不同环境中秸秆/SPI改性脲醛树脂复合材料花盆降解行为

Degradation behavior of straw/SPI modified urea formaldehyde resin composite flowerpots in different surroundings

为研究不同环境中秸秆/大豆分离蛋白(SPI)改性脲醛树脂复合材料花盆的降解性能,采用土壤掩埋(SB)和户外曝露(OE)2种方式对试样进行降解处理,通过力学性能、质量损失和吸水性测试,热重-红外联用(TG-FTIR),SEM和EDS能谱对花盆的结构和性能进行了研究。结果显示:与对照组(US)相比,经SB和OE降解处理12个月后,花盆的抗拉强度分别下降了36.51%和19.92%,抗拉弹性模量分别下降了9.38%和3.92%,断裂伸长率分别减少了41.36%和36.61%,质量损失率分别为13.74%和4.69%,且试样吸水性均增强。TG-FTIR联用分析表明:降解处理后花盆的热解脱气条件变得温和,最大热解峰延后。SEM扫描观察发现:SB处理后花盆表面腐蚀度及形貌变化大于OE处理后的,两者表面C和N含量均显著下降,表明秸秆/SPI改性脲醛树脂复合材料花盆经SB和OE处理后均发生不同程度降解,SB处理后花盆的降解速率高于OE处理后的。

In order to study the degradability of flowerpot made from straw/soy protein isolate(SPI)modified urea formaldehyde resin composites in different surroundings,the specimens were treated by soil burial(SB)and outdoor exposure(OE)methods.Structure and performance of flowerpots were investigated through mechanical properties,mass loss rate and water absorption test,TG-FTIR,SEM and EDS.Results show that,compared with control group(US),after treated with SB and OE for 12 months,respectively,the tensile strength of flowerpots decreases by 36.51%and 19.92%,elastic modulus decreases by 9.38% and 3.92%,the elongation at break decreases by41.36%and 36.61%,respectively.The mass loss rates of the two composites are 13.74%and 4.69%,respectively,and the water absorption of specimens enhance.TG-FTIR results show that degassing condition of pyrolytic reaction of flowerpot after degradation process becomes milder,and the maximum pyrolysis peaks lag.SEM shows the degree of surface corrosion and morphology changes of flowerpots after treated with SB are markedly greater than that of flowerpots after treated with OE,and the content of carbon and nitrogen significantly drops.These results indicate that the straw/SPI modified urea formaldehyde resin composite flowerpots treated with SB and OE have been degraded in different extents and degradation rate of flowerpots treated with SB is faster than that of flowerpotstreated with OE.