Experimental Characterization of the Tensile Behavior of Microcellular Polycarbonate Foams

1994 ◽  
Vol 116 (4) ◽  
pp. 439-445 ◽  
Author(s):  
Vipin Kumar ◽  
Michael VanderWel ◽  
John Weller ◽  
Karl A. Seeler

Novel polycarbonate (PC) foams with bubbles on the order of 10 μm and cell nucleation densities between 1 and 10 billion cells per cubic centimeter of foam have been produced using carbon dioxide as the blowing agent. The size and number of bubbles can be controlled to produce a wide range of foam densities. This paper presents the results of an experimental study of the tensile behavior of these unique microcellular foams. It was found that the tensile strength of microcellular PC foams is proportional to the foam density. The strength is less than that predicted by the rule of mixtures, suggesting that the microcellular structure is inefficient in carrying the tensile load. The saturation of PC by CO2 was found to reduce the tensile strength of the virgin material by approximately 20 percent. This showed that the sorption of a very high concentration of gas molecules by the polymer must be considered when characterizing and modelling the microcellular foam mechanical properties. The relative tensile modulus of microcellular foam was found to increase as the square of the foam’s relative density over the range of densities explored.

2019 ◽  
Vol 25 ◽  
pp. 22-31 ◽  
Author(s):  
Farhana Islam ◽  
M. Naimul Islam ◽  
Shahirin Shahida ◽  
Harun Ar Rashid ◽  
Nanda Karmaker ◽  
...  

Jute fabrics reinforced Unsaturated Polyester Resin (UPR)-based composites were prepared by conventional hand lay-up technique. Different proportions (5 to 50% by weight) of fibre content was used in preparation of the composite. Tensile Strength (TS), Tensile Modulus (TM), Bending Modulus (BM), Bending Strength (BS), Impact Strength (IS) of the fabricated composites were studied. Upon each addition of fiber content in the matrix, mechanical properties of the composites were increased. The Tensile Strength (TS) of the 5% and 50% fiber reinforced composites was 18 MPa and 42 MPa respectively. Scanning Electron Microscopy (SEM) showed interfacial properties of the composites and it was revealed that the bond between fiber and matrix was excellent.


1989 ◽  
Vol 4 (6) ◽  
pp. 1339-1346 ◽  
Author(s):  
C. T. Ho ◽  
D. D. L. Chung

Unidirectional and continuous carbon fiber tin-matrix composites were used for the packaging of the high-temperature superconductor YBa2Cu3O7–δ by diffusion bonding at 170 °C and 500 psi. Tin served as the adhesive and to increase the ductility, the normal-state electrical conductivity, and the thermal conductivity. Carbon fibers served to increase the strength and the modulus, both in tension along the fiber direction and in compression perpendicular to the fiber layers, though they decreased the strength in compression along the fiber direction. Carbon fibers also served to increase the thermal conductivity and the thermal fatigue resistance. At 24 vol. % fibers, the tensile strength was approximately equal to the compressive strength perpendicular to the fiber layers. With further increase of the fiber content, the tensile strength exceeded the compressive strength perpendicular to the fiber layers, reaching 134 MPa at 31 vol. % fibers. For fiber contents less than 30 vol. %, the compressive ductility perpendicular to the fiber layers exceeded that of the plain superconductor. At 30 vol. % fibers, the tensile modulus reached 15 GPa at room temperature and 27 GPa at 77 K. The tensile load was essentially sustained by the carbon fibers and the superconducting behavior was maintained after tension almost to the point of tensile fracture. Neither Tc nor Jc was affected by the composite processing.


2020 ◽  
Vol 32 (9) ◽  
pp. 1043-1051
Author(s):  
Lu Kuang ◽  
Wei-Hong Wei ◽  
Xiao-Yan Sang ◽  
Yang Pan ◽  
Cheng Song

1,4-Bis(3,4-dicarboxybenzoyl)benzene dianhydride, an aromatic bis(ketone anhydride) monomer, was synthesized by the Friedel–Crafts reaction of terephthaloyl dichloride and o-xylene, followed by the oxidation of the intermediate tetramethylated compound and cyclodehydration of the resulting tetraacid. A series of new poly(diketone imide)s (PDKIs) were prepared from this dianhydride with various aromatic diamines via a conventional two-stage process that included ring-opening polyaddition to form the poly(amic acid)s followed by thermal or chemical imidization. Most of the PDKIs through chemical imidization were soluble in aprotic amide solvents, such as N, N-dimethylacetamide, N-methyl-2-pyrrolidone, m-cresol, and so on. The resulting PDKIs had good thermal property with the glass transition temperature of 203–275°C, the temperature at 5% weight loss of 500–539°C, and the residue of 51–60% at 800°C in nitrogen. Additionally, strong and flexible PDKI films obtained by thermal imidization exhibited outstanding mechanical property with the tensile strength of 88.8–158.5 MPa, tensile modulus of 1.9–3.5 GPa, and elongation at breakage of 7–21%.


