Surfactant effects in polytetrafluoroethylene dispersion polymerization

Thermal properties at room temperature of polytetrafluoroethylene

“…Our interpretation is in a good agreement with both the morphologies described by Luhman [11] and Rahl [12]. In fact, both low-molecular weight chain and defect-rich crystals would give lower transition temperatures than high-molecular weight chain and defectless crystals, respectively [1,6].…”

“…In fact, both low-molecular weight chain and defect-rich crystals would give lower transition temperatures than high-molecular weight chain and defectless crystals, respectively [1,6]. Luhman et al [11] described native PTFE as constituted of three types of particles with different morphology: rod-like, roughly spherical and in the ease of very low molecular weight, small hexagons. The small hexagonal single crystals are considered to be responsible for the first transition peak and could correspond to our low-transient crystalline component.…”

“…Recently Luhman et al [11], through electron microscopy, have observed, in native PTFE, three types of particles with different morphology: rod-like, roughly spherical and, in case of very low molecular weight, small hexagonal particles. The rod-like particles and the hexagons are single crystals, while the spherical particles are aggregated of a number of crystals.…”

Phase behavior at low temperature of poly(tetrafluoroethylene) by temperature-modulated calorimetry

“…We interpreted it as the triclinic-hexagonal transition of morphologically disordered PTFE crystals. This interpretation is in agreement with microscopic observations of native PTFE [13,14]. In Fig.…”

“…An electron microscopy study by Luhmann and Feiring revealed rod-like, roughly spherical and, in the case of very low molecular weight material, small hexagonal particles [14]. The rod-like and the hexagonal particles were single crystals, while the spherical particles were aggregates.…”