The development of a new class of polyurethane polyols from cardanol, a renewable organic resource obtained as a byproduct of the cashew industry, is reported. For synthesizing polyols the monoglycidyl ether of cardanol was prepared first, followed by ring opening to prepare the diol or reaction with diethanol amine to give a triol. Alternately, another triol was also prepared by reaction of the glycerol monochlorohydrin with cardanol. Polyols having a range of hydroxyl values (140−265 mg of KOH/g) were prepared, and structure characterization was carried out by spectroscopic techniques. Polyurethanes were formulated by reaction of these polyols with diphenyl methanediisocyanate (MDI) at an NCO/OH ratio of 1, and films were characterized for thermal stability and viscoelastic properties by thermogravimetric analysis (TGA) and dynamic rheometry, respectively. The dynamic mechanical studies show a linear increase of the T g value with an increase in the hydroxyl value of the polyol. In TGA, when temperatures at 50% decomposition in nitrogen atmosphere are compared, polyurethanes based on diol and glycard indicate a higher thermal stability.

SYNOPSISPolyamic acids were synthesized from benzophenonetetracarboxylic &anhydride and diamines, viz., 4,4'-diaminodiphenyl methane and 4,4'-diaminodiphenyl ether. The course of imidization of the polyamic acids both by thermal and microwave treatments was tracked by infrared spectroscopy. The mechanical properties, namely the tensile strength and toughness of the films of polyimides with varying degree of imidization obtained by the two treatments were compared. The effect of degree of imidization of polyimide coatings on adhesion to copper substrate was also studied. Nearly 100% imidization was achieved by the thermal process, whereas the maximum imidization that could be achieved by the microwave process was about 50%. In thermal imidization, the adhesion values of the coatings slowly increased, attaining a maximum value at 80% imidization, after which there was a decrease in adhesion.

SYNOPSISN -(carboxymethyl) trimellitimide, the imidodicarboxylic acid, was prepared by the reaction between trimellitic anhydride and glycine. This was subsequently condensed in N-methyl-2-pyrrolidone with the alcoholysis products obtained from linseed oil and glycerine to get different oil length polyesterimide resins. The drying characteristics of the resins and the physicochemical properties of the clear and the iron oxide pigmented coatings were evaluated. The results indicate that these materials form a promising class of film-formers for coatings of good durability and protective properties.

SYNOPSISTwo monoimidodicarboxylic acids and four diimidodicarboxylic acids were synthesized from trimellitic anhydride and amino compounds, viz., glycine, p -aminobenzoic acid, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl methane, and 4,4'-diaminodiphenyl sulfide, and characterized by IR and 'H-NMR spectroscopies and melting-point determination. These functional monomers were condensed in N-methyl-2-pyrrolidone solvent with ethylene glycol by a transesterification reaction to obtain the novel polyester-imides with backbones of alternate imide-ester linkages or imide-imideester-ester linkages with -SOz-, -0-, -CHz-, or -S-Sbridges in between. All the polymers were characterized by IR and 'H-NMR spectroscopies, X-ray diffraction, solution viscosity, solubility and solubility parameters, and differential thermal analysis. Most of the polymers possess amorphous structure and fairly high decomposition temperatures (450-485°C). These polymers having solubility parameters in the range 6 11.44-11.85, as determined by the group contribution technique, are soluble at room temperatures in aprotic polar solvents.

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