Polyhedral Oligomeric Silsesquioxanes (POSS)-Containing Nanohybrid Polymers

Pielichowski, Krzysztof; Njuguna, James; Janowski, Bartłomiej; Pielichowski, Jan

doi:10.1007/12_077

Cited by 370 publications

(298 citation statements)

References 201 publications

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“…However, their isolation from the crude reaction mixture is difficult and the product is obtained with a very low yield. For example, a mixture of four stereoisomers was prepared by hydrolysis of the hydride precursor, [MeSi(H)O] 4 catalyzed by Pd/C act [13]. Cis-trans-cis-tetraol was isolated using specific recrystallization protocol with about 8 % yield and polycondensed in the presence of K 2 CO 3 as a catalyst, resulting in a ladder-like product of cis-syndiotactic conformation [13,25].…”

Section: Monomer Synthesis and Polycondensationmentioning

confidence: 99%

“…The number of structural defects in polysilsesquioxane materials increases with increasing molecular weight until random networks are formed [3]. The resulting degree of randomness depends both on the nature of the substituent at the silicon atom and the reaction conditions [4]. Several synthetic protocols for the preparation of ladder polysilsesquioxanes have been developed more recently [5,6].…”

Section: Introductionmentioning

confidence: 99%

“…Well-defined ladder poly(methylphenylsilsesquioxanes) were obtained as well via nonhydrolytic condensation [10]. Polysilsesquioxanes can be also obtained by condensation of specific tetrasiloxane precursors such as disiloxanes [RSiX 2 ] 2 O and cyclotetrasiloxanes [RXSiO] 4 that help the formation of a true ladder structure. Linear ladder silsesquioxanes have been synthesized from sila-functionalized [RSiXO] 4 (R = Me, Ph; X = H, OEt, NCO) [11,12].…”

Section: Introductionmentioning

confidence: 99%

“…Polysilsesquioxanes can be also obtained by condensation of specific tetrasiloxane precursors such as disiloxanes [RSiX 2 ] 2 O and cyclotetrasiloxanes [RXSiO] 4 that help the formation of a true ladder structure. Linear ladder silsesquioxanes have been synthesized from sila-functionalized [RSiXO] 4 (R = Me, Ph; X = H, OEt, NCO) [11,12]. Polycondensation of all-cis or cis-trans-cis isomers of cyclic tetrasilanols [13] or isocyanates [14] gives linear polymers of high regularity and defined tacticity.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of Ladder Silsesquioxanes by in situ Polycondensation of Cyclic Tetravinylsiloxanetetraols

Kowalewska

Nowacka

2014

Silicon

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Functionalized tetrahydroxy-cyclotetrasiloxanes are very attractive precursors of tetrasiloxane ring systems in linear silsesquioxanes (LPSQs). Vinyl groups are especially important since they can be employed for various chemical transformations (e.g. hydrosilylation, metathesis reactions, thiol-ene addition). However, isolation of such highly reactive species bearing small side substituents at silicon atoms with high yield is challenging. We overcame the problem by in situ condensation of 2,4,6,8-tetrahydroxy-2,4,6,8-tetravinyl-cyclotetrasiloxanes, derived from potassium organosiloxanolateOligomeric LPSQ materials having a siloxane backbone with ladder structure and functionalized with side vinyl groups were thus prepared. Hexamethyldisilazane was employed for chain termination. The liquid materials show remarkably good solubility in organic solvents. They were isolated and characterized using spectroscopic methods. Information on their structure and molecular masses was derived from MALDI-TOF and MALLS measurements. Size exclusion chromatography (RI detection, volume of elution measurements) was also used. The products were characterized by wide-angle X-Ray diffraction measurements (WAXS) and their thermal characteristics (TGA and DSC) were obtained.

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Section: Monomer Synthesis and Polycondensationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Synthesis of Ladder Silsesquioxanes by in situ Polycondensation of Cyclic Tetravinylsiloxanetetraols

Kowalewska

Nowacka

2014

Silicon

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“…1,8 The reactive functional groups permit the POSS cages to be a graftable and polymerisable nanoparticle. 4 The POSS materials are typically prepared by a process that involves crystallizing the target regular cage structured POSS molecules from solution.…”

Section: Introductionmentioning

confidence: 99%

Impact of End-Tethered Polyhedral Nanoparticles on the Mobility of Poly(dimethylsiloxane)

et al. 2015

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A series of dumbbell-shaped nanocomposite materials of poly(dimethylsiloxanes) (PDMSs) and polyhedral oligomeric silsesquioxanes (POSSs) were synthesized through hydrosilylation reactions of allyl-and vinyl-POSS and hydrideterminated PDMS. The chemical structures of the dumbbellshaped materials, so-called POSS-PDMS-POSS triblocks, were characterized by 1 H NMR and FT-IR spectroscopy. The molecular weights of the triblock polymers were determined by gel permeation chromatography (GPC). Their size was analyzed by small-angle neutron scattering (SANS) and pulsed-field gradient stimulated echo (PFG STE) NMR experiments. The impact of POSS on the molecular mobility of the PDMS middle chain was observed by using 1 H spin−spin (T 2 ) relaxation NMR. In contrast to the PDMS melts, the triblocks showed an increase in mobility with increasing molecular weight over the range studied due to the reduced relative concentration of constraints imposed by the end-tethered nanoparticles. The triblock systems were used to compare the impact of tethered nanoparticles on the mobility of the linear component compared to the mobility of the polymer in conventional blended nanocomposites. The tethered nanoparticles were found to provide more reinforcement than physically dispersed particles especially at high molecular weights (low particle concentration). The physical blends showed an apparent percolation threshold behavior.

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Wide‐Angle X‐ray Diffraction and Small‐Angle X‐ray Scattering Studies of Rubber Nanocomposites

Causin

2010

Rubber Nanocomposites

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Polyhedral Oligomeric Silsesquioxanes (POSS)-Containing Nanohybrid Polymers

Cited by 370 publications

References 201 publications

Synthesis of Ladder Silsesquioxanes by in situ Polycondensation of Cyclic Tetravinylsiloxanetetraols

Synthesis of Ladder Silsesquioxanes by in situ Polycondensation of Cyclic Tetravinylsiloxanetetraols

Impact of End-Tethered Polyhedral Nanoparticles on the Mobility of Poly(dimethylsiloxane)

Wide‐Angle X‐ray Diffraction and Small‐Angle X‐ray Scattering Studies of Rubber Nanocomposites

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