Shore Hardness Tests Research Articles

Study of the Mechanical Properties Re-Processed of Thermoplastic Polymer Composites

This study presents the evaluation of selected mechanical tests of polymer composites which were re-processed. Materials Valox PBT (with 30 % glass fibre) and Celanex® 2004-2 PBT (without filler) and their regranulate were used at tests. The material PBT - regranulate PBT compositions investigated were 100/0, 80/20, 60/40, 30/70 and 0/100. Samples from PBT were prepared by injection molding and their mechanical properties were tested by tensile test and Shore hardness test. The material made from 100% recycled material compared to the baseline had a decrease in tensile strength and Shore hardness value hasn’t changed. Failure of the samples was also observed by SEM. Utilization of regranulate at the production of new moulded parts are important from aspect of reduction plastics waste and pollution abatement of environment.

Comparison for Physical and Mechanical Properties of Dental Rubber Impression Materials

본 연구에서는 OpenFOAM 기반의 부유식 연직판의 파랑 저감 성능 평가 수치해석 모델링을 수행하였다. Waves2FOAM 라이브러리를 기반으로 내부조파에 의한 파랑 생성 및 스폰지층에 의한 소파 기능을 추가로 적용하였다. 이렇게 추가된 조파 및 소파 기능을 먼저 간단한 2차원 해석으로 검증한 후, Briggs et al.(2001)의 규칙파 실험자료 2가지에 대한 수치모델링을 수행하였다. 모델링 결과는 실험자료와 대체로 잘 일치하였으며, Briggs et al.(2001)에 수록된 WAMIT 수치해석 결과보다 더 좋은 결과를 나타내었다.

A study on the irradiated strength and stress evaluation of nuclear graphite material

In the investigative study of the Isotropic Graphite IG-110 of Toyo Tanso, the shore hardness test, compressive test, bending test and fracture toughness test were conducted. The compressive test, the bending test and the fracture toughness test were performed by MTS-810. Test velocity of the compressive and the bending test were 0.5mm/min and the fracture toughness test were 0.1mm/min. The results were compared with manufacturer data of Toyo Tanso. Through irradiation test using HANARO research reactor, hardness and strength of nuclear graphite IG-110 was examined. Strength and hardness of irradiated steel is higher than non-irradiated, but nuclear graphite IG-110 declined unlike steel. To search for characteristic change of nuclear graphite IG-110 under the amounts of neutron, a repeat of the experiment was conducted.

Modeling uniaxial compressive strength of building stones using non-destructive test results as neural networks input parameters

Uniaxial compressive strength value (UCS) is used as a critical input parameter in determining the engineering properties of natural building stones. The purpose of present study was to develop a model to determine the UCS of natural building stones via relatively simple and low-cost mechanical tests with the application of artificial neural networks. For this purpose uniaxial compressive strength, ultrasonic pulse velocities, Schmidt hammer hardness, and Shore hardness tests were performed on 37 different specimens of natural building stones collected from various natural stone processing plants in Turkey. The artificial neural networks (ANNs) approach was utilized for the development of the model that predicts the UCS.The major goal was to develop a model that makes the best prediction with the fewest number of input parameters. Therefore, analyses for verification of the models started with single input parameter and then combinations of two and three input parameters were used. For that purpose, two separate approaches were utilized with seven different sets of analyses in each method. The results of the ANNs models were compared with respect to the results of regression models. The criteria used to evaluate the predictive performances of the models were the coefficient of determination (R2), root mean square error (RMSE), and variance account for (VAF). The results show that the proposed ANNs method could be applied effectively for the prediction of UCS either from one of the input parameters or from their combinations i.e. ultrasonic pulse velocity, Schmidt hammer hardness and Shore hardness.

