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Polymer Blends and Compatibilization 2018
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Polymer Blends and Compatibilization 2018

A special issue of Materials (ISSN 1996-1944).

Deadline for manuscript submissions: closed (30 November 2018) | Viewed by 99109

Special Issue Editors

Prof. Dr. Francesco Paolo La Mantia

E-Mail Website1 Website2
Guest Editor
Department of Engineering, University of Palermo, RU INSTM, Viale delle Scienze, 90128 Palermo, Italy
Interests: polymer processing; mechanical behaviour of polymer-based systems; rheological behaviour of polymer-based systems; green composites; biocomposites; nanocomposites; biodegradable polymers; polymer blends; degradation and recycling of polymer-based systems
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Maria Chiara Mistretta

E-Mail Website
Guest Editor
Department of Engineering, University of Palermo, RU INSTM, Viale delle Scienze, 90128 Palermo, Italy
Interests: polymer blends; nanocomposites; degradation; recycling
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Polymer Blends are a class of multiphase polymer materials that present intermediary properties among their components. Blending of commercial polymers is the most efficient and cheap method to produce new polymeric materials that meet specific requirements. However, achieving the desired properties—mechanical strength, toughness, durability, etc—depends mainly on the final morphology achieved from the blends which, in turn, depends on the chemical nature and molecular structure of the macromolecules of the components. The different chemical nature of the components leads, in most cases, to bad morphology with voids, defects and a lack of adhesion between the phases and consequent poor properties. Moreover, the dispersed droplets can coalesce during processing, changing the morphology of the blends. The morphology must be “stabilized” in order to avoid any change during processing. An effective compatibilization technology is, then, a necessary step to obtain polymer blends with the desired properties. Compatibilization can be defined as the ability of the polymer components to coexist as distinct phases without macroscopic separation or delamination. Interfacial agents and reactive blending are common methods able to promote the stabilization of the morphology of the blends. This Special Issue intends to assess the state-of-the-art and the recent advances of this topic, evidencing the effect of compatibilization on the morphology and properties of the polymer blends.

It is my pleasure to invite you to submit a manuscript to this Special Issue on Polymer Blends and Compatibilization 2018. Full papers, communications, and reviews are all welcome.

Prof. Francesco La Mantia
Dr. Maria Chiara Mistretta
Guest Editors

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Keywords

  • Polymer Blends
  • Compatibilization
  • Interfacial Agents
  • Reactive Blending
  • Morphology

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Published Papers (17 papers)

