A New Flame-Retardant Epoxy Composites Based on Silica and Metal Salt of Phosphinate

2013 ◽  
Vol 357-360 ◽  
pp. 1461-1464 ◽  
Author(s):  
Xue Qing Liu ◽  
Heng Zhou ◽  
Ji Yan Liu ◽  
Hao Wang ◽  
Shao Jun Cai
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Rice Husk ◽  
Oxygen Index ◽  
Metal Salt ◽  
Synergistic Effects ◽  
Combustion Time ◽  
Limiting Oxygen Index ◽  
Rice Husk Silica ◽  
Thermal Stability Of

The influence of silica on the mechanical properties, thermal stability and the flammability of epoxy (EP) blended with aluminum methylethylphosphinate (Al (MEP) has been studied by the limiting oxygen index (LOI), UL-94 test, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). Results show that adding silica enhances the mechanical properties of EP/Al (MEP). Synergistic effects between Al (MEP) and silica are obtained leading to the increase of LOI and to the reduction of combustion time. The TGA data demonstrate that silica can enhance the thermal stability of the EP/Al (MEP) and increase the char residue formation at high temperature. When the rice husk silica is substituted for silica, the composite presents lower LOI, lower thermal stability and char formation as well as inferior mechanical strength. The SEM results indicate that rice husk silica based composite shows poorer fillermatrix adhesion, which will be responsible for its inferior mechanical properties, lower thermal stability and flammability.

The Influence of Alkaline Treatment on Mechanical Properties and Morphology of Rice Husk Fibre Reinforced Polylactic Acid

2014 ◽  
Vol 911 ◽  
pp. 13-17 ◽  
Author(s):  
Abdullah Farah Dina ◽  
Sa’ad Siti Zaleha ◽  
Bonnia Noor Najmi ◽  
Ibrahim Nor Azowa
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Brittle Fracture ◽  
Polylactic Acid ◽  
Rice Husk ◽  
Alkaline Treatment ◽  
Distilled Water ◽  
Internal Mixer ◽  
Fesem Micrographs ◽  
Thermal Stability Of

This study focuses on the influence of surface treatment and fibre sizes on mechanical behavior, physical properties and morphology of rice husk fibre (RHF) reinforced polylactic-acid (PLA). Modified RHF was prepared by using 6w.t.% sodium hydroxide (NaOH) and distilled water. PLA composite reinforced with 25w.t.% volume fractions of modified RHF was mixed using the internal mixer and fabricated by the mini injection moulding. Tensile and flexural strength results showed that the PLA composite with 100, 200 and 500μm particles sizes of water treated fibre are much higher than those of alkaline treated. DSC measurement was performed and indicated that the Tg,Tmand ΔHmof PLA reduced after reinforcement with water treated and alkaline treated fibres. TGA results showed that the treatment reduced the thermal stability of the PLA. FESEM micrographs for flexural fractured surfaces of composites showed micro crack and pores due to brittle fracture of the PLA matrix adjacent to the fibre as a result of the brittle nature of the PLA resin.

scholarly journals Rigid Polyurethane Foams Reinforced with POSS-Impregnated Sugar Beet Pulp Filler

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5493
Author(s):  
Anna Strąkowska ◽  
Sylwia Członka ◽  
Agnė Kairytė
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Sugar Beet ◽  
Sugar Beet Pulp ◽  
Polyhedral Oligomeric Silsesquioxanes ◽  
Limiting Oxygen Index ◽  
Composite Foams ◽  
Beet Pulp ◽  
The Impact ◽  
Thermal Stability Of