Synthesis of new polyurethanes from vegetable oil by thiol-ene coupling

Soybean vegetable oil was functionalized in a single step by addition of mercaptan with hydroxyl functions by thermal thiol-ene coupling. The synthesized biobased polyol was analyzed by nuclear magnetic resonance, titrations, size exclusion chromatography, and mass analyses to precisely determine its average functionality, thus allowing the use of the mixture of products without purification. This polyol was added to a prepolymer of 4, 4’-diisocyanate diphenylmethylene (MDI) with a ratio OH/NCO of 1, to synthesize partially bio-based polyurethane by step growth polymerization. The synthesized polyurethane was compared to polyurethane obtained from a commercial polyether polyol polyester, named desmophen 1150. Mixtures of these polyols were made to optimize the properties of the materials obtained. Polymerization was monitored by rheology. Polyurethanes were characterized by thermogravimetric analysis, differential scanning calorimetry, shore hardness, and tensile tests at different temperatures to determine their thermal and mechanical properties. Different materials present the characteristics of soft and ductile elastomers with thermal stability of polyurethanes.

Study of the synthesis and bonding properties of reactive hot‐melt polyurethane adhesive

AbstractReactive hot‐melt polyurethane adhesive (RHMPA) is moisture‐curing polyurethane (PU) adhesive whose main component is an isocyanate‐terminated PU prepolymer that can be cured after application by reaction with ambient moisture. Two series of RHMP‐containing poly(tetramethylene glycol) (PTMG) of different molecular weights and different degrees of polymerization of the hard segment have been successfully synthesized using a two‐step bulk polymerization with 4,4′‐diphenylmethane diisocyanate, PTMG, and 1,4‐butanediol (1,4‐BDO). The structure and basic properties of the RHMPA film have also been characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis, atomic force microscopy, gel permeation chromatography (GPC), shore hardness (A/D), and tensile tests. The results show that the initial decomposition temperature is more than 250°C, and the tensile strength of the RHMPA film was greater than 15 MPa. The adhesive performance of the RHMPA with different hard‐segment content was studied through studies of the single lap‐shear strength and tensile strength of butt joints. The results show a general trend of the bonding strength increases with the hard‐segment content at 25°C. The adhesive performance of RHMPA in different environments was also investigated. It was found that the RHMPA exhibited excellent bonding strength to thermoplastic polyurethane elastomer (TPU) when placed in the fridge at −20°C, hot water at 80°C, 1 M HCl solution (acid) at 25°C, and 1 M NaOH solution (alkaline) at 25°C for 10 h. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Prediction of specific cutting energy for large diameter circular saws during natural stone cutting

Statistical methods re-utilized for the prediction of specific cutting energy values (SEcut) based on the operational variables of block cutters and rock properties. Performance measurements of seven different types of block cutters were applied to six different carbonate rocks and three stone processing plants. Energy consumption of large diameter circular diamond saw block cutters was measured and recorded for a number of sawblade diameters during the cutting process by means of a portable power analyzer. Additionally, rock samples were collected from stone processing plants for laboratory tests. Uniaxial compressive strength, bending strength, Brazilian tensile strength, point load strength, Shore hardness test, Schmidt hammer hardness test, seismic velocity, water absorption at atmospheric pressure, apparent density, open porosity, sawblade diameter, and depth of cut values were used as input parameters in the analysis for the prediction of SEcut. The reliability of the developed model was tested with statistical methods. The SEcut values for carbonate rocks in the stone cutting process can be predicted successfully for large diameter circular saws in natural stone processing by using the model developed here.

Investigating the Mechanical Properties and Drill-ability of Rocks

Drilling is the primitive and common operation in rock excavation industry, starting from exploration to exploitation. Effect of mechanical properties of the formation on drilling operation is a big challenge to mining engineers. The primarily problem is rock drill-ability. The objective of this paper is to correlate the drill-ability of certain rocks with their mechanical properties including Compressive strength, Tensile strength, Schmidt hammer rebound number and Shore Hardness number, in order to establish rate of penetration. This paper contains investigation of both laboratory experiments and Field examination of drilling equipment. Laboratory work includes the determination of various mechanical properties of rock specimen, determined according to ASTM procedure using Universal Testing Machine. Schmidt hammer test conductedon the rock specimen by clamping into the UTM loading platens. Shore hardness test performed on disc specimen carefully prepared for the purpose. The test was conducted as per standard procedure.

