Hasmukh S. Patel

Poly(urethane-imide)s—1

Abstract Poly(urethane-imide)s (PUIs) were prepared by Diels-Alder (DA) reaction of 4-methyl-1,3-phenylene-bis(2-furanylmethylcarbamate) with bis(maleimides) e.g. N , N ′-ethylene bis(maleimide), N , N ′-1,4-phenylene bis(maleimide) and N , N ′-1,3-phenylene bis(maleimide). The DA reaction was carried out in 1,4-dioxane as solvent, as well as in bulk, followed by aromatization of tetrahydrophthalimide intermediates in the presence of acetic anhydride. All the polymers were characterized by elemental analyses, i.r. spectral studies and thermogravimetry. The PUIs exhibit moderate thermal stability. Preliminary tests for glass reinforcement of the PUIs indicate that laminates with good mechanical strength can be obtained.

Polyimides based on Poly(4-furanyl-butan-2-one):

Polyimides were prepared by Diels-Alder (DA) reaction of furfuralacetone (FAC) resin [poly(4-furanyl-butan-2-one)] with various bismaleimides. The DA reaction was carried out in tetrahydrofuran (THF) as solvent as well as in bulk, followed by aromatization of the tetrahydrophthalimide intermediates in the presence of acetic anhydride. All the polyimides were characterized by elemental analysis, IR spectral studies and thermogravimetry. The results show that polyimides based on FAC resin exhibit good thermal stability. Preliminary tests for glass reinforcement of the polyimides indicate that laminates with good mechanical strength can be prepared.

Novel Flame-Retardant Acrylated Poly(Ester-Amide) Resins Based on Brominated Epoxy

Bisphthalamic acids were prepared by reactions of phthalic anhydride and aromatic diamines. Novel flame-retardant poly(ester-amide) resins (FR-PEAs) were prepared by reactions of brominated epoxy resin (BER) with bisphthalamic acids using a base catalyst. The post reactions of these FR-PEAs were carried out with acryloyl chloride. The resultant products are designated as flame-retardant acrylated poly(ester-amide)s (FR-APEAs). The FR-PEAs and FR-APEAs were characterized by element analysis and number average molecular weight determined by nonaqueous conductometric titration. IR spectra for FR-PEAs and FR-APEAs were also carried out. The curing of these FR-APEAs was monitored on a differential scanning calorimeter (DSC) by using benzoyl peroxide as a catalyst. Glass fiber-reinforced composites of FR-APEAs have been fabricated and their chemical, mechanical, electrical and flame-retardant properties have been evaluated. The unreinforced cured samples of FR-APEAs were analyzed thermogravimetrically.

Glass-reinforced Polyimide Composites Based on Poly(2,5-furandiylmethylene)—III

A novel approach was used to develop a matrix resin for processable polyimide-glass-fibre composites. Furfuryl alcohol resin-poly(2,5-furandiylmethylene) and bismaleimides were polymerized (at 135 ± 10°C and 175 ± 10°C) by in situ Diels-Alder intermolecular reaction into moderately thermally stable and highly cross-linked polyimide-glass-fibre composites without the evaluation of by-products. The prepared composites (i.e. laminates) were characterized by their chemical resistance and mechanical properties.

Glass-reinforced Polyimide Composites based on Poly(4-furanyl-butan-2-one)

A novel approach was used to develop a matrix resin for processable poiyimide-glass-fibre composites. Furfural-acetone (FAC) resin, poly(4-Furanyl butan-2-one), and various bismaleimides were polymerized at 140 + 10 and 180+ 10+C by in situ Diels-Alder intermolecular reaction into moderately thermally stable and highly cross-linked polyimide-glass-fibre composites without the evolution oQf by-products. The fabricated composites (i.e. laminates) were characterized by their chemical resistance and mechanical properties

Polyimides Based on Poly(2,5-furandiylmethylene). II

Novel polyimides were prepared by the Diels-Alder (DA) reaction of furfuryl alcohol (FA) resin (poly(2,5-furandiylmethylene)), with various bis(maleimides). The DA reaction was carried out in tetrahydrofuran as solvent, as well as bulk, followed by aromatization of the tetrahydrophthalimide intermediates in the presence of acetic anhydride. All the polyimides were characterized by elemental analyses, IR spectral studies and thermogravimetry. The results show that polyimides based on FA resin exhibit moderate thermal stability. Preliminary results also indicate that glass fiber reinforced polyimide laminates show good mechanical properties.

Flame Retardant Unsaturated Poly(Ester Amide) Resins Based on Epoxy Resins

ABSTRACT Novel flame retardant unsaturated poly(ester amide) resins (FR-UPEAs) were prepared by the reaction of brominated epoxy resins (BER) with unsaturated aliphatic bisamic acids using a base catalyst. These FR-UPEAs were characterized by elemental analysis and number average molecular weight determination by non-aqueous conductometric titrations. The curing of these FR-UPEAs was carried out by using benzoyl peroxide (BPO) as a catalyst and was monitored on a differential scanning calorimeter (DSC). Based on DSC data, the glass fiber reinforced composites (i.e., laminates) of these FR-UPEAs have been fabricated and their chemical, mechanical, and electrical properties have been evaluated. The composites were analyzed for their self-extinguishing time. The unreinforced cured samples of FR-UPEAs resins were analyzed thermogravimetrically.

Polyimides Based on Furfuryl-Disulphide

Poly (disulphido-imides) were prepared by Diels-Alder (DA) reaction of furfuryl-disulphide (FDS) with various bismaleimides. The DA reaction was carried out in xylene as solvent, as well as in bulk, followed by aromatization of terrahydrophthalimide intermediates in the presence of acetic anhydride. All the poly (disulphido-imide)s were characterized by elemental analyses, IR spectral data and thermogravimetry. The poly (disulphido-imide)s exhibit moderate thermal stability. Preliminary test for glass reinforcement of the poly (disulphido-imide) indicate that laminates with good mechanical strength can be obtained.

Synthesis Characterization and Glass Reinforcement of Poly(urethane-imide)s-III

Poly(urethane-imide)s (PUIs) were prepared by the intermolecular Diels-Alder (DA) reaction of methylenedi-4,1-phenylenebis(2-furanyl-methylcarb-amate) (MPBFC) with various bismaleimides. The DA reaction was carried out in 1,4-dioxane as solvent as well as in bulk, followed by aromatization of tetrahydro-phthalimide intermediates in the presence of acetic anhydride. All the polymers were characterized by elemental analysis, IR spectral studies and thermogravfmetry. The PUts exhibit moderate thermal stability. MPBFC and bismaleimides were polymerized (at 145 + 10 C) by an in situ DA intermolecular reaction into moderately thermally stable PUls-glass fibre composite (i.e. laminates) and were characterized by their chemical resistance and mechanical properties.

Preparation and Chelating Properties of 4-Bromosalicylic Acid-Formaldehyde Polymers. Part II

Abstract 4-Bromosalicylic acid (BS) was condensed with various proportions of formaldehyde using different acid catalysts. The polymer samples have been characterized by IR spectral studies, by their number-average molecular weight (M n), and by TGA. Viscosity measurements of selected polymer samples in DMF showed that their solutions exhibited polyelectrolyte behavior. The intrinsic viscosity [η] of the polymer samples were measured in 80:20 (v/v) DMF/water containing 1% KBr, a medium in which the polymers exhibited normal behavior. Metal chelates of one polymer sample are characterized. Ion-exchanging properties of the same sample are studied by application of the batch equilibrium method