scholarly journals Elaboration of nanostructured polyurethane foams/OMMT using a twin-screw extruder in counter-rotating mode

2018 ◽  
Vol 83 (12) ◽  
pp. 1363-1378
Author(s):  
Yasmine Mahmoud ◽  
Zitouni Safidine ◽  
Hichem Zeghioud

In this work, a new elaboration method for nanostructured foam polyurethane/ organo-modified montmorillonite (PUR/OMMT) by in situ polymerization is proposed. A twin-screw extruder in the contra-rotation mode combined with reaction injection molding (RIM) as the polymerization process was used. The blended polyols, copolymer polyol (CPP) were included between the OMMT layers via the twin-screw extruder. Both the formulation of the PUR and the inter-foliar distance in the montmorillonite (MMT) were optimized. The effect of some parameters such as OMMT content and catalyst (triethylenediamine for PUR 3 and triethylenediamine+diamino-1,2 propane for PUR 4) was also investigated. The synthesized materials (OMMT, PUR and PUR/OMMT) were characterized by different methods, i.e., Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results of evaluation tests, such as flammability and the tensile for the PUR 3+OMMT foams revealed that the optimum properties were obtained for PUR 3+2 % OMMT. The PUR 4 foam showed better mechanical and flame- -retardant properties than the PUR 3 (r = ?NCO/?OH = 1.15) foam. However, the PUR 4 + 2 % OMMT formula exhibited the most delayed flame diffusion and pronounced rigidity.

1996 ◽  
Vol 11 (2) ◽  
pp. 139-146 ◽  
Author(s):  
A. De Loor ◽  
P. Cassagnau ◽  
A. Michel ◽  
L. Delamare ◽  
B. Vergnes

2005 ◽  
Vol 82 (5) ◽  
pp. 574-581 ◽  
Author(s):  
Hanwu Lei ◽  
R. Gary Fulcher ◽  
Roger Ruan ◽  
Bernhard van Lengerich

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1058
Author(s):  
Hikaru Okubo ◽  
Haruka Kaneyasu ◽  
Tetsuya Kimura ◽  
Patchiya Phanthong ◽  
Shigeru Yao

Each year, increasing amounts of plastic waste are generated, causing environmental pollution and resource loss. Recycling is a solution, but recycled plastics often have inferior mechanical properties to virgin plastics. However, studies have shown that holding polymers in the melt state before extrusion can restore the mechanical properties; thus, we propose a twin-screw extruder with a molten resin reservoir (MSR), a cavity between the screw zone and twin-screw extruder discharge, which retains molten polymer after mixing in the twin-screw zone, thus influencing the polymer properties. Re-extruded recycled polyethylene (RPE) pellets were produced, and the tensile properties and microstructure of virgin polyethylene (PE), unextruded RPE, and re-extruded RPE moldings prepared with and without the MSR were evaluated. Crucially, the elongation at break of the MSR-extruded RPE molding was seven times higher than that of the original RPE molding, and the Young’s modulus of the MSR-extruded RPE molding was comparable to that of the virgin PE molding. Both the MSR-extruded RPE and virgin PE moldings contained similar striped lamellae. Thus, MSR re-extrusion improved the mechanical performance of recycled polymers by optimizing the microstructure. The use of MSRs will facilitate the reuse of waste plastics as value-added materials having a wide range of industrial applications.


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