Solid-state polymerisation process

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... 

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). 

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. ... 

On exposure to moisture, the crystalline anhydrides undergo an auto-accelerated polymerisation with evolution of carbon dioxide. This solid-state reaction proceeds without any observable change in the form of the crystal, and its effect on the X-ray pattern has been briefly investigated by Miller, Fankuchen and Mark (5). The probable mechanism of this process will be discussed later. 

The progress in the polymerisation of epoxides, which are considered to be very important heterocyclic monomers, concerns both mechanistic studies and technological studies aimed at commercialising certain epoxide polymerisation processes. Although wide studies have dealt with the catalyst structure, only a limited number of catalysts have been structurally determined in the solid state as well as in solution. The epoxide polymerisation mechanism, including stereochemical aspects, has been satisfactorily explained on the molecular... 

The list below gives a selection of the many polymer textbooks available. Some of these contain more about polymerisation processes and about polymers in solution and the melt than the present book, but their coverage of polymers in the solid state is often rather narrower. All are at a similar or slightly more advanced level than the present book, with the exception of (1). Although it is now quite old, this elementary book can profitably be read cover to cover by the complete beginner. 

In the case of semi-crystalline polymers, reports can be found on a two-step process in which short chains are crystallised after which the polymerisation is continued in the solid state to obtain, e.g., high-molecular-weight PLLA [19]. In this process, an inert gas stream is applied to remove by-products from the surface. The coupling mainly takes place in the amorphous regions of the materials, where the reactive end groups reside. 

The crosslinking/total polymerisation of the molecules via transformation of liquid resin into a hard solid state under the influence of heat. Cure refers to the completeness of the chemical reaction processes. 

The layman s term for the time/lemperature related molecular cross-linking process - known more correctly as polymerisation - which occurs when a thermoset resin changes from the typically viscous liquid to the solid state. This cure process is normally also promoted following chemical activation by a catalyst - or often called, hardener -addition. Other chemical accelerators may be added by the resin manufacturer, or alternatively added to the resin immediately prior to the catalyst addition. Cure can also be activated in other ways, such as by the influence of ultra-violet radiation. No by-products are formed during the formation of these long molecular cross-linked chain links. 

Upon the physical properties both in the solid state and in solution [2,3]. Furthermore, the macromolecular dimensions can be controlled since the synthesis involves a repetitive sequence of steps. Dendrimers are synthesised from monomers of the AB type (where X 3= 2) through a step-growth polymerisation process. 

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