Polymer Structure and Property III

A special issue of Polymers (ISSN 2073-4360).

Deadline for manuscript submissions: closed (30 November 2020) | Viewed by 23787

Special Issue Editors


E-Mail Website
Guest Editor
Department of Civil, Chemical, Environmental and Materials Engineering, University of Bologna, Via Terracini 28, 40131 Bologna, Italy
Interests: polymer synthesis; polymer modification; copolymerization; polymer characterization; solid state properties in polymers; polymer thermal properties; polymer crystallization kinetics; mechanical characterization; bio-based monomers; biopolymers; biomaterials; polymer nanostructuring; nanocomposites; gas barrier properties; polymer compostability; biopolymers for tissue engineering; polymeric devices for controlled drug delivery; biodegradation
Special Issues, Collections and Topics in MDPI journals

E-Mail Website
Guest Editor
Department of Civil, Chemical, Environmental and Materials Engineering, University of Bologna, 40126 Bologna, Italy
Interests: polymer design; polymer synthesis and characterization; polymer modification; copolymerization; solid state properties; thermal properties and crystallization kinetics; mechanical characterization; bio-based monomers; bio-based polymers; nano-polymer; nanocomposites; gas barrier behaviour; polymer compostability; biopolymers for engineering tissue; polymeric for controlled drug delivery; biodegradation
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

To build on the success of the Special Issues in Polymers on the topic of "Polymer Structure and Property” and to provide a continuity of this popular topic, we are pleased to open the third volume of this Special Issue.

Volume I and II are available at the following links:

https://www.mdpi.com/journal/polymers/special_issues/Struct_Prop,
https://www.mdpi.com/journal/polymers/special_issues/Struct_Prop_II.

The aim of this Special Issue is to collect original research and comprehensive review papers in order to understand the state of the art as well as to obtain insight into the possible correlations between the structure and the property of polymers. All relevant contributions to this Special Issue are welcome.

Related Special Issues

Published Papers (6 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

10 pages, 2689 KiB  
Article
Adhesion and Energy Characteristics of Rigid-Chain Polymer Surface: Polyamidoimides
by Anatoly E. Chalykh, Valentina Yu. Stepanenko and Ali D. Aliev
Polymers 2020, 12(12), 2956; https://doi.org/10.3390/polym12122956 - 10 Dec 2020
Cited by 4 | Viewed by 1847
Abstract
The adhesion characteristics and surface energies of two series of polyamidoimides (PAI) with different molecular weights, monomer unit structures, hinge groups in the main chain of the macromolecules, and thermal prehistory were determined via delamination at 180° and test fluids contact angles. We [...] Read more.
The adhesion characteristics and surface energies of two series of polyamidoimides (PAI) with different molecular weights, monomer unit structures, hinge groups in the main chain of the macromolecules, and thermal prehistory were determined via delamination at 180° and test fluids contact angles. We found that PAI are high-energy polymers, the surface energy of which varies in the range from 32 to 45 mJ/m2. In contrast to flexible-chain polymers, the exponent in the McLeod equation is two, which is due to the flat parallel orientation of the macromolecular chains in the surface layers. The main contribution to the change in surface characteristics of these polymers is the change in the packing density of PAI macromolecules, which is reflected mainly in the change in the polymers’ dispersion component. We found that the adhesion properties of PAI with respect to high- and low-energy substrates are determined mainly by the macromolecules packing density in the surface layers with their conformation state unchanged. Full article
(This article belongs to the Special Issue Polymer Structure and Property III)
Show Figures

Graphical abstract

20 pages, 2765 KiB  
Article
Effect of Different Compatibilization Systems on the Rheological, Mechanical and Morphological Properties of Polypropylene/Polystyrene Blends
by Martina Seier, Sascha Stanic, Thomas Koch and Vasiliki-Maria Archodoulaki
Polymers 2020, 12(10), 2335; https://doi.org/10.3390/polym12102335 - 13 Oct 2020
Cited by 14 | Viewed by 4926
Abstract
The influence of reactive processing, non reactive and reactive copolymers on immiscible polypropylene (PP)–polystyrene (PS) blends with varying PS concentrations (10 wt.% and 25 wt.%) was evaluated by mechanical (tensile and tensile impact), rheological (melt flow rate, extensional and dynamic rheology) and morphological [...] Read more.
The influence of reactive processing, non reactive and reactive copolymers on immiscible polypropylene (PP)–polystyrene (PS) blends with varying PS concentrations (10 wt.% and 25 wt.%) was evaluated by mechanical (tensile and tensile impact), rheological (melt flow rate, extensional and dynamic rheology) and morphological (scanning electron microscopy) analysis. As an extended framework of the study, the creation of a link to industrial applicable processing conditions as well as an economically efficient use of compatibilzing agent were considered. For radical processed blends, a high improvement in melt strength was observed while non reactive copolymers exhibited a pronounced increase in toughness and ductility correlated with overall best phase homogeneity. Conversely, the influence of the reactive copolymer was quite different for the varied PS concentrations not allowing the assumption of a specific trend for resulting blend properties, but nevertheless in the case of a lower PS concentration the tensile impact strength exceeded the value of virgin PP. Since PS and PP are widely used, the findings of this work could not only be relevant for the generation of more versatile blends compared to virgin components but also for recycling purposes, allowing the enhancement of specific properties facilitating the production of more valuable secondary materials. Full article
(This article belongs to the Special Issue Polymer Structure and Property III)
Show Figures

