Multifunctional Polymer Nanocomposites Based on Thermoplastic Polyesters

Polymer nanocomposites containing carbon nanoparticles have exhibited remarkable thermal, mechanical and electrical properties. This review is concerned with a narrow sector of polymer nanocomposites, namely those based on engineering polyesters, which are of great industrial interest. The various functionalization methods of modifying carbon nanotubes and graphene derivative forms to allow interacting with polymer matrices will be summarized. Moreover, the review on the processing techniques of obtaining polymer nanocomposites with the emphasis of their effect on the final properties of the obtained material will be highlighted. The light will be also shed on the nanofiller dispersion in the polymer matrix. Finally, the opportunities and challenges in the high‐performance polymer nanocomposites will be presented

Nanocomposites Based on Thermoplastic Polyester Elastomers

The use of fillers in order to enhance the properties of polymers has been already well documented. Fundamentally, traditional fillers were applied to reduce the cost of the final polymeric products. Moreover, most micron-sized fillers required high loading for slight properties enhancement, thus causing problems in processing and melt flow due to the high viscosity of the obtained composite. Nanofillers might constitute the answer to the requirements made to the modern polymer materials. Nanofillers in the range of 3–5 wt% achieve the same reinforcement as 20–30 wt% of micron-sized fillers. Therefore, this study presents the influence of three different types of nanofillers that differ in shape (aspect ratio) on the morphology, electrical conductivity, and thermal stability of polyester thermoplastic elastomer (TPE) matrix, by means of poly(trimethylene)-block-poly(tetramethylene oxide) copolymer (PTT-PTMO). The morphology in this copolymer consisted of semicrystalline PTT domains dispersed in the soft phase of amorphous, noncrystallisable PTMO. The PTT-PTMO copolymer has been combined with 0.5 wt% of 1D (single-walled carbon nanotubes (SWCNTs), silicon carbide (SiC) nanofibers), 2D (graphene oxide (GO), graphene nanoplatelets (GNPs)), and 3D (polyhedral oligomeric silsesquioxane (POSS)) through in situ synthesis to obtain nanocomposites (NCs) samples

Recreational Development at Pelican Lake, Minnesota: An Analysis of Factors Affecting Site Selection

In order to better predict those areas whicd\u27 have the po tential to be developed more rapidly than others, research concerning physical land use character isti ;s which determine current lakeshore patterns needs to be implemented. This study is designed to assess which physics . land use/cover characteristics have affected lake home development at Peli can Lake in north central Minnesota. Analysis involves the interpretation of aerial photo graphs from the years 1939, I960, 1969, and 1978 which were used to map location and extent of land use/cover change in the Pelican Lake area. Archival data is utilized in order to determine number and location of recreational homes ex isting on the shoreline of Pelican Lake. Finally, correla tion and regression techniques are used in order to ascer tain relationships between the physical parameters of the watershed and location of lakeshore homes. Length of shoreline is found to be the leading indicator in number of homes in each section bordering Pelican Lake. Distance to nearest improved road also proves to be a sig nificant factor. Of the land use/cover data obtained from aerial photographs, only acres of that land covered by water and.acres in Pelican. Lake are determined to be of signifi cance in location of lakeshore homes

Thin polymer films based on poly(vinyl alcohol) containing graphene oxide and reduced graphene oxide with functional properties

10 pags., 7 figs., 2 tabs.In this article, the effect of the addition of graphene oxide (GO) and reduced graphene oxide (rGO) on the mechanical properties, thermal stability, and electrical conductivity of polyvinyl alcohol (PVA) has been investigated. Different weight percentages of nanofillers ranging from 0.5 to 5 wt% have been combined with PVA. The ultrasonic technique has been applied to disperse nanofillers in the PVA solution. The nanocomposite films have been prepared via solution casting technique and the dispersion of nanofillers into the PVA has been studied through optical microscopy. The microstructure, crystallization behavior, and interfacial interaction were characterized through X-ray diffraction and Fourier transform infrared spectroscopy. Differential scanning calorimetry (DSC) and thermogravimetric analysis have been applied to study the thermal properties of the prepared nanocomposites. The DSC results revealed that the crystallization temperature and melting temperature were enhanced in the presence of GO nanofiller. Besides, the tensile strength at break was improved along with the addition of GO; however, elongation at break for PVA/GO and PVA/rGO was diminished. Moreover, all specimens showed insulating behavior and the only sample was electrically conducting, which contain a high amount of rGO (5 wt%).Spanish Ministry of Science and Innovation, Grant/Award Number:PID2019-107514GB-I0

Is the sub-glass temperature relaxation of furan-based polymers related to their high gas barrier properties?

11th Conference on Broadband Dielectric Spectroscopy and its Applications (BDS2022), Donostia/San Sebastián, 04.Sep - 09.Sep 2022. -- Presentación con 25 diapositivasPoly(alkylene 2,5-furanoate)s, (PAF)s, are fully biobased homopolyesters based on 2,5-furandicarboxylic acid that have recently emerged as promising alternative to petroleum based poly(alkylene terephthalate)s. In addition to a lower production carbon footprint poly(alkylene 2,5-furanoate)s have received significant attention due to their outstanding gas barrier properties in comparison to traditional poly aromatic esters [1]. The influence of chain dynamics on barrier properties has also devoted some attention. Dielectric spectroscopy experiments performed in poly(trimethylene 2,5-furanoate) revealed that the subambient relaxation, below its glass transition temperature, exhibited an inhibition of the mode corresponding to the ester oxygen linked to the aliphatic subunit which efficiently relaxes in the poly(trimethylene terephthalate) counterpart [2]. Fourier Transform Infrared (FT-IR) spectroscopy can provide precise information of intra-molecular motions at the molecular level [3]. By evaluating the vibrational frequencies and the corresponding oscillator, strength from the IR spectra information about the intra-molecular dynamics can be available. In this study, we present a combined IR spectroscopy and BDS study focused on the sub-glass temperature molecular dynamics of poly(trimethylene 2,5-furanoate) in comparison to that of poly(trimethylene terephthalate) in order to shed light on the influence the dynamics on the barrier properties of Poly(alkylene 2,5-furanoate)s.The authors gratefully acknowledge the financial support of the Spanish Ministry of Science and Innovation (MICINN) through PID2019-107514GB-I00 / AEI / 10.13039/501100011033

