Cioica N.,National Institute of Research Development for Machines and Installations designed to Agriculture and Food Industry Bucharest |
Fechete R.,Technical University of Cluj Napoca |
Chelcea R.,Technical University of Cluj Napoca |
Cota C.,National Institute of Research Development for Machines and Installations designed to Agriculture and Food Industry Bucharest |
And 4 more authors.
Studia Universitatis Babes-Bolyai Chemia | Year: 2015
The starch in native forms or chemically modified is found as the main component of biodegradable packaging materials. Regarding this the water can produce a fast degradation, of the order of days, of such materials. Four types of packaging materials, one witness and three with different starch, glycerol and water ratios were subjected to natural degradation after absorption of distilled water. The degradation process was monitored by various NMR relaxometry methods based on the measurement of CPMG (Carr-Purcell- Meiboom-Gill) decays with a T1 filter to exclude the signal from free water. The analysis of NMR signal decays was performed using a Laplace inversion algorithm and the dynamic components were identified from the T2 transverse relaxation times distributions. We found that the best package with 68/17/15 ratios between starch/glycerol/water is extremely degraded after just one day forming a colloid substance. After that in time we observe a quasi-solid precipitation at the bottom of NMR tube. The reduction of dynamics is observed also in the T2–distributions measured for 5 days. The most resistant package (78/19.5/2.5) was that with a large content of starch but which was also reaching the swallow limit in five days and start to be decomposed. © 2015, Universitatea Babes-Bolyai, Catedra de Filosofie Sistematica. All rights reserved.