The disposal of plastics represents a serious problem of environmental sustainability. In agriculture, biodegradable plastic systems can potentially replace the commonly used polyethylene (PE) ones. Several studies have been carried out on commercial biodegradable polymers (BPs) to verify their applicability in mulching or irrigation pipes. However, the effect of UV on their performances and degradation rate in soil has not been investigated in depth. In our recent studies, irrigation tubes and mulch films based on BPs were examined and compared with traditional non-biodegradable materials to verify their biodegradability in soil, before and after UV irradiation. Irrigation tubes were prepared starting from a commercial blend of polylactide/poly(butyleneadipate-co-butyleneterephthalate) (Bio-Flex®) and Mater-Bi® through an extrusion-drawing process and compared to conventional tubes of high-density PE. Mulch films based on BPs (Ecovio® and Mater-Bi®), PE and modified PE with oxo-degradable additive were prepared by film blowing. Irrigation pipes and mulch films were subjected to photoaging with continued exposure to UV radiation and different aging intervals. Mechanical properties, contact angle measurements and soil burial degradation tests [1], at 30 and 50 °C, monitoring the weight loss (WL), were carried out, before and after UV irradiation. Chemical modifications were highlighted by Attenuated Total Reflection-Fourier Transform Infra-Red. The biodegradable tubes showed rheological properties similar to those of traditional ones and mechanical properties compatible with those required by this application. The degradation rate of the Mater-Bi®-based tubes was higher than that of the Bio-Flex®-based ones, but the latter showed greater degradation with increasing temperature. For all the samples, soil degradation appeared to be encouraged by UV exposure. In particular, for the Mater-Bi®-based irrigation tubes the degradation was higher at 30 °C and stimulated after 14 days of UV irradiation. Indeed, the UV irradiation encouraged the disintegration in soil of all the samples promoting a molar mass reduction and hydrophilic end groups, thus increasing surface erosion and WL [2-3]. Predictably, the degradation in soil was higher for BP-based samples than for the PE-based ones.
UV AND SOIL BURIAL DEGRADATION OF MULCH FILMS AND IRRIGATION TUBES FOR AGRICULTURE BASED ON BIODEGRADABLE POLYMER BLENDS
2020
Abstract
The disposal of plastics represents a serious problem of environmental sustainability. In agriculture, biodegradable plastic systems can potentially replace the commonly used polyethylene (PE) ones. Several studies have been carried out on commercial biodegradable polymers (BPs) to verify their applicability in mulching or irrigation pipes. However, the effect of UV on their performances and degradation rate in soil has not been investigated in depth. In our recent studies, irrigation tubes and mulch films based on BPs were examined and compared with traditional non-biodegradable materials to verify their biodegradability in soil, before and after UV irradiation. Irrigation tubes were prepared starting from a commercial blend of polylactide/poly(butyleneadipate-co-butyleneterephthalate) (Bio-Flex®) and Mater-Bi® through an extrusion-drawing process and compared to conventional tubes of high-density PE. Mulch films based on BPs (Ecovio® and Mater-Bi®), PE and modified PE with oxo-degradable additive were prepared by film blowing. Irrigation pipes and mulch films were subjected to photoaging with continued exposure to UV radiation and different aging intervals. Mechanical properties, contact angle measurements and soil burial degradation tests [1], at 30 and 50 °C, monitoring the weight loss (WL), were carried out, before and after UV irradiation. Chemical modifications were highlighted by Attenuated Total Reflection-Fourier Transform Infra-Red. The biodegradable tubes showed rheological properties similar to those of traditional ones and mechanical properties compatible with those required by this application. The degradation rate of the Mater-Bi®-based tubes was higher than that of the Bio-Flex®-based ones, but the latter showed greater degradation with increasing temperature. For all the samples, soil degradation appeared to be encouraged by UV exposure. In particular, for the Mater-Bi®-based irrigation tubes the degradation was higher at 30 °C and stimulated after 14 days of UV irradiation. Indeed, the UV irradiation encouraged the disintegration in soil of all the samples promoting a molar mass reduction and hydrophilic end groups, thus increasing surface erosion and WL [2-3]. Predictably, the degradation in soil was higher for BP-based samples than for the PE-based ones.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
