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Phase Content (phase + content)

Distribution by Scientific Domains

Polymers and Materials Science	100%

Distribution within Polymers and Materials Science

Polymer Science & Technology General	62%
Ceramics	25%

Selected Abstracts

Preparation of Machinable Fluoramphibole Glass,Ceramics from Soda-Lime Glass and Fluormica

INTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 4 2008
Weiyi Zhang
A novel route, directly mixing fluormica crystals with recycled soda-lime glass powder and then sintering, is proposed to fabricate machinable fluoramphibole glass,ceramics. The effect of fluormica addition on the sinterability, reactive crystallization behavior, strength, and machinability of the material was investigated. The relative densities of the glass,ceramics decreased with increasing fluormica content. An interaction between fluormica crystals and glass powder occurred during the sintering process. Diopside was formed in the glass,ceramics with 20 wt% fluormica, and fluorrichterite was formed in the glass,ceramics with more than 30 wt% fluormica. Machinability and strength of the glass,ceramics were improved with increasing crystalline phase content. [source]

Effect of flow history on poly(vinylidine fluoride) crystalline phase transformation

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2007
Hadi Sobhani
Abstract This study was devoted to the effect of extensional flow during film extrusion on the formation of the ,-crystalline phase and on the piezoelectric properties of the extruded poly(vinylidine fluoride) (PVDF) films after cold drawing. The PVDF films were extruded at different draw ratios with two different dies, a conventional slit die and a two-channel die, of which the latter was capable of applying high extensional flow to the PVDF melt. The PVDF films prepared with the two-channel die were drawn at different temperatures, strain rates, and strains. The optimum stretching conditions for the achievement of the maximum ,-phase content were determined as follows: temperature = 90°C, strain = 500%, and strain rate = 0.083 s,1. The samples prepared from the dies were then drawn under optimum stretching conditions, and their ,-phase content and piezoelectric strain coefficient (d33) values were compared at equal draw ratios. Measured by the Fourier transform infrared technique, a maximum of 82% ,-phase content was obtained for the samples prepared with the two-channel die, which was 7% higher than that of the samples prepared by the slit die. The d33 value of the two-channel die was 35 pC/N, which was also 5 pC/N higher than that of the samples prepared with the slit die. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 [source]

Catalytic Effects of Metals on Direct Nitridation of Silicon

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 8 2001
Varong Pavarajarn
Catalytic effects were investigated on the direct nitridation of silicon granules, impregnated with 0.125,2.0% by mass of calcium, yttrium, iron, copper, silver, chromium, or tungsten, in a stream of nitrogen with 10% hydrogen, using a tubular flow reactor operated at temperatures ranging from 1200° to 1390°C. Calcium and yttrium suppressed the formation of ,-silicon nitride while iron enhanced the formation of ,-silicon nitride over the temperature range investigated. An addition of 0.125% calcium resulted in about 99% overall conversion with 100%,-phase and a 2.0% yttrium addition yielded an overall conversion over 98% with an ,-phase content above 97%. Copper promoted not only the nitridation but the formation of ,-silicon nitride at 1200°C, but enhanced the ,-phase formation at higher temperatures. The role of liquid phases on the formation of ,-/,-silicon nitride was also discussed based on the nitridation of silicon impregnated with copper, calcium, silver, chromium, and tungsten. [source]

Organic,Inorganic Interactions in Poly(trimethylene carbonate),Titania Hybrids

MACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 21 2009
Elisa Cortecchia
Abstract Polycarbonate,titania hybrids have been synthesized by a sol,gel reaction, starting from poly(trimethylene carbonate) (PTMC) and titanium isoproproxide in different ratios. PTMC with a given chain length was obtained by ring opening polymerization. FT-IR spectra reveal the presence of TiOC covalent bonds between organic and inorganic phases, and their number increases with increasing inorganic phase content. Solvent extractions show that hybrid soluble fraction contains low PTMC chains with isopropoxide ends, which suggests that TiOC bond formation is mainly promoted by transesterification reactions of isopropyl alcohol onto the polymer chain, catalyzed by Ti compounds. Hybrid thermal properties reflect the combined effect of the decrease of PTMC molecular weight and of bond formation between PTMC and the inorganic network. The nanometric dimension of the TiO2 domains, confirmed by atomic force microscopy, provides optically transparent hybrids. [source]

Isotactic polypropylene solidification under pressure and high cooling rates.

