Mosab Kaseem | Yeungnam University (original) (raw)

Papers by Mosab Kaseem

Properties modification by blending polymers has been an area of immense interest. In this work, ... more Properties modification by blending polymers has been an area of immense interest. In this work, rheological and mechanical properties of poly(lactic acid)/polystyrene (PLA/PS) blends were investigated. PLA/PS blends in different ratios were prepared using a laboratory scale single screw extruder to obtain (3 mm) granules. Rheological properties were studied using a capillary rheometer and the Bagley's correction was performed. True shear rate (c r), true shear stress (s r), and true viscosity (g r) were determined, the relationship between true viscosity and (1/T) was studied for PLA70 blend and the flow activation energy at a constant shear stress (E s) and a constant shear rate (E c) was determined. The mechanical property measurements were performed at room temperature. Stress at break and strain at break were determined. The results showed that PLA/PS blend exhibited a typical shear-thinning behavior over the range of the studied shear rates, and the viscosity of the blend decreased with increasing PLA content. Also it was found that no equal-viscosity temperature exists between PLA and PS. The mechanical results showed immiscibility between PLA and PS in the blend.

Poly(lactic acid) (PLA) was melt blended with polypropylene (PP) with the aim of replacing commod... more Poly(lactic acid) (PLA) was melt blended with polypropylene (PP) with the aim of replacing commodity polymers in future applications. Since cost of PLA is quite high, it is not economically feasible to use it alone for day to day use as a packaging material without blending. This paper reports the preparation of poly (lactic acid)/polypropylene polymer blends (PLA/PP) using a laboratory scale single screw extruder. Rheolog-ical and mechanical properties of the prepared blends were determined. The rheological experiments were carried out on a capillary rheometer, the effect of shear rate, temperature and PLA content on the flow activation energy and true viscosity of the blends were described. Mechanical properties of the blends were investigated on dog bone-shaped samples obtained by injection molding; tensile tests were performed using Testometric M350-10KN. The effect of PLA content on Young's modulus, strain at break and stress at break of the blends were described. The rheological results showed that the true viscosity of the blends is between that of the pure polymers, whereas the flow activation energy of the blends is less than that of the pure polymers. The mechanical results showed incompatibility between PLA and PP in the blend.

In this work, rheological properties of poly(lactic acid) (PLA), low density polyethylene (LDPE) ... more In this work, rheological properties of poly(lactic acid) (PLA), low density polyethylene (LDPE) polymer blends were investigated in the molten state. The experiments were carried on a capillary rheometer. The effect of shear stress, temperature and blending ratio on the flow activation energy at a constant shear stress and melt viscosity of the blends are described. The results showed that the PLA/LDPE polymer blends are pseudo plastic in nature, where there viscosity decreases with increasing shear stress. Also it was found the melt viscosity of the blends decreases with increasing PLA content in the blend.

A continued increase in the use of plastics has led to an increasing amount of plastics ending up... more A continued increase in the use of plastics has led to an increasing amount of plastics ending up in the waste stream; and the increasing cost of landfill disposal and public interest in support of recycling has meant that plastics recycling must increase. In this work, the effect of multiple extrusion and injection of poly(lactic acid)/poly-styrene polymer blend (PLA/PS) on its rheological and mechanical properties is presented. Rheological properties were studied using a capillary rheometer, apparent shear rate (c a), apparent shear stress (s a), apparent viscosity (g a), and flow activation energy were determined. The mechanical properties of the blend were investigated on dog bone-shaped samples obtained by injection molding, tensile tests were performed, stress at break, strain at break, and Young's modulus were determined. The results showed that the apparent viscosity of PLA/PS blend decreases monotonously with increasing the processing number. Also it was found that stress and strain at break of the blend decrease sharply after two processing cycles, whereas the processing number has a little effect on Young's modulus.

The aim of this review is to discuss the recent developments in thermoplastic starch blends. Star... more The aim of this review is to discuss the recent developments in thermoplastic starch blends. Starch has been considered as an excellent candidate to partially substitute synthetic polymer in packaging, agricul tural mulch and other low cost applications. Recently, the starch granules were plasticized using different plasticizers under heating and shearing, giving rise to a continues phase in the form of a viscous melt which can be processed using traditional plastic processing techniques, such as injection molding and extrusion. This kind of starch composites is called thermoplastic starch. Unfortunately, thermoplastic starch presents some drawbacks, such as low degradation temperatures, which make it difficult to process, poor mechanical properties and high water susceptibility. Much work has been carried out to overcome these drawbacks, including the combination of thermoplastic starch with other polymers, aiming at lowering the cost and enhancing the biodegradability of the final product.

