Preparation And Application Of Functional Modified Cellulose Membranes For Pesticides Controlled Release

Cellulose,the most abandunt natural materials in the world,has attracted the attention to be the substitution of petrol products due to its biocompatibility and biodegradation.According to the nature of pesticides,cellulose can be designed as a functional membrane for controlled release application by modification.In this paper,we prepared two kind of modified cellulse membranes(anti-UV cellulose membrane and fluorescent cellulose membrane)and studied the application for pestcides controlled releas of these two kind of cellulose membranes.Microcrystalline cellulose was first dissolved in LiCl/DMAc solvent system.4,4'-dihydroxy benzophenone(DHBP)and 2,4-toluene diisocyanate(TDI)were reacted to synthesis a crosslink agent system(DTC).The anti-UV cellulose membrane was prepared by crosslinking cellulose with DTC.The strcture of modified cellulose membrane was confirmed by FT-IR and fluorescent spectra.Tensile strength,thermogravimetric analysis,anti-UV property,hydrophilicity was also performed and could be adjusted by crosslink density.The UV-absorption spertra showed that modified cellulose obtained anti-UV ability by reacting with DHBP.The anti-UV cellulose membrane was tested under UV irradiation to protect four kind of biopesticides.The results showed that the modified cellulose had fantastic anti-UV ability and all the four kind of biopesticides were hardly destructed.According to the degradation of these four kind of biopesticides under sunlight,we can know that the modified cellulose membrane can provide a long-term protection.The accumulation of biopesticides in permeation test was affected by crosslink density,higher crosslink density leading to slower permeantion rate.Fluorescein and naphthylacetic acid(NAA)were first reacted to synthesis fluorescein naphthylacetic ester(FNE).FNE was linked to ethyl cellulose backbone by isopronone diisocyanate to prepare a novel fluorescent cellulose membrane(IECF).The hydrolysis rate of FNE was affected by naphthylacetic acid concentration under pH 7.2 condition.Tensile strength and heat resistant property of membranes were improved after crosslinking and FNE has no influence in these two properties.The chemical release properties,physical release properties and monitoring low concentration of NAA for IECF membrane were tested.The results showed that IECF membrane had the ability of release NAA by hydrolysis of FNE.Permeation rate of NAA through IECF membrane was affected by NAA concentration difference.IECF membrane would be fluorescent with hydrolysis of FNE when NAA concentration was low.The fluorescent light can be observed and used as a monitor for low NAA concentration.In this paper,we can find that functional modified cellulose membrane can be used for controlled release pesticides.Meanwhile,these modified cellulose membranes can also be used as optical materials or photoinitiators.The modified membrane need more research for further application.