POLYMER ENGINEERING & SCIENCE, Issue 11 2000
A master curve approach
Solidification in industrial processes very often involves flow fields, high thermal gradients and high pressures: the development of a model able to describe the polymer behavior becomes complex. Recently a new equipment has been developed and improved to study the crystallization of polymers when quenched under pressure. An experimental apparatus based on a modified, special injection moulding machine has been employed. Polymer samples can be cooled at a known cooling rate up to 100°C/s and under a constant pressure up to 40 MPa. Density, Micro Hardness (MH), Wide angle X-ray diffraction (WAXD), and annealing measurements were then used to characterize the obtained sample morphology. Results on one iPP sample display a lower density and a lower density dependence on cooling rate for increasing pressure. Micro hardness confirms the same trend. A deconvolution technique of WAXD patterns is used to evaluate the final phase content of samples and to assess a crystallization kinetics behavior. A master curve approach to explain iPP behavior under pressure and high cooling rates was successfully applied on density results. On the basis of this simple model it is possible to predict the final polymer density by superposition of the effect of cooling rate and the effect of pressure in a wide range of experimental conditions. [source]

Influence of the degree of grafting on the morphology and mechanical properties of blends of poly(butylene terephthalate) and glycidyl methacrylate grafted poly(ethylene- co -propylene) (EPR)

POLYMER INTERNATIONAL, Issue 8 2006
SL Sun
Abstract Poly(ethylene- co -propylene) (EPR) was functionalized to varying degrees with glycidyl methacrylate (GMA) by melt grafting processes. The EPR- graft -GMA elastomers were used to toughen poly(butylene terephthalate) (PBT). Results showed that the grafting degree strongly influenced the morphology and mechanical properties of PBT/EPR- graft -GMA blends. Compatibilization reactions between the carboxyl and/or hydroxyl of PBT and epoxy groups of EPR- graft -GMA induced smaller dispersed phase sizes and uniform dispersed phase distributions. However, higher degrees of grafting (>1.3) and dispersed phase contents (>10 wt%) led to higher viscosities and severe crosslinking reactions in PBT/EPR- graft -GMA blends, resulting in larger dispersed domains of PBT blends. Consistent with the change in morphology, the impact strength of the PBT blends increased with the increase in EPR- graft -GMA degrees of grafting for the same dispersion phase content when the degree of grafting was below 1.8. However, PBT/EPR- graft -GMA1.8 displayed much lower impact strength in the ductile region than a comparable PBT/EPR- graft -GMA1.3 blend (1.3 indicates degree of grafting). Morphology and mechanical results showed that EPR- graft -GMA 1.3 was more suitable in improving the toughness of PBT. SEM results showed that the shear yielding properties of the PBT matrix and cavitation of rubber particles were major toughening mechanisms. Copyright © 2006 Society of Chemical Industry [source]

Effects of malonic acid treatment on crystal structure, melting behavior, morphology, and mechanical properties of isotactic poly(propylene)/wollastonite composites

POLYMER COMPOSITES, Issue 6 2010
Lin Li
Wollastonite is treated with a new surface modifier (malonic acid). The influence of malonic acid treatment on the crystallization and mechanical properties of polypropylene (PP)/wollastonite composites has been studied. The results of differential scanning calorimetry, wide angle X-ray diffractometry, and polarized light microscopy prove that malonic acid-treated wollastonite increases the relative content of ,-crystal form of PP. The scanning electron microscopy shows that malonic acid-treated wollastonite has better compatibility with PP matrix than the untreated wollastonite. Higher ,-phase contents, smaller spherulite sizes, and better compatibility with PP matrix of the composites containing malonic acid-treated wollastonite result in improved impact strength and tensile strength, but lower flexural modulus. The results of Fourier transform infrared spectroscopy show that malonic acid reacts with the Ca2+ of wollastonite to form the calcium malonate, which acts as an effective ,-nucleating agent. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers [source]

Influence of the degree of grafting on the morphology and mechanical properties of blends of poly(butylene terephthalate) and glycidyl methacrylate grafted poly(ethylene- co -propylene) (EPR)