Investigating the Mechanical Properties and Drill-ability of Rocks

Drilling is the primitive and common operation in rock excavation industry, starting from exploration to exploitation. Effect of mechanical properties of the formation on drilling operation is a big challenge to mining engineers. The primarily problem is rock drill-ability. The objective of this paper is to correlate the drill-ability of certain rocks with their mechanical properties including Compressive strength, Tensile strength, Schmidt hammer rebound number and Shore Hardness number, in order to establish rate of penetration. This paper contains investigation of both laboratory experiments and Field examination of drilling equipment. Laboratory work includes the determination of various mechanical properties of rock specimen, determined according to ASTM procedure using Universal Testing Machine. Schmidt hammer test conductedon the rock specimen by clamping into the UTM loading platens. Shore hardness test performed on disc specimen carefully prepared for the purpose. The test was conducted as per standard procedure.

Studies on morphology and mechanical properties of dispersing intercalated silane montmorillonite in polypropylene matrix

AbstractWe used a plastograph‐mixer by the twin‐screw mixed method to obtain the standard shaped specimens of polymer‐clay nanocomposites (PCN) to prepare polypropylene (PP)/silane montmorillonite (MMT) nanocomposites pellets, grafting with two kinds of different surfactant—hard grafting agent maleic anhydride (MA) or soft grafting agent thermoplastic polyolefin elastomers (TPO). The chemical structure and polymer morphology of these as‐synthesized PCN specimens were characterized by a wide‐angle powder X‐ray diffraction (XRD) and a scanning electron microscopy (SEM). In addition, we prepared these experimental specimens in order to probe into their mechanical properties. The tests used were: layer distance of PCN, tensile, impact, shore‐hardness, wearing tests, and so on. In addition, we used XRD to make the characterization analysis, and compare it to scatter and layer‐distance. It was found that when the MA is increased into the MMT, the layer‐distance at 3 wt% increased from 2.11 nm to 3.54 nm; when increasing the TPO into the MMT, layer‐distance at 3 wt% increased to the 3.28 nm. For the mechanical property, it was found that these specimens grafted with the MA have the following results: in the tensile test, the MMT weight percentage of 1 wt% had the best result, increasing by 3.2%. In the shore hardness test, the MMT of 3 wt% strengthens by 5.41%. In addition, the mechanical property of the specimens that grafted to the TPO decreased almost immediately at 1 wt%, but increased at 3–5 wt% trends. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers

Characterization and mechanical properties of high density polyethylene/silane montmorillonite nanocomposites

In order to understand and improve these soft and weak mechanical properties of High Density Polyethylene (HDPE), we add a silane modifier (Nanocor I.31PS) Montmorillonite (MMT) as reinforcement material, then use two kinds of different surfactant: thermoplastic polyolefin elastomers (TPO) or Maleic Anhydride (MA), to join the pieces of HDPE together, making it possess polarization. After that, use a Plastograph-Mixer by the twin-screw mixed method to obtain standard shaped specimens of Polymer-Clay Nanocomposites (PCN) to prepare HDPE/MMT nanocomposites pellets. By adding the different weight percentages (1, 3, 5 wt.%) of MMT, and 2:1 ratio of MA and MMT, the layer distance of MMT and mechanical property of nanocomposites was investigated. The chemical structure and polymer morphology of these as-synthesized PCN specimens were characterized by wide-angle powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). In addition, we prepare these experimental specimens in order to probe into its mechanical properties. These tests used are: layer distance of PCN, tensile, impact, shore-hardness, wearing tests, and so on. In addition, use XRD to accomplish the characterization analysis — comparing it to scatter and layer-distance. It is found that adding the MA into the MMT, layer-distance at 5 wt.% MMT increase from 2.11 nm to 3.55 nm; and add the TPO into the MMT, layer-distance at 5 wt.% MMT increase to the 2.66 nm. In the mechanical property, it is found that these specimens grafting with the MA have the following results: In the tensile test, the MMT weight percentage 3 wt.% has the best result, increased by 0.26%. In the shore hardness test, the MMT 3 wt.%, strengthened by 0.62%. In the wearing test, the MMT 3 wt.%, strengthened by 2.6%. Moreover, these specimens graft the TPO have the following results: In the impact test, the MMT 5 wt.% has the best result, increased by 16.96%. In the shore hardness test, the MMT 5 wt.% strengthens by 11.11%.

