Films biodegradability testing

The biodegradation of Ecoflex film was tested under composting conditions. After 100 days in a composting environment more than 90% of the carbon in the polymer was converted to carbon dioxide. Tests also showed no toxic effects of degradation intermediates. 

Chiellini, E. Cinelli, P. Corti, A. Kenawy, E.R. Composite films based on waste gelatin Thermal-mechanical properties and biodegradation testing. Polym. Degrad. Stab. 2001, 73, 549 - 555. 

Test specimens of chitin and chitosan films were cut into 5 x 5 cm squares to evaluate their biodegradation properties. For the biodegradation test, they were buried in the soil (outdoors), 10 cm below the surface. Two kinds of soils, paddy soil and red clay, were chosen. The burying period of the test samples was 1,1.5, and 2 months. 

Chitosan is a water-insoluble, nontoxic, edible, biodegradable polymer (polysaccharide) that is obtained commercially from chitin by alkaline deacetylation [103]. Chitosan is the second most abundant biopolymer in nature after cellulose. Since chitosan is a polycationic polymer, its high sensitivity to moisture limits its applications. One way to overcome this drawback is to blend the material with humidity resistant polymers such has PLA. Suyatma et al. [104] combined hydrophilic chitosan with hydrophobic PLA (92% L-lactide and 8% mesolactide, Mw = 49,000 Da) by solution and film mixing, resulting in improved water barrier properties and decreased water sensitivity of the chitosan films. However, testing of mechanical and thermal properties revealed that chitosan and PLA blends are incompatible. 

Figure 2.2 Weight loss of various polyesters in different anaerobic environments after 14 weeks at 35 °C. (Polyester films diameter = 25 mm surface area 39.3 cm initial film weights = 39-49 mg 3 films per test.) Reproduced with permission from D.M. Abou-Zeid, Anaerobic Biodegradation of Natural and Synthetic Polyesters, Technical University Braunschweig, Braunschweig, Germany. 2000, Technical University Braunschweig...

For long term biodegradability tests, the films buried in soil cultivated with Vida X. Hybrida hort in greenhouse conditions changed their properties after a period of 7 months, these conditions being aggressive as laboratory-accelerated conditions due to the complex phenomena determined by the action of rhizo-spheres [81b]. 

Chiellini, E., Cinelli, P., Corti, A., and Kenawy, E.R., 2001, Composite Films Based on Waste Gelatin Thermal-Mechanical Properties and Biodegradation Testing. Polym. Degr. Stab. 73 549-555. 

Another impact on the environment is the possible production of micro fragments during the biodegradation process. To assess this micro fragment production, experiments conducted in laboratory conditions and real conditions have been set up (Charrier, 2003). Three films were tested (i) polyester aUph/ arom -l- starch, (ii) polyester aUph/arom -i- natural fibres and (iii) polyethylene + pro oxidant. The results are shown in Table 19.4. In test A, samples of films were ineorporated into pots containing a natural soil. These pots were put in an oven at 30 C for six months, and were regularly watered to ensure a constant soil humidity. A similar experiment, test B, was performed in compost... 

Manera C, Margiotta S, Di Muro E, Gatta G (2002) Experimental tests on innovative and biodegradable films for solarization soil in a site of south Italy. Acta Hort (ISHS) 578 363-371 Mansoori B, Jaliani NKH (1996) Control of soilborne pathogens of watermelon by solar heating. 

Russo G, Candura A, Scarascia-Mugnozza G (2005) Soil solarization with biodegradable plastic film two years of experimental tests. Acta Hort (ISHS) 691 717-724... 

PVA films buried in soil were tested after 120 days and showed only very limited signs of biodegradation, and even field tests with PVA sheets buried for 2 years in different natural soil sites showed only limited (10%) weight loss. No traces of colonising microorganisms were detected on the incubated material. Degradable polymers like poly(hydroxy butyrate), PCL or starch are usually extensively... 

In pursuit of a chlorine-resistant, non-biodegradable thin-film-composite membrane, Cadotte et al. 97 )03,104 fabricated interfacially the poly(piperazineamide) membrane (NS-300). The interfacially formed piperazine isophthalamide and terephthalamide membranes exhibited high salt rejection (98 %) in sea water tests but their flux was low (Table 8). The replacing of the isophthaloyl chloride with its triacyl chloride analog, trimesoyl chloride improved vastly the flux of the membrane but its seawater salt rejection was low — in the range of 60 70 % (55). The trimesoyl... 

The company is also in the process of developing a metallised NatureFlex film, which is currently undergoing independent testing in order to formally confirm its biodegradability and compostability. 

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