scholarly journals Studying the influence of the preparation of a new copolyamide as adhesive for wood-wood surfaces

2019 ◽  
Vol 17 (72) ◽  
pp. 109-116
Author(s):  
Mohammad N. AL-Baiati

In this research, a new copolyamid was prepared from reaction Aceglutamide with Formaldehyde by esterfication process, and used this copolymer as adhesive between wood – wood surface. Five different weight ( 0.2, 0.4 , 0.6, 0.8 & 1.0 gm ) from the prepared copolymer respectively, were used as adhesive to prepared the specimens of wood / adhesive . Four standard test methods were used to measured the adhesion properties which are; ASTM: D-790, ASTM: D- 695,  ISO – 179                   &   ASTM: D-638 . The results obtained from these tests indicated that, the specimens of               wood / adhesive containing 1.0 gm from the prepared copolymer have high values in all standard tests; Impact strength was 45 MPa, Compressive strength was 40 MPa, Flexural strength was 250 MPa and Tensile strength was 8150.41 MPa ; compared with the other specimens which contain on less weight from the prepared copolymer.

2015 ◽  
Vol 16 (1) ◽  
Author(s):  
Abul Hossain ◽  
Abu Syedwais Kurny

The effect of different scheduled artificial ageing hardness on the tensile and impact properties of Al-6Si-0.5Mg-2Ni alloy was studied. The solution treated Al-6Si-0.5Mg-2Ni alloy was aged isochronally for 1 hour at temperatures up to 300oC. The precipitation stages during ageing were monitored by hardness measurements. Tensile and impact properties were determined by standard tests. During artificial ageing, the yield and ultimate tensile strength were found to increase with ageing hardness; the maximum being attained at peak hardness. Ductility and impact toughness of the alloy, on the other hand decreased with ageing hardness, reaching the minimum at the highest hardness. The strength of Al- 6Si-0.5Mg-2Ni alloy was best at highest hardness but exhibits poor ductility and impact strength. KEYWORDS: Al-6Si-0.5Mg-2Ni alloy; ageing; hardness; tensile properties; impact strength;


TAPPI Journal ◽  
2011 ◽  
Vol 10 (7) ◽  
pp. 29-34
Author(s):  
TEEMU PUHAKKA ◽  
ISKO KAJANTO ◽  
NINA PYKÄLÄINEN

Cracking at the fold is a quality defect sometimes observed in coated paper and board. Although tensile and compressive stresses occur during folding, test methods to measure the compressive strength of a coating have not been available. Our objective was to develop a method to measure the compressive strength of a coating layer and to investigate how different mineral coatings behave under compression. We used the short-span compressive strength test (SCT) to measure the in-plane compressive strength of a free coating layer. Unsupported free coating films were prepared for the measurements. Results indicate that the SCT method was suitable for measuring the in-plane compressive strength of a coating layer. Coating color formulations containing different kaolin and calcium carbonate minerals were used to study the effect of pigment particles’ shape on the compressive and tensile strengths of coatings. Latices having two different glass transition temperatures were used. Results showed that pigment particle shape influenced the strength of a coating layer. Platy clay gave better strength than spherical or needle-shaped carbonate pigments. Compressive and tensile strength decreased as a function of the amount of calcium carbonate in the coating color, particularly with precipitated calcium carbonate. We also assessed the influence of styrene-butadiene binder on the compressive strength of the coating layer, which increased with the binder level. The compressive strength of the coating layer was about three times the tensile strength.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sekar Sanjeevi ◽  
Vigneshwaran Shanmugam ◽  
Suresh Kumar ◽  
Velmurugan Ganesan ◽  
Gabriel Sas ◽  
...  

AbstractThis investigation is carried out to understand the effects of water absorption on the mechanical properties of hybrid phenol formaldehyde (PF) composite fabricated with Areca Fine Fibres (AFFs) and Calotropis Gigantea Fibre (CGF). Hybrid CGF/AFF/PF composites were manufactured using the hand layup technique at varying weight percentages of fibre reinforcement (25, 35 and 45%). Hybrid composite having 35 wt.% showed better mechanical properties (tensile strength ca. 59 MPa, flexural strength ca. 73 MPa and impact strength 1.43 kJ/m2) under wet and dry conditions as compared to the other hybrid composites. In general, the inclusion of the fibres enhanced the mechanical properties of neat PF. Increase in the fibre content increased the water absorption, however, after 120 h of immersion, all the composites attained an equilibrium state.


Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2776 ◽  
Author(s):  
Wen-Cheng Liao ◽  
Po-Shao Chen ◽  
Chung-Wen Hung ◽  
Suyash Kishor Wagh

Tensile strength is one of the important mechanical properties of concrete, but it is difficult to measure accurately due to the brittle nature of concrete in tension. The three widely used test methods for measuring the tensile strength of concrete each have their shortcomings: the direct tension test equipment is not easy to set up, particularly for alignment, and there are no standard test specifications; the tensile strengths obtained from the test method of splitting tensile strength (American Society for Testing and Materials, ASTM C496) and that of flexural strength of concrete (ASTM C78) are significantly different from the actual tensile strength owing to mechanisms of methodologies and test setup. The objective of this research is to develop a new concrete tensile strength test method that is easy to conduct and the result is close to the direct tension strength. By applying the strut-and-tie concept and modifying the experimental design of the ASTM C78, a new concrete tensile strength test method is proposed. The test results show that the concrete tensile strength obtained by this proposed method is close to the value obtained from the direct tension test for concrete with compressive strengths from 25 to 55 MPa. It shows that this innovative test method, which is precise and easy to conduct, can be an effective alternative for tensile strength of concrete.


Author(s):  
Stephen Bond

While the oxidation of graphite in gaskets is a well known phenomenon it is often poorly quantified and the factors affecting it not always well known. There are some standard tests that can be used to determine graphite quality. While many of these material standards concentrate on the compositional impurities (sulfur, chlorides etc.) and the ash content; these are indicative of other properties and they are no real indication of oxidation performance. Recently, some test methods have been published that suggest a method for measuring oxidation performance; however, they have some shortcomings or constraints. Using modern, standard TGA (ThermoGravimetric Analysis), the work presented in this paper aims to provide a more detailed standard test that can be used to measure the oxidation rate of graphite in flowing air for a given set of time and temperature conditions. The paper will show what other conditions are critical and which are less significant in specifying a standard test. This will lead to the presentation of a suggestion for an improved standard test that builds on and further codifies the tests currently published. Finally, this paper will show the oxidation rates of a variety of different commercial graphite grades to illustrate the vast range of oxidation rates that are possible from the various grades of graphite.


Author(s):  
M. N. Meiirbekov ◽  
◽  
M. B. Ismailov ◽  

The paper presents published data on the effect of rubber elastomers on the strength properties of epoxy resin (ES) and carbon fiber. The introduction of 10% rubbers into ES ED-20 leads to an increase in compressive strength by 50%, tensile strength by 51%, impact strength by 133% and elongation by 128%. The optimal content of rubber with carboxyl groups for the OLDEN mixture was 10-12.5%, while the increase in compressive strength was 48%, impact strength - 73% and elongation - 187%. For DER 331 resin, the study was conducted with two hardeners Piperidine and DETA. The best results for Piperidine hardener were obtained on rubber with hydroxyl groups, with its optimal content of 2.5%, impact strength increased by 170%. For the hardener DETA, the best results were obtained on rubber with carboxyl groups at its optimal content of 10%, the increase in impact strength was 66%. When modifying carbon fiber with rubbers, it leads to a significant increase in the yield strength in tension by 42%, the modulus of elasticity in bending by 63%, and with a slight loss of impact strength.


Author(s):  
Mostafa Hassani Niaki ◽  
Morteza Ghorbanzadeh Ahangari ◽  
Abdolhossein Fereidoon

This paper studies the mechanical properties of polymer concrete (PC) with three types of resin systems. First, the effect of 0.5 wt% up to 3 wt% basalt fiber on the mechanical properties of a quaternary epoxy-based PC is investigated experimentally, and the best weight percentage of basalt fiber is obtained. The results show that adding basalt fiber to PC caused the greatest enhancement within 10% in compressive strength, 10% in flexural strength, 35% in the splitting tensile strength, and 315% in impact strength. In the next step, the effect of nanoclay particles on the mechanical properties of basalt fiber-reinforced PC (BFRPC) is analyzed experimentally. Nanoclays increase the compressive strength up to 7%, flexural strength up to 27%, and impact strength up to 260% but decrease the tensile strength of the PC. Field-emission scanning electron microscopy (FESEM) analysis is performed to study the fracture surface and morphology of various concrete specimens. In the last step, we consider the effect of two other different resin systems, rigid polyurethane and rigid polyurethane foam on the mechanical properties of reinforced polymer concrete. A comparison study presents that the epoxy PC has a higher specific strength than the polyurethane and ultra-lightweight polyurethane foam PC.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Navin Kumar ◽  
Ravinderjit Singh Walia ◽  
Surjit Angra

Purpose The purpose of this study is to develop jute-glass hybrid fibre reinforced polyester-based bio-composites using an indigenously developed pultrusion set-up and to present a detailed discussion on their mechanical characterization. Design/methodology/approach The work was carried out to observe the hybridization effect of natural and synthetic fibres in combination with hybrid fillers loading mainly on strength and other properties. The used hybrid fillers were a combination of 9 Wt.% of carbon black%, 6 Wt.% of eggshell ash powder and 6 Wt.% of coconut coir ash powder. A lab-based developed pultrusion set-up was used to develop these hybrid GJFRP composites of 1,500 mm length. The developed composites were tested for tensile strength, compressive strength and impact strength. Findings The maximum tensile, compressive and impact strength obtained are 88.37 MPa, 56.13 MPa and 731.91 J/m from 9 Wt.%, 9 Wt.% and 0 Wt.% of hybrid fillers loading, respectively. Breaking energy was found maximum as 7.31 J in hybrid glass-jute hybrid fibre reinforced plastic composites with no filler loading and it was observed that filler loading was decreasing the impact strength of developed hybrid composites. Shrinkage and its variations in the diameter of the finally developed cylindrical shape composites were observed after cooling and solidification. Scanning electron microscopy was used to observe the internal cracks, bonding of fibres and resin, voids, etc. Originality/value Development of hybrid filler based novel eco-friendly bio-composites and its experimental investigation on the impact strength, tensile strength and compressive strength has not been attempted yet.


2018 ◽  
Vol 162 ◽  
pp. 02012 ◽  
Author(s):  
Waleed Abbas ◽  
Eethar Dawood ◽  
Yahya Mohammad

The properties of foamed concrete reinforced with carbon fibres and hybrid fibres of carbon with polypropylene fibres has been studied. Various volumetric fractions of carbon fibres (0.5, 1 and 1.5%), hybrid fibres of carbon fibres (CF) with polypropylene fibres (PPF) as (1% CF + 0.5% PPF) & (0.5% CF + 1% PPF), also the mono polypropylene fibres as 1.5% PPF were used to reinforce foamed concrete mix. Fresh and hardened properties of all mixes included flowability, density, absorption, compressive strength, splitting tensile strength, and flexural strengths has been tested. Results showed that inclusion of carbon fibres up to 1% volumetric fraction may increase the compressive strength by about 36% higher than that of control mix. Whereas, the use of 1.5% carbon fibres exhibit significant increase in splitting and flexural tensile strengths by about 47 and 114%, respectively, compared to the reference mix. On the other hand, the hybridization of 1% CF + 0.5% PPF increased the splitting tensile strength and flexural strengths by 53% and 114%, respectively, compared with plain foamed concrete mix.


2020 ◽  
Vol 54 (30) ◽  
pp. 4853-4873 ◽  
Author(s):  
Lucas L Vignoli ◽  
Marcelo A Savi ◽  
Pedro MCL Pacheco ◽  
Alexander L Kalamkarov

The analysis of several micromechanical models for estimating strength of composite laminae is presented. Longitudinal tensile, compressive and in-plane onset shear strengths are analytically estimated and compared with experimental data available in the literature. The tensile longitudinal load predominantly induces rupture of fibers. On the other hand, the compressive strength is highly influenced by fiber misalignment, inducing a wide range of failure mechanisms. The material response to in-plane shear presents a strong nonlinear response. The estimation of longitudinal tensile strength based on the rule of mixture approaches is compared with 27 experimental data. A novel improvement is proposed assuming that in situ strength of fiber is smaller than fiber strength measured individually due to manufacturing induced damage. For the in-plane shear, 6 models are compared with 10 experimental stress-strain curves, including a novel closed-form expression based on the concentric cylinders model. Finally, for the longitudinal compressive strength, 8 micromechanical models, including a novel model to estimate misalignment effect in fiber crushing, are compared with 61 experimental data are analyzed. Results indicate that the minimal average error for the longitudinal tensile strength is 12.4% while for the compressive strength it is 15%. For the shear strength, the closest prediction depends on the strength definition and the proposed damage onset strength presents the best predictions. In general, the newly proposed models present the best estimations compared with the other models.


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