2012 ◽  
Vol 525-526 ◽  
pp. 65-68
Author(s):  
Hitoshi Takagi ◽  
Yuji Hagiwara ◽  
Antonio Norio Nakagaito

This paper reports the microscopic fracture behavior of natural fiber-reinforced green composites. The acoustic emission (AE) method of nondestructive and real-time testing was applied to detect small-scale energy release phenomena during tensile deformation of the green composites. The unidirectional abaca fiber was embedded in a starch-based biodegradable resin matrix. Two kinds of pre-damaged abaca fibers as well as as-received (i.e. undamaged) fiber were used to examine the effect of the pre-damaged abaca fiber on the overall fracture behavior of the unidirectional green composites. In the case of the green composites reinforced with as-received abaca fiber, both of the tensile strength and fracture strain were relatively high. In the case of the green composites reinforced with pre-damaged abaca fiber, however, showed relatively smaller tensile strength and fracture strain. In addition, a wide range of amplitude AE events were measured during the tensile deformation. This tendency was enhanced in the composites reinforced with heavily damaged abaca fiber. The experimental results showed that the AE activity in the early deformation stage was associated with such the microscopic fracture of pre-damaged abaca fibers.


2021 ◽  
Vol 34 ◽  
pp. 149-156
Author(s):  
Nik N. Nasri ◽  
Nazmi M. Nawi ◽  
Azhari S. Baharuddin ◽  
Saripa M. Lazim

The potential use of natural fibre extracted from oil palm empty fruit bunches has gained wide attention among researchers. This natural fibre comes from fibrous strands which form fibre bundle after shredding process at a mill. The measurement of tensile properties is important to understand the mechanical performance of this fibre bundle. This study was undertaken to determine the tensile properties of the fibre bundle from oil palm empty fruit bunch (OPEFB). Fibrous strands of the OPEFB extracted from shredded empty fruit bunches were twisted to form fibre bundle specimens at different diameters varying from 1 to 5 mm. The tensile properties measured in this study including tensile strength, tensile load and tensile modulus. The measurements were performed using Instron Universal Test Machine (IUTM) model 5000. From the results, it was found that the specimens at 1 and 5 mm in diameter required 71.25 and 429.68 N of the tensile load to break, respectively. The specimen with 1 mm in diameter recorded the highest tensile strength of 90.72 MPa while the specimen with 5 mm in diameter recorded only 21.88 MPa. The highest tensile modulus with value of 662.50 MPa was obtained from the specimen with 1 mm in diameter while the specimen with 5 mm in diameter had the tensile modulus value of 157.47 MPa. It was also found that the tensile strength and tensile modulus decreased when the diameter of the specimens increased. The findings reported in this study can serve as an engineering basis for the design specification in the development of the future in-silo composting machine.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
M. Balasubramanian ◽  
Thozhuvur Govindaraman Loganathan ◽  
R. Srimath

Purpose The purpose of this study is to understand the behavior of hybrid bio-composites under varied applications. Design/methodology/approach Fabrication methods and material characterization of various hybrid bio-composites are analyzed by studying the tensile, impact, flexural and hardness of the same. The natural fiber is a manufactured group of assembly of big or short bundles of fiber to produce one or more layers of flat sheets. The natural fiber-reinforced composite materials offer a wide range of properties that are suitable for many engineering-related fields like aerospace, automotive areas. The main characteristics of natural fiber composites are durability, low cost, low weight, high specific strength and equally good mechanical properties. Findings The tensile properties like tensile strength and tensile modulus of flax/hemp/sisal/Coir/Palmyra fiber-reinforced composites are majorly dependent on the chemical treatment and catalyst usage with fiber. The flexural properties of flax/hemp/sisal/coir/Palmyra are greatly dependent on fiber orientation and fiber length. Impact properties of flax/hemp/sisal/coir/Palmyra are depended on the fiber content, composition and orientation of various fibers. Originality/value This study is a review of various research work done on the natural fiber bio-composites exhibiting the factors to be considered for specific load conditions.


