scholarly journals Effects of (complementary) Polyelectrolytes Characteristics on Composite Calcium Carbonate Microparticles Properties

2017 ◽  
Vol 54 (4) ◽  
pp. 708-714
Author(s):  
Cristian Barbu Mic ◽  
Marcela Mihai ◽  
Cristian Dragos Varganici ◽  
Simona Schwarz ◽  
Dan Scutaru ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Calcium Carbonate ◽  
Polymer Network ◽  
Weight Ratio ◽  
Crosslinking Density ◽  
Molar Ratio ◽  
Polyelectrolyte Complexes ◽  
Supersaturated Solutions ◽  
Thermal Stability Of ◽  
Flow Particle

This study follows the possibility to tune the thermal stability of some CaCO3/polymer composites by crystal growth from supersaturated solutions controlled by polymer structure or by using nonstoichiometric polyelectrolyte complexes (NPECs). As the ratio between the organic and inorganic parts in the composites controls the Ca2+/polymer network crosslinking density, the CaCO3/polymer weight ratio was kept constant at 50/1, varying the initial concentration of the polyanions solutions (0.05 or 0.06 wt.%), the NPECs molar ratio , n+/n- (0.2 or 0.4), or the inorganic precursors concentration (0.25 or 0.3 M). Poly(2-acrylamido-2-methylpropanesulfonic acid-co-acrylic acid) (PSA) and chondroitin-4-sulfate (CSA) were used as polyanions. Some NPEC dispersions, prepared with the same polyanions and poly(allylamine hydrochloride) (PAH), were also used for calcium carbonate crystallization. The characteristics of the prepared composites were investigated by scanning electron microscopy (SEM), flow particle image analysis (FPIA), particles charge density (CD), zeta-potential (ZP). The thermal stability of the composite particles was investigated as compared to bare CaCO3 microparticles prepared at the same initial inorganic concentrations.

scholarly journals Optimization of Polyamide Pulp-Reinforced Silica Aerogel Composites for Thermal Protection Systems

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1278
Author(s):  
Mariana E. Ghica ◽  
Cláudio M.R. Almeida ◽  
Mariana Fonseca ◽  
António Portugal ◽  
Luísa Durães
Keyword(s):  
Thermal Stability ◽  
Thermal Protection ◽  
Molar Ratio ◽  
Experimental Procedure ◽  
Thermal Protection Systems ◽  
Protection Systems ◽  
Density Values ◽  
Polyamide Fibers ◽  
First Time ◽  
Thermal Stability Of

The present work describes for the first time the preparation of silica-based aerogel composites containing tetraethoxysilane (TEOS) and vinyltrimethoxysilane (VTMS) reinforced with Kevlar® pulp. The developed system was extensively investigated, regarding its physical, morphological, thermal and mechanical features. The obtained bulk density values were satisfactory, down to 208 kg·m−3, and very good thermal properties were achieved—namely a thermal conductivity as low as 26 mW·m−1·K−1 (Hot Disk®) and thermal stability up to 550 °C. The introduction of VTMS offers a better dispersion of the polyamide fibers, as well as a higher hydrophobicity and thermal stability of the composites. The aerogels were also able to withstand five compression-decompression cycles without significant change of their size or microstructure. A design of experiment (DOE) was performed to assess the influence of different synthesis parameters, including silica co-precursors ratio, pulp amount and the solvent/Si molar ratio on the nanocomposite properties. The data obtained from the DOE allowed us to understand the significance of each parameter, offering reliable guidelines for the adjustment of the experimental procedure in order to achieve the optimum properties of the studied aerogel composites.

scholarly journals Synthesis of a Novel Phosphorous-Nitrogen Based Charring Agent and Its Application in Flame-retardant HDPE/IFR Composites

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1062 ◽  
Author(s):  
Junlei Chen ◽  
Jihui Wang ◽  
Aiqing Ni ◽  
Hongda Chen ◽  
Penglong Shen
Keyword(s):  
Thermal Stability ◽  
Heat Release ◽  
Flame Retardant ◽  
Flame Retardancy ◽  
Fire Hazard ◽  
Weight Ratio ◽  
Charring Agent ◽  
Migration Percentage ◽  
Ul 94 ◽  
Thermal Stability Of

In this work, a novel phosphorous–nitrogen based charring agent named poly(1,3-diaminopropane-1,3,5-triazine-o-bicyclic pentaerythritol phosphate) (PDTBP) was synthesized and used to improve the flame retardancy of high-density polyethylene (HDPE) together with ammonium polyphosphate (APP). The results of Fourier transform infrared spectroscopy (FTIR) and 13C solid-state nuclear magnetic resonance (NMR) showed that PDTBP was successfully synthesized. Compared with the traditional intumescent flame retardant (IFR) system contained APP and pentaerythritol (PER), the novel IFR system (APP/PDTBP, weight ratio of 2:1) could significantly promote the flame retardancy, water resistance, and thermal stability of HDPE. The HDPE/APP/PDTBP composites (PE3) could achieve a UL-94 V-0 rating with LOI value of 30.8%, and had a lower migration percentage (2.2%). However, the HDPE/APP/PER composites (PE5) had the highest migration percentage (4.7%), lower LOI value of 23.9%, and could only achieve a UL-94 V-1 rating. Besides, the peak of heat release rate (PHRR), total heat release (THR), and fire hazard value of PE3 were markedly decreased compared to PE5. PE3 had higher tensile strength and flexural strength of 16.27 ± 0.42 MPa and 32.03 ± 0.59 MPa, respectively. Furthermore, the possible flame-retardant mechanism of the APP/PDTBP IFR system indicated that compact and continuous intumescent char layer would be formed during burning, thus inhibiting the degradation of substrate material and improving the thermal stability of HDPE.

