Martine Tessier

Synthesis and characterization of poly(copolyethers-block-polyamides) II. Characterization and properties of the multiblock copolymers

Abstract Multiblock copolymers were synthesized from an α,ω-dicarboxy-oligododecanamide (PA12dC; M n =2095) and various α,ω-dihydroxy-polyethers ( M n =1000–2000), especially, as copolyethers containing both polyoxyethylene and polyoxypropylene blocks. The polycondensation reaction was carried out in bulk at high temperature in the presence of Zr(OBu)4 as catalyst. A kinetic study permitted one to compare the reactivity of the different oligoethers used with respect to PA12dC. The thermal properties, the structure and morphology of these poly(polyethers-block-polyamides) were characterized by DSC, TGA, DMA and solid-state 13C NMR. DSC and DMA results show that the multiblock copolymers based on copolyethers exhibit a very high degree of phase separation and these soft blocks do not crystallize, whatever their length and composition. NMR results reveal that the crystalline polyamide phase adopts a structure (γ-form) similar to that of the oligoamide precursor.

Investigation of anisotropic epoxy–amine thermosets synthesised in a magnetic field

Bis{4‐[2‐(2,3‐epoxypropyl)ethoxy]benzoate}‐1,4‐phenylene and bis[4‐(2,3‐epoxypropoxy)benzoate]‐methyl‐1,4‐phenylene liquid crystalline diepoxy monomers were crosslinked with various diamines in a magnetic field. X‐ray scattering was used for mesophase identification and to determine the nematic order parameter of the resulting thermosets, which were cured under various temperature and magnetic field strength conditions. All thermosets exhibited nematic or smectic A (SmA) mesophases. The thermosets obtained from aliphatic diamines exhibited a very low degree of orientation. This phenomenon was assigned to their high reactivity, inducing a very fast crosslinking reaction that prevents the alignment of the mesogens. On the other hand, very high degrees of orientation along the magnetic field axis were observed for the SmA thermosets. In this case, the smectic period was smaller than the length of the epoxy monomer unit, which might be due to a staggered packing of the mesogenic cores. Negative longitudinal thermal expansion coefficients were measured below and above the glass transition temperature for the materials cured in a magnetic field.

Synthesis of mono and difunctional oligoisobutylenes

SummaryA complete quantitative structural analysis of α, ω-dichlorooligoisobutylenes is carried out. It appears that, in fact, two kinds of end groups are present : 70 % of these are separated from inifer by a “long” polyisobutylene chain ; the other 30 % are directly linked to the inifer molecule. These results were obtained by H-NMR analysis of the unsaturated oligomers resulting from a dehydrochlorination of the chlorinated oligomers.

Synthesis of mono and difunctional oligoisobutylenes: 1. Synthesis of mono and dichlorooligoisobutylenes

Summaryα-chloro et α Ω dichlorooligoisobutylenes (n

Synthesis of α-phenyl-ω-anhydride oligoisobutylene and α,ω-dianhydride oligoisobutylene

overline {Mn}

Synthesis and characterization of poly(copolyethers-block-polyamides). I. Structural study of polyether precursors

n in the range 1000–3000) have been prepared according to Kennedys classical method.13C NMR spectra of these oligomers have been registered and analyzed.

LIVING CARBOCATIONIC OLIGOMERIZATION OF ISOBUTYLENE BY TERTIARY ALCOHOL/BCl3/1-METHYL- 2-PYRROLIDINONE INITIATING SYSTEMS. KINETIC STUDY

An aliphatic-aromatic copolyester of poly(ethylene terephthalate), PET, and poly(ethylene adipate), PEA, PET-co-PEA, was synthesized by the high temperature melt reaction of post-consumer PET and PEA. As observed by NMR spectroscopy, the reaction yielded random copolyesters in a few minutes through ester-interchange reactions, even without added catalyst. The copolyesters obtained in the presence of a catalyst presented higher intrinsic viscosity than that obtained without the addition of catalyst, due to simultaneous polycondensation and ester-interchange reactions. The structure of the aliphatic-aromatic copolyesters obtained in different PET/PEA ratio is random as observed by NMR analysis.

Synthesis and characterization of new polyamides derived from di(4-cyanophenyl)isosorbide

Abstract The reaction of maleic anhydride with α-phenyl-ω-(2-methyl-2-propenyl) oligoisobutylene results in the formation of α-phenyl-ω-anhydride oligoisobutylene with an anhydride functionality up to 0.95. Before reacting maleic anhydride with α,ω-di(2-methyl-2-propenyl) oligoisobutylene, it is necessary to precipitate the initial α,ω-dichloro-oligoisobutylene in acetone to remove most of these short chains leading to side reactions, and thus to obtain a functionality close to two for the final product.