Polymer Science, Technology and Engineering beyond 2020: Novel, Safer and Sustainable Materials

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

Deadline for manuscript submissions: closed (5 April 2023) | Viewed by 19245

Special Issue Editors

Institute of Sustainable Industries and Liveable Cities, Victoria University, P.O. Box 14428, Melbourne, VIC 8001, Australia
Interests: polymer synthesis; environmentally sustainable flame retardant materials; cellulosic combustion and bush fires; waste recycling/management; adaptation of the existing processes/strategies towards more effective means of combustion
Special Issues, Collections and Topics in MDPI journals
Belfast School of Architecture and the Built Environment, Ulster University, Newtownabbey BT37 0QB, Northern Ireland, UK
Interests: chain-growth polymers; combustion; thermal decomposition; flammability; fire retardants; ligno-cellulosic materials; waste recycling and management; sustainability
Special Issues, Collections and Topics in MDPI journals
Institute of Sustainable Industries and Liveable Cities, Victoria University, P.O. Box 14428, Melbourne, VIC 8001, Australia
Interests: polymer processing; polymer engineering; polymer syntheses and characterisation; functional materials; combustion chemistry
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

We are currently going through unprecedented times, with an ongoing pandemic at a scale that has not been seen since the Spanish flu about 100 years ago. Within the same period, we have also witnessed great scientific and practical strides in the realm of polymeric materials, and an ensuing era of synthetic commodity plastics and associated materials for high-tech engineering applications. Concomitantly, we have become acutely aware of the problem that has unfolded owing to an enhanced use of these materials in our everyday life. The predominance of stronger covalent linkages between the prominent elements constituting the macromolecules render them significantly resistant  to natural degradation, and this has led to the  mammoth task of deposal of the polymer-based products upon reaching the end of their service life. Naturally, the attention of the scientific community has turned, especially in the last 10 years or so, towards preparing and formulating bio-degradable polymers and hybrid materials that are derived from bio-inspired sources.

It is highly likely that any post-COVID economic recovery will entail fast-paced construction, including both residential homes and infrastructural provisions, as well as fuel-efficient and more integrated transportation networks. Needless to say, we need to expend a more concerted effort in designing and developing  novel, safer, and sustainable materials. This would reduce our dependency on fossil-fuel-derived materials and technologies, and at the same time uphold the principle of  the much-needed circular economy. Ideally, we should rely more on materials that can be sourced from the natural world and/or devise methods to fabricate hybrid materials that incorporate them as a major component. The current Special Issue will therefore focus on concepts, synthetic methodologies, characterization techniques, and engineering aspects of polymeric materials that help to serve the underpinning ethos of novelty, safety, and sustainability beyond 2020. Through this Issue, we invite original papers and review  articles, primarily in the following categories and cognate subject areas:

  1. Theoretical basis and validation of the performance of hybrid polymeric materials;
  2. Novel synthetic strategies and formulation techniques pertaining to sustainable materials;
  3. Morphological and structural characteristics of  modern materials;
  4. Physical and performance evaluations of materials;
  5. Bio-degradable polymers;
  6. Bio-sourced components for hybrid materials;
  7. Recycling/reuse and life-cycle analyses of materials in the construction and transport sectors;
  8. Stimuli-responsive and three-dimensional networks;
  9. Sustainable polymeric materials beyond 2020;
  10. Modern materials in the context of circular economy.

Prof. Dr. Paul Joseph
Dr. Svetlana Tretsiakova-McNally
Dr. Malavika Arun
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 submissions that pass pre-check are 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 semimonthly 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 2700 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.

