Polyurethane–POSS hybrids: Molecular dynamics studies

Raftopoulos, Konstantinos N.; Pandis, C.; Apekis, L.; Pissis, P.; Janowski, Bartłomiej; Pielichowski, Krzysztof; Jaczewska, Justyna

doi:10.1016/j.polymer.2009.11.067

Cited by 69 publications

(91 citation statements)

References 39 publications

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“…The amide bond is very similar to urethane and urea bonds, having in common the CO-NH sequence. Indeed, a b-relaxation with similar timescale characteristics has been observed in polyurethanes [53], in which it is typically attributed to the same type of molecular motion (i.e., water molecules bound on carbonyl groups) [54]. Interestingly, albeit it is observed by dielectric techniques, a similar relaxation occur also in NH 2 [55]and OH [52]-terminated polyethers, which denotes that the NH component, too, might have a contribution to this relaxation.…”

Section: Dynamic Mechanical Analysis (Dma)mentioning

confidence: 62%

Bio-polyamides based on renewable raw materials

Pagacz

Raftopoulos

Leszczyńska

et al. 2015

J Therm Anal Calorim

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Structural characterization of a series of novel bio-polyamides based on renewable raw materials-PA 4.10, PA 6.10, PA 10.10, and PA 10.12-was performed by Fourier transform infrared spectroscopy (FTIR) and wideangle X-ray diffraction (WAXD). Infrared spectra and the WAXD patterns indicate the coexistence of different crystalline forms, a-and c-triclinic and b-pseudohexagonal. Thermal properties in the glass transition (T g ) and melting region were then investigated using temperaturemodulated DSC (TOPEM Ò DSC). The melting point (T m ) was found to increase with increasing amide/methylene ratio in the polymer backbone, which is consistent with the increase in linear density of hydrogen bonds. Studies on the molecular dynamics by dynamic mechanical analysis show three distinct regions associated with the c-and the b-relaxation and the dynamic glass transition. TOPEM Ò DSC data reveal that at low frequency/long timescales, the materials with significantly different amide/methylene ratios have similar segmental dynamics.

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Section: Dynamic Mechanical Analysis (Dma)mentioning

confidence: 62%

Bio-polyamides based on renewable raw materials

Pagacz

Raftopoulos

Leszczyńska

et al. 2015

J Therm Anal Calorim

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“…This behavior might be related to the scarce interaction between the isobutyl-POSS and the polymer matrix, as demonstrated by yield data. Taking into account the literature findings [38][39][40], it is possible to interpret the increase of the glass transition temperature of our TPU/POSS systems on the basis of hindrance of polymer chain mobility induced by the presence of relatively bulky POSS cages. Moreover, for our polymer matrix, which consists of a hard and a soft segment phase, as reported in the literature [29], the relevant increase of T g at low temperature with increasing the POSS content can be ascribed to the portioning of silsesquioxane molecules into the soft segment phase.…”

Section: Study Of Hybrid Systems Characteristicsmentioning

confidence: 81%

On a novel method to synthesize POSS-based hybrids: An example of the preparation of TPU based system

Monticelli

Fina²,

Cavallo³

et al. 2013

Express Polym. Lett.

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Abstract.A novel method to prepare polymer/polyhedral oligomeric silsesquioxanes (POSS) hybrids by melt reactive blending is proposed in this paper, by the controlled polymer chain scission and reaction of chain ends with functional silsesquioxanes. Application to thermoplastic polyurethanes (TPU) is addressed, taking advantage of the polyurethane chain scission equilibrium reaction, leading to the formation of highly reactive isocyanate and hydroxyl chain ends. Despite the isocyanate chemistry has been widely studied for the preparation of polymer/POSS hybrids by in situ copolymerisation, the exploitation of similar chemical processes in an industrially viable and environmental friendly melt blending process is currently an open research field. In this work, the reaction in the molten state of dihydroxyl-functionalised POSS with the polyurethane chain is demonstrated to produce a TPU/POSS hybrids. The effect of POSS concentration on nanomorphology, thermal properties and surface properties is studied, showing significant changes compared to pristine TPU. In particular, an increase of glass transition temperature is observed in the presence of reactive POSS (!T up to about 10°C in the presence of 10 wt% loading). Furthermore, an increase of surface water wettability, evidenced by the decrease of water contact angle from 95° for pristine TPU to 70° in TPU containing 10"wt% of reactive POSS, is found.

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“…In this case, functionalized POSS, usually containing one or more OH groups participate in the reaction and form urethane bonds with diisocyanates leading to often complex architectures which we are going to describe in the following. The reaction may take place in the presence of small amounts of a suitable solvent such as tetrahydrofuran (THF) [30], N,N-dimethylformamide (DMF) [31], methyl ethyl ketone (MEK) [32], dimethylacetamide (DMAC) The influence of POSS nanoparticles on selected thermal properties of polyurethane-based hybrids 291 [33] or even in solvent-free environments [34,35] in which case the polyol dissolves the other components (diisocyanate and POSS). The selection of the solvent is obviously crucial for the effective reaction and good dispersion of the POSS moieties.…”

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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Polyurethane–POSS hybrids: Molecular dynamics studies

Cited by 69 publications

References 39 publications

Bio-polyamides based on renewable raw materials

Bio-polyamides based on renewable raw materials

On a novel method to synthesize POSS-based hybrids: An example of the preparation of TPU based system

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

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