Investigations of Stresses in Glass Bottles Under Internal Hydrostatic Pressure

The behavior of glass bottles under internal hydrostatic pressure has been studied. Three commercial beer bottle designs were investigated by four different methods of experimental stress analysis, namely, photoelastic, electric strain gauge, brittle coating, and brittle model methods. The "fixation" or "stress-freezing" method of three-dimensional photoelastic stress analysis employing Fosterite models has been applied to the study of glass bottles apparently for the first time. By this method extensive measurements of the surface stress distributions have been made and are presented in graphical form. Other tests corroborate these results and illustrate the characteristics of bottles under internal pressure, including the effects of certain elements of bottle design. Results obtained by all four methods correlate well and should find valuable and practical applications in similar studies on other types of glass containers     

Improved method for detection of organotins in food simulants

An improved method for detection of organotin compounds in fatty food-simulants has been developed. It offers improved sensitivity and specificity over complexation-colorimetric and other methods. This method has been used to test for leaching of tin from PVC bottles stabilized with methyltin stabilizers. The results of this testing at various temperatures demonstrated safe levels for consumers.     

Transport in oriented bottles made from polyester resin

Oxygen permeation has been measured in flat sheet as a function of degree of orientation, and oxygen and water transport have been measured in oriented polyester bottles. O₂ permeability in flat sheets decreases gradually with orientation on either side of an abrupt decrease by about a factor of 2 after moderate orientation. The bottles tested were all more highly oriented than that critical decree; no significant effect of orientation on water or O₂ transport in bottles could be found. Only container intrinsic viscosity (IV) (which is determined by molecular weight, and is therefore a convenient measure of polymer degradation) was significantly related to the transport properties of the bottles. It was found that O₂ transport is increased with increasing IV while H₂O transport decreased. The explanation for these seemingly contradictory data can be found in the chemistry of degradation of the polyester.     

Prediction of the Bursting Pressure of Oriented Plastic Bottles

The introduction of biaxially oriented PET bottles to replace conventional glass bottles for packaging carbonated soft drinks has been a very successful commercial endeavor. The scientific approach to optimum design of thermoplastic bottles seems to lag behind technological developments. Very few scientific papers have been published on this subject.     

Vinyl bottle performance with the addition of vinyl bottle flake

The effect of adding recycled vinyl bottle flake to virgin bottle compound has been studied. Vinyl bottles contains 10 to 50% recycled vinyl bottle flake were produced on a Bekum extrusion blow molding machine. The performance properties of the vinyl bottles were evaluated, and the optimum level of recycled flake was determined.     

Effect of Resin Types and Antioxidants on Release of Off-Flavor From HDPE Bottles

The effects of three types of high-density polyethylene (HDPE) resins (A, B, and C) and three antioxidants (vitamin E, Irganox 1010, and BHT) on the release of off-flavor (including off-odor and off-taste) from blow-molded HDPE bottles were investigated using sensory analysis and gas chromatography/mass spectrometry (GC/MS) analysis. Overall the sensory study showed that off- flavor intensity was affected by both resin type and antioxidant. Resin A bottles yielded less off-flavor compared to resin B or C bottles. Vitamin E containing bottles yielded less off-flavor compared to Irganox 1010 or BHT containing bottles for resins A and B; however, the antioxidants have almost the same effect on resin C. The GC/MS study identified more than 60 volatile compounds released from the bottles, ranging from C₅ to C₂₀, which belonged to the groups of n-alkane, 1-alkene, aldehyde, ketone, phenolic, olefin, and paraffin—among them aldehydes and ketones were the most important due to their very low odor thresholds. Resin A bottles yielded less aldehyde and ketone compared to resin B or C bottles. Vitamin E containing bottles yielded less aldehydes and ketones compared to bottles containing Irganox 1010 or BHT. There was a general consistency between the sensory and GC/MS data. The aldehyde and ketone concentration was linearly correlated reasonably well to odor (R ² = 0.78) and taste scores (R ² = 0.67). Another study was also conducted, which shows vitamin E has smaller reduction in melt flow index due to blow molding compared to Irganox 1010 or BHT.     

DECREPITUDE OF OLD BOTTLES: AGING, WEATHERING, AND SOLARIZATION COMPARED WITH USE AND ABUSE*

The users of bottles often saythat old bottles are stronger than new nnes. This is untrue because (1) any greater breakage on the Grst filling can be attributed to abnormally weak bottles or bottles cracked during shipment; the survivors may give less breakage on the second and third fillings, but the strength of the individual bottle has not actually increased; and (2) the statement is based on the faulty assumption that bottles are not weakened by use. Experimental tests on fruit jars in the absence of use do not show a decrease in the thermal-shock strength after seven years of aging plus three years of weathering by temperature changes, rain, snow, and sunshine. Neither does weathering for three years nor solarization in the direct rays of the July and August sun produce any decrease in the internal pressure strength of bottles. Mechanical strength tests, fracture diagnoses, and statistical surveys of the performance of bottles in service, however, show that the strength of glass containers deteriorates because of mechanical wear, use, and abuse.     

