Endgroups in tetrafluoroethylene polymers

Bro, M. I.; Sperati, Carleton A.

doi:10.1002/pol.1959.1203813401

Cited by 66 publications

(27 citation statements)

References 9 publications

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“…[1] Bisulfite initiators form sulfonic acid end groups as identified by polymerization of TFE using an iron-bisulfite initiator containing radioactive sulfur 35 S. [2] The importance of this study [2] is that it has provided quantitative evidence of PTFE molecular weight. The key point is that there is no sulfur in the polymer when persulfate is the initiator as demonstrated by Bro and Sperati.…”

Section: Homopolymerizationmentioning

confidence: 99%

Polymerization and Finishing Melt Processible Fluoropolymers

Ebnesajjad¹

2003

Melt Processible Fluoroplastics

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Section: Homopolymerizationmentioning

confidence: 99%

Polymerization and Finishing Melt Processible Fluoropolymers

Ebnesajjad¹

2003

Melt Processible Fluoroplastics

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“…Such migration will lead to environmental problems as they are nonbiodegradable and bioaccumulate in human fatty tissues. 5 Additionally, the ionic initiator will also result in the incorporation of thermally unstable carboxylic acid and acid fluoride end-groups 6 which are deleterious to the products during processing and application. Those unstable end-groups would inevitably release certain toxic compounds, such as perfluoroisobutene and hydrofluoride, 7 which are highly harmful to the human body.…”

Section: Introductionmentioning

confidence: 99%

Copolymerizations of tetrafluoroethylene and perfluoropropylvinyl ether in supercritical carbon dioxide: Polymer synthesis, characterization, and thermal properties

Yuan

Zhao

et al. 2011

J of Applied Polymer Sci

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Tetrafluoroethylene (TFE) and perfluoropropylvinyl ether (PPVE) were copolymerized in supercritical carbon dioxide (sc-CO 2 ) with a perfluorodiacyl initiator bis(perfluoro-2-n-propoxypropionyl) peroxide (BPPP). The resultant copolymers with stable perfluoroalkyl end groups were obtained, avoiding the decomposition during processing and applications. Reactivity ratios of TFE and PPVE were first reported. The r TFE and r PPVE values are about 8 and 0.08, respectively. Such parameters are significant for the modification of PTFE through copolymerization of TFE and PPVE. It is found that through increasing the reaction pressure from 8.5 to 25 MPa, while r TFE increases by 12.0%, r PPVE decreases by 9.0%, which should be ascribed to the enhancement of the polarity of CO 2 under high pressures.Because the reactivity of TFE is by two orders of magnitude higher than that of PPVE; on one hand, the copolymerization rate falls rapidly with the decrease of TFE feed ratio; on the other hand, TFE content in the copolymer decreases with the reaction time. All copolymers containing different fractions of PPVE enjoy outstanding thermal stability. The DSC result indicates that there exist two forms of crystals with highly regular molecular arrangement or less ordered chain packing which is disturbed by perfluoropropyl pendants.

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“…Study of the IR laser radiation effect, in particular, gas discharge CO and CO 2 lasers in the 5-11 μm wavelength range, is of great interest owing to the fact that FP partly absorbs IR radiation in this range, and its absorptivity differs at different wavelengths [1,2], which allows one to control the degree of heating of the material during laser irradi ation and initiate the phase transformation from the crystalline to amorphous state when sintering at specific laser fluences [3].…”

Section: Introductionmentioning

confidence: 99%