Physical properties of polymers

Sippel, A.

doi:10.1007/bf01840027

Cited by 7 publications

(5 citation statements)

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“…High-molar-mass bottlebrush polymers are needed to achieve materials with good elastic properties . The exo -M polymerized faster and gave higher-molar-mass polymers than its counterpart since the ROMP favors exo - over the endo -macromonomer (2 h for exo -P vs 12 h for mix -P ) (Table ).…”

Section: Resultsmentioning

confidence: 99%

“…Infrared spectroscopy (IR) characterization showed the signals from the key functional groups; however, quantitative correlations between the peaks were not obvious (Figure S8). In solution, the bottlebrush polymer is more stretched and the number of entanglements is reduced. , Although bottlebrush polymers have a lower tendency to give chain entanglements, the effect cannot be overlooked for materials prepared from exo -P polymers that have higher molar masses.…”

Section: Resultsmentioning

confidence: 99%

“…33,34 High-molar-mass bottlebrush polymers are needed to achieve materials with good elastic properties. 35 The exo-M polymerized faster and gave higher-molar-mass polymers than its counterpart since the ROMP favors exo-over the endomacromonomer (2 h for exo-P vs 12 h for mix-P) (Table 1). 36 Although macromonomer mix-M was less reactive and needed longer polymerization time, it was nevertheless further used because the starting exo-/endo-5-norbornene-2-carboxylic acid is cheaper than the exo-5-norbornene carboxylic acid.…”

Section: Resultsmentioning

confidence: 99%

“…In solution, the bottlebrush polymer is more stretched and the number of entanglements is reduced. 35,39 Although bottlebrush polymers have a lower tendency to give chain entanglements, 33 the effect cannot be overlooked for materials prepared from exo-P polymers that have higher molar masses.…”

Section: Acs Applied Materialsmentioning

confidence: 99%

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On-Demand Cross-Linkable Bottlebrush Polymers for Voltage-Driven Artificial Muscles

Adeli

Owusu

Nüesch

et al. 2023

ACS Appl. Mater. Interfaces

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Dielectric elastomer actuators (DEAs) generate motion resembling natural muscles in reliability, adaptability, elongation, and frequency of operation. They are highly attractive in implantable soft robots or artificial organs. However, many applications of such devices are hindered by the high driving voltage required for operation, which exceeds the safety threshold for the human body. Although the driving voltage can be reduced by decreasing the thickness and the elastic modulus, soft materials are prone to electromechanical instability (EMI), which causes dielectric breakdown. The elastomers made by cross-linking bottlebrush polymers are promising for achieving DEAs that suppress EMI. In previous work, they were chemically cross-linked using an in situ free-radical UV-induced polymerization, which is oxygen-sensitive and does not allow the formation of thin films. Therefore, the respective actuators were operated at voltages above 4000 V. Herein, macromonomers that can be polymerized by ring-opening metathesis polymerization and subsequently cross-linked via a UV-induced thiol−ene click reaction are developed. They allow us to fast cross-link defect-free thin films with a thickness below 100 μm. The dielectric films give up to 12% lateral actuation at 1000 V and survive more than 10,000 cycles at frequencies up to 10 Hz. The easy and efficient preparation approach of the defect-free thin films under air provides easy accessibility to bottlebrush polymeric materials for future research. Additionally, the desired properties, actuation under low voltage, and long lifetime revealed the potential of the developed materials in soft robotic implantable devices. Furthermore, the C−C double bonds in the polymer backbone allow for chemical modification with polar groups and increase the materials' dielectric permittivity to a value of 5.5, which is the highest value of dielectric permittivity for a cross-linked bottlebrush polymer

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Acs Applied Materialsmentioning

confidence: 99%

See 2 more Smart Citations

On-Demand Cross-Linkable Bottlebrush Polymers for Voltage-Driven Artificial Muscles

Adeli

Owusu

Nüesch

et al. 2023

ACS Appl. Mater. Interfaces

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“…The next step in thermo-oxidative degradation of LDPE SBC 818 and LDPE SEB 853 has much higher activation energies, above 250 kJ/mol. The activation energies for breaking the bond between carbon and carbon can achieve such high values because the bond dissociation energies for C-C is 248-368 kJ/mol, 615 kJ/mol for C=C, and 812 kJ/mol for C≡C [24]. At this step, the breakage of the polymer chain occurs.…”

Section: Formation Of Radicals During Pe Thermo-oxidative Degradationmentioning

confidence: 99%

Thermal stability and degradation kinetics of bio-based low-density polyethylenes

Aniśko,

Sałasińska,

Barczewski

2023

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The analysis of degradation kinetics and thermogravimetric data provides insights into the thermal decomposition of bio-based polyethylene in different environments. To obtain those data the three grades of bio-based low-density polyethylene was selected and procced to the thermogravimetric analysis also with an additional analysis of evolved gases during thermal decomposition in air. This analysis enhances our understanding of these processes compared to the well-known thermal decomposition of petrochemical polyethylene.

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