Molecular Chemistry and Engineering of Boron-Modified Polyorganosilazanes as New Processable and Functional SiBCN Precursors.
A series of boron-modified polyorganosilazanes was synthesized from a poly(vinylmethyl-co-methyl)silazane and controlled amounts of borane dimethyl sulfide. The role of the chemistry behind their synthesis has been studied in detail by using solid-state NMR spectroscopy, FTIR spectroscopy, and elemental analysis. The intimate relationship between the chemistry and the processability of these polymers is discussed. Polymers with low boron contents displayed appropriate requirements for facile processing in solution, such as impregnation of host carbon materials, which resulted in the design of mesoporous monoliths with a high specific surface area after pyrolysis. Polymers with high boron content are more appropriate for solid-state processing to design mechanically robust monolith-type macroporous and dense structures after pyrolysis. Boron acts as a crosslinking element, which offers the possibility to extend the processability of polyorganosilazanes and suppress the distillation of oligomeric fragments in the low-temperature region of their thermal decomposition (i.e., pyrolysis) at 1000 °C under nitrogen. Polymers with controlled and high ceramic yields were generated. We provide a comprehensive mechanistic study of the two-step thermal decomposition based on a combination of thermogravimetric experiments coupled with elemental analysis, solid-state NMR spectroscopy, and FTIR spectroscopy. Selected characterization tools allowed the investigation of specific properties of the monolith-type SiBCN materials.
IEM (Institut Europeen des Membranes), UMR 5635 (CNRS-ENSCM-UM), Universite Montpellier, Place E. Bataillon, 34095, Montpellier, France.
Antoine
A
Viard
IEM (Institut Europeen des Membranes), UMR 5635 (CNRS-ENSCM-UM), Universite Montpellier, Place E. Bataillon, 34095, Montpellier, France.|Science des Procédés Céramiques et de Traitements de Surface (SPCTS), UMR CNRS 7315, Centre Européen de la Céramique, 12 rue Atlantis, 87068, Limoges Cedex, France.
Diane
D
Fonblanc
IEM (Institut Europeen des Membranes), UMR 5635 (CNRS-ENSCM-UM), Universite Montpellier, Place E. Bataillon, 34095, Montpellier, France.|University of Bordeaux, Laboratoire des Composites ThermoStructuraux (LCTS), UMR 5801, CNRS-Herakles (Safran)-CEA-UBx 3, Allée de La Boétie, 33600, Pessac, France.
Marion
M
Schmidt
IEM (Institut Europeen des Membranes), UMR 5635 (CNRS-ENSCM-UM), Universite Montpellier, Place E. Bataillon, 34095, Montpellier, France.
Abhijeet
A
Lale
Sorbonne Universités, UPMC Univ Paris 06, CNRS, Collège de France, UMR 7574, Chimie de la Matière Condensée de Paris, 75005, Paris, France.
Chrystelle
C
Salameh
Sorbonne Universités, UPMC Univ Paris 06, CNRS, Collège de France, UMR 7574, Chimie de la Matière Condensée de Paris, 75005, Paris, France.
Anne
A
Soleilhavoup
IEM (Institut Europeen des Membranes), UMR 5635 (CNRS-ENSCM-UM), Universite Montpellier, Place E. Bataillon, 34095, Montpellier, France.|Laboratoire de Matériaux Céramiques et Procédés Associés LMCPA, UPRES EA 2443, UVHC-ISTV, 59600, Maubeuge, France.
Mélanie
M
Wynn
Laboratoire de Matériaux Céramiques et Procédés Associés LMCPA, UPRES EA 2443, UVHC-ISTV, 59600, Maubeuge, France.
Philippe
P
Champagne
IEM (Institut Europeen des Membranes), UMR 5635 (CNRS-ENSCM-UM), Universite Montpellier, Place E. Bataillon, 34095, Montpellier, France.
Sophie
S
Cerneaux
Sorbonne Universités, UPMC Univ Paris 06, CNRS, Collège de France, UMR 7574, Chimie de la Matière Condensée de Paris, 75005, Paris, France.
Florence
F
Babonneau
University of Bordeaux, Laboratoire des Composites ThermoStructuraux (LCTS), UMR 5801, CNRS-Herakles (Safran)-CEA-UBx 3, Allée de La Boétie, 33600, Pessac, France.
Georges
G
Chollon
Science des Procédés Céramiques et de Traitements de Surface (SPCTS), UMR CNRS 7315, Centre Européen de la Céramique, 12 rue Atlantis, 87068, Limoges Cedex, France.
Fabrice
F
Rossignol
Sorbonne Universités, UPMC Univ Paris 06, CNRS, Collège de France, UMR 7574, Chimie de la Matière Condensée de Paris, 75005, Paris, France.
Christel
C
Gervais
IEM (Institut Europeen des Membranes), UMR 5635 (CNRS-ENSCM-UM), Universite Montpellier, Place E. Bataillon, 34095, Montpellier, France.
Samuel
http://orcid.org/0000-0001-5865-0047
S
Bernard
boron; polysilazanes; preceramic polymers; precursor chemistry; processability; pyrolysis