Published Papers (7 papers)

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Research

8 pages, 2458 KiB  
Article
Separating Information on Transparent Polypropylene Labels on Packaging with Dual Properties for the Visible Spectrum and Instrumental Infrared Observation
by Denis Jurečić, Jana Žiljak Gršić, Diana Bratić and Silvio Plehati
Polymers 2022, 14(24), 5341; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14245341 - 07 Dec 2022
Cited by 1 | Viewed by 1260
Abstract
Transparent linear NIR digital graphics with the intention of security information were printed on a polypropylene material. A label for expensive juices in transparent glass or plastic packaging is demonstrated. Obligatory information about the contents of the liquid was made to be read [...] Read more.
Transparent linear NIR digital graphics with the intention of security information were printed on a polypropylene material. A label for expensive juices in transparent glass or plastic packaging is demonstrated. Obligatory information about the contents of the liquid was made to be read with the naked eye. The “Z” (near-infrared) information is expanded with data integrated for joint digital printing. This data does not disrupt the original, planned visual appearance of the label, “V” (visible). Although the two graphics are in the same place, the IR graphics on the label cannot be discerned with the naked eye. This brings elements of secrecy and protection against attempts to counterfeit the contents of the transparent packaging. The separation and recognition of the two pieces of information, V and Z, are achieved with a security camera in the near-infrared mode or with one of the many NIR detectors that surround us. In the article, the “VZ” algorithm for the integration of two independent graphics and the limitations set by digital printing are published. Toner properties and the method for developing the recipes for the composition of twin colorants for two spectral ranges are presented using spectroscopy. Full article
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14 pages, 3325 KiB  
Article
Mechanochemistry: An Efficient Way to Recycle Thermoset Polyurethanes
by Ping He, Hao Lu, Haoda Ruan, Congyang Wang, Qiang Zhang, Zezhong Huang and Jing Liu
Polymers 2022, 14(16), 3277; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14163277 - 11 Aug 2022
Cited by 10 | Viewed by 2209
Abstract
A recycling process of waste thermosetting polyurethane plastics was proposed based on the mechanochemical method, aiming at the three-dimensional network cross-linking structure of thermosetting polyurethane. Orthogonal experimental design was adopted to select three factors of crushing speed, crushing time, and feed amount to [...] Read more.
A recycling process of waste thermosetting polyurethane plastics was proposed based on the mechanochemical method, aiming at the three-dimensional network cross-linking structure of thermosetting polyurethane. Orthogonal experimental design was adopted to select three factors of crushing speed, crushing time, and feed amount to determine the best crushing parameters. Then, the waste polyurethane insulation boards were crushed and degraded by the mechanism of regenerative forming with the adjustable speed test machine. Accordingly, the recycled powder was obtained. Finally, nine kinds of polyurethane recycled composite plates were prepared by hot pressing process. The degradation effect of thermosetting polyurethane was analyzed by Fourier transform infrared spectroscopy, scanning electron microscope, and X-ray diffraction. Moreover, the mechanical properties and thermal insulation properties of recycled composite plates were tested and analyzed. The results show that the network cross-linking molecular structure of waste thermosetting polyurethane plastics is destroyed by the effect of mechanochemical action, and methyl and aldehyde groups are decomposed. Therefore, a recycled powder with strong reactivity and plasticity is generated, which improves the activity regeneration ability. After adding thermoplastic resin, the mechanical properties and formability of recycled composite plates are enhanced, with maximum tensile strength up to 9.913 MPa. Correspondingly, the thermal insulation performance of plates is reduced. However, the minimum thermal conductivity can also reach 0.056 W/m·K. This study provides an effective method for the recycling of thermosetting polyurethane plastics. Full article
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16 pages, 5267 KiB  
Article
Thermal and Calorimetric Investigations of Some Phosphorus-Modified Chain Growth Polymers 1: Polymethyl Methacrylate
by Malavika Arun, Stephen Bigger, Maurice Guerrieri, Paul Joseph and Svetlana Tretsiakova-McNally
Polymers 2022, 14(7), 1447; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14071447 - 01 Apr 2022