The Effect of Acrylic Bone Cement Solidification Conditions on the Compressive Property

A few experiments are conducted to investigate the effects of different solidification process on the physical hardness and compressive strength of the home-made bone cement. 24 bone cement samples under different mixing conditions are prepared. The compressive strength, hardness and phase composition of bone cement samples are measured with electronic universal machine, Shore hardness tester and X-ray diffraction(XRD) respectively. The results show that the maximum compressive strength of 24 samples is 96.27MPa, and obviously superior to that of the clinical application of bone cement. The hardness of bone cement of group C( powder 20g and fluid 10ml, 80.43HD) and group D(powder 20g and fluid 12ml, 86.60HD) is higher than 80HD which is the clinical requirement.It is found by X-ray diffraction that the higher crystallinity could produce finer grain, which results in higher compressive strength and hardness with better ductility and toughness. Giving consideration to compressive strength and physical hardness and crystallinity of D3(20g:12ml, with stirring speed as 30 times/min and stirring time as 90 seconds), the solidification condition is best.

Study on the Relationship between the Restitution Coefficient and the Adhesion Strength of the Coating

By using shore hardness test method, the effects of adhesion strength, coating thickness, basic material, and hammer on the restitution coefficient are studied experimentally and theoretically. The results show that the restitution coefficient increases with the curvature radius of the hammer indenter. In the same condition, the larger the restitution coefficient, the stronger the adhesion strength, while the smaller the restitution coefficient, and the weaker the adhesion strength.

Preparation and mechanical properties of polypropylene / montmorillonite nanocomposites - After grafted with hard/soft grafting agent

Using a plastograph-mixer by the twin-screw mixed method to obtain the standard shaped specimens of polymer-clay nanocomposites (PCN), to prepare polypropylene (PP) / montmorillonite (MMT) nanocomposites pellets, grafting with two kinds of different surfactant − maleic anhydride (MA) or thermoplastic polyolefin elastomers (TPO). The chemical structure and polymer morphology of these as-synthesized PCN specimens were characterized by wide-angle powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). In addition, we prepare these experimental specimens in order to probe into its mechanical properties. These tests used are: layer distance of PCN, tensile, impact, shore-hardness, wearing tests, and so on. In addition, use XRD to make the characterization analysis, compare it to scatter and layer-distance. It is found that increasing the MA into the MMT, layer-distance at 5 wt% increase from 2.09 nm to 3.94 nm; and increase the TPO into the MMT, layer-distance at 1 wt% increase to the 3.27 nm. For the mechanical property, it is found that these specimens graft the MA have the following results: in the shore hardness test, the MMT weight percentage 5 wt% has the best result, increased by 51.2%. In the wearing test, the MMT 3 wt% strengthens by 81.48%. In addition, the specimens that graft the TPO, in the tensile test, increased by 5.79% have the best result.

