Macromol. Rapid Commun. 17/2011

Trzaskowski, Justyna; Quinzler, Dorothee; Bährle, Christian; Mecking, Stefan

doi:10.1002/marc.201190044

Cited by 11 publications

(17 citation statements)

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“…Pure long-chain polyesters (like PE 1 A 0 -53.6H) crystallize in the polyethylenelike orthorhombic structure (Figure 8, pattern A), since the ester groups are incorporated in the all-trans hydrocarbon crystal lattice as defects, resulting in reduced melting points and lower crystallinities compared to linear polyethylene. 29,70,73 With a substitution of ester groups for amide groups, a further increase in the interchain spacing is probable, compensating the additional cohesion energy arising from hydrogen bonding (which can also occur between amide and ester functionalities) and resulting in relatively constant peak melting points with still sharp melting transitions. The orthorhombic structure displaying 2θ angles of 21.4°and 23.8°is still maintained (B), but an enlarged amorphous halo is observed in the WAXD pattern of PE 0.76 A 0.24 -51.9H, together with a reduced heat of fusion.…”

Section: Macromoleculesmentioning

confidence: 98%

“…Here, ADMET copolymerization again provides an efficient method, when the amide containing diene monomer 1 previously used for polyamide preparation is randomly copolymerized with the ester functionalized diene 3 (prepared by condensation of 10-undecenol with 10-undecenoic 29,31,70,71 to full conversion (Scheme 3). By this approach, the different contributions to the cohesion energy by hydrogen bonding forming amide and less polar ester groups in hydrocarbon chains can be investigated, while the overall number of functional groups remains constant (ca.…”

Section: Macromoleculesmentioning

confidence: 99%

“…72 Different monomer ratios were copolymerized using HG2 as a catalyst precursor to yield unsaturated polyesteramides, while the homopolymerization of 3 yielded the unsaturated polyester for comparison (Table 4). 29,70 Saturated polymers were obtained by exhaustive carbon−carbon double bond hydrogenation as already described for polyamides. Molecular weight analysis by 1 H NMR spectroscopy and GPC revealed M n values above 10000 g mol −1 with polydispersities M w /M n around 2 for the polyesteramides and the ester homopolymer, while a significantly lower molecular weight and degree of polymerization were observed for the amide homopolymer (vide supra).…”

Section: Macromoleculesmentioning

confidence: 99%

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Long-Spaced Polyamides: Elucidating the Gap between Polyethylene Crystallinity and Hydrogen Bonding

2015

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Aliphatic polyamides with so far inaccessibly low amide contents were prepared by acyclic diene metathesis (ADMET) copolymerization of N-(undec-10-en-1-yl)undec-10-enamide (1) and undeca-1,10-diene (2) applying different Grubbs and Hoveyda−Grubbs type olefin metathesis catalyst precursors, followed by exhaustive postpolymerization hydrogenation to yield saturated copolymers. These polyamides, containing between 1.0 and ca. 50.5 amide groups per 1000 methylene units, fill the gap between polyamides from classical polymerization approaches, like polycondensation of diamines with diacids, and linear polyethylene. With reduced amide concentrations the melting points of polyamides converge toward polyethylene, passing through a distinct melting point minimum observed around 110°C for polyamides with ca. 35 amide groups per 1000 methylene units. The minimum goes in hand with a change in the crystal structure related to the different ratios of intersegment interactions from hydrogen bonding and nonpolar van der Waals forces depending on the amide group content in the crystalline state. Furthermore, the influence of hydrogen bonds between amide and ester groups has been quantified for polyesteramides with various amide/ester ratios, prepared by ADMET copolymerization of N-(undec-10-en-1-yl)undec-10-enamide (1) with undec-10-en-1-yl undec-10-enoate (3) and postpolymerization hydrogenation.