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Research

18 pages, 17677 KiB  
Article
Reactive Compatibilization of PLA/PA11 Blends and Their Application in Additive Manufacturing
by Damien Rasselet, Anne-Sophie Caro-Bretelle, Aurélie Taguet and José-Marie Lopez-Cuesta
Materials 2019, 12(3), 485; https://doi.org/10.3390/ma12030485 - 5 Feb 2019
Cited by 63 | Viewed by 5817
Abstract
The aim of this work was to study the properties of polylatic acid/polyamide 11 (PLA/PA11) blends compatibilized with a multifunctionalized epoxide, Joncryl®, and to evaluate the performance of such blends processed by Fused Deposition Modeling (FDM) 3D printing, compared to those [...] Read more.
The aim of this work was to study the properties of polylatic acid/polyamide 11 (PLA/PA11) blends compatibilized with a multifunctionalized epoxide, Joncryl®, and to evaluate the performance of such blends processed by Fused Deposition Modeling (FDM) 3D printing, compared to those produced by injection molding method. Blends containing different Joncryl contents from 0.5 to 3 wt% were prepared by twin-screw extrusion. Evaluation of thermal, rheological and mechanical properties of such blends proved that Joncryl acted as a compatibilizer. Results showed that Joncryl effects on blends properties were improved with increasing its content. A significant reduction of PA11 dispersed phases diameter and an improvement of tensile properties with a ductile behavior were achieved for the highest Joncryl contents. A significant elongation of PA11 dispersed phases was observed into FDM filaments and dog bone shaped specimens produced thereafter. Despite this peculiar morphology, FDM printed samples exhibited only enhanced stiffness but poor reinforcement and elongation at break in comparison with injected ones. Full article
(This article belongs to the Special Issue Polymer Blends and Compatibilization 2018)
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20 pages, 7381 KiB  
Article
Improved Impact Properties in Poly(lactic acid) (PLA) Blends Containing Cellulose Acetate (CA) Prepared by Reactive Extrusion
by Maria-Beatrice Coltelli, Norma Mallegni, Sara Rizzo, Patrizia Cinelli and Andrea Lazzeri
Materials 2019, 12(2), 270; https://doi.org/10.3390/ma12020270 - 15 Jan 2019
Cited by 23 | Viewed by 4832
Abstract
Poly(lactic acid)/triacetine plasticized cellulose acetate (PLA/pCA) blends were prepared by extrusion at two different temperatures and tetrabutylammonium tetraphenyl borate (TBATPB) was added as a transesterification catalyst to reactively promote the formation of PLA-CA copolymer during the reactive extrusion. The occurrence of chain scission [...] Read more.
Poly(lactic acid)/triacetine plasticized cellulose acetate (PLA/pCA) blends were prepared by extrusion at two different temperatures and tetrabutylammonium tetraphenyl borate (TBATPB) was added as a transesterification catalyst to reactively promote the formation of PLA-CA copolymer during the reactive extrusion. The occurrence of chain scission in the PLA phase and branching/crosslinking in the CA phase in the presence of TBATPB, resulting also in a darkening of the material, were demonstrated by studying torque measurements and by performing proper thermogravimetric tests on CA with the different additives. Tensile and impact tests onto the blends prepared at the lower temperature showed better properties than the ones obtained at a higher temperature. Then, the mechanical properties of PLA/plasticized cellulose acetate (pCA) blends prepared at the lower temperature were investigated as a function of the content of plasticized CA in the blend. A range of compositions was observed where blends exhibited improved impact properties with respect to pure PLA without a significant decrease in their elastic modulus. The study of the phase morphology of the blends revealed that the occurrence of reactive compatibilization did not significantly affect the phase distribution. In general, fibrillar CA particles were formed in the PLA matrix during extrusion, thus allowing the preparation of CA fibre reinforced composites. The trend of morphology as a function of the composition and processing conditions was then discussed by considering the evolution of phase morphology in immiscible polymer blends. Full article
(This article belongs to the Special Issue Polymer Blends and Compatibilization 2018)
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13 pages, 10391 KiB  
Article
Compatibilization of Polypropylene/Polyamide 6 Blend Fibers Using Photo-Oxidized Polypropylene
by Francesco Paolo La Mantia, Manuela Ceraulo, Maria Chiara Mistretta, Luigi Botta and Marco Morreale
Materials 2019, 12(1), 81; https://doi.org/10.3390/ma12010081 - 27 Dec 2018
Cited by 12 | Viewed by 3780
Abstract
The use of polyamide/polyolefin blends has gained importance and concern for years, but they also show some issues to be adequately addressed, such as the incompatibility between the two components. This is usually overcome by using suitable compatibilizers, typically based on functionalized polyolefins. [...] Read more.
