Unperturbed dimensions of stereoregular polymers.- Reinforcement of rubber by carbon black.- Transformations of phenolic antioxidants and the role of their products in the long-term properties of polyolefins.

Properties of polymers

Composites science and technology

Fused deposition modelling (FDM) is one of the fastest-growing additive manufacturing methods used in printing fibre-reinforced composites (FRC). The performances of the resulting printed parts are limited compared to those by other manufacturing methods due to their inherent defects. Hence, the effort to develop treatment methods to overcome these drawbacks has accelerated during the past few years. The main focus of this study is to review the impact of those defects on the mechanical performance of FRC and therefore to discuss the available treatment methods to eliminate or minimize them in order to enhance the functional properties of the printed parts. As FRC is a combination of polymer matrix material and continuous or short reinforcing fibres, this review will thoroughly discuss both thermoplastic polymers and FRCs printed via FDM technology, including the effect of printing parameters such as layer thickness, infill pattern, raster angle and fibre orientation. The most common defects on printed parts, in particular, the void formation, surface roughness and poor bonding between fibre and matrix, are explored. An inclusive discussion on the effectiveness of chemical, laser, heat and ultrasound treatments to minimize these drawbacks is provided by this review.

FDM-Based 3D Printing of Polymer and Associated Composite: A Review on Mechanical Properties, Defects and Treatments.

The effects of confinement on glass transition temperature (Tg) and physical aging are measured in polystyrene (PS), poly(methyl methacrylate) (PMMA), and poly(2-vinyl pyridine) (P2VP) nanocomposites containing 10- to 15-nm-diameter silica nanospheres or 47-nm-diameter alumina nanospheres. Nanocomposites are made by spin coating films from sonicated solutions of polymer, nanofiller, and dye. The Tgs and physical aging rates are measured by fluorescence of trace levels of dye in the films. At 0.1–10 vol % nanofiller, Tg values can be enhanced or depressed relative to neat, bulk Tg (Tg,bulk) or invariant with nanofiller content. For alumina nanocomposites, Tg increases relative to Tg,bulk by as much as 16 K in P2VP, decreases by as much as 5 K in PMMA, and is invariant in PS. By analogy with thin polymer films, these results are explained by wetted P2VP–nanofiller interfaces with attractive interactions, nonwetted PMMA–nanofiller interfaces (free space at the interface), and wetted PS–nanofiller interfaces lacking attractive interactions, respectively. The presence of wetted or nonwetted interfaces is controlled by choice of solvent. For example, 0.1–0.6 vol % silica/PMMA nanocomposites exhibit Tg enhancements as large as 5 K or Tg reductions as large as 17 K relative to Tg,bulk when films are made from methyl ethyl ketone or acetic acid solutions, respectively. A factor of 17 reduction of physical aging rate relative to that of neat, bulk P2VP is demonstrated in a 4 vol % alumina/P2VP nanocomposite. This suggests that a strategy for achieving nonequilibrium, glassy polymeric systems that are stable or nearly stable to physical aging is to incorporate well-dispersed nanoparticles possessing attractive interfacial interactions with the polymer. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2935–2943, 2006

http://absimage.aps.org/image/MAR06/MWS_MAR06-2005-001949.pdf

Polymer-Nanoparticle Interfacial Interactions in Polymer Nanocomposites: Confinement Effects on Glass Transition Temperature and Suppression of Physical Aging.

The series "Advances in Intelligent Systems and Computing" contains publications on theory, applications, and design methods of Intelligent Systems and Intelligent Computing. Virtually all disciplines such as engineering, natural sciences, computer and information science, ICT, economics, business, e-commerce, environment, healthcare, life science are covered. The list of topics spans all the areas of modern intelligent systems and computing such as: computational intelligence, soft computing including neural networks, fuzzy systems, evolutionary computing and the fusion of these paradigms, social intelligence, ambient intelligence, computational neuroscience, artificial life, virtual worlds and society, cognitive science and systems, Perception and Vision, DNA and immune based systems, self-organizing and adaptive systems, e-Learning and teaching, human-centered and human-centric computing, recommender systems, intelligent control, robotics and mechatronics including human-machine teaming, knowledge-based paradigms, learning paradigms, machine ethics, intelligent data analysis, knowledge management, intelligent agents, intelligent decision making and support, intelligent network security, trust management, interactive entertainment, Web intelligence and multimedia.    The publications within "Advances in Intelligent Systems and Computing" are primarily proceedings of important conferences, symposia and congresses. They cover significant recent developments in the field, both of a foundational and applicable character. An important characteristic feature of the series is the short publication time and world-wide distribution. This permits a rapid and broad dissemination of research results.   Indexed by DBLP, EI Compendex, INSPEC, WTI Frankfurt eG, zbMATH, Japanese Science and Technology Agency (JST), SCImago.  All books published in the series are submitted for consideration in Web of Science.

