High-Barrier Poly(hydroxy amide ethers):  Effect of Polymer Structure on Oxygen Transmission Rates. 31

1998 ◽  
Vol 31 (23) ◽  
pp. 8281-8290 ◽  
Author(s):  
David J. Brennan ◽  
Jerry E. White ◽  
Charles N. Brown
Keyword(s):  
Polymer Structure ◽  
Transmission Rates ◽  
Oxygen Transmission

High-Barrier Poly(hydroxy amide ethers):  Effect of Polymer Structure on Oxygen Transmission Rates. 21

1998 ◽  
Vol 31 (8) ◽  
pp. 2622-2630 ◽  
Author(s):  
David J. Brennan ◽  
Anthony P. Haag ◽  
Jerry E. White ◽  
Charles N. Brown
Keyword(s):  
Polymer Structure ◽  
Transmission Rates ◽  
Oxygen Transmission

Nd:YAG Laser Perforation of Plastic Films for Enhanced Breathability

2010 ◽  
Vol 93-94 ◽  
pp. 79-82 ◽  
Author(s):  
Charinee Winotapun ◽  
Noppadon Kerddonfag ◽  
Wannee Chinsirikul
Keyword(s):  
Nd:Yag Laser ◽  
Plastic Films ◽  
Transmission Rates ◽  
Biaxially Oriented Polypropylene ◽  
Laser Perforation ◽  
Oriented Polypropylene ◽  
Pulse Energies ◽  
Very High ◽  
Oriented Polyethylene ◽  
Oxygen Transmission

This study focused on investigating the Nd:YAG laser perforation process of several common plastic films including biaxially-oriented polypropylene (BOPP), biaxially-oriented polyethylene terephthalate (BOPET) and low density polyethylene (LDPE) films. Films were perforated under various pulse energies of 50, 150 and 250 mJ and with pulse duration of ~10 ns and pulse repetition of 1 Hz. It was found that, BOPP, BOPET and LDPE films could be perforated using our developed Nd:YAG laser perforating system. Perforation width or diameters of all films increased with increasing pulse energies. Observed perforations were different among the three film types. For instance, at the pulse energy of 150 mJ, average microperforation diameters of BOPP, BOPET, and LDPE were 51.9, 57.5, and 31.0 microns, respectively. Overall results clearly demonstrated that a Nd:YAG laser perforation process used in this study was effective in developing breathable packaging films with tailored oxygen permeation property. Commercial BOPP films containing 200-1,400 micro-perforations/m2 (average perforation diameter of  50 µm) showed a significant improvement in oxygen transmission rates (OTR) of 25-700% over that of the regular BOPP. Very high OTR films of 16,000 cc/m2.day could be effectively produced for the micro-perforated BOPP, where OTR values of close to 20,000 cc/m2.day was obtainable in the case of BOPET films.

Effect of Various Types of Vacuum Packages and Length of Storage on the Microbial Flora of Wholesale and Retail Cuts of Beef

1976 ◽  
Vol 39 (11) ◽  
pp. 745-753 ◽  
Author(s):  
S. C. SEIDEMAN ◽  
C. VANDERZANT ◽  
M. O. HANNA ◽  
Z. L. CARPENTER ◽  
G. C. SMITH
Keyword(s):  
Microbial Population ◽  
Microbial Flora ◽  
Transmission Rates ◽  
Coryneform Bacteria ◽  
Acinetobacter Spp ◽  
Retail Cuts ◽  
Retail Conditions ◽  
Lactobacillus Spp ◽  
Oxygen Transmission

Wholesale cuts of beef (knuckles, ribs, chucks) were vacuum packaged in three types of packages with oxygen transmission rates (cc/100 in.2/24 h) of 0.41–0.75, 1.09, and 2.28. One type of package was sealed with a clip; the others were heat sealed. Wholesale cuts were stored for 0–35 days at 1–3 C and retail cuts from ribs and knuckles were observed under retail conditions for 5 days. Differences in psychrotrophic, mesophilic, and lactobacillus counts of knuckles and ribs resulting from differences in type of package usually were not statistically significant. Differences in psychrotrophic counts of retail steaks of knuckles and ribs resulting from differences in type of package used for the primal cuts were not significant. Psychrotrophic and mesophilic counts of cuts in defective packages (leakers) increased faster than those of cuts in intact packages. The initial microbial flora of knuckles, ribs, and chucks consisted primarily of Moraxella-Acinetobacter spp. and coryneform bacteria. During the first few weeks of storage at 1–3 C Lactobacillus spp. already were dominant on knuckles and Microbacterium and Lactobacillus spp. predominated on ribs. After 28–35 days of storage Lactobacillus spp. were dominant on both knuckles and ribs. The microbial population on chucks after 21 days of storage consisted of Lactobacillus, Microbacterium, Enterobacteriaceae. Pseudomonas, Moraxella-Acinetobacter spp. and coryneform bacteria. The microflora of cuts from defective packages was comprised of species of Pseudomonas, Microbacterium, Lactobacillus, and Moraxella-Acinetobacter.