The use of polyamide/polyolefin blends has gained importance and concern for years, but they also show some issues to be adequately addressed, such as the incompatibility between the two components. This is usually overcome by using suitable compatibilizers, typically based on functionalized polyolefins. However, there is only little information about the use of a degraded polyolefins to induce compatibilization. This is even truer, as far as polyamide 6/polypropylene (PA6/PP) blends are concerned. In this work, compatibilization of PA6/PP blends by using small amounts of photo-oxidized PP was investigated; furthermore, the effects due to the presence of the photo-oxidized PP were studied also in relationship to the spinning operation, where the existence of the non-isothermal elongational flow can lead to significant, further morphological changes. It was found that isotropic samples showed significant enhancements of the tensile properties upon adding the photo-oxidized PP. Under non-isothermal elongational flow conditions, the presence of the photo-oxidized PP was particularly effective in improving the mechanical properties in comparison to the uncompatibilized blend fibers. Furthermore, an important result was found: The elongational-flow processing allowed obtaining anisotropic samples where the improvements of the properties, in comparison to the isotropic samples, were similar to those achieved by using a compatibilizer. Full article
(This article belongs to the Special Issue Polymer Blends and Compatibilization 2018)
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14 pages, 3443 KiB  
Article
The Effect of Different Compatibilizers on the Properties of a Post-Industrial PC/PET Blend
by Eleonora Dal Lago, Carlo Boaretti, Francesca Piovesan, Martina Roso, Alessandra Lorenzetti and Michele Modesti
Materials 2019, 12(1), 49; https://doi.org/10.3390/ma12010049 - 24 Dec 2018
Cited by 22 | Viewed by 5183
Abstract
The substitution of virgin resins by recycled ones is a worldwide tendency that is supported by the fluctuation of oil prices and the transition to a circular economy. Polymeric blends have been intensively studied because of their ability to provide tailored properties for [...] Read more.
The substitution of virgin resins by recycled ones is a worldwide tendency that is supported by the fluctuation of oil prices and the transition to a circular economy. Polymeric blends have been intensively studied because of their ability to provide tailored properties for particular applications. However, in their design phases, the issue of end-life re-use had not been well addressed, and now difficulties in their recycling are arising. In this study, we investigated the effect of three different compatibilizers: two chain extenders (CEs), (1) a styrene-acrylic oligomer (ESAo), and (2) methylene diphenyl diisocyanate (MDI) and an impact strength modifier, (3) an ethylene copolymer (EMAco), for the recycle of a post-industrial polycarbonate/polyethylene terephthalate (PC/PET) blend. The materials were prepared by reactive extrusion and characterized by intrinsic viscosity (IV) measurements, mechanical tests, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy analysis (FTIR), and transmission electron microscopy (TEM). The introduction of each additive has been demonstrated to improve the compatibility between PET and PC in the post-industrial blend, leading to enhanced mechanical properties. The IV measurements increased to values that were comparable to the virgin material. In addition, CEs affected the crystallization of PET (as they reduced the degree of crystallinity), while EMAco acted as a nucleating agent. Morphological analysis enabled confirming the compatibilization effects induced by the tested additives. Full article
(This article belongs to the Special Issue Polymer Blends and Compatibilization 2018)
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10 pages, 3578 KiB  
Article
Optimization of Thermoplastic Blend Matrix HDPE/PLA with Different Types and Levels of Coupling Agents
by Alessia Quitadamo, Valérie Massardier, Carlo Santulli and Marco Valente
Materials 2018, 11(12), 2527; https://doi.org/10.3390/ma11122527 - 12 Dec 2018
Cited by 23 | Viewed by 5003
Abstract
High-density polyethylene (HDPE) and poly(lactic) acid (PLA) blends with different ratios of both polymers, namely, 30:70, 50:50, and 70:30, were produced. Polyethylene-grafted maleic anhydride and a random copolymer of ethylene and glycidyl methacrylate were also considered as compatibilizers to modify HDPE/PLA optimal blends [...] Read more.
