Polypropylene structural foams: Measurements of the core, skin, and overall mechanical properties with evaluation of predictive models

2016 ◽  
Vol 53 (1) ◽  
pp. 25-44 ◽  
Author(s):  
Tarik Sadik ◽  
Caroline Pillon ◽  
Christian Carrot ◽  
José A Reglero Ruiz ◽  
Michel Vincent ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Poisson’S Ratio ◽  
Flexural Modulus ◽  
Tensile Modulus ◽  
Poisson's Ratio ◽  
Injection Molding Process ◽  
Mixing Rule ◽  
Molding Process ◽  
Plane Shear ◽  
The Core

Relationships for the prediction of various linear mechanical properties of polymeric sandwich foams obtained in injection processes were studied in comparison with shear, tensile, and flexural tests. The samples were obtained by a core-back foam injection molding process that enables one to obtain sandwich materials with dense skins and a foamed core as revealed by the morphological analysis. Tensile, shear, and flexural moduli were investigated for the skin, the core, and the overall foamed structure. In addition, the Poisson’s ratio of the skin was also determined. The core properties were specifically analyzed by machining the samples and removing the skins. Tensile and shear properties of the core can be well described by the Moore equation. The tensile modulus can be calculated by a linear mixing rule with the moduli of the skin and of the core in relation to the thickness of the layers. Shear and flexural moduli are described by a linear mixing rule on the rigidity in agreement with the mechanics of beams. Tensile modulus, out-of-plane shear modulus, and flexural modulus can finally be predicted by the knowledge of only very few data, namely the tensile modulus and Poisson’s ratio of the matrix, the void fraction, and thickness of the core. The equations were proved to be physically meaningful and consistent with each other.

scholarly journals Calcium Carbonate Particles Filled Homopolymer Polypropylene at Different Loading Levels: Mechanical Properties Characterization and Materials Failure Analysis

2021 ◽  
Vol 5 (11) ◽  
pp. 302
Author(s):  
Yucheng Peng ◽  
Munkaila Musah ◽  
Brian Via ◽  
Xueqi Wang
Keyword(s):  
Mechanical Properties ◽  
Calcium Carbonate ◽  
Impact Strength ◽  
Flexural Modulus ◽  
Fracture Initiation ◽  
Injection Molding Process ◽  
Specimen Preparation ◽  
Molding Process ◽  
Materials Failure ◽  
Mechanical Properties Characterization

Calcium carbonate (CaCO3) particles have been widely used in filling thermoplastics for different applications in automotive, packaging, and construction. No agreement has been reached in the research community regarding the function of CaCO3 for enhancing toughness of homopolymer polypropylene (HPP). This study was to understand the effect of different loading levels of CaCO3 on HPP toughness, including notched and unnotched impact strength. A batch mixer was used to thermally compound CaCO3 particles with HPP at loading levels of 10, 20, 30, 40, and 50 wt.%, followed by specimen preparation using an injection molding process. The mechanical properties of the composites, including tensile, flexural, and impact were characterized. The results indicated that tensile strengths decreased significantly with increasing loading levels of CaCO3 particles while the tensile and flexural modulus increased significantly with increasing particle loadings. The composite tensile properties changed linearly with increasing CaCO3 loadings. The notched Izod impact strength of the composites was sustained by adding CaCO3 particles up to 40 wt.% while the unnotched impact strength decreased significantly with the addition of CaCO3 particles. Different deformation mechanisms between notched (fracture propagation) and unnotched (fracture initiation and propagation) impact tests were proposed to be the reason.

scholarly journals Effects of Pressurizing Cryogenic Treatments on Physical and Mechanical Properties of Shale Core Samples—An Experimental Study

Gases ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 33-50
Author(s):  
Rayan Khalil ◽  
Hossein Emadi ◽  
Faisal Altawati
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Cryogenic Treatment ◽  
Poisson's Ratio ◽  
The Core ◽  
Core Samples ◽  
Bulk Compressibility ◽  
Core Holder

The technique of cryogenic treatments requires injecting extremely cold fluids such as liquid nitrogen (LN2) into formations to create fractures in addition to connecting pre-existing fracture networks. This study investigated the effects of implementing and pressurizing cryogenic treatment on the physical (porosity and permeability) and mechanical properties (Young’s modulus, Poisson’s ratio, and bulk compressibility) of the Marcellus shale samples. Ten Marcellus core samples were inserted in a core holder and heated to 66 °C using an oven. Then, LN2 (−177 °C) was injected into the samples at approximately 0.14 MPa. Nitrogen was used to pressurize nine samples at injection pressures of 1.38, 2.76, and 4.14 MPa while the tenth core sample was not pressurized. Using a cryogenic pressure transducer and a T-type thermocouple, the pressure and temperature of the core holder were monitored and recorded during the test. The core samples were scanned using a computed tomography (CT) scanner, and their porosities, permeability, and ultrasonic velocities were measured both before and after conducting the cryogenic treatments. The analyses of CT scan results illustrated that conducting cryogenic treatments created new cracks inside all the samples. These cracks increased the pore volume, and as a result, the porosity, permeability, and bulk compressibility of the core samples increased. The creations of the new cracks also resulted in reductions in the compressional and shear velocities of the samples, and as a result, decreasing the Young’s modulus and Poisson’s ratio. Moreover, the results revealed that pressurizing the injected LN2 increased the alterations of aforementioned properties.