Rigid polyurethane (PUR) foams were reinforced with sugar beet pulp (BP) impregnated with Aminopropylisobutyl-polyhedral oligomeric silsesquioxanes (APIB-POSS). BP filler was incorporated into PUR at different percentages—1, 2, and 5 wt.%. The impact of BP filler on morphology features, mechanical performances, and thermal stability of PUR was examined. The results revealed that the greatest improvement in physico-mechanical properties was observed at lower concentrations (1 and 2 wt.%) of BP filler. For example, when compared with neat PUR foams, the addition of 2 wt.% of BP resulted in the formation of PUR composite foams with increased compressive strength (~12%), greater flexural strength (~12%), and better impact strength (~6%). The results of thermogravimetric analysis (TGA) revealed that, due to the good thermal stability of POSS-impregnated BP filler, the reinforced PUR composite foams were characterized by better thermal stability—for example, by increasing the content of BP filler up to 5 wt.%, the mass residue measured at 600 °C increased from 29.0 to 31.9%. Moreover, the addition of each amount of filler resulted in the improvement of fire resistance of PUR composite foams, which was determined by measuring the value of heat peak release (pHRR), total heat release (THR), total smoke release (TSR), limiting oxygen index (LOI), and the amount of carbon monoxide (CO) and carbon dioxide (CO2) released during the combustion. The greatest improvement was observed for PUR composite foams with 2 wt.% of BP filler. The results presented in the current study indicate that the addition of a proper amount of POSS-impregnated BP filler may be an effective approach to the synthesis of PUR composites with improved physico-mechanical properties. Due to the outstanding properties of PUR composite foams reinforced with POSS-impregnated BP, such developed materials may be successfully used as thermal insulation materials in the building and construction industry.

scholarly journals Mechanical and Thermal Properties of Montmorillonite-Reinforced Polypropylene/Rice Husk Hybrid Nanocomposites

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1557 ◽  
Author(s):  
Khaliq Majeed ◽  
Ashfaq Ahmed ◽  
Muhammad Saifullah Abu Bakar ◽  
Teuku Meurah Indra Mahlia ◽  
Naheed Saba ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Thermal Properties ◽  
Rice Husk ◽  
Hybrid Nanocomposites ◽  
Commercial Application ◽  
Mechanical And Thermal Properties ◽  
Melt Mixing ◽  
Compatibilizing Agent ◽  
Thermal Stability Of

In recent years, there has been considerable interest in the use of natural fibers as potential reinforcing fillers in polymer composites despite their hydrophilicity, which limits their widespread commercial application. The present study explored the fabrication of nanocomposites by melt mixing, using an internal mixer followed by a compression molding technique, and incorporating rice husk (RH) as a renewable natural filler, montmorillonite (MMT) nanoclay as water-resistant reinforcing nanoparticles, and polypropylene-grafted maleic anhydride (PP-g-MAH) as a compatibilizing agent. To correlate the effect of MMT delamination and MMT/RH dispersion in the composites, the mechanical and thermal properties of the composites were studied. XRD analysis revealed delamination of MMT platelets due to an increase in their interlayer spacing, and SEM micrographs indicated improved dispersion of the filler(s) from the use of compatibilizers. The mechanical properties were improved by the incorporation of MMT into the PP/RH system and the reinforcing effect was remarkable as a result of the use of compatibilizing agent. Prolonged water exposure of the prepared samples decreased their tensile and flexural properties. Interestingly, the maximum decrease was observed for PP/RH composites and the minimum was for MMT-reinforced and PP-g-MAH-compatibilized PP/RH composites. DSC results revealed an increase in crystallinity with the addition of filler(s), while the melting and crystallization temperatures remained unaltered. TGA revealed that MMT addition and its delamination in the composite systems improved the thermal stability of the developed nanocomposites. Overall, we conclude that MMT nanoclay is an effective water-resistant reinforcing nanoparticle that enhances the durability, mechanical properties, and thermal stability of composites.

scholarly journals Investigating the Effect of Aluminum Diethylphosphinate on Thermal Stability, Flame Retardancy, and Mechanical Properties of Poly(butylene succinate)

2021 ◽  
Vol 8 ◽  
Author(s):  
Yiming Wang ◽  
Dayong Jiang ◽  
Xin Wen ◽  
Tao Tang ◽  
Karolina Szymańska ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Flame Retardancy ◽  
Oxygen Index ◽  
Butylene Succinate ◽  
Air Atmosphere ◽  
Cone Calorimeter Test ◽  
Filler Dispersion ◽  
Thermal Stability Of ◽  
Limited Oxygen

