Aromatic diamine and phthaloyl chloride have been copolymerized using interfacial polymerization technique.Ethylene diamine (EDA) in 20, 30, and 40% and diamino butane (DAB) with the same molar ratio were used in addition to p-phenylene diamine to prepare polyamide with aliphatic components in the chain.The copolymers were characterized by FTIR Viscosity measurements were obtained in concentrated sulphuric acid.Thermogravimetric analysis and DrTGA showed that the thermal stability of the prepared polymers decreases by increasing of the ratio of the aliphatic diamines. The aliphatic content affects the crystallinity of the prepared polymers as was shown by X-ray diffraction measurements. Scanning electron microscopy revealed that the aliphatic components cause the copolymers to have a more homogeneous appearance with a different morphology. The mechanical parameters (Longitudinal modulus, L, shear modulus, G, Young's modulus, E, bulk modulus, K, and Poisson's ratio, p) were calculated from ultrasonic velocities and the densities of the isotropic materials. All mechanical characteristics were found to decrease with increasing aliphatic percent.
ABSTRACT:Curves of instantaneous copolymer composition vs. fractional conversion have been calculated for the copolymerization of N-vinyl-2-pyrrolidone (VP) with n-butyl acrylate (BA). Low conversion samples ofpoly(VP-ca-BA) possessing minimal heterogeneity in composition, were blended in appropriate proportions so as to simulate the cumulative copolymer compositions produced at various levels of conversion in an actual copolymerization. The phase behavior of these blends has been examined by electron microscopy. The results show that the miscibility between the copolymers within each blend is limited and is a consequence of the compositional heterogeneity predicted from the calculated curves. A morphological study for a series of blends of the homopolymers PVP and PBA was also effected and is discussed.
KEY WORDSScanning Electron Microscopy/ Poly(N-vinyl-2-pyrrolidoneco-n-butyl acrylate) / Copolymerization / Compositional Heterogeneity / Blends / Polymer Miscibility / Morphological studies of multiphase amorphous polymers by electron microscopy and often hindered by lack of contrast between the phases. Preferential-solvent etching techniques are usually employed to remove one phase selectively, and subsequently examine the topography of the blend. The authors are at present engaged in the study of polymer miscibility in blends during copolymerization for systems in which blending of polymers occurs simultaneously with their chemical formation, viz., the copolymerization of two monomers M 1 and M 2 to various levels of conversion.In previous publications 1 · 2 curves of instantaneous copolymer composition vs. fractional conversion C, were calculated for different initial feed mixtures contammg N-vinyl-2-pyrrolidone (VP) and n-butyl acrylate (BA) as monomers M 1 and M 2 , respec-* To whom correspondence should be addressed.tively. The values of the mole fraction/1 of VP in the feed were 0.821, 1 0.956, 1 and 0. 772 2 corresponding to 80, 95, 75 wt¾ VP in the feed, respectively. The values used for reactivity ratios r 1 and r 2 were 0.02 and 0.8, respectively.1·3·4 The compatibility within the blends of these systems assessed by light transmission, 1 glass transition behavior, 1 solution viscosity measurements, 2 and solubility parameters,2 was in reasonable accord with the compositional heterogeneity predicted from the calculated curves. The objective of the research presented herein is to explore the detailed morphology by electron microscopy and to gain a deeper insight into the phase behavior of the two systems comprising 80 and 95 wt¾ VP in the feed. These compositions are far from the azeotropic composition (/1 = 0.151 ), and hence, are selected here in order to provide reasonably wide ranges in the 435
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