The Impact of Radiant Heat on the Flexural Strength and Impact Strength in Spruce Wood Bending

2020 ◽  
pp. 72-79
Author(s):  
Anton Osvald ◽  
Jaroslava Štefková
Author(s):  
Zahid Iqbal Khan ◽  
Zurina Binti Mohamad ◽  
Abdul Razak Bin Rahmat ◽  
Unsia Habib ◽  
Nur Amira Sahirah Binti Abdullah

This work explores a novel blend of recycled polyethylene terephthalate/polyamide 11 (rPET/PA11). The blend of rPET/PA11 was introduced to enhance the mechanical properties of rPET at various ratios. The work’s main advantage was to utilize rPET in thermoplastic form for various applications. Three different ratios, i.e. 10, 20 and 30 wt.% of PA11 blend samples, were prepared using a twin-screw extruder and injection moulding machine. The mechanical properties were examined in terms of tensile, flexural and impact strength. The tensile strength of rPET was improved more than 50%, while the increase in tensile strain was observed 42.5% with the addition of 20 wt.% of PA11. The improved properties of the blend were also confirmed by the flexural strength of the blends. The flexural strength was increased from 27.9 MPa to 48 MPa with the addition of 30 wt.% PA11. The flexural strain of rPET was found to be 1.1%. However, with the addition of 10, 20 and 30 wt.% of PA11, the flexural strain was noticed as 1.7, 2.1, and 3.9% respectively. The impact strength of rPET/PA11 at 20 wt.% PA11 was upsurged from 110.53 to 147.12 J/m. Scanning electron microscopy analysis revealed a dispersed PA11 domain in a continuous rPET matrix morphology of the blends. This work practical implication would lead to utilization of rPET in automobile, packaging, and various industries.


2011 ◽  
Vol 55-57 ◽  
pp. 447-450 ◽  
Author(s):  
Jian Li ◽  
Zheng Qun Huang ◽  
Yan Qin

In this article, a kind of SMC artificial marble was prepared. In order to enhance the mechanical properties and prolong the using life of SMC artificial marble, some effects such as fiber content, filler content and molding temperature etc. on the mechanical properties were carefully studied, too. Results showed that the increase of fiber content could improve the impact strength of SMC artificial marble when the fiber length was 10mm and the increase of filler content would decrease the flexural strength of SMC artificial marble. And the molding temperature at the range of 130°C ~ 160°C had little influence on the mechanical properties of SMC artificial marble. Comparing with natural marble and casting marble, SMC artificial marble owed superior overall performance and it was much more suitable for industry production.


2011 ◽  
Vol 236-238 ◽  
pp. 1725-1730 ◽  
Author(s):  
Wei Jen Chen ◽  
Ming Yuan Shen ◽  
Yi Luen Li ◽  
Chin Lung Chiang ◽  
Ming Chuen Yip

This study used carbon aerogels (CA) and phenolic resin in fixed proportations to produce nano high polymer resin, and used poly ehtylene oxide (PEO) as the modifying agent for phenolic resin to improve the mechanical properties of phenolic resin and promote the surface conductivity. The prepared nano high polymer resin and carbon cloth were made into nano-prepreg by using ultrasonic impregnation method, and a nano-prepreg composite material was prepared by using hot compacting and cut to test pieces to measure its mechanical properties and surface conductivity as well as the influence of temperature-humidity environment (85°C/168hr and 85°C/85%RH/168hr) on mechanical properties. The result showed that the surface conductivity increased by 64.55%, the tensile strength at room temperature increased by 35.7%, the flexural strength increased by 18.4%, and the impact strength increased by 101%. In hot environment (85°C/168hr), the tensile strength decreased by 23.8%, the flexural strength increased by 3.1%, and the impact strength increased by 84.6%. In high temperature-high humidity environment (85°C/85% RH/168hr), the tensile strength decreased by 29.6%, the flexural strength decreased by 17%, and the impact strength increased by 95.7%.Introduction


2009 ◽  
Vol 20 (2) ◽  
pp. 132-137 ◽  
Author(s):  
Rafael Leonardo Xediek Consani ◽  
Douglas Duenhas de Azevedo ◽  
Marcelo Ferraz Mesquita ◽  
Wilson Batista Mendes ◽  
Paulo César Saquy