High-density polyethylene (HDPE) and poly(lactic) acid (PLA) blends with different ratios of both polymers, namely, 30:70, 50:50, and 70:30, were produced. Polyethylene-grafted maleic anhydride and a random copolymer of ethylene and glycidyl methacrylate were also considered as compatibilizers to modify HDPE/PLA optimal blends and were added in the amounts of 1, 3, and 5 wt.%. Different properties of the blends were evaluated by performing tensile tests and scanning electron microscopy to analyze blend and interfaces morphology. Moreover, thermomechanical analysis through differential scanning calorimetry, thermo-gravimetric analysis, and infrared spectroscopy were also performed. The blend containing equal amounts of HDPE and PLA seemed to present a good balance between amount of bio-derived charge and acceptable mechanical properties. This suggests that these blends have a good potential for the production of composites with lingo-cellulosic fillers. Full article
(This article belongs to the Special Issue Polymer Blends and Compatibilization 2018)
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10 pages, 2089 KiB  
Article
A Combined Approach of Double Network Hydrogel and Nanocomposites Based on Hyaluronic Acid and Poly(ethylene glycol) Diacrylate Blend
by Alfredo Ronca, Ugo D’Amora, Maria Grazia Raucci, Hai Lin, Yujiang Fan, Xingdong Zhang and Luigi Ambrosio
Materials 2018, 11(12), 2454; https://doi.org/10.3390/ma11122454 - 4 Dec 2018
Cited by 34 | Viewed by 5449
Abstract
In this study, an innovative polymer blend, based on double network (DN) approach, has been developed by integrating a poly(ethylene glycol) diacrylate (PEGDA) network into a chemically modified hyaluronic acid sodium salt (HAs) hydrogel matrix. Here, the HAs was chemically functionalized with photocrosslinkable [...] Read more.
In this study, an innovative polymer blend, based on double network (DN) approach, has been developed by integrating a poly(ethylene glycol) diacrylate (PEGDA) network into a chemically modified hyaluronic acid sodium salt (HAs) hydrogel matrix. Here, the HAs was chemically functionalized with photocrosslinkable moieties by reacting with maleic anhydride (MAA) to obtain a maleated hyaluronic acid (MaHA). Furthermore, nanocomposite DN hydrogels were suitably prepared by physical blending of hydroxyapatite nanoparticles (HAp), obtained by sol-gel synthesis, within the hydrogel. Physico-chemical, thermal, morphological and mechanical analyses were performed. Results showed enhanced mechanical properties and a homogenous microstructure as highlighted by mechanical and morphological investigations. This suggests that nanocomposite DN hydrogels are promising candidates for biomedical applications. Full article
(This article belongs to the Special Issue Polymer Blends and Compatibilization 2018)
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17 pages, 4658 KiB  
Article
Rheology–Microstructure Relationships in Melt-Processed Polylactide/Poly(vinylidene Fluoride) Blends
by Reza Salehiyan, Suprakas Sinha Ray, Florian J. Stadler and Vincent Ojijo
Materials 2018, 11(12), 2450; https://doi.org/10.3390/ma11122450 - 3 Dec 2018
Cited by 17 | Viewed by 5034
Abstract
In this study, small amplitude oscillatory shear tests are applied to investigate the rheological responses of polylactide/poly(vinylidene fluoride) (PLA/PVDF) blends and to correlate their viscoelastic properties with the morphological evolutions during processing. Although the analysis of the elastic moduli reveals some changes as [...] Read more.
In this study, small amplitude oscillatory shear tests are applied to investigate the rheological responses of polylactide/poly(vinylidene fluoride) (PLA/PVDF) blends and to correlate their viscoelastic properties with the morphological evolutions during processing. Although the analysis of the elastic moduli reveals some changes as a function of blend composition and processing time, the weighted relaxation spectra are shown to be more useful in detecting changes. The analysis demonstrates that when PVDF, i.e., the more viscous phase, is the matrix, the blend relaxes cooperatively and only a single relaxation peak is observed. By contrast, blends with highly concentrated morphologies do not fully relax, showing instead an upward increasing trend at longer times. This outcome is attributed to the broad distribution of highly concentrated droplets with a high probability of droplet–droplet contacts. Dynamic mechanical analysis (DMA) reveals that crystalline segmental motions attributed to the α-relaxation of PVDF at around 100 °C are restricted by the highly concentrated morphology of the 50/50 PLA/PVDF blend processed for 10 min. Relaxation analyses of the blends via dynamic oscillatory shear tests and DMA are shown to be powerful tools for investigating small microstructural changes in immiscible polymer blends. Full article
(This article belongs to the Special Issue Polymer Blends and Compatibilization 2018)
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10 pages, 2805 KiB  
Article
“Compatibilization” through Elongational Flow Processing of LDPE/PA6 Blends
by Maria Chiara Mistretta, Marco Morreale, Luigi Botta, Manuela Ceraulo, Paolo Fontana and Francesco Paolo La Mantia
