scholarly journals Influence of Compression Molding Process Parameters in Mechanical and Tribological Behavior of Hybrid Polymer Matrix Composites

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4195
Author(s):  
Thanikodi Sathish ◽  
Vinayagam Mohanavel ◽  
Thandavamoorthy Raja ◽  
Sinouvassane Djearamane ◽  
Palanivel Velmurugan ◽  
...  

In recent days, natural fibers are extremely influential in numerous applications such as automobile body building, boat construction, civil structure, and packing goods. Intensification of the properties of natural fibers is achieved by blending different natural fibers with resin in a proper mixing ratio. This investigation aims to synthesize a hybrid polymer matrix composite with the use of natural fibers of flax and loops of hemp in the epoxy matrix. The synthesized composites were characterized in terms of tribological and mechanical properties. The Taguchi L16 orthogonal array is employed in the preparation of composite samples as well as analysis and optimization of the synthesis parameters. The optimization of compression molding process parameters has enhanced the results of this investigation. The parameters chosen are percentage of reinforcement (20%, 30%, 40%, and 50%), molding temperature (150 °C, 160 °C, 170 °C, and 180 °C), molding pressure (1 MPa, 2 MPa, 3 MPa, and 4 MPa), and curing time (20 min, 25 min, 30 min, and 35 min). From the analysis, it was observed that the percentage of reinforcement is contributing more to altering the fatigue strength, and the curing time is influenced in the impact and wear analysis.

2014 ◽  
Vol 1692 ◽  
Author(s):  
Youngho Jin ◽  
Rosario A. Gerhardt

ABSTRACTThe electrical conductivity of insulating polymer matrix composites undergoes radical increase at a certain concentration of conductive filler, which is known as the percolation threshold. Polymer matrix conductive nanocomposites were fabricated by compression molding the mechanically mixed poly (methyl methacrylate) (PMMA) and antimony tin oxide (ATO) nanoparticles, as has been done with other polymer composites before. The electrical conductivity of PMMA/ATO nanocomposites increased by several orders of magnitude at a small concentration of ATO (∼ 0.27 vol %). The continuous 3D network like distribution of ATO nanoparticles contributed to this percolation at subcritical filler concentrations. The effects of processing parameters on these unique microstructures and electrical properties were investigated. The tetrakaidecahedron-like microstructure was observed by scanning electron microscopy (SEM) and was found to be affected by the molding pressure, temperature and amount of nanoparticles. The viscoelastic flow of matrix under the optimum processing conditions allowed the shape transformation of PMMA into space filling polyhedra and an ordered distribution of ATO nanoparticles along the sharp edges of the PMMA. Parametric finite element analysis was performed to model this unique microstructure-driven percolation. The 2D simplified model was generated in AC/DC frequency domain mode in COMSOL Multiphysics® to solve the effects of ordered distribution of conductive nanoparticles on the electrical properties of the composite. There was excellent agreement between experimental and simulated values of electrical conductivity and percolation concentration. This model can be used to predict percolation threshold and electrical properties for any types of composite systems containing insulating matrix and conductive fillers that can form this unique microstructure.


Author(s):  
Deepak Kumar ◽  
Sachin D Kore ◽  
Arup Nandy

This work studies an improved hybrid joining technique combining electromagnetic forming and adhesive joining to create a leak-tight Cu-SS tube-to-tube joint named as electromagnetically assisted adhesive joining (EAAJ). An experimental investigation is performed considering three discharge energy (3.9 kJ, 4.4 kJ and 5.0 kJ), four adhesive application lengths (20 mm, 15 mm, 10 mm and 5 mm), three adhesives (Loctite 638, Loctite 567, and Loctite SI 596) and four curing times (24 hours, 48 hours, 96 hours and 120 hours) as process parameters. The mechanical properties of the joints are investigated using testing techniques like pull-out, compression, and micro-hardness tests. An increase in joint strength is observed with the decrease in adhesive application length and increase in curing time. Maximum joint strength, 90% of the base copper tube strength, is obtained in the case of Loctite 638, with 5 mm of adhesive application length, 5.0 kJ of discharge energy and 96 hours of curing time. Furthermore, a three-way analysis (3-way ANOVA) of variance technique is implemented to calculate the contribution of the three factors (discharge energy, adhesive application length, type of adhesives) on the joint strength. A cohesive and adhesive failure mode combination leading to sliding failure mode is observed as a joint failure mechanism during pull-out and compression testing. A leak testing setup has been developed to investigate the joint’s leak tightness by an air pressure decay test. An increment in leak tightness by 1000 times is observed in 638 EAAJ samples compared to samples joined without adhesives. A 3-way ANOVA analysis is also performed to calculate the contribution of different factors on leak tightness of the joint. Micro-hardness is observed to be increased near the joint interface compared to the base metal. Deformation analysis has highlighted the impact of field shaper slit causing a non-uniformity in radial deformation in the circumferential direction and leading to non-uniform circumferential accumulation of adhesive.


2019 ◽  
Vol 16 (4) ◽  
pp. 157-175
Author(s):  
Burcu Kaya ◽  
Jan-Martin Kaiser ◽  
Karl-Friedrich Becker ◽  
Tanja Braun ◽  
Klaus-Dieter Lang

Abstract The quality of molded packages heavily depends on the process parameters of the molding process and on the material characteristics of epoxy molding compounds (EMCs). When defects are introduced into the electronic packages in one of the last steps in the manufacturing process, namely, during encapsulation, it may cause high failure costs. To decrease the number of defects due to the molding process, a comprehensive understanding of the impact of process parameters and variations in the characteristics of the EMC on package quality is necessary. This study aimed at supporting a deeper understanding of the influence of process parameters and variations in the material characteristics of the EMC on package quality. A systematic approach was introduced to generate a process model describing the correlation between process parameters and package quality to obtain optimum process parameters for the transfer molding process. The influence of the alterations in material characteristics of the EMC due to prolonged storage duration and humidity on void formation and wire sweep was investigated. An online monitoring method, dielectric analysis (DEA), was implemented into the transfer molding process to monitor the variations in the cure behavior of the EMC. A second molding compound was used to analyze the similarities in the alteration behavior of the molding compounds when subjected to the same preconditioning and to generalize the characteristic information obtained from DEA.


Author(s):  
M Najafi ◽  
A Darvizeh ◽  
R Ansari

One of the issues with the widespread use of polymer matrix composites in marine applications is their high susceptibility to environmental degradation, particularly hygrothermal conditions. Therefore, the present research intends to contribute to the better protection of the marine polymer matrix composites through the introduction of a newly developed fiber metal laminate for marine applications. This type of fiber metal laminate consists of a marine aluminum alloy of 5083 alternating with glass fiber reinforced epoxy composite layers. In order to evaluate the characterization of the environmental durability of this novel material, the specimens made of fiber metal laminates as well as commercial woven glass–epoxy composites were exposed to hygrothermal aging and hygrothermal cycling in boiling salt water. Then, to study the structural degradation caused by exposure to salt water, the mechanical properties of fiber metal laminate and woven glass–epoxy specimens under three-point bending and impact loading were evaluated. Results show that exposure to the saline environment generally decreased the flexural strength of woven glass–epoxy and fiber metal laminate specimens, whereas a smaller deterioration in flexural stiffness of both laminate types was found. Moreover, it was observed that the hygrothermal conditioning in salt water did not affect significantly the impact properties of both the fiber metal laminate and woven glass–epoxy specimens as compared to the flexural properties.


2021 ◽  
Vol 877 ◽  
pp. 3-8
Author(s):  
Prathumrat Nuyang ◽  
Atiwat Wiriya-Amornchai ◽  
Watthanaphon Cheewawuttipong

The effect of compatibilizer agent was studied when adding Aluminum fine powder (Al) to reinforce in Polypropylene (PP) by compared between polymer matrix composites (PMCs) and PMCs added Polypropylene graft maleic anhydride (PP-g-MAH).The average particle size of the aluminum fine powder was around 75 μm filled in polypropylene with different proportions of 2.5, 5, 7.5 and 10wt%. PMCs were prepared using the internal mixer. The results found that when the amount of aluminum fine powder increased, the mechanical properties had changed, i.e., tensile strength, and Young’s Modulus increased, while the impact strength and elongation at break decreased. But, when adding compatibilizer 1wt% it was found that the trend of tensile strength, and Young’s Modulus increased that compared with non-compatibilizer, but the impact strength and elongation at break decreased. The part of the morphology of PMCs with non-compatibilizer was found that the particle of aluminum fine powder dispersed in the matrix phase, but there were many microvoids between filler and matrix. But, PMCs with compatibilizer caused the microvoids between filler and matrix to be reduced.


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