The present study evaluated the effect of repeated simulated microwave disinfection on physical and mechanical properties of Clássico, Onda-Cryl and QC-20 denture base acrylic resins. Aluminum patterns were included in metallic or plastic flasks with dental stone following the traditional packing method. The powder/liquid mixing ratio was established according to the manufacturer's instructions. After water-bath polymerization at 74ºC for 9 h, boiling water for 20 min or microwave energy at 900 W for 10 min, the specimens were deflasked after flask cooling and finished. Each specimen was immersed in 150 mL of distilled water and underwent 5 disinfection cycles in a microwave oven set at 650 W for 3 min. Non-disinfected and disinfected specimens were subjected to the following tets: Knoop hardness test was performed with 25 g load for 10 s, impact strength test was done using the Charpy system with 40 kpcm, and 3-point bending test (flexural strength) was performed at a crosshead speed of 0.5 mm/min until fracture. Data were analyzed statistically by ANOVA and Tukey's test (α= 0.05%). Repeated simulated microwave disinfections decreased the Knoop hardness of Clássico and Onda-Cryl resins and had no effect on the impact strength of QC-20. The flexural strength was similar for all tested resins.


2020 ◽  
Vol 38 (8A) ◽  
pp. 1117-1125
Author(s):  
Teeb A. Mohameed ◽  
Sihama I. Salih ◽  
Wafaa M. Salih

 Many of the polymeric materials used for structural purposes have weak mechanical properties, these characteristics can therefore be improved by preparing a hybrid laminar composite. In this work use melting mixing method using screw extruder to prepare sheets of polymer blends and nanocomposites based on polymer blends, and using a hot hydraulic press machine to prepared hybrid laminates composites. Two groups of hybrid laminar composites were prepared, the first group is consist of [((94%PP: 5%PMMA: 1 %( PP-g-MA)): 0.3% ZrO2): 6%KF and 8%KF] and the second group is [((94%PP: 5%UHMWPE: 1 %( PP-g-MA)): 0.3% ZrO2): 6%KF and 8%KF]. The results illustrated the impact strength and fracture toughness are increase with increased weight percentage of Kevlar fiber in for both groups of laminar composites and the highest values for two groups are (58.1, 54.95 KJ/M2) and (8.4, 9.16 MPa√m) respectively, any that, at the rate of increment reached to (120.4%, 107%) and (52.7%, 66.5%) respectively, compared with the neat PP. Moreover, the flexural strength values of the first group samples of hybrid laminar composite remained constant, when added kevlar fiber to nanocomposite. While, the flexural strength values of the second group samples of hybrid laminar composite increase with increase the ratio of kevlar fiber in composite to reach the maximum values (92 MPa) at 8% wt. of kevlar fiber, any, at the rate of increment reached to 39.4% compared with the neat PP. As well as, the results shown that the flexural properties and fracture toughness of the second group samples higher than they are for the first group samples.


2005 ◽  
Vol 13 (4) ◽  
pp. 403-413
Author(s):  
Shanhua Zhou ◽  
Zhiyu Xu ◽  
Xin Liu ◽  
Yan Gao ◽  
Qingzhi Dong

A new interfacial modifier made of tetradecyl methylacrylate-maleic anhydride copolymer (TMA- co-MAH) was prepared and characterized. The effect of reaction time and monomer ratio on the gross conversion and MAH content in the copolymer was studied. When the glass mat was treated with TMA- co-MAH solutions and compounded with PP, the MAH group of the interfacial modifier formed strong interactions with the glass mat and the long side chain of the interfacial modifier entangled firmly with the polypropylene matrix. In comparison with maleated polyolefins, the higher MAH content of the TMA- co-MAH resulted in better interfacial adhesion between the PP and the glass mat resulting in increased flexural strength and modulus, and the ductility of the TMA- co-MAH introduced a ductile interlayer into the interface of the glass mat reinforced polypropylene composites (GMT-PPs) to achieve higher impact strength. Therefore the mechanical properties of composites treated with TMA- co-MAH were all superior to those of GMT-PPs treated with maleic anhydride grafted polypropylene (PP- g-MAH) solutions when they were used at the same level. The effects of anhydride content, concentration of copolymer and compounding time on the mechanical property of GMT-PPs were investigated. With the optimal monomer ratio, MAH:TMA = 7:3, a 3% copolymer solution and a compounding time of 5 min, the impact strength, flexural strength and modulus of GMT-PPs treated with the new interfacial modifier were all improved significantly compared with composites treated with 0.3% PP- g-MAH solution.


