Characterization of liquid crystalline polyester polycarbonate blends

Malik, Tariq M.; Carreau, Pierre J.; Chapleau, N.

doi:10.1002/pen.760290906

Cited by 117 publications

(39 citation statements)

References 19 publications

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“…However, the upper part of the curve becomes higher with the increase of LCP weight fraction. The variability of Tg for immiscible LCP/PC blends has been the subject of other studies [25][26][27][28]. So far, the reason for the increase of Tg is not fully understood.…”

Section: Determination Of Phase Transition Temperaturesmentioning

confidence: 99%

“…The variation of free volume behavior in the blends cou1d be exp1ained in terms of this phenomenon. The phenomenon has also been reported to be the reason for phase separation in b1end systems with simi1ar components [26][27][28]. Malik et al [26] also used DSC to study the miscibility behavior in the blends ofVectra and PC (Lexan 130-111).…”

Section: Thermodynamic Phase Diagram For Binary Polymer Blends Contaimentioning

confidence: 99%

“…The phenomenon has also been reported to be the reason for phase separation in b1end systems with simi1ar components [26][27][28]. Malik et al [26] also used DSC to study the miscibility behavior in the blends ofVectra and PC (Lexan 130-111). The blends processed at 280°C were found to have limited miscibility due to the slightly lowered Tg in PC-rich phase.…”

Section: Thermodynamic Phase Diagram For Binary Polymer Blends Contaimentioning

confidence: 99%

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Phase Diagram for Liquid Crystalline Polymer/ Polycarbonate Blends

2003

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A novel mechanism to form binary polymer blends is through phase separation by spinodal decomposition in the unstable region of the phase diagram. The present work investigates the effects of thermally‐induced phase separation by spinodal decomposition on the morphology development of liquid crystalline polymer/polycarbonate blends. Moreover, a thermodynamic binary phase diagram is obtained using a twin‐screw extruder at various processing melt temperatures. Differential scanning calorimetry and scanning electron microscopy were used to study the miscibility of the blends and the resulting morphology. A thermodynamic binary phase diagram exhibiting a lower critical solution temperature was obtained. The droplet size distribution of the blend was also obtained and discussed in light of the Cahn‐Hilliard theory.

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Section: Determination Of Phase Transition Temperaturesmentioning

confidence: 99%

Section: Thermodynamic Phase Diagram For Binary Polymer Blends Contaimentioning

confidence: 99%

Section: Thermodynamic Phase Diagram For Binary Polymer Blends Contaimentioning

confidence: 99%

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Phase Diagram for Liquid Crystalline Polymer/ Polycarbonate Blends

2003

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“…5 been attempted to investigate the shear stress relaxation behavior. 12 In the measurements of the stress relaxation modulus, G(t), the decay of stress with time makes it possible to assess the bulk characteristics of a polymeric material. Figure 8 shows relaxation process of various polysulfone/TLCP blends with time at 280°C.…”

Section: Thermal Properties Of Polysulfone/tlcp Blendsmentioning

confidence: 99%

Rheology and Physical Properties of Polysulfone in-situ Reinforced with a Thermotropic Liquid-Crystalline Polyester

