Effect of clay type and loading on thermal,mechanical properties and biodegradation of poly(lactic acid) nanocomposites

PLA nanocomposites based on two different clays (CLO30B and SOMMEE) at 5 and 10 wt.% clay loading were prepared by melt-blending, obtaining a good level of clay dispersion as well as considerable thermo-mechanical improvements in PLA, according to WAXS, SEM, TEM, DMTA and tensile strength analysis.Addition of clays induced PLA crystallization by nucleation, especially upon addition of SOMMEE, promoting kinetics and extent of crystallization of the polymer, especially at high clay content. Concerning the thermal and mechanical properties, the highest improvements in PLA matrix were obtained upon 10% clay addition, especially SOMMEE, becoming more noticeable with increasing temperature.An effective degradation of PLA and nanocomposites in compost at 40 °C was also achieved. It was found that addition of nanoparticles, especially SOMMEE, accelerated the degradation process of PLA, particularly at higher clay content, probably due to catalysis by the hydroxyl groups belonging to the silicate layers surface and/or to their organic modifier.     

Assessment of the exposure to Allura Red colour from the consumption of red juice-based and red soft drinks in Italy

This article reports the results of a survey and an exposure study, based on a probabilistic approach, concerning red juice-based and red soft drink products in Italy. It highlights the fact that the estimates of both the consumption rates and colorant intakes are related to the hypotheses of scenarios. In fact, the study estimates that, on average, consumers of red soft drinks consume 53.1 L year(-1), ranging from 39.1 to 70.7 L of soft drink products under one scenario, or 21.3 L, and from 12.7 and 35.9 L under another hypothesis; while 9.5 L of red juice-based drinks are consumed per year, ranging from 7.0 to 12.5 L, under one scenario, or on average 6.9 L, and ranging from 3.2 to 17.7 L under another scenario. The amount of colorant in a red beverage ranged from 10.9 mg l(-1) in a red soft drink up to 55.9 mg l(-1) in a red juice-based product. The risk evaluation process showed that in all cases the intake of E129 was always lower than the acceptable daily intake. The exposure assessment showed high average intakes of Allura Red in the worst-case scenario, on average, 6.5 and 13.9 mg day(-1), up to 25.0 and 33.0 mg day(-1) at the 95th percentile, for juice-based and soft drinks respectively. The most realistic scenario estimated a weighted average daily intake of Allura Red, on average from about 0.3 to 0.5 mg day(-1) at the 95th percentile, and from 0.4 to 0.6 mg day(-1) for the 95th percentile, from juice-based and soft drinks, respectively. Actually, the highest colorant intake was estimated in a 'health' juice-based drink. The intake of E129 significantly increased with a high level of colorant (>40 mg l(-1)).