Diffusion behaviour of additives in polypropylene in correlation with polymer properties

Begley, Timothy H.; Brandsch, Johannes; Limm, William; Siebert, Hartmut; Piringer, O.

doi:10.1080/02652030802162747

Cited by 20 publications

(14 citation statements)

References 12 publications

(2 reference statements)

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“…The Brandsch model in most cases leads to an overestimation because it offers the safety margin required by the consumer protection laws. The diffusion coefficient of limonene in PP‐H at 313K is 3.39 × 10 −9 cm 2 /s, which is consistent with the experimental value of 2.1 × 10 −9 cm 2 /s in the literature …”

Section: Results Discussionsupporting

confidence: 91%

Investigation in Influence of Types of Polypropylene Material on Diffusion by Using Molecular Dynamics Simulation

Wang

2011

Packag Technol Sci

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Polypropylene (PP) and its copolymers are widely used in food packaging films and containers. This paper investigates the diffusion of limonene as a low molar mass compound through three types of polypropylene materials (PP‐H, PP‐B and PP‐R) by using the molecular dynamics method, evaluates the influence of types of polypropylene material on the diffusion behaviour of limonene and reveals the diffusion mechanism. The diffusion coefficients of limonene in PP‐H, PP‐B and PP‐R are obtained at 313K and 353K. The accessible free volumes for polymers PP‐H, PP‐B and PP‐R are calculated by using the probe radius rp = 0.09, 0.11, 0.128 and 0.209 nm, respectively. The results suggest that not only the amount of accessible free volume in PP‐R cell model is larger than that of PP‐H and PP‐B but also the free volume in PP‐R connects together to form some larger free volume clusters. The movements of the limonene molecules through the PP‐H, PP‐B and PP‐R cell models at different simulation time suggest that for a long time the limonene molecules squirm slowly in the polymer cell rather than jumping and that the hopping diffusion is not suitable to explain the diffusion of limonene in polypropylene. The movement trajectories of the limonene molecules in PP‐R indicate that the movements of limonene in PP‐R are more active than that in PP‐H and PP‐B. The paper reveals the diffusion dynamics process and microscopic mechanism of small molecules from different types of polypropylene. Copyright © 2011 John Wiley & Sons, Ltd.

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Section: Results Discussionsupporting

confidence: 91%

Investigation in Influence of Types of Polypropylene Material on Diffusion by Using Molecular Dynamics Simulation

Wang

2011

Packag Technol Sci

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“…However, they reached the opposite conclusion-that the internal resistance is dominant while the external resistance is negligible. We think their argument is compromised by the unreasonably small value that they obtained (by fitting) for the intraparticle diffusion coefficient (D sp (Begley et al 2008), polyethylene (PE) terephthalate (Begley et al 2005), PVC (Messadi et al 1981), and PE (Lohmann 2012) are larger than 10 −14 m 2 /s, a diffusion coefficient smaller than 10 −18 m 2 /s seems unlikely.…”

Section: The Dynamics Of Gas/particle Interactions: Practical Implicamentioning

confidence: 93%

Analysis of the Dynamic Interaction Between SVOCs and Airborne Particles

Liu

Shi

Weschler

et al. 2013

Aerosol Science and Technology

137

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A proper quantitative understanding of the dynamic interaction between gas-phase semivolatile organic compounds (SVOCs) and airborne particles is important for human exposure assessment and risk evaluation. Questions regarding how to properly address gas/particle interactions have introduced uncertainty when predicting SVOC concentrations and assessing exposures to these compounds. In this study, we have developed a dimensionless description for the dynamic interaction between SVOCs and organic particles. A better criterion to judge whether the internal resistance (diffusion in and out of aerosols) is negligible compared with the external one (from bulk air to aerosol surfaces) is presented. The analysis is applicable regardless of the phase state of particles (either liquid or amorphous semisolid/solid). It is found that for both porous and nonporous particles, the internal resistance can be reasonably neglected for particles with diameters between 0.01 and 10 µm if the particulate organic matter is in the liquid phase. A lumped description therefore can be applied to determine, with greater accuracy than in previous studies, the timescale required to attain gas/particle equilibrium for such particles. The instantaneous equilibrium assumption is found to be reasonable for relatively volatile species such as pyrene, but not for the less volatile species such as di-(2-ethylhexyl)-phthalate (DEHP). For DEHP and 2.5 µm diameter particles, the instantaneous gas/particle equilibrium assumption can cause a two orders of magnitude error in the estimation of the gas-phase concentration and a factor of two error in the estimation of the particle-phase concentration.

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“…Many additives, such as antioxidants and UV protectants, act as sacrificial defenders that become chemically altered and/or degraded during polymer heating and processing and also over time as the plastic ages (6,7,15,16). The large size heterogeneity of the materials diffusing from the plastic microtubes suggests that leachates are composed of multiple additives and their breakdown products.…”

Section: Resultsmentioning

confidence: 99%

Interference with Spectrophotometric Analysis of Nucleic Acids and Proteins by Leaching of Chemicals from Plastic Tubes

et al. 2010

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Absorbance spectroscopy is routinely used to monitor the concentrations of nucleic acids and proteins within solutions and to assess changes in their structure caused by interaction with chemicals or other biomolecules. Biological samples used for such analyses are manipulated and stored in small microcentrifuge tubes (microtubes) composed of polypropylene plus several plastic additives. Here we demonstrate that normal handling of laboratory microtubes causes leaching of light-absorbing chemicals into biological samples that interfere with spectrophotometric measurements. The leached chromophores absorbed UV light strongly at 220 and 260 nm, which are the wavelengths normally used to detect and quantitate proteins and DNA. Some common laboratory techniques, including sonication and PCR, were particularly effective inducers of leaching. The magnitude of the increase in absorbance was dependent upon both exposure time and heat history, with greatest induction after tubes were warmed to temperatures at or above 37 degrees C. Mass spectrometry revealed that aqueous solutions stored in plastic microtubes accumulate a complex mixture of leached chemicals with molecular masses of 200-1400 Da. Leaching was ubiquitous among commercially available brands of microtubes, indicating a persistent source of error in biomolecule detection and concentration measurements.

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Diffusion behaviour of additives in polypropylene in correlation with polymer properties

Cited by 20 publications

References 12 publications

Investigation in Influence of Types of Polypropylene Material on Diffusion by Using Molecular Dynamics Simulation

Investigation in Influence of Types of Polypropylene Material on Diffusion by Using Molecular Dynamics Simulation

Analysis of the Dynamic Interaction Between SVOCs and Airborne Particles

Interference with Spectrophotometric Analysis of Nucleic Acids and Proteins by Leaching of Chemicals from Plastic Tubes

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