Poly(butylene succinate) is one of the most promising biodegradable polymers, but its applications are limited by poor flame retardancy. In this work, poly(butylene succinate)/diethylphosphinate (PBS/AlPi) composites were fabricated to investigate the effect of AlPi on their thermal stability, flame retardancy, and mechanical properties. It was found that the high content of AlPi decreased the thermal stability of PBS, and the decrease became stronger under the air atmosphere. When the content of AlPi reached 25wt%, the flame retardancy was improved with limited oxygen index (LOI) of 29.5%, V0 rating in UL-94 vertical burning test, and 49.3% reduction on the peak of heat release rate (PHRR) in cone calorimeter test. Meanwhile, the addition of AlPi could improve the mechanical properties of PBS with high tensile strength and Young’s modulus, which was ascribed to the compatible effect of maleic anhydride-grafted poly(butylene succinate) (PBS-g-MA) with good filler dispersion and strong matrix-particles interaction. Thus, the AlPi was an effective flame retardant to PBS, so that PBS/AlPi composites displayed excellent flame retardancy without seriously sacrificing other comprehensive performances.

scholarly journals Effects of chemical pre-treatment on structure and property of polyacrylonitrile based pre-oxidized fibers

2020 ◽  
Vol 15 ◽  
pp. 155892501989894
Author(s):  
Xiaolu Sun ◽  
Jiayin Song ◽  
Jin Zhang ◽  
Jingyan Liu ◽  
Huizhen Ke ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Heat Release ◽  
Flame Retardant ◽  
Oxygen Index ◽  
Energy Dispersive Spectrometer ◽  
Chemical Compositions ◽  
Limiting Oxygen Index ◽  
X Ray ◽  
Pre Treatment

Polyacrylonitrile-based pre-oxidized fibers with improved thermal stability, flame retardant, and mechanical properties were made from the pristine polyacrylonitrile fibers through chemical pretreatment followed by pre-oxidation in air. The morphological structure of the polyacrylonitrile-based pre-oxidized fibers was investigated by Fourier transfer infrared spectra, X-ray diffraction, scanning electron microscopy, and X-ray energy dispersive spectrometer. The changes of characteristic functional groups and chemical compositions confirmed the successful modification of the polyacrylonitrile fibers during pre-treatment. The grooves and cracks on the surface of polyacrylonitrile-based pre-oxidized fibers were remarkably decreased in comparison with that of pristine polyacrylonitrile fibers. The evolution of crystalline structure of the polyacrylonitrile fibers proved the occurrence of cyclization reactions during pre-oxidation. Meanwhile, thermal stability, flame retardant, and mechanical properties of polyacrylonitrile-based pre-oxidized fibers were also investigated by thermogravimetric analyzer, oxygen index meter, micro combustion calorimeter, and single fiber tensile tester, respectively. The results demonstrated that the polyacrylonitrile-based pre-oxidized fibers initially pre-treated by hydroxylamine hydrochloride, followed by monoethanolamine, had a high limiting oxygen index of 40.1 and breaking strength of 2.03 cN/dtex. The peak of heat release rate and total heat release of polyacrylonitrile-based pre-oxidized fibers decreased significantly while its charred residues increased, contributing to the improved flame retardant property.

scholarly journals Immobilization of Soybean Lipoxygenase on Nanoporous Rice Husk Silica by Adsorption: Retention of Enzyme Function and Catalytic Potential

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 291
Author(s):  
Putheary Ngin ◽  
Kyoungwon Cho ◽  
Oksoo Han
Keyword(s):  
Thermal Stability ◽  
Rice Husk ◽  
Thermal Inactivation ◽  
Specific Activity ◽  
Silica Particles ◽  
Soybean Lipoxygenase ◽  
Desorption Kinetics ◽  
Rice Husk Silica ◽  
Kinetics Of ◽  
Thermal Stability Of

