UV‐activated hydrosilation reaction for silicone polymer crosslinking

Ligorio

et al. 2016

Macro Materials & Eng

Silicone materials are widely used in many fields such as electrical or food industries and their consumption is constantly growing. They are generally cured by vulcanization reaction for long time at high temperatures which requires high energy consumption. The possibility to achieve the polymerization of silicone rubbers by UV‐activation promotes the reduction of both time and temperature leading to an impressive energy saving. Indeed, this process is more than 30 times faster than the thermal one. Moreover, the properties of the two resulting materials are comparable, indicating that the low time of UV‐activated hydrosilation reaction is suitable for the formation of crosslinked silicone polymers.

Section: Dark-curingsupporting

confidence: 83%

Impressive Rate Raise of the Hydrosilation Reaction Through UV‐Activation: Energy and Time Saving

Ligorio

et al. 2016

Macro Materials & Eng

“…In order to evaluate the presence of a dark curing (that is, the proceeding of the curing without UV light), silane conversion was followed by FTIR analyses after different times of irradiation. A significant increase of the Si-H conversion in the dark for the Pt(acac) 2 catalyst was previously reported [13] and was attributed to the slow conversion of the homogeneous hydrosilation catalyst (formed under UV irradiation) into a less active heterogeneous catalyst, similar to the one formed upon thermal hydrosilation reaction. [7,13,14] Mixtures containing equimolar amount of PDMS-V and MH-PDMS with 250 ppm (Figure 2a) and 1 000 ppm ( Figure 2b) of (Me-Cp)Pt(Me) 3 catalyst were investigated.…”

Section: Evaluation Of the Dark Curingsupporting

confidence: 66%

“…A significant increase of the Si-H conversion in the dark for the Pt(acac) 2 catalyst was previously reported [13] and was attributed to the slow conversion of the homogeneous hydrosilation catalyst (formed under UV irradiation) into a less active heterogeneous catalyst, similar to the one formed upon thermal hydrosilation reaction. [7,13,14] Mixtures containing equimolar amount of PDMS-V and MH-PDMS with 250 ppm (Figure 2a) and 1 000 ppm ( Figure 2b) of (Me-Cp)Pt(Me) 3 catalyst were investigated. The mixtures were coated on a SiC substrate with a thickness of 50 mm and then irradiated with UV light for 10, 30, and 60 s, respectively.…”

Section: Evaluation Of the Dark Curingsupporting

confidence: 66%

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A Comparison of the Reactivity of Two Platinum Catalysts for Silicone Polymer Cross‐Linking by UV‐Activated Hydrosilation Reaction

Macro Reaction Engineering

Meier

et al. 2015

The synthesis of silicon compounds is mainly achieved by room temperature or hightemperature vulcanization reaction. Several transition-metal organometallic compounds such as platinum complexes can be used as catalysts to accelerate the thermal reaction. Moreover, these compounds are found to be also efficient for the cross-linking of silicone polymer by UV-activated reaction. In particular, cyclopentadienyl platinum complexes are considered as catalysts that can sustain an extremely high photochemical reaction after UV-light excitation. The reactivity of these catalysts (in particular the trimethyl(methylcyclopentadienyl) (IV) complex (Me-Cp)Pt(Me) 3 ) for the photopolymerization of silicon polymer compounds is evaluated and compared with the most common bis(acetylacetonate)platinum (II) catalyst used for the UV-activated hydrosilation reaction.

“…The curing of the polymeric matrix was achieved by UV‐induced hydrosilation reaction, which we investigated in a previous paper . It was also demonstrated that the hydrosilation reaction proceeds by a thermal‐frontal mechanism allowing to have 3 cm thick homogeneous unfilled sample .…”

Section: Introductionmentioning

confidence: 99%

UV‐cured silicone composites obtained via hydrosilation and in‐situ generation of inorganic particles

Polymer Engineering & Sci

Meier

et al. 2015

The in situ generation of particles is an efficient way to prepare organic‐inorganic hybrid materials. This approach has been widely used to enhance the dispersion within the matrix and therefore to improve the composites’ properties. This method was used in the present paper to produce silicone composites. The crosslinking of the polymer matrix was achieved by hydrosilation reaction that is typically the addition of a Si‐H bond across a double bond, in the presence of a platinum catalyst. The generation of silica particles was carried out prior the hydrosilation reaction. We previously demonstrated that this usually thermally activated reaction can also be induced under UV‐light and that a front propagation allows the formation of thick unfilled samples. However, the presence of inorganic particles directly dispersed in the matrix lead to a reduction of thickness curability. That is the reason why the addition of particles by sol‐gel process is studied in the present article. The lower dimension and better dispersion of the particles within the material promote the formation of thicker cured composites. The effect of the silica precursor's amount on the system's reactivity was evaluated and samples thick up to 2 cm were obtained with the most suitable conditions of reaction. POLYM. ENG. SCI., 56:3–8, 2016. © 2015 Society of Plastics Engineers