2018 ◽  
Vol 213 ◽  
pp. 03001 ◽  
Author(s):  
Ruth R. Aquino ◽  
Marvin S. Tolentino ◽  
Niel Karl G. Arcamo ◽  
John Patrick N. Gara ◽  
Blessie A. Basilia

Membrane technology is widely used in many separation processes because of its multi-disciplinary characteristics. One of the techniques that is used in the fabrication of membranes is the electrospinning process which can create nanofibers from a very wide range of polymeric materials. In this study, electrospun nanostructured fibrous composite membranes of polysulfone (PSU), commercial halloysite (COM-HAL), and Philippine halloysite (PH-HAL) were synthesized. The concentrations of COM-HAL and PH-HAL were both varied from 0.5%, 1%, and 2%. The FTIR results showed that there were changes in the intensity of the PSU-IR spectra which confirmed the presence of COM-HAL and PH-HAL in the synthesized membranes. The SEM revealed that nanofibers can be successfully produced by the addition of LiCl salt in PSU with varying HAL concentrations. Also, it was observed that the addition of HAL with varying concentrations have no significant effect on wettability due to the strong hydrophobic character of the PSU membrane. Moreover, it was found from the analysis of mechanical properties that the tensile strength of the membranes weakened by the addition of HAL due to its weak interaction with PSU.


2017 ◽  
Vol 753 ◽  
pp. 39-43
Author(s):  
Rittichai Sangkatip ◽  
Wipoo Sriseubsai ◽  
Kunlanan Kiatkittipong

Titanate Ribbon (Na2Ti3O7) used in ABS plastic was synthesized to study the mechanical properties and to conduct test on the E-coli bacteria inhibition performance. The polymer blends of ABS/Na2Ti3O7 by Na2Ti3O7, was synthesized through alkaline hydrothermal reaction with 0.5 grams of titanium dioxide as a precursor with 20 ml. of sodium hydroxide (NaOH) at the concentration of 10 molar under the alkalinity at 200 ° c for 24 hours. The study on the microstructure by scanning electron microscope revealed that the Layered structure was shaped as a complete ribbon. The mechanical testing activities on the E-coli bacteria inhibition polymer mixed ABS/Na2Ti3O7; it was found that the mechanical properties for ABS/Na2Ti3O7, The results showed that tensile modulus and tensile strength of blending Na2Ti3O7 at 0.5 %wt was the highest. The result showed that E.coli could reduce up to 66.01%.


2013 ◽  
Vol 814 ◽  
pp. 230-234
Author(s):  
Maria Silvia Pernevan ◽  
Liviu Marşavina ◽  
Ioan Pernevan ◽  
Cecilia Sîrghie ◽  
Mihaela Popescu

The paper analyzes the tensile behavior of some new biocomposite materials based on polypropylene reinforced with hemp shives for different volume fractions and sizes. The aim of this study is to make a comparison between the tensile properties of these materials and to determine in which way the values of the tensile strength and tensile modulus are influenced by the volume fraction and dimensions of the reinforcement elements. The analyzed materials are new materials based on renewable and recyclable resources and from this point of view these materials have a less harmful impact on the environment compared to the conventional composites. By analyzing the tensile properties of polyproylene based biocomposites reinforced with hemp shives it can be observed in which way these materials could replace conventional materials in various fields of applications.


2021 ◽  
pp. 109963622110204
Author(s):  
Hui Li ◽  
Wulong Zhang ◽  
Huisu Chen ◽  
Yudong Han ◽  
Jian Zhang ◽  
...  

Tensile behavior of concrete canvas (CC) mainly depends on the geometric patterns of 3D spacer fabric. A lattice model is proposed to model the three-dimensional structure of CC to investigate the influence of geometric patterns of 3D spacer fabric on the tensile behavior of CC. The stress intensity factor is also applied into the lattice model to study the crack development of CC subjected to tensile load. The simulation results are compared to the experiments to verify the model. Finally, the influence of geometric pattern of outer layer and spacer yarns on tensile behavior of CC are simulated based on our proposed lattice model. The results indicate that the tensile strength of CC increases as the loop unit size of outer surface decreases or the amount of spacer yarns increases; the tensile strength of CC with rhombus loop unit of outer surface layer is higher than that of CC with rectangle loop unit. The tensile strength of CC significantly increases with the increasing inclination angle of spacer yarns in 3D spacer fabric. Furthermore, CC specimens subjected to uni-axial tensile exhibit a multi-cracking behavior, the average crack spacing of specimen decreases with the decreasing inclination angle of spacer yarns in tensile direction.


Sign in / Sign up

Export Citation Format

Share Document