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以聚乙二醇(PEG)为液化剂液化木质素,得到液化产物直接合成木质素基聚氨酯预聚体(LLPUPs),并用来改性酚醛泡沫。采用FT-IR对木质素液化产物(LLs)和LLPUPs的结构进行了表征和分析,通过SEM、万能试验机结合热重分析仪研究了LLPUPs对酚醛泡沫的形态,机械性能和热稳定性的影响。结果表明:木质素液化产物的羟值为177~286 mg/g,并随着PEG相对分子质量的增加而下降;添加LLPUPs可以增强酚醛泡沫的压缩强度和比压缩强度,当LLPUP2添加量为9%时,比压缩强度最高,为4.44(Pa·m~3)/g;LLPUP1和LLPUP2添加量为9%时,酚醛泡沫泡孔均匀,当LLPUP1添加量为9%时,比弯曲强度最高,为8.23(Pa·m~3)/g;LLPUPs改性酚醛泡沫与纯酚醛泡沫相比,具有相似的热稳定性。
Lignin is liquefied with polyethylene glycol (PEG) as liquefaction agent to obtain liquefied products to directly synthesize lignin-based polyurethane prepolymers (LLPUPs) and to modify phenolic foam. The structure of lignin liquefaction products (LLs) and LLPUPs was characterized and analyzed by FT-IR. The effects of LLPUPs on the morphology, mechanical properties and thermal stability of phenolic foam were investigated by SEM, TENS and TGA. . The results showed that the hydroxyl value of lignin liquefaction products was 177-286 mg / g and decreased with the increase of molecular weight of PEG. The addition of LLPUPs could increase the compressive strength and specific compressive strength of phenolic foam. When the LLPUP2 content was 9 %, The specific compressive strength is 4.44 (Pa · m ~ 3) / g. When the content of LLPUP1 and LLPUP2 is 9%, the cell density of phenolic foam is even. When the amount of LLPUP1 is 9%, the flexural strength is the highest, Is 8.23 (Pa · m 3) / g. LLPUPs modified phenolic foam has similar thermal stability compared with pure phenolic foam.