370
14.6.3 Crosslinking of Silicone Elastomers and Rubbers
with PMHS
Almost half of the world’s production of silicones belongs to silicone elastomers
and rubbers (Rościszewski 1964; Peter and Kniege 1968; Karlin et al. 1973; Schätz
1975; Dolgov et al. 1975; Arkles 1983; Hardman and Torkelson 1989; Klosowski
1989; Lower and Klosowski 1994; Bontems et al. 1993; Pujol et al. 1995; White
1995; Chruściel 1999c).
Prior to vulcanization, SRs have a linear structure and contain up to several thousand silicon atoms in their chains. PMHS are often used as crosslinking agents for
SR systems based on dehydrocondensation or polyaddition reactions. In first systems, during the vulcanization, hydrogen gas is released, which in thicker layers
leads to formation of microporous structures (Chruściel and Leśniak 2011, Chruściel
et al. 2011c). The vulcanization with PMHS requires the use of catalysts (usually tin
or Pt compounds). The time of crosslinking of two- and three-component silicones
depends on the type of RT ‘cold’ vulcanized (RTV) rubbers and the amount of catalyst. Keeping this in view, Takago et al. (1993) prepared vulcanized SRs by hydrosilylation of α,ω-divinyl-PDMS with α,ω-dihydrosiloxanes in the presence of the Pt
catalyst. Microcellular polysiloxane materials were also prepared from a concentrated inverse emulsion by hydrosilylation reaction of vinylsiloxane with H-siloxanes
(Grosse et al. 2008).
Carbon nanofiber (CNF)/PDMS-based nanocomposites (NCs) were prepared by
anionic ROP of D 4 in presence of CNF. A maximum increase in mechanical properties was observed for amine-modified CNF/hydroxyl PDMS NCs prepared in situ.
For 8 phr filler content, tensile strength (TS) increased by 370%, and tensile modulus increased of 515% compared with the starting elastomer, while unmodified
CNF/hydroxyl PDMS NCs prepared in situ showed an increase of 141 °C in temperature of maximum degradation (Roy and Bhowmick 2012).
Different PDMS nanocomposite membranes prepared from PMVS and PMHS,
and filled with nanosilica particles were used to improve the pervaporation
performance in recovery of iso-propanol from water mixtures (Shirazi et al. 2012).
Vinyl-terminated PDMS, crosslinked with PMHS were useful as dental materials
(Hatzi et al. 2012). Polysiloxane elastomers obtained via crosslinking of PMVS
with PMHS were used as matrices filled with metallic Pt particles (Stochmal et al.
2016). SRs obtained by crosslinking of Me 3 SiO(MeHSiO) n SiMe 3 (n ≈ 38) with
D
Vi 4 were pyrolized into SiOC glasses, giving high ceramic yields (87–93 wt.%),
depending on the stoichiometry of the substrates (Radovanovic et al. 1999).
Si(OSiMe 2 H) 4 is often applied as the crosslinker for silicone elastomers (Li et al.
2006; Vaenkatesan et al. 2006). Zhao and Feng (2003) described the application of
the branched multifunctional hydrosiloxane resins as crosslinkers for additioncured silicone elastomers. Vinylsilicone elastomers, crosslinked with PMHS and
TEOS (3:1, v/v), under plasma action, showed a very good adhesion to stainless
steel (Nwankire et al. 2009).
J. J. Chruściel
14.6.3 Crosslinking of Silicone Elastomers and Rubbers
with PMHS
Almost half of the world’s production of silicones belongs to silicone elastomers
and rubbers (Rościszewski 1964; Peter and Kniege 1968; Karlin et al. 1973; Schätz
1975; Dolgov et al. 1975; Arkles 1983; Hardman and Torkelson 1989; Klosowski
1989; Lower and Klosowski 1994; Bontems et al. 1993; Pujol et al. 1995; White
1995; Chruściel 1999c).
Prior to vulcanization, SRs have a linear structure and contain up to several thousand silicon atoms in their chains. PMHS are often used as crosslinking agents for
SR systems based on dehydrocondensation or polyaddition reactions. In first systems, during the vulcanization, hydrogen gas is released, which in thicker layers
leads to formation of microporous structures (Chruściel and Leśniak 2011, Chruściel
et al. 2011c). The vulcanization with PMHS requires the use of catalysts (usually tin
or Pt compounds). The time of crosslinking of two- and three-component silicones
depends on the type of RT ‘cold’ vulcanized (RTV) rubbers and the amount of catalyst. Keeping this in view, Takago et al. (1993) prepared vulcanized SRs by hydrosilylation of α,ω-divinyl-PDMS with α,ω-dihydrosiloxanes in the presence of the Pt
catalyst. Microcellular polysiloxane materials were also prepared from a concentrated inverse emulsion by hydrosilylation reaction of vinylsiloxane with H-siloxanes
(Grosse et al. 2008).
Carbon nanofiber (CNF)/PDMS-based nanocomposites (NCs) were prepared by
anionic ROP of D 4 in presence of CNF. A maximum increase in mechanical properties was observed for amine-modified CNF/hydroxyl PDMS NCs prepared in situ.
For 8 phr filler content, tensile strength (TS) increased by 370%, and tensile modulus increased of 515% compared with the starting elastomer, while unmodified
CNF/hydroxyl PDMS NCs prepared in situ showed an increase of 141 °C in temperature of maximum degradation (Roy and Bhowmick 2012).
Different PDMS nanocomposite membranes prepared from PMVS and PMHS,
and filled with nanosilica particles were used to improve the pervaporation
performance in recovery of iso-propanol from water mixtures (Shirazi et al. 2012).
Vinyl-terminated PDMS, crosslinked with PMHS were useful as dental materials
(Hatzi et al. 2012). Polysiloxane elastomers obtained via crosslinking of PMVS
with PMHS were used as matrices filled with metallic Pt particles (Stochmal et al.
2016). SRs obtained by crosslinking of Me 3 SiO(MeHSiO) n SiMe 3 (n ≈ 38) with
D
Vi 4 were pyrolized into SiOC glasses, giving high ceramic yields (87–93 wt.%),
depending on the stoichiometry of the substrates (Radovanovic et al. 1999).
Si(OSiMe 2 H) 4 is often applied as the crosslinker for silicone elastomers (Li et al.
2006; Vaenkatesan et al. 2006). Zhao and Feng (2003) described the application of
the branched multifunctional hydrosiloxane resins as crosslinkers for additioncured silicone elastomers. Vinylsilicone elastomers, crosslinked with PMHS and
TEOS (3:1, v/v), under plasma action, showed a very good adhesion to stainless
steel (Nwankire et al. 2009).
J. J. Chruściel