Advances in Intelligent Systems and Computing

A series of poly(ethylene terephthalate-co-1,4-cyclohexanedimethanol terephthalate)-block-poly(tetramethylene oxide) (PETG-block-PTMO) copolymers were synthesized by means of a polycondensation process and characterized using 1H nuclear magnetic resonance (H NMR) and Fourier transform infrared spectroscopy (FTIR), that confirm the successful synthesis of the material. Differential scanning calorimetry (DSC), small – and wide-angle X-ray diffraction (SAXS and WAXS), and thermogravimetric analysis (TGA) were used in order to evaluate the influence of the block copolymers' composition and microstructure on the phase transition temperatures, thermal properties, as well as the thermooxidative and thermal stability of the PETG-block-PTMO copolymers, respectively. The mechanical properties were investigated by tensile testing and dynamic mechanical measurements (DMTA). We found that along with an increase in PTMO weight fraction, both number-average molecular weights and intrinsic visocisities increase. Moreover, an increase in the flexible segments content in PETG-block-PTMO resulted in shifting the values of glass transition temperatures toward lower ones, which was confirmed by DSC and DMTA analyses, thus affirming the miscibility of both phases. At the same time, along with an increase of PTMO flexible segments amount in the PETG-block-PTMO copolymers, the values of Young's modulus, tensile strength at yield and weight losses in lower temperatures range, i.e. 280–390 °C, decrease.

https://pubs.rsc.org/en/content/articlepdf/2017/ra/c7ra07172h

Synthesis and characterization of poly(ethylene terephthalate-co-1,4-cyclohexanedimethylene terephtlatate)-block-poly(tetramethylene oxide) copolymers

3D printing technology was developed nearly 30 years ago. One of its characteristics is that instead of removing materials, 3D printing creates 3D elements directly from CAD models, adding one layer of material on another. This offers a beneficial capability of making complex elements in terms of shape and materials, impossible to be manufactured by traditional methods. Owing to intensive research in recent years, considerable progress has been achieved in the development and commercialisation of new innovative processes of 3D printing by fused deposition modeling (FDM), including printing of composite materials. The study outlines the main methods of creating polymer composite structures using FDM technology.

/pdf/polymer-composite-manufacturing-by-fdm-3d-printing-2uewrigs88.pdf

Polymer Composite Manufacturing by FDM 3D Printing Technology

/pdf/poly-butylene-terephthalate-polylactic-acid-based-2b576299jt.pdf

Poly(butylene terephthalate)/polylactic acid based copolyesters and blends: miscibility-structure-property relationship

Ethylene vinyl acetate copolymer/halloysite nanotubes nanocomposites with enhanced mechanical and thermal properties

The properties of poly(butylene terephthalate) (PBT) based nanocomposites filled with MWCNTs (multiwall carbon nanotubes) and epoxy peroxide functionalized MWCNTs (EpMWCNTs) have been studied. The analysis was focused on the influence of EpMWCNTs on the phase structure, thermal, mechanical and electrical properties of synthesized materials. Functionalized MWCNTs were observed to be highly dispersed and well integrated in the PBT matrix. Obtained results demonstrate that the incorporation of EpMWCNTs into the PBT matrix yields materials of enhanced thermo-oxidative stability. It was found that the crystallization temperature for all the obtained nanocomposites is slightly higher than that for the neat polymer. Increasing the concentration of nanofiller in both MWCNT and EpMWCNT systems improved the mechanical properties Young’s modulus, tensile strength and fracture strain. The electrical conductivity of nanocomposites decreased due to the functionalization of MWCNTs with epoxy peroxide.

Elżbieta Piesowicz

Papers

Synthesis and characterization of poly(ethylene terephthalate-co-1,4-cyclohexanedimethylene terephtlatate)-block-poly(tetramethylene oxide) copolymers

Polymer Composite Manufacturing by FDM 3D Printing Technology

Poly(butylene terephthalate)/polylactic acid based copolyesters and blends: miscibility-structure-property relationship

Ethylene vinyl acetate copolymer/halloysite nanotubes nanocomposites with enhanced mechanical and thermal properties

Poly(butylene terephthalate/carbon nanotubes nanocomposites. Part II. Structure and properties