Home  About us  Contact
 

Property Characterization (property + characterization)

Distribution by Scientific Domains
Polymers and Materials Science85%

Selected Abstracts

Structural and Preliminary Explosive Property Characterizations of New 3,4,5-Triamino-1,2,4-triazolium (Guanazinium) Salts

PROPELLANTS, EXPLOSIVES, PYROTECHNICS, Issue 5 2008
Chaza Darwich
Abstract Two new highly stable energetic salts were synthesized in reasonable yield by using the high nitrogen-content heterocycle 3,4,5-triamino-1,2,4-triazole and resulting in its picrate and azotetrazolate salts. 3,4,5-Triamino-1,2,4-triazolium picrate (1) and bis(3,4,5-triamino-1,2,4-triazolium) 5,5,-azotetrazolate (2) were characterized analytically and spectroscopically. X-ray diffraction studies revealed that protonation takes place on the nitrogen N1 (crystallographically labelled as N2). The sensitivity of the compounds to shock and friction was also determined by standard BAM tests revealing a low sensitivity for both. B3LYP/6,31G(d,,p) density functional (DFT) calculations were carried out to determine the enthalpy of combustion (,cH(1)=,3737.8,kJ mol,1, ,cH(2)=,4577.8,kJ mol,1) and the standard enthalpy of formation (,fH°(1)=,498.3,kJ mol,1, (,fH°(2)=+524.2,kJ mol,1). The detonation pressures (P(1)=189×108,Pa, P(2)=199×108,Pa) and detonation velocities (D(1)=7015,m s,1, D(2)=7683,m s,1) were calculated using the program EXPLO5. [source]

Acrylic Bone Cements Modified With Bioactive Filler

MACROMOLECULAR SYMPOSIA, Issue 1 2009
Carlos Federico Jasso-Gastinel
Abstract Bioactive cuttlebone Sepia officinalis particles that contain collagen were used to fill poly (methyl methacrylate- co -styrene) bone cements, varying size and concentration of filler particles. Cuttlebone was characterized by X-ray diffraction and plasma atomic emission spectrophotometer. Maximum reaction temperature and cement setting time were determined for composites and reference (copolymer without filler), along with NMR determination of residual monomer concentration. Mechanical properties characterization included stress-strain, bending, compression, fracture toughness and storage modulus tests. Mechanical results for composites filled with 10 and 30% weight of cuttlebone, complied with norm requirements which opens the possibility for using cuttlebone particles as bioactive filler. [source]

Completely discontinuous organic/ inorganic hybrid nanocomposites by self-curing of nanobuilding blocks constructed from reactions of [HMe2SiOSiO1.5]8 with vinylcyclohexene

POLYMER INTERNATIONAL, Issue 11 2007
Norihiro Takamura
Abstract The reaction of 4-vinyl-1-cylcohexene with [HMe2SiOSiO1.5]8 provides tetra- and octa-2-cyclohexenylethyloctasilsesquioxanes. The tetrabifunctional [cyclohexenylethylMe2SiOSiO1.5]4 -[HMe2SiOSiO1.5]4 (average degree of functionalization) melts near 80 °C and can be cast and then cured (by thermal hydrosilylation) into transparent nanocomposite shapes. These materials, while not nanoporous, offer dielectric constants of 2.8,2.9 at 100 kHz to 3 MHz, and are air stable to temperatures , 400 °C. The resulting materials appear (by X-ray diffraction) to be partially ordered after curing. The octafunctional material also melts at low temperatures (ca 120 °C) and can be copolymerized with hydridosiloxanes to give similar materials with lower thermal stability. The synthesis and characterization of the starting materials is described, as well as thermal curing studies and properties characterization of the resultant nanocomposites. Copyright © 2007 Society of Chemical Industry [source]

Mechanical, flow, and morphological properties of talc- and kaolin-filled polypropylene hybrid composites