Cited by 1 | Viewed by 1903
Abstract
The thermal and calorimetric characterizations of polymethyl methacrylate-based polymers are reported in this paper. The modifying groups incorporated the phosphorus atom in various chemical environments, including oxidation states of III, or V. Both additive and reactive strategies were employed, where the loading of [...] Read more.
The thermal and calorimetric characterizations of polymethyl methacrylate-based polymers are reported in this paper. The modifying groups incorporated the phosphorus atom in various chemical environments, including oxidation states of III, or V. Both additive and reactive strategies were employed, where the loading of phosphorus was kept at 2 wt% in all cases. The plaques, obtained through the bulk polymerization route, were subjected to a variety of spectroscopic, thermal and combustion techniques. The results showed that the different modifying groups exerted varying nature, degrees and modes of combustion behaviors, which also included in some cases an additive, and even an antagonistic effect. In the case of covalently-bound phosphonate groups, early cracking of the pendent ester moieties was shown to produce phosphoric acid species, which in turn can act in the condensed phase. For the additives, such as phosphine and phosphine oxide, limited vapor-phase inhibition can be assumed to be operative. Full article
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12 pages, 2493 KiB  
Article
Passive Fire Protection of Taeda pine Wood by Using Starch-Based Surface Coatings
by Svetlana Tretsiakova-McNally, Adeline Le Douarin, Paul Joseph and Malavika Arun
Polymers 2021, 13(21), 3841; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13213841 - 06 Nov 2021
Cited by 2 | Viewed by 1929
Abstract
The present paper reports the preliminary results relating to the development, subsequent application, and testing of environmentally benign starch-based formulations for passive fire protection of wood substrates. This study evaluated the effectiveness of starch colloid coatings applied onto the wood surface with a [...] Read more.
The present paper reports the preliminary results relating to the development, subsequent application, and testing of environmentally benign starch-based formulations for passive fire protection of wood substrates. This study evaluated the effectiveness of starch colloid coatings applied onto the wood surface with a view to improving its performance when exposed to the external heat flux (35 kW/m2) during cone calorimetric tests. The formulations were prepared from aqueous colloid solutions of either starch alone, or in combination with inorganic salts, such as: sodium carbonate, Na2CO3, potassium carbonate, K2CO3, and diammonium hydrogen phosphate, (NH4)2HPO4. The fire performance of Taeda pine wood samples, where their top surfaces were treated with these formulations, was compared with the control sample. The thermal and combustion characteristics of the tested samples were determined with the aid of thermo-gravimetric analysis (TGA), bomb and cone calorimetric techniques, and a steady state tube furnace coupled to an FT-IR spectrometer. A significant boost of fire protection was observed when starch formulations with added inorganic salts were applied onto the wood surfaces, compared with the control sample. For example, the presence of K2CO3 in starch colloid solutions resulted in a notable delay of the ignition and exhibited a reduction in the heat release parameters in comparison with the untreated wood substrate. Full article
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21 pages, 5583 KiB  
Article
Production of Rigid Polyurethane Foams Using Polyol from Liquefied Oil Palm Biomass: Variation of Isocyanate Indexes
by Umar Adli Amran, Kushairi Mohd Salleh, Sarani Zakaria, Rasidi Roslan, Chin Hua Chia, Sharifah Nabihah Syed Jaafar, Mohd Shaiful Sajab and Marhaini Mostapha
Polymers 2021, 13(18), 3072; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13183072 - 11 Sep 2021
Cited by 16 | Viewed by 3008
Abstract
Development of polyurethane foam (PUF) containing bio-based components is a complex process that requires extensive studies. This work reports on the production of rigid PUFs from polyol obtained via liquefaction of oil palm empty fruit bunch (EFB) biomass with different isocyanate (NCO) indexes. [...] Read more.