Materials 2018, 11(12), 2375; https://doi.org/10.3390/ma11122375 - 26 Nov 2018
Cited by 9 | Viewed by 2932
Abstract
Polyamide/polyolefin blends have gained attention from the academia and the industry for several years. However, in order to optimize their properties, some drawbacks such as chemical incompatibility must be adequately overcome. This can be done by adding suitable compatibilizers. On the other hand, [...] Read more.
Polyamide/polyolefin blends have gained attention from the academia and the industry for several years. However, in order to optimize their properties, some drawbacks such as chemical incompatibility must be adequately overcome. This can be done by adding suitable compatibilizers. On the other hand, it is less known that suitable processing techniques may also lead to significant results. In a previous work on a low-density polyethylene/polyamide 6 (LDPE/PA6) blend, we found that the orientation due to elongational flow processing conditions could lead to an unexpected brittle–ductile transition. In this work, this phenomenon was further investigated and the attention was mainly focused on the effects that processing can have on the morphology and, as a consequence, on the final properties of a polymer blends. With regard to LDPE/PA6 blend, an important result was found, i.e., the effects on the ductility induced by the elongational flow orientation are similar to those obtained by using an ethylene-glycidyl methacrylate compatibilizer. Full article
(This article belongs to the Special Issue Polymer Blends and Compatibilization 2018)
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16 pages, 7267 KiB  
Article
Blending In Situ Polyurethane-Urea with Different Kinds of Rubber: Performance and Compatibility Aspects
by Muhammad Tahir, Gert Heinrich, Nasir Mahmood, Regine Boldt, Sven Wießner and Klaus Werner Stöckelhuber
Materials 2018, 11(11), 2175; https://doi.org/10.3390/ma11112175 - 2 Nov 2018
Cited by 13 | Viewed by 5825
Abstract
Specific physical and reactive compatibilization strategies are applied to enhance the interfacial adhesion and mechanical properties of heterogeneous polymer blends. Another pertinent challenge is the need of energy-intensive blending methods to blend high-tech polymers such as the blending of a pre-made hard polyurethane [...] Read more.
Specific physical and reactive compatibilization strategies are applied to enhance the interfacial adhesion and mechanical properties of heterogeneous polymer blends. Another pertinent challenge is the need of energy-intensive blending methods to blend high-tech polymers such as the blending of a pre-made hard polyurethane (-urea) with rubbers. We developed and investigated a reactive blending method to prepare the outstanding blends based on polyurethane-urea and rubbers at a low blending temperature and without any interfacial compatibilizing agent. In this study, the polyurethane-urea (PUU) was synthesized via the methylene diphenyl diisocyanate end-capped prepolymer and m-phenylene diamine based precursor route during blending at 100 °C with polar (carboxylated nitrile rubber (XNBR) and chloroprene rubber (CR)) and non-polar (natural rubber (NR), styrene butadiene rubber (sSBR), and ethylene propylene butadiene rubber (EPDM)) rubbers. We found that the in situ PUU reinforces the tensile response at low strain region and the dynamic-mechanical response up to 150 °C in the case of all used rubbers. Scanning electron microscopy reveals a stronger rubber/PUU interface, which promotes an effective stress transfer between the blend phases. Furthermore, energy filtered transmission electron microscopy (EFTEM) based elemental carbon map identifies an interphase region along the interface between the nitrile rubber and in situ PUU phases of this exemplary blend type. Full article
(This article belongs to the Special Issue Polymer Blends and Compatibilization 2018)
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21 pages, 6542 KiB  
Article
New Binary Blends of Ethylene-co-n-butyl Acrylate (EBA) Copolymer and Low Molecular Weight Rosin Ester Resin with Potential as Pressure Sensitive Adhesives
by Sara Sancho-Querol, Andrés Jesús Yáñez-Pacios and José Miguel Martín-Martínez
Materials 2018, 11(10), 2037; https://doi.org/10.3390/ma11102037 - 19 Oct 2018
Cited by 12 | Viewed by 5496
Abstract
For improving the adhesion property of ethylene-co-n-butyl acrylate copolymer (EBA) at ambient temperature, binary blends of EBA with 27 wt% n-butyl acrylate and different amounts (20–62 wt%) of low molecular weight hydrogenated glycerol rosin ester (ECH) resin have been prepared. The addition of [...] Read more.
For improving the adhesion property of ethylene-co-n-butyl acrylate copolymer (EBA) at ambient temperature, binary blends of EBA with 27 wt% n-butyl acrylate and different amounts (20–62 wt%) of low molecular weight hydrogenated glycerol rosin ester (ECH) resin have been prepared. The addition of glycerol rosin ester resin decreased the crystallinