Ethylene naphthalene-2,6-dicarboxylate

Hodge, P Yang, Z Abderrazak, B.-H. A., and McGrail, C. S Cyclodepolymerization of poly(ethylene naphthalene-2,6-dicarboxylate) and ringopening polymerizations of the cyclic oligomers obtained, J. Mater. Chem., 10, 1533 (2000). 

Buchner, S., Wiswe, D. and Zachman, H. G., Kinetics of crystallization and melting behaviour of poly(ethylene naphthalene-2,6-dicarboxylate),... 

Figure 1.2. Typical microhardness values of polymers compared with data for metals. LDPE, low-density polyethylene HDPE, high-density polyethylene PA, polyamides POM, polyoxymethylene CEPE, chain-extended polyethylene CF-composite, carbon-fibre composite PS, polystyrene PEN, poly(ethylene naphthalene-2,6-dicarboxylate. (From Balta Calleja Fakirov, 1997.)...

Rueda et al. (1995), have followed the physical ageing of another glassy polymer. They investigated the variation in microhardness of poly(ethylene naphthalene-2,6-dicarboxylate) (PEN) stored in an ambient atmosphere for different times and after annealing at different temperatures below Tg for different periods of time. This material has stiffer molecules than PET due to the presence of a naphthalene ring instead of the benzene ring in the backbone chain. 

Ethylene naphthalene-2,6-dicarboxylate Single Tg T -depression NMR - Guo and Zachmann (1997)... 

Blending of poly(ethylene terephthalate) (PET) and poly (ethylene naphthalene-2,6-dicarboxylate) (PEN) has been shown to be an attractive possibility to combine the inherent economics of PET with the superior mechanical, thermal and barrier properties of PEN [24]. The molecular structure of PEN is stiffer than that of PET due to the presence in its main chain of naphthalene instead of benzene rings. The glass-transition temperature, Tg, of PEN is about 50° C higher than that of PET contributing to a better performance in terms of thermal, mechanical, and gas barrier properties [17,24]. PET and... 

Fig. 5.18 Plot of melting temperature against melt composition for random copolymers of ethylene terephthalate and ethylene naphthalene 2,6-dicarboxylate for different crystallization procedures. A dynamic crystallized sample A annealed sample fiber sample,...

Although PET and PBT are widely used, better thermal and mechanical properties are desired for some applications. Higher performance in semiaromatic polyesters was obtained from polyalkene naph-thalates. These semicrystalline polyesters are prepared by the condensation polymerization of naphtha-lene-2,6-dicarboxylic acid and flexible aliphatic diols. The naphthalene moiety imparts stiffness to the linear polymer backbone, leading to improved physical and mechanical, barrier, chemical resistance properties, and UV-ray screening performance. Poly(ethylene naphthalene-2,6-dicarboxylate), PEN, became commercially available from Teijin Ltd. in the early 1970s. PEN has a Tg and of 125 and 268°C, respectively [34]. Its structure appears in Fig. 1.18. 

Zhang, H. Ward, I.M. Kinetics of Hydrolytic Degradation of Poly(ethylene naphthalene-2,6-dicarboxylate.Mflcromo/ecM/e5. 1995, 28, 7622-7629. 

Kenwright AM, Peace SK, Richards RW, Bunn A, MacDonald WA. Transesterification in poly(ethylene terephthalate) and poly(ethylene naphthalene 2,6-dicarboxylate) blends the influence of hydroxyl end groups. Polymer 1999 40 5851-5856. 

Rueda RD, Varkalis A (1995) Water sorption/desorption kinetics in poly(ethylene naphthalene-2,6-dicarboxylate) and poly(ethylene terephthalate). J Polym Sci Part B Polym Phys 33 2263-2268... 

Statistical copolymers of ET and ethylene naphthalene -2,6-dicarboxylate (EN) units present yet another example of isodimorphic crystallization [86]. Both X-ray diffraction and thermal data, shown in Figure 11.9, indicate that as the concentration of ET units increases, the copolymer undergoes a crystal structure transition from... 

Here, i/gph is the hardness value of the spherulites, is the hardness of the amorphous interspherulitic regions, and is the volume fraction of crystallized spherulites. During primary crystallization, Hgph remains constant and hardness is directly proportional to the volume occupied by the spherulites (12). The hardness variation in the course of isothermal crystallization of PET and poly(ethylene naphthalene-2,6-dicarboxylate) (PEN) has been shown to follow Avrami law (13,14). 

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