MECHANICAL PERFORMANCE OF ROTOMOULDED WOLLASTONITE-REINFORCED POLYETHYLENE COMPOSITES

2007 ◽  
Vol 21 (07) ◽  
pp. 1059-1066 ◽  
Author(s):  
XIAOWEN YUAN ◽  
ALLAN J. EASTEAL ◽  
DEBES BHATTACHARYYA

This paper describes the development of a new processing technology for rotational moulding of wollastonite microfibre (WE) reinforced polyethylene (PE). Manufacturing wollastonite-polyethylene composites involved blending, compounding by extrusion, and granulating prior to rotational moulding. The properties of the resulting composites were characterised by tensile and impact strength measurements. The results show that tensile strength increases monotonically with the addition of wollastonite fibres, but impact strength is decreased. In addition, the processability is also decreased after adding more than 12 vol% WE because of increased viscosity. The effects of a coupling agent, maleated polyethylene (MAPE), on the mechanical performance and processability were also investigated. SEM analysis reveals good adhesion between the fibre reinforcements and polyethylene matrix at the fracture surface with the addition of MAPE. It is proposed that fillers with small particles with high aspect ratio (such as wollastonite) provide a large interfacial area between the filler and the polymer matrix, and may influence the mobility of the molecular chains.

2007 ◽  
Vol 334-335 ◽  
pp. 265-268 ◽  
Author(s):  
Xiao Wen Yuan ◽  
Debes Bhattacharyya ◽  
Allan J. Easteal

The usefulness of rotational moulding (rotomoulding) as a polymer processing technique is often limited by the selection of polymers, which in most cases happens to be polyethylene (PE). In the present study, PE polyethylene was blended with wollastonite microfibres and maleated polyethylene (as a coupling agent) with the purpose of developing an improved material for rotational moulding. The incorporation of wollastonite fibres without any coupling agent improved the tensile strength, but showed a reduction in impact strength. As expected, the most significant enhancement due to wollastonite was in the tensile modulus.. The addition of a coupling agent improved both the impact strength and the processability, especially when wollastonite was coated with aminosilane. Scanning electron microscopy revealed good adhesion between the coated fibre reinforcement and the polyethylene matrix at the fracture surface.


Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 890
Author(s):  
Mateusz Barczewski ◽  
Olga Mysiukiewicz ◽  
Aleksander Hejna ◽  
Radosław Biskup ◽  
Joanna Szulc ◽  
...  

In this work, thermally expanded vermiculite (TE-VMT) was surface modified and used as a filler for composites with a polylactide (PLA) matrix. Modification of vermiculite was realized by simultaneous ball milling with the presence of two PLA chain extenders, aromatic carbodiimide (KI), and 4,4’-methylenebis(phenyl isocyanate) (MDI). In addition to analyzing the particle size of the filler subjected to processing, the efficiency of mechanochemical modification was evaluated by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The composites of PLA with three vermiculite types were prepared by melt mixing and subjected to mechanical, thermomechanical, thermal, and structural evaluation. The structure of composites containing a constant amount of the filler (20 wt%) was assessed using FTIR spectroscopy and SEM analysis supplemented by evaluating the final injection-molded samples’ physicochemical properties. Mechanical behavior of the composites was assessed by static tensile test and impact strength hardness measurements. Heat deflection temperature (HDT) test and dynamic thermomechanical analysis (DMTA) were applied to evaluate the influence of the filler addition and its functionalization on thermomechanical properties of PLA-based composites. Thermal properties were assessed by differential scanning calorimetry (DSC), pyrolysis combustion flow calorimetry (PCFC), and thermogravimetric analysis (TGA). The use of filler-reactive chain extenders (CE) made it possible to change the vermiculite structure and obtain an improvement in interfacial adhesion and more favorable filler dispersions in the matrix. This translated into an improvement in impact strength and an increase in thermo-mechanical stability and heat release capacity of composites containing modified vermiculites.


2019 ◽  
Vol 69 (4) ◽  
pp. 313-321
Author(s):  
Xiaoxia Hu ◽  
Zhenghao Chen ◽  
Yang Cao ◽  
Zhangjing Chen ◽  
Shuangbao Zhang ◽  
...  

Abstract The focus of this study was to observe the properties of bamboo plastic composites modified with a self-made modifier, 18 acyl-dopamine (0, 0.25, 0.50, 0.75, 1.00, and 1.25 weight percent [wt%] based on the dry weight of bamboo powder). The effects of the modifier were demonstrated by measures of mechanical properties, water absorption, thermal stability, and scanning electron microscopy (SEM). The results revealed that 18 acyl-dopamine could be used as an effective modifier of bamboo powder/high-density polyethylene composites. When the modifier was increased, the toughness of the composite deteriorated, and the strength and rigidity improved. This indicated that when the dosage became higher, the compatibilization became stronger, and the toughening effect became worse. Based on the experimental data, a small dosage modifier acted as a toughening agent; as the dosage increased to 1.0 wt%, the compatibility began to appear. The modifier reacted with the hydroxyl groups on the surface of the bamboo powder, which caused the bamboo powder to absorb less water, so the thickness expansion rate was lowest at 1.25 wt%. The pyrolysis peak of bamboo powder and plastic showed a tendency to be close to each other, indicating that the interface was improving. Based on the equation of Flynn-Wall-Ozawa, as the dosage of the modifier increased from 0.50 to 1.25 wt%, the apparent activation energy also increased. The SEM analysis showed the binding between bamboo powder and the plastic matrix was strongest when the modifier dosage was 1.25 wt%.


