Furans in polymer chemistry

Styrene copolymers containing various amounts of a novel comonomer bearing a pendant furan ring were synthesized and characterized before being submitted to Diels−Alder reactions with either a monomaleimide or a bismaleimide. Spectroscopic evidence, supported by data from model compounds, indicated that the resulting linear and cross-linked products contained extensive percentages of adduct structures formed from the furan moieties. Both types of materials were then heated in a solvent containing a large excess of 2-methylfuran in order to induce the retro-Diels−Alder and the coupling of the released maleimides with the furanic additive. The reaction proceeded as expected and the original copolymers could be recovered from the treatment. The interest in the general strategy reported here resides in the possibility of recycling cross-linked polymers by a simple thermal treatment conducted in the presence of a suitable trap.

Application of the Diels−Alder Reaction to Polymers Bearing Furan Moieties. 2. Diels−Alder and Retro-Diels−Alder Reactions Involving Furan Rings in Some Styrene Copolymers

▪ Abstract High-temperature polymers have found widespread use in aerospace and electronics applications. This review deals with recent developments in the chemistry of these materials that have led to improvements in processability and high-temperature stability.

Recent advances in the development of processable high-temperature polymers1

This study describes the synthesis of polyadducts formed by successive Diels-Alder reactions. The monomers used involved a bis-diene bearing two furan rings and two different bis-dienophiles, both containing terminal maleimide functions. Model compounds and reactions proved particularly useful for the establishment of the most adequate reaction conditions and for assessing the spectroscopic features related to the adduct structures. It was found that the mechanism of chain growth was not perturbed by detectable side reactions, but that polymers precipitated at an early stage of their development.

Diels-Alder polymerization of difurans with bismaleimides

Polyimides containing s-triazine ring

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.

Polyimides 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

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

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.

Polyimides Based on Furfuryl-Disulphide

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

Poly(imide)s based on furfuryl-disulfide

Poly(coumarin-urethane)s (PCUs) were prepared by the condensation reaction of 3,3'-dihydroxy-6,6'-methylcnebiscoumarin (DHMBC) with various diisocyanates. All the poly(coumarin-urethane)s were characterized by elemental analysis, IR spectral studies, number average molecular weight determination (by vapour pressure osmometry), viscosity studies and thermogravimetry.

Harshad D. Patel

Papers

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

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

Polyimides Based on Furfuryl-Disulphide

Poly(imide)s based on furfuryl-disulfide

Synthesis and characterization of poly(coumarin-urethane)s: