Izinto ezinobuninzi bamaqela e-hydroxyl zibizwa ngokuba zii-spolyols.Zisenokuba ne-ester, i-ether, i-amide, i-acrylic, isinyithi, i-metalloid kunye nezinye izinto ezisebenzayo, kunye namaqela e-hydroxyl.Iipolyester polyols (PEP) ziquka i-ester kunye namaqela e-hydroxylic kumqolo omnye.Ngokuqhelekileyo zilungiswa yi-condensation reaction phakathi kwe-glycols, okt.
i-ethylene glycol, i-1,4-butane diol, i-1,6-hexane diol kunye ne-dicarboxylic acid / anhydride (i-aliphatic Polyurethane: Intshayelelo ye-7 okanye i-aromatics).Iipropathi zePU zikwaxhomekeke kwiqondo lokudityaniswa okunqamlezayo kunye nobunzima bemolekyuli bePEP yokuqala.Ngelixa i-PEP ene-branched kakhulu iphumela kwi-PU eqinile enobushushu obuhle kunye nokumelana neekhemikhali, i-PEP encinci ye-branched inika i-PU ngokuguquguquka okuhle (kwiqondo lokushisa eliphantsi) kunye nokuchasana kweekhemikhali.Ngokufanayo, iipolyols ezinobunzima obuphantsi bemolekyuli zivelisa iPU eqinile ngelixa ubunzima obuphezulu bemolekyuli betyhutyha elide buvelisa iPU eguquguqukayo.Umzekelo ogqwesileyo we-PEP eyenzeka ngokwemvelo yiCastor oil.Ezinye i-oyile zemifuno (VO) ngokuguqulwa kweekhemikhali nazo zikhokelela kwi-PEP.I-PEP ichaphazeleka kwi-hydrolysis ngenxa yobukho be
amaqela ester, kwaye oku kukhokelela ekuwohlokeni kweempawu zabo zoomatshini.Le ngxaki inokoyiswa ngokongezwa kwexabiso elincinci le-carbodiimides.Iipolyether polyols(PETP) azibizi kakhulu kunePEP.Ziveliswa ngokongezwa kokusabela kwe-ethylene okanye ipropylene oxide kunye notywala okanye i-amine starters okanye abaqalisi phambi kwe-asidi okanye isiseko se-catalyst.I-PU ephuhliswe kwi-PETP ibonisa ukunyameka okuphezulu kunye ne-Tg ephantsi, ethintela ukusetyenziswa kwabo ngokubanzi kwiingubo kunye neepeyinti.Omnye umzekelo we-polyols i-acrylated polyol (ACP) eyenziwe yi-polymerization yamahhala ye-hydroxyl ethyl acrylate / methacrylate kunye nezinye i-acrylics.I-ACP ivelisa i-PU enozinzo oluphuculweyo lwe-thermal kwaye inikezela ngeempawu eziqhelekileyo ze-acrylics kwisiphumo sePU.Ezi PU zifumana izicelo njengezinto zokugquma.Iipolyols ziphinda zitshintshwe ngeetyuwa zentsimbi (umz., iiacetates zentsimbi, i-carboxylates, iikloridi) zenza isinyithi esiqulethe iipolyols okanye iipolyoli ezixutyiweyo (MHP).I-PU efunyenwe kwi-MHP ibonisa ukuzinza okuhle kwe-thermal, i-gloss kunye nokuziphatha okuchasene ne-microbial.Uncwadi lubika imizekelo emininzi ye-VO esekelwe kwi-PEP, i-PETP, i-ACP, i-MHP esetyenziswa njengezinto zokugquma i-PU.Omnye umzekelo yiVO derived fatty amide diols and polyols (ichazwe ngokweenkcukacha kwisahluko sama-20 Imbewu yeoli esekwe kwi-polyurethanes: ingqiqo), esebenze njengegqwesileyo.
izixhobo zokuqala zokuphuhliswa kwePU.Ezi PU ziye zabonisa ukuzinza okuhle kwe-thermal kunye nokumelana ne-hydrolytic ngenxa yobukho beqela le-amide kwi-diol okanye i-polyol backbone.

Isibhengezo:Inqaku licatshulwe © 2012 Sharmin kunye noZafar, umntu onikwe ilayisenisi u-InTech.Kuphela ukunxibelelana kunye nokufunda, ungenzi ezinye iinjongo zorhwebo, ayimeli iimbono kunye nezimvo zenkampani, ukuba ufuna ukuphinda uprinte, nceda uqhagamshelane nombhali wokuqala, ukuba kukho ukuphulwa, nceda uqhagamshelane nathi ngokukhawuleza ukwenza ukucima ukusetyenzwa.