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Char Yield (char + yield)
Kinds of Char Yield Selected AbstractsDevelopment of fire-retarded materials,Interpretation of cone calorimeter dataFIRE AND MATERIALS, Issue 5 2007B. Schartel Abstract There is little consensus within the fire science community on interpretation of cone calorimeter data, but there is a significant need to screen new flammability modified materials using the cone calorimeter. This article is the result of several discussions aiming to provide guidance in the use and interpretation of cone calorimetry for those directly involved with such measurements. This guidance is essentially empirical, and is not intended to replace the comprehensive scientific studies that already exist. The guidance discusses the fire scenario with respect to applied heat flux, length scale, temperature, ventilation, anaerobic pyrolysis and set-up represented by the cone calorimeter. The fire properties measured in the cone calorimeter are discussed, including heat release rate and its peak, the mass loss and char yield, effective heat of combustion and combustion efficiency, time to ignition and CO and smoke production together with deduced quantities such as FIGRA and MARHE. Special comments are made on the use of the cone calorimeter relating to sample thickness, textiles, foams and intumescent materials, and the distance of the cone heater from the sample surface. Finally, the relationship between cone calorimetry data and other tests is discussed. Copyright © 2007 John Wiley & Sons, Ltd. [source] Energy production from the pyrolysis of waste biomassesINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 6 2009Selhan Karagöz Abstract Pyrolysis of waste biomasses was carried out at the temperatures of 450 and 500°C by heating at 5°C,min,1. Products were collected from emitted gases in a nitrogen purge stream; condensable liquids in the gases were collected by condensation. Gaseous, condensed liquid products and residual solids were collected and analyzed. Condensates were extracted with ether to recover the bio oils (BOs). The maximum liquid yield was obtained from the pyrolysis of soybean oil cake (SBOC) at 500°C with a yield of 60% ca. The BO was higher in the case of SBOC than that of sunflower oil cake (SFOC) at the temperatures of 450 and 500°C. With increasing temperature, bio char yield from the pyrolysis of SFOC decreased, while the liquid yield increased. The increase in temperature did not significantly affect the product distribution for the pyrolysis of SBOC. The compositions of BOs were similar for both SBOC and SFOC. Phenols, phenol derivatives including guaiacols and alkyl-benzenes were the most common and predominant in BOs from both the pyrolysis of SBOC and SFOC. Carbon dioxide was the major gas product for both SBOC and SFOC. Copyright © 2008 John Wiley & Sons, Ltd. [source] Preparation and properties of organic,inorganic hybrid composites based on polystyrene and an incompletely condensed polyvinylsilsesquioxane oligomerJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010Zhen Dai Abstract An incompletely condensed polyvinylsilsesquioxane (PVSQ) oligomer containing abundant silanol groups was synthesized and characterized by FTIR, 1H-NMR, 29Si-NMR, and MALDI-TOF-MS. Polystyrene/polyvinylsilsesquioxane (PS/PVSQ) hybrid composites were prepared by an in situ bulk polymerization. The hybrid composites showed higher Tg, Td, and char yield than PS homopolymer and without mechanical loss. The improvements in the properties of PS/PVSQ hybrid composites can be ascribed to the crosslinking function of PVSQ by silanol condensation in later processing. The hybrids showed different morphology from discrete microstructure to continuous network depending on the concentration of PVSQ. Because of the surface enrichment, a PVSQ protection layer was formed, which made the hybrid surface more hydrophobic. The structure and the reaction mechanism of PS/PVSQ hybrid composites were also investigated. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Synthesis and characterization of dicyanate monomers containing methylene spacersJOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2008G. Anuradha Abstract The bisphenols containing methylene spacer were prepared by treating eugenol/2-allyl phenol with 2,6-dimethyl phenol/guiacol/o -cresol in the presence of AlCl3. All the bisphenols were converted to their respective cyanate esters by treating with CNBr. The structural confirmation was done by FTIR, 1H NMR, 13C NMR spectral methods, and elemental analysis. Thermal characterization was done by DSC and TGA. DSC transition shows that the Tg is in the range of 208,239°C. The Tg is highest for the cyanate ester Cy(b) with symmetric structure. The Tg of the cured network depends on the length and symmetry of the monomer, Tg being higher for shorter and the para-substituted monomers. The T10 values are in the range of 364,381°C. The char yield is in the range of 47,53%. From the char yield, the limiting oxygen index (LOI) value was determined, which is used to confirm the flame retardancy of the cyanate ester resins. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Synthesis, cure kinetics, and thermal properties of the Bis(3-allyl-2-cyanatophenyl)sulphoxide/BMI blendsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008G. Anuradha Abstract A novel allyl functionalized dicyanate ester resin bearing sulfoxide linkage was synthesized. The monomer was characterized by Fourier Transform Infrared (FT-IR) Spectroscopy, 1H-, and 13C Nuclear Magnetic Resonance (NMR) spectroscopy and elemental analysis. The monomer was blended with bismaleimide (BMI) at various ratios in the absence of catalyst. The cure kinetics of one of the blends was studied using differential scanning calorimetry [nonisothermal] and the kinetic parameters like activation energy (E), pre-exponential factor (A), and the order of the reaction (n) were calculated by Coats-Redfern method and compared with those calculated using the experimental Borchardt-Daniels method. The thermal stability of the cured dicyanate, BMI, and the blends was studied using thermogravimetric analyzer. The initial weight loss temperature of dicyanate ester is above 380°C with char yield of about 54% at 800°C. Thermal degradation of BMI starts above 463°C with the char yield of about 68%. Inclusion of BMI in cyanate ester increases the thermal stability from 419 to 441°C. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Preparation, characterization, and properties of fluorene-containing benzoxazine and its corresponding cross-linked polymerJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 18 2010Ying-Ling Liu Abstract A benzoxazine compound (FDP-FBz), which possesses a fluorene group and two terminal furan groups, and its corresponding cross-linked polymer (CR-FDP-FBz) have been prepared using 4,4,-(9-fluorenylidene)diphenol (FDP), furfurylamine, and formaldehyde as precursors. The chemical structure of FDP-FBz has been characterized with Fourier-transform infrared and 1H nuclear magnetic resonance spectroscopies. FDP-FBz displays a melting point at about 173 °C and a processing window of 52 °C as well as good solubility in common organic solvents. As a result, FDP-FBz can be fabricated in both molten and solution processes. Under an excitation at 365 nm, FDP-FBz exhibits a photoluminescent (PL) emission at about 445 nm. The PL intensity of FDP-FBz is as high as sixfolds of the intensity recorded with FDP. CR-FDP-FBz displays a glass transition temperature of 215 °C, a high storage modulus of 3.1 GPa, a 10% weight loss at 384 °C, and a high char yield of 56 wt % (900 °C, in nitrogen). Moreover, CR-FDP-FBz has a high refractive index of about 1.65 as a result of incorporating fluorene groups to its structure. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 4020,4026, 2010 [source] Recent advancement on polybenzoxazine,A newly developed high performance thermosetJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 21 2009Yusuf Yagci Abstract Polybenzoxazine is a newly developed addition polymerized phenolic system, having a wide range of interesting features and the capability to overcome several shortcomings of conventional novolac and resole type phenolic resins. They exhibit (i) near zero volumetric change upon curing, (ii) low water absorption, (iii) for some polybenzoxazines Tg much higher than cure temperature, (iv) high char yield, (v) no strong acid catalysts required for curing, (vi) release of no byproduct during curing and also possess thermal and flame retarding properties of phenolics along with the mechanical performance. Though benzoxazine based materials possess several advantages, they have not yet became very attractive to the industries. To improve the mechanical properties and processibility several strategies have been reported including (i) synthesis of benzoxazine monomers with additional functionality, (ii) incorporation of benzoxazine in polymer chain, and (iii) benzoxazine based composites or alloys. In this article, we have discussed about the recent development of benzoxazine chemistry. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5565,5576, 2009 [source] Luminescent Monomer and Poly(methacrylate) Containing 1,3,4-Oxadiazole and Stilbene Units: Synthesis and Optical PropertiesMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 14 2004John A. Mikroyannidis Abstract Summary: A monomer M as well as a poly(methacrylate) P carrying the same chromophore, that consists of 1,3,4-oxadiazole and stilbene units, were efficiently synthesized. They dissolved in common organic solvents such as THF, chloroform, dichloromethane, 1,1,2,2-tetrachloroethane and chlorobenzene. P showed a Tg value of 145,°C. Both M and P were stable up to approximately 300,°C and afforded anaerobic char yield of about 40% at 800,°C. Their optical properties were comparable. They emitted intense violet-blue light in THF solution with a PL maximum at 413 nm and a PL quantum yield of 0.29 for M and 0.73 for P. Thin films of them displayed optical band gap of 3.03 eV and blue-light emission with a PL maximum around 440 nm. The PL curves of both samples were progressively red-shifted with increasing the solvent polarity. The influence of the annealing on the PL emission spectrum of M and P thin films was investigated. [source] Synthesis and characterization of Schiff-base-containing polyimidesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010Mousa Ghaemy Abstract Benzyl bisthiosemicarbazone and its complexes with nickel (NiLH4) and copper (CuLH4) were used as diamine monomers for the synthesis of new Schiff-base polyimides. The solution polycondensation of these monomers with the aromatic dianhydrides afforded metal-containing Schiff-base polyimides with inherent viscosities of 0.98,1.33 dL/g (measured in N -methyl-2-pyrrolidone at 25°C). The polyimides were generally soluble in a wide range of solvents such as N,N -dimethylformamide, N,N -dimethylacetamide, tetrahydrofuran, dimethyl sulfoxide, tetrachloroethane, hexamethylene phosphoramide, N -methyl-2-pyrrolidone, ethyl acetate, and pyridine at room temperature. The initial degradation temperatures of the resultant polyimides fell in the range of 220,350°C in nitrogen with char yields ranging from 36 to 64% at 700°C. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Preparation and properties of epoxy/phenol formaldehyde novolac/hexakis(methoxymethyl)melamine hybrid resins from in situ polymerizationJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2008Xinghong Zhang Abstract Based on the self-condensation of hexakis(methoxymethyl)melamine (HMMM), the condensation between HMMM and phenol formaldehyde novolac resin (n-PF), and the addition reaction of diglycidyl ether of biphenyl A (DGEBA) and n-PF, a homogeneous, transparent hybrid thermoset was prepared via in situ polymerization of DGEBA, n-PF, and HMMM. No phase separations were observed even for the DGEBA/n-PF/HMMM hybrid thermoset containing 40 wt % HMMM. These hybrid thermosets had high glass-transition temperatures (98,127°C from differential scanning calorimetry and 111,138°C from dynamic mechanical analysis), excellent thermal stability with high 5 wt % decomposition temperatures (>322°C), high char yields (>24 wt %), and improved flame retardancy with high limited oxygen indices (>28.5). The excellent overall properties of these hybrid resins may lead to their applications in high-performance "green" electronic products. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Synthesis and properties of novel organosoluble aromatic poly(ether ketone)s containing pendant methyl groups and sulfone linkagesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008Shou-Ri Sheng Abstract Several novel aromatic poly(ether ketone)s containing pendant methyl groups and sulfone linkages with inherent viscosities of 0.62,0.65 dL/g were prepared from 2-methyldiphenylether and 3-methyldiphenylether with 4,4,-bis(4-chloroformylphenoxy)diphenylsulfone and 4,4,-bis (3-chloroformylphenoxy)diphenylsulfone by electrophilic Friedel,Crafts acylation in the presence of N,N -dimethylformamide with anhydrous AlCl3 as a catalyst in 1,2-dichloroethane. These polymers, having weight-average molecular weights in the range of 57,000,71,000, were all amorphous and showed high glass-transition temperatures ranging from 160.5 to 167°C, excellent thermal stability at temperatures over 450°C in air or nitrogen, high char yields of 52,57% in nitrogen, and good solubility in CHCl3 and polar solvents such as N,N -dimethylformamide, dimethyl sulfoxide, and N -methyl-2-pyrrolidone at room temperature. All the polymers formed transparent, strong, and flexible films, with tensile strengths of 84.6,90.4 MPa, Young's moduli of 2.33,2.71 GPa, and elongations at break of 26.1,27.4%. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] A novel thermotropic liquid crystalline copolyester containing phosphorus and aromatic ether moity toward high flame retardancy and low mesophase temperatureJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 5 2010Xiang-Cheng Bian Abstract A series of thermotropic liquid crystalline polyesters containing phosphorus and aromatic ether groups (TLCP-AEs) were synthesized from p -acetoxybenzoic acid (p -ABA), terephthalic acid (TPA), 4,4,-oxybis(benzoic acid) (OBBA), and acetylated 2-(6-oxid-6H-dibenz(c,e) (1,2) oxaphosphorin 6-yl) 1,4-benzenediol (DOPO-AHQ). The chemical structure and the properties of TLCP-AEs were characterized by Fourier-transform spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (1H NMR), differential scanning calorimetry (DSC), X-ray diffraction (XRD), thermogravimetry analysis (TGA), scanning electronic microscopy (SEM), polarizing optical microscopy (POM), limiting oxygen index, and UL-94 tests, respectively. The results showed that TLCP-AEs had low and broad mesophase temperatures (230,400 °C). TLCP-AEs also showed excellent thermal stability; their 5%-weight-loss temperatures were above 440 °C and the char yields at 700 °C were higher than 45 wt %. All TLCP-AE polyesters exhibited high flame retardancy with a LOI value of higher than 70 and UL-94 V-0 rating. The SEM observation revealed that TLCP-AEs had good fibrillation ability. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1182,1189, 2010 [source] Highly stable electrochromic polyamides based on N,N -bis(4-aminophenyl)- N,,N,-bis(4- tert -butylphenyl)-1,4-phenylenediamineJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 9 2009Sheng-Huei Hsiao Abstract A new triphenylamine-containing aromatic diamine monomer, N,N -bis(4-aminophenyl)- N,,N,-bis(4- tert -butylphenyl)-1,4-phenylenediamine, was synthesized by an established synthetic procedure from readily available reagents. A novel family of electroactive polyamides with di- tert -butyl-substituted N,N,N,,N,-tetraphenyl-1,4-phenylenediamine units were prepared via the phosphorylation polyamidation reactions of the newly synthesized diamine monomer with various aromatic or aliphatic dicarboxylic acids. All the polymers were amorphous with good solubility in many organic solvents, such as N -methyl-2-pyrrolidinone (NMP) and N,N -dimethylacetamide, and could be solution-cast into tough and flexible polymer films. The polyamides derived from aromatic dicarboxylic acids had useful levels of thermal stability, with glass-transition temperatures of 269,296 °C, 10% weight-loss temperatures in excess of 544 °C, and char yields at 800 °C in nitrogen higher than 62%. The dilute solutions of these polyamides in NMP exhibited strong absorption bands centered at 316,342 nm and photoluminescence maxima around 362,465 nm in the violet-blue region. The polyamides derived from aliphatic dicarboxylic acids were optically transparent in the visible region and fluoresced with a higher quantum yield compared with those derived from aromatic dicarboxylic acids. The hole-transporting and electrochromic properties were examined by electrochemical and spectro-electrochemical methods. Cyclic voltammograms of the polyamide films cast onto an indium-tin oxide-coated glass substrate exhibited two reversible oxidation redox couples at 0.57,0.60 V and 0.95,0.98 V versus Ag/AgCl in acetonitrile solution. The polyamide films revealed excellent elcterochemical and electrochromic stability, with a color change from a colorless or pale yellowish neutral form to green and blue oxidized forms at applied potentials ranging from 0.0 to 1.2 V. These anodically coloring polymeric materials showed interesting electrochromic properties, such as high coloration efficiency (CE = 216 cm2/C for the green coloring) and high contrast ratio of optical transmittance change (,T%) up to 64% at 424 nm and 59% at 983 nm for the green coloration, and 90% at 778 nm for the blue coloration. The electroactivity of the polymer remains intact even after cycling 500 times between its neutral and fully oxidized states. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2330,2343, 2009 [source] Synthesis, photoluminescence, and electrochromic properties of wholly aromatic polyamides bearing naphthylamine chromophoresJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 20 2006Guey-Sheng Liou Abstract A series of novel polyamides with pendent naphthylamine units having inherent viscosities of 0.15,1.02 dL/g were prepared via direct phosphorylation polycondensation from various diamines and a naphthylamine-based aromatic dicarboxylic acid, 1-[N,N -di(4-carboxyphenyl)amino]naphthalene. These amorphous polyamides were readily soluble in various organic solvents and could be cast into transparent and tough films. The aromatic polyamides had useful levels of thermal stability associated with high glass-transition temperatures (268,355 °C), 10% weight loss temperatures in excess of 480 °C, and char yields at 800 °C in nitrogen higher than 60%. These polymers showed maximum ultraviolet,visible absorption at 350,358 nm and exhibited fluorescence emission maxima around 435,458 nm in N -methyl-2-pyrrolidinone solutions with fluorescence quantum yields ranging from 0.4 to 15.0%. The hole-transporting and electrochromic properties were examined with electrochemical and spectroelectrochemical methods. Cyclic voltammograms of the polyamide films cast onto an indium tin oxide coated glass substrate exhibited one oxidative redox couple around 1.08,1.16 V (oxidation onset potential) versus Ag/AgCl in an acetonitrile solution and revealed good stability of the electrochromic characteristics, with a color change from colorless to green at applied potentials ranging from 0 to 1.6 V. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6094,6102, 2006 [source] Synthesis and characterization of poly[phenyl(fluoroalkyloxaalkane)silanediyl]sJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 23 2003Vjacheslav V. Zuev Abstract Monomeric fluoroalkoxyalkyl(phenyl)dichlorosilanes were synthesized with quantitative yields by hydrosilylation of allyl ethers of fluoroalcohols with phenyldichlorosilane with Pt(Ph3Sb)2Cl2 complex as a catalyst. Starting from these monomers, corresponding polysilanes with weight-average molecular weights of 2,3 × 104 were obtained by the Wurtz reaction. Increasing the CF2 groups containing two to six monomer units caused the char yields to increase from 3 to 48% at 800 °C in air. The emission characteristics of these polysilanes in a chloroform solution were examined. They had a narrow peak at 344 nm with a small Stokes shift (,20 nm). © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3761,3767, 2003 [source] Synthesis and characterization of novel soluble triphenylamine-containing aromatic polyamides based on N,N,-bis(4-aminophenyl)- N,N,-diphenyl-1,4-phenylenediamineJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 16 2002Guey-Sheng Liou Abstract A new triphenylamine-containing aromatic diamine, N, N,-bis(4-aminophenyl)- N, N,-diphenyl-1,4-phenylenediamine, was prepared by the condensation of N,N,-diphenyl-1,4-phenylenediamine with 4-fluoronitrobenzene, followed by catalytic reduction. A series of novel aromatic polyamides with triphenylamine units were prepared from the diamine and various aromatic dicarboxylic acids or their diacid chlorides via the direct phosphorylation polycondensation or low-temperature solution polycondensation. All the polyamides were amorphous and readily soluble in many organic solvents such as N, N -dimethylacetamide and N -methyl-2-pyrrolidone. These polymers could be solution cast into transparent, tough, and flexible films with good mechanical properties. They had useful levels of thermal stability associated with relatively high glass-transition temperatures (257,287 °C), 10% weight-loss temperatures in excess of 550 °C, and char yields at 800 °C in nitrogen higher than 72%. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2810,2818, 2002 [source] | |||||||||||||