Polymerization and Finishing Melt Processible Fluoropolymers

Ebnesajjad, Sina

doi:10.1016/b978-188420796-9.50008-4

Cited by 20 publications

(24 citation statements)

References 28 publications

(33 reference statements)

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“…Only the mechanical blended sample showed excessive mass loss at a preform pressure of 140 MPa due to excessive cracking of billets [Figure (b)]. It is known that unfilled PTFE does experience mass loss during processing due to slight degradation of PTFE at temperatures above its melting point . The higher mass loss shown with increasing graphene loading might be explained due to the increased thermal conductivity attributed by the graphene nanoplatelet shape and presence which also accelerate thermo‐oxidative decomposition of the PTFE.…”

Section: Resultsmentioning

confidence: 99%

Preparation of PTFE/graphene nanocomposites by compression moulding and free sintering: A guideline

Rooyen

Bissett

Khoathane

et al. 2016

J of Applied Polymer Sci

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Abstract:This work was aimed at preparing polytetrafluoroethylene (PTFE) nanocomposites filled with graphene nanoplatelets and investigating how the graphene nanoplatelets and the preparation techniques influenced the physical properties. Graphene was incorporated up to 4 vol% of the total PTFE system by dry and solvent assisted blending. The powder compaction was evaluated using the Kawakita/Ludde model to describe the compressibility of the powder blends. The nanocomposite billets were prepared using cold compression moulding by applying preform pressures between 12.7 and 140 MPa and the preform billets were sintered at 380 °C using a specific sintering cycle. The changes in the physical dimensions, billet mass, density, and void content of the billets, pre and post sintering, were analysed with Experimental design software to evaluate the influence of the pre-compaction pressure and graphene loading. From the evaluation it was concluded that the ideal compaction pressure was at 12.7 MPa and the solvent assisted blending was superior to the mechanical blending method. Furthermore, the compression creep tests confirmed the ideal processing temperature and graphene loading range to improve the mechanical properties.2

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Section: Resultsmentioning

confidence: 99%

Preparation of PTFE/graphene nanocomposites by compression moulding and free sintering: A guideline

Rooyen

Bissett

Khoathane

et al. 2016

J of Applied Polymer Sci

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“…Proces ten polega na wyt³aczaniu uplastycznionego wê¿a grubooeciennego i nastêpnym mechanicznym ograniczeniu rozci¹gania na drodze rozdmuchiwania jego odcinka zamkniêtego w formie wyt³aczarsko-rozdmuchowej (formie WR) [10][11][12][13]. W ten sposób otrzymuje siê przede wszystkim oerednich wymiarów pojemniki z tworzyw termoplastycznych do napojów, leków, oerodków chemicznych i kosmetyków [8,14] a tak¿e o wiêkszych rozmiarach, np.…”

Section: Charakterystyka Wyt£aczania Z Rozdmuchiwaniem Nieswobodnymunclassified

Processing and functional properties of the containers prepared by blowing extrusion in variable processing conditions, and evaluation of yield and quality of the process

Pepliński¹,

Bieliński²

2009

Polimery

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Streszczenie -Scharakteryzowano proces przetwórczy polegaj¹cy na wyt³aczaniu z rozdmuchiwaniem nieswobodnym (w formie). Metod¹ t¹ wytwarzano pojemniki z bimodalnego PE-HD stosuj¹c rozmaite warunki przetwórstwa, tj. zmienn¹ temperaturê (Tm) i grubooeae (gw) wê¿a wyt³aczanego tworzywa oraz cioenienie rozdmuchiwania (pb). Oceny w³aoeciwooeci u¿ytkowych uzyskanych wytworów a tak¿e jakooeci i wydajnooeci procesu dokonano na podstawie wyznaczonego skurczu przetwórczego pojemnika, jego w³aoeciwooeci mechanicznych jak równie¿ miary odwzorowania powierzchni oecianki gniazda formy (chropowatooeci). Jako wyznacznik tej oceny zaproponowano zestaw odpowiednich wskaŸników; ilooeciowe zale¿nooeci wybranych wskaŸników od ww. warunków przetwórstwa przedstawiono w postaci równañ. S³owa kluczowe: wyt³aczanie z rozdmuchiwaniem, warunki przetwórstwa, skurcz przetwórczy, parametr chropowatooeci, pojemniki, w³aoeciwooeci mechaniczne, wydajnooeae i jakooeae procesu, wskaŸniki oceny. Summary -The process of blowing extrusion has been characterized ( Fig. 1, 2, 4, 9). The containers made of bimodal PE-HD were prepared in this way at variable processing conditions i.e. variable temperature (Tm), polymer parison thickness (gw) and different blowing pressure (pb). Functional properties of the products obtained as well as the quality and yield of the process were evaluated on the basis of processing shrinkage (Fig. 3, 8), mechanical properties of the products (Fig. 5) and on the measure of mapping of mold cavity wall surface (surface roughness) ( Fig. 6, 7). The set of the proper indices has been proposed as a measure of this evaluation. Qualitative dependence of selected indices on the processing conditions is given in equations (Table 1). **) Artyku³ zawiera treoeae wyst¹pienia prezentowanego na XIII Profesorskich Warsztatach Naukowych "Przetwórstwo Tworzyw Polimerowych", Lublin, 8-11 czerwca 2008 r.

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“…In addition, because of its good mechanical and thermal stability, PTFE has been extensively applied as wire insulation material. The main physical and chemical properties of PTFE are compared with those of polyethylene (PE) in Table 1 [6].…”

Section: Sample Materialsmentioning

confidence: 99%

Dielectric Properties of PTFE Wiring Insulation as a Function of Thermal Exposure

Bowler

Yoon

et al. 2008

2008 Annual Report Conference on Electrical Insulation and Dielectric Phenomena

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The study of polymers used in electrical insulation of wiring is important to the aerospace industry due to potential loss of life and aircraft in the event of an electrical fire caused by breakdown of wiring insulation. In this work, the effect of thermal exposure on the permittivity of PTFE is studied in order to examine the feasibility of developing of a capacitive nondestructive testing method to indicate the presence of a significant defect in the wiring insulation, following thermal exposure, by measuring its permittivity. Measurements of permittivity, obtained using a Novocontrol dielectric spectrometer with a temperature-controlled sample cell, reveal a significant reduction in permittivity as a function of duration of heat exposure at 360 'C. The capacity of PTFE samples was also measured over the frequency range 1 Hz to 1 MHz at various temperatures from -150 to 300°C.

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Polymerization and Finishing Melt Processible Fluoropolymers

Cited by 20 publications

References 28 publications

Preparation of PTFE/graphene nanocomposites by compression moulding and free sintering: A guideline

Preparation of PTFE/graphene nanocomposites by compression moulding and free sintering: A guideline

Processing and functional properties of the containers prepared by blowing extrusion in variable processing conditions, and evaluation of yield and quality of the process

Dielectric Properties of PTFE Wiring Insulation as a Function of Thermal Exposure

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