Zinthu zomwe zimakhala ndi magulu ambiri a hydroxyl zimatchedwa spolyols.Athanso kukhala ndi ester, ether, amide, acrylic, zitsulo, metalloid ndi zina, pamodzi ndi magulu a hydroxyl.Polyester polyols (PEP) imakhala ndi magulu a ester ndi hydroxylic pamsana umodzi.Nthawi zambiri amakonzedwa ndi condensation reaction pakati pa glycols, mwachitsanzo, ethylene glycol, 1,4-butane diol, 1,6-hexane diol ndi dicarboxylic acid/anhydride (aliphatic kapena zonunkhira).Makhalidwe a PU amadaliranso kuchuluka kwa kulumikizana pakati komanso kulemera kwa ma cell a PEP yoyambira.Ngakhale PEP yokhala ndi nthambi zambiri imapangitsa kuti PU ikhale yolimba komanso kutentha kwabwino komanso kukana kwamankhwala, PEP yokhala ndi nthambi zochepa imapatsa PU kusinthasintha kwabwino (pa kutentha kochepa) komanso kutsika kwa mankhwala.Momwemonso, ma polyols otsika kwambiri a cell amatulutsa PU yolimba pomwe ma polyols olemera amtundu wautali amatulutsa PU yosinthika.Chitsanzo chabwino kwambiri cha PEP yochitika mwachilengedwe ndi mafuta a Castor.Mafuta ena amasamba (VO) mwa kusintha kwamankhwala kumabweretsanso PEP.PEP amatha kutenga hydrolysis chifukwa cha kukhalapo kwa magulu a ester, ndipo izi zimabweretsanso kuwonongeka kwa makina awo.Vutoli litha kuthetsedwa powonjezerapo pang'ono ma carbodiimides.Ma polyether polyols (PETP) ndi otsika mtengo kuposa PEP.Amapangidwa ndi kuwonjezereka kwa ethylene kapena propylene oxide ndi mowa kapena amine zoyambira kapena zoyambitsa pamaso pa asidi kapena chothandizira.PU yopangidwa kuchokera ku PETP imawonetsa kutsika kwa chinyezi komanso Tg yotsika, zomwe zimalepheretsa kugwiritsa ntchito kwambiri zokutira ndi utoto.Chitsanzo china cha ma polyol ndi acrylated polyol (ACP) opangidwa ndi ma polymerization aulere a hydroxyl ethyl acrylate/methacrylate ndi ma acrylics ena.ACP imapanga PU yokhala ndi kukhazikika kwamafuta komanso imaperekanso mawonekedwe a acrylics ku PU yotsatila.Ma PU awa amapeza ntchito ngati zida zokutira.Ma polyols amasinthidwanso ndi mchere wachitsulo (mwachitsanzo, ma acetate achitsulo, ma carboxylates, ma chlorides) kupanga chitsulo chokhala ndi polyols kapena hybrid polyols (MHP).PU yotengedwa kuchokera ku MHP imawonetsa kukhazikika kwamafuta, gloss ndi anti-microbial.Literature imafotokoza zitsanzo zingapo za VO zochokera PEP, PETP, ACP, MHP zomwe zimagwiritsidwa ntchito ngati zida zokutira za PU.Chitsanzo china ndi ma VO opangidwa ndi mafuta a amide diols ndi ma polyols (ofotokozedwa mwatsatanetsatane mu chaputala 20 Mafuta a mbewu opangidwa ndi polyurethanes: kuzindikira), omwe akhala ngati zida zabwino kwambiri zoyambira pakupanga PU.Ma PU awa awonetsa kukhazikika kwamafuta komanso kukana kwa hydrolytic chifukwa cha kupezeka kwa gulu la amide mu diol kapena polyol msana.

Chidziwitso: Nkhaniyi yatengedwa kuchokeraChiyambi cha Polyurethane ChemistryFelipe M. de Souza, 1 Pawan K. Kahol, 2 ndi Ram K.Gupta *,1.Pokhapokha kuyankhulana ndi kuphunzira, osachita zina zamalonda, sikuyimira maganizo ndi malingaliro a kampani, ngati mukufuna kusindikizanso, chonde funsani wolembayo woyambirira, ngati pali kuphwanya, chonde tilankhule nafe nthawi yomweyo kuti tichite kukonza.