Solid State Poly condensation

Ravindranath and Mashelkar 121 Unsteady state Solid-state poly condensation Particle... 

Mallon and Ray 123 Continuous Solid-state poly condensation Tube reactor... 

Reclaimed PET material is either directly upgraded by solid-state poly condensation [118] or repelletized before SSP [119]. In either case, the energy consumption can be reduced by eliminating an additional drying step if the downstream... 

Gostoli, C., Pilati, F., Sarti, G. C. and Di Giacomo, B Chemical kinetics and diffusion in poly(butylene terephthalate) solid-state poly condensation experiments and theory, J Appl. Polym. Sci., 29, 2873-2887 (1984). 

Tensile strength enhancement of PET and PBT for strapping applications without the need for solid-state poly condensation... 

The strategy of Kaeriyama represents a so-called precursor route and was developed to overcome the characteristic shortcomings (insolubility, lack of process-ability) of previous PPP syntheses. The condensation reaction is carried out with solubilized monomers, leading to a soluble polymeric intermediate. In the final reaction step this intermediate is then converted, preferentially in the solid state allowing the formation of homogeneous PPP films or layers, into PPP (or other poly(arylene)s). 

The chemistry of the solid-state polycondensation process is the same as that of melt-phase poly condensation. Most important are the transesterification/glycolysis and esterification/hydrolysis reactions, particularly, if the polymer has a high water concentration. Due to the low content of hydroxyl end groups, only minor amounts of DEG are formed and the thermal degradation of polymer chains is insignificant at the low temperatures of the SSP process. 

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. 

While all previous examples employ enzymatic ROP, there are two reports on block copolymer synthesis employing enzymatic poly condensation. The first one was published by Sharma et al. and describes the synthesis and solid-state properties of polyesteramides with poly(dimethylsiloxane) (PDMS) blocks [21]. The polycondensation was carried out with various ratios of dimethyl adipate. 

In a later study, Grenier-Loustalot et al. [40] examined the reaction of monoacids and monoamines as models for the condensation reaction. Peaks due the acid and amide were resolved in the solid-state NMR spectra, however, the linewidths in the spectra of these model compounds were appreciably smaller than those expected for the conformationally-complex poly(amic acid). In this paper, the authors used HPLC and FTIR to determine the effect of size and basicity of the amine, as well as the removal of water on the kinetics of reaction. Full imidization was achieved only on the addition of catalysts to the reaction mixture. 

NMR spectroscopy and in particular solid-state NMR spectroscopy proved to be a powerful method for studying the mechanism and extent of reaction in complex poly(imide) materials. In particular, during the cure of BMI resins, careful use of C CPMAS NMR indicated that measurements of the extent of cure by DSC were significantly overestimated [86, 87]. This article demonstrates that NMR spectroscopy has been able to characterize the structure of condensation poly(imide)s and, more successfully, the cure of BMI, PMR and acetylene-terminated resins. 

Polythionates contain ions of type [8 Og] and may be prepared by condensation reactions such as those in scheme 15.114, but some ions must be made by specific routes. Poly-thionate ions are structurally similar and have two 8031-groups connected by a sulfur chain (15.56 shows [8505] ) solid state structures for a number of salts show chain conformations are variable. In aqueous solution, polythionates slowly decompose to H28O4, 8O2 and sulfur. 

Droscher, M. and Wegner, G., Poly(etliylene terephtlialate) a solid state condensation process. Polymer, 19, 43-47 (1978). 

In the second stage the poly(amic acid) is cyclized in the solid state to the polyimide by heating at moderately high temperatures above 150°C. A different approach, avoiding the intermediate poly(amic acid) step, was pioneered by Upjohn. The Upjohn process involves the self-condensation of the isocyanate of trimellitic acid, and the reaction by-product is carbon dioxide (Figure 4.19b). 

NMR spectroscopy is a most effective and significant method for observing the structure and dynamics of polymer complexes both in solution and in the solid state. The widest application of NMR spectroscopy is in the field of structure determination. The identification of certain atoms or groups in a molecule as well as their position relative to each other can be obtained by one-, two-, and three-dimensional NMR. Information about the local dynamics, molecular and supramolecular organization, and the counterion condensation can be obtained. The counterion condensation and polyelectrolyte complexation between TEAC in poly(acrylic acid) was studied by Ni using C NMR. 

---