scholarly journals Opening up ZSM-5 Hierarchical Zeolite’s Porosity through Sequential Treatments for Improved Low-Density Polyethylene Cracking

Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2878 ◽  
Author(s):  
Karolina A. Tarach ◽  
Kamila Pyra ◽  
Kinga Góra-Marek
Keyword(s):  
Catalytic Cracking ◽  
Product Distribution ◽  
Acid Sites ◽  
Limiting Factors ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Ft Ir ◽  
Sequential Treatments ◽  
Opening Up

An adequately tuned acid wash of hierarchical ZSM-5 zeolites offers a levelling up in the catalytic cracking of low-density polyethylene. Identification of crucial and limiting factors governing the activity of the zeolite was extended with studies about the accessibility of acid sites, nature of the realuminated layer and role of Lewis acid sites. The sequential treatment of a ZSM-5 zeolite offered enhanced activity in low-density polyethylene (LDPE) cracking at low and high conversions, as confirmed by a decrease in the temperatures needed to reach 20% and 80% conversion (T20 and T80, respectively). A linear dependence of the T80 on the coupled IHF (indexed hierarchy factor) and AFB (accessibility factor) highlighted the importance of the textural and acidic parameters in the catalytic cracking of LDPE. Operando FT-IR-GC studies confirmed a higher fraction of short-chain hydrocarbons (C3–C5) in the product distribution of hierarchical catalysts resulting from the effective polymer cracking in easily accessible pores.

scholarly journals Polyethylene Migration from Food Packaging on Cheese Detected by Raman and Infrared (ATR/FT-IR) Spectroscopy

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3872
Author(s):  
Klytaimnistra Katsara ◽  
George Kenanakis ◽  
Zacharias Viskadourakis ◽  
Vassilis M. Papadakis
Keyword(s):  
Vibrational Spectroscopy ◽  
Food Packaging ◽  
Time Frame ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Ft Ir ◽  
Comparative Results ◽  
Short Time ◽  
And Storage ◽  
Ft Ir Spectroscopy

For multiple years, food packaging migration has been a major concern in food and health sciences. Plastics, such as polyethylene, are continuously utilized in food packaging for preservation and easy handling purposes during transportation and storage. In this work, three types of cheese, Edam, Kefalotyri and Parmesan, of different hardness were studied under two complementary vibrational spectroscopy methods, ATR-FTIR and Raman spectroscopy, to determine the migration of low-density polyethylene from plastic packaging to the surface of cheese samples. The experimental duration of this study was set to 28 days due to the degradation time of the selected cheese samples, which is clearly visible after 1 month in refrigerated conditions at 4 °C. Raman and ATR-FTIR measurements were performed at a 4–3–4–3 day pattern to obtain comparative results. Initially, consistency/repeatability measurement tests were performed on Day0 for each sample of all cheese specimens to understand if there is any overlap between the characteristic Raman and ATR-FTIR peaks of the cheese with the ones from the low-density polyethylene package. We provide evidence that on Day14, peaks of low-density polyethylene appeared due to polymeric migration in all three cheese types we tested. In all cheese samples, microbial outgrowth started to develop after Day21, as observed visually and under the bright-field microscope, causing peak reverse. Food packaging migration was validated using two different approaches of vibrational spectroscopy (Raman and FT-IR), revealing that cheese needs to be consumed within a short time frame in refrigerated conditions at 4 °C.

Effect of UV Treatment on Optical Properties of Low-Density Polyethylene Films Doped with Eu(TTA)3phen Complex

2014 ◽  
Vol 895 ◽  
pp. 155-161
Author(s):  
M.I. Khairuldin ◽  
N.M.A. Aziz ◽  
N.M. Nashaain ◽  
S. Wedianti ◽  
I. Farehah ◽  
...  
Keyword(s):  
Optical Properties ◽  
Emission Spectra ◽  
Low Density Polyethylene ◽  
Rare Earth Complex ◽  
Low Density ◽  
Uv Treatment ◽  
Uv Spectrum ◽  
Light Manipulation ◽  
Emission Transition ◽  
Ft Ir