Effect of Anthracite on Preparation of Ceramsite Using Red Mud

2013 ◽  
Vol 467 ◽  
pp. 3-7
Author(s):  
Hui Fen Yang ◽  
Lin Fei Lu ◽  
Bei Ping Jiang ◽  
Jin Long Zhang
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Scanning Electron Microscopy ◽  
Bulk Density ◽  
Red Mud ◽  
Absorption Rate ◽  
Weight Ratio ◽  
Foaming Agent ◽  
Thermal Stability Of ◽  
Scanning Electron

Based on analyzing of chemical composition, mineral composition and thermal stability of red mud, preparation of ceramisite, using anthracite added as foaming agent, was investigated. Internal structure was observed by scanning electron microscopy (SEM). The results showed the bulk density of ceramisite was obviously reduced by anthracite added. The ceramisite with bulk density of 1.30g/cm3, water absorption rate£ ̈WAR£©of 2.98% and cylinder compressive strength £ ̈CCS£©of 9.48 MPa was obtained when weight ratio of red mud/waste glass/bentonites/anthracite was at 73:15:11:1. Majority of porosity in ceramisite was closed based on SEM. The porosity of ceramisite was much higher when anthracite was added as foaming agent than only calcite in red mud was used as foaming agent. The bulk density of the former was lower than that of the latter.

LiFePO4/Li Batteries with Mixtures of Carbonate and Ionic Liquid [EMIM]+[TFSI]- as High Properties and Safety Electrolyte

2013 ◽  
Vol 275-277 ◽  
pp. 2375-2380 ◽  
Author(s):  
Fei Li ◽  
Shao Jun Wang ◽  
Li Wei ◽  
Wei Na Tao ◽  
Xue Yang Dong ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Room Temperature ◽  
Weight Ratio ◽  
Transference Number ◽  
Organic Electrolyte ◽  
Mixed Electrolyte ◽  
Coulomb Efficiency ◽  
Li Batteries ◽  
Thermal Stability Of ◽  
First Discharge Capacity

The electrolyte optimum composition consists of 1mol/L LiTFSI in the [EMIM]+[TFSI]-mixed with EC and DMC in weight ratio of 60:20:20. The LiFePO4/Li cell using 1 mol/L LiTFSI/([EMIM]+[TFSI]-/EC/DMC) as electrolyte show that the first coulomb efficiency was 90% and the first discharge capacity was 168mAh g-1. The 15th reversible capacities were maintain 157mAh g-1at 0.2C. Compared with traditional organic electrolyte and pure IL electrolyte, IL-based mixed electrolyte have good coulomb efficiencies and higher charge and discharge performances. The lithium transference number of IL-based mixed electrolyte at room temperature are 0.59. Thermal stability of IL-based mixed electrolyte higher than traditional organic electrolyte, and show almost non-flammability by the burning tests.

Study on the Effect of Distillation Residue in Corn Polyols Industry on Thermoplastic Starch

2011 ◽  
Vol 391-392 ◽  
pp. 940-944
Author(s):  
Ni Na Bao ◽  
Hong Fa Wu ◽  
Dong Hua Xue
Keyword(s):  
Thermal Stability ◽  
Corn Starch ◽  
Weight Ratio ◽  
Thermoplastic Starch ◽  
Hplc Method ◽  
Distillation Residue ◽  
Crystal State ◽  
Composition And Structure ◽  
Refinery Process ◽  
Thermal Stability Of

This study used distillation residue obtained from bio-refinery process of corn starch and glycerol as a plasticizer to prepare thermoplastic starch (TPS). Various weight ratios of distillation residue and glycerol was investigated, HPLC method was used to analysis the components of the distillation residue. The composition and structure of TPS were evaluated by FTIR, XRD and TGA. The results indicated that with the addition of mixed plasticizers, the structure of TPS was changed obviously from a crystal state to an amorphous one with an increasing thermal stability of TPS. The better TPS structure can be obtained when the weight ratio of distillation and glycerol is 3:7.

scholarly journals Mechanical, thermal and surface properties of polyacrylamide/dextran semi-interpenetrating network hydrogels tuned by the synthesis temperature

2013 ◽  
Vol 11 (2) ◽  
pp. 248-258 ◽  
Author(s):  
Maria Dinu ◽  
Maria Cazacu ◽  
Ecaterina Drăgan
Keyword(s):  
Thermal Stability ◽  
Polymer Network ◽  
Synthesis Temperature ◽  
Water Vapor Sorption ◽  
Interpenetrating Polymer Network ◽  
Vapor Sorption ◽  
Interpenetrating Network ◽  
Preparation Temperature ◽  
Thermal Stability Of ◽  
Network Morphology

AbstractThe mechanical, rheological, thermal, and surface behaviors of three polyacrylamide/dextran (PAAm/Dx) semi-interpenetrating polymer network (semi-IPN) hydrogels, prepared at 22°C, 5°C and −18°C, were investigated. The results were compared with those obtained on cross-linked PAAm without Dx synthesized under the same conditions. Hydrogels prepared at the lowest temperature were the most mechanically stable. The thermal stability of the semi-IPN hydrogels is slightly lower than the corresponding PAAm gels, irrespective of preparation temperature. The water vapor sorption capacity depended on the presence of Dx as well as preparation temperature, which determines the network morphology.

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