In this work, blends of acrylonitrile–butadiene–styrene (ABS) and thermoplastic starch (TPS) were... more In this work, blends of acrylonitrile–butadiene–styrene (ABS) and thermoplastic starch (TPS) were prepared by using a single screw extruder (SSE), the starch was plasticized in the single screw extruder by using glycerol as a plasticizer. The blends were characterized by studying rheological and mechanical properties. The rheological results indicated that ABS/TPS blend melts were pseudo plastic and exhibited shear–thinning behavior, and the viscosity of the blend decreased with increasing glycerol content. Also the values of flow activation energy at a constant shear stress (E τ) of ABS 1 /TPS 25G blend were determined, and it was found that E τ increased with increasing shear stress. Die swell measurements of the blend showed that die swell ratio increases with increasing shear stress and glycerol content in the blend, while it decreases with increasing L/R. Mechanical results showed that, the values of stress at break and strain at break decreased with increasing TPS content in the blend, which was attributed to the immiscibility between TPS and ABS.

Binary and ternary blends of poly(lactic acid) (PLA), polystyrene (PS) and acrylonitrile-butadien... more Binary and ternary blends of poly(lactic acid) (PLA), polystyrene (PS) and acrylonitrile-butadiene-styrene (ABS) were prepared using a one-step extrusion process. Rheological and mechanical properties of the prepared blends were determined. Rheological properties were studied using a capillary rheometer, shear rate, shear stress, non-Newtonian index, shear viscosity and flow activation energy were determined. Mechanical properties were studied in term of tensile properties, stress at break, strain at break, and Young's modulus was determined. The effect of the composition on the rheological and mechanical properties was investigated. The results show that the ternary blend exhibits shear-thinning behavior over the range of the studied shear rates where the true shear viscosity of the blend decreases with increasing true shear rate, also it was found that the true viscosity of the blend decreases with increasing ABS content. The mechanical results showed that, in the most cases, the stress at break and the Young's modulus improved by the addition of ABS.

Starch as an inexpensive and renewable source has been used as a filler for environmentally frien... more Starch as an inexpensive and renewable source has been used as a filler for environmentally friendly plastics for about two decades. In order to improve the compatibility between hydrophilic starch granules and hydrophobic polypropylene (PP), glycerol used as a plasticizer for starch to enhance the dispersion and the interfacial affinity in thermoplastic starch (TPS)/PP blend. In this study, PP was melt blended with thermoplastic starch (TPS) using a single screw extrusion process and molded using injection molding process to investigate the rheological and mechanical properties of these blends. TPS viscosity measurements were performed on the single screw extruder. Rheological properties were studied using a capillary rheometer and the Bagley's correction was performed. Mechanical analysis (stress– strain) was performed using Testometric M350-10KN. The rheological properties showed that the viscosity of TPS decreases with increasing glycerol content in TPS. Also, it was found that PP/TPS blends are pseudo plastic in nature and the flow activation energy of the blends is greater than that of PP. Mechanical results showed that strain at break of the blends is lower than that of PP, whereas the Young's modulus of the blends is higher than that of PP.

Starch as an inexpensive and renewable source has been used as a filler for environmental friendl... more Starch as an inexpensive and renewable source has been used as a filler for environmental friendly plastics for about two decades. In this study, glycerol was used as a plasticizer for starch to enhance the dispersion and the interfacial affinity in thermoplastic starch (TPS)/ polybutene-1(PB-1) blend. PB-1 was melt blended with TPS using a single screw extrusion process and molded using injection molding process to investigate the rheological and mechanical properties of these blends. Rheological properties were studied using a capillary rheometer, and the Bag-ley's correction was performed. Mechanical analysis (stress– strain curves) was performed using Testometric M350-10 kN. The rheological properties showed that the melt viscosity of the blend is less than that of PB-1, and the flow activation energy at a constant shear stress of the blend increases with increasing glycerol content in the blend. The mechanical experiments showed that both stress and strain at break of the blends are less than that of PB-1, whereas the Young's modulus of the most blends is higher than that of PB-1 which confirms the filling role of TPS in the blend.

In this work, rheological and mechanical properties of acrylonitrile–butadiene–styrene/corn starc... more In this work, rheological and mechanical properties of acrylonitrile–butadiene–styrene/corn starch composites (ABS/starch) were studied. The composites were prepared using a laboratory-scale, single-screw extruder. Rheological properties were determined using the single-screw extruder, apparent shear rate (c a), apparent shear stress (s a), apparent viscosity (g a), non-Newtonian index (n), and flow activation energy at a constant shear rate (E c) and constant shear stress (E s). Mechanical properties in terms of tensile tests were performed using Testometric M350-10KN, stress at break, strain at break, and Young's modulus were determined. Rheological results showed that the composites are pseudo plastic in behavior, and the apparent viscosity of the composites increases with increasing starch content above the additive rule, which indicates a partial compatibility in the composite. It was also found that the flow activation energy of the composite increases with increasing starch content. The mechanical results showed that the strain at break of the composite decreases sharply by the presence of starch, whereas the Young's modulus increases with increasing starch content.

