Effect of processing parameters on fusion and mechanical properties of a twin-screw extruded rigid PVC pipe

2003 ◽  
Vol 9 (2) ◽  
pp. 81-89 ◽  
Author(s):  
M. Moghri ◽  
H. Garmabi ◽  
M. Akbarian
2007 ◽  
Vol 15 (5) ◽  
pp. 365-370 ◽  
Author(s):  
L.M. Matuana ◽  
S. Cam ◽  
K.B. Yuhasz ◽  
Q.J. Armstrong

This study examined both the use of acrylonitrile-butadiene-styrene (ABS) as a plastic matrix for wood-plastic composites (WPCs) and the effect of impact modification on the mechanical properties of ABS/wood-flour composites. Blends of ABS filled with wood flour (both pine and maple) were processed into profile shape using a conical twin-screw extruder and the mechanical properties of the resulting composites were characterised and compared to WPCs made with polyolefins (HDPE and PP) and rigid PVC matrices. Generally, WPCs made with ABS matrix outperformed their polyolefin counterparts in both flexural strength and modulus, whereas ABS-based composites had inferior strength but greater modulus than those made with rigid PVC. The impact strength of ABS/wood-flour composites was below that of wood plastic composites made with polyolefins. However, impact modification with acrylonitrile-butadiene-styrene terpolymers had some effect in toughening of the ABS/wood-flour composites.


2013 ◽  
Vol 58 (1) ◽  
pp. 95-98 ◽  
Author(s):  
M. Zielinska ◽  
J. Sieniawski

Superalloy René 77 is very wide used for turbine blades, turbine disks of aircraft engines which work up to 1050°C. These elements are generally produced by the investment casting method. Turbine blades produced by conventional precision casting methods have coarse and inhomogeneous grain structure. Such a material often does not fulfil basic requirements, which concern mechanical properties for the stuff used in aeronautical engineering. The incorporation of controlled grain size improved mechanical properties. This control of grain size in the casting operation was accomplished by the control of processing parameters such as casting temperature, mould preheating temperature, and the use of grain nucleates in the face of the mould. For nickel and cobalt based superalloys, it was found that cobalt aluminate (CoAl2O4) has the best nucleating effect. The objective of this work was to determine the influence of the inoculant’s content (cobalt aluminate) in the surface layer of the ceramic mould on the microstructure and mechanical properties at high temperature of nickel based superalloy René 77. For this purpose, the ceramic moulds were made with different concentration of cobalt aluminate in the primary slurry was from 0 to 10% mass. in zirconium flour. Stepped and cylindrical samples were casted for microstructure and mechanical examinations. The average grain size of the matrix ( phase), was determined on the stepped samples. The influence of surface modification on the grain size of up to section thickness was considered. The microstructure investigations with the use of light microscopy and scanning electron microscopy (SEM) enable to examine the influence of the surface modification on the morphology of ’ phase and carbides precipitations. Verification of the influence of CoAl2O4 on the mechanical properties of castings were investigated on the basis of results obtained form creep tests.


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.


Author(s):  
Zahid Iqbal Khan ◽  
Zurina Binti Mohamad ◽  
Abdul Razak Bin Rahmat ◽  
Unsia Habib ◽  
Nur Amira Sahirah Binti Abdullah

This work explores a novel blend of recycled polyethylene terephthalate/polyamide 11 (rPET/PA11). The blend of rPET/PA11 was introduced to enhance the mechanical properties of rPET at various ratios. The work’s main advantage was to utilize rPET in thermoplastic form for various applications. Three different ratios, i.e. 10, 20 and 30 wt.% of PA11 blend samples, were prepared using a twin-screw extruder and injection moulding machine. The mechanical properties were examined in terms of tensile, flexural and impact strength. The tensile strength of rPET was improved more than 50%, while the increase in tensile strain was observed 42.5% with the addition of 20 wt.% of PA11. The improved properties of the blend were also confirmed by the flexural strength of the blends. The flexural strength was increased from 27.9 MPa to 48 MPa with the addition of 30 wt.% PA11. The flexural strain of rPET was found to be 1.1%. However, with the addition of 10, 20 and 30 wt.% of PA11, the flexural strain was noticed as 1.7, 2.1, and 3.9% respectively. The impact strength of rPET/PA11 at 20 wt.% PA11 was upsurged from 110.53 to 147.12 J/m. Scanning electron microscopy analysis revealed a dispersed PA11 domain in a continuous rPET matrix morphology of the blends. This work practical implication would lead to utilization of rPET in automobile, packaging, and various industries.


2021 ◽  
Author(s):  
D. Prasuna Lilly Florence ◽  
P. H. V. Sesha Talpa Sai ◽  
S. Devaraj ◽  
K. S. Narayanaswamy

2019 ◽  
Vol 299 ◽  
pp. 06007
Author(s):  
Mircea Aurelian Antoniu Rusu ◽  
Sever-Adrian Radu ◽  
Catalin Moldovan ◽  
Codruta Sarosi ◽  
Ionela Amalia Mazilu (Moldovan) ◽  
...  

Although polyethylene terephthalate (PET) is a champion of recycling, intense research is being done to find new solutions for using recycled plastic. This study aims to characterize the mechanical andstructural properties (SEM- scanning electron microscopy) of products made from recycled metal swarf or mesh wire with recycled plastic (PET) in comparison with virgin plastic. Samples manufactured from virgin and recycled PET are made by pressing and high temperature. The loss of mechanical properties ofproducts made from recycled plastic is a major drawback that influences their use. SEM images confirm that the dispersion and distribution of the PET phase is not very uniform. By addition of virgin plastic in various compositions with recycled plastic, processing parameters and mechanical properties can be optimized.


Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1273 ◽  
Author(s):  
Barry Mooney ◽  
Kyriakos Kourousis

Maraging steel is an engineering alloy which has been widely employed in metal additive manufacturing. This paper examines manufacturing and post-processing factors affecting the properties of maraging steel fabricated via laser powder bed fusion (L-PBF). It covers the review of published research findings on how powder quality feedstock, processing parameters, laser scan strategy, build orientation and heat treatment can influence the microstructure, density and porosity, defects and residual stresses developed on L-PBF maraging steel, with a focus on the maraging steel 300 alloy. This review offers an evaluation of the resulting mechanical properties of the as-built and heat-treated maraging steel 300, with a focus on anisotropic characteristics. Possible directions for further research are also identified.


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