Fluoroalkylsilanes in silica/fluoropolymer composites

Fields, Jeffrey T.; Garton, A.; Poliks, Mark D.

doi:10.1002/pc.10609

Cited by 13 publications

(9 citation statements)

References 11 publications

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“…The interface in filled PTFE materials cannot be very strong due to the high self-constraint -CF 2 -unit in the PTFE molecule, which results in low surface energy of the PTFE matrix. Glass fiber has the same surface structure as particulate silica [35], although the interface of glass fiber/PTFE can be readily adjusted due to the existence of fluoroalkylsilanes (FSI) [36] and/or silane [37]. Thus, the interfaces in filled PTFE materials may be classified as a weak interface.…”

Section: Fatigue Behavior Of Particle Filled Polymeric Materialsmentioning

confidence: 99%

Fatigue Fracture Mechanisms of Particle and Fiber Filled PTFE Composites

Gan

Aglan

Faughnan

et al. 2001

Journal of Reinforced Plastics and Composites

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The effect of filler type on the fatigue fracture mechanisms of polytetrafluoroethylene (PTFE) composites was studied. The two composites were a silica particle filled PTFE (Garlock 3502‘) and a glass fiber filled PTFE (Garlock 8573‘). Tension-tension fatigue crack propagation tests were conducted on both materials at room temperature at a frequency of 3 Hz. The maximum stress was 6 MPa and the ratio of minimum load to maximum load was 0.1. It was found that the fatigue lifetime of the particle filled PTFE is approximately four times higher than that of the fiber filled PTFE. The fatigue data also revealed that the crack speed of the particle filled composite is always lower than that of the short fiber filled composite. Microscopic analysis on representative fracture surface of each material was performed to identify different fracture surface features. The three fracture regions, crack initiation, stable crack growth and unstable crack growth were examined. In the first region, both composites displayed extensive plastic deformation and severe debonding at the filler/matrix interface. In the second region, stable crack propagation, torn ligament bundles, fibrillation and debonded fillers are the main fracture surface features. The fracture surface of the fiber filled PTFE in the unstable crack propagation region has a more smooth appearance with extensive fiber pull-out. This indicates a fast fracture process and a brittle fracture mechanism dominating this region. The third region of the fracture surface for the particle filled PTFE displayed more severe matrix deformation. The particle filled PTFE displayed more intensive fibrillation in the second region than the fiber filled PTFE, indicating more damage formation and thus higher energy consumption in the stable crack propagation stage. Consequently, the crack speed of the particle filled PTFE is lower than that of the fiber filled PTFE composite.

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Section: Fatigue Behavior Of Particle Filled Polymeric Materialsmentioning

confidence: 99%

Fatigue Fracture Mechanisms of Particle and Fiber Filled PTFE Composites

Gan

Aglan

Faughnan

et al. 2001

Journal of Reinforced Plastics and Composites

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“…Typically, such improvements are attributed to the combination of a reduction in void content and an effective decrease of the hydrophilicity of the filler surface, which is provided by the coupling agent. 7 In other cases, the primary benefit appears to be an improvement in the dispersion of filler in the composite, possibly by reducing the local viscosity and facilitating the breakup of agglomerates. [7][8][9][10] Research on polymer nanocomposites has exploded over the last decade, and a few recent review articles can be found.…”

Section: Introductionmentioning

confidence: 99%

“…7 In other cases, the primary benefit appears to be an improvement in the dispersion of filler in the composite, possibly by reducing the local viscosity and facilitating the breakup of agglomerates. [7][8][9][10] Research on polymer nanocomposites has exploded over the last decade, and a few recent review articles can be found. 11,12 Composites with features on the scale of nanometers often exhibit properties superior to their macroscale counterparts, such as strength, stiffness, barrier, and thermal and oxidative properties.…”

Section: Introductionmentioning

confidence: 99%

“…It has been reported1, 6 that the use of a conventional coupling agent (silane) offers a higher level of performance, including improved compliance, flexural endurance, ductility, peel strength, and lower water absorption. Typically, such improvements are attributed to the combination of a reduction in void content and an effective decrease of the hydrophilicity of the filler surface, which is provided by the coupling agent 7. In other cases, the primary benefit appears to be an improvement in the dispersion of filler in the composite, possibly by reducing the local viscosity and facilitating the breakup of agglomerates 7–10…”

Section: Introductionmentioning

confidence: 99%

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Preparation and properties of silylated PTFE/SiO₂ organic–inorganic hybrids via sol–gel process

