Pseudo poly urethanes

The miscibility between poly (vinyl chloride) and poly-urethanes based on poly (oxytetramethylene) glycol can be improved by introducing opposite charge groups to form ionic bonds. The improvement in miscibility from ionic bonds between the two polymer systems provided the best chance for interpene-tration between the linear chains of VMCC and the PU networks in order to obtain good physical properties of the ionomer pseudo-IPN coatings from PU and VMCC. 

Applications of Ester-Based "Pseudo" 12.6 Urethane-Based "Pseudo" Poly(Amino Acids) 213... 

URETHANE-BASED "PSEUDO" POLY(AMINO ACIDS)... 

The basic reaction scheme for formulating urethane-based pseudo poly(amino acids) requires a reaction of a diisocyanate with a diol in the presence of stannous oc-toate as a catalyst. Depending on their properties, either the diol or the diisocyanate could serve as the hard segment (h) or soft segment (s) as reported in Table 12.4. Several poly(urethanes) also include a diol- or diamine-based chain extender to yield a higher molecular weight product. 

TABLE 12.4 " Pseudo" Poly(amino acids) Formulated with Urethanes ... 

Poly(Amino Acids) 210 12.6.1 Synthesis of Urethane-Based "Pseudo" ... 

Sartor et studied the DSC curve of IPN of composition 25% PU/75% PMMA. In contrast to usual observations, the Tg increased over a very broad temperature range, which is due to the distribution of relaxation time. Chen et al. studied pseudo IPNs of linear poly(carbonate urethane) and crosslinked polychloroprene. The single-phase morphology of this pseudo-IPN has been confirmed by DSC measurements. 

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