Investigations have been made on the rheological and die swell behaviors of thermoplastic starch/... more Investigations have been made on the rheological and die swell behaviors of thermoplastic starch/acrylonitrile-butadiene-styrene (ABS/TPS) blends. The experimental were carried out on a capillary rheometer. Real viscosity, real shear stress, real shear rate, power law index, viscous activation energy at a constant shear stress (E τ) and die swell ratio were determined. The results showed that the blend is a pseudo plastic material, and the real viscosity of the blend decreases with increasing both of shear rate and glycerol content. Also it was found that ABS 70 /TPS 35G has the lowest value of E τ. Die swell measurements showed that die swell ratio increases with increasing shear stress and glycerol content in the blend, while it decreases with increasing L/R.

A series of blends of Acrylonitrile-Butadiene-Styrene (ABS) and Polycarbonate (PC) and another se... more A series of blends of Acrylonitrile-Butadiene-Styrene (ABS) and Polycarbonate (PC) and another series of polyvinylidene fluoride, PVDF, and low density polyethylene, LDPE, were prepared and characterized for some of their rheological properties. The blends of a series were prepared by mixing the components, with different weight % composition, in a molten state using Brabender Plastograph. Visco-elastic parameters were measured using the capillary rheometer (Melt Index 3/80). Die-swelling rate, (B), was determined for different composition samples and correlated with the end pressure drop, (Pend), the end correction, (e), the apparent shear rate, (a), the apparent shear stress, (a), and the length-radius ratio, (L/R). The effects of blending composition on the die-swell rate, (B), the end correction, (e), and the shear strain, (SR) were also studied for the prepared series of blends.

In this work, the rheological properties of thermoplastic starch (TPS) were determined using a la... more In this work, the rheological properties of thermoplastic starch (TPS) were determined using a laboratory scale single screw extruder at different temperatures (110, 130, and 140 °C) and speeds (10, 15, 20, 25, 30, and 35 RPM). Glycerol was used as a plasticizer for preparing TPS. Apparent shear rate (g Á a), apparent shear stress (t a), apparent shear viscosity (η a) and flow activation energy at a constant shear rate (E γ) were determined. The results showed that TPS melts were pseudo plastic (n<1) and the shear viscosity decreases with increasing shear rate at different temperatures. Also it was found that that shear viscosity of TPS decreases with increasing glycerol content in TPS, according to the values of flow activation energy at a constant shear rate, TPS25 was more sensitive to processing temperature.

Polymer recycling is a way to reduce environmental problems caused by polymeric waste accumulatio... more Polymer recycling is a way to reduce environmental problems caused by polymeric waste accumulation generated from day-today applications of polymer materials such packaging and construction. The recycling of polymeric waste helps to conserve natural resource because the most of polymer materials are made from oil and gas. This paper reviews the recent progress on recycling of polymeric waste form some traditional polymers and their systems (blends and composites) such as polyethylene (PE), polypropylene (PP), and polystyrene (PS), and introduces the mechanical and chemical recycling concepts. In addition, the effect of mechanical recycling on properties including the mechanical, thermal, rheological and processing properties of the recycled materials is highlighted in the present paper.

The influence of acrylonitrile–butadiene–styrene (ABS) copolymer content on the properties of pol... more The influence of acrylonitrile–butadiene–styrene (ABS) copolymer content on the properties of polylactic acid (PLA)/low density polyethylene (LDPE) blend (50/50) was investigated in the present paper. The blend (PLA/LDPE/ABS) was prepared in different ratios using a laboratory scale single screw extruder. The prepared blends were characterized in terms of rheological and mechanical properties. Rheological properties were studied using a capillary rheometer, and the Bagley's correction was performed. Shear rate (γ r), shear stress (τ r), shear viscosity (η r), and non-Newtonian index (n) were determined. The relationship between shear viscosity and temperature was also studied, and the flow activation energy at a constant shear rate (E γ) was determined. The mechanical properties of the blends were investigated on dog-bone-shaped samples obtained by an injection molding machine. The tensile tests were performed using Testometric M350-10KN, and the stress at break, strain at break, and Young's modulus were determined. Rheological properties revealed that the blend exhibited shear-thinning behavior over the range of the studied shear rates, and the viscosity of the blend increased as the ABS content increased, whereas the flow activation energy decreased. Based on the mechanical properties determined for the prepared blends, it was found that no relation between ABS content and stress at break of the blend was regarded, whereas Young's modulus was significantly improved by the addition of ABS.