Microbial Flora of Vacuum-Packaged Lamb with Special Reference to Psychrotrophic, Gram-Positive, Catalase-Positive Pleomorphic Rods

1977 ◽  
Vol 40 (2) ◽  
pp. 98-100 ◽  
Author(s):  
M. O. HANNA ◽  
C. VANDERZANT ◽  
Z. L. CARPENTER ◽  
G. C. SMITH
Keyword(s):  
Special Reference ◽  
Polyvinyl Chloride ◽  
Microbial Flora ◽  
Refrigerated Storage ◽  
Gram Positive ◽  
Transmission Rates ◽  
Corynebacterium Species ◽  
Pvc Film ◽  
Corynebacterium Sp ◽  
Oxygen Transmission

Wholesale cuts of lamb (loins, legs) were packaged in polyvinyl chloride (PVC) film and in two other types of packages with oxygen transmission rates (cc/100 in2/24 h) of 0.41–0.75 and 2.28 respectively, Psychrotrophic counts were low (2 × 10-1.1 × 103 per in2) intially and after storage for 21 days increased to 103-1.6 × 105 per in2) Initially Corynebacterium species and Microbacterium thermosphactum were dominant. Upon refrigerated storage for 21 days, Lactobacillus, Pseudomonas, and Moraxella-Acinetobacter sp. became more significant. Among the Corynebacterium sp., buff-colored isolates, consisting of long, gram-positive pleomorphic rods in palisades were dominant.

scholarly journals Equibiaxially stretchable colorless and transparent polyimides for flexible display substrates

2020 ◽  
Vol 59 (1) ◽  
pp. 1-9
Author(s):  
Jin-Hae Chang
Keyword(s):  
Amic Acid ◽  
Thermal Cyclization ◽  
Flexible Display ◽  
Transmission Rates ◽  
Biaxial Stretching ◽  
Dimethyl Acetamide ◽  
Phenyl Sulfone ◽  
Yellow Index ◽  
Stretching Ratio ◽  
Oxygen Transmission

Abstract4,4′-(4,4′-isopropylidenediphenoxy)bis(phthalic anhydride) (BPADA) was reacted with three structurally different diamines to produce poly(amic acid)s, which were then imidized to produce colorless and transparent polyimide (CPI) films through stepwise thermal cyclization. The three amines used to synthesize CPI based on BPADA are: bis(3-aminophenyl)sulfone (APS), p-xylyenediamine (p-XDA), and bis[4-(3-aminophenoxy)-phenyl] sulfone (m-BAPS). The obtained CPI films were almost colorless and exhibited excellent optical transparencies. The solubility of the CPI films in various solvents was investigated, and all the CPI films were found to be soluble in common solvents such as chloroform, dichloromethane, N,N’-dimethyl acetamide, and pyridine. The thermo-optical properties and oxygen transmission rates (O2TRs) of the CPI films were examined for various biaxial stretching ratios in the range of 100–150%, and their properties were compared. When the stretching ratio changed from 100 to 150%, the glass transition temperature and yellow index did not show any significant change; however, the O2TR decreased for all CPI films.

Effect of High-Barrier Packaging Films with Different Oxygen Transmission Rates on the Growth of Lactobacillus sp. on Meat Fillets

2006 ◽  
Vol 69 (4) ◽  
pp. 943-947 ◽  
Author(s):  
E. TSIGARIDA ◽  
G.-J. E. NYCHAS
Keyword(s):  
Growth Rate ◽  
Transmission Rate ◽  
Packaging Film ◽  
Packaging Films ◽  
Transmission Rates ◽  
Oxygen Transmission Rate ◽  
Microbial Association ◽  
Final Population ◽  
Equal Importance ◽  
Oxygen Transmission

The goal of this study was to determine the combined effect of (i) the oxygen transmission rate (OTR) of packaging film, often called oxygen film permeability or film permeability and (ii) temperature on the growth rate of the main prevailing organism, Lactobacillus sp., in 100% CO2-packed sterile meat fillets. Multifactorial experiments were designed to study the effect of OTR and temperature (0, 5, 8, and 10°C) on the growth rate of Lactobacillus sp. inoculated on sterile meat fillets under 100% CO2 and aerobic conditions. The packaging conditions (air or 100% CO2) and the film OTR significantly affected the growth rate of Lactobacillus sp. only at temperatures higher than 0°C. Low-permeable films with different OTRs did not affect the final population of the bacterium, but the growth rate was significantly changed. The correlation of an ephemeral microbial association with a low spoilage potential (e.g., lactic acid bacteria) or their growth retardation cannot always be assumed unless other determinants (e.g., OTR) of equal importance are taken into account. The present study provides information that can be of benefit to industry and the consumer.

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