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2007
M. B. Abu Bakar
Abstract Polypropylene (PP) hybrid composites have been produced by compounding two types of mineral fillers, viz., talc and kaolin with PP copolymer using a twin screw extruder. The PP hybrid composite was injection-molded into dumbbell specimen for tensile, flexural, and impact properties characterizations. MFI and SEM studies were used to characterize the flow and morphological properties of the PP hybrid composites. The result shows that most of the hybrid composites showed a significant decrease in flow, tensile, flexural, and impact properties compared with the single filler-filled PP composites. However, a hybridization effect was seen for the PPT20K10 hybrid composites, through the synergistic coalescence of positive characteristics from 20 wt % of talc and 10 wt % of kaolin. This hybrid formulation have given an economically advantageous material with the mechanical properties (tensile, flexural, and impact) comparable to those of the talc-filled PP composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 434,441, 2007 [source]

PEI,PEG,Chitosan-Copolymer-Coated Iron Oxide Nanoparticles for Safe Gene Delivery: Synthesis, Complexation, and Transfection

ADVANCED FUNCTIONAL MATERIALS, Issue 14 2009
Forrest M. Kievit
Abstract Gene therapy offers the potential of mediating disease through modification of specific cellular functions of target cells. However, effective transport of nucleic acids to target cells with minimal side effects remains a challenge despite the use of unique viral and non-viral delivery approaches. Here, a non-viral nanoparticle gene carrier that demonstrates effective gene delivery and transfection both in vitro and in vivo is presented. The nanoparticle system (NP,CP,PEI) is made of a superparamagnetic iron oxide nanoparticle (NP), which enables magnetic resonance imaging, coated with a novel copolymer (CP,PEI) comprised of short chain polyethylenimine (PEI) and poly(ethylene glycol) (PEG) grafted to the natural polysaccharide, chitosan (CP), which allows efficient loading and protection of the nucleic acids. The function of each component material in this nanoparticle system is illustrated by comparative studies of three nanoparticle systems of different surface chemistries, through material property characterization, DNA loading and transfection analyses, and toxicity assessment. Significantly, NP,CP,PEI demonstrates an innocuous toxic profile and a high level of expression of the delivered plasmid DNA in a C6 xenograft mouse model, making it a potential candidate for safe in vivo delivery of DNA for gene therapy. [source]

Nanoclay-reinforced syntactic foams: Flexure and thermal behavior

POLYMER COMPOSITES, Issue 8 2010
Mrinal C. Saha
Syntactic foams containing 60 vol% of hollow glass microballoons in epoxy matrix are modified with untreated nanoclays using combined mechanical and ultrasonication methods. Effects of nanoclays on flexure and thermal behavior of syntactic foams are investigated by adding different amount of nanoclays in the range of 1,3% by weight. Microscopic examinations and physical property characterization are performed to determine the interactions among constituent materials and the void formation during fabrication. It is found that the syntactic foams with 2 wt% nanoclays show the highest improvement in flexural properties (,42% strength and ,18% modulus) and dynamic mechanical properties (,30% storage modulus and ,28% loss modulus) properties. Thermal decomposition temperature is found to be unaffected by the addition of nanoclays, whereas a continuous reduction in the coefficient of thermal expansion (CTE) is observed. An examination of failure surface indicates that the failure is initiated on the tension side of the flexure sample due to fracturing of microballoons. POLYM. COMPOS., 31:1332,1342, 2010. © 2009 Society of Plastics Engineers [source]

Comparative mechanical property characterization of three indirect composite resin materials compared with two direct composites

POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 6 2003
Dr. Figen Demirel
Abstract Various new indirect composite materials have been developed with required advantages. In this study three indirect composite material (Artglass, Belleglass HP, Targis) were tested for flexural strength, fracture toughness, wear resistance and hardness against Filtek P60 and Z-100. Five specimens of each material were fabricated according to the manufacturer's directions. The flexural strength and fracture toughness was measured using the bending test. The wear test was performed to accelerated wear in a toothbrushing apparatus. Vickers hardness was measured for each of the tested materials. The statistical tests used for flexural strength, fracture toughness, wear and hardness were One-way ANOVA and Kruskal,Wallis test. The level of statistical significance chosen was p,=,0.05. Results of the study showed that Filtek P60 was superior to the other composites in all tests. Significant differences were found among the materials. The differences in flexural strength, fracture toughnes, wear and hardness may have been due to differences in chemistry or method of polymerization of the composites. Copyright © 2003 John Wiley & Sons, Ltd. [source]