淀粉/PBAT可降解地膜在不同环境下老化性能对比

Comparison of aging properties of starch/ PBAT degradable mulching film in different environments

  • 摘要: 为研制全生物降解地膜以减少传统塑料地膜的污染,以热塑性淀粉(TPS)和聚己二酸/对苯二甲酸丁二醇酯(PBAT)为原料,制备了两种原料配比的生物降解地膜TPS/PBAT-A和TPS/PBAT-B,研究其在热老化(60℃、80℃、100℃)和多因素老化(温度、湿度、光照强度分别为40℃-65%-310 W/m2、60℃-65%-310 W/m2和60℃-65%-648 W/m2)的综合性能。未老化前,两种地膜TPS/PBAT-A和TPS/PBAT-B的拉伸强度分别为16.3 MPa 和20.8 MPa,断裂伸长率分别为1222.7%和564.5%。高温热老化后两种地膜力学性能下降,经100℃热老化后,两种地膜TPS/PBAT-A和TPS/PBAT-B的拉伸强度分别降至11.2 MPa和18.2 MPa;TPS/PBAT-B地膜在热老化后表面缺陷相对较少,其性能保留较好。多因素老化下,光照强度对于两种地膜的力学性能的影响较大,在60℃-65%-310 W/m2和60℃-65%-648 W/m2的对比环境中,两种地膜在24天后拉伸强度分别下降23.0%和22.4%;两种地膜在老化时主要表现为地膜的非结晶区先分解,分子链结构遭到破坏,分子断裂后内部空隙的存在使结合质量下降,表面出现多处孔洞和裂纹。

     

    Abstract: In order to develop a biodegradable mulching film to reduce the pollution of traditional mulching film, thermoplastic starch (TPS) and polyadipate/butylene terephthalate (PBAT) were used as raw materials to prepare two biodegradable mulching films TPS/PBAT-A and TPS/PBAT-B with a ratio of raw materials, and study their thermal aging (60℃, 80℃, 100℃) and multi-factor aging (temperature, humidity, and light intensity are 40℃-65%-310 W/m2, 60℃-65%-310 W/m2 and 60℃-65%-648 W/m2). Before aging, the tensile strength of the two mulching films TPS/PBAT-A and TPS/PBAT-B are 16.3 MPa and 20.8 MPa, respectively, and the elongation at break is 1222.7% and 564.5%, respectively. After high temperature thermal aging, the mechanical properties of the two mulching films decreased. After thermal aging at 100℃, the tensile strength of the two mulching films TPS/PBAT-A and TPS/PBAT-B decreased to 11.2 MPa and 18.2 MPa, respectively; TPS/PBAT-B mulching films have relatively few surface defects after thermal aging, and their properties are well preserved. In the comparative environment of 60℃-65%-310 W/m2 and 60℃-65%-648 W/m2, the tensile strength of the two mulching films decreased by 23.0% and 22.4% after 24 days, respectively. When the two kinds of mulching films are aged, the amorphous area of the mulching films decomposes first, the molecular chain structure is destroyed, the existence of internal voids after molecular fracture reduces the bonding quality, and there are many holes and cracks on the surface.

     

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