Chen

Tsai

Lee

2004

J. Polym. Sci. A Polym. Chem.

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A study on poly(tetrafluoroethylene) (PTFE) reinforced with tetraethoxysilanes (TEOS) derived SiO 2 is described. It included the manufacturing process of SiO 2 -reinforced PTFE and the effects of silylation agent on the properties of the hybrid material, such as porosity, hydrophobic, thermal resistance, dielectric and mechanical properties, and microstructure. PTFE/SiO 2 hybrids of 50 wt % SiO 2 loading were prepared via a sol-gel process and were shaped by a two-roll milling machine. Trimethylchlorosilane and hexamethydisilazane were used as the silylation agents. Our results showed that the water absorption and dielectric loss of PTFE/SiO 2 hybrid had significantly improved with silylation agent. The silylation process replaced SiOOH with SiOCH 3 on the surface of the TEOS-derived silica colloidal particle. The existence of trimethylsilyl [OSi(CH 3 ) 3 ] on the surface of the modified PTFE/SiO 2 hybrid was confirmed via infrared and solid-state 29 Si magic-angle spinning nuclear magnetic resonance spectra. Nitrogen-sorption techniques were used to characterize the modified and unmodified PTFE/SiO 2 hybrids. The microstructure of SiO 2 in the matrix was also evaluated with scanning electron microscopy and transmission electron microscopy. Our results showed that the silylated sol-gel-derived PTFE/SiO 2 hybrids had exhibited high porosity (53.7%) with nanosize pores (10 -40 nm) and nanosize colloidal particles (20 -50 nm). This manifests itself as have the ultralow dielectric properties (D k ϭ 1.9 and D f ϭ 0.0021), low coefficient of thermal expansion (66.5 ppm/°C), high tensile modulus (141 MPa), excellent thermal resistance (T d ϭ 612°C), and an increased hydrophobia ( ϭ 114°); moreover, the hydrophobic property of the PTFE/SiO 2 hybrid was thermally stable up to 400°C.

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“…Still a basic requirement for fluoropolymer nse is the need to ensure minimal thermal mismatch in an electronic package and this is met by incorporating fillers into these films. Typically, these fillers contain coupling agents that serve as aids to provide bonding between the filler particles and the polymer matrix [4]. Metallization of fluoropolymer-based composite films for PCB fabrication can be accomplished by electroplating or by laminating the polymer composites surfaces to copper foils.…”

Section: Introductionmentioning

confidence: 99%

Interfacial adhesion of fluoropolymer composites to commercial copper foils subjected to aqueous photolithographic processes

Matienzo

Jimarez

1995 Proceedings. 45th Electronic Components and Technology Conference

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Three commercial copper foils containing various degrees of surface roughness and a chemically similar surface treatment were laminated to a fluoropolymer composite and also subjected to water-based photolithographic and stripping processes. Surface analysis performed on the processed foils indicated that the highly basic pH of the stripping process was effective in removing zinc oxide, a component of the surface treatments on these foils. Morphologically, however, the surfaces did not seem to change. Ninety degree peel measurements of the resulting interfaces with aud without a photoresist processes showed that the resulting practical adhesion seemed to be mainly controlled by mechanical interlocking and to a lesser amount, by chemical factors. When 50 pm wide lines were subjected to the photolithographic process and a full fabrication sequence, adhesion variability seemed to be affected by interfacial attack of the fluoropolymer/metal foil interface by the alkaline medium of stripping and other process chemicals. Reliable interfacial adhesion of narrow lines is only possible when process parameters have been optimized.

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Fluoroalkylsilanes in silica/fluoropolymer composites

Cited by 13 publications

References 11 publications

Fatigue Fracture Mechanisms of Particle and Fiber Filled PTFE Composites

Fatigue Fracture Mechanisms of Particle and Fiber Filled PTFE Composites

Preparation and properties of silylated PTFE/SiO₂ organic–inorganic hybrids via sol–gel process

Interfacial adhesion of fluoropolymer composites to commercial copper foils subjected to aqueous photolithographic processes

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Fluoroalkylsilanes in silica/fluoropolymer composites

Cited by 13 publications

References 11 publications

Fatigue Fracture Mechanisms of Particle and Fiber Filled PTFE Composites

Fatigue Fracture Mechanisms of Particle and Fiber Filled PTFE Composites

Preparation and properties of silylated PTFE/SiO2 organic–inorganic hybrids via sol–gel process

Interfacial adhesion of fluoropolymer composites to commercial copper foils subjected to aqueous photolithographic processes

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Preparation and properties of silylated PTFE/SiO₂ organic–inorganic hybrids via sol–gel process