Hong

Kim

et al. 1991

Polym J

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ABSTRACT:Blending Amoco polysulfone Ude! P-1700 and Hoechst Celanese thermotropic liquid-crystalline polymer (TLCP) Vectra A-950 in a twin-screw extruder produced in-situ composites. An inclusion of TLCP did not notably change the thermal properties of polysulfone but the rheological properties were notably changed depending on the measured temperature and blend composition. In the vicinity of crystal-nematic transition temperature, an incorporation of TLCP into polysulfone increased the melt viscosity and gave rise to a large yield stress. Above the crystal-nematic transition temperature, however, TLCP dramatically decreased the melt viscosity and the resultant yield stress was very small. The tensile strength and modulus of as-spun polysulfone/TLCP fibers were increased as the TLCP content and spin draw ratio were increased. The increase in tensile strength with spin draw ratio was more noticed with the polysulfone/TLCP fiber containing higher TLCP content. Wide angle X-ray diffraction patterns suggested that the increase in tensile strength is ascribable to the enhanced molecular orientation and resultant fibrillation of TLCP. The compositional moduli of as-spun blend fibers were well fitted to the additivity rule of mixtures, viz., the Tsai-Halpin equation for the reinforcement of infinite aspect ratio.KEY WORDS Polysulfone / Vectra A-950 / In-Situ Composite / Blend / As-Spun Fiber / Rheology / Physical Properties / It has long been a subject of significant commercial importance for most polymer engineers to improve the thermal and mechanical properties of organic polymers. The ways to achieve this improvement in properties include synthesis of new polymers by molecular design, blending and alloying of existing polymers, and compounding a polymer with inorganic fillers or reinforcements. For the economical and practial reasons, an incorporation of inorganic materials has been widely adopted and has been commercially successful. However, inclusion of inorganic material component frequently brings about some serious problems during the fabrication process and the service period. Abrasion of processing equipments, flow instabilities resulting from high melt viscosities, and nonuniform product properties due to poor dispersion and poor interfacial adhesion, to name a few.t To whom all correspondence should be addressed.Recently, the in-situ reinforcement process based on the in-situ crystallization concept gives a promising clue to solve some of these problems. i -3 Kiss 4 has succeeded in avoiding such problems by adopting an in-situ composite technology, viz., by forming the reinforcing 1347 S. M. HONG et al. species in the matrix polymer on the spot during the fabrication process. Some fascinating advantages of this in-situ composite over the conventional inorganic reinforced thermoplastic composites are; a much enhanced processability due to the low melt viscosities, uniform product properties resulting from better dispersion of reinforcements, and less equipment damage. Further, the detrimental mechanica...

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“…[1][2][3][4][5][6][7][8][9] This is due to melt There is a growing interest in the research of polyblends containing liquid crystalline polymers viscosity reduction resulting from the addition of small amounts of LCP. In addition, the LCPs can (LCPs) and thermoplastics.…”

Section: Introductionmentioning

confidence: 99%

Rheology and impact characteristics of compatibilized polypropylene-liquid crystalline polymer composites

Tjong

1998

J. Appl. Polym. Sci.

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Polypropylene-liquid crystalline polymer (PP/LCP) and maleic anhydride compatibilized PP/LCP blends were prepared using the extrusion technique followed by injection molding. The LCP employed was Vectra A950 which consists of 25 mol % of 2,6-hydroxynaphthoic acid and 75 mol % of p-hydroxybenzoic acid. The rheology, morphology, and impact behavior of compatibilized PP/LCP blends were investigated. The rheological measurements showed that the viscosity of LCP is significantly higher than that of the PP at 280ЊC. This implied that the viscosity ratio of the LCP to the polymer matrix is much larger than unity. Scanning electron microscopy (SEM) observations revealed that the LCP domains are dispersed mainly into elongated ellipsoids in the PP/LCP blends. However, fine fibrils with large aspect ratios were formed in the compatibilized PP/LCP blends containing LCP content ¢ 10 wt %. The development of fine fibrillar morphology in the compatibilized PP/LCP blends had a large influence on the mechanical properties. The Izod impact strength of the PP/LCP blends showed little dependence on the LCP concentrations. On the other hand, the impact strength of the compatibilized PP/LCP blends was dependent on the LCP concentrations. The correlation between the LCP fibrillar morphology and spherulitic structure with the impact properties of the compatibilized PP/LCP blends is discussed.

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Characterization of liquid crystalline polyester polycarbonate blends

Cited by 117 publications

References 19 publications

Phase Diagram for Liquid Crystalline Polymer/ Polycarbonate Blends

Phase Diagram for Liquid Crystalline Polymer/ Polycarbonate Blends

Rheology and Physical Properties of Polysulfone in-situ Reinforced with a Thermotropic Liquid-Crystalline Polyester

Rheology and impact characteristics of compatibilized polypropylene-liquid crystalline polymer composites

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