scholarly journals Representative volume element based micromechanical modelling of rod shaped glass filled epoxy composites

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Aanchna Sharma ◽  
Yashwant Munde ◽  
Vinod Kushvaha
Keyword(s):  
Representative Volume Element ◽  
Poisson’S Ratio ◽  
Volume Fraction ◽  
Tensile Modulus ◽  
Volume Element ◽  
Poisson's Ratio ◽  
Epoxy Composites ◽  
Micromechanical Modeling ◽  
Representative Volume ◽  
Shaped Glass

AbstractIn this study, Representative Volume Element based micromechanical modeling technique has been implemented to assess the mechanical properties of glass filled epoxy composites. Rod shaped glass fillers having an aspect ratio of 80 were used for preparing the epoxy composite. The three-dimensional unit cell model of representative volume element was prepared with finite element analysis tool ANSYS 19 using the periodic square and hexagonal array with an assumption that there is a perfect bonding between the filler and the epoxy matrix. Results revealed that the tensile modulus increases and Poisson’s ratio decreases with increase in the volume fraction of the filler. To study the effect of filler volume fraction, the pulse echo techniques were used to experimentally measure the tensile modulus and Poisson’s ratio for 5% to 15% volume fraction of the filler. A good agreement was found between the RVE based predicted values and the experimental results.

scholarly journals Improving the mechanical properties of polypropylene composites with coconut shell particles

2021 ◽  
Vol 30 ◽  
pp. 263498332110074
Author(s):  
Henry C Obasi ◽  
Uchechi C Mark ◽  
Udochukwu Mark
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Flexural Modulus ◽  
Filler Particle ◽  
Tensile Modulus ◽  
Coconut Shell ◽  
Polypropylene Composites ◽  
Increase With Increase ◽  
Pp Composites ◽  
Shell Particles

Conventional inorganic fillers are widely used as fillers for polymer-based composites. Though, their processing difficulties and cost have demanded the quest for credible alternatives of organic origin like coconut shell fillers. Dried shells of coconut were burnt, ground, and sifted to sizes of 63, 150, 300, and 425 µm. The ground coconut shell particles (CSP) were used as a filler to prepare polypropylene (PP) composites at filler contents of 0% to 40% via injection melt blending process to produce PP composite sheets. The effect of the filler particle size on the mechanical properties was investigated. The decrease in the size of filler (CSP) was found to improve the yield strength, tensile strength, tensile modulus, flexural strength, flexural modulus, and hardness of PP by 8.5 MPa, 15.75 MPa, 1.72 GPa, 7.5 MPa, 100 MPa, and 10.5 HR for 63 µm at 40%, respectively. However, the elongation at break and modulus of resilience of the PP composites were seen to increase with increase in the filler size. Scanning electron microscope analysis showed that fillers with 63 µm particle size had the best distribution and interaction with the PP matrix resulting in enhanced properties.

The Effect of Heat Treatment on Mechanical Properties of Car Interior Fabric Used for Injection Molding

2012 ◽  
Vol 532-533 ◽  
pp. 234-237
Author(s):  
Wei Lai Chen ◽  
Ding Hong Yi ◽  
Jian Fu Zhang
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
High Temperature ◽  
Injection Molding ◽  
High Temperatures ◽  
Material Properties ◽  
Injection Molding Process ◽  
Molding Process ◽  
Composite Fabrics

The purpose of this paper is to study the effect of high temperature in injection molding process on mechanical properties of the warp-knitted and nonwoven composite fabrics (WNC)used in car interior. Tensile, tearing and peeling properties of WNC fabrics were tested after heat treatment under120, 140,160,180°C respectively. It was found that, after 140°C heat treatment, the breaking and tearing value of these WNC fabrics are lower than others. The results of this study show that this phenomenon is due to the material properties of fabrics. These high temperatures have no much effect on peeling properties of these WNC fabrics. It is concluded that in order to preserve the mechanical properties of these WNC fabrics, the temperature near 140°C should be avoided possibly during injection molding process.

