Parametric and mechanical characterization of linear low density polyethylene (LLDPE) using rotational moulding technology

Ramkumar, Pl.; Kulkarni, Deepak; Chaudhari, Vikas

doi:10.1007/s12046-013-0223-4

Cited by 19 publications

(14 citation statements)

References 17 publications

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“…The shortest cycle time recorded for PIAT of 185 • C (real PIAT of 201 • C due to overshooting) was about 38 min, whereas the longest cycle time recorded for PIAT of 235 • C (real PIAT of 238 • C) was about 43 min. The variations in the mold internal air temperature can be directly related to the materials and processing conditions and are very sensitive to differentiate between the samples as reported in other studies (Cramez et al, 2002;Ramkumar et al, 2014). Table 3 depicts the image of parts obtained at each PIAT and its effect on the color parameters in comparison to natural cork.…”

Section: Effect Of Mold Internal Air Temperaturementioning

confidence: 83%

Processing–Structure–Properties of Cork Polymer Composites

Martins

Gil

2020

Front. Mater.

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This work aims at presenting a new strategy for the use of cork by-products on the development of sustainable composites with potential applications in rotational molding. In this study, different cork granulometries (0.15-3 mm) and matrix/cork ratios (90/10, 85/15, 80/20) are analyzed to access the processability of medium-density polyethylene (MDPE) with cork by rotational molding. The influence of processing parameters, such as the mold peak internal air temperature (PIAT) (200-240 • C), is analyzed and correlated with the aesthetics, morphological and mechanical properties of the parts. The aim is to obtain a complete understanding of the processing-structure-property relationships. Defect-free parts are obtained with thin granulometric cork powders at a maximum of 10% by weight in PE/cork composites. The increase in cork content reduces the sintering capability and increases the porosity, wall thickness, and surface defects, simultaneously weakening the mechanical properties. The increase in PIAT favors a more compact structure and reveals better impact properties. All the parts are soft on touch and transmit the comfort and sensation of warm feeling of the cork. Moreover, lightweight parts and hydrophobic surfaces are achieved from the cork intrinsic properties. As a natural material, cork darkens its color with temperature, which is attributed to the reactions of the extractives within the components of cork, with no degradation associated. The work shows that polymer cork composites (CPC) are suitable for rotational molding within the processing window characteristic of PE, to achieve innovative and sustainable products with unique aesthetics and functionalities given by the cork material.

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Section: Effect Of Mold Internal Air Temperaturementioning

confidence: 83%

Processing–Structure–Properties of Cork Polymer Composites

Martins

Gil

2020

Front. Mater.

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“…When the ACA was present the PIAT increased by about 2 • C because of the exothermic reaction of the ACA decomposition. Nevertheless, PIAT variations can be directly related to the materials and processing conditions and is very sensitive to differentiate between the samples as reported in other studies [21,[29][30][31].…”

Section: Thermogravimetry Analyzesmentioning

confidence: 86%

Morphological and Mechanical Properties of Bilayers Wood-Plastic Composites and Foams Obtained by Rotational Molding

et al. 2020

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In this work, the suitability for the production of sustainable and lightweight materials with specific mechanical properties and potentially lower costs was studied. Agave fiber (AF), an agro-industrial waste, was used as a reinforcement and azodicarbonamide (ACA) as a chemical blowing agent (CBA) in the production of bilayer materials via rotational molding. The external layer was a composite of linear medium density polyethylene (LMDPE) with different AF contents (0–15 wt %), while the internal layer was foamed LMDPE (using 0–0.75 wt % ACA). The samples were characterized in terms of thermal, morphological and mechanical properties to obtain a complete understanding of the structure-properties relationships. Increases in the thicknesses of the parts (up to 127%) and a bulk density reduction were obtained by using ACA (0.75 wt %) and AF (15 wt %). Further, the addition of AF increased the tensile (23%) and flexural (29%) moduli compared to the neat LMDPE, but when ACA was used, lower values (75% and 56% for the tensile and flexural moduli, respectively) were obtained. Based on these results, a balance between mechanical properties and lightweight can be achieved by selecting the AF and ACA contents, as well as the performance and aesthetics properties of the rotomolded parts.

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“…This is crucial for the mechanical properties of the finished part such as tensile, impact, and flexural strength. [7][8][9] The powder-mold contact time is critical to allow the most heat energy to transfer to the powder bed through conduction (the dominant means of heat transfer) over a set period. 10 An appropriate speed would allow sufficient time for the heat energy from the mold to transfer to the powder.…”

Section: Literature Reviewmentioning

confidence: 99%

Motion control for uniaxial rotational molding

Adams

Jin

Barnes

et al. 2020

J of Applied Polymer Sci

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Motion control parameters of rotational molding can affect process efficiency and product quality. Different motion control schemes will lead to varied powder flow regimes exhibiting different levels of mixing and temperature uniformity. The change in nature of powder flow during a molding cycle suggests that varying the rotational speed could improve the powder mixing and temperature uniformity, therefore potentially reducing processing time and energy consumption. Experiments completed investigating powder flow under uniaxial rotation show that savings of up to 2.5% of the heating cycle time can be achieved. This validates the hypothesis that altering the rotational speed to maintain the ideal powder flow throughout the heating cycle can be utilized to reduce the time taken for all the polymer powder to adhere to the mold wall. The effect of rotational speed on wall thickness uniformity and impact strength were investigated and discussed. Results show a strong influence of rotational speed (and powder flow) on the wall thickness uniformity of the moldings with wall thickness uniformity deviations of up to 50% found (within the 2-35 RPM speed range tested).

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Parametric and mechanical characterization of linear low density polyethylene (LLDPE) using rotational moulding technology

Cited by 19 publications

References 17 publications

Processing–Structure–Properties of Cork Polymer Composites

Processing–Structure–Properties of Cork Polymer Composites

Morphological and Mechanical Properties of Bilayers Wood-Plastic Composites and Foams Obtained by Rotational Molding

Motion control for uniaxial rotational molding

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