Solid state post condensation

Villain and co-workers [146] examined a wide variety of species for potential use as hydroxyl reactive end-cappers suitable for inclusion in PET to minimise acetaldehyde contamination of products. The purpose behind the study was to be able to use cheaper grades of PET for beverage bottles rather than the more expensive solid state post-condensation (SSP)-treated grades normally used (see Section 6.4.1). Best results, with the additives selected, were... 

Table 10.2 Technical parameters of continuous solid state post condensation...

Figure 14, PET solid state post-condensation, continuous processing...

Method of synthesis polyamide-4,6 Is a product of polycondensation oftetrameth-ylene-dlamlne and adipic acid. Due to the very high melting temperature the production of polyamide-4,6 was very difficult. As late as 1985 a process was invented to produce polyam-ide-4,6 on a commercially attractive scale in two step process Including precondensation and solid-state post-condensation ... 

Method of synthesis in the first step a low moleoular weight prepolymers with M =1000-2000 g mol" are synthesized to obtain a ooncen-trated aqueous solution of prepolymers after isolation of the prepolymers, the solid state post-condensation is performed at a temperature of about 35°C below the corresponding T until the desired moleoular weight is reached Koning, C Teuwen, L de Jong, R Janssen, G Coussens, B, High Perform. Polym., 11,387-94,1999. 

Besides in the liquid phase, some polyreactions are also performed in the solid state, for example, the polymerization of acrylamide or trioxane (see Example 3-24). The so-called post condensation, for example, in the case of polyesters (see Example 4-3), also proceeds in the solid phase. Finally, ring closure reactions on polymers with reactive heterocyclic rings in the main chain (e.g., poly-imides, see Example 4-20) are also performed in the solid state. 

Historically, the field of electronic structure calculations has seen two largely independent lines of development on the one hand molecular quantum chemists have based most work on wavefunction techniques (the Hartree Fock [2, 3] and post-HF theories [4]) on the other, condensed-matter physicists had their reference method in Density Functional Theory (DFT) [5-7]. This formal division between molecular and solid-state communities has been due to the poor transferability of the standard computational methods between the two fields early DFT functionals underperform post-HF techniques in reproducing the known properties of small molecules... 

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