scholarly journals Synthesis and Characterization of Phosphorus- and Carborane-Containing Polyoxanorbornene Block Copolymers

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 613 ◽  
Author(s):  
Kahraman ◽  
Wang ◽  
von Irmer ◽  
Gallei ◽  
Hey-Hawkins ◽  
...  
Keyword(s):  
Block Copolymer ◽  
Block Copolymers ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Phosphonic Acid ◽  
Inductively Coupled Plasma ◽  
Gravimetric Analysis ◽  
Ceramic Yield ◽  
Block Polymer

Grubbs-catalyzed ring-opening metathesis polymerization (ROMP) of carborane- and phosphonate-containing monomers has been used for the generation of hybrid block copolymers. Molecular weights with Mn of 50,000 g/mol were readily obtained with polydispersity index values, Đ, between 1.03–1.08. Reaction of the phospha ester and carborane substituted oxanorbornene block copolymer with trimethylsilyl bromide led to a new polymer with phosphonic acid functionalities. In application studies, the phospha-carborane functionalized block polymer was tested as heat resistance material. Thermal stability was investigated by thermal gravimetric analysis (TGA) and microscale combustion calorimetry (MCC) analysis. Thermal treatment and ceramic yield under air were directly correlated to the carborane content of the block copolymer. However, phosphorus content in the polymer was more crucial for the char residues when heated under nitrogen atmosphere. The peak heat release rate (PHRR) increased as the number of phosphonate functionalities increased. However, corresponding phosphonic acid derivatives featured a lower heat release rate and total heat release. Moreover, the phosphonic acid functionalities of the block copolymer offer efficient chelating capabilities for iron nanoparticles, which is of interest for applications in biomedicine in the future. The complexation with iron oxide nanoparticles was studied by transmission electron microscopy (TEM) and inductively coupled plasma mass spectrometry (ICP–MS).

The influence of various/different ratios synthetic fiber mixture on the mechanical, thermal, morphological and flammability properties of poly (lactic acid)/polycarbonate blend

2020 ◽  
pp. 002199832096353
Author(s):  
Seda Hazer ◽  
Ayse Aytac
Keyword(s):  
Lactic Acid ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Control Sample ◽  
Synthetic Fiber ◽  
Poly Lactic Acid ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Limiting Oxygen Index

Poly (Lactic Acid) (PLA)/Polycarbonate (PC) blend has gained much attention as a bio-based polymeric material in various industrial fields. This study aims to improve the properties of PLA/PC blend reinforced with glass fiber (GF) and carbon fiber (CF) mixture to be produced for industrial use. For this purpose, 50PLA/50PC blend was prepared and used as a control sample. Then, 30% by weight CF and 30% GF were added to the matrix separately. To examine the effect of the use of CF and GF together, the composites were prepared as a mixture form of fibers by adding 5-10-15% CF and 5-10-15% GF, respectively, to the control blend in pairs. All composites compounded with the laboratory-scale twin-screw mini extruder and molded by injection molding. The effects of using synthetic fiber mixture were evaluated in terms of the mechanical, thermal and flammability properties. Differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), tensile test, scanning electron microscopy (SEM), limiting oxygen index (LOI), heat release rate (HRR) test were carried for the characterization of composites. The highest tensile strength values ​​and maximum % crystallinity values were obtained for the 15CF/15GF fiber mixture containing PLA/PC composite as 113.7 MPa and 21.4, respectively. CO yield (COY), HRR, and total heat release rate were reduced significantly by using synthetic fibers and fiber mixture.

scholarly journals A Study of the Thermal Degradation and Combustion Characteristics of Some Materials Commonly Used in the Construction Sector

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1833 ◽  
Author(s):  
Javier Arturo Piedrahita Solorzano ◽  
Khalid Abu Mohammad Moinuddin ◽  
Svetlana Tretsiakova-McNally ◽  
Paul Joseph
Keyword(s):  
Thermal Degradation ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Inner Core ◽  
Thermo Gravimetric Analysis ◽  
Gravimetric Analysis ◽  
Combustion Heat ◽  
Internal Core ◽  
Combustion Flow

In the present work, some materials that are commonly used in the construction industry were studied with regard to their thermal degradation characteristics and combustion attributes. These included façade materials for pre-fabricated houses, such as the layers of cross-laminated timber (CLT) and the inner core of aluminium composite panels (ACPs). The relevant investigations were carried out by employing thermo-gravimetric analysis (TGA) and pyrolysis combustion flow calorimetry (PCFC). The Arrhenius parameters and the associated calorimetric quantities, i.e., heat release rates, temperature to the peak heat release rate, heats of combustion, heat release capacities, and char yields, were also evaluated. These parameters showed that CLT is more fire retarded than the polymeric internal core of ACP façade materials. Furthermore, some valuable correlations among the various test quantities were found. For instance, a good correlation exists between the general profiles of the thermograms obtained through TGA runs and the heat release rate (HRR) traces from PCFC measurements. Depending on the nature of the materials, the char yields measured by PCFC can be 4–20 times higher than the ones obtained through TGA.

scholarly journals Effect of Magnesium Hydroxide and Aluminum Hydroxide on the Thermal Stability, Latent Heat and Flammability Properties of Paraffin/HDPE Phase Change Blends

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 180 ◽  
Author(s):  
Ru Zhou ◽  
Zhuang Ming ◽  
Jiapeng He ◽  
Yanming Ding ◽  
Juncheng Jiang
Keyword(s):  
Thermal Stability ◽  
Phase Change ◽  
Heat Release ◽  
Flame Retardant ◽  
Latent Heat ◽  
Aluminum Hydroxide ◽  
Heat Release Rate ◽  
Magnesium Hydroxide ◽  
Release Rate ◽  
Gravimetric Analysis

In this study, paraffin was selected as the phase change material (PCM) and high-density polyethylene (HDPE) as the supporting material to prepare a flame-retardant PCM system. The system consisted of paraffin, HDPE, expanded graphite (EG), magnesium hydroxide (MH) and aluminum hydroxide (ATH). The thermal stability and flame retardancy were studied by thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM) and cone calorimeter test (CONE). The SEM proved that the addition of MH and ATH can produce an oxide film on the surface of the composite material and form a “physical barrier” with the char layer, generated by the expansion of EG, preventing the transfer of heat and oxygen. The TGA test showed that, compared with other flame-retardant systems, the materials with added MH and ATH have a higher thermal stability and carbonization ability, and the amount of char residue has increased from 17.6% to 32.9%, which reduces the fire risk of the material. The flame retardant effect is obvious. In addition, the addition of MH and ATH has no significant effect on the phase transition temperature and latent heat value of PCMs. The CONE data further confirmed that MH and ATH can work with EG to prevent heat release, reduce the total heat release rate (THR) value and effectively suppress the generation of smoke, CO and CO2. The peak heat release rate (PHRR) value also decreased, from 1570.2 kW/m2 to 655.9 kW/m2.

Fire performance properties of commonly used South African hardwood

2020 ◽  
Vol 38 (5) ◽  
pp. 415-432
Author(s):  
Tebogo Maake ◽  
Joseph Asante ◽  
Bonex Mwakikunga
Keyword(s):  
Heat Release ◽  
South African ◽  
Thermal Performance ◽  
Heat Release Rate ◽  
Release Rate ◽  
Thermal Response ◽  
Growth Index ◽  
Gravimetric Analysis ◽  
Fire Hazards ◽  
Response Parameter

The effect of fire or heat and the associated fire hazards of South African hardwoods had been minimally researched. Quantitative investigations on fire performances of selected and common South African hardwood species that include Leadwood ( Combretum imberbe), Mopani ( Colophospermum mopane), Tamboti ( Spirostachys Africana), Stinkwood ( ocotea bullata), and Real Yellowwood ( Podocarpus latifolius) were undertaken using the cone calorimeter and the thermal gravimetric analysis instrument. The results indicated that Leadwood has the superior thermal performance. It has the lowest peak heat release rate (first peak at 156 kW/m2) at external heat irradiation flux of 75 kW/m2, highest thermal response parameter (376.2 kW s1/2/m2), highest thermal inertial (11.5 kW2 s/K2 m4), highest [Formula: see text], lowest fire growth index (derived from first heat release rate peak at 3120 W/s) and lowest smoke growth index (derived from first smoke production rate peaks at 0.760 m2/s2), and lowest smoke release (toxicity) 446.5 kg/kg. Bad thermal performance wood species are Mopani and Real Yellowwood. Stinkwood on the other hand has the best thermal stability from activation energy measurements.

Scale Modeling on the Effect of Air Velocity on Heat Release Rate in Tunnel Fire

2008 ◽  
Vol 18 (2) ◽  
pp. 111-124 ◽  
Author(s):  
C. Chen ◽  
L. Qu ◽  
Y. X. Yang ◽  
G. Q. Kang ◽  
W. K. Chow
Keyword(s):  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Air Velocity ◽  
Tunnel Fire ◽  
Scale Modeling

scholarly journals Effects of Discharge Area and Atomizing Gas Type in Full Cone Twin-Fluid Atomizer on Extinguishing Performance of Heptane Pool Fire under Two Heat Release Rate Conditions in an Enclosed Chamber

2021 ◽  
Vol 11 (7) ◽  
pp. 3247
Author(s):  
Dong Hwan Kim ◽  
Chi Young Lee ◽  
Chang Bo Oh
Keyword(s):  
Heat Release ◽  
Flow Rate ◽  
Heat Release Rate ◽  
Release Rate ◽  
Water Mist ◽  
Pool Fire ◽  
Sauter Mean Diameter ◽  
Discharge Area ◽  
Fire Extinguishing ◽  
Enclosed Chamber

In this study, the effects of discharge area and atomizing gas type in a twin-fluid atomizer on heptane pool fire-extinguishing performance were investigated under the heat release rate conditions of 1.17 and 5.23 kW in an enclosed chamber. Large and small full cone twin-fluid atomizers were prepared. Nitrogen and air were used as atomizing gases. With respect to the droplet size of water mist, as the water and air flow rates decreased and increased, respectively, the Sauter mean diameter (SMD) of the water mist decreased. The SMD of large and small atomizers were in the range of approximately 12–60 and 12–49 μm, respectively. With respect to the discharge area effect, the small atomizer exhibited a shorter extinguishing time, lower peak surface temperature, and higher minimum oxygen concentration than the large atomizer. Furthermore, it was observed that the effect of the discharge area on fire-extinguishing performance is dominant under certain flow rate conditions. With respect to the atomizing gas type effect, nitrogen and air appeared to exhibit nearly similar extinguishing times, peak surface temperatures, and minimum oxygen concentrations under most flow rate conditions. Based on the present and previous studies, it was revealed that the effect of atomizing gas type on fire-extinguishing performance is dependent on the relative positions of the discharged flow and fire source.

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