Synthesis and Characterization of Decahydronaphthalene-Containing Polyesters

Abstract

Melt polycondensation of decahydro­naphthalate dimethyl ester with various diols enabled the synthesis of novel polyesters containing hydrogenated naphthalene rings. Decahydro­naphthalene-containing polyesters demonstrated thermal stabilities above 350 °C, and compression molding provided ductile, optically clear films. 1H NMR spectroscopy confirmed trans­esterification, and intrinsic viscosity measurements verified high molecular weights. Differential scanning calorimetry and dynamic mechanical analysis revealed structure–property relationships for glass transition temperatures (T g) and β-relaxations. Melt rheology examined the effect of chemical structure on flow behavior, and time–temperature superposition revealed two distinct transitions, which correlated to the T g and chain disentanglement. Furthermore, evaluation of the fractional free volume and flow activation energies suggested a structural dependence associated with regularity along the polymer backbone.

Rheological properties of HDPE and LDPE at the low-frequency range under supercritical CO2

“…Thus, it is feasible to use this method to characterize the viscosity in a high-pressure chamber given the small error in the low-frequency range. The effect of temperature on viscosity has been widely investigated using a conventional rheometer [31][32][33][34]. Although the plate geometry may lead to more accurate results, the rotor was selected in the high pressure chamber for the viscosity test in this work to maintain consistency with the geometry used in the latter characterization.…”

Influence of cyclobutane segments in cycloaliphatic decahydronaphthalene-containing copolyesters

“…5,6 Recently, our research group established a novel family of polyesters based on a fused cycloaliphatic monomer derived from dimethylnaphthalate as potential BPA-based polycarbonate replacements. 9 The isomeric mixture of the cycloaliphatic monomers prevented crystallization and generated optically clear polyesters. Although T g s remained below 100 C, dynamic mechanical analysis (DMA) revealed low-temperature relaxations that are ideal for high-impact resistance.…”

“…Earlier literature demonstrated the synthesis of dimethyl decahydronaphthalate-2,6-dicarboxylate from the hydrogenation of dimethyl naphthalate-2,6-dicarboxylate and enables direct incorporation into a melt-processable polyester family. 9,16,17 Complementary analytical techniques provide a detailed evaluation of structural effects on thermal and rheological properties. In addition, correlations between structure, entanglements, and free volume reveal important characteristics for target applications such as food packaging.…”

Amorphous copolyesters based on bibenzoic acids and neopentyl glycol

“…BPA PC ( T g = 145 °C), however, is well known for having excellent impact properties and has been the subject of many studies . Relaxations below the T g (often referred to as β‐relaxations) have come to be associated with good impact properties as an indication of short‐range molecular motions (e.g., phenyl ring flips and crankshaft motions) increasing free volume capable of absorbing energy during impact . CHDM is well known for enhancing the impact properties of (co)polyesters .…”

“…14,15,17,18,25,26 Relaxations below the T g (often referred to as β-relaxations) have come to be associated with good impact properties as an indication of short-range molecular motions (e.g., phenyl ring flips and crankshaft motions) increasing free volume capable of absorbing energy during impact. [27][28][29] CHDM is well known for enhancing the impact properties of (co)polyesters. 19 Improved impact properties of polyesters based on CHDM have been associated with increased sub-T g transition intensity in the vicinity if −60 C. 29 Comparison of crystalline and quenched amorphous samples of the same polyester have shown crystallinity to suppress β-relaxation intensity and shift it to higher temperatures due to restricted mobility.…”