Cassava residue was liquefied by using ethylene glycol(EG), ethylene carbonate, propylene carbonate and polyethylene glycol(molecular weight: 400 g/mol) as the liquefaction reagent respectively at the temperature of 1...Cassava residue was liquefied by using ethylene glycol(EG), ethylene carbonate, propylene carbonate and polyethylene glycol(molecular weight: 400 g/mol) as the liquefaction reagent respectively at the temperature of 130-170 ℃ with sulfuric acid as the catalyst. The influences of liquefaction parameters, such as the type of liquefaction reagents, mass ratio of EG/cassava residue, liquefaction temperature and time on the properties of the products were discussed. The optimum liquefaction conditions were obtained when the mass ratio of EG/cassava residue was 6:1(w/w), the liquefaction temperature was 150 ℃, the liquefaction time was3 h and the mass fraction of concentrated sulfuric acid/EG was 2.5 wt%. The hydroxyl numbers and residue content of the liquefied products at optimal conditions were 1 137 mgKOH/g and 0.43%, respectively. FT-IR spectrum showed that the liquefaction product of cassava residue was polyether polyol and could be used to prepare polyurethane material or alkyd resins.展开更多
Bio-polyol is considered as a core material to synthesize eco-friendly polyurethane products.However,one of the popular bio-polyols,polytrimethylene ether glycol(PO3G),is reluctant to crystallize and therefore exhibit...Bio-polyol is considered as a core material to synthesize eco-friendly polyurethane products.However,one of the popular bio-polyols,polytrimethylene ether glycol(PO3G),is reluctant to crystallize and therefore exhibits a cold crystallization behavior.This abnormal behavior causes unstable mechanical properties at low-temperature and limits its applications in shape memory devices where crystallization is an essential mechanism.To analyze the unusual phenomenon,we compared different ether polyols focusing on symmetry characteristics and the evenodd effect of carbon backbones.It is found that PO3G has a slow crystallization rate because its ether linkages require specific chain arrangement for attractive interactions.Consequently,a thermal learning mechanism is developed to restore the normal crystallization behavior of elastomers synthesized from the bio-polyol.Repetitive heating and cooling cycles with high-temperature annealing induce urethane exchange reaction and reconstruct the chain orientations for fast crystallization.Results suggest the degree of crystallizations in polyurethane elastomer can be precisely controlled by introducing repetitive thermal treatments to enhance the potential applications of bio-polyols in polymer industries.展开更多
以桐油和3-氨基丙基三乙氧基硅烷(APTES)为原料制备阻燃型桐油基多元醇(PTOA),用PTOA替代常规硬泡聚醚4110制备了一系列聚氨酯硬泡。通过FT-IR和1H-NMR对PTOA进行结构表征,并对聚氨酯硬泡进行热失重分析和其他性能测试,研究了PTOA用量...以桐油和3-氨基丙基三乙氧基硅烷(APTES)为原料制备阻燃型桐油基多元醇(PTOA),用PTOA替代常规硬泡聚醚4110制备了一系列聚氨酯硬泡。通过FT-IR和1H-NMR对PTOA进行结构表征,并对聚氨酯硬泡进行热失重分析和其他性能测试,研究了PTOA用量对聚氨酯硬泡性能的影响。结果表明,环氧化桐油酸甘油单酯(EGTO)通过与APTES发生开环反应得到PTOA;随着PTOA替代聚醚4110的量增加,聚氨酯硬泡的初始分解温度降低,第二、三阶段的最大热失重速率温度降低而对应的速率分别减小和增大;泡沫压缩强度先增大后减小,当PTOA替代量为40%时,泡沫的压缩强度可达最高值350 k Pa;当PTOA用量从0到完全替代聚醚4110时,泡沫的极限氧指数由19. 1%提高至23. 0%。展开更多
基金Funded by the National Natural Science Foundation of China(No.51503041)the Natural Science Foundation of Fujian Province,China(No.2018J01752)
文摘Cassava residue was liquefied by using ethylene glycol(EG), ethylene carbonate, propylene carbonate and polyethylene glycol(molecular weight: 400 g/mol) as the liquefaction reagent respectively at the temperature of 130-170 ℃ with sulfuric acid as the catalyst. The influences of liquefaction parameters, such as the type of liquefaction reagents, mass ratio of EG/cassava residue, liquefaction temperature and time on the properties of the products were discussed. The optimum liquefaction conditions were obtained when the mass ratio of EG/cassava residue was 6:1(w/w), the liquefaction temperature was 150 ℃, the liquefaction time was3 h and the mass fraction of concentrated sulfuric acid/EG was 2.5 wt%. The hydroxyl numbers and residue content of the liquefied products at optimal conditions were 1 137 mgKOH/g and 0.43%, respectively. FT-IR spectrum showed that the liquefaction product of cassava residue was polyether polyol and could be used to prepare polyurethane material or alkyd resins.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(RS-2024-00451587)supported by Post-plastic Specialized Graduate Program through the Korea Environmental Industry&Technology Institute(KEITI)funded by the Ministry of Environment(MOE).
文摘Bio-polyol is considered as a core material to synthesize eco-friendly polyurethane products.However,one of the popular bio-polyols,polytrimethylene ether glycol(PO3G),is reluctant to crystallize and therefore exhibits a cold crystallization behavior.This abnormal behavior causes unstable mechanical properties at low-temperature and limits its applications in shape memory devices where crystallization is an essential mechanism.To analyze the unusual phenomenon,we compared different ether polyols focusing on symmetry characteristics and the evenodd effect of carbon backbones.It is found that PO3G has a slow crystallization rate because its ether linkages require specific chain arrangement for attractive interactions.Consequently,a thermal learning mechanism is developed to restore the normal crystallization behavior of elastomers synthesized from the bio-polyol.Repetitive heating and cooling cycles with high-temperature annealing induce urethane exchange reaction and reconstruct the chain orientations for fast crystallization.Results suggest the degree of crystallizations in polyurethane elastomer can be precisely controlled by introducing repetitive thermal treatments to enhance the potential applications of bio-polyols in polymer industries.
文摘以桐油和3-氨基丙基三乙氧基硅烷(APTES)为原料制备阻燃型桐油基多元醇(PTOA),用PTOA替代常规硬泡聚醚4110制备了一系列聚氨酯硬泡。通过FT-IR和1H-NMR对PTOA进行结构表征,并对聚氨酯硬泡进行热失重分析和其他性能测试,研究了PTOA用量对聚氨酯硬泡性能的影响。结果表明,环氧化桐油酸甘油单酯(EGTO)通过与APTES发生开环反应得到PTOA;随着PTOA替代聚醚4110的量增加,聚氨酯硬泡的初始分解温度降低,第二、三阶段的最大热失重速率温度降低而对应的速率分别减小和增大;泡沫压缩强度先增大后减小,当PTOA替代量为40%时,泡沫的压缩强度可达最高值350 k Pa;当PTOA用量从0到完全替代聚醚4110时,泡沫的极限氧指数由19. 1%提高至23. 0%。
