Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : polymer

Effect of Different Laser Welding Parameter on Welding Strength in Polymer Transmission Welding Using Semiconductor

Farah M. Shaker; Mohanned M. AL-Khafaji; Kadhim A. Hubeatir

Engineering and Technology Journal, 2020, Volume 38, Issue 5, Pages 761-768
DOI: 10.30684/etj.v38i5A.368

In this work, the diode laser (810μm wavelength) was used for laser transmission welding application on PMMA (polymethylmethacrylate). The welding was done between opaqueness and transparent with thickness 2 mm and 2.57 mm, respectively. The effects of different process parameters, laser speed, spot size and force with different values (5, 15, 20 mm/min), (2, 2.5, 3mm) and (2, 6, 10 N) respectively were used to study their effect on weld width and strength. L9 Taguchi orthogonal array has been used to design the experiments and optimize the result. The result of the signal to noise ratio shows that, the width of welding decrease with increasing both the welding speed and the spot size while it was increased with increasing the force on the sample. The narrower width observed at speed (20mm/min), spot size (3mm), and force (2N). Also, the best strength was found at speed (15 mm/min), spot size (2.5mm), and force (10N).

Drag Reduction Study of Xathan Gum with Polydiallyldimethylammonium Chloride (PDDAC) Solutions in Turbulent Flow

Zainab Yousif

Engineering and Technology Journal, 2018, Volume 36, Issue 8A, Pages 891-899
DOI: 10.30684/etj.336.8A.8

The transportation of liquids through pipelines is attributed with high-energy consumption due to the turbulent nature of their transportation. Low concentrations of polymeric additives were proven effective flow enhancing agent when injected into these pipelines due to its viscoelastic property capable of suppressing the turbulent structures; however, the mechanical degradation of polymers is a disadvantage, which can be controlled efficiently by using complex in a surfactant- polymer interface. In this presented work, turbulent drag reduction (DR) efficacy of anionic Xathan gum and nonionic surfactant (PDDAC) regarding the surfactant -polymer interface was studied using a rotating disk apparatus (RDA) technique and pipeline. The effect of surfactant addition, critical concentration of XG, and the dependence of drag reduction on the turbulent strength from the rotation speed were also studied. The critical behavior of the interface was found at XG (700 ppm) and (1000-ppm) concentrations, respectively. The drag reduction (~70%) was observed at critical concentration behavior, which is largely reliant on the alkyl chain in the surfactant molecule. The result of the a rotating disk apparatus (RDA) gave about 51% drag reduction with the Xanthan gum alone while in the pipe, about 58% drag reduction percent (DR%) was obtained. (PDDAC) alone yielded about 32% and 36% drag reduction in the rotating disk apparatus (RDA) and pipe respectively. However, combining the Xanthan gum polymer and Polydiallyldimethylammonium chloride (PDDAC) surfactant gave 62% drag reduction. Thus, it could be inferred that the combination of these duo has greater impact than the individual materials. It could thus be concluded that the complex formed by these materials is another form of drag reducing agents.

Performance of Powdered Polymerized Concrete at Elevated Temperatures

Dina Mukheef Hamza

Engineering and Technology Journal, 2013, Volume 31, Issue 5, Pages 932-950
DOI: 10.30684/etj.31.5A10

In the domain of concrete modification by using polymers, the present study, focused on the use of Carboxy-Methyl Cellulose (CMC) as a water-soluble polymer and investigate its effects on the behavior of concrete. The study include two issues, the first one is the effect of polymer adding method on mechanical properties of concrete such as compressive strength, tensile strength and modulus of elasticity in additional to impact resistance and the second is the effect of graded temperature on these properties. The polymer/cement ratio used herein is 3%, this ratio never used before in the previous researches on many types of water soluble powder polymers.
Three concrete batches were prepared, the first is the reference one as a normal concrete (NOR), the second is a polymerized concrete (POL1) where the polymer added as a latex, and the last also as a polymerized concrete (POL2) but the polymer added as a powder.Each batch contains twelve cubic specimens (100x100x100)mm for compressive strength test, three cubes for each level of temperature, eight cylindrical specimens (150x300)mm for splitting tensile strength test, two cylinders for each level of temperature, and four paneled specimens (450x450x50)mm for impact resistance test, one panel for each level of temperature.
It can be considered from the results that when the polymer CMC used herein added as a latex will give better strength behavior in polymerized concrete than the one which added as a powder by about 28.86% in compressive strength, 19% in splitting tensile strength, very high percent in modulus of elasticity and 16.66% in impact resistance. On the other hand, it is found that the temperature level of 200°C will affect the behavior of polymerized concrete and that contrast with the behavior of normal concrete while in temperature levels 400°C and 600°C the effects on polymerized concrete will be more slightly and more clearly on normal concrete.

Improving the Compatibility between Polymer-, Pozzolanic Cement-Based Repairing Materials and Concrete Substrate

Qais J. Frayyeh; Maan S. Hassan; Tahseen D. Saadoon

Engineering and Technology Journal, 2013, Volume 31, Issue 4, Pages 661-676
DOI: 10.30684/etj.31.4A.5

In this study, the compatibility of five different cement based repair materials and substrate concrete was investigated in three stages. First stage includes studying the individual properties of repair materials, and also two types of concrete, such as compressive strength, flexural strength, and dry shrinkage using BS 1881: part 116, ASTM C78-06, ASTM C157 -06 test procedure respectively. Second stage includes evaluating the bond strength of composite cylinder for different combinations of repair materials and substrate concrete. Third stage includes investigating the compatibility using a composite beam of repair material and substrate concrete under third point loading.
The experimental results show that one individual property has no crucial effect on the success of concrete repair system. Bond strength and dry shrinkage however has a strong indication about the compatibility.

The Effect of Solvent Additions on theMechanical Properties of Epoxy

Khalid K. Abbass; Akram R. Jabur; Saad B. H. Farid

Engineering and Technology Journal, 2010, Volume 28, Issue 18, Pages 5732-5743

The effect of the TolueneC6H5CH3 and Acetone (CH3)2CO additions on the
mechanical properties of cured Epoxy is studied. Different weight percentages of
Toluene (0, 4, 8, 10 & 14 wt%) and Acetone (0, 3, 5, 8 & 10 wt%) were used
under curing temperatures (40°C and 60°C) for Toluene and 40°C for Acetone
with curing time of 24hrs. The results show improved mechanical properties
(Young modulus and Fracture stress) for Epoxy samples cured at 40°C with the
increase of Toluene to a maximum of 8wt%, then these properties are degraded as
the Toluene percentage increase. In the contrary, the Epoxy samples cured at 60 °C
shows poorer properties with increased weight percentages of the Toluene.
Epoxy samples thinned with different amount of Acetone solvent is
prepared and cured. These samples show best mechanical properties at Acetone
addition of 5wt%. Extra amounts of Acetone addition degrade the results. The
mechanical properties, fracture morphology and FTIR spectra shows more
aggressive effect of the Acetone compared with Toluene as solven