Effects of lubricants on the rheological and mechanical properties of wood flour/polypropylene composites

The main objective of the presented scientific article is to define the mechanical properties of polypropylene homopolymer with a prescribed percentage ratio of recycled granulate. The chosen material is intended for injection molding and especially for the production of products made by additive technologies. Experimental verification of the mechanical properties was realized by testing samples produced with various concentrations of the recycled material. Experimental samples underwent tests to obtain the mechanical properties of the produced new material. These tests included rheological tests, tensile and flexural tests as well as and Charpy impact toughness tests. These mechanical tests were conducted according to ISO standards valid for the individual testing method. Testing methods were carried out using prescribed numbers of testing samples. The presented scientific article is also focused on changes in microstructures of testing materials in relation to the percentage ratio of recycled granulate. Recycled granulate of thermoplastic was not necessity for additional modifications.

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“…6. The results also confirm the conclusions of Sahli et al [18], Dai et al [19], and Spicker et al [20].…”

Section: Description Of the Experimentssupporting

confidence: 91%

Implementation of a Recycled Polypropylene Homopolymer Material for Use in Additive Manufacturing

et al. 2021

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“…At low frequencies (i.e., less than 1 rad/s), if the wood content is below 30 wt.%, the complex viscosity curve displays a Newtonian-like plateau [ 14 , 92 ], and the behavior is mostly influenced by the polymer-polymer interactions. At higher wood content, filler-polymer interactions become more important; thus, the Newtonian plateau reduces and tends to disappear [ 13 , 65 , 77 , 89 , 92 , 95 ], as shown in Figure 1 b (curve C). At even higher wood percentages, filler-filler interactions are dominant, and yield phenomena may appear in some systems ( Figure 1 b, curve D).…”

Section: Wpc Characterization With Rotational Rheometersmentioning

confidence: 99%

“…Like in pressure-driven viscometry, coupling agents [ 77 , 79 , 82 , 90 , 101 , 102 , 103 ] and lubricants [ 58 , 95 , 101 ] are the additives that were mostly investigated with rotational rheometry. Usually, the main coupling agents that are used are MAPE and MAPP when HDPE or PP are used as matrix [ 60 , 77 , 79 , 82 , 101 , 102 , 103 ] but their effect on the rheological properties is still debated.…”

Section: Wpc Characterization With Rotational Rheometersmentioning

confidence: 99%

“…Lubricants are also very common and their effects are studied also with rotational rheometers [ 58 , 95 , 101 ]. Stearic acid, semi-refined paraffin wax, and zinc stearate reduce complex viscosity, and this effects increases with the increase of lubricant content, but the best compromise seems to be obtained by combining stearic acid with wax lubricants [ 95 ] or with MAH coupled with ester-type lubricants [ 58 , 101 ]. In the first system, stearic acid decreases the polarity of the wood particles, while wax acts as an internal lubricant in the second system.…”

Section: Wpc Characterization With Rotational Rheometersmentioning

confidence: 99%

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A Review of Wood Polymer Composites Rheology and Its Implications for Processing

Mazzanti

Mollica

2020

Polymers

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Despite the fact that wood polymer composites are interesting materials for many different reasons, they are quite difficult to shape through standard polymer processing techniques, such as extrusion or injection molding. Rheological characterization can be very helpful for understanding the role played by the many variables that are involved in manufacturing and to achieve a good quality final product through an optimized mix of formulation and processing parameters. The main methods that have been used for the rheological characterization of these materials are capillary and parallel plate rheometry. Both are very useful: rotational rheometry is particularly convenient to investigate the compounding phase and obtain structural information on the material, while capillary viscometry is well suited to understand final manufacturing. The results available in the literature at the moment are indeed very interesting and are mostly aimed at investigating the influence of the material formulation, the additives in particular, on the structural, mechanical, and morphological properties of the composite: despite a good number of papers, though, it is difficult to draw general conclusions, as many issues are still debated. The purpose of this article was to overview the state of the art and to highlight the issues that deserve further investigation.

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“…64 During polymerization, the additives migrate to the resin-die region and serve as lubricants, thereby reducing friction between the pultruded profile and die surfaces. 77 However, special care should be taken when using this type of additives as they can affect the physical properties, visual appearance, and paintability of the manufactured profiles.…”

Section: Introductionmentioning

confidence: 99%

Effects of additives on the cure kinetics of vinyl ester pultrusion resins

Vedernikov

Nasonov

Korotkov

et al. 2021

Journal of Composite Materials

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Pultrusion is a highly efficient composite manufacturing process. To accurately describe pultrusion, an appropriate model of resin cure kinetics is required. In this study, we investigated cure kinetics modeling of a vinyl ester pultrusion resin (Atlac 430) in the presence of aluminum hydroxide (Al(OH)3) and zinc stearate (Zn(C18H35O2)2) as processing additives. Herein, four different resin compositions were studied: neat resin composition, composition with Al(OH)3, composition comprising Zn(C18H35O2)2, and composition containing both Al(OH)3 and Zn(C18H35O2)2. To analyze each composition, we performed differential scanning calorimetry at the heating rates of 5, 7.5, and 10 K/min. To characterize the cure kinetics of Atlac 430, 16 kinetic models were tested, and their performances were compared. The model based on the [Formula: see text]th-order autocatalytic reaction demonstrated the best results, with a 4.5% mean squared error (MSE) between the experimental and predicted data. This study proposes a method to reduce the MSE resulting from the simultaneous melting of Zn(C18H35O2)2. We were able to reduce the MSE by approximately 34%. Numerical simulations conducted at different temperatures and pulling speeds demonstrated a significant influence of resin composition on the pultrusion of a flat laminate profile. Simulation results obtained for the 600 mm long die block at different die temperatures (115, 120, 125, and 130 °C) showed that for a resin with a final degree of cure exceeding 95% at the die exit, the maximum difference between the predicted values of pulling speed for a specified set of compositions may exceed 1.7 times.

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Effects of lubricants on the rheological and mechanical properties of wood flour/polypropylene composites

Cited by 19 publications

References 49 publications

Implementation of a Recycled Polypropylene Homopolymer Material for Use in Additive Manufacturing

Implementation of a Recycled Polypropylene Homopolymer Material for Use in Additive Manufacturing

A Review of Wood Polymer Composites Rheology and Its Implications for Processing

Effects of additives on the cure kinetics of vinyl ester pultrusion resins

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