Amorphous region of the polymer

In these complexes, the cations coordinate with the oxygen atoms of the backbone and, under the influence of an electrical potential, they are transferred from an oxygen atom to another through the amorphous region of the polymer assisted by the segmental motion of the polymer backbone. 

Experiments pertaining to a new system for the application of bromine to flame retardant polypropylene and foamed polystyrene are described. The FR compound, ammonium bromide, is formed in the amorphous regions of the polymer phase by the interaction of bromine sorbed on the polymer and ammonia, sorbed subsequently. Gaseous nitrogen which is also produced, expands and brings about the rearrangement of the chains to produce a porous structure. The ammonium bromide produced is finely divided and imparts FR properties to the polymer. 

Here, Da is diffusion coefficient in the amorphous phase alone, oc is the volume fraction of crystalline polymer, and t is a scalar quantity that denotes the tortuosity of diffusional path of the solute. The value of Da may be estimated by the Peppas-Reinhart model if the amorphous regions of the polymer are highly swollen. This substitution yields... 

A polymer may be amorphous, crystalline, or a combination of both. Many polymers actually have both crystalline and amorphous regions, i.e., a semicrystalline polymer. The Tg is a transition related to the motion in the amorphous regions of the polymer [3,8,9], Below the Tg, an amorphous polymer can be said... 

The depression of the melting point of a polymer by the presence of small amounts of comonomer is described by Flory and Eby Flory suggested that the comonomer is relegated to the amorphous regions of the polymer, its presence thus reducing the extension of the crystalline regions. Flory s equation for the melting point depression caused by comonomer B in polymer A reads ... 

As shown in Figure 1.7 there is a decrease in the coefiicient of thermal expansion, a, to values lower than extrapolated from the polymer melt (dotted line). This results in the polymer having a lower density than would be predicted and there is thus a measurable free volume, Vf, which has an important bearing on the properties of the amorphous region of the polymer. This and the detailed analysis of the glass transition are considered after the molecular requirements for polymer crystallization and the structure of the crystalline region. 

PET depolymerization by aminolysis is based on the reaction with primary amines such as methylamine, ethylamine and ethanolamine.66 69 The degradation takes place at temperatures in the range 20-100 °C and the studies carried out show that the attack of the amine is located preferentially on the amorphous regions of the polymer, because it is difficult to achieve a total PET conversion. 

Hexane Extraction and Bromination. Some of the fluorescent enones are extractable from the amorphous regions of the polymer matrix by cold hexane (1,13). This prpcess enables us to perform a simple chemical test for the presence of unsaturation, i.e., bromination (18). Figure 4 shows the fluorescence excitation and emission spectra of the cold hexane extract of commercial polypropylene before and after treatment with bromine. After bromination there is a significant reduction in the fluorescence intensity, confirming the presence of unsaturation. A similar result was obtained on brominating a cold hexane extract of poly-4-... 

The rationale for this approach further involved the hypothesis that swelling in water occurs by virtue of water uptake in the amorphous regions of the polymers with network structure provided by relatively water-insensitive crystallites in the polymers. In this approach, vinyl trifluoroacetate was polymerized or copolymerized to provide highly syndiotactic thermoplastic polymeric intermediates that were converted to the corresponding syndiotactic PVA homopolymers or copolymers by solvolysis with mild nucleophilic reagents in media that were not solvents for both starting and end-product polymers. 

Additive concentration gradients are induced by the crystallisation process but would be expected to relax on subsequent annealing. In fact the gradients do relax to some extent but a stable gradient of uv absorption remains with the spherulite centre less absorbing than the boundary (10). This cannot represent a concentration change of the additive within the amorphous regions of the polymer so it must be due to a variation in the... 

The concentration of solvent A is related to the 61% amorphous region of the polymer, i.e., the ciystalline part is not influenced by sorption and is subtracted when determining Wb. 

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