The Polymerization Mechanism And Characterizations Of Mulch Film Prepared From Weathered Coals

Mulch films with the functions of thermal insulation, water retention, inhibiting weeds is indispensable in the process of agricultural production. But there are shortcomings in recycling and degradation after the lifecycle.In this study we prepared a kind of biodegradable mulch film by the interaction between humic acid in coal and flexible polymer, providing a new technical route and theoretical basis for the application of humic acid in new supramolecular materials. Firstly, By the single factor experiment and the main factors affecting mulch film performance to establish orthogonal experiment, measuring the influence of different technological conditions on mechanical properties of the mulching film, to determine the optimum preparation conditions. And then analyzing the interaction of various components in the film by means of FT-IR、TG-DTG、SEM、AFM、XPS. Finally studying the influence of the weathered coals’ s particle size and addition on water retention 、 thermal insulation and biodegradable properties. The research results shows:Uniform film formed between weathered coal system and PVA/CMS system. The optimum technological conditions of the preparation for mulch film: Na OH amount is 0.8 g、crosslinking time is 55 min、crosslinking temperature is 85 oC and cross-linking agent content is 1.5%. Under the optimum preparation conditions, the tensile strength is 9.7 MPa, the breaking elongation is 156.5%.The contrast of characterization results before and after the weathered coals added shows: the intermolecular hydrogen bond between PVA/CMS system and humic acid are formed, and the mechanical performance of mulch film were promoted; Remaining residue has filling effect in the film, can enhance the strength of the membrane, but impact breaking elongation. The more addition of pulverized weathered coals will result in uneven thickness and the mechanical properties of membrane will decline.With the increasing adding amount of weathered coals, the water retention and thermal insulation performance of membrane is getting better, While the biodegradability of the weathered coals-based film appears first quick back slow trend with the increase of the weathered coals addition, the degradation rate is fastest as the adding amount was 10%. As the pulverized weathered coals particle size turn bigger, the water retention of films first increase and then decrease, the thermal insulation performance decrease as the particle size increase. When the addition is 40% and the size is 325 mesh we will get the best thermal insulation performance. The smaller of the weathered coals size, the faster of the degradation rate. When the weathered coals size was 325 mush, the degradation is best.