Measurement of Young's Modulus and Poisson's Ratio of Thin Film by Combination of Bulge Test and Nano-Indentation

2008 ◽  
Vol 33-37 ◽  
pp. 969-974 ◽  
Author(s):  
Bong Bu Jung ◽  
Seong Hyun Ko ◽  
Hun Kee Lee ◽  
Hyun Chul Park
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Young’S Modulus ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Applied Pressure ◽  
Indentation Test ◽  
Poisson's Ratio ◽  
Bulge Test ◽  
Nano Indentation

This paper will discuss two different techniques to measure mechanical properties of thin film, bulge test and nano-indentation test. In the bulge test, uniform pressure applies to one side of thin film. Measurement of the membrane deflection as a function of the applied pressure allows one to determine the mechanical properties such as the elastic modulus and the residual stress. Nano-indentation measurements are accomplished by pushing the indenter tip into a sample and then withdrawing it, recording the force required as a function of position. . In this study, modified King’s model can be used to estimate the mechanical properties of the thin film in order to avoid the effect of substrates. Both techniques can be used to determine Young’s modulus or Poisson’s ratio, but in both cases knowledge of the other variables is needed. However, the mathematical relationship between the modulus and Poisson's ratio is different for the two experimental techniques. Hence, achieving agreement between the techniques means that the modulus and Poisson’s ratio and Young’s modulus of thin films can be determined with no a priori knowledge of either.

Measurement of Cement in Situ Stresses and Mechanical Properties Without Cooling or Depressurization

2021 ◽  
Author(s):  
Meng Meng ◽  
Luke Frash ◽  
James Carey ◽  
Wenfeng Li ◽  
Nathan Welch ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Elastic Modulus ◽  
Poisson’S Ratio ◽  
Axial Stress ◽  
Triaxial Compression ◽  
In Situ Measurement ◽  
Poisson's Ratio ◽  
Ambient Conditions

Abstract Accurate characterization of oilwell cement mechanical properties is a prerequisite for maintaining long-term wellbore integrity. The drawback of the most widely used technique is unable to measure the mechanical property under in situ curing environment. We developed a high pressure and high temperature vessel that can hydrate cement under downhole conditions and directly measure its elastic modulus and Poisson's ratio at any interested time point without cooling or depressurization. The equipment has been validated by using water and a reasonable bulk modulus of 2.37 GPa was captured. Neat Class G cement was hydrated in this equipment for seven days under axial stress of 40 MPa, and an in situ measurement in the elastic range shows elastic modulus of 37.3 GPa and Poisson's ratio of 0.15. After that, the specimen was taken out from the vessel, and setted up in the triaxial compression platform. Under a similar confining pressure condition, elastic modulus was 23.6 GPa and Possion's ratio was 0.26. We also measured the properties of cement with the same batch of the slurry but cured under ambient conditions. The elastic modulus was 1.63 GPa, and Poisson's ratio was 0.085. Therefore, we found that the curing condition is significant to cement mechanical property, and the traditional cooling or depressurization method could provide mechanical properties that were quite different (50% difference) from the in situ measurement.

Tribology study of hydroxyapatite (HAp) scaffold blended single based binder via rheology and mechanical properties

2017 ◽  
Vol 69 (3) ◽  
pp. 414-419
Author(s):  
Mimi Azlina Abu Bakar ◽  
Siti Norazlini Abd Aziz ◽  
Muhammad Hussain Ismail
Keyword(s):  
Mechanical Properties ◽  
Injection Molding ◽  
Palm Stearin ◽  
Polymeric Materials ◽  
High Energy ◽  
Single Step ◽  
Injection Molding Process ◽  
Plastic Behavior ◽  
Molding Process ◽  
Content Type

Purpose This paper aims to investigate the vital characteristic of an innovative ceramic injection molding (CIM) process for orthopedic application with controlled porosity and improved tribological and mechanical properties which were affected by complex tribological interactions, whether lubricated like hip implants and other artificial prostheses. The main objective is to maximize the usage of palm stearin as a single based binder as the function of flow properties during injection molding process. Design/methodology/approach The binder used in this present study consists of 100 per cent palm stearin manufactured by Kempas Oil Sdn Bhd and supplied by Vistec Technology Sdn Bhd. The feedstock was prepared by using a Z-blade mixer (Thermo Haake Rheomix OS) and Brabender mixer model R2400. The feedstock prepared was injection molded using a manually operated vertical benchtop machine with an average pressure of about 5-7 bars. The firing step included the temporary holds at intermediate temperatures to burn out organic binders. At this stage, the green molded specimen was de-bound using a single-step wick-debinding method. Findings The maximum content of ceramic material is applied to investigate the efficiencies of net formulation that can be achieved by ceramic materials. The longer the viscosity will change with shear rate, the higher the value of n obtained instead. From the slope of the curves obtained in Figure 3, the value of n for the feedstock was determined to be less than 1, which indicates a pseudoplastic behavior and suitability for the molding process. Moreover, high shear sensitivity is important in producing complex and intrinsic specimens which are leading products in the CIM industry. Originality/value The feedstock containing HAp powder and palm stearin binder was successfully prepared at very low temperature of 70°C, which promoting a required pseudo-plastic behavior during rheological test. The single binder palm stearin should be optimized in other research works carried out, as palm stearin is most preferred compared to other polymeric materials that provided high energy consumption when subjected to the sintering process. Besides the binder is widely available in Malaysia, low cost and harmless effect during debinding process.

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