Modified MDF Composites Intended for the Refractory Application

2014 ◽  
Vol 1000 ◽  
pp. 114-117
Author(s):  
Jiří Másilko ◽  
Eva Bartoníčková ◽  
Radoslav Novotný

Paper deals with the preparation and characterization of MDF composite based on the strontium-aluminate cement. MDF composites show enhanced mechanical properties, especially flexural strength. Strontium-aluminate cement has got good thermal stability and capabilities at very high temperatures. MDF composites based on strontium-aluminate cement in combination with polyvinylalcohol were prepared by "high shear mixing" method. The prepared samples were subjected to high temperature solid state reaction at various temperatures. Characterization of MDF samples was mainly based on the methods of testing the flexural strength, X-Ray diffraction and thermogravimetry coupled with differential thermal analysis.

2021 ◽  
Author(s):  
Joanna Hrabia-Wiśnios ◽  
Beata Leszczyńska-Madej ◽  
Marcin Madej ◽  
Aleksandra Węglowska

Abstract The paper presents the results of research on the microstructure and selected mechanical properties of the SnSbCu bearing alloy after friction stir processing (FSP). The Whorl tool was used for modification; the process was carried out using two rotational speeds of the tool: 280 and 450 RPM and a constant linear speed of 355 mm/min. Microstructure studies were performed employing the techniques of light microscopy and scanning electron microscopy along with analysis of the chemical composition of micro-areas. Additionally, the phase composition was investigated by means of the X-ray diffraction method and statistical analysis of the precipitates present in the investigated alloy. In addition, hardness, flexural strength and uniaxial compression tests were performed before and after FSP modification. It was proved that using FSP to modify the SnSbCu alloy promotes refinement and homogenization of the microstructure, as well as improvement of the flexural strength, whereas no changes in the hardness level were found.


2019 ◽  
Vol 31 (5) ◽  
pp. 580-589 ◽  
Author(s):  
Wei Wang ◽  
Guofei Chen ◽  
Xingzhong Fang

Most of the existing polyimide oligomers for resin transfer molding (RTM) processing exhibited high melt viscosity, which can only maintain below 1 Pa·s at 280°C for 2 h, leading to very high process temperatures. So novel RTM-type oligomers with lower and stable melt viscosities are more desirable. Three series of thermoset oligoimides derived from 1,4-bis(3,4-dicarboxy phenoxy)benzene dianhydride and three different aromatic diamines were prepared herein. The diamines included 4,4′-oxydianiline, 2,2′-bis(trifluoromethyl)benzidine (TFDB), and 2-phenyl-4,4′-diaminodiphenyl ether ( p-ODA). 4-Phenylethynylphthalic anhydride was used as an endcapping reagent. Effects of the chemical structures and molecular weights of the oligoimides on their aggregated structures, melt processability, and the thermal and mechanical properties of the cured films were then systematically investigated. X-Ray diffraction results indicated that ODA series oligoimides and TFDB series oligoimides showed crystallinity in various degrees. However, the asymmetric p-ODA enables the p-ODA series oligoimides to exhibit amorphous forms. It was found that the p-ODA-based oligoimide with a molecular weight of 750 g mol−1 showed very low melt viscosity of 1 Pa·s even at 210°C, and the melt viscosity could maintain below 1 Pa·s after isothermal aging for 2 h at any temperature in the range of 200–280°C by rheological measurements. The cured film also showed a high glass transition temperature of 355°C by dynamic mechanical analysis, very good thermal stability by thermogravimetric analysis, and good mechanical properties. It might be more suitable for RTM processes in the future.