Low-Density Polyethylene (LDPE) films doped with Eu (TTA)3phen complex (TTA=2-thenoyltrifluoroacetone, phen=1,10-phenanthroline) were fabricated by hot-blowing technique for thickness of 100 μm. The films were doped with 0.1 % of Eu (TTA)3phen to the total weight of LDPE and exposed to UV irradiation from deuterium lamp for 5, 10, 20, 40 and 60 hours to investigate the effect of its optical properties. The films were characterized by Spectrofluorometer, UV/VIS Spectrophotometer and FT-IR Spectrometer to measure their emission spectra, lifetimes, transmission transparency and chemical bonding. Photoluminescence of the room-temperature Eu (TTA)3phen doped films consist of typical Eu3+emission transition lines with hypersensitive5D07F2emission band at 610 nm. After 20 hours UV treatment, the peak intensity dropped by 90 % and shortened the luminescent lifetimes from 0.654 ms to 0.305 ms. Longer UV treatment also has accelerated degradation in doped LDPE films shown by significant reducing in absorption peak of FTIR at 3395, 3186 and 1645 cm-1. The results would provide a mechanism to improve the lifetime of the LDPE by utilizing the light-manipulation property of Eu (TTA)3phen complex to absorb UV spectrum and covert into red emission.Keywords: LDPE, rare-earth complex, photoluminescence

scholarly journals Vida útil de polpa congelada de araticum embalada ou não a vácuo

2019 ◽  
Vol 6 (1) ◽  
pp. 114-121
Author(s):  
Cristiane Maria Ascari Morgado ◽  
Ana Paula Silva Siqueira ◽  
Eli Regina Barboza de Souza ◽  
Annelisa Arruda de Brito ◽  
Luis Carlos Cunha Junior ◽  
...  
Keyword(s):  
Titratable Acidity ◽  
Soluble Solids ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Antioxidant Power ◽  
Total Antioxidant ◽  
Ferric Reducing Antioxidant Power ◽  
Annona Crassiflora

The objective of this work was to evaluate the role of two types of conditioning process in quality of frozen and stored araticum’s pulp at -18ºC. The fruits were collected at pre-maturing developmental stage, packed into boxes wrapped with bubble plastic, transported to the laboratory and stored for 7 days at 22ºC and 90% RH to complete the maturation. Afterwards, they were pulped and the pulp was stored in: 1) low-density polyethylene packages (LDPE) 60 micro, hermetically packed in a sealing machine or 2) low-density polyethylene packages (LDPE) 60 micro vacuum sealed. Those units were frozen at -18ºC for 402 days and were evaluated at processing day and at 30; 90; 150; 210 and 402 days of storage, for soluble solids contents (SS), titratable acidity (TA), SS/TA, ascorbic acid, total extractable polyphenols and total antioxidant activity using the Ferric Reducing Antioxidant Power (FRAP) method. The results were submitted to an analysis of variance and the means were each other compared using Tukey test with Sisvar software. It is conclued that is not necessary the use of vacuum to package the frozen araticum’s pulp for 402 days, at -18ºC. Keywords: Annona crassiflora Mart, freezing, vacuum.  

Tertiary Recycling of Low-Density Polyethylene by Catalytic Cracking over ZSM-11 and BETA Zeolites Modified with Zn2+: Stability Study

2013 ◽  
Vol 27 (4) ◽  
pp. 2202-2208 ◽  
Author(s):  
Laura C. Lerici ◽  
María S. Renzini ◽  
Ulises Sedran ◽  
Liliana B. Pierella
Keyword(s):  
Catalytic Cracking ◽  
Stability Study ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Beta Zeolites

On the durability of low-density polyethylene nanocomposites

e-Polymers ◽  
2004 ◽  
Vol 4 (1) ◽  
Author(s):  
Jitendra K. Pandey ◽  
Raj Pal Singh
Keyword(s):  
Ir Spectroscopy ◽  
Morphological Changes ◽  
Diffusion Path ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Neat Polymer ◽  
The Matrix ◽  
Ft Ir ◽  
The Stability ◽  
Artificial Uv

Abstract Low-density polyethylene (PE) containing nano-particulate clay was prepared after functionalization with maleic anhydride (MA) by reactive grafting in the presence of peroxide followed by blending of maleated PE with neat polymer in different concentrations. Four classes of composites were obtained: (i) exfoliated, (ii) intercalated, (iii) microcomposites, and (iv) intermediate of intercalated and microcomposites, as evidenced by wide-angle X-ray diffraction. All samples were kept for artificial UV irradiation (λ ≥ 290 nm) and for composting to study their photo- and bio-durability. Fourier-transform IR spectroscopy (FT-IR) and scanning electron microscopy were used to monitor the functional group and morphological changes, respectively, whereas biodurability was evaluated by measuring the weight loss. MA functionalization and nature of composites have detrimental effects on the overall durability of composites. Nanocomposites showed higher resistance than microcomposites during initial weathering and composting with a long induction period. The stability of nanocomposites decreases with time and overall durability was worse than of pristine polymer in both environments. It was concluded that the initial protection is due to the filler-generated long diffusion path, which decreases the oxygen diffusion through the matrix. The bio-durability of composites decreased with oxo-degradation. Biodegradation of PE nanocomposites during composting follows the mechanism described by Albertsson et al. as evidenced by FT-IR spectroscopy.

Sign in / Sign up

Export Citation Format

Share Document