STRESSES IN BOTTLES OR JARS FROM DIFFERENCES IN OUTSIDE AND INSIDE TEMPERATURES (STATIC TEMPERATURE GRADIENT)*

This investigation shows that there is likely to be a severe concentration of stress in bottles or jars on the outside face of the junction of side walls and base when the bottles are subjected to a thermal gradient, that is, hot inside and cold outside. The stress in this area apparently may be two or three times as high as the general average, and its amount depends on the details of design at this point. A general formula, intended as a first approximation to the stress, has been worked out. That this region is a region of weakness is not news, but the reasons for it, as deduced in this study, are different from those generally given. Murgatroyd has shown that scratches on a bottle have a greater influence here than elsewhere and that their vulnerability is greatest if they are horizontal. His results are empirical, and he does not explain them. The explanation is given here.     

Combustion‐thermal‐sprayed recycled poly(ethylene terephthalate)

Thermal‐sprayed polymer coatings have been used as protection against corrosion and wear. In this study, poly(ethylene terephthalate) (PET) powder, which was obtained from postconsumer beverage bottles, was deposited on 1020 steel by low‐velocity flame‐spray technology. The chemical and structural changes in PET due to the thermal‐spray processing were investigated with Fourier transform infrared spectroscopy and X‐ray diffraction. Changes in tribological behavior were examined by pin‐on‐disk testing and three‐dimensional profilometry. The results show that coatings had the same functional groups as the PET beverage bottles. However, the degree of crystallinity was modified. These changes were rationalized in terms of possible structural modifications of the PET polymer. The study showed evidence that the pin‐on‐disk wear developed by an abrasion process through a ploughing mechanism, although a fatigue mechanism could not be disregarded. A low friction coefficient between PET and steel was confirmed. In the as‐sprayed condition, the PET coatings showed higher friction, likely because of a higher coarse debris production rate during the pin‐on‐disk testing. Heat treating the as‐sprayed coating to increase the amorphous PET content improved the sliding behavior by increasing wear resistance. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3159–3166, 2004     

Energy absorption capability of recycled plastic bottles

The main objective of this study was to explore the potential effectiveness of using recycled plastic bottles as a material for roadside crash‐barriers. A test program was conducted to compile data on the energy‐absorbing potential of commonly available plastic bottles. The main and secondary factors in plastic bottle energy‐absorption were identified and orthogonal arrays were used to define the test matrix, thereby avoiding the full factorial number of experiments. The results of the study were energy‐absorption data for a range of commercially available plastic bottles. The data are for various filler materials and two loading directions on the bottles. Analysis‐of‐variance was used to identify the most significant factors in energy absorption. The main conclusion of the study was that commercially available plastic bottles, when filled with the appropriate filler materials, are capable of absorbing significant amounts of crush energy. The main recommendation was that the economic feasibility of recycled plastic bottles in various types of crash barriers be explored, including more efficient or more practical filler materials.     

The effects on the properties of PET bottles of changes to bottle‐base geometry

Poly(ethylene terephthalate) (PET) bottles are commonly used for packaging of carbonated beverages. Stress cracking in the petaloid‐shaped base of the filled bottle has been costly to the beverage industry. This study compares the performance of a standard bottle and a bottle with a base geometry optimized against environmental stress cracking (ESC). The crystallinity of the bottle base is evaluated across the base diameter for both bottles. Moreover, to explain the mechanism of the crack formation and propagation, the cracks in the bottle base are investigated through environmental scanning electron microscopy (ESEM) and optical microscopy. Top‐load strength, burst strength, and thermal stability are also reported. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Application of the Fluorescent Light Test and Some Other Methods for Determination of the Stability of Different Edible Oils

For the stability determination of different kinds of edible oils (sunflower, corn and soybean) various methods have been applied: Fluorescent light test, AOM-method, Oventest and Stability at room temperature. The fatty acid composition, the tocopherol content and the quality characteristics (peroxide value, anisidine value, content of dienes and trienes) were determined before testing of the stability. Special attention has been given to the determination of stability by the Fluorescent light test. This test seems to be very interesting in the determination of oil stability because the action of light is the main factor for the deterioration of the oil, while it is in the supermarkets in clear glass or plastic bottles (oil is not packed in brown glass in Yugoslavia). Oil in 1 liter original glass or plastic bottles or in 50 cm³ jars was exposed to the influence of the light of four 40 W fluorescent cool-white tubes of 1 m. Oxidation rate of the samples was followed by measuring the peroxide value. For the organoleptic evaluation, a three-member panel judged the flavor on a 10 point scale. The obtained results show that, under the conditions of this test, corn oil has the best stability. Sunflower oil has two and half time better stability than soybean oil. Some correlation has been established between the stability obtained by all applied methods.     