The effect of soft‐segment structure on the properties of novel thermoplastic polyurethane elastomers based on an unconventional chain extender

AbstractThermoplastic polyurethane elastomers (TPUs) are now widely used because of their excellent properties that include high tensile and tear strength, and good abrasion, impact and chemical resistance. TPUs are multiblock copolymers with alternating sequences of hard segments composed of diisocyanates and simple diols (chain extenders) and soft segments formed by polymer diols. Commonly used hard segments for TPUs are derived from 4,4′‐diphenylmethane diisocyanate (MDI) and aliphatic diols. The aim of our research was to examine the possibility of obtaining TPUs with good tensile properties and thermal stability by using an unconventional aliphatic‐aromatic chain extender, containing sulfide linkages. Three series of novel TPUs were synthesized by melt polymerization from poly(oxytetramethylene) diol, poly(ε‐caprolactone) diol or poly(hexane‐1,6‐diyl carbonate) diol of number‐average molecular weight of 2000 g mol−1 as soft segments, MDI and 3,3′‐[methylenebis(1,4‐phenylenemethylenethio)]dipropan‐1‐ol as a chain extender. The structure and basic properties of the polymers were examined using Fourier transfer infrared spectroscopy, X‐ray diffraction, atomic force microscopy, differential scanning calorimetry, thermogravimetric analysis, Shore hardness and tensile tests. It is possible to synthesize TPUs from the aliphatic‐aromatic chain extender with good tensile properties (strength up to 42.6 MPa and elongation at break up to 750%) and thermal stability. Because the structure of the newly obtained TPUs incorporates sulfur atoms, the TPUs can exhibit improved antibacterial activity and adhesive properties. Copyright © 2011 Society of Chemical Industry

New thermoplastic poly(carbonate-urethane) elastomers

New thermoplastic poly(carbonate-urethane) elastomers Two series of novel thermoplastic poly(carbonate-urethane) elastomers, with different hard-segment content (30 - 60 wt %), were synthesized by melt polymerization from poly(hexane-1,6-diyl carbonate) diol of Mn = 2000 as a soft segment, 4,4'-diphenylmethane diisocyanate (MDI) or hexane-1,6-diyl diisocyanate (HDI) and 6,6'-[methylenebis(1,4-phenylenemethylenethio)]dihexan-1-ol as a chain extender. The structure and basic properties of the polymers were examined by Fourier transform infrared spectroscopy, X-ray diffraction analysis, atomic force microscopy, differential scanning calorimetry, thermogravimetric analysis, Shore hardness and tensile tests. The resulting TPUs were colorless polymers, showing almost amorphous structures. The MDI-based TPUs showed higher tensile strengths (up to 21.3 MPa vs. 15.8 MPa) and elongations at break (up to 550% vs. 425%), but poorer low-temperature properties than the HDI-based analogs.

Preparation and Study Hardness and Thermal Conductivity (Tc) to Polyester Resin Composite with (Titanium Dioxide, Zinc Oxide, Acrylonitril, Wood Flour Coconut

This study is attempt to improve thermal isolation through measuring thermal conductivity composite of on polyester resin with fillers of (TiO2, ZnO, Acrylonitril, wood flour Coconut (Wf). The grain size of the fillers is 200 µm. The number of samples is (16) in addition to the virgin sample; these samples are prepared by cast molding method for polyester with filler volume fractions (5%, 10%, 15% and 20%). Shore hardness tests were used to measure the hardness and Lee disk method for thermal conductivity. The experimental results showed that the (20% ZnO) sample has the maximum value of thermal conductivity where (20% w.f) has minimum thermal conductivity .on the other hand (15% ZnO) sample give the maximum value of hardness where (20% w.f) sample gave the minimum value of hardness. From this study there is an important factor that should be observed that is the relationship between hardness and thermal conductivity. The study prove that the experimental results satisfy the theoretical assumptions in that the additive material (fillers) of metals base increase thermal conductivity where the material of cellulose base decrease the thermal conductivity and give good thermal isolation but with low hardness and all the result above the refry sample .

