Special Issue "Processing-Structure-Properties Relationships in Polymers II"

A special issue of Polymers (ISSN 2073-4360). This special issue belongs to the section "Polymer Analysis".

Deadline for manuscript submissions: 20 November 2020.

Special Issue Editors

Prof. Dr. Roberto Pantani
Website
Guest Editor
Industrial Engineering Department, University of Salerno, I-84084 Fisciano (Salerno), Italy
Interests: analysis and simulation of injection moulding of thermoplastics; structure development in polymer processing; volume accuracy and stability in polymer processing; processing and degradation of biodegradable polymers
Special Issues and Collections in MDPI journals
Dr. Sara Liparoti
Website
Guest Editor
Industrial Engineering Department, University of Salerno, I-84084 Fisciano (Salerno), Italy
Interests: Advanced Injection molding, polymer structure development during injection molding, advanced characterization of the mechanical properties within injection molding objects; tuning of surface topography and properties by injection molding; rheology of hydrogels; supercritical fluid based processes
Special Issues and Collections in MDPI journals

Special Issue Information

Dear Colleagues,

The extraordinary capacity of plastics to modify their properties according to a particular structure could be a difficulty, but also an opportunity, and it is one of the keys to the success of this class of materials.
The same polymer can be transparent or opaque, rigid or flexible, permeable or impermeable, according to the spatial organization of its macromolecules or of a particular filler.
Obviously, the key to taking profit of this peculiar capacity of plastics relies on our capacity of inducing, by means of a suitable processing, that specific spatial organization.
The aim of this Special Issue is to collect a number of research or review papers which can depict the state of the art on the possible correlations between processing variables, obtained structure and the special property, which this structure induces on the plastic part. We would welcome contributions dealing with the related research fields, and I do hope that this stimulating subject will induce you to submit a manuscript to this Special Issue.

Prof. Dr. Roberto Pantani
Dr. Sara Liparoti
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Polymers is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • effect of polymer processing on resulting morphology and/or properties mechanical
  • optical
  • thermal
  • transport properties of polymers induced by particular processing conditions and their relationship with the structure composite or nano-composites or in general multiphase polymeric materials with special properties induced by processing

Published Papers (6 papers)

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Research

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Open AccessArticle
Evaluation of a Novel Nanodroplet Cutting Fluid for Diamond Turning of Optical Polymers
Polymers 2020, 12(10), 2213; https://doi.org/10.3390/polym12102213 - 27 Sep 2020
Abstract
In this study, a novel nanodroplet cutting fluid (NDCF), consisting of emulsified water and oil nanodroplets, was developed to improve the surface quality of the single-point diamond-turned optical polymers. This developed NDCF was able to penetrate the chip–tool interface, contributing to both cooling [...] Read more.
In this study, a novel nanodroplet cutting fluid (NDCF), consisting of emulsified water and oil nanodroplets, was developed to improve the surface quality of the single-point diamond-turned optical polymers. This developed NDCF was able to penetrate the chip–tool interface, contributing to both cooling and lubricating effects. The performance of NDCF was evaluated from perspectives of the surface irregularity, roughness, and cutting force of the machined groove in a series of taper cutting experiments. Meanwhile, a high-quality optical surface was obtained and the micro-level form error was reduced in the diamond turning of a Polymethylmethacrylate (PMMA) microlens array. Full article
(This article belongs to the Special Issue Processing-Structure-Properties Relationships in Polymers II)
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Open AccessArticle
Physical and Morphological Properties of Tough and Transparent PMMA-Based Blends Modified with Polyrotaxane
Polymers 2020, 12(8), 1790; https://doi.org/10.3390/polym12081790 - 10 Aug 2020
Abstract
We prepared several novel, tough, and transparent poly(methyl methacrylate) (PMMA) blends modified with polyrotaxane (PR) and evaluated their physical properties and morphologies. A styrene/methyl methacrylate/maleic anhydride (SMM) copolymer that was miscible with PMMA was used as a reactive compatibilizer to enhance interfacial adhesion [...] Read more.
We prepared several novel, tough, and transparent poly(methyl methacrylate) (PMMA) blends modified with polyrotaxane (PR) and evaluated their physical properties and morphologies. A styrene/methyl methacrylate/maleic anhydride (SMM) copolymer that was miscible with PMMA was used as a reactive compatibilizer to enhance interfacial adhesion between the matrix resin and PR. A twin-screw melt-kneading extruder was used to prepare the polymer blends, and their thermal, morphological, optical, and mechanical properties were characterized. The effect of PR was evaluated by analyzing the deformation behavior of the blends in notched three-point bending tests. A PMMA/PR blend was immiscible and appeared to be a phase-separated system. However, when SMM was added as a compatibilizer, PR was partially miscible and did not form observable PR domains. Viscosity increased, and the glass transition temperature (Tg) of the matrix resin decreased. The surface hardness of a PMMA/SMM/PR blend was only 15% lower than that of PMMA. A 2.5-fold increase in elongation at breakage was observed, and the tensile strength and Young’s modulus decreased by 16%. The PMMA/SMM/PR blend had 60% higher impact strength than PMMA in notched Charpy impact test, which indicated that the balance between stiffness and ductility was excellent. PR served as a starting point for plastic deformation in the PMMA/SMM/PR blend. We found that PR could initiate void and craze formation, even when it was finely dispersed at the nanoscale. The stress-relieving effect of PR was effective when it was tightly bound at the interfaces. The materials obtained in this study are expected to make a significant contribution to reducing the weight of the products by applying them as a replacement for glass. Full article
(This article belongs to the Special Issue Processing-Structure-Properties Relationships in Polymers II)
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Open AccessArticle
Systematic Investigation on the Structure-Property Relationship in Isotactic Polypropylene Films Processed via Cast Film Extrusion
Polymers 2020, 12(8), 1636; https://doi.org/10.3390/polym12081636 - 23 Jul 2020
Abstract
The effect of cast film extrusion processing conditions, such as the chill-roll temperature, temperature of the melt, and line speed, on the structure of different isotactic polypropylene homo- and random copolymers has been investigated by means of Small- and Wide-Angle X-ray Scattering (SAXS [...] Read more.
The effect of cast film extrusion processing conditions, such as the chill-roll temperature, temperature of the melt, and line speed, on the structure of different isotactic polypropylene homo- and random copolymers has been investigated by means of Small- and Wide-Angle X-ray Scattering (SAXS and WAXS) and correlated to stiffness and haze. Stiffness and transparency have been found to be strongly dependent on the temperature of the chill-roll. Interestingly, line speed has been found to affect the total crystallinity when the chill-roll temperature is increased, while an overall minor effect of the melt temperature was found for all cast films. The polymer characteristics, defined by the catalyst nature and comonomer content, affect the final material performance, with the single-site catalyzed grades performing better in both mechanics and optics. Haze levels were found to correlate with the mesophase content rather than to α-crystallinity and to be dependent on the domain size for all grades. The remarkably low haze levels reached by the single-site grade with higher isotacticity can arise from high nucleation rate and orientational effects, which ultimately yield smaller and smoother scattering domains. Full article
(This article belongs to the Special Issue Processing-Structure-Properties Relationships in Polymers II)
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Open AccessArticle
Development of Polypropylene-Based Single-Polymer Composites With Blends of Amorphous Poly-Alpha-Olefin and Random Polypropylene Copolymer
Polymers 2020, 12(6), 1429; https://doi.org/10.3390/polym12061429 - 26 Jun 2020
Abstract
We developed polypropylene-based single-polymer composites (PP-SPC) with blends of amorphous poly-alpha-olefin (APAO) and random polypropylene copolymer (rPP) as matrix material and polypropylene (PP) woven fabric as reinforcement. Our goal was to utilize the lower melting temperature of APAO/rPP blends to increase the consolidation [...] Read more.
We developed polypropylene-based single-polymer composites (PP-SPC) with blends of amorphous poly-alpha-olefin (APAO) and random polypropylene copolymer (rPP) as matrix material and polypropylene (PP) woven fabric as reinforcement. Our goal was to utilize the lower melting temperature of APAO/rPP blends to increase the consolidation of the composites and decrease the heat load of the PP reinforcement. We produced the composites by film-stacking at 160 °C, and characterized the composites with density, peel, static tensile and dynamic falling weight impact tests, and by scanning electron microscopy. The results indicate that consolidation can be enhanced by increasing the APAO content of the matrix. We found that the APAO content of 50% is optimal for tensile properties. With increasing APAO content, the perforation energy decreased, but even the well-consolidated composites showed very high perforation energy. In the case of a pure APAO matrix, fiber content can be increased up to 80 wt% without a severe loss of consolidation, resulting in good tensile properties. The PP-SPCs developed possessed excellent mechanical properties, and well-consolidated composites can be produced with APAO/rPP blends as a matrix with high fiber content. Full article
(This article belongs to the Special Issue Processing-Structure-Properties Relationships in Polymers II)
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Open AccessArticle
Influence of Different Types of Peroxides on the Long-Chain Branching of PP via Reactive Extrusion
Polymers 2020, 12(4), 886; https://doi.org/10.3390/polym12040886 - 11 Apr 2020
Cited by 2
Abstract
Long-chain branching (LCB) is known as a suitable method to increase the melt strength behavior of linear polypropylene (PP), which is a fundamental weakness of this material. This enables the modification of various properties of PP, which can then be used—in the case [...] Read more.
Long-chain branching (LCB) is known as a suitable method to increase the melt strength behavior of linear polypropylene (PP), which is a fundamental weakness of this material. This enables the modification of various properties of PP, which can then be used—in the case of PP recyclates—as a practical “upcycling” method. In this study, the effect of five different peroxides and their effectiveness in building LCB as well as the obtained mechanical properties were studied. A single screw extruder at different temperatures (180 and 240 °C) was used, and long-chain branched polypropylene (PP-LCB) was prepared via reactive extrusion by directly mixing the peroxides. The peroxides used were dimyristyl peroxydicarbonate (PODIC C126), tert-butylperoxy isopropylcarbonate (BIC), tert-Butylperoxy 2-ethylhexyl carbonate (BEC), tert-amylperoxy 2-ethylhexylcarbonate (AEC), and dilauroyl peroxide (LP), all with a concentration of 20 mmol/kg. The influence of the temperature on the competitive prevalent reactions of degradation and branching was documented via melt mass-flow rate (MFR), rheology measurements, and gel permeation chromatography (GPC). However, via extensional rheology, strain hardening could be observed in all cases and the mechanical properties could be maintained or even improved. Particularly, PODIC C126 and LP signaled a promising possibility for LCB in this study. Full article
(This article belongs to the Special Issue Processing-Structure-Properties Relationships in Polymers II)
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Review