2021 ◽  
Vol 32 ◽  
pp. 85-97
Author(s):  
Gunturu Bujjibabu ◽  
Vemulapalli Chittaranjan Das ◽  
Malkapuram Ramakrishna ◽  
Konduru Nagarjuna

Banana/Coir fiber reinforced polypropylene hybrid composites was formulated by using twin screw extruder and injection molding machine. Specimens were prepared untreated and treated B/C Hybrid composites with 4% and 8% of MA-g-PP to increase its compatibility with the polypropylene matrix. Both the without MA-g-PP and with MA-g-PP B/C hybrid composites was utilized and three levels of B/C fiber loadings 15/5, 10/10 and 5/15 % were used during manufacturing of B/C reinforced polypropylene hybrid composites. In this work mechanical performance (tensile, flexural and impact strengths) of untreated and treated (coupling agent) with 4% and 8% of MA-g-PP B/C fibers reinforced polypropylene hybrid composite have been investigated. Treated with MA-g-PP B/C fibers reinforced specimens explored better mechanical properties compared to untreated B/C fibers reinforced polypropylene hybrid composites. Mechanical tests represents that tensile, flexural and impact strength increases with increase in concentration of coupling agent compared to without coupling agent MA-g-PP hybrid composites . B/C fibers reinforced polymer composites exhibited higher tensile, flexural and impact strength at 5% of Banana fiber, 15% of fiber Coir in the presence of 8% of MA-g-PP compared to 4% of MA-g-PP and untreated hybrid composites. The percentage of water absorption in the B/C fibers reinforced polypropylene hybrid composites resisted due to the presence of coupling agent MA-g-PP and thermogravimetry analysis (TGA) also has done.


2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Wei Kit Chee ◽  
Nor Azowa Ibrahim ◽  
Norhazlin Zainuddin ◽  
Mohd Faizal Abd Rahman ◽  
Buong Woei Chieng

Poly(lactic acid) (PLA)/poly(ε-caprolactone) (PCL) blends were prepared via melt blending technique. Glycidyl methacrylate (GMA) was added as reactive compatibilizer to improve the interfacial adhesion between immiscible phases of PLA and PCL matrices. Tensile test revealed that optimum in elongation at break of approximately 327% achieved when GMA loading was up to 3wt%. Slight drop in tensile strength and tensile modulus at optimum ratio suggested that the blends were tuned to be deformable. Flexural studies showed slight drop in flexural strength and modulus when GMA wt% increases as a result of improved flexibility by finer dispersion of PCL in PLA matrix. Besides, incorporation of GMA in the blends remarkably improved the impact strength. Highest impact strength was achieved (160% compared to pure PLA/PCL blend) when GMA loading was up to 3 wt%. SEM analysis revealed improved interfacial adhesion between PLA/PCL blends in the presence of GMA. Finer dispersion and smooth surface of the specimens were noted as GMA loading increases, indicating that addition of GMA eventually improved the interfacial compatibility of the nonmiscible blend.


1967 ◽  
Vol 40 (3) ◽  
pp. 801-805 ◽  
Author(s):  
Lawrence E. Nielsen

Abstract By the use of simple models of filled plastics, approximate equations are derived for elongation to break in the case of perfect adhesion between the phases and for the tensile strength in the case of no adhesion between the polymer and filler phases. By combining these equations with equations for the modulus (assuming Hookean behavior) all the stress strain properties can be derived, including rough estimates of the impact strength, as a function of filler concentration. The theory predicts a very rapid decrease in elongation to break as filler concentration increases, especially with good adhesion; it is also predicted that the tensile strength of a filled polymer can be greater than that of an unfilled polymer.


Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 787 ◽  
Author(s):  
Janusz W. Sikora ◽  
Ivan Gajdoš ◽  
Andrzej Puszka

The aim of the present work is to investigate the effect of halloysite nanotubes (HNT) on the mechanical properties of low-density polyethylene composites modified by maleic anhydride-grafted PE (PE-graft-MA). Polyethylene nanocomposites were prepared using an injection molding machine, Arburg Allrounder 320 C 500–170; the HNT content was varied at 0 wt %, 2 wt %, 4 wt % and 6 wt %, and the PE-graft-MA content was varied at 5 wt %. The composites were examined for their ultimate tensile stress, strain at ultimate stress, hardness, impact strength, melt flow rate, heat deflection temperature, Vicat softening temperature, crystallinity degree and phase transition temperature. It was found that the addition of halloysite nanotubes to low-density polyethylene (LDPE) led to an increased heat deflection temperature (HDT, up to 47 °C) and ultimate tensile strength (up to 16.00 MPa) while the Vicat softening temperature, strain at ultimate stress, impact strength and hardness of examined specimens slightly decreased. Processing properties of the materials specified by the melt flow rate (MFR) deteriorated almost twice. The results have demonstrated that the nanoparticles can reinforce enhance LDPE at low filler content without any considerable loss of its ductility, but only when halloysite nanotubes are superbly distributed in the polyethylene matrix.


Author(s):  
Naveed Akhtar ◽  
Razzaq Ahmed ◽  
Muhammad Arfan ◽  
Muhammad Noshad Ali

Aluminium chips were re-melted under the molten bath in a gas fired reverberatory furnace and superior quality recycled AA6061-T6 alloy was synthesized. The chips were added 5 to 20% by weight in the recycled alloy. The furnace charge included clean scrap of the same alloy (AA6061) along with the machining chips or tunings of mixed nature. The chips used in this study were mostly generated from lath/bore operations carried on homogenized billets. The fabricated alloy of each heat was characterized for microstructures, mechanical properties and fracture behavior. The results showed that the metallurgical and mechanical performance of the recycled alloy was comparable to the primary alloy. However, SEM analysis of the recycled alloy revealed a sizeable amount of Fe and Si containing intermetallic compounds such as AlFeSi, AlFeMg, and AlSiMg phases.


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