Preparation and Study Hardness and Thermal Conductivity (Tc) to Polyester Resin Composite with (Titanium Dioxide, Zinc Oxide, Acrylonitril, Wood Flour Coconut

This study is attempt to improve thermal isolation through measuring thermal conductivity composite of on polyester resin with fillers of (TiO2, ZnO, Acrylonitril, wood flour Coconut (Wf). The grain size of the fillers is 200 µm. The number of samples is (16) in addition to the virgin sample; these samples are prepared by cast molding method for polyester with filler volume fractions (5%, 10%, 15% and 20%). Shore hardness tests were used to measure the hardness and Lee disk method for thermal conductivity. The experimental results showed that the (20% ZnO) sample has the maximum value of thermal conductivity where (20% w.f) has minimum thermal conductivity .on the other hand (15% ZnO) sample give the maximum value of hardness where (20% w.f) sample gave the minimum value of hardness. From this study there is an important factor that should be observed that is the relationship between hardness and thermal conductivity. The study prove that the experimental results satisfy the theoretical assumptions in that the additive material (fillers) of metals base increase thermal conductivity where the material of cellulose base decrease the thermal conductivity and give good thermal isolation but with low hardness and all the result above the refry sample .

Predicting the relationships between brittleness and mechanical properties (UCS, TS and SH) of rocks

This paper presents the evaluation of uniaxial compressive strength (UCS) predicted from Shore hardness (SH) tests and to correlate brittleness concepts, which are derived from UCS, tensile strength (TS) and Shore hardness values of rock samples. Suggested empirical equations obtained from previous studies are summarised in order to predict UCS value of rocks from SH value. The data of UCS, TS and SH used in previous studies are limited and it was seen that the majority of correlation coefficients of the suggested empirical equations are low. However, the raw data used in this study showed a wide range of strength values of UCS (5.7 - 464 MPa), TS (0.5 - 30.5 MPa) and SH (9 - 100). A dataset containing 143 rock sample records from previous different studies, ranging from weak rock to very strong rocks, was used to investigate the relationships between SH and both UCS and three brittleness concepts. Regression analyses were performed and based on which empirical relationships between the physical-mechanical properties of rocks were developed. The relationships between SH and UCS, TS and Brittleness were investigated. The relationship between SH and the brittleness concept of B3 were found to be more significant than the other brittleness concepts. In this study, the physico-mechanical properties of the rocks investigated, present a wider range of data. Hence, the relationship established between UCS and SH is considered to be more reliable. Key words: Shore hardness, mechanical properties, brittleness.

An experimental and theoretical study of the effect of sample thickness on the Shore hardness of elastomers

Objective The Shore hardness test is a quick and convenient way to measure hardness of elastomers. The test specifies that the specimen should be at least 6 mm thick; however, published work in the literature indicates that workers often use much thinner samples. The aim of this study was to investigate the effect of thickness on the measured hardness of a range of dental elastomers and develop a theoretical relationship to predict the effect. Methods 7 dental silicone elastomers were selected to give a range of hardness values. Shore A scale hardness measurements were made on standard thickness samples, and those of lower thicknesses. A theoretical analysis was derived, whereby the effect of thickness of the sample on its measured hardness can be predicted and was tested using the results obtained. Results The results show reasonable agreement between theoretical and experimental values. The measured Shore hardness increased inversely with thickness, the effect being most pronounced with thin samples. Results ranged from 66.3 ± 1.6–80.9 ± 0.4 for 1 mm thick to 35.0 ± 1.7–69.1 ± 0.6 for the 6 mm thickness. Ratio of the measured hardness of 1 mm/6 mm ranged from 1.97 for the softest material to 1.17 for the hardest. Significance Measurements obtained with a Shore A hardness tester on samples of less than the specified 6 mm thickness will give erroneously high values, the error being greater as thickness decreases. The theoretical treatment proposed gives a basis on which data obtained from studies that used thinner specimens can be better analysed.