Soybean lipoxygenase was immobilized on nanoporous rice husk silica particles by adsorption, and enzymatic parameters of the immobilized protein, including the efficiency of substrate binding and catalysis, kinetic and operational stability, and the kinetics of thermal inactivation, were investigated. The maximal adsorption efficiency of soybean lipoxygenase to the silica particles was 50%. The desorption kinetics of soybean lipoxygenase from the silica particles indicate that the silica-immobilized enzyme is more stable in an anionic buffer (sodium phosphate, pH 7.2) than in a cationic buffer (Tris-HCl, pH 7.2). The specific activity of immobilized lipoxygenase was 73% of the specific activity of soluble soybean lipoxygenase at a high concentration of substrate. The catalytic efficiency (kcat/Km) and the Michaelis–Menten constant (Km) of immobilized lipoxygenase were 21% and 49% of kcat/Km and Km of soluble soybean lipoxygenase, respectively, at a low concentration of substrate. The immobilized soybean lipoxygenase was relatively stable, as the enzyme specific activity was >90% of the initial activity after four assay cycles. The thermal stability of the immobilized lipoxygenase was higher than the thermal stability of soluble lipoxygenase, demonstrating 70% and 45% of its optimal specific activity, respectively, after incubation for 30 min at 45 °C. These results demonstrate that adsorption on nanoporous rice husk silica is a simple and rapid method for protein immobilization, and that adsorption may be a useful and facile method for the immobilization of many biologically important proteins of interest.

Preparation and Characterization of Lignin-Phenolic Foam

2011 ◽  
Vol 236-238 ◽  
pp. 1014-1018 ◽  
Author(s):  
Xiao Wei Zhuang ◽  
Shou Hai Li ◽  
Yu Feng Ma ◽  
Wei Zhang ◽  
Yu Zhi Xu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Oxygen Index ◽  
Lignin Content ◽  
Fire Retardant ◽  
Micro Structure ◽  
Critical Oxygen ◽  
Hole Structure ◽  
Thermal Stability Of

In this paper, lignin could partly replaced phenol to prepare lignin-phenolic(LPF) foam.The effects of amount of lignin on mechanical properties, thermal stability, fire-retardant and micro-structure of LPF foam. The results indicated that the addition of lignin decreased the brittleness and flexibility of foam, and the foam hole became larger in diameter and distributed more unevenly. When the lignin replacement amount was lower, the foam had regular foam hole structure and even distribution of foam hole, the size of foam hole increased with an increase of lignin content, SEM observations were in accordance with the early research of the mechanical properties of foams. And the addition of lignin slightly affected the fire-retardant and thermal stability of foam. When lignin replacement amount was 30% and 40%, the critical oxygen index of foam was even slightly higher than the pure PF foam.

Thermal Stability of Poly (vinyl chloride) Formulations Containing Iron Additives as a Replacement for Antimony Oxide

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Howell BA ◽  
Daniel YG ◽  
Butwin FJ ◽  
Weil ED
Keyword(s):  
Thermal Stability ◽  
Vinyl Chloride ◽  
Oxygen Index ◽  
Antimony Oxide ◽  
Iron Compounds ◽  
Limiting Oxygen Index ◽  
Poly Vinyl Chloride ◽  
Roll Mill ◽  
The Impact ◽  
Thermal Stability Of

Poly (vinyl chloride) [PVC] is a widely used commodity polymer with particular application for wire and cable coating, and for pipe and profile extrusion. For processing, PVC must be heavily plasticized. In addition, a number of other additives are usually introduced to promote thermal stability, to enhance processability and to inhibit flammability. Antimony oxide is often used in PVC formulations. However, the growing concern about the negative health and environmental impacts of antimony oxide has stimulated efforts to find suitable replacements. Iron compounds have been examined as suitable replacements for antimony oxide. PVC formulations containing 45 phr of Pevalen plasticizer, 50 phr of magnesium hydroxide and 2 or 10 phr of an iron additive were processed using a two-roll mill at 180°C. The thermal degradation and flammability of these materials have been evaluated utilizing thermogravimetry (TGA) and limiting oxygen index (LOI) measurements. All of the iron additives are effective in increasing LOI for combustion of the blends and in promoting char formation. The impact of the presence of all the iron additives is comparable and independent of the oxidation level of iron. Based on considerations of cost and availability, simple iron oxide may be the additive of choice. Keywords: PVC additives; Antimony oxide replacements; Combustibility of formulated PVC; Impact of additives on the thermal stability of PVC;

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