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ABSTRACT Cyclic oligo(butylene 2,5-furandicarboxylate) and ɛ-caprolactone were copolymerized in bulk at 130-150 °C by enzymatic ring opening polymerization using CALB as catalyst. Copolyesters within a wide range of compositions were thus synthesized with weight-average molecular weights between 20,000 and 50,000, the highest values being obtained for equimolar or nearly equimolar contents in the two components. The copolyesters consisted of a blocky distribution of the ɛ-oxycaproate (CL) and butylene furanoate (BF) units that could be further randomized by heating treatment. The thermal stability of these copolyesters was comparable to those of the parent homopolyesters (PBF and PCL), and they all showed crystallinity in more or less degree depending on composition. Their melting and glass-transition temperatures were ranging between those of PBF and PCL with values increasing almost linearly with the content in BF units. The ability of these copolyesters for crystallizing from the melt was evaluated by comparative isothermal crystallization and found to be favored by the presence of flexible ɛ-oxycaproate blocks. These copolyesters are essentially insensitive to hydrolysis in neutral aqueous medium but they became noticeably degraded by lipases in an extend that increased with the content in CL units. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 290-299 [ABSTRACT FROM AUTHOR]

Renewable polyesters derived from a sugar alcohol (i.e., sorbitol) were synthesized by solvent-free polycondensation. The aim was to prepare linear polyesters with pendant hydroxyl groups along the polymer backbone. The performance of the sustainable biocatalyst SPRIN liposorb CALB [an immobilized form of Candida antarctica lipase B (CALB); SPRIN technologies] and the organo-base catalyst 1,5,7-triazabicyclo[4,4,0]dec-5-ene (TBD) were compared with two metal-based catalysts: dibutyl tin oxide (DBTO) and scandium trifluoromethanesulfonate [also known as scandium triflate, Sc(OTf)3]. For the four catalytic systems, the efficiency and selectivity for the incorporation of sorbitol were studied, mainly using 13C and 31P NMR spectroscopies, whereas side reactions, such as ether formation and dehydration of sorbitol, were evaluated using MALDI-TOF-MS. Especially the biocatalyst SPRIN liposorb CALB succeeded in incorporating sorbitol in a selective way without side reactions, leading to close-to-linear polyesters. By using a renewable hydroxyl-reactive curing agent based on l-lysine, transparent and glossy poly(ester urethane) networks were successfully synthesized offering a tangible example of bio-based coatings. [ABSTRACT FROM AUTHOR]

2,3-O-Methylene-L-threitol (Thx) is a cyclic carbohydrate-based diol prepared by acetalization and subsequent reduction of the naturally occurring tartaric acid. The structure of Thx consists of a 1,3-dioxolane ring with two attached primary hydroxyl groups. Two series of partially bio-based poly(butylene terephthalate) (PBT) copolyesters were prepared using Thx as a comonomer by melt polycondensation (MP) and solid-state modification (SSM). Fully random copolyesters were obtained after MP using mixtures of Thx and 1,4-butanediol in combination with dimethyl terephthalate. Copolyesters with a unique blocklike chemical microstructure were prepared by the incorporation of Thx into the amorphous phase of PBT by SSM. The partial replacement of the 1,4-butanediol units by Thx resulted in satisfactory thermal stabilities and gave rise to an increase of the Tg values, this effect was comparable for copolyesters prepared by MP and SSM. The partially bio-based materials prepared by SSM displayed higher melting points and easier crystallization from the melt, due to the presence of long PBT sequences in the backbone of the copolyester. The incorporation of Thx in the copolyester backbone enhanced the hydrolytic degradation of the materials with respect to the degradation of pure PBT. [ABSTRACT FROM AUTHOR]