Inter and intra molecular dynamics in poly(trimethylene 2,5-furanoate) as revealed by infrared and Broadband Dielectric Spectroscopies

9 pags., 9 figs., 2 tabs.Infrared spectroscopy (IR) and Broadband Dielectric Spectroscopy (BDS) experiments have been performed in poly(trimethylene 2,5-furanoate)(PTF) and poly(trimethylene terephthalate)(PTT) below their glass transition temperatures. The BDS experiments reveal a richer inter-molecular dynamic for PTT as characterized by a multimodal β relaxation in contrast with the monomodal one exhibited by PTF. The evolution with temperature of comparable IR absorption bands is very similar for PTF and PTT and shows small shifts in wavenumbers towards lower values, with exception of the band related to the stretching mode of the carbonyl group. In addition, a significant difference appears in the shape of the bands associated with the –C[dbnd]O stretching. While for PTT the absorption feature is comprised of a single component, that for PTF exhibits several components suggesting the presence of hydrogen bonds. This effect may be responsible for the monomodal shape of the β relaxation of PTF since a higher degree of intramolecular coupling between the furan ring and the rest of the monomer is expected. Density Functional Theory (DFT) calculations support the experimental results revealing that as temperature increases an increment of the syn conformations of the 2,5-furandicarboxylic acid (FDCA) moiety is likely to occur in the amorphous state. The energy gain from more stable anti to less stable syn isomers can be compensated by the formation of hydrogen bonds between interchain FDCA moieties in syn conformations. This effect may cause additional hindrance to the intermolecular dynamics of the dielectric β relaxation. It is conceivable that the hindrance exhibited by PTF in both intra and inter-molecular dynamics may play a role in the reduction of gas diffusion and permeability of PTF in comparison with PTT.Grants PID2019-107514 GB-I00/AEI/10.13039/501100011033 and PID2019-106125 GB-I00/AEI/10.13039/501100011033 funded by MCIN/AEI/10.13039/501100011033 and by “ ERDF A way of making Europe”. GS acknowledges grant RYC2020-029810-I funded by MCIN/ AEI/10.13039/501100011033 and by “ ESF Investing in your future”. SP would like to thank for financial support from the National Science Centre within project SONATA no 2018/31/D/ST8/00792.

Laterally-resolved mechanical and tribological properties of laser-structured polymer nanocomposites

[EN]In this work, we report on a detailed quantitative nanomechanical mapping of free-standing films of poly(ethylene terephthalate) (PET) and the composite PET/expanded graphite (EG) with 0.4% in weight of the nanoadditive, and of these materials nanostructured by laser irradiation. By using atomic force microscopy, we obtained simultaneously the topography, surface elastic modulus and adhesion force maps of the materials. Young's modulus images exhibited higher values for the composite in comparison to those of the neat polymer and for the nanostructured films in contrast to the non-nanostructured ones. Additionally, we explored the tribological properties of these systems at the nanoscale. Using lateral force microscopy, we observed a decrease in the friction coefficient for the nanocomposite as compared to the neat polymer, while quantifying an increase for both laser-structured samples. Our results are discussed taking into consideration the possible changes that the samples might undergo during processing, as well as the changes imposed by the complex geometry of the nanometric features in these laterally-resolved mechanical measurements

How should the completeness and quality of curated nanomaterial data be evaluated?

Nanotechnology is of increasing significance. Curation of nanomaterial data into electronic databases offers opportunities to better understand and predict nanomaterials' behaviour. This supports innovation in, and regulation of, nanotechnology. It is commonly understood that curated data need to be sufficiently complete and of sufficient quality to serve their intended purpose. However, assessing data completeness and quality is non-trivial in general and is arguably especially difficult in the nanoscience area, given its highly multidisciplinary nature. The current article, part of the Nanomaterial Data Curation Initiative series, addresses how to assess the completeness and quality of (curated) nanomaterial data. In order to address this key challenge, a variety of related issues are discussed: the meaning and importance of data completeness and quality, existing approaches to their assessment and the key challenges associated with evaluating the completeness and quality of curated nanomaterial data. Considerations which are specific to the nanoscience area and lessons which can be learned from other relevant scientific disciplines are considered. Hence, the scope of this discussion ranges from physicochemical characterisation requirements for nanomaterials and interference of nanomaterials with nanotoxicology assays to broader issues such as minimum information checklists, toxicology data quality schemes and computational approaches that facilitate evaluation of the completeness and quality of (curated) data. This discussion is informed by a literature review and a survey of key nanomaterial data curation stakeholders. Finally, drawing upon this discussion, recommendations are presented concerning the central question: how should the completeness and quality of curated nanomaterial data be evaluated