甲醛交联聚乙烯醇/麦草碱木质素发泡材料的降解性能

研究了化学降解、热降解、生物降解及紫外光降解等对甲醛交联聚乙烯醇（PVA）/麦草碱木质素发泡材料（PLFM）的力学性能和表观密度等物理性能的影响，采用红外光谱（FT-IR）、扫描电子显微镜（SEM）和热重分析（TG/DTG）等方法探讨了降解前后PLFM结构的变化。结果表明：当PLFM中碱木质素质量分数为20%时，经化学、热（150℃）、生物及紫外光降解后，拉伸强度由22.64MPa分别降为5.65、9.05、7.43和7.64 MPa，降解率分别为75.09%、60.02%、67.18%、66.25%。SEM图表明，化学降解和生物降解对PLFM闭孔结构破坏严重，紫外光降解和热降解对PLFM闭孔破坏轻微。化学降解和生物降解后，表观密度从0.183 7g/cm³分别增加到0.216 4g/cm³和0.210 4g/cm³；紫外光降解和热降解后，表观密度分别从0.183 7 g/cm³降为0.177 4和0.176 6 g/cm³。此外，FT-IR和TG/DTG分析表明：经化学、热、生物及紫外光降解后PLFM分子结构均有不同程度破坏，化学降解对PLFM结构的破坏最为严重。

Degradation Performances of Poly(vinylalcohol)/Wheat Straw Alkali Lignin Foaming Material with Formaldehyde Crosslinker

The effects of chemical degradation, thermal degradation, biodegradation and ultraviolet light degradation on the mechanical properties and apparent density of poly(vinylalcohol)(PVA)/wheat straw alkali lignin foaming material(PLFM) with formaldehyde as crosslinker were studied. The structural changes of PLFM after degradation were investigated by FT-IR, SEM and TG/DTG. The results showed that the tensile strength decreased from 22.64MPa to 5.65, 9.05, 7.43 and 7.64MPa, and the degradation rates were 75.09%,60.02%,67.18% and 66.25%, respectively, after chemical degradation, thermal degradation(150℃), biodegradation and ultraviolet light degradation, when the mass fraction of alkali lignin in PLFM was 20%. The SEM images showed that the closed pore structures of PLEM were seriously destroyed by chemical degradation and biodegradation and slightly destroyed by ultraviolet light degradation and thermal degradation. After chemical degradation and biodegradation, the apparent density increased from 0.183 7 g/cm³ to 0.216 4 and 0.210 4 g/cm³ and after ultraviolet light degradation and thermal degradation, the apparent density reduced from 0.183 7 g/cm³ to 0.1774 and 0.176 6 g/cm³. In addition, FT-IR and TG/DTG analysis showed that the molecular structure of PLFM was destroyed in different degree by chemical degradation, thermal degradation, biodegradation and ultraviolet light degradation. The structure of PLFM was most seriously destroyed by chemical degradation.