Study On The Preparation And Application Of Biodegradable Additives Applied In Polyethylene Film

Different photosensitizers which were added to the polyethylene film and then the effects of photo degradable and the biodegradable performance of the LLDPE film were studied in my dissertation. After testing, the best effective photosensitizer and the microorganism were obtained finally.The stearate iron FeSt₃ and the FeDBC were synthesized firstly, and then the ferrocene ((C₅H₅)₂Fe) was taken as the reference sample of the photosensitizer. The photo degradable performance of the LLDPE film was tested by the sunshine experiment in this dissertation. Three kinds of photosensitizers with LLDPE were mixed in the banbury mixer separately, then the LLDPE film blown by the plastic film blowing machine, and then the performance of specimen was tested. Taken 24 hours as a time cycle, the specimen were tested by the Ultraviolet ray illumination. The characteristic viscosimetry was tested to get the polymer molecular weight and the Carbonyl Index was got by Fourier infrared spectrumer.After carried on illumination 120h, the typical carbonyl was found at the place of 1715cm"1 in the infra-red spectrum curve. The service life of the LLDPE film is related to the contents of photosensitizers and illumination time, so the film service life can be controled by the content of photosensitizers. After photo-degraded 120h, the mechanical performance of specimen with FeSt3 (0.4%) decreasd to be a very low level, the film is not able to use. The molecular weight droped to 5000, so that the microorganism can eat the film as the carbon source. According to the results of Carbonyl Index, mechenical performance and the molecular weight of the film, we can get the following result: the effect of photo sensitive FeSt₃ is the best, followed by FeDBC, and the (C₅H₅)₂Fe is the worst.Therefore stearate iron (FeSt₃) was choosen as the photosensitizers to blow photo/biodegradation film, and the biodegradation property was tested and analysed further. The photo/biodegradation film is degraded after the ultraviolet ray or the sunshine illumination. The long chains of the polymer break down to the short chains, the carbonyl number increas and the polymer molecular weight decrease too. So the film can be degraded by the microorganism. And after selected, we finally discovered the microorganism Aspergillus Niger biodegrading this film from lots of strains.