Redox cationic polymerization: The diaryliodonium salt/ascorbate redox couple

Crivello, James V.; Lam, J. H. W.

doi:10.1002/pol.1981.170190227

Cited by 54 publications

(31 citation statements)

References 13 publications

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“…Indeed, much of the reaction chemistry of both these classes of compounds involves their reduction. Work in this laboratory has shown that diaryliodonium salts can be employed together with reducing agents such as ascorbates [9], benzoins [10] , or tin(II) compounds [11] to initiate cationic polymerizations at room temperature , . Similarly, oxidizable free radicals generated either by thermolytic or by photolytic methods can be used as reducing agents for diaryliodonium salts.…”

Section: I Imentioning

confidence: 99%

Redox Initiated Cationic Polymerization: Reduction of Triarylsulfonium Salts by Silanes

Crivello

2009

Silicon

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A novel redox initiator system for carrying out the cationic polymerization of epoxide, oxetane and vinyl ether monomers has been developed. The redox couple is based on a triarylsulfonium salt as the oxidant with an organosilane as the reducing agent. The reaction between these two agents is markedly catalyzed by platinum and palladium complexes. Cationic polymerizations using this redox initiator system were carried out in a conventional manner with neat monomer or under solution conditions. This paper also describes the novel use of a two-component redox system in which the silane is delivered to the monomer sample in the vapor state. Optical pyrometry (infrared thermography) was employed as a convenient method with which to monitor the polymerizations. A study of the effects of variations in the structures of the triarylsulfonium salt, the silane and the type of noble metal catalyst were carried out. The use of this initiator system for carrying out commercially attractive cross-linking polymerizations for coatings, composites and electronic encapsulations is discussed.

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Section: I Imentioning

confidence: 99%

Redox Initiated Cationic Polymerization: Reduction of Triarylsulfonium Salts by Silanes

Crivello

2009

Silicon

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“…It is known that the DPI·BF 4 /BPO initiator system makes the reaction to form a free radical-cationic dual reaction system, in which the free radical produced from BPO can accelerate cationic ring-opening reaction and plays a coordination role for cationic reaction, because it plays an indirect role in the electron transfer of the iodonium salt [13][14][15]. The free radical is produced through the thermal decomposition of BPO at about 80 °C , which could act as the reducing agent of onium salts, and induce DPI·BF 4 to generate cationic active state.…”

Section: The Effect Of Bpo Content On Thermal Polymerizationmentioning

confidence: 99%

“…But the report for the thermal cationic polymerization initiated with phenyliodonium salt is fewer than others. The thermal cationic polymerizations of cyclohexene oxide, tetrahydrofuran, and s-trioxane using the diaryliodonium salt/ascorbate redox couple as initiator were studied by Crivello et al [15]. We have already studied the hybrid free radical-cationic thermal polymerization of methylacryloylpropyl-POSS/epoxy resin nanocomposites [16].…”

Section: Introductionmentioning

confidence: 97%

Hybrid cationic ring-opening polymerization of epoxy resin/glycidyloxypropyl-polyhedral oligomeric silsesquioxane nanocomposites and dynamic mechanical properties

Hou

Han

et al. 2015

Iran Polym J

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“…Crivello et al found that the diaryl iodonium PAG is reduced during the decomposition reaction, and the products can lower the energy required for the deprotection reaction. 16 It is likely that TMPEO acts as a reducing agent in this system, and the decomposition temperature of the PAG depends on the concentration of TMPEO. The QCM and TGA results correlate well for formulations with 3 pphr PAG and 10 pphr TMPEO.…”

Section: Methodsmentioning

confidence: 99%

Improved Mechanical Properties of Chemically Amplified, Positive Tone, Polynorbornene Dielectric

Mueller

Schwartz

Sutlief

et al. 2014

ECS J. Solid State Sci. Technol.

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The mechanical properties of an aqueous developed, chemically amplified, polynorbornene-based permanent dielectric have been investigated. The previously reported hexafluoroisopropanol norbornene and tert-butyl ester norbornene copolymer has been modified via two routes to improve the mechanical properties of the polymer and enable thick-film deposition. First, a third monomer, butyl norbornene (ButylNB) was added to the polymer backbone. The inclusion of 24 mol% ButylNB lowered the elastic modulus from 2.64 to 2.35 GPa and raised the dielectric constant from 2.78 to 3.48. The second approach added a low molecular weight, plasticizing additive in the copolymer formulation. Many additives were immiscible with the resin or did not affect the mechanical properties. Trimethyololpropane ethoxylate (TMPEO) was found to be a miscible additive that improved mechanical properties and could participate in crosslinking the final dielectric material. TMPEO interacted with the PAG, lowering its decomposition temperature. An optimal formulation and processing scheme were determined. A formulation with 10 pphr TMPEO was measured to have a dielectric constant of 2.94, an elastic modulus of 1.95 GPa, a sensitivity at 365 nm of 175 mJ/cm 2 , and a contrast of 4. Photo-definable, permanent, low-k dielectrics are widely used in the fabrication of microelectronic devices and packages.1-5 These dielectrics electrically isolate the interconnect and mechanically stabilize the structures for the life of the device. On integrated circuits, organic dielectrics can be used for interlayer isolation and/or the stress buffer layer on top of the device. Stress buffer layers protect the top surface of the chip and can mitigate mechanical failures that arise from a mismatch of the coefficient of thermal expansion between the chip and package during thermal cycling. In microelectronics packages, low-k dielectrics can be used in the buildup layers, electrically separating the electrical conductors. Low permittivity is critical for use in these applications, as it affects device performance, energy loss, and signal integrity.Photo-definability is an attractive property for permanent polymeric dielectrics. The ability to directly pattern the dielectric by photolithographic techniques mitigates the need for a separate photoresist and pattern transfer steps. This can lower the overall fabrication cost and reduce the number of individual process steps.2 For stress buffer and redistribution applications, positive tone photo-definable dielectrics are more desirable than negative tone ones because the lithographic mask is mostly opaque mask and less prone to transfer particle defects. Also, holes and lines in positive tone materials exhibit sloped sidewalls (opening wider at the top) which is beneficial for void-free plating of the copper interconnects. Aqueous developability is another attractive property, as it mitigates the need for environmentally harmful organic solvent developers. Further, the dielectric should exhibit high sensitivity and contrast ...

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Redox cationic polymerization: The diaryliodonium salt/ascorbate redox couple

Cited by 54 publications

References 13 publications

Redox Initiated Cationic Polymerization: Reduction of Triarylsulfonium Salts by Silanes

Redox Initiated Cationic Polymerization: Reduction of Triarylsulfonium Salts by Silanes

Hybrid cationic ring-opening polymerization of epoxy resin/glycidyloxypropyl-polyhedral oligomeric silsesquioxane nanocomposites and dynamic mechanical properties

Improved Mechanical Properties of Chemically Amplified, Positive Tone, Polynorbornene Dielectric

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