2021 ◽  
Author(s):  
Balaji Ayyanar Chninnappan ◽  
K. Marimuthu ◽  
C. Bharathiraj ◽  
B. Gayathri ◽  
S. K. Pradep Mohan

Abstract Samanea saman (SS) flower particulates were filled in Polylactic acid (PLA) composites were fabricated with different 0, 10, and 20 wt. % through the injection molding process. The elemental composition and morphology of SS PLA composites were studied through FESEM and Energy Dispersive X-ray analysis. Thermal stability of the SS PLA composites specimens was carried out through Thermo Gravimetric Analysis (TGA) and Differential Scanning Calorimeter (DSC). Crystal orientations studied through X-Ray Diffraction (XRD) showed the presence of the orthorhombic SS particulates. The properties of the composites were investigated such as tensile strength, compressive strength, flexural strength, and Shore D Hardness. It was found that 20 wt. % of SS filled PLA composites has a superior tensile strength of 43.76 MPa, the compression strength of 37.94 MPa, the flexural strength of 72.47 MPa, and Shore D Hardness of 80.1 SHN than pure PLA. SS particulates-filled PLA composites would be used for low-strength applications.


2013 ◽  
Vol 28 (4) ◽  
pp. 262-268 ◽  
Author(s):  
Jia-Yong Si ◽  
Ge-Mei Cai

Polycrystalline Sr3Sm2(BO3)4 borate has been synthesized through a solid-state reaction, and the title compound is stable in air and water. Its crystal structure was investigated from powder X-ray diffraction data using the Rietveld method. The fundamental building units of the crystal Sr3Sm2(BO3)4 are isolated BO3 anionic groups, distorted Sm–O polyhedra, and irregular Sr–O polyhedra, with the crystal structure isostructural to Sr3Nd2(BO3)4. The infrared spectrum of Sr3Sm2(BO3)4 has been measured, which is consistent with the crystallographic study. According to diffuse reflection measurement of Sr3Sm2(BO3)4 powders, the absorption edge is in the deep UV range and UV-vis transmittance is very high. Phosphor Sr3Sm2(BO3)4 exhibits an orange-red emission.


1990 ◽  
Vol 201 ◽  
Author(s):  
Christopher Scarfone ◽  
M. Grant Norton ◽  
C. Barry Carter ◽  
Jian Li ◽  
James W. Mayer

AbstractThin films of barium titanate (BaTiOs) have been deposited by pulsed-laser ablation onto (001)-oriented MgO substrates. The films were epitactic as evidenced by both x-ray diffraction and ion-channeling techniques. The film surface appeared smooth and contained a low density of particulates. This latter feature is believed to be due to the formation of target pellets having a very high density.


2019 ◽  
Vol 20 (1) ◽  
pp. 11
Author(s):  
A.A. Made Wisnu Wijaya Putra ◽  
W. G. Suharta ◽  
P. Suardana

Superconductor Y-247 (Y2Ba4Cu7O15-?) with adding silver (Ag) by using the wet-mixing method has been done. The synthesis process was carried out by calcination at 600o C for 3 hours and sintered at 925o C for 10 hours. Variations in the increase in the addition of Ag used were Ag0.05, Ag0.1, Ag0.15 and Ag0.2. Characterization of X-Ray Diffraction (XRD), showed an increase in the addition of Ag resulting in a decrease in the volume fraction, where the volume fractions obtained consecutive were 55.0%, 51.3%, 50.9% and 46.3%. Increasing the addition of Ag results in an increase in the lattice parameter values in the direction of the a axis which is 3.8247 Å, 3.8291 Å, 3.8292 Å, 3.8293 Å, decreasing the lattice parameter values in the b axis direction which is 3.8426 Å, 3.8415 Å, 3.8409 Å, 3.8383 Å and decreasing the lattice parameter values in the direction of the c axis are 49.2174 Å, 49.2022 Å, 49.1881 Å, 49.1761 Å. Analysis of the results of the characterization of Scanning Electron Microscopy (SEM), the particle size obtained was 225.47 nm, 202.88 nm, 190.68 nm and 172.22 nm.


