?url_ver=Z39.88-2004&rft_id=10.3390%2Fpolym13183072&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.au=Amran%2C+U.A.&rft.aulast=Amran&rft.aufirst=U.A.&rft.atitle=Production+of+rigid+polyurethane+foams+using+polyol+from+liquefied+oil+palm+biomass%3A+Variation+of+isocyanate+indexes&rft.issue=18&rft.title=Polymers&rft.date=2021&rft.volume=13&rft.issn=20734360&rft.genre=article