新型完全生物降解农膜的田间降解性能研究

Degradation of a Novel Completely Biodegradable Mulching Film in Field

研制和开发可降解农膜是解决白色污染最有效的途径。为研究生物降解农膜的田间降解行为,本文系统考察了在自然条件下全生物降解农膜（PLA-PEG共聚物）在新疆石河子地区棉田的降解性能,利用红外光谱、X线衍射、分子量拉伸强度、断裂伸长率以及热重等分析对农膜结构和性能的变化分析检测。实验结果表明：随着铺膜时间的增长,农膜的拉伸强度、断裂伸长率和分子量呈下降趋势;4个月以后,分子量由5.43×10~4降低到了2.5×10~4;农膜的机械性能几乎完全丧失,在不同的方向上拉伸强度分别由24.70、27.49和31.93 MPa降低到了3.17、7.52和3.76 MPa。在正常自然气候条件下4个月内,农膜在田间能基本保持较好性能,具有一定的推广价值。

The research and development of biodegradable mulching films is the most effective way to solve white pollution. Degradation of biodegradable mulching films of PLA-PEG copolymer was systematically investigated under natural conditions in cotton fields in Shihezi.Mechanical and structural properties were studied by tensile strength, elongation at break, average molecular weight,thermal gravimetric analysis,X-ray diffraction,and Fourier transform infrared spectroscopy.The results demonstrated that the tensile strength, elongation at break and the molecular weight were decreased with time in.After about 120 days,the molecular weight was decreased from 5.43×104 to 2.5×104.Mechanieal properties of mulching films were almost completely lost,and the tensile strengths in different directions were decreased from 24.70,27.49 and 31.93 MPa to 3.17,7.52 and 3.76 MPa.Under normal natural climatic conditions,mulching films can maintain basic performance for four months in field, and it has a promotional value.