The Effect of Transreactions on the Structure and Dynamic Mechanical Properties of 1:1 Poly(ethylene terephthalate)/Poly(ethylene 2,6‐naphthalate) Blends Produced by Cryogenic Mechanical Alloying

Mano, João F.; Denchev, Z.; Nogales, Aurora; Bruix, Marta; Ezquerra, Tiberio A.

doi:10.1002/mame.200300045

Cited by 18 publications

(18 citation statements)

References 37 publications

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“…First of all, a sharper density drop is observed for the unground blend RW00 than for the ground one (GR00). Furthermore, in GR00 the density drop occurs at a cooling rate larger than that of the unground one, showing that crystallization is favored in blends where grinding of the pelletized components anticipates the melt blending, a result of the improved dispersion obtained by the smaller particle size, determining the homogeneity of the feed and providing better contact among the individual components …”

Section: Resultsmentioning

confidence: 99%

Influence of plasticizers and cryogenic grinding on the high‐cooling‐rate solidification behavior of PBT/PET blends

Poulose

Piccarolo

Carbone

et al. 2015

J of Applied Polymer Sci

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Two structurally different plasticizers (cyclic and linear) and the effect of cryogenic grinding on the solidification behavior at high cooling rates by a continuous cooling transformation approach of poly(butylene terephthalate)/poly(ethylene terephthalate), PBT/PET, blends are described. The solidification curve (density versus cooling rate) is confirmed as an effective tool to compare the differences in crystallization behavior under conditions mimicking processing. In comparison to the bulky cyclic plasticizer, the linear oligomeric one was found to have a more pronounced influence on the crystallization behavior. A 60/40 by weight PBT/PET blend shows a drop-off of density at 50 K/s. In the plasticized sample, the long-range crystalline order appears up to a cooling rate of 250K/s, making the blend comparable to pure PBT. Grinding the components before blending further improves crystallizability and synergy to the addition of the plasticizer. The results suggest the important role of local chain mobility in the solidification behavior at high cooling rates.

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Section: Resultsmentioning

confidence: 99%

Influence of plasticizers and cryogenic grinding on the high‐cooling‐rate solidification behavior of PBT/PET blends

Poulose

Piccarolo

Carbone

et al. 2015

J of Applied Polymer Sci

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“…TET triad is the original monomer of PET, whereas NEN triad denotes the original building block of PEN. Another triad NET, shown in this scheme, is supposed to be the block copolyester formed in‐situ in the interfacial region and can play a key role in compatibilizing the system 20…”

Section: Resultsmentioning

confidence: 99%

Correlation of Sequence Block Lengths and Degree of Randomness with Melt Rheological Properties in PET/PEN Blends

Khonakdar

Golriz

Jafari

et al. 2009

Macro Materials & Eng

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PET/PEN blends were prepared over the full composition range via a melt mixing process under various processing conditions. This resulted in transesterification reactions and formation of copolymer structures with various average sequence block lengths $(\bar L_{nPET} ,\;\bar L_{nPEN} )$ and degree of randomness (RD) determined by 1H NMR. It was seen that with an increase in time and temperature of mixing copolymer content (TEN%) and RD increased, whereas the $\bar L_{nPET}$, $\bar L_{nPEN}$ values were decreased. The differences in the extent of transreactions arising from different processing histories showed their systematic influence on rheological characteristics. Moreover due to progress of transreactions during the rheological measurements, convergence was seen in all the rheological characteristics at terminal zones in the high frequency regions. Similar convergence in the copolymer structural parameters was also obtained by NMR analysis. An increase in TEN% led to a systematic increase in viscosity of the blends. A decrease in the $\bar L_{nPET}$, $\bar L_{nPEN}$ values results in an increase in elasticity and relaxation time due to improvement of blend interface with increase in extent of copolymer formation.

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“…Another triad, NET, shown in this scheme, is supposed to be the block copolyester formed in situ in the interfacial region and can play a key role in compatibilizing the system. [18] Figure 1 NET, it is clearly seen that, with increasing mixing time, the extent of transesterification level becomes higher. The effect of mixing temperature on the transesterification level for PET/PEN 25/75 and PET/PEN 75/25 blends are presented in Figure 3 and 4, respectively.…”

Section: H Nmr Analysismentioning

confidence: 88%

An Improved Non‐Isothermal Kinetic Model for Prediction of Extent of Transesterification Reaction and Degree of Randomness in PET/PEN Blends

Golriz

Khonakdar

Jafari

et al. 2008

Macro Theory & Simulations

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An improved non‐isothermal kinetic model was developed based on mass balance and Arrhenius laws using a second‐order reversible reaction capable of predicting the extent of transesterification reaction (X) and the degree of randomness (RD) in poly(ethylene terephthalate) (PET)/poly(ethylene naphthalene‐2,6‐dicarboxylate) (PEN) blends prepared by a twin screw micro‐compounder over a full composition range under different processing conditions. The experimental values of X and RD were determined by 1H‐NMR and a direct relationship between them developed. The model constants were tuned by an optimization method using half of the experimental data, with the other half used for verification. Good agreement was found between the experimental and theoretical data in the verification stage and, therefore, it was concluded that the model is capable of predicting the extent of transesterification reaction with a high level of confidence for a wide range of processing conditions. Similarly to the experimental results, the model showed that, among all parameters affecting the extent of transesterification reaction, the time and temperature play the major role, whereas the blend composition does not have a significant role.magnified image

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The Effect of Transreactions on the Structure and Dynamic Mechanical Properties of 1:1 Poly(ethylene terephthalate)/Poly(ethylene 2,6‐naphthalate) Blends Produced by Cryogenic Mechanical Alloying

Cited by 18 publications

References 37 publications

Influence of plasticizers and cryogenic grinding on the high‐cooling‐rate solidification behavior of PBT/PET blends

Influence of plasticizers and cryogenic grinding on the high‐cooling‐rate solidification behavior of PBT/PET blends

Correlation of Sequence Block Lengths and Degree of Randomness with Melt Rheological Properties in PET/PEN Blends

An Improved Non‐Isothermal Kinetic Model for Prediction of Extent of Transesterification Reaction and Degree of Randomness in PET/PEN Blends

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