A set of linear polyurethanes containing isosorbide units were synthesized by polymerization in solution from HDI and MDI diisocyanates and 1,4-butanediol (BD), isosorbide (Is) or diisosorbide diurethanes (Is2HDI and Is2MDI) as diols. The thermal transitions, thermal stability, and crystal structure of the polyurethane homopolymers and copolymers containing isosorbide were evaluated and compared with those displayed by their polyurethane analogues entirely made of BD. It was found that incorporation of Is units in the polyurethane chain produced significant changes in T g, T m, and T d but no significant differences were noticed between copolymers made from Is or Is2 monomers. Degradation assays revealed that the presence of Is units increased slightly the hydrolysis rate of polyurethanes. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 [ABSTRACT FROM AUTHOR]

A set of polyurethanes containing isosorbide units were synthesized by polymerization in solution from HDI and MDI diisocyanates and 1,4-butanediol (BD), isosorbide (Is) or diisosorbide diurethanes (Is2HDI and Is2MDI) as diols. The thermal properties and stability, and crystal structure of the polyurethane homopolymers and copolymers containing isosorbide were evaluated and compared with those of the polyurethane analogues entirely made of BD. Incorporation of isosorbide produced significant changes in Tg, Tm and Td but no noteworthy differences were found between copolymers made from Is or Is2 monomers. Degradation assays revealed that incorporation of Is units increased slightly the hydrolysis rate. [ABSTRACT FROM AUTHOR]

The article presents information on a study which compared the effect of the preparation method and composition on the structure and some properties of new thermoplastic segmented poly(ester-urethane)s, whereby the hard segment is made of D-glucitol-derived extenders. A review of the related literature is given. Diisocyanates used for the synthesis were 1,6-hexamethylene diisocyanate (HDI) or 4,4'-methylene-bis(phenyle isocyanate) (MDI). A detailed discussion on the findings is presented.

Abstract: Poly(hexamethylene terephthalate) (PHT)/carbon nanotubes (CNT) nanocomposites containing 1% and 3% (w/w) of filler were prepared by two procedures: in situ ring-opening polymerization of hexamethylene terephthalate cyclic oligomers in the presence of CNT and melt blending of PHT/CNT mixtures. Arc discharge multiwalled carbon nanotubes, both pristine (MWCNT) and hydroxyl functionalized (MWCNT-OH), were used. The objective was to evaluate the effect of preparation procedure, nanotube side-wall functionalization and amount of nanotube loaded on properties of PHT. All nanocomposites showed an efficient distribution of the carbon nanotubes within the PHT matrix but interfacial adhesion and reinforcement effect was dependent on both functionalization and nanotubes loading. Significant differences in thermal stability and mechanical properties ascribable to functionalization and processing were observed among the prepared nanocomposites. All the prepared nanocomposites showed enhanced crystallizability due to CNT nucleating effects although changes in melting and glass transition temperatures were not significant. [Copyright &y& Elsevier]

Cyclic oligomers of isomannide 2,5-furandicarboxylate were synthesized using the high dilution condensation method. A mixture of dimer, trimer, and tetramer species largely enriched in dimer was obtained. These cyclic oligomers were made to react with oligo(butylene 2,5-furandicarboxylate) in bulk at 220 °C by ring opening polymerization using Sn(Oct)2 as a catalyst. A series of random poly(butylene 2,5-furandicarboxylate) copolyesters containing isomannide in a range of 5-50 mol % and with weight-average molecular weights between 30,000 and 50,000 g·mol-1 were prepared. These copolyesters started to decompose above 300 °C, and only those containing less than 10 mol % of isomannide showed signs of crystallinity. They displayed glass-transition temperatures in the 40-100 °C range with values increasing steadily with the content in isomannide. At difference with poly(butylene 2,5-furandicarboxylate) homopolyester that is reluctant to undergo hydrolysis, the isomannide-containing copolyesters were noticeably degraded by water, much more rapidly when exposed to lipases. [ABSTRACT FROM AUTHOR]

