Mechanical Behavior of Polyurethane Composite Foams from Kenaf Fiber and Recycled Tire Rubber Particles

In the present work polyurethane foams containing various content loadings of kenaf fiber and recycled tire rubber particulates were prepared and studied, with the objective of developing alternative composite rigid foams. The influence of the filler content on the foam microstructure and its physical and mechanical behavior has been studied for three different polyurethane resin densities. Microstructural observation on fracture surface of composites was carried out using scanning electron microscopy. It has shown closed spherical cells with reduced size when the fillers are added. Nevertheless, the incorporation of kenaf fiber and recycled tire rubber particulates that refined at 80 mesh led to higher mechanical properties than that unfilled polyurethane foam. A 6% filler content loading exhibited the optimum compression stress and compression modulus, while further increase of filler content loading resulted in decline in mechanical behavior. The presence of larger filler content deteriorated the polyurethane system cellular structure and lead to poor composites strength. Overall, the use of kenaf fiber and recycled tire rubber particulates gives composite foams with comparable mechanical behavior for the studied filler reinforcement level.

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Polyurethane Composite Foams Synthesized Using Bio-Polyols and Cellulose Filler

Materials ◽

10.3390/ma14133474 ◽

2021 ◽

Vol 14 (13) ◽

pp. 3474

Author(s):

Katarzyna Uram ◽

Milena Leszczyńska ◽

Aleksander Prociak ◽

Anna Czajka ◽

Michał Gloc ◽

...

Keyword(s):

Cross Sections ◽

Raw Materials ◽

Polyurethane Foams ◽

Degree Of Crystallinity ◽

X Ray Diffraction ◽

Polyurethane Composite ◽

Composite Foams ◽

Closed Cell ◽

Ft Ir ◽

The Fourier Transform

Rigid polyurethane foams were obtained using two types of renewable raw materials: bio-polyols and a cellulose filler (ARBOCEL® P 4000 X, JRS Rettenmaier, Rosenberg, Germany). A polyurethane system containing 40 wt.% of rapeseed oil-based polyols was modified with the cellulose filler in amounts of 1, 2, and 3 php (per hundred polyols). The cellulose was incorporated into the polyol premix as filler dispersion in a petrochemical polyol made using calenders. The cellulose filler was examined in terms of the degree of crystallinity using the powder X-ray diffraction PXRD -and the presence of bonds by means of the fourier transform infrared spectroscopy FT-IR. It was found that the addition of the cellulose filler increased the number of cells in the foams in both cross-sections—parallel and perpendicular to the direction of the foam growth—while reducing the sizes of those cells. Additionally, the foams had closed cell contents of more than 90% and initial thermal conductivity coefficients of 24.8 mW/m∙K. The insulation materials were dimensionally stable, especially at temperatures close to 0 °C, which qualifies them for use as insulation at low temperatures.

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Improvement of thermal conductivity of rigid polyurethane foams with aluminum nitride filler

Cellular Polymers ◽

10.1177/0262489321988970 ◽

2021 ◽

pp. 026248932198897

Author(s):

Serife Akkoyun ◽

Meral Akkoyun

Keyword(s):

Thermal Conductivity ◽

Aluminum Nitride ◽

Polyurethane Foams ◽

Thermal Transitions ◽

Rigid Polyurethane Foams ◽

Noticeable Increase ◽

Polyurethane Composite ◽

Composite Foams ◽

Step Procedure ◽

Electrical Conductivities

The aim of this work is the fabrication of electrically insulating composite rigid polyurethane foams with improved thermal conductivity. Therefore, this study is focused on the effect of aluminum nitride (AlN) on the thermal and electrical conductivities of rigid polyurethane foams. For this purpose, aluminum nitride/rigid polyurethane composite foams were prepared using a three-step procedure. The electrical and thermal conductivities of the foams were characterized. The thermal transitions, mechanical properties and morphology of the foams were also examined. The results reveal that AlN induces an increase of the thermal conductivity of rigid polyurethane foam of 24% which seems to be a relatively noticeable increase in polymeric foams. The low electrical conductivity of the foams is preserved.

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The Impact of Ground Tire Rubber Oxidation with H2O2 and KMnO4 on the Structure and Performance of Flexible Polyurethane/Ground Tire Rubber Composite Foams

Materials ◽

10.3390/ma14030499 ◽

2021 ◽

Vol 14 (3) ◽

pp. 499

Author(s):

Aleksander Hejna ◽

Adam Olszewski ◽

Łukasz Zedler ◽

Paulina Kosmela ◽

Krzysztof Formela

Keyword(s):

Mechanical Performance ◽

Hydroxyl Groups ◽

Tire Rubber ◽

Economic Implications ◽

Ground Tire Rubber ◽

Polyurethane Composite ◽

Composite Foams ◽

And Performance ◽

Flexible Polyurethane ◽

The Impact

The use of waste tires is a very critical issue, considering their environmental and economic implications. One of the simplest and the least harmful methods is conversion of tires into ground tire rubber (GTR), which can be introduced into different polymer matrices as a filler. However, these applications often require proper modifications to provide compatibility with the polymer matrix. In this study, we examined the impact of GTR oxidation with hydrogen peroxide and potassium permanganate on the processing and properties of flexible polyurethane/GTR composite foams. Applied treatments caused oxidation and introduction of hydroxyl groups onto the surface of rubber particles, expressed by the broad range of their hydroxyl numbers. It resulted in noticeable differences in the processing of the polyurethane system and affected the structure of flexible composite foams. Treatment with H2O2 resulted in a 31% rise of apparent density, while the catalytic activity of potassium ions enhanced foaming of system decreased density by 25% and increased the open cell content. Better mechanical performance was noted for H2O2 modifications (even by 100% higher normalized compressive strength), because of the voids in cell walls and incompletely developed structure during polymerization, accelerated by KMnO4 treatment. This paper shows that modification of ground tire rubber is a very promising approach, and when properly performed may be applied to engineer the structure and performance of polyurethane composite foams.

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Synthesis, Characterization and Mechanical Properties of Novel Bio-Based Polyurethane Foams Using Cellulose-Derived Polyol for Chain Extension and Cellulose Citrate as a Thickener Additive

Polymers ◽

10.3390/polym13162802 ◽

2021 ◽

Vol 13 (16) ◽

pp. 2802

Author(s):

Loredana Maiuolo ◽

Fabrizio Olivito ◽

Vincenzo Algieri ◽

Paola Costanzo ◽

Antonio Jiritano ◽

...

Keyword(s):

Mechanical Properties ◽

Mechanical Tests ◽

Reduction Reaction ◽

Polyurethane Foams ◽

Chain Extension ◽

Polyurethane Composite ◽

Composite Foams ◽

Bio Oil ◽

Ft Ir ◽

Flexible Polyurethane

A novel series of bio-based polyurethane composite foams was prepared, employing a cellulose-derived polyol for chain extension and cellulose-citrate as a thickener additive. The utilized polyol was obtained from the reduction reaction of cellulose-derived bio-oil through the use of sodium borohydride and iodine. Primarily, we produced both rigid and flexible polyurethane foams through chain extension of the prepolymers. Secondly, we investigated the role of cellulose citrate as a polyurethane additive to improve the mechanical properties of the realized composite materials. The products were characterized by FT-IR spectroscopy and their morphologies were analysed by SEM. Mechanical tests were evaluated to open new perspectives towards different applications.

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