Preparation of Organic Crystal Seed and Its Application in Improving the Functional Period of Biodegradable Agricultural Film

Runmeng Qiao,Xin Wang,Wenqing He,Qi Liu,Jialei Liu,Guangjiong Qin

doi:10.3390/cryst11070826

Abstract

White pollution caused by agricultural films has recently attracted great attention. In some areas, the content of micro plastic in the soil has reached 30 kg/ha. The most effective way to solve this problem is to replace traditional polyethylene agricultural films with degradable agricultural films. The consistency between the degradation rate and the crop growth period has become the biggest obstacle for the wide application of such novel agricultural films. In this paper, crystallinity regulation is used to adjust the functional period of degradable agricultural films. In addition, an organic nucleating agent of polyethylenimine (PEI) is selected by doping it to poly(butylene adipate-co-terephthalate) (PBAT) polymers using a double-screw extruder. The PBAT doped with 1 wt% PEI films revealed a significant increase in mechanical properties, water holding capacity, and crystallinity compared with the pure PBAT film. There was a 31.9% increase in tensile strength, a 30.5% increase in elongation at break, a 29.6% increase in tear resistance, a 30.9% decrease in water vapor permeability, and a 3.1% increase in crystallinity. Furthermore, the induction period of PBAT doped with 1 wt% PEI under photoaging (without soil) was about 160 h longer than PBAT film, and the experienced biodegradation in soil (without light) was 1 week longer than PBAT film. Experimental results exhibited that the change of degradation degree was linearly proportional to the degree of crystallinity. This study proposes a convenient, low-cost, and effective method to adjust the crystallinity and change the degradation rate.

Highlights

Biodegradable polymers have attracted a lot of attention due to the environmental problems caused by traditional plastic materials and the depletion of fossil resources [1,2]
Most studies of the biodegradation of poly(butylene adipate-co-terephthalate) (PBAT) have been performed under composting conditions, but our work aims to evaluate the behavior of the composites on the soil surface, as it was more in line with the needs of field application and provides reference
The results show that the addition of PEI markedly improved the mechanical properties of PBAT

Summary

Introduction

Biodegradable polymers have attracted a lot of attention due to the environmental problems caused by traditional plastic materials and the depletion of fossil resources [1,2]. (butylene adipate-co-terephthalate) (PBAT), which is an aliphatic–aromatic copolyester as well as a semi-crystalline copolyester, shows excellent processability, thermal properties, mechanical properties, and biodegradability. To meet the growing needs of more crops and to retard the degradation rate of PBAT, several means have been proposed to delay the degradation time, such as adding ADR chain extender [6], UV absorber [7], and antihydrolytic agent [8], among others. All these methods had a positive effect on delaying the degradation rate of plastic film

Objectives

Methods

Results