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Abstract  

Phase transition behavior of polyesters derived from 2,7-phenanthrene dicarbonic acid diethylester and alkanediols with even methylene carbon number was investigated by the simultaneous DSC-XRD method. The smectic A phase was observed on cooling from the molten state. The transition entropy from the isotropic state to the smectic A phase was about 9.0 J mol-1 K-1, which depended on the methylene carbon number. The linear expansion coefficients, based on the (001) spacing of the crystalline phase at room temperature, were 1.310-4 K-1 (crystalline phase), 5.710-4 K-1 (crystallization region), 1.710-3 K-1 (smectic A phase) during cooling, and 1.510-4 K-1 (crystalline phase), and 1.010-3K-1(melting region) on heating.

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Introduction Unsaturated polyesters are low-molecular-weight maleate or fumarate esters containing various chemical structures designed for their specific coast and performance purposes [ 1 , 2 ]. The commonly used unsaturated

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interdisciplinary area involving chemistry, electrochemistry, metallurgy, environmental protection, and material science [ 1 , 2 ]. A much attraction of many researchers towards the polyesters has been noticed from the early days. The first polyester resin [ 3

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Abstract  

The thermal and crystal morphological properties of poly[ethylene teraphthalate] (PET) and poly(ethylene-2,6-naphthalenedicarboxylate) (PEN) biaxially oriented films were compared to amorphous and other isotropic semi-crystalline samples. Crystal melting as a function of temperature was characterized by temperature modulated DSC (TMDSC) and found to begin just above the glass transition for both oriented films. About 75°C above the glass transitions, substantial exothermic recrystallization begins and continues through the final melting region in oriented films. The maximum in the non-reversing TMDSC signal for the oriented films signifies the maximum recrystallization exothermic activity with peaks at 248°C and 258°C for PET and PEN, respectively. The final melting endotherm detected was 260°C and 270°C for PET and PEN, and is shown by the TMDSC data and by independent rapid heating rate melting point determinations to be due to the melting of species recrystallized during the heating scan. The results are compared with TMDSC data for initially amorphous and melt crystallized samples. The volume fraction of rigid species (F rigid=total crystal fraction plus rigid amorphous or non-crystalline species) were measured by TMDSC glass transition data, and contrasted with the area fraction of rigid species at the oriented film surface characterized with very high resolution atomic force microscopy (AFM) phase data. The data suggest that the 11 nm wide hard domains in PET, and 21 nm wide domains in PEN film detected by AFM consist of both crystal and high stiffness interphase species.

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Introduction Composites and their characterisation In spite of the fact that glass-fibre reinforced composite materials based on unsaturated polyester resins have been used for very long time [ 1 ] their

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new epoxy polyester materials. This paper presents the studies on the thermal and viscoelastic properties of novel epoxy-dicyclopentadiene-terminated polyesters-styrene copolymers. The influence of the structure of polyester and styrene content on the

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well-studied classical blends of two alike polymers, such as blends of polystyrene (PS) with poly(α-methyl styrene) (PαMS) [ 1 – 7 ]. Recently, biodegradable polyesters are finding increasingly more applications for environmental concerns. Their blends

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, 2 ]. In general polyester powder coating is a physical blend of lightly branched carboxyl-terminated polyester and triglycidyl isocyanurate (TGIC) and the curing take place through the reaction between hydroxyl of COOH and epoxy groups, which could

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Introduction Adding specific thermoplastic polymers as low profile additives (LPAs) in the unsaturated polyester resins (UP) is a well-known industrial technology. Such modified thermosetting polymers, essentially made from UP

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