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Section: Macromoleculesmentioning

confidence: 98%

Section: Macromoleculesmentioning

confidence: 99%

Section: Macromoleculesmentioning

confidence: 99%

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Long-Spaced Polyamides: Elucidating the Gap between Polyethylene Crystallinity and Hydrogen Bonding

2015

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“…However, melting points are lower than 100°C and much lower than that of expected PE. Longer α, ω-dicarboxylic acid and α, ω-diol, consisting of 12-carbon chain (Figure 9), were synthesized via metathesis, hydrogenation, and reduction (61). Polycondensation of these monomers resulted in polyesters with melting point of 108°C.…”

Section: Polyestersmentioning

confidence: 99%

Lightweight Materials Prepared from Vegetable Oils and Their Derivatives

Hong

2014

ACS Symposium Series

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“…Some small counits, like ester groups, can be incorporated in the crystals without significantly changing the crystallinity. 5,6 Several routes have been explored for the synthesis of these types of polyesters using (combinations of) acyclic diene metathesis (ADMET), 7,8 polycondensation, 3,9,10 and thiol−ene chemistry 11 of (modified) fatty acids as well as ring-opening metathesis polymerization (ROMP) of unsaturated renewable macrolactones with cyclic olefins 6 and ringopening polymerization (ROP) of macrolactones. 12−14 The ROP of macrolactones, viz.…”

Section: ■ Introductionmentioning

confidence: 99%

Mimicking (Linear) Low-Density Polyethylenes Using Modified Polymacrolactones

et al. 2015

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This paper presents a new approach toward the introduction of both short-(SCB) and long-chain branching (LCB) in polyethylene-like polyesters via the ring-opening polymerization of macrolactones. Macrolactones containing an alkyl (S1) or alcohol (S2) branch were obtained using radical thiol−ene chemistry of ambrettolide (Amb). Kinetic studies revealed the need for an excess of thiol to achieve a high conversion of the double bond. Even though homopolymerization of the three monomers Amb, S1, and S2 revealed comparable reactivities, the molecular weight buildup during polymerization of S2 differs drastically from that of Amb and S1. Instead of the linear increase of M n with conversion observed for Amb and S1, the molecular weight buildup for the ring-opening polymerization of S2 resembles that of a step-growth polymerizationslow buildup at low and moderate conversion followed by a rapid increase in molecular weight at high conversions. This disparity was attributed to the possibility of S2 to function as both an initiator and a monomer, leading to oligomers during the first part of the reaction that are subsequently connected to each other at the final stage of the reaction. Copolymerization of pentadecalactone (PDL) with various ratios of Amb, S1, and S2 in bulk led to the associated random copolymers containing double bonds, short-chain branches, and long-chain branches. The trans-double bonds in poly(PDL-coAmb) are included in the crystal lattice, leading to a slight decrease in the melting temperature, melting enthalpy and yield stress, while up to 20 double bonds/1000 backbone atoms the crystallinity and lamellar thickness remain similar to those of polypentadecalactone. In contrast, SCBs are fully excluded from the crystal lattice, leading to a more significant decrease in melting temperature and enthalpy as well as crystallinity and lamellar thickness with increasing branching density. The stiffness of these SCB-copolymers exponentially decreases as a function of branching content, effectively changing the mechanical behavior from semicrystalline to elastomeric. The LCB-containing polymers show an even larger linear decrease in melting temperature with increasing branching density than their SCB equivalents, likely due to the particular topology of the polymers consisting of a brush to a hyperbranched structure. However, a rapid decrease of molecular weight as was observed upon increasing the S2 content is also likely to play a role. The observed low molecular weight can be ascribed to both the fact that (macrocycles of) S2 can function as initiator, effectively increasing the amount of polymer chains, and the change of molecular weight buildup.

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Macromol. Rapid Commun. 17/2011

Cited by 11 publications

References 0 publications

Long-Spaced Polyamides: Elucidating the Gap between Polyethylene Crystallinity and Hydrogen Bonding

Long-Spaced Polyamides: Elucidating the Gap between Polyethylene Crystallinity and Hydrogen Bonding

Lightweight Materials Prepared from Vegetable Oils and Their Derivatives

Mimicking (Linear) Low-Density Polyethylenes Using Modified Polymacrolactones

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