ʻO kekahi mau mea koʻikoʻi i ka hoʻohaʻahaʻa ʻana i ka uhi polyester

Hoʻopilikia ʻia ka polyester degradation e ka pāhawewe lā, photocatalytic admixtures, ka wai a me ka wai, nā kemika, oxygen, ozone, mahana, abrasion, koʻikoʻi o loko a me waho, a me ka mae ʻana o ka puaʻa. ʻO ka mea nui loa i ka hoʻohaʻahaʻa ʻana i ka uhi:

ka mākū, ka mahana, ka hoʻoheheʻe ʻana, ka pāhawewe UV.

ona mau

Hana ʻia ka hydrolysis i ka wā e ʻike ʻia ai ka plastic i ka wai a i ʻole ka haʻahaʻa.

mahana

Ke hoʻokomo ʻia ka polymer i ka ikehu wela ma mua o ka ikehu paʻa e hoʻopaʻa ai i nā ʻātoma, ua maʻalahi ia e hoʻokaʻawale. ʻO ka hopena, hana ʻia ʻelua macroradicals, a i ʻole nā ​​molekole electron-deficient.
ʻO ka hapa nui o nā plastics he generalloiloi ʻia i loko o ʻekolu mau kūlana o ka ʻike ʻana i ka wela kiʻekiʻe: ke kiʻekiʻe o ka wela no ka manawa lōʻihi, ka wela kiʻekiʻe i kahi manawa pōkole, a i ʻole ka ʻike ʻana i nā mahana kiʻekiʻe a hoʻohaʻahaʻa ʻia, e like me ke ʻano o ka hoʻolaha ʻana i ke ao a me ka pō. hoʻonui ʻia ka mahana, hoʻonui ʻia nā hopena luku e ka hoʻolaha ʻana o UV.

ʻO ka hoʻonāʻana

Ma muli o ka loaʻa ʻana o ka oxygen i ka lewa, ʻo ke ʻano maʻamau o ka hoʻohaʻahaʻa ʻana i ka radiation, photooxidation, loaʻa i nā polymers organik āpau. Eia hou, e hoʻolōʻihi ʻia ke kaʻina hana e ka radiation UV a me nā mahana kiʻekiʻe. Hiki ke wehewehe ʻia ka hopena kemika e ka hoʻouka ʻana o ka oxygen i ka mea paʻa i loko o ke kaulahao polymer, hiki ke hana i nā hui carbonyl a i ʻole crosslink. Hiki ke hoʻohana ʻia nā stabilizers like ʻole e hōʻemi i ka degradation polymer: antioxidants, thermostabilizers, photostabilizers, etc.

Pāhawewe UV

I ka wā e pili ana i nā noi waho, ʻo ka mea nui e hopohopo nei i ka loiloi waiwai ʻo ka hiki ke hoʻohaʻahaʻa ʻia ka lā i ka wā i manaʻo ʻia ai nā plastics no ka hoʻohana ʻana i waho. o ka spectrum a maʻamau e ʻokoʻa me nā kūlana o ka ʻāina i kēlā me kēia lā.
ʻO ka hopena photochemical o ka lā ma luna o kahi mea plastik e pili ana i nā waiwai absorption superficial a me ka ikaika paʻa kemika o ka mea. ʻO nā lōʻihi nalu māmā e pili ana i nā plastics mai 290 a 400 nm. ʻO ka lōʻihi hawewe o ka pāhawewe UV nona ka ikehu photon e pili ana i kahi ikehu paʻa i loko o ke kaulahao polymer hiki ke wāwahi i nā mea paʻa kemika (ma o ke kaulahao scission), hoʻololi i nā waiwai, a no laila ka hana o ka polymer. manaʻo ʻia he 6 nm