Biodegradable polymers belong to a family of polymer materials that found applications ranged fro... more Biodegradable polymers belong to a family of polymer materials that found applications ranged from medical applications including tissue engineering, wound management, drugs delivery, and orthopedic devices, to packaging and films applications. For broadening their potential applications, biodegradable polymers are modified utilizing several methods such as blending and composites forming, which lead to new materials with unique properties including high performance, low cost, and good processability. This paper reviews the recent information about the morphology of blends consisting of both biodegradable and non biodegradable polymers and associated mechanical, rheological, and thermal properties of these systems as well as their degradation behavior. In addition, the mechanical performance of composites based on biode gradable polymers is described.

The aim of this work is to study the rheological properties of PVDF/LDPE blends in the molten sta... more The aim of this work is to study the rheological properties of PVDF/LDPE blends in the molten state, in relation to shear rate, shear stress and temperature. Blends of LDPE and PVDF at different compo sitions, namely PVDF/LDPE = 0/100, 30/70, 50/50, 70/30, 100/0 were realized. The blends were prepared by using brabender plastograph and measurements were carried out by using capillary rheometer. For study ing the viscous properties non Newtonian index n, true viscosity η and the flow activation energy E were determined. The melt elasticity has been studied in term of die swell ratio B. The results show that PVDF/LDPE blends behave in pseudo plastic manner (n < 1), plots of true viscosity versus blending ratio go through a minimum nearly at blending ratio (50/50), and the flow activation energy decreases with increasing shear rate at the wall γ but it increases with increasing true shear stress τ. The results of die swell ratio show that, B increases linearly with increasing true shear stress τ, while B decreases with increasing L/R. It was also found that a maximum of elastic properties is observed at certain blending ratio. This phenomenon can be attributed to the amount of elastic deformation energy stored in the melt flow and its transition due to the viscoelastic difference between the two phases.

Polylactic acid (PLA), one of the well-known biodegradable polyesters, has been studied extensive... more Polylactic acid (PLA), one of the well-known biodegradable polyesters, has been studied extensively for tissue engineering and drug delivery systems, and it was also used widely in human medicine. A new method to synthesize PLA (ring-opening polymerization), which allowed the economical production of a high molecular weight PLA polymer, broadened its applications, and this processing would be a potential substitute for petroleum-based products. This review described the principles of the polymerization reactions of PLA and, then, outlined the various materials properties affecting the performance of PLA polymer, such as rheological, mechanical, thermal, and barrier properties as well as the processing technologies which were used to fabricate products based on PLA. In addition, the biodegradation processes of products which were shaped from PLA were discussed and reviewed. The potential applications of PLA in the medical fields, such as tissue engineering, wound management, drugs delivery, and orthopedic devices, were also highlighted.

The effect of sodium benzoate (NaBz) in an electrolyte on the corrosion behavior of a 6061 Al all... more The effect of sodium benzoate (NaBz) in an electrolyte on the corrosion behavior of a 6061 Al alloy coated by plasma electrolytic oxidation (PEO) was investigated. For this purpose, a PEO coating was performed on the present sample under alternating current conditions in an alkaline–aluminate electrolyte with and without NaBz. Regardless of the addition of NaBz, the microstructural observation showed that the coating layers consisted of outer and inner layers. When the alloy was coated in the electrolyte with NaBz, a higher fraction of α-Al 2 O 3 was found in the coating film as compared to the sample coated in the electrolyte without NaBz. In addition, the coating of the sample processed in the electrolyte with NaBz became dense, which resulted in better corrosion resistance than the coating without NaBz. The potentiodynamic polarization test showed that the coating layer formed on the electrolyte with NaBz exhibited superior corrosion resistance to that without NaBz. The corrosion behavior of the PEO-coated sample could be explained using the equivalent circuit model.

Differential speed rolling (DSR) was used to deform AZ31 Mg alloy samples at the two rolling temp... more Differential speed rolling (DSR) was used to deform AZ31 Mg alloy samples at the two rolling temperatures of 473 and 573 K so as to investigate the effects of temperature on the microstructure and plastic anisotropy. The anisotropies in the mechanical properties of the deformed samples were examined by tension tests with respect to three directions (0°, 45°, and 90°) from the DSR deformation direction. A homogeneous and equiaxed microstructure with a mean grain size of ∼14 μm was achieved after DSR deformation at 573 K. Thus, anisotropic behaviour in the mechanical properties was mostly observed in the samples processed by DSR at 473 K. The maximum strength was observed in the 90° direction, and the elongation in the 45° direction was higher than those in other directions. A good combination of high elongation and strength together with the homogenous microstructure was attained on the sample deformed at 573 K.