Figure 1

14 pages, 6024 KiB  
Article
Curing Behavior, Rheological, and Thermal Properties of DGEBA Modified with Synthesized BPA/PEG Hyperbranched Epoxy after Their Photo-Initiated Cationic Polymerization
by Tossapol Boonlert-uthai, Kentaro Taki and Anongnat Somwangthanaroj
Polymers 2020, 12(10), 2240; https://doi.org/10.3390/polym12102240 - 29 Sep 2020
Cited by 3 | Viewed by 3975
Abstract
This paper investigates the photo-initiated cationic polymerization of diglycidyl ether of bisphenol A (DGEBA) modified with bisphenol A (BPA)/polyethylene glycol (PEG) hyperbranched epoxy resin. The relationship between curing behavior, rheological, and thermal properties of the modified DGEBA is investigated using photo-differential scanning calorimetry [...] Read more.
This paper investigates the photo-initiated cationic polymerization of diglycidyl ether of bisphenol A (DGEBA) modified with bisphenol A (BPA)/polyethylene glycol (PEG) hyperbranched epoxy resin. The relationship between curing behavior, rheological, and thermal properties of the modified DGEBA is investigated using photo-differential scanning calorimetry (DSC) and photo-rheometer techniques. It is seen that the addition of the hyperbranched epoxy resin can increase UV conversion (αUV) and reduce gelation time (tgel). After photo-initiation polymerization (dark reaction) occurred, a second exothermic peak in the DSC thermogram takes place: namely, the occurrence of curing reaction owing to the activated monomer (AM) mechanism. Consequently, the glass transition temperature decreased, and at the same time, UV intensity increased which was due to the molecular weight between crosslinking points (Mc). Furthermore, the radius of gyration (Rg) of the network segment is determined via small-angle X-ray scattering (SAXS). It is noted that the higher the Mc, the larger the radius of gyration proves to be, resulting in low glass transition temperature. Full article
(This article belongs to the Special Issue Polymer Structure and Property III)
Show Figures

Graphical abstract

20 pages, 7615 KiB  
Article
Synthesis and Nonisothermal Crystallization Kinetics of Poly(Butylene Terephthalate-co-Tetramethylene Ether Glycol) Copolyesters
by Hsu-I Mao, Chin-Wen Chen and Syang-Peng Rwei
Polymers 2020, 12(9), 1897; https://doi.org/10.3390/polym12091897 - 24 Aug 2020
Cited by 12 | Viewed by 4803
Abstract
Poly(butylene terephthalate-co-tetramethylene ether glycol) (PBT-co-PTMEG) copolymers with PTMEG ranging from 0 to 40 wt% were synthesized through melt polymerization. The structure and composition were supported by Fourier-transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (1H NMR). [...] Read more.
Poly(butylene terephthalate-co-tetramethylene ether glycol) (PBT-co-PTMEG) copolymers with PTMEG ranging from 0 to 40 wt% were synthesized through melt polymerization. The structure and composition were supported by Fourier-transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (1H NMR). All samples had excellent thermal stability at a Td−5% around 370 °C. Crystallization temperature (Tc) and enthalpy of crystallization (ΔHc) were detected by differential scanning calorimetry (DSC), revealing a decrement from 182.3 to 135.1 °C and 47.0 to 22.1 J g−1, respectively, with the increase in PTMEG concentration from 0 to 40 wt%. Moreover, nonisothermal crystallization was carried out to explore the crystallization behavior of copolymers; the crystallization rate of PBT reduced gradually when PTMEG content increased. Hence, a decrement in the spherulite growth rate was detected in polarizing light microscope (PLM) observation, observing that the PTMEG could enhance the hindrance in the molecular chain to lower the crystallinity of PBT-co-PTMEG copolyester. Moreover, thermal properties and the crystallization rate of PBT-co-PTMEG copolymers can be amended via the regulation of PTMEG contents. Full article
(This article belongs to the Special Issue Polymer Structure and Property III)
Show Figures

