Immobilization of Poly(1,1-dimethysilacyclobutane) by Means of Anionic Ring-Opening Polymerization on Organic Nanoparticles and Reinvestigation of Crystallization

Abstract

Abstract:In the present study, the synthesis of poly(1,1-dimethylsilacyclobutane) (PDMSB) by anionic ring opening polymerization (ROP) is reinvestigated, leading to narrowly distributed molar masses (polydispersities 1.04-1.15) in the range of 2.3 to 60 kg mol −1. Investigations of thermal behavior for low molar mass PDMSB revealed an untypical multiple peaks melting phenomenon, which at first glance, seems to be of the same origin as low molar mass poly(ethylene oxide)s. Small angle X-ray scattering (SAXS) and X-ray diffraction (XRD) measurements are done, proving the fast crystallization and subsequent recrystallization for investigated low molar mass samples. Synthetic attempts are expanded to the surface-initiated anionic ROP of 1,1-dimethylsilacyclobutane (DMSB) monomer from the surface of cross-linked polystyrene (PS) nanoparticles. Novel polycarbosilanes (PCS)/organic core/shell particles are obtained, which are investigated by using transmission electron microscopy (TEM) and dynamic light scattering (DLS) experiments. First insights into the crystallization behavior OPEN ACCESSPolymers 2013, 5 285 of surface-attached PDMSB chains reveal that crystallization seems to be hindered.

Polycarbosilane-Grafted Nanoparticles: Free-Flowing Hairy Nanoparticle Liquids That Convert to Ceramic

“…For nearly 50 years, preceramic polymers have been developed and used for fabricating high-performance, nonoxide ceramics in both academic and industrial settings . Preceramic polymers have proven to be advantageous for ceramic formulation over the more common powder methods due to ease of processing, tailorable chemistry, and microstructural control. − Indeed, these macromolecules provide a diverse array of structures rich in atoms such as Si, C, O, B, and N that can yield metastable, solid-state compositions that are impossible to obtain via powder processing (e.g., SiNC). − A variety of straightforward and robust synthetic pathways have been defined for preparing preceramic polymers, including Pt(0)-catalyzed hydrosilylations, , Grignard couplings, and anionic or Pt(0)-catalyzed ring-opening polymerizations. − Synthetic design of the polymer side chains and overall backbone structure (linear, hyperbranched, block-copolymer) aids in the control of the rheological, thermal, and processing properties of the polymer. ,,, Additionally, the incorporation of cross-linkable moieties into the preceramic molecular architecture is important as the effective curing of these precursors has been noted to increase mass yields in the polymer-to-ceramic conversion process. ,,, Preceramic polymers can be processed with common polymer fabrication methods, including coating, additive manufacturing, and infiltration. − Subsequent to forming methods, the preceramic polymer is cured at ∼100–400 °C and then pyrolyzed at temperatures >600 °C . Additional heat treatments >1000 °C can be utilized to crystallize the polymer-derived ceramic and yield materials with composition and properties determined by the initial preceramic polymer …”

“…Grafting to improve particle stability in preceramic polymer matrices is an underdeveloped field. There are a range of papers detailing the grafting of poly­(dimethylsiloxane) to particles for applications in high-performance elastomers, but conversion to ceramics is not explored. , To our knowledge, only five papers exist describing the grafting of preceramic polycarbosilanes to particle surfaces, ,,− with only two reporting conversion of the particles to ceramics. , Additionally, polycarbosilane grafting typically takes place on microparticles, with the smallest particles studied being 20–40 nm gold particles . Establishing robust grafting routes for formulating dispersible preceramic-grafted particles and expanding on the characterization of such materials will elucidate novel ceramic materials with tailorable compositions and enhanced processing characteristics.…”

Surface‐Initiated Anionic Polymerization of [1]Silaferrocenophanes for the Preparation of Colloidal Preceramic Materials

“…Once redispersed in dry toluene, these double bonds on the particle surface were capable of reacting with classical initiators for anionic polymerization, e.g., butyllithium. Following this strategy, surface‐anchored styryl‐anions could be obtained, which furthermore were used to initiate an anionic polymerization . Upon addition of a solution of dimethyl[1]silaferrocenophane 2 in tetrahydrofuran (THF) to a dispersion of PS particles treated with butyllithium, poly(ferrocenyldimethylsilane) (PFDMS)‐grafted PS‐nano particles were obtained (Figure ).…”

A convenient synthesis strategy for microphase-separating functional copolymers: the cyclohydrocarbosilane tool box

“…20,21 Different approaches for the preparation of ceramic materials inclusively nanocomposites are known and excellent reviews within that field are given for example by Orilall and Wiesner 22 and other authors. [51][52][53][54][55][56][57][58][59][60] For example, Kim et al reported the block copolymerization of 1,1-dimethylsilacyclobutane (DMSB) with polystyrene. For this purpose, especially controlled or living polymerization protocols are applied.…”

“…In order to achieve these demands, especially anionic ring-opening polymerization routes starting from ring-strained cyclic carbosilane monomers has been studied by some groups. [51][52][53][54][55][56][57][58][59][60] For example, Kim et al reported the block copolymerization of 1,1-dimethylsilacyclobutane (DMSB) with polystyrene. 61 The authors succeeded in preparing microphase-separated block copolymer structures which were converted into highly-ordered silicon-carbide ceramics after thermal treatment.…”