ʻĀpana
Mālama nā mea hoʻopalekana wela i nā polymers mai ka hoʻohaʻahaʻa ʻana i nā kemika i hana ʻia e ka wela a i ʻole UV radiation. Loaʻa i kēia mau mea hoʻohui i nā ʻano mea like ʻole, mai nā kemika kūlohelohe maʻemaʻe i nā kopa metala a i nā pūhui organometallic paʻakikī. ʻO ka polymer maʻamau e koi ana i ka hoʻohana ʻana i nā mea hoʻopaʻa wela he polyvinyl chloride (PVC). Eia nō naʻe, pōmaikaʻi nā copolymers o PVC, chlorinated polyvinyl chloride (CPVC), polyvinylidene chloride (PVDC) a me chlorinated polyethylene (CPE) mai kēia ʻenehana. ʻO PVC ka papa koʻikoʻi o nā polymers halogenated e koi ana i kēia mau mea hoʻohui kemika.
Ma ka hana maʻamau, ua hui pū ʻia ka resin PVC me nā mea i makemake ʻia ma lalo o nā kūlana hui ʻana i ka shear kiʻekiʻe e hana i kahi hui maloʻo maloʻo homogeneous. Hiki i nā mea hoʻopalekana wela ke wai a i ʻole ka pauka a hoʻohui ʻia i ka hoʻomaka ʻana o ka pōʻai hui e hāʻawi i ka stabilization i kēia hana. ʻO ka hoʻomaʻamaʻa mua ʻana i ka resin a kokoke i ka mahana hoʻololi aniani e hoʻomaʻamaʻa i ka adsorption o nā mea hoʻohui wai, e hopena i nā waiwai kahe o ka pauka maikaʻi a me ka haʻahaʻa haʻahaʻa o ka puʻupuʻu hope. Ma hope o ka -hana hoʻohuihui, e like me ka extrusion pelletization, e hoʻonui i ka mōʻaukala wela o ka polymer, no laila, koi ʻia nā pae kiʻekiʻe iki o nā mea hoʻopaʻa wela e uku no kēia.
ʻO nā mea hoʻopaʻa wela e pili ana i ka organotin ka mea ʻoi aku ka maikaʻi a me ka hoʻohana pinepine ʻia o PVC stabilizers. He mau hua kēia o ka tin tetravalent. ʻO ka lua i hoʻohana nui ʻia i ka stabilizer ʻo ia ka hui ʻana o ka metala. ʻO kēia mau huahana e hoʻomalu i nā noi PVC maʻalahi ma United States. ʻO nā paʻakai a me nā kopa o ka calcium, zinc, magnesium, barium a me cadmium i hoʻohana ʻia i loko o kēia mau ʻōnaehana stabilizer koʻikoʻi i ka pāʻoihana alkali a me ka alkaline earth metal. Hiki ke hoʻohui ʻia nā pūhui mea ola ʻē aʻe e like me phosphites, epoxides, polyols a me beta{5}}diketones no ka hoʻonui ʻana i ka hana. Hoʻohana pū ʻia nā antimony mercaptan stabilizers.
