The present document provides recommendations for (i) definitions of terms related to dendrimers with regular dendrons and to hyperbranched polymers, and (ii) nomenclature for naming these complex ...compounds on the basis of structure-based nomenclature for regular and irregular organic polymers, including adjustments required for specifying dendritic and hyperbranched macromolecular structures. The recommendations and the examples deal with organic-chemical structures only. Nevertheless, the general principles described in this document can similarly be applied to inorganic and to hybrid inorganic-organic dendrimers and hyperbranched macromolecules.
The influence of polyesters end-groups on cyclic oligoester formation is investigated using a series of hydroxy-, carboxy- and methylester-terminated aliphatic polyesters, in the presence of various ...ester interchange catalysts. The presence of hydroxy end-groups is the preponderant factor on cyclodepolymerization kinetics. This indicates that the main reaction is the intramolecular hydroxy-ester interchange reaction between hydroxy end-groups and ester functions in the chain. Carboxy-ester and ester-ester interchanges play a minor role, as the cycle-chain equilibrium is reached only very slowly when carboxy- or ester-terminated polyesters are reacted. High temperature and the presence of tin catalysts are also favorable factors, while, as expected, dilution shifts the equilibrium toward the formation of high yields of cyclic oligoesters. A mechanism is proposed, based on the reverse of the "coordination-insertion" mechanism established for the ring-opening polymerization of lactones.
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.
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•The synthesis of polyesteramides of ε-caprolactone and β-alanine is described.•Polyesteramide 1H and 13C NMR spectra are completely assigned.•Reaction mechanism is investigated with ...the help of model reactions.•The properties of random and quasi-alternating polyesteramides are compared.•The quasi-alternating polyesteramide presents higher modulus and tensile strength.
A series of random polyesteramides (PEAs) were obtained by direct reaction of ε-caprolactone and β-alanine in the melt and a quasi-alternating polyesteramide (degree of randomness=1.63) was synthesized by melt polycondensation of an intermediate hydroxy- and ethyl ester-terminated amide. Model reactions show that the reaction between ε-caprolactone and β-alanine proceeds first by the ring opening of ε-caprolactone by the amine groups of β-alanine. The random PEAs with ε-caprolactone contents equal to or higher than 60mol.% present a well-defined endotherm (Tm=29–56°C) corresponding to CL-rich polymer domains. On the other hand, random PEAs with ε-caprolactone content below 60mol.% present a broad melting zone (Tm=133–159°C) corresponding to ill-defined β-Ala-rich polymer domains. The quasi-alternating PEA (ε-caprolactone content of 50mol.%) presents a well-defined and large melting endotherm (Tm=92°C) and exhibits notably higher Young’s modulus and ultimate tensile strength than its random counterpart.
An easy and fast direct polyesterification method using Brønsted acid ionic liquids (
BAILs) as both reaction medium and catalyst was investigated. High molar mass polyesters of 12-hydroxydodecanoic ...acid (up to
M
w
¯
=
50
,
000
g
mol
−
1
) were obtained in good yields at atmospheric pressure and low temperature (90–130
°C) after 10–120
min reaction and without any added catalyst, reaction conditions that are much milder than conventional ones. Ionic liquids composed of an acidic cation bearing sulfonic acid groups and an acidic anion, such as 3-alkyl-1-(butyl-4-sulfonyl)imidazolium hydrogen sulfates, gave better results than ionic liquids containing only an acidic anion, such as 1-alkyl-3-methylimidazolium hydrogen sulfates. The 1/1
BAIL/12-hydroxydodecanoic acid molar ratio was found to yield polymers of the highest molar mass.
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