Characterisation of biaxial orientation gradients in poly(ethylene terephthalate) films and bottles using polarised attenuated total reflection FTIR spectroscopy

Polarised attenuated total reflection (ATR) infrared spectroscopy has been used to quantify biaxial orientation in commercially manufactured poly(ethylene terephthalate) (PET) films and stretch-blow moulded bottles. Using a single-bounce accessory with a high refractive index element, and applying appropriate data normalisation prior to measuring band intensities, measurement of the average square direction cosines that describe the orientation is simple. Using this technique it was shown that uniaxially drawn PET films were actually biaxially oriented, and there were significant gradients in orientation through the film thickness. Bulk measurements, or methods that assume uniaxial orientation, would give incorrect results from these materials. The bottles exhibited complex orientation patterns that depended on preform and mould design, and again there were strong orientation gradients through the bottle walls. Kratky's model (pseudo-affine) was used in an attempt to predict the biaxial orientation gradients as a function of preform and bottle dimensions.     

GLASS CONTAINERS1

For centuries glass bottles have been recognized as superior containers. At present over 4000 different sizes and shapes are being made and the industry is in a state of rapid extension. Glass containers possess the advantage of being sanitary and permitting the contents to be seen. Recently the laboratory of the Glass Container Association has tested 180 lots of beverage bottles. Some of the better types, or those approaching the champagne style, were found to withstand an end crushing pressure of from 8000 to 12000 pounds, a transverse pressure of from 800 to 1800 pounds, a hydrostatic pressure of from 400 to 1600 pounds, and an impact of a fifty-pound hammer falling from 2 to 6 feet. Similar tests are in progress on other types of containers and on the closures employed. Troubles due to alkalinity are of rare occurrence.     

Flavor and oxidative stability of hydrogenated and unhydrogenated soybean oils. Efficacy of plastic packaging

Soybean oils were packaged in polyvinylchloride, acrylonitrile, clear glass and amber glass bottles and their flavor stabilities were evaluated by a trained sensory panel. Hydrogenated and unhyrdogenated oils showed similar patterns of flavor deterioration regardless of container or type of aging. In accelerated light-exposure tests with air in the headspace, oils in plastic bottles showed flavor and oxidative stability equivalent to the same oils in clear glass bottles. Packaging in the amber glass bottle provided, as expected, significantly improved oil stability during light-exposure tests. In accelerated storage tests at 60 C with air in the headspace, sensory evaluation and peroxide determination showed no significant differences in oils packaged in clear glass and PVC, but sometimes oils received lower scores in glass compared with those in acrylonitrile bottles. During long-term storage, oils in plastic bottles with nitrogen in the headspace had flavor and oxidative stabilities equal to oils in glass bottles with nitrogen. These investigations indicate that packaging soybean oils in polyvinylchloride or acrylonitrile bottles is a viable alternative to packaging in clear glass bottles.     

Chemical,thermal, and mechanical properties and ultraviolet transmittance of novel nano-hydroxyapatite/polyethylene terephthalate milk bottles

Polyethylene terephthalate (PET)/nano-hydroxyapatite (nHAp) composite granules were obtained using twin-screw extruder. Preforms were prepared by injection molding and then PET/nHAp bottles were produced by blow molding. For PET bottles with nHAp, the migration amounts of carboxylic acid (COOH), acetaldehyde (AA), diethylene glycol (DEG), and isophthalic acid (IPA); glass transition temperature (T_g); melting temperature (T_m); and the maximum crystallization temperature (T_cry) were measured. The load-carrying capacity, burst strength, stress cracking, and regional material distribution tests were carried out on the bottles. X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, and ultraviolet transmittance analyses were conducted to explain the changes in mechanical, chemical, physical properties, and light transmission of bottles. It was found out that the COOH amount increased and the AA content decreased with increasing nHAp amount. On the other hand, no change was observed in the amounts of DEG and IPA. Although the mechanical properties such as load-carrying capacity and burst strength of the bottles have improved, it has been determined that the standard environmental stress crack resistance test procedure cannot be applied to such a composite. Experimental findings indicate that nHAp disrupts the chemical structure of PET and it isolates harmful chemicals such as AA by forming intermolecular bonds. Moreover, with the addition of up to 0.8% nHAp, PET bottles block the light transmission approximately 80% within 400–700 nm wave length zone. The study demonstrates that the PET/nHAp composite bottles can be used in the food industry, particularly in the packaging of milk and milk products which are vulnerable to light exposure.     

