Chemical Resistance and Mechanical Stability of Polymer Film Heat Exchangers

Laaber, Dmitrij; Bart, Hans‐Jörg

doi:10.1002/cite.201400045

Cited by 10 publications

(5 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Polymeric materials have been widely used in industry because of their low cost and excellent properties, including high strength-to-weight ratio, chemical stability, and corrosion resistance. − High thermal conductivity ( k ) can significantly improve polymers’ capability of heat dissipation, tolerance to thermal impulse, and so on. Highly thermal conductive polymers are very sought after for applications in thermal design of flexible electronics as the substrate for excellent heat dissipation, apparel of reduced heat stress to quickly respread the accumulated heat from sensitive body areas, and to conduct the heat to the environment, and as fillers to make high-performance material interfaces used in central processing unit cooling.…”

Section: Introductionmentioning

confidence: 99%

Novel Polyethylene Fibers of Very High Thermal Conductivity Enabled by Amorphous Restructuring

et al. 2017

View full text Add to dashboard Cite

High-thermal-conductivity polymers are very sought after for applications in various thermal management systems. Although improving crystallinity is a common way for increasing the thermal conductivity ( k ) of polymers, it has very limited capacity when the crystallinity is already high. In this work, by heat-stretching a highly crystalline microfiber, a significant k enhancement is observed. More interestingly, it coincides with a reduction in crystallinity. The sample is a Spectra S-900 ultrahigh-molecular-weight polyethylene (UHMW-PE) microfiber of 92% crystallinity and high degree of orientation. The optimum stretching condition is 131.5 °C, with a strain rate of 0.0129 s –1 to a low strain ratio (∼6.6) followed by air quenching. The k enhancement is from 21 to 51 W/(m·K), the highest value for UHMW-PE microfibers reported to date. X-ray diffraction study finds that the crystallinity reduces to 83% after stretching, whereas the crystallite size and crystallite orientation are not changed. Cryogenic thermal characterization shows a reduced level of phonon-defect scattering near 30 K. Polarization Raman spectroscopy finds enhanced alignment of amorphous chains, which could be the main reason for the k enhancement. A possible relocation of amorphous phase is also discussed and indirectly supported by a bending test.

show abstract

Section: Introductionmentioning

confidence: 99%

Novel Polyethylene Fibers of Very High Thermal Conductivity Enabled by Amorphous Restructuring

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Typical polymers are well-documented to have a low thermal conductivity ( k ) in the order of 0.1 W/(m·K) . Polymers with a high k have been promising candidates for industrial applications combining with their other characteristics such as mechanical flexibility, high corrosion resistance, lighter weight, and chemical stability. − Examples of applications include solar hot-water collectors, heat exchangers, electronic packaging, membranes, microelectronic devices and nanocomposites, − gas sensors, field-effect transistors, and other fields . Even though bulk polymers have a low k , the polymers can be manipulated and improved via structure engineering and tailoring to achieve relatively high k .…”

Section: Introductionmentioning

confidence: 99%

Thermal Conductivity of Ultrahigh Molecular Weight Polyethylene Crystal: Defect Effect Uncovered by 0 K Limit Phonon Diffusion

Liu

Cheng

et al. 2015

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

Crystalline ultrahigh molecular weight polyethylene (UHMWPE) has the highest reported thermal conductivity at room temperature: 104 W/(m·K), while theoretical predictions proposed an even higher value of 300 W/(m·K). Defects and amorphous fraction in practical UHMWPE fibers significantly reduces the thermal conductivity from the ideal value. Although the amorphous effect can be readily analyzed based on the effective medium theory, the defect effects are poorly understood. This work reports on the temperature-dependent behavior (down to 22 K) of thermal diffusivity and conductivity of UHMWPE fibers in anticipation of observing the reduction in phonon density and scattering rate against temperature and of freezing out high-momentum phonons to clearly observe the defect effects. By studying the temperature-dependent behavior of thermal reffusivity (Θ, inverse of thermal diffusivity) of UHMWPE fibers, we are able to quantify the defect effects on thermal conductivity. After taking out the amorphous region's effect, the residual thermal reffusivities (Θ0) for the studied two samples at the 0 K limit are determined as 3.45 × 10(4) and 2.95 × 10(4) s/m(2), respectively. For rare-/no-defects crystalline materials, Θ0 should be close to zero at the 0 K limit. The defect-induced low-momentum phonon mean free paths are determined as 8.06 and 9.42 nm for the two samples. They are smaller than the crystallite size in the (002) direction (19.7 nm) determined by X-ray diffraction. This strongly demonstrates the diffuse phonon scattering at the grain boundaries. The grain boundary thermal conductance (G) can be evaluated as G ≈ βρc(p)v with sound accuracy. At room temperature, G is around 3.73 GW/(m(2)·K) for S2, comparable to that of interfaces with tight atomic bonding.

show abstract

“…Additionally, polymers typically have a certain degree of gas permeability and a low thermal conductivity. 3D‐printing of polymeric materials as reactors is already established in special fields of reaction engineering [7] and also in the application of polymers for process equipment [8]. The combination of ISRU and 3D‐printing was already discussed as early as 2012 [9].…”

Section: Introductionmentioning

confidence: 99%

Polymeric Reactors for Catalytic Reactions beyond Earth

Friedland,

Güttel

2024

Chemie Ingenieur Technik

View full text Add to dashboard Cite

Current space missions to Luna and Mars are considering to use the resources, which can be found on‐site at the destination. This strategy named in‐situ resource utilization (ISRU) saves valuable pay‐load capacities during the rocket launch from the earth surface. Specifically, in mars missions it is intended to produce the necessary rocket fuel CH4 for the back‐transit to earth via water electrolysis and subsequent CO2 methanation. The present study elaborates this concept and examines the question if polymeric reactors are feasible for heterogeneously catalyzed reactions in applications beyond earth. The study aims at providing a theoretical backbone for a proof‐of‐concept. The evaluation is conducted theoretically by design considerations and adds experimental results to show the general feasibility of polymeric reactors for applicable reaction conditions.

show abstract

Chemical Resistance and Mechanical Stability of Polymer Film Heat Exchangers

Cited by 10 publications

References 15 publications

Novel Polyethylene Fibers of Very High Thermal Conductivity Enabled by Amorphous Restructuring

Novel Polyethylene Fibers of Very High Thermal Conductivity Enabled by Amorphous Restructuring

Thermal Conductivity of Ultrahigh Molecular Weight Polyethylene Crystal: Defect Effect Uncovered by 0 K Limit Phonon Diffusion

Polymeric Reactors for Catalytic Reactions beyond Earth

Contact Info

Product

Resources

About