Development of polyurethane foam (PUF) containing bio-based components is a complex process that requires extensive studies. This work reports on the production of rigid PUFs from polyol obtained via liquefaction of oil palm empty fruit bunch (EFB) biomass with different isocyanate (NCO) indexes. The effect of the NCO index on the physical, chemical and compressive properties of the liquefied EFB-based PUF (EFBPUF) was evaluated. The EFBPUFs showed a unique set of properties at each NCO index. Foaming properties had affected the apparent density and cellular morphology of the EFBPUFs. Increasing NCO index had increased the crosslink density and dimensional stability of the EFBPUFs via formation of isocyanurates, which had also increased their thermal stability. Combination of both foaming properties and crosslink density of the EFBPUFs had influenced their respective compressive properties. The EFBPUF produced at the NCO index of 120 showed the optimum compressive strength and released the least toxic hydrogen cyanide (HCN) gas under thermal degradation. The normalized compressive strength of the EFBPUF at the NCO index of 120 is also comparable with the strength of the PUF produced using petrochemical polyol. Full article
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21 pages, 40268 KiB  
Article
Influence of 3D-Printed TPU Properties for the Design of Elastic Products
by Lucía Rodríguez-Parada, Sergio de la Rosa and Pedro F. Mayuet
Polymers 2021, 13(15), 2519; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13152519 - 30 Jul 2021
Cited by 27 | Viewed by 4154
Abstract
The design of products with elastic properties is a paradigm for design engineers because the properties of the material define the correct functionality of the product. Fused filament fabrication (FFF) allows for the printing of products in thermoplastic polyurethanes (TPU). Therefore, it offers [...] Read more.
The design of products with elastic properties is a paradigm for design engineers because the properties of the material define the correct functionality of the product. Fused filament fabrication (FFF) allows for the printing of products in thermoplastic polyurethanes (TPU). Therefore, it offers the ability to design elastic products with the freedom of forms that this technology allows and also with greater variation of elastic properties than with a conventional process. The internal structures and the variation in thickness that can be used facilitate the design of products with different elastic realities, producing variations in the elasticity of the product with the same material. This work studies the influence of the variation of internal density as a function of basic geometries in order to quantify the difference in elasticity produced on a product when it is designed. Likewise, a case study was carried out with the creation of a fully elastic computer keyboard printed in 3D. The specimens were subjected to compression to characterize the behavior of the structures. The tests showed that the elasticity varies depending on the orientation and geometry, with the highest compressive strength observed in the vertical orientation with 80% lightening. In addition, the internal lightening increases the elasticity progressively but not uniformly with respect to the solid geometry, and also the flat faces favour the reduction in elasticity. This study classifies the behavior of TPU with the aim of being applied to the design and manufacture of products with specific properties. In this work, a totally flexible and functional keyboard was designed, obtaining elasticity values that validate the study carried out. Full article
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10 pages, 3016 KiB  
Article
Acetylation Modification of Waste Polystyrene and Its Use as a Crude Oil Flow Improver
by Wangyuan Zhang, Michal Slaný, Jie Zhang, Yifan Liu, Yunlei Zang, Yongfei Li and Gang Chen
Polymers 2021, 13(15), 2505; https://0-doi-org.brum.beds.ac.uk/10.3390/polym13152505 - 29 Jul 2021
Cited by 13 | Viewed by 3289
Abstract
Polystyrene is used in a wide range of applications in our lives, from machine housings to plastic cups and miniature electronic devices. When polystyrene is used, a large amount of waste is produced, which can cause pollution to the environment and even harm [...] Read more.
Polystyrene is used in a wide range of applications in our lives, from machine housings to plastic cups and miniature electronic devices. When polystyrene is used, a large amount of waste is produced, which can cause pollution to the environment and even harm biological and human health. Due to its low bulk density (especially the foamed type) and low residual value, polystyrene cannot be easily recycled. Often waste polystyrene is difficult to recycle. In this paper, waste polystyrene has been modified by using acetic anhydride which caused a crude oil flow improver. The results showed that modified polystyrene improves the flow properties of the crude oil, reducing the viscosity and the pour point of the crude oil by up to 84.6% and 8.8 °C, respectively. Based on the study of the paraffin crystal morphology, the mechanism of improving the flow capacity of crude oil by modified polystyrene was proposed and analyzed. Full article
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