2012 ◽  
Vol 554-556 ◽  
pp. 227-230
Author(s):  
Li Ying Zhang ◽  
Xiao Jing Zhao ◽  
Ping Chen ◽  
Sheng Di Fan

Five different multifunctional nitro octaphenyl silsesquioxane (NPS) were Synthesised and reduction was carried out to obtain amino octaphenyl silsesquioxane(APS). These compounds were characterized with elementary analysis, fourier transform infrared(FTIR), nuclear magnetic resonance (NMR, 29Si), wide-angle X-ray diffraction(XRD) and thermogravimetry (TG). Experiental results showed that the longer the nitration time, the more nitro connected to the OPS, but not positively, nitro number remained unchanged after five hours. NPS has good thermal stability than corresponding APS under 450°C, and the thermal stability of APS are decrease with the increase of amino number.


Author(s):  
Joanna Hrabia-Wiśnios ◽  
Beata Leszczyńska-Madej ◽  
Marcin Madej ◽  
Aleksandra Węglowska

AbstractThe paper presents the results of research on the microstructure and selected mechanical properties of the SnSbCu-bearing alloy after friction stir processing (FSP). The Whorl tool was used for modification; the process was carried out using two rotational speeds of the tool: 280 and 450 RPM and a constant linear speed of 355 mm/min. Microstructure studies were performed employing the techniques of light microscopy and scanning electron microscopy along with analysis of the chemical composition of micro-areas. Additionally, the phase composition was investigated by means of the X-ray diffraction method and statistical analysis of the precipitates present in the investigated alloy. In addition, hardness, flexural strength, and uniaxial compression tests were performed before and after FSP modification. It was proved that using FSP to modify the SnSbCu alloy promotes refinement and homogenization of the microstructure, as well as improvement of the flexural strength, whereas no changes in the hardness level were found.


2016 ◽  
Vol 29 (7) ◽  
pp. 836-848 ◽  
Author(s):  
Bhausaheb V Tawade ◽  
Nitin G Valsange ◽  
Prakash P Wadgaonkar

A new diacylhydrazide monomer, namely, 4-(4-(4-(4-(hydrazinocarbonyl)phenoxy)-2-pentadecylphenoxy)phenoxy) benzohydrazide (HPPDPB), was synthesized starting from 4-(4-hydroxyphenoxy)-3-pentadecylphenol. HPPDPB was polycondensed with terephthalic acid chloride (TPC), isophthalic acid chloride (IPC) and a mixture of TPC and IPC (50:50 mol%) to obtain polyhydrazides containing multiple arylene ether linkages in the backbone and pendent pentadecyl chains. Polyhydrazides were subsequently cyclized in the presence of phosphorus oxychloride to obtain the corresponding poly(1,3,4-oxadiazole)s. Polyhydrazides and poly(1,3,4-oxadiazole)s exhibited inherent viscosities in the range 0.65–0.72 dL g−1 and 0.54–0.62 dL g−1, respectively, which indicated the formation of reasonably high-molecular weight polymers. Polyhydrazides were soluble in polar aprotic solvents such as N,N-dimethylformamide, N,N-dimethylacetamide (DMAc), 1-methyl-2-pyrrolidinone and pyridine whereas poly(1,3,4-oxadiazole)s exhibited excellent solubility even in common organic solvents such as chloroform, dichloromethane and tetrahydrofuran. Tough, transparent and flexible films of polyhydrazides and poly(1,3,4-oxadiazole)s could be cast from DMAc and chloroform solutions, respectively. X-Ray diffraction studies revealed amorphous nature of polyhydrazides and poly(1,3,4-oxadiazole)s and the formation of layered structure was observed due to ordered packing of pentadecyl chains. The 10% decomposition temperature ( T10) values for poly(1,3,4-oxadiazole)s were in the range 425–440°C indicating their good thermal stability. Glass transition temperature ( Tg) values of polyhydrazides and poly(1,3,4-oxadiazole)s were in the range 175–192°C and 92–103°C, respectively. The excellent solubility characteristics and the large gap between Tg (92–103°C) and T10 (425–440°C) values give poly(1,3,4-oxadiazole)-containing pendent pentadecyl chains better opportunities for processability.


Sign in / Sign up

Export Citation Format

Share Document