Synthesis and properties of photo controlled pesticide release carrier modified by rapeseed meal

To improve the utilization rate of pesticides and reduce the economic losses and environmental hazards caused by pesticide loss, the self-assembly layer of poly (octadecylsiloxane) (PODS) was prepared by hydrolysis, self-assembly and polycondensation of octadecyltrichlorosilane (OTS) on the surface of rapeseed meal (RSM) with octadecyltrichlorosilane (OTS) and p-aminoazobenzene (AAB) as modifiers. At the same time, AAB with photoisomerism was attached to RSM surface to synthesize RSM-PODS/AAB pesticide carrier with photoresponsiveness. Its structure and composition were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), UV-Vis spectroscopy and contact angle measurement device. The results showed that the loading rate of modified RSM was 21.4% higher than that of original RSM, and the cumulative release rate of pinoxaden was 83% in 72 h in the dark. The cumulative release rate of RSM-PODS/AAB was 95% after UV-Vis irradiation for 4 h and 92% after sunlight irradiation for 6 h. The application results showed that RSM-PODS/AAB loaded with pesticides had good UV-Vis and sunlight controlled release performance. The light responsive lipophilic pesticide carrier could effectively control the drug release behavior through UV-Vis and sunlight response.