Solid-state polymerisation

A method for the depolymerisation of PETP fibres using quarternary ammonium salt phase transfer catalysts in saponification processes at atmospheric pressure and temperatures as low as room temperature is reported. Terephthalic acid was produced in yields as high as 93%. Also reported are similar processes for the depolymerisation of nylon 66 and nylon 46 fibres. Nylon 46 oligomers produced were repolymerised using solid-state polymerisation to produce high molecular weight nylon 46. Nylon 66 was depolymerised to produce oligomers and adipic acid in reasonable yields. 11 refs. USA... 

During spontaneous solid-state polymerisation at 325°C/8-10 kbar, the acid... 

The solid state polymerisation of diacetylenes (2) with U.V. radiation, heating or shear force is most indicative of the predominant influence of electron-lattice coupling. The details of the chemical changes that occur during th polymerisation process are crucial (2,40) but the overall description only needs part of this chemical information. The kinetics and thermodynamics of the polymerisation process using an elastic strain approach have been worked out in (41). 

Another example of solid-state polymerisation is polymerisation of diacetylene derivatives which results in the formation of highly crystalline polymer that also conducts electricity. 

A notable case of solid-state polymerisation is that of diacetylenes giving rise to a special class of highly ordered conjugated polymers as follows ... 

We can then treat e as a scalar quantity, which is independent of the orientation of the electric field vector, as in Equation (2.6). This will not be true if the polymer has a preferred orientation conferred either by mechanical deformation or solid-state polymerisation. In this situation the relative permittivity will be a tensor so that... 

While the focus of current interest is on carbon backbone polymers, we should not overlook poly(sulphurnitride), see Section 4.2.6. SN is an electrically conductive inorganic polymer that becomes superconducting at low temperature (Labes et al., 1979). SNV is obtained as a single crystal material by the solid-state polymerisation of S2N2. Though S2N2 decomposes explosively at... 

The solid-state polymerisation of the diacetylenes can be initiated thermally and/or through irradiation with UV or y radiation and leads for many substituents R to macroscopic poly-diacetylene single crystals. For most substituents R, it is irreversible. Table 2.5 gives a selection of substituents R with which macroscopic diacetylene crystals have been successfully grown. Additional examples can be found in Enkelmann [11]. 

FTIR spectroscopy and near-infrared-FT-Raman spectroscopy were used to study the molecular stmctural transformations which occurred during thermal treatment of several nitroxyl substituted diacetylene monomers. These spectroscopic techniques were also used to investigate the solid state polymerisation reactions of the nitroxyl-substituted monomers, classic diacetylenes and of polydiacetylenes. The results were discussed. 7 refs. RUSSIA... 

Polycarbonates were earlier prepared by the polymerisation of phenols (e.g., bisphenol-A) using phosgene and methylene chloride. A new process has been developed by Asahi Chemical Industries using solid state polymerisation for producing polycarbonate without phosgene and methylene chloride. ... 

Solid state polymerisation of a-amino acids has been achieved giving rise to high molecular weight polypeptides. 

Synthesis of High Molecular Weight Polypeptides N-carboxy anhydrides of a-amino acids, viz. L-leucine, L-alanine, y-benzyl-L-glutamine and glycine undergo solid state polymerisation by using butylamine as an initiator in a hexane suspension at 20-50 C (Scheme 51). 

In the next stage, the product is heated up to the desired temperature for solid state polymerisation (e g. 215-240 °C), commonly with a large countercurrent nitrogen flow (fluidised bed or not) and the pol5mierisation is initiated. 

When the ehips leave the solid state polymerisation (SSP) reactor they are cooled and stored in a silo. The product is usually stored under nitrogen or dried air, as the PET chips are very hygroseopie and the presence of small traces of water would decrease the degree of polymerisation, especially during subsequent proeessing at elevated temperatures. 

Figure 10.4 Flow diagram of continuous solid state polymerisation...

Figure 1433, Schematic view of the solid-state polymerisation of the LB film of an amphiphilic pyrrole. (Reproduced by permission of Elevier Sequoia from ref. 245.)...

H. J. Spencer, R. Berridge, D. J. Crouch, S. P. Wright, M. Giles, I. McCulloch, S. J. Coles, M. B. Hursthouse, and P. J. Skabara. 2003. Further evidence for spontaneous solid-state polymerisation reactions in 2,5-dibromothiophene derivatives. / Mater Chem 13(9) 2075-2077. 

It has also been shown that in solid-state polymerisation of danol with poly(butylene terephthalate), PBT, the diol is not incorporated into the rigid fraction. The RAF was detected using DSC. The PBT chains in the rigid fraction are deemed too inflexible to take part in the transesterification reaction, in contrast to the chains in the mobile amorphous fraction [24]. The area of the RAF is one which may see significant development in food polymers, such as starch. 

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