Structure of blown films of polyethylene/polybutene‐1 blends

Nase, Michael; Funari, Sérgio S.; Michler, Goerg H.; Langer, Beate; Grellmann, W.; Androsch, René

doi:10.1002/pen.21526

Cited by 22 publications

(7 citation statements)

References 38 publications

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“…This superimposed orientation resulted in differences in the tensile responses of the films when tested in machine and cross-machine directions. Similar findings were reached by Godshall et al (2003) and Nase et al (2010). Zhang et al (2004) studied low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE) and HDPE films 25-100 ìm thick and found that the crystal morphology and orientation for these films are dependent on the take-up ratio (i.e., the stress applied during the manufacturing process).…”

Section: Introductionsupporting

confidence: 70%

Effects of blown film process on initial properties of HPDE geomembranes of different thicknesses

Ewais¹,

Rowe²

2014

Geosynthetics International

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The differences in the properties of five high density polyethylene geomembranes (GMBs) of different thicknesses made by the same manufacturer from same GMB resin are investigated. The 1.0, 1.5, 2.0 and 2.4 mm thick GMBs investigated were manufactured during the same production run by changing the pulling speed of the GMB out of the extrusion die, such that, the pulling speed decreased with increasing thickness. There were no differences in the initial HP-OIT or Std-OIT values of the different GMBs. However, there were differences in the key mechanical and physical properties of the GMBs that cannot be simply explained by the increase in the amount of material due to increasing GMB thickness. These differences are explained by differences in the morphological structure of the GMBs arising from the different thermal and stress histories experienced during the manufacturing process. The effects of the differences in the morphological structure are discussed in terms of: the decrease in the relative differences between the stress-elongation curves in the machine and cross-machine directions as thickness increases; changes in the enthalpies of melting and crystallisation by differential scanning calorimetry with changing thickness; and the different stress crack resistance (SCR) for the GMBs. For example, thinner GMBs had a greater difference between the SCR in the machine and cross-machine direction. Increasing the GMB thickness from 1.5 to 2.4 mm resulted in increasing the SCR from , 800 to , 1100 h in the cross-machine direction and decreasing its SCR from , 4100 to , 2000 h in the machine direction. Thus, GMBs of different thickness manufactured from the same resin can be expected to have differences in their physical and mechanical properties that are dependent on the additional material but also the difference in the tension and cooling rate experienced during the manufacturing process.

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Section: Introductionsupporting

confidence: 70%

Effects of blown film process on initial properties of HPDE geomembranes of different thicknesses

Ewais¹,

Rowe²

2014

Geosynthetics International

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“…Polyethylene (PE) films have been extensively investigated for decades and it is formally known that mechanical and fracture mechanics properties strongly depend, among others, on the crystalline phase orientation, which, in turn, is controlled by the processing conditions. [1][2][3][4][5][6][7] The crystalline phase orientation in blown films is complicated due to variable, sequential transverse and axial loadings. This causes crystal re-orientation during processing before cooling fixes the final structure.…”

Section: Introductionmentioning

confidence: 99%

Influence of low-density polyethylene blown film thickness on the mechanical properties and fracture toughness

Rennert

Nase

Lach³

et al. 2013

Journal of Plastic Film & Sheeting

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Recent research has shown that the resistance against crack initiation and propagation of polyethylene blown films depends on density, chain branching and crystal orientation next to the processing parameters. To assess low-density polyethylene blown film fracture toughness with different thicknesses, the essential work of fracture method has been conducted in this study. The thickness of the investigated low-density polyethylene films was regulated by the draw down ratio, which causes low-density polyethylene crystal orientation with the chain axis parallel to the machine direction at higher draw down ratios, influencing mechanical parameters and the fracture toughness. The crystal orientation was measured by X-ray diffraction. Blown films with thicknesses equal to or greater than 200 mm exhibit no preferred orientation, which is consistent with various calculated mechanical and fracture mechanics parameters. Films of less than 200 mm thickness show preferred machine direction crystal orientation and a distinct thickness influence on mechanical and fracture mechanics parameters.

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“…Figure 6(a,b) are images of needle-shaped deposits of alphacypermethrin present in optical micrographs taken on 1:1 m/m LDPE/ HDPE and LDPE films, respectively. The image in Figure 6(b) was captured with the sample placed between crossed polarisers, showing a rather dark/greyish appearing polymer matrix due to its semi-crystallinity and orientation of the macromolecules (Nase et al, 2010). Individual polymer crystals are too small to be detected in the distinct spherulitic crystalline-amorphous superstructure, typical for semi-crystalline PE crystallized from the quiescent melt, and is not seen due to crystallization during film blowing.…”

Section: 2mentioning

confidence: 99%

Blooming of insecticides from polyethylene mesh and film

Mapossa

Sibanda

Moyo

et al. 2021

Transactions of the Royal Society of South Africa

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Malaria remains a public health concern with vector control still the vital component of disease prevention, control, and elimination strategies. Recent years has seen a "stalling" in the progress made towards the reduction in the global malaria burden, highlighting the need to develop new, innovative, and safe alternative tools and delivery systems to achieve global malaria elimination. Interventions based on the use of indoor residual spraying (IRS) and long-life insecticidal bed nets (LLINs), i.e. insecticide-containing wall linings (IWLs), can contribute towards the reduction of malaria. Both LLINs and IWLs rely on the presence of insecticides on the fibre or filament surfaces. However, materials directly incorporating the insecticides into the polymer melt during extrusion, allows for effective killing of the mosquitoes when they come into contact with the surface of the material, only if there is insecticide present there. This means that the insecticide must migrate to the surface and precipitate there (bloom). Over time the internal concentration of insecticide will decay. This investigation was done using Fourier transform infrared spectroscopy (FTIR) in both the transmission and attenuated total reflection (ATR) modes to better understand the blooming of three World Health Organization-approved contact insecticides, i.e. alphacypermethrin, fipronil and chlorfenapyr, from mesh or film to better understand the likeliness of insecticides within the materials to migrate to the surface. Film-based samples were prepared in addition to wall lining mesh, because of their easier characterisation than the irregular shaped mesh filaments. FTIR, in ATR and in transmission modes, enabled the tracking of the migration of the three insecticides, over time to the surface of polyethylene mesh or film. This made it possible to estimate the apparent solubility of the insecticides in the polymer matrix. However, scanning electron microscopy (SEM) revealed that a portion of the insecticide is trapped, in a crystalline state, inside the polymer matrix. These results suggest the possibility of developing products-based insecticides for protection against infective mosquito bites in malaria-endemic regions.

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Structure of blown films of polyethylene/polybutene‐1 blends

Cited by 22 publications

References 38 publications

Effects of blown film process on initial properties of HPDE geomembranes of different thicknesses

Effects of blown film process on initial properties of HPDE geomembranes of different thicknesses

Influence of low-density polyethylene blown film thickness on the mechanical properties and fracture toughness

Blooming of insecticides from polyethylene mesh and film

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