Graphical abstract

14 pages, 2637 KiB  
Article
Seventeen-Armed Star Polystyrenes in Various Molecular Weights: Structural Details and Chain Characteristics
by Jia Chyi Wong, Li Xiang, Kuan Hoon Ngoi, Chin Hua Chia, Kyeong Sik Jin, Akira Hirao and Moonhor Ree
Polymers 2020, 12(9), 1894; https://doi.org/10.3390/polym12091894 - 23 Aug 2020
Cited by 3 | Viewed by 2265
Abstract
Star-shaped polymers are very attractive because of their potential application ability in various technological areas due to their unique molecular topology. Thus, information on the molecular structure and chain characteristics of star polymers is essential for gaining insights into their properties and finding [...] Read more.
Star-shaped polymers are very attractive because of their potential application ability in various technological areas due to their unique molecular topology. Thus, information on the molecular structure and chain characteristics of star polymers is essential for gaining insights into their properties and finding better applications. In this study, we report molecular structure details and chain characteristics of 17-armed polystyrenes in various molecular weights: 17-Arm(2k)-PS, 17-Arm(6k)-PS, 17-Arm(10k)-PS, and 17-Arm(20k)-PS. Quantitative X-ray scattering analysis using synchrotron radiation sources was conducted for this series of star polymers in two different solvents (cyclohexane and tetrahydrofuran), providing a comprehensive set of three-dimensional structure parameters, including radial density profiles and chain characteristics. Some of the structural parameters were crosschecked by qualitative scattering analysis and dynamic light scattering. They all were found to have ellipsoidal shapes consisting of a core and a fuzzy shell; such ellipse nature is originated from the dendritic core. In particular, the fraction of the fuzzy shell part enabling to store desired chemicals or agents was confirmed to be exceptionally high in cyclohexane, ranging from 74 to 81%; higher-molecular-weight star polymer gives a larger fraction of the fuzzy shell. The largest fraction (81%) of the fuzzy shell was significantly reduced to 52% in tetrahydrofuran; in contrast, the lowest fraction (19%) of core was increased to 48%. These selective shell contraction and core expansion can be useful as a key mechanism in various applications. Overall, the 17-armed polystyrenes of this study are suitable for applications in various technological fields including smart deliveries of drugs, genes, biomedical imaging agents, and other desired chemicals. Full article
(This article belongs to the Special Issue Polymer Structure and Property III)
Show Figures

Graphical abstract

18 pages, 3267 KiB  
Article
Effect of Mixing Method on Properties of Ethylene Vinyl Acetate Copolymer/Natural Rubber Thermoplastic Vulcanizates
by Nappaphan Kunanusont, Chavakorn Samthong, Fan Bowen, Masayuki Yamaguchi and Anongnat Somwangthanaroj
Polymers 2020, 12(8), 1739; https://doi.org/10.3390/polym12081739 - 4 Aug 2020
Cited by 12 | Viewed by 5406
Abstract
Thermoplastic vulcanizate (TPV) has excellent elastomeric properties and can be reprocessed multiple times. TPV is typically produced by using the dynamic vulcanization (DV) method in which rubber is crosslinked simultaneously with thermoplastics. Peroxide-crosslinked TPV can increase the compatibility between rubber and thermoplastics but [...] Read more.
Thermoplastic vulcanizate (TPV) has excellent elastomeric properties and can be reprocessed multiple times. TPV is typically produced by using the dynamic vulcanization (DV) method in which rubber is crosslinked simultaneously with thermoplastics. Peroxide-crosslinked TPV can increase the compatibility between rubber and thermoplastics but loses its reprocessability due to excess crosslinking in the latter. In this work, we overcome this obstacle by using a two-step mixing method to prepare fully crosslinked elastomers of ethylene vinyl acetate copolymer (EVA) and natural rubber (NR). Each sample formulation was prepared with three different mixing methods for comparison: NR-DV, Split-DV, and All-DV. For NR-DV, NR was crosslinked prior to the addition of EVA together with the thermal stabilizer (TS). For Split-DV, a small amount of EVA and NR was crosslinked prior to the addition of EVA and TS. In the All-DV method, EVA and NR were crosslinked, and then TS was added. The appearance and processability of the samples were affected by the degree of crosslinking. NR-DV showed a non-homogeneous texture. Although the samples of the All-DV method appeared homogeneous, their mechanical and rheological properties were inferior to those of the Split-DV method. The mechanical properties of the Split-DV samples were not significantly changed after reprocessing 10 times. Therefore, Split-DV is the preferred method for TPV production. Full article
(This article belongs to the Special Issue Polymer Structure and Property III)
Show Figures

Graphical abstract

Back to TopTop