Oxygen permeation resistance of polyethylene,polyethylene/ethylene vinyl alcohol copolymer,polyethylene/modified ethylene vinyl alcohol copolymer,and polyethylene/modified polyamide–ethylene vinyl alcohol copolymer bottles

The oxygen permeation resistance of polyethylene (PE), polyethylene/ethylene vinyl alcohol copolymer (PE/EVOH), polyethylene/modified ethylene vinyl alcohol copolymer (PE/MEVOH), and polyethylene/modified polyamide–ethylene vinyl alcohol copolymer (PE/MPAEVOH) bottles was investigated. The oxygen permeation resistance improved significantly after the blending of ethylene vinyl alcohol copolymer (EVOH) barrier resins in PE matrices during blow molding; less demarcated EVOH laminas were found on the fracture surfaces of the PE/EVOH bottles. Surprisingly, the oxygen permeation resistance of the PE/MEVOH bottles decreased significantly, although more clearly defined modified ethylene vinyl alcohol copolymer (MEVOH) laminas were found for the PE/MEVOH bottles as the compatibilizer precursor contents present in the MEVOH resins increased. In contrast, after the blending of modified polyamide (MPA) in EVOH resins, more demarcated modified polyamide–ethylene vinyl alcohol copolymer (MPAEVOH) laminar structures were observed in the PE/MPAEVOH bottles as the MPA contents present in the MPAEVOH resins increased. In fact, with proper MPAEVOH compositions, the oxygen permeation resistance of the PE/MPAEVOH bottles was even better than that of the PE/EVOH bottles. These interesting oxygen barrier and morphological properties of the PE, PE/EVOH, PE/MEVOH, and PE/MPAEVOH bottles were investigated in terms of the free volumes, barrier properties, and molecular interactions in the amorphous‐phase structures of the barrier resins present in their corresponding bottles. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2528–2537, 2004     

21世纪包装及玻璃啤酒瓶的替代材料PET的市场前景

介绍了PET的性质、包装领域的应用，国内外市场动态，特别以PET－PEN瓶替代玻璃啤酒瓶的广阔市场前景和综合回收利用方面的新进展作了概述。     

Molecular morphology of petaloid bases of PET bottles: A small‐angle X‐ray scattering study

Small‐angle X‐ray scattering (SAXS) studies were undertaken to explore possible morphological explanations for poor mechanical strength in the petaloid bases of poly(ethylene terephthalate) (PET) bottles. The bottles were manufactured using a two‐stage injection stretch blow molding process. Splitting of PET bottle bases under load is both inconvenient and expensive. In this study, SAXS data were collected with a 100 μm square X‐ray beam to establish the molecular morphology as a function of position across the base topology. An amorphous region was identified in the base center (i.e., close to the injection gate of the preform) with biaxially orientated, semicrystalline regions in the feet and valleys of the bottle bases. For bottles that had split under load, the transition between these two regions displayed uniaxial orientation that would lead to reduced mechanical strength in the circumferential direction. Reasons for this effect are explored. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3328–3335, 2006     

Gasoline permeation resistance of the as‐blow‐molded and annealed polyethylene,polyethylene/polyamide,and polyethylene/modified polyamide bottles

An investigation of the gasoline permeation resistance of the as‐blow‐molded and annealed polyethylene, polyethylene (PE)/polyamide (PA), and polyethylene/modified polyamide (MPA) bottles is reported. The gasoline permeation resistance improves dramatically after blending PA and MPA barrier resins in PE matrices during blow‐molding, and the order of barrier improvement corresponds to the order of barrier improvement of the barrier resins added in PE. Somewhat unexpectedly, the gasoline permeation rates of the annealed PE and/or PE/PA bottles annealed at 90°C or higher temperatures increase significantly with the annealing temperature and time. On the contrary, the gasoline permeation resistance of the annealed PE/MPA bottles increase significantly as the annealing temperature and/or time increase. For instance, the gasoline permeation rate of the PE/MPA bottle annealed at 120°C for 32 h is about 190 times slower than that of the as‐blow‐molded PE bottle. Further investigations found that, after blending the MPA and PA barrier resins in PE matrices, the relatively nonpolar hydrocarbon components present in the gasoline fuels were significantly blocked, without permeation during the permeation tests, in which the as‐blow‐molded PE/MPA bottle inhibited the permeation of hydrocarbon components more successfully than did the as‐blow‐molded PE/PA bottle. In contrast, the amounts of polar components that permeated through the as‐blow‐molded PE/PA and PE/MPA bottles were very small and about the same as the amount that permeated through the as‐blow‐molded PE bottle. Possible mechanisms accounting for these interesting behaviors are proposed in this study. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2827–2837, 2001