Solid-phase polymerization

The most widely used method for preparing extended-chain crystals involves solid-phase polymerization when the monomer exists as a single crystal. The polymerization of single crystals of the monomer permits the preparation of a polymer material with a maximum orientation a polymeric single crystal composed of fully extended macromolecules. Such polymer crystals are needle-shaped22. ... 

Synthesis Solid-phase. Polymerization of N-protected a-amino acids (Fmoc or Boc). Solid-phase sub-monomer synthesis... 

Kibler, C., Process for solid phase polymerization of poly(ethylene tereph-thalate), Can. Patent 849 098, 1970. 

Huang, B. and Walsch, J. J., Solid-phase polymerization mechanism of poly(ethylene terephthalate) affected by gas flow and particle size, Polymer, 39, 6991-6999 (1998). 

Figure 5.4 Effect of gas flow rate on (a) the SSP reaction rate of PET at temperatures of 190 and 220 °C, and (b) the rate of increase of the intrinsic viscosity of PET at various temperatures [13]. Reprinted from Polymer, 39, Huang, B. and Walsh, J. J., Solid-phase polymerization mechanism of polyethylene tereph-thalate) affected by gas flow velocity and particle size, 6991-6999, Copyright (1998), with permission from Elsevier Science...

As mentioned earlier, both batch and continuous processes can be used to make PBT. Some manufacturers also incorporate solid-state or solid-phase polymerization (SSP or SPP, respectively) processes to increase molecular weight. 

As an additive to reduce the time necessary for solid-phase polymerization of PET and PBT resins... 

The second reaction, the formation of the polyester, is commercially conducted in the bulk melt phase with the removal of ethylene glycol to drive the reaction to high molecular weight. For higher molecular weights, PET can be solid-phase polymerized by again enhancing conditions to remove ethylene... 

Polymerization of thioacetone is also initiated by visible light. In fact, it has been shown that exposure of frozen crystals of thioacetone monomer to light leads to rapid solid phase polymerization (33). 

Polymer Production. Three processes are used to produce nylon-6,6. Two of these start with nylon-6,6 salt, a combination of adipic acid and hexamethylenediamine in water they are the batch or autoclave process and the continuous polymerization process. The third, the solid-phase polymerization process, starts with low molecular weight pellets usually made via the autoclave process, and continues to build the molecular weight of the polymer in a heated inert gas, the temperature of which never reaches the melting point of the polymer. 

IRACE AND RESIDUE ANALYSIS] (Vol 24) Solid-phase polymerization (SPP)... 

In the copolymerization of trioxane with dioxolane, reactivity ratios of dissolved copolymer cations are quite different from those of active centers in the crystalline phase. The former strongly prefer addition of dioxolane. The difference in reactivity ratios between dissolved and precipitated active centers is attributed to the fact that in the solid phase, polymerization and crystallization of the copolymer are simultaneous. The cationic chain ends are assumed to be directly on the crystal surface. Determination of the equilibrium concentrations of formaldehyde confirms this conclusion dissolved copolymer has a higher tendency to cleave formaldehyde than crystalline polyoxymethylene. In the latter stages of copolymerization the soluble copolymer is degraded gradually to the dioxolane monomer which is incorporated into the crystalline copolymer in an almost random distribution. 

Such differences in reactivities would be plausible if during chain growth in the solid phase, polymerization and crystallization were simultaneous. This means that a newly added monomer unit is incorporated into the crystal lattice at the same time that it is attached chemically to the polymer chain. This would imply that the cationic chain ends are directly on the crystal surface (simultaneous polymerization and crystallization as symbolized by Model A in Figure 2). 

To improve effectiveness of graft-polymerization and to decrease complexity of the lithography method, it is advantageous to use liquid or solid-phase polymerization strategies. One of the solving is to deposit a silicon-containing monomer onto a selectively exposed photoresist and then to heat it. The monomers will polymerize and an excess of them can be removed from the photoresist. The mask obtained can be used for the RIE in... 

Synthesis of Peptide, There is continual progress in the improvement of instruments and reagents for peptide synthesis, especially "solid phase polymerization" (90) (see Proteins). This method is suitable for the synthesis of peptides with 20 30 amino acid units. 

---