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The optical and thermal properties of novel polyketanils (PKAX) with structures containing aliphatic and aromatic moieties are reported. It is demonstrated that the photoluminescence (PL) spectra can be modified not only by changing the ratio of conjugated to nonconjugated segment in the polymer main chain but also via acid−base doping involving the protonation of ketimine groups. By combining these two methods, it is possible to precisely tune the emission spectra of polyketanils in the spectral range of 435 to 550 nm. The most electron-rich molecule, PKA3, has the highest HOMO value of 2.26 eV. The protonation of the polymers changes the HOMO/LUMO energy gap of the polyketanils. Additionally, the photoluminescence spectra of the polyketanils in polymer blend with poly(methyl methacrylate) (PMMA) have also been described. The use of bifunctional protonating agent, containing plasticizing groups, for example the 1,2-(di-2-ethylhexyl) ester of 4-sulfophthalic acid (DEHEPSA), in addition to the modification of the luminescent spectra, leads to a lowering of the glass transition temperature and solubilization of the polymers studied. Soluble DEHEPSA complex with the aliphatic−aliphatic polyketanils in organic solvents facilitated their solution spectroscopic (¹H, ¹³C NMR, UV−vis, PL) characterization. The results of this study show that aliphatic−aromatic and aliphatic−aliphatic polyketanils are an interesting class of π-conjugated polymers whose electronic structure and properties can be regulated over a wide range by variation in main chain structure and through protonation or intramolecular hydrogen bonding.

Doping (protonation) of polyaniline (PANI) in the oxidation state of emeraldine with diesters of 4-sulfophthalic acid containing flexible alkyl or alkoxy substituents leads to flexible, partially crystalline polymeric conductors which show supramolecular organization of layered-type. Diesters doped PANI exhibits two glass transition temperatures Tg1 and Tg2 corresponding to the freezing of the movement of the dopant substituents and of the movements of polymer-dopant anion association, respectively. A strong thermochromic effect in the UV−vis−NIR spectra is observed at sub-Tg1 temperatures indicating increasing charge carriers localization. This thermochromic effect can be correlated with the σdc= f(T) relationship which unequivocally shows that at low temperatures (T < 100 K) the sample is in the insulating state which is another manifestation of the increasing localization of charge carriers.

A novel graft copolymer (PE-g-LCP) consisting of polyethylene (PE) backbones and liquid crystalline polymer (LCP) branches was synthesized via reactive blending of an acrylic acid-functionalized PE (Escor 5000 by Exxon) with a semiflexible LCP (SBH 1 : 1 : 2 by Eniricerche S.p.A.). The crude reactive blending product (COP) was shown by investigation of the fractions soluble in boiling toluene and xylene and of the residue to contain unreacted Escor and SBH, together with the graft copolymer forming the interphase. The compatibilizing activity of COP for PE/SBH blends, compared to that of pure Escor, was investigated using two PE grades. The COP addition into 80/20 PE/SBH blends caused a much stronger reduction of the SBH droplet dimensions and morphology stabilization than did that of pure Escor. The rheological behavior of the samples showed that COP leads to a slight increase of interfacial adhesion in the melt as well and that the effect is more pronounced when lower molar mass PE grade is used as the blend matrix. Melt-spinning tests demonstrated that deformation of the SBH droplets into highly oriented fibrils can be obtained for the blends of lower molar mass PE, compatibilized with small amounts of the novel PE-g-SBH copolymer. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2069–2077, 1999

The aim of this work was the synthesis of new graft copolymers consisting of polypropylene (PP) backbones and liquid crystalline polymer (LCP) branches, to be used as compatibilizing agents for PP/LCP blends. The PP-g-LCP copolymers have been prepared by polycondensation of the monomers of a semiflexible liquid crystalline polyester (SBH 1 : 1 : 2), that is, sebacic acid (S), 4,4'-dihydroxybiphenyl (B), and 4-hydroxybenzoic acid (H) in the mole ratio of 1 : 1 : 2, carried out in the presence of appropriate amounts of a commercial acrylic-acid-functionalized polypropylene (PPAA). The polycondensation products, referred to as COPP50 and COPP70, having a calculated PPAA concentration of 50 and 70 wt %, respectively, have been fractionated with boiling toluene and xylene, and the soluble and insoluble fractions have been characterized by Fourier transform infrared and nuclear magnetic resonance spectroscopy, scanning electron microscopy (SEM), differential scanning calorimetry, and X-ray diffraction. All analytical characterizations have concordantly shown that the products are formed by intricate mixtures of unreacted PPAA and SBH together with PP-g-SBH copolymers of different composition. Exploratory experiments carried out by adding small amounts of COPP50 or COPP70 into binary mixtures of isotactic polypropylene (iPP) and SBH while blending have demonstrated that this practice leads to an appreciable improvement of the dispersion of the minor LCP phase, as well as to an increase of the crystallization rate of iPP. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 391–403, 1998