Effects of low density polyethylene liners and high-density polyethylene wraps on quality, decay and storage life of lemon and tangor fruits

1985 ◽  
Vol 25 (3) ◽  
pp. 718 ◽  
Author(s):  
PJ Sharkey ◽  
CR Little ◽  
IR Thornton

Winter-maturing Lisbon lemons (Citrus limon (L.) Burm.f.) and Ellendale tangors (Citrus reticulata x Citrus sinensis (L.) Osbeck) which had been dipped in fungicides and waxed, developed less than 10% rot but remained fresh for only 2-3 months in cool-storage at 10�C and 80-90% RH. High-density polyethylene (HDPE) wraps delayed loss of firmness and peel coloration of tangors and lemons for 5 and 8 months respectively, in cool-storage, but both citrus developed unacceptable levels of rotting within 4 months of harvest. Perforated low-density polyethylene liners were less effective than HDPE wraps for preserving fruit condition but they extended the storage life of lemons until early January (6 months) without incurring levels of decay greater than 10%. However, tangors cool-stored in liners became unsaleable after only 3-4 months owing to loss of acidity and flavour.

Author(s):  
S. JIPA ◽  
R. SETNESCU ◽  
T. SETNESCU ◽  
C. PODINA ◽  
J. MIHALCEA

The effectiveness of different phenolic antioxidants on high-density polyethylene (HDPE) and low-density polyethylene (LDPE) has been studied by the Isothermal chemiluminescence method. The decreasing order of the antioxidant efficiency for these polymers Is as follows: lrganox 1010 >> Etanox 330 > lrganox 1076 (Hostanox 016) > Topanol OC


2020 ◽  
Vol 10 ◽  
pp. 48-55
Author(s):  
H. V. Allakhverdiyeva ◽  
◽  
N. T. Kakhramanov ◽  
I. I. Ismayilov ◽  
◽  
...  

The paper presents the results of a study of the effect of aluminum content on the physic-mechanical properties of composites based on high density polyethylene and low density polyethylene. The properties of metal-filled composites, such as ultimate tensile stress, elongation at break, elastic module, melt flow rate, and heat resistance, were studied. According to the data obtained, the loading of aluminum into the composition of low density polyethylene contributes to a monotonic increase in the ultimate tensile stress and the elastic module. When aluminum is loading into the composition of high density polyethylene, on the contrary, a natural decrease in the ultimate tensile stress and elongation at break of the composites is observed. It is shown that when using a compatibilizer, which is polyethylene modified with maleic anhydride, a significant increase in the ultimate tensile stress of high-density polyethylene composites is observed. A schematic representation of the structure of composites with an interpretation of the probable mechanism of hardening of the material in the presence of a compatibilizer is given. It is shown that the crystallinity of the initial polyethylene has a significant effect on the hardening effect of composites. Electron microscopic micrographs of the structure of a filled composite without and with compatibilizer are given. A comparative assessment shows that in the presence of a compatibilizer, aluminum particles are in the bulk of the polymer matrix, i.e. are not in an isolated state. It is assumed that HDPE macrochains free of maleic anhydride (MA) are involved in the formation of crystalline formations, and small sections of macrosegments containing polar groups of MA are concentrated mainly in amorphous regions and in defects in crystalline structures in the form of passage chains. The concentration of PEMA macrosegments containing MA in the narrow amorphous space of HDPE favorably affects the increase in the adhesive forces of interaction on the surface of aluminum particles, which affects the preservation of the ultimate tensile stress at a relatively high level over a wide range of aluminum concentrations.


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