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Open AccessReview
Antiplasticization of Polymer Materials: Structural Aspects and Effects on Mechanical and Diffusion-Controlled Properties
Polymers 2020, 12(4), 769; https://doi.org/10.3390/polym12040769 - 01 Apr 2020
Abstract
Antiplasticization of glassy polymers, arising from the addition of small amounts of plasticizer, was examined to highlight the developments that have taken place over the last few decades, aiming to fill gaps of knowledge in the large number of disjointed publications. The analysis [...] Read more.
Antiplasticization of glassy polymers, arising from the addition of small amounts of plasticizer, was examined to highlight the developments that have taken place over the last few decades, aiming to fill gaps of knowledge in the large number of disjointed publications. The analysis includes the role of polymer/plasticizer molecular interactions and the conditions leading to the cross-over from antiplasticization to plasticization. This was based on molecular dynamics considerations of thermal transitions and related relaxation spectra, alongside the deviation of free volumes from the additivity rule. Useful insights were gained from an analysis of data on molecular glasses, including the implications of the glass fragility concept. The effects of molecular packing resulting from antiplasticization are also discussed in the context of physical ageing. These include considerations on the effects on mechanical properties and diffusion-controlled behaviour. Some peculiar features of antiplasticization regarding changes in Tg were probed and the effects of water were examined, both as a single component and in combination with other plasticizers to illustrate the role of intermolecular forces. The analysis has also brought to light the shortcomings of existing theories for disregarding the dual cross-over from antiplasticization to plasticization with respect to modulus variation with temperature and for not addressing failure related properties, such as yielding, crazing and fracture toughness. Full article
(This article belongs to the Special Issue Processing-Structure-Properties Relationships in Polymers II)
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