Bio-based triblock copolyesters were synthesized by ring-opening polymerization of l -lactide in solution using a hydroxyl-ended polytartrate as di-functional macroinitiator. This telechelic polyester with a M n about 3000 g·mol −1 was obtained by non-stoichiometric melt polycondensation of dimethyl 2,3-di- O -isopropylidene- l -tartrate and 1,4-butanediol. Two symmetrical triblock copolyesters with M n in the 5000–7000 g·mol −1 range and differing in the length of the polylactide blocks were prepared. The protecting isopropylidene group was removed in trifluoracetic acid to generate amphiphilic triblock copolyesters bearing free hydroxyl groups in the central block. All copolyesters started to decompose approximately at 260–280 °C, were semicrystalline, and readily degraded by hydrolysis of the main chain under both acid and basic conditions. The acetalized copolyesters had a single T g , whereas free-hydroxyl bearing copolyesters showed two T g indicative of blocks phase separation. All copolyesters were able to form nanoparticles with average diameters within the ~200–450 nm range. The influence of the block lengths and protection/deprotection of the hydroxyl groups on size and ζ -potential of the nanoparticles was evaluated. [ABSTRACT FROM AUTHOR]

Abstract: Poly(styrene-co-p-tert-butyldimethylsilyloxystyrene) copolymers, P(S/p-TBDMSOS), with contents in the substituted comonomer within the 0–50% range were prepared using combined Ph2Zn–CpTiCl3–MAO initiator systems and some of them were used as precursors of poly(styrene-co-p-hydroxystyrene), P(S/p-HOS), copolymers. p-tert-Butyldimethylsilyloxystyrene was synthesized from p-hydroxybenzaldehyde by protecting the hydroxyl group with tert-butyldimethylchlorosilane and converting the aldehyde group into vinyl through the Wittig reaction. The P(S/p-TBDMSOS) copolymers with contents in substituted units equal or higher than 25% were atactic and those with content higher than 5% were amorphous. P(S/p-HOS) copolymers containing up to 20% of hydroxylated units were obtained by full hydrolysis in acidic medium of the corresponding P(S/p-TBDMSOS). The hydroxylated copolystyrenes displayed crystallinity for the whole range of studied compositions and their crystalline structure was essentially similar to that of s-PS homopolymers. The influence of the substituent on the modified-MAO catalyzed copolymerization and on the thermal properties of the resulting copolymers was comparatively examined. [Copyright &y& Elsevier]

Abstract: Homopolymerization of α-olefins (1-C n H2n , n =6, 8, 10, 12, 16 and 18) and their copolymerization with styrene were carried out in toluene at 60°C using diphenylzinc–ethenylbisindenylzirconium dichloride–methylaluminoxane as initiator system. Atactic polystyrene and almost isotactic poly(α-olefin)s were obtained. Copolymerization of S/α-olefin with this initiator system gave isotactic olefin-enriched copolymers. According to DSC analysis, the homopolymers P(1-C12H24), P(1-C16H32), and P(1-C18H36) as well their styrene copolymers are crystalline. [Copyright &y& Elsevier]

A comparative study of the two isophthalic acid deriving homopolyesters poly(ethylene isophthalate) (PEI) and poly(ethylene 5-tert-butyl isophthalate) (PEtBI), including synthesis, crystal structure, and thermal and permeability properties, was carried out. The two polyesters were prepared by condensation polymerization in the melt. In both cases, minor amounts of cyclic dimers were observed to form, which were characterized by nuclear magnetic resonance and mass spectroscopy. PEI and PEtBI were thermally stable up to 400 °C and they appeared to be semicrystalline polyesters, having their melting temperatures between 130 and 135 °C. Their glass-transition temperatures were 62 and 94 °C, respectively. The crystal structure adopted by the two polyesters seemed to consist of a regularly folded conformation, clearly different from the almost extended conformation characteristic of poly(ethylene terephthalate). Gas permeability measurements for N2, O2, and CO2 revealed that PEtBI is more permeable to these gases than PEI, in spite of having a higher Tg. Furthermore, water vapor diffusion was found to be increased by the insertion of the tert-butyl group, whereas water absorption diminished. The differences in gas and water vapor transport properties observed for these two polyesters were discussed on the basis of their respective molecular structures. [Copyright &y& Elsevier]