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981.
982.
983.
Flammability and thermal degradation of epoxy acrylate modified with phosphorus‐containing compounds
A series of UV‐curable flame retardant resins was obtained using epoxy acrylate (EA) modified with 1‐oxo‐4‐hydroxymethyl‐2,6,7‐trioxa‐1‐phosphabicyclo[2.2.2]octane (PEPA). The flammability was characterized by limiting the oxygen index (LOI), UL 94 and cone calorimeter, and the thermal degradation of the flame retardant resins was studied using thermogravimetric analysis (TGA) and real time Fourier transform infrared (RTFTIR). The results indicated that the flame retardant efficiency increases and the heat release rate (HRR) decreases greatly with the content of PEPA. The TG data showed that the modified epoxy acrylates (MEAs) have lower initial decomposition temperatures and higher char residues than pure EA. The RTFTIR study indicates that the MEAs have lower thermal oxidative stability than the pure EA. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
984.
Poly(ethylene‐b‐ε‐caprolactone) (PE‐b‐PCL) diblock copolymers were synthesized by ring‐opening polymerization (ROP) of ε‐caprolactone (CL) with α‐hydroxyl‐ω‐methyl polyethylene (PE‐OH) as a macroinitiator and ammonium decamolybdate (NH4)8[Mo10O34] as a catalyst. Polymerization was conducted in bulk (130–150°C) with high yield (87–97%). Block copolymers with different compositions were obtained and characterized by 1H and 13C NMR, MALDI‐TOF, SAXS, and DSC. End‐group analysis by NMR and MALDI‐TOF indicates the formation of α‐hydroxyl‐ω‐methyl PE‐b‐PCL. The PE‐b‐PCL degradation was studied using thermogravimetric analysis (TGA) and alkaline hydrolysis. The PCL block was hydrolyzed by NaOH (4M), without any effect on the PE segment. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
985.
986.
Qingsheng Wang William J. Rogers M. Sam Mannan 《Journal of Thermal Analysis and Calorimetry》2009,96(1):225-233
Thermal degradation of copolymers, prepared from glycidyl methacrylate and acrylonitrile in varying molar ratios using 2,2′-azobisisobutyronitrile
as an initiator, was studied by thermogravimetry, derivative thermogravimetry, differential thermal analysis and mass spectrometry.
The fragmentation patterns in the mass-spectra were interpretable by comparison with the known degradation patterns of the
related materials. Thermal kinetic parameters, including activation energies and order of reaction of the degradation of the
prepared copolymers, were calculated from their thermoanalytical data. These parameters suggest an overall increase in thermal
stability with increasing content of acrylonitrile in the copolymers. 相似文献
987.
The thermal degradation of copolymers based on butyl acrylate-methyl acrylate-acrylic acid used as acrylic pressure-sensitive
adhesives, especially for bonding of plasticizer containing materials, has been investigated using thermogravimetry and pyrolysis-gas
chromatography at 250°C. It was observed that during the pyrolysis of butyl acrylate-methyl acrylate-acrylic acid copolymers
unsaturated monomers as methyl acrylate, methyl methacrylate, butyl acrylate and butyl methacrylate were formed. During the
side-chain butyl acrylate-methyl-acrylate-acrylic acid-copolymer degradation the presence of methyl alcohol and butyl alcohol
was observed. 相似文献
988.
An amphiphilic diblock copolymer PG‐b‐PCL with well‐controlled structure and pendant hydroxyl groups along hydrophilic block was synthesized by sequential anionic ring‐opening polymerization. The micellization and drug release of PG‐b‐PCL copolymers using pyrene as a fluorescence probe were investigated for determining the influences of copolymer composition and lipase concentration on drug loading capacity and controlled release behavior. The biodegradation of PG‐b‐PCL copolymers was studied with microspheres as research samples. It has been concluded that the polar hydroxyl groups along each repeat unit of hydrophilic PG block in PG‐b‐PCL copolymer have great influences on drug encapsulation, drug release, and enzymatic degradation of micelles and microspheres.
989.
The identification of ignitable liquid residues in fire debris is a key finding for determining the cause and origin of a
suspicious fire. However, the complex mixtures of organic compounds that comprise ignitable liquids are susceptible to microbiological
attack following collection of the sample. Biodegradation can result in selective removal of many of the compounds required
for identification of an ignitable liquid. Such degradation has been found to occur rapidly in substrates such as soil, rotting
wood, or other organic matter. Furthermore, fire debris evidence must often be stored for extended periods at room temperature
prior to analysis due to case backlogs and available evidence storage. Hence, extensive damage to ignitable liquid residues
by microbes poses a significant threat to subsequent laboratory work. In this work, the effects of microbial degradation of
ignitable liquids in soil have been evaluated as a function of time. Key findings include the loss of n-alkanes, particularly C9–C16, which showed the most dramatic decrease in gasoline as well as the petroleum distillates, while branched alkanes remained
unchanged. Monosubstituted benzenes also showed the most dramatic loss in gasoline. In the heavy petroleum distillates, n-alkanes with even carbon numbers were degraded more than n-alkanes with odd carbon numbers.
Figure A “fully involved” house fire in Indianapolis, IN
相似文献
John V. GoodpasterEmail: |
990.
Xiang-Hu Liu Jing Lin Hong-Wen Gao Ya-Lei Zhang 《Central European Journal of Chemistry》2009,7(3):454-460
The effects of Cu2+ on the catalytical degradation of acid chrome blue K (ACBK) in UV-TiO2 and H2O2 processes were studied. In these two processes, Cu2+ markedly depressed the catalytical degradation of ACBK by its interaction with ACBK. Through this interaction, the new complex
Cu(ACBK)2 formed. The formation of this new complex was favorable to protect some groups in ACBK from the oxidation of reactive oxygen
generated in UV-TiO2 and H2O2 processes, and consequently had suppressing effects on degradation of ACBK. In addition, Cu2+ also inhibited the degradation of ACBK in UV-TiO2 process by influencing the adsorption of ACBK on the surface of TiO2 particles.
相似文献