastic wɔ su pii a eye kyɛn so no fi wɔn macromolecular nkɔnsɔnkɔnsɔn a ɛware no. Nanso, esiane asorɔkye tenten ne ahoɔden a ɛkorɔn a ɛwɔ ultraviolet mframa mu, wɔ ultraviolet mframa (dodow no ara a oxygen de ne ho hyɛ mu) dwumadi ase nti, polymer nneɛma twetwe ultraviolet mframa akyi, ɛnyɛ den sɛ ɛbɛyɛ tebea a ɛma ɛlɛtrɔnik anigye. Molecules a ɛwɔ saa anigye tebea yi mu no betumi ama photochemical reactions a ɛtoatoa so aba, kyerɛ sɛ, free radical chain reactions, na bere koro no ara mu no, "photoxygen aging" anaa "photooxidation reaction" ba bere a oxidation yɛ oxidation no. Wɔtwitwa polymer no mu macromolecular chains no anaasɛ ɛtwa-ɛde bata ho kodu baabi, a ɛka polymer ade no adwumayɛ tẽẽ, enti nneɛma a ɛkɔ so yɛ kɛse a ɛtoatoa so no pue. te sɛ esum, brittleness, hardening, surface cracking, ne sɛe wɔ mfiridwuma ne anyinam ahoɔden su mu, ma enti awiei koraa no, ɛbɛhwere ne bo a wɔde di dwuma no.
Adwene ne dwumadi a ɛwɔ UV absorber mu .
Polymer nneɛma wɔ molecule nhyehyɛe ahorow, na sɛnea ɛko tia ultraviolet hann no yɛ abɔde mu soronko, a ɛkyerɛ sɛ polymer nneɛma ahorow wɔ "photostability" soronko. Wɔ polymer nneɛma a ɛwɔ nkitahodi a ɛnyɛ den te sɛ nkitahodi abien te sɛ ABS ne SBS fam no, ɛnyɛ den sɛ wɔbɛtwe hann a ano yɛ den a ɛwɔ ultraviolet no mu na ayɛ photooxidation nneyɛe, enti wɔn photostability no nyɛ papa. Nanso wɔ polymer a ɛho tew a nnuru a ɛwɔ mu a ɛyɛ saturated nkutoo wom fam no, ɛntwe hann a ano yɛ den no anaasɛ ɛnyɛ den sɛ ɛbɛtwe, enti ɛyɛ nea ɛyɛ den ma hann a ano yɛ den.
Nanso tebea ankasa ne sɛ saa polymer a ɛho tew yi a ɛwɔ saturated bonds no nni hɔ, efisɛ wɔ mfiridwuma mu adeyɛ kwan a wɔfa so yɛ polymers, te sɛ polymerization, extrusion granulation, injection molding, storage, ne nea ɛkeka ho, a wontumi nkwati sɛ ɛde catalyst residues, efĩ bi te sɛ trace hydroperoxides yɛ sensitive to ultraviole reaction, they will of a ɛtwe adwene si so.
Mprempren UV absorbers ne nea wɔde di dwuma kɛse sen biara a ɛma hann no gyina. Ebetumi atwe a ɛkorɔn na ɛpaw nea ɛkorɔn-ahoɔden ultraviolet hann, na agyae anaasɛ adi ahoɔden a ɛtwetwe no sɛ ɔhyew ahoɔden anaasɛ ɛnyɛ asiane a ɛba fam-ahoɔden mframa a ɛyɛ ahoɔden nsakrae, na ɛnam so asiw chromophore a ɛwɔ plastic no mu no kwan sɛ ɛbɛtwe ultraviolet ahoɔden a ɛkanyan no.
UV absorbers no nkyekyem .
UV absorbers no bi ne nneɛma ahorow pii. Sɛnea wɔahyehyɛ no, nea ɛka ho titiriw ne benzophenones, salicylates, benzotriazoles, acrylonitriles a wɔde asi ananmu, triazines, ne nea ɛkeka ho Nea wɔde di dwuma kɛse wɔ plastic adwuma mu ne benzophenones ne benzotriazoles.
Mprempren benzophenone UV absorbers yɛ UV absorbers a wɔde di dwuma kɛse sen biara. Ɛkame ayɛ sɛ wɔtwe UV no nyinaa. Phototable adwinnade no ne hydroxyl hydrogen a ɛwɔ benzene ring no so ne carbonyl a ɛbɛn no wɔ molecule no mu. Hydrogen a ɛwɔ nipadua no mu no yɛ oxygen ntam, na ɛyɛ chelation ring, na sɛ hann a ɛwɔ ultraviolet hann no mu no twetwe a, molecule no fa ɔhyew wosow mu, hydrogen nkitahodi no bubu, na wobue chelation ring no, ma enti wobetumi adan ultraviolet hann a epira no ayɛ ɔhyew ahoɔden a ɛyɛ hu a asiane biara nni ho no fi adi. Wɔ diphenyl ketone ultraviolet absorber mu no, ɛsɛ sɛ orthoxyl kuw bi wɔ hɔ, anyɛ saa a wontumi mfa nni dwuma sɛ hann a ɛma ɛyɛ den mma polymers. Ananmusifo ahorow a wɔtaa yɛ a ɛyɛ saa ultraviolet absorber yi bi ne UV-531, UV-9 ne nea ɛkeka ho.
Salicylate UV absorbers yɛ UV absorbers a edi kan koraa. Ɛtumi yɛ hydrogen nkitahodi wɔ molecule no mu, n’ankasa tumi a ɛde twetwe ultraviolet hann no sua koraa, na asorɔkye tenten a ɛtwetwe no yɛ teateaa koraa (ɛnnu 340nm). Nanso, bere a wɔatwe ahoɔden dodow bi awie no, molecule a wɔsan hyehyɛ no foforo ba. benzophenone nhyehyɛe a ɛwɔ tumi a emu yɛ den a ɛma hann a ano yɛ den no twetwe, na ɛnam so ma wonya photostabilization tumi a emu yɛ den.
Hann a ɛma benzotriazole ultraviolet absorbers no gyina no te sɛ benzophenones de no, na hydrogen bond chelating ring nso wɔ molecule no mu, a hydroxyl oxygen ne nitrogen na ɛyɛ wɔ triazole kuw no so. Sɛ hann a ano yɛ den no twetwe a, wɔbubu hydrogen no mu anaasɛ ɛdan phototautomer, na ɛdan ahoɔden a ɛyɛ hu a ɛma ahoɔden a ɛwɔ ultraviolet mu no yɛ ɔhyew ahoɔden a asiane biara nni ho. Ananmusifo ahorow a wɔtaa yɛ a ɛyɛ saa ultraviolet absorber yi bi ne UV-P, UV-326, UV-327, UV-329 ne nea ɛkeka ho.
