Crosslinked Polymers and Rubber Elasticity

doi:10.1002/0471757128.ch9

Cited by 11 publications

(9 citation statements)

References 66 publications

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“…In general, materials containing C4F9-PFPE-end-segments showed significantly lower wettability and surface energy than the oligomers having the same polyurethane chain, which was not terminated with the perfluoroalkyl short moiety. This superiority of materials containing C4F9groups can be expected, since the films' surface is always preferentially occupied by the fragments of the molecular chains with the lowest surface energy [7]. Indeed, CF3groups possess the lowest surface energy of ~6 mN/m.…”

Section: Wettability Of Fopusmentioning

confidence: 94%

“…Specifically, the midpoint T g is approximately 45 • C and T m is~125 • C. We connect these differences with the chemical structure of oligomers. HFOPUs possess more flexible aliphatic polyurethane segments in the backbone, while the presence of the rigid phenyl rings in MFOPUs increases their thermal transition temperatures [7,60,61].…”

Section: Synthesis and Characterization Of Fopusmentioning

confidence: 99%

“…We associate this phenomenon with higher density (and lower mobility) of the amorphous part of MFOPU-1 material, which is (in contrast to HFOPU-1) well below T g at ambient temperature. Indeed, according to the free volume theory of glass transition and experimental observations, T g is the iso-free-volume state of macromolecular materials, where all materials have approximately the same fractional free volume at the transition [7]. The volume coefficient of thermal expansion of polymers is about two times higher above T g than the one below T g .…”

Section: Water and Oil Repellency Of Hfopu-1 And Mfopu-1mentioning

confidence: 99%

“…Repellency has been one of the critical targets in designing practical polymer-based materials contacting with aqueous and/or oily liquid media [1][2][3]. To this end, a number of engineering thermoplastics have low wettability by water and demonstrate significant water repellency [4][5][6][7]. In contrast to hydrophobic polymers, only fluorinated polymers demonstrate some level of oil repellency [4,[8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

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Towards a Long-Chain Perfluoroalkyl Replacement: Water and Oil Repellent Perfluoropolyether-Based Polyurethane Oligomers

et al. 2021

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Original perfluoropolyether (PFPE)-based oligomeric polyurethanes (FOPUs) with different macromolecular architecture were synthesized (in one step) as low-surface-energy materials. It is demonstrated that the oligomers, especially the ones terminated with CF3 moieties, can be employed as safer replacements to long-chain perfluoroalkyl substances/additives. The FOPU macromolecules, when added to an engineering thermoplastic (polyethylene terephthalate, PET) film, readily migrate to the film surface and bring significant water and oil repellency to the thermoplastic boundary. The best performing FOPU/PET films have reached the level of oil wettability and surface energy significantly lower than that of polytetrafluoroethylene, a fully perfluorinated polymer. Specifically, the highest level of the repellency is observed with an oligomeric additive, which was made using aromatic diisocyanate as a comonomer and has CF3 end-group. This semicrystalline oligomer has a glass transition temperature (Tg) well above room temperature, and we associate the superiority of the material in achieving low water and oil wettability with its ability to effectively retain CF3 and CF2 moieties in contact with the test wetting liquids.

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Section: Wettability Of Fopusmentioning

confidence: 94%

Section: Synthesis and Characterization Of Fopusmentioning

confidence: 99%

Section: Water and Oil Repellency Of Hfopu-1 And Mfopu-1mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Towards a Long-Chain Perfluoroalkyl Replacement: Water and Oil Repellent Perfluoropolyether-Based Polyurethane Oligomers

et al. 2021

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“…where W is the PP mass fraction, ΔHm (J.g −1 ) is the melting enthalpy determined from the 1st and 2nd heating steps and ΔHm 100 corresponds to the estimated melting enthalpy of a fully crystalline PP (209 J g −1 ) [39,40]. functional groups specific to the polymer and biocomposites degradation.…”

Section: Spectrophotogoniometrymentioning

confidence: 99%

Exterior and under glass natural weathering of hemp fibers reinforced polypropylene biocomposites: Impact on mechanical, chemical, microstructural and visual aspect properties

Badji

Beigbeder

Garay

et al. 2018

Polymer Degradation and Stability

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This work aims to investigate exterior and under glass weathering representing decking and car interior end uses of hemp fibers reinforced polypropylene (PP) biocomposites. For this reason, mechanical flexural tests were firstly performed. Then, the evolution of the PP matrix microstructure was determined through Differential Scanning Calorimetry (DSC). The chemical composition was studied by infrared spectroscopy to understand the photo-and thermo-chemical mechanisms. CIELab system-based colorimetric measurements were carried out to determine the evolution of the chromaticity and lightness. Through a new approach, gloss was obtained by determining the type of reflection of materials as either specular or diffuse, and the surface aspect was characterized by rugosimetry. The influence of the rate of hemp fibers (from 0 to 30 wt%) was studied. Results showed that biocomposites were generally more sensitive than neat PP whatever the weathering conditions. However, each type of weathering assessment allowed understanding the contribution of each degradation factor. Indeed, rainfall or UV-A rays induced an increase in the vinyl concentration and the formation of cracks on the surface whereas the carbonyl functional groups rate was not influenced by the type of weathering. The high temperatures under windshield glass favored a chemicrystallization and biocomposites yellowing at the first period of exposition whereas outdoor exposure induced red color loss.

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Volumetric Printing of Thiol‐Ene Photo‐Cross‐Linkable Poly(ε‐caprolactone): A Tunable Material Platform Serving Biomedical Applications

et al. 2023

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Current thoroughly described biodegradable and cross‐linkable polymers mainly rely on acrylate cross‐linking. However, despite the swift cross‐linking kinetics of acrylates, the concomitant brittleness of the resulting materials limits their applicability. Here, photo‐cross‐linkable poly(ε‐caprolactone) networks through orthogonal thiol‐ene chemistry are introduced. The step‐growth polymerized networks are tunable, predictable by means of the rubber elasticity theory and it is shown that their mechanical properties are significantly improved over their acrylate cross‐linked counterparts. Tunability is introduced to the materials, by altering Mc (or the molar mass between cross‐links), and its effect on the thermal properties, mechanical strength and degradability of the materials is evaluated. Moreover, excellent volumetric printability is illustrated and the smallest features obtained via volumetric 3D‐printing to date are reported, for thiol‐ene systems. Finally, by means of in vitro and in vivo characterization of 3D‐printed constructs, it is illustrated that the volumetrically 3D‐printed materials are biocompatible. This combination of mechanical stability, tunability, biocompatibility, and rapid fabrication by volumetric 3D‐printing charts a new path toward bedside manufacturing of biodegradable patient‐specific implants.

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Crosslinked Polymers and Rubber Elasticity

Cited by 11 publications

References 66 publications

Towards a Long-Chain Perfluoroalkyl Replacement: Water and Oil Repellent Perfluoropolyether-Based Polyurethane Oligomers

Towards a Long-Chain Perfluoroalkyl Replacement: Water and Oil Repellent Perfluoropolyether-Based Polyurethane Oligomers

Exterior and under glass natural weathering of hemp fibers reinforced polypropylene biocomposites: Impact on mechanical, chemical, microstructural and visual aspect properties

Volumetric Printing of Thiol‐Ene Photo‐Cross‐Linkable Poly(ε‐caprolactone): A Tunable Material Platform Serving Biomedical Applications

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