2011 ◽  
Vol 250-253 ◽  
pp. 839-842
Author(s):  
Chun He Yu ◽  
Shao Rong Lu ◽  
Zhi You Yang ◽  
Kuo Liu ◽  
Xin Fan

In order to enhance the interfacial interactions between the sisal fiber (SF) and the polypropylene (PP) matrix, a water-solubility hyperdispersant which has amphipathic structure and flexible segment was used. Experimental results revealed that when the content of hyperdispersant is 5 percent, the impact strength of the composites was 27.4 kJ·m-2 and the flexural strength of SF/PP composites was 40.1 MPa, which was 64 and 34 wt% higher than that of unmodified systems, respectively. Meanwhile, the crystallinity of the composites also leads to an increase.


Renewable natural fibres like kenaf can be used to produce composites as replacement to plastic boards in household and industrial applications. The objective of this study is to optimise the process parameters for compression moulding of kenaf polypropylene composite to get maximum tensile, flexural and impact strength values for three different blend ratios. Three levels of temperature (160oC, 180oC and 200 oC), compression pressure (7, 9 and 11 Mpa) and time of application (10,20 and 30 min ) for producing kenaf/ polypropylene blend ratios of 50:50, 65:35 and 80:20 have been used. The samples were produced through carding for web formation, needle punching for non woven making and finally in compression moulding machine for boards making. All the composite boards were analysed for tensile, flexural and impact strength. The tensile and flexural strengths have positive correlations with time and temperature and contact pressure in all the blend ratios kenaf / polypropylene. The impact strength has positive correlation with time, temperature whereas it has negative correlation with contact pressure in all the blend ratios. The highest tensile strength and flexural strength is achieved with 65:35 kenaf / polypropylene blend at 200 o C temperature, 11Mpa pressure and 10 minutes duration in compression moulding machine. The highest Impact strength is achieved with 80:20 blends at 180 o C, 7 Mpa pressure and 30 minutes duration. The tensile and flexural strength is the highest at the blend ratio of 65:35 whereas the Impact strength increases with the increase kenaf content up to 80%


Author(s):  
Darshan G. Gaidhankar ◽  
Mohammad Omid Naqshbandi ◽  
M. S. Kulkarni

The capability to absorb energy, often called as toughness, is of importance in actual service conditions of mesh reinforced composites, when they may be subjected to static, dynamic and fatigue loads. Toughness evaluated under impact loads is the impact strength. The toughness of materials are determined by two methods, (i) by measuring deformation under impact load, (ii) by determining energy adsorption capacity of materials under impact load. Several methods were used to investigate to determining toughness of materials. In this research work, drop weight impact test were used. The present experimental work describes testing of flat ferrocement panels with different number of layer steel mesh as well as enhancement of panels with steel fiber. The main purpose of this study is to investigate the effect of using different number of wire mesh layer on the flexural strength and impact strength and also effect of varying thickness of panels on the energy absorption of ferrocement panels. The experimental work includes preparation of ferrocement panels reinforced with welded square mesh, woven square mesh with and without hooked steel fibers The ferrocement panels of different sizes were prepared and tested for flexural strength under the two point loading as well as drop weight for impact testing. It is expected that as the mesh layers will be increased the energy absorption capacity of the panel should be increased and the also its effect should be seen for addition of hooked steel fibers.


2020 ◽  
Vol 8 (5) ◽  
pp. 3186-3192 ◽  

The investigation is intended to evaluate the impact of substitution of demolished concrete debris as coarse aggregate (CA) in pavement quality concrete (PQC). The strength characteristics of PQC such as compressive strength, tensile strength, flexural strength and impact strength after adding recycled coarse aggregate (RCA) are experimentally determined in laboratory environment. Specimens of M30 grade concrete were prepared and tested. The RCA was substituted up to 50% by replacing CA content. Based on the investigation results, it was found that reduction of slump value due to the substitution of RCA in concrete. There is no remarkable reduction of compressive strength and flexural strength up to 30% and 40 % replacement of CA respectively in all the curing periods. The impact strength was reduced due to addition of RCA and observed 8% reduction after adding 20% RCA. It is suggested that RCA may be used up to 20% as CA in PQC.


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