Solid-state carbonation, polymeric

Gross, S. M. Roberts, G. W. Kiserow, D. J. DeSimone, J. M. Crystallization and Solid State Polymerization of Poly(bisphenol A carbonate) Facilitated by Supercritical C02. Macromolecules 2000, 33, 40 -5. 

X-Ray structures of bis(thiophenes) and bis[benzo(7)thiophenes] have been determined. In compounds 1,4-bis-(2-thienyl)butadiyne 34a, both the thiophene rings are disordered. Thus the position of sulfur and carbon atoms in thiophene rings, adjacent to the diacetylenic backbone, are interchangeable but with unequal occupations. The thiophene rings are planar and the dihedral angle between them is 65.6°. The diacetylene chains are inclined to the shortest axis, that is, the -axis, by 40.5°, and the perpendicular distance between the adjacent chains is 3.823 A, as against the respective values of 45° and 3.4 < Aj < 4.0 A, required for solid-state polymerization. 

Iyer, V.S. Sehra, J.C. Ravindranath, K. Sivaram, S. Solid-state polymerization of poly (aryl carbonates) a facile route to high-molecular-weight polycarbonates. Macromolecules 1993, 26 (5), 1186-1197. 

Bikiaris, D.N., Achilias, D.S., Giliopoulos, D., and Karayannidis, G.P. (2006) Effect of activated carbon black nanoparticles on solid state polymerization of polyfethylene terephthalate). Eur. Polym. /., 42, 3190-3201. 

Water and carbonated beverage bottles are made predominantly from poly(ethylene terephthalate) (PET). The polymer is made by condensation reaction of ethylene glycol with either terephthalic acid or its dimethyl ester. The process in practice includes three steps prepolymer formation, melt condensation to increase viscosity, and solid-state polymerization at 180-230°C to yield a resin with an average molecular weight that is high enough for use as bottle resins. Antimony trioxide is used as a catalyst in polymerization (Duh, 2002). 

A new polymerization technology for manufacturing polycarbonate has been established without using phosgene and methylene chloride (11,12). The new process, called Solid-state Polymerization Process , consists of three steps, namely, prepolymerization, crystallization, and solid-state polymerization (Figure 3). In die prepolymerization step, the amoiphous prepolymer is obtained by molten-state prepolymerization of bisphenol-A and diphenyl carbonate. The amorphous prepolymer is converted to the crystallized prepolymer in the crystallization step, and finally, in the solid-state polymerization step, the polycarbonate of Ae desired molecular weight is obtained. 

Solid-state Polymerization Step. The solid-state polymerization can be performed by heating the crystallized prepolymer at a temperature a little lower than its melting point under a flow of heated inert gas such as nitrogen, carbon dioxide, or lower hydrocarbons, or under reduced pressure (Figure 7). Since the surface area of the crystallized prepolymer is large, the rate of the solid-state polymerization is sufficiently fast Tht polymerization, therefore, can be easily carried out at a lower temperature, for example, 21O-220 C, in comparison to the melt process (280-3 lO C). Because the solid-state polymerization conditions are mild for the polycarbonate, the obtained polycarbonate is colorless and has several excellent properties. 

Solid-state polymerization of some diacetylenes proceeds via a biradical to give a backbone in which a triple and a double bond remain for each four-carbon repeat unit in the chain [21,22],... 

The reaction of dabco (l,4-diazobicyclo[2.2.2]octane) with Me2Cd yields a 1 1 adduct 197, which adopts a linear polymeric structure (Figure 34).255 The cadmium atom is coordinated by two dabco units and two methyl carbon atoms giving rise to a distorted tetrahedral environment. Finally, the organocadmium adduct 198 (Figure 35) has been isolated from the reaction of Me2Cd with Cd[(SeP-/-Pr2)2N]2.256 The solid-state structure consists of dimeric units where each methylcadmium unit is coordinated to three selenium atoms. The geometry about the cadmium center is tetrahedral with a Cd-C distance of 2.16 A, which is comparable to that observed in other cadmium alkyl complexes. 

We have previously reported the results of careful investigations of the solution carbonation (8) and oxidation (9) of polymeric organolithium compounds. These studies have been extended to the investigation of solid-state carbonation reactions and these results are reported herein. In addition, a new method has been developed for the synthesis of telechelic polymers with primary amine end-group... 

Amination (11) and solution carbonation (8) reactions were carried out as described previously. For solid-state carbonations, a benzene solution of poly(styryl)lithium was freeze-dried on the vacuum line followed by introduction of high-purity, gaseous carbon dioxide (Air Products, 99.99% pure). Analysis and characterization of polymeric amines (11) and carboxylic acids (8) were performed as described previously. Benzoyl derivatives of the aminated polystyrenes were prepared in toluene/pyridine (2/1. v/v) mixtures with benzoyl chloride (Aldrich, 99%). 

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