Study On The Preparation And Properties Of High-barrier PBAT/Layered Nano-inorganic Composite Mulch Films

In recent years,agricultural mulching plastic films have been widely used.However,the so called “white pollution” caused by those non-biodegradable films has serious adverse effects on the sustainable development of agriculture.The use of biodegradable materials to replace traditional plastics is a new trend of agricultural film development.Due to the structural defects of biodegradable materials,they generally have poor water retention performance.Therefore,improving the performance of biodegradable materials is one of the highlights in current scientific researches.As a widely used biodegradable material,poly(butylene adipate-co-terephthalate)(PBAT)has good ductility,elongation at break,good heat resistance and impact resistance.In this paper,PBAT acted as matrix material,while MMT and mica were used as fillers to prepare agricultural mulching composite films.The composite films were prepared by coating and solution casting methods,respectively.The microstructure,water retention property,Mechanical properties,light transmission,thermal stability and degradation properties were studied systematically.(1)PBAT/MMT composite film was prepared by coating method.The effect of MMT content on the properties of the film was studied.It showed the addition of MMT could improve water retention capacity of the composite films.When the mass fraction of MMT was 4%,the water retention capacity of composite film was 15.24% higher than that of pure PBAT.Meanwhile,MMT could improve the mechanical properties of the composite films,as well as the film melting temperature and crystallization temperature,while the light transmittance decreased.Based on the soil degradation experiments,it is found that,in the initial degradation,the addition of a small amount of MMT could reduce degradation rate of composite films.MMT-D1821 was prepared by surface modification of MMT with dioctadecyldimethylammonium chloride(D1821),and PBAT/MMT-D1821 composite films were prepared by coating and casting methods,respectively.It showed that under the same adding amount,the water retention property of modified composite film was obviously improved.When MMT-D1821 were added at 5wt% and 4wt% respectively,the water retention properties of composite films were the best,which were 51.08% and 38.34% higher than that of pure PBAT film and significantly higher than that before the filler modification as well.In addition,compared with PBAT/MMT composite films,the mechanical properties,melting temperature,crystallization temperature and light transmission performance of modified composite films were all improved,while the degradation rate was increased.The comprehensive performances of composite films were improved,and the comprehensive performances of PBAT/MMT-D1821 composite films prepared by coating method were better than that prepared by casting method.(2)PBAT/Mica composite film was prepared by coating method,and the effect of Mica content on the film properties was studied.It showed the addition of Mica could improve water retention capacity of composite films.When the mass fraction of Mica was 3%,the water retention capacity of composite film was 24.59% higher than that of pure PBAT.At the same time,Mica could improve the mechanical properties of composite film,as well as the melting temperature and crystallization temperature increased,but the material transmittance decreased.Soil degradation experiments found that in initial degradation,the addition of a small amount of Mica could reduce the rate of degradation of composite films.Mica-SDBS was prepared by the modification of Mica with sodium dodecyl benzene sulfonate(SDBS),and the PBAT/Mica-SDBS composite films were prepared by coating method and casting method respectively.It showed that under the same adding amount,the water retention property of modified composite film was obviously improved.When the amount of Mica-SDBS was 5wt%,the water retention properties of corresponding composite films were the best,which were 45.13% and 39.53% higher than that of pure PBAT respectively,which was significantly higher than that before the filler modification.In addition,compared with PBAT/Mica composite films,the mechanical properties of composite films remained stable after organic modification,the melting temperature and crystallization temperature increased,the light transmission performance improved,and the degradation rate was accelerated to some extent.The comprehensive performance of PBAT/Mica-SDBS composite films prepared by coating method was better.