Glass transition temperatures of poly(hydroxystyrene-co-vinylpyrrolidone-co-isobutylstyryl polyhedral oligosilsesquioxanes)

Xu, Hongyao; Kuo, Shiao‐Wei; Lee, Juh-Shyong; Chang, Feng‐Chih

doi:10.1016/s0032-3861(02)00402-0

Cited by 119 publications

(71 citation statements)

References 17 publications

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“…Figure 1 Figure 1d suggests a number-average molecular weight (M n ) for the PMA-POSS sample prepared in this study of 38,300 g/mol and a PDI of 1.07. Taken together, the 1 H, 13 C, and 29 Si NMR spectra and the GPC analysis confirmed the successful synthesis of PMA-POSS. Figure 2a,b displays conventional second-run DSC thermograms of PMMA and PMA-POSS, respectively, in the presence of PVPh at various weight ratios.…”

Section: Synthesis Of Pma-posssupporting

confidence: 56%

“…POSS derivatives are interesting materials because one or more of their organic groups can be functionalized for polymerization, while their remaining unreactive groups can be designed to solubilize the inorganic core and control the interfacial interactions between the POSS units and the polymer matrix. Due to their potential for advanced performance (e.g., high thermal stability; low flammability; low dielectric constant; low surface energy) relative to nonhybrid counterparts, POSS-polymer hybrid materials have attracted great interest recently [26][27][28][29][30][31][32][33][34][35]. We observed a "screening effect" in phenolic/PMMA-POSS blends arising from the tethered POSS units at the chain ends, with the inter-association equilibrium …”

Section: Introductionmentioning

confidence: 85%

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Strong Screening Effect of Polyhedral Oligomeric Silsesquioxanes (POSS) Nanoparticles on Hydrogen Bonded Polymer Blends

et al. 2014

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Abstract:In this study we used anionic living polymerization to prepare two different homopolymers: a poly(methyl methacrylate) (PMMA) and a PMMA derivative presenting polyhedral oligomeric silsesquioxane (PMA-POSS) units as its side chains. We then employed differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy, and wide-angle X-ray diffraction (WAXD) to investigate the miscibility and specific interactions of PMMA and PMA-POSS with three hydrogen bonding donor compounds: poly(vinyl phenol) (PVPh), phenolic resin, and bisphenol A (BPA). DSC revealed that all of the PVPh/PMMA, phenolic/PMMA, and BPA/PMMA blends exhibited a single glass transition temperature, characteristic of miscible systems; FTIR spectroscopic analyses revealed that such miscibility resulted from hydrogen bonding interactions between the C=O groups of PMMA and the OH groups of these three hydrogen bonding donor compounds. In contrast, all of the PVPh/PMA-POSS, phenolic/PMA-POSS, and BPA/PMA-POSS blends were immiscible: DSC revealed two OPEN ACCESSPolymers 2014, 6 927 glass transition temperatures arising from strong screening effects (FTIR spectroscopy) and high degrees of aggregation (WAXD) of the POSS nanoparticles. We propose that the value of the intramolecular screening effect (γ) should be very close to 1 for all PMA-POSS blend systems when POSS nanoparticles appear as the side chains of PMMA, such that the OH groups of the hydrogen bonding donor compounds cannot interact with the C=O groups of PMA-POSS.

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Section: Synthesis Of Pma-posssupporting

confidence: 56%

Section: Introductionmentioning

confidence: 85%

Strong Screening Effect of Polyhedral Oligomeric Silsesquioxanes (POSS) Nanoparticles on Hydrogen Bonded Polymer Blends

et al. 2014

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“…15 It has also been found that hybrids containing POSS exhibit decreased T g values in comparison with the neat polymer, and this is responsible for the increase in the free volume of the system due to the inclusion of some of the bulky POSS cages at the nanoscale level. 33 Therefore, the two competitive factors mentioned previously determine T g of the hybrids containing POSS.…”

Section: Glass-transition Behaviormentioning

confidence: 99%

Epoxy nanocomposites containing mercaptopropyl polyhedral oligomeric silsesquioxane: Morphology, thermal properties, and toughening mechanism

Shi

Chen

et al. 2008

J of Applied Polymer Sci

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A novel polyhedral oligomeric silsesquioxane (POSS) containing a mercaptopropyl group [mercaptopropyl polyhedral oligomeric silsesquioxane (MPOSS)] was synthesized via the hydrolytic condensation of g-mercaptopropyl triethoxysilane in an ethanol solution catalyzed by concentrated hydrochloric acid and was used to modify epoxyamine networks by a cocuring reaction with diglycidyl ether of bisphenol A (DGEBA). The structure, morphology, and thermal and mechanical properties of these MPOSS/DGEBA epoxy nanocomposites were studied and investigated with thermogravimetric analysis/differential thermal analysis (TGA-DTA), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). From SEM analysis, we observed that the miscibility between epoxy and POSS occurred at a relatively high POSS content, which characterized this mixture as a polymer nanocomposite system. The impact test showed that MPOSS reinforced the epoxy effectively, and the SEM study of the impact fracture surface showed that the fibrous yielding phenomenon observed was an indication of the transition of the brittle stage to a ductile stage and correlated well with the large increases in the impact strength; this was in agreement with the in situ reinforcing and toughening mechanism. The TGA-DTA analysis indicated that the MPOSS/DGEBA epoxy hybrids exhibited lower thermostability at a lower temperature but higher thermostability and higher efficiency in char formation at an elevated temperature. Differential scanning calorimetry showed that the glass transition temperature (T g ) of the MPOSS/epoxy hybrids were lower than that of the neat epoxy.

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“…Following the standard PU synthesis procedures, the reaction should be carried out in an inert gas to avoid side reactions of the diisocyanates with water. According to the type and number of functional groups at the eight corners of POSS, the structures of the hybrids formed by copolymerization can be divided into four architectures of PU/POSS composites [36]:…”

Section: Polyurethane/poss Nanocompositessynthesis and Processingmentioning

confidence: 99%

The influence of POSS nanoparticles on selected thermal properties of polyurethane-based hybrids

Pielichowski

Raftopoulos

Pielichowski

2017

J Therm Anal Calorim

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Organic-inorganic hybrid materials, prepared via chemical synthesis route or physical blending of functionalized nanofillers within polymer matrix, have gained an increased attention in the recent years. Polyhedral oligomeric silsesquioxane (POSS) nanoparticles, due to their nanometer size and functionalization possibilities, are applied as effective modifiersboth chemical and physical, for polymer matrices, including polyurethanes (PU). In this work, we describe the synthesis and processing of polyurethane/POSS hybrid nanocomposites and discuss the influence of POSS moieties on the thermal properties of PU matrices. Glass transition, the crystallinity of the soft phase, as well as the order-disorder transitions are affected by the incorporation of POSS in the polyurethane structure. Direct polymer-POSS interaction, or -indirect-due to the suppression or enhancement of microphase separation by the POSS moieties are discussed in terms of topology of the polymeric structure with the key role of POSS functionalization.

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Glass transition temperatures of poly(hydroxystyrene-co-vinylpyrrolidone-co-isobutylstyryl polyhedral oligosilsesquioxanes)

Cited by 119 publications

References 17 publications

Strong Screening Effect of Polyhedral Oligomeric Silsesquioxanes (POSS) Nanoparticles on Hydrogen Bonded Polymer Blends

Strong Screening Effect of Polyhedral Oligomeric Silsesquioxanes (POSS) Nanoparticles on Hydrogen Bonded Polymer Blends

Epoxy nanocomposites containing mercaptopropyl polyhedral oligomeric silsesquioxane: Morphology, thermal properties, and toughening mechanism

The influence of POSS nanoparticles on selected thermal properties of polyurethane-based hybrids

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