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In presence of even a small amount of oxygen, singlet oxygen is formed during operation, by energy transfer from the excited polymer molecules to oxygen molecules. These oxygen radicals then attack the structure of the polymer, leading to its degradation. [citation needed] PPV has also been investigated as an electron-donor in organic solar ...
Compared to other fluoropolymers, it has an easier melt process because of its relatively low melting point of around 177 °C. Processed materials are typically in the non-piezoelectric alpha phase. The material must either be stretched or annealed to obtain the piezoelectric beta phase.
Proton-exchange membrane fuel cells (PEMFC), also known as polymer electrolyte membrane (PEM) fuel cells, are a type of fuel cell being developed mainly for transport applications, as well as for stationary fuel-cell applications and portable fuel-cell applications. Their distinguishing features include lower temperature/pressure ranges (50 to ...
The majority of linkages in PVF are head-to-tail, and only 12-18 % of linkages are head-to-head. These irregularities are probably the cause of the variations in melting point, which ranges from 185 °C to 210 °C. The crystallinity of PVF ranges from 20 to 60%, depending on the polymerization method and thermal history of the polymer.
PTFE has a higher melting point and is more crystalline than PCTFE, but the latter is stronger and stiffer. Though PCTFE has excellent chemical resistance, it is still less than that of PTFE. [22] PCTFE has lower viscosity, higher tensile strength and creep resistance than PTFE. [1] PCTFE is injection-moldable and extrudable, whereas PTFE is ...
Higher lifetime of methanol fueled HT-PEM fuel cell system than for DMFC system is possible. Pure fuels or water-fuel mixtures are applicable (depending on fuel cell system design). Use of renewable fuels is possible. Cold storage temperatures below 0 °C are no problem for the fuel cell membrane in contrast to DMFC and LT-PEM fuel cell.
Polyvinyl alcohol (PVOH, PVA, or PVAl) is a water-soluble synthetic polymer. It has the idealized formula [CH 2 CH(OH)] n. It is used in papermaking, textile warp sizing, as a thickener and emulsion stabilizer in polyvinyl acetate (PVAc) adhesive formulations, in a variety of coatings, and 3D printing. It is colourless (white) and odorless.
A Assuming an altitude of 194 metres above mean sea level (the worldwide median altitude of human habitation), an indoor temperature of 23 °C, a dewpoint of 9 °C (40.85% relative humidity), and 760 mmHg sea level–corrected barometric pressure (molar water vapor content = 1.16%). B Calculated values *Derived data by calculation.