Thermally initiated cationic polymerization and properties of epoxy siloxane

Morita, Yasumasa; Tajima, Seitarou; Suzuki, Hiroshi; Sugino, Hiroaki

doi:10.1002/app.22603

Cited by 43 publications

(37 citation statements)

References 13 publications

(13 reference statements)

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“…Another advantage of Pt‐DPTZ SSCs over commercial catalysts is their tolerance towards the epoxy group in substrates. Hydrosilylation with epoxy‐containing substrates is particularly important in Si‐polymer industry because the epoxy group provides desirable physiochemical properties to products . Unfortunately, Karstedt catalyst has been known to show low selectivity in these reactions, as it catalyzes undesired ring‐opening side reactions .…”

Section: Resultsmentioning

confidence: 93%

Alkene Hydrosilylation on Oxide‐Supported Pt‐Ligand Single‐Site Catalysts

et al. 2019

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Heterogeneous single‐site catalysts (SSCs), widely regarded as promising next‐generation catalysts, blend the easy recovery of traditional heterogeneous catalysts with desired features of homogeneous catalysts: high fraction of active sites and uniform metal centers. We previously reported the synthesis of Pt‐ligand SSCs through a novel metal‐ligand self‐assembly method on MgO, CeO2, and Al2O3 supports (J. Catal. 2018, 365, 303–312). Here, we present their applications in the industrially‐relevant alkene hydrosilylation reaction, with 95 % yield achieved under mild conditions. As expected, they exhibit better metal utilization efficiency than traditional heterogeneous Pt catalysts. The comparison with commercial catalysts (Karstedt and Speier) reveals several advantages of these SSCs: higher selectivity, less colloidal Pt formation, less alkene isomerization/hydrogenation, and better tolerance towards functional groups in substrates. Despite some leaching, our catalysts exhibit satisfactory recyclability and the single‐site structure remains intact on oxide supports after reaction. Pt single‐sites were proved to be the main active sites rather than colloidal Pt formed during the reaction. An induction period is observed in which Pt sites are activated by Cl detachment and replacement by reactant alkenes. The most active species likely involves temporary detachment of Pt from ligand or support. Catalytic performance of Pt SSCs is sensitive to the ligand and support choices, enabling fine tuning of Pt sites. This work highlights the application of heterogeneous SSCs created by the novel metal‐ligand self‐assembly strategy in an industrially‐relevant reaction. It also offers a potential catalyst for future industrial hydrosilylation applications with several improvements over current commercial catalysts.

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Section: Resultsmentioning

confidence: 93%

Alkene Hydrosilylation on Oxide‐Supported Pt‐Ligand Single‐Site Catalysts

et al. 2019

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“…The prepared encapsulation materials samples 2, 3, and 4 in Table have a shore D hardness of 32, 35, and 38, respectively, which makes LED chip not susceptible to be damaged by external mechanical force. The high hardness of this encapsulation material is attributed to the high degree of crosslinking and the rigid property of the constitutive phenyl groups …”

Section: Resultsmentioning

confidence: 99%

Synthesis of an adhesion‐enhancing polysiloxane containing epoxy groups for addition‐cure silicone light emitting diodes encapsulant

Zhao

Feng

et al. 2014

Polymers for Advanced Techs

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Addition-cure silicone resin is considered as a good choice for light emitting diodes (LEDs); however, it has very poor adhesion to the substrate, which limits its practical application. A novel polysiloxane with self-adhesion ability and higher refractive index for the encapsulating of high-power LEDs is prepared and characterized. This polysiloxane containing vinyl groups, phenyl groups, and epoxy groups was synthesized by a sol-gel condensation process from methacryloxy propyl trimethoxyl silane, γ-(2,3-epoxypropoxy)propytrimethoxysilane, and diphenylsilanediol under the catalysis of an anion exchange resin. Then, the resin-type encapsulation material was prepared by hydrosilylation of methylphenyl hydrogen-containing silicone resin and the newly synthesized polysiloxane material. The novel polysiloxane was characterized by 1 H-NMR and Fourier transform infrared spectroscopy. On the basis of higher refractive index, higher transparency, excellent thermal stability, and appropriate hardness, as well as good adhesive strength between the encapsulating material and the LED lead frame (polyphthalamide), the curable silicone resin-type encapsulation material can be used as an encapsulant for LEDs.

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“…But the light output decrease due to epoxy resins discoloration and the UV-light leaking and are major issues [6,7]. In case of these reasons, UV-filter additives can be introduced into epoxy resins.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the optical properties of ZnO/epoxy resin nanocomposite: Application in the LED

Peng

Zhang

Sun

et al. 2012

2012 13th International Conference on Electronic Packaging Technology &Amp; High Density Packaging

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With development of high-power white light LED, people pay more attention to the reliability and security of packaging materials. Epoxy resins, as a main material for LED potting compound, remains to improve its thermal conductivity and ultraviolet shielding efficiency. ZnO nanoparticles were found to be well in ultraviolet (UV) absorption and good conductor of heat. In the present work, The ZnO nanoparticles were prepared by simple precipitation and calcination, presented high visible-light transparency and well ultraviolet shielding at low concentration. The ZnO/epoxy nanocomposite solution was prepared by mixing ZnO powders with epoxy resins using the ultrasonic technique, and then the composite film was prepared by spin coating technique. The results indicated that the ZnO/epoxy nanocomposite film kept high visible transparency and high ultraviolet shielding at the condition of 5wt% addition. The ZnO nanoparticles obviously enhanced UV -shielding efficiency of the epoxy resins.

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Thermally initiated cationic polymerization and properties of epoxy siloxane

Cited by 43 publications

References 13 publications

Alkene Hydrosilylation on Oxide‐Supported Pt‐Ligand Single‐Site Catalysts

Alkene Hydrosilylation on Oxide‐Supported Pt‐Ligand Single‐Site Catalysts

Synthesis of an adhesion‐enhancing polysiloxane containing epoxy groups for addition‐cure silicone light emitting diodes encapsulant

Investigation of the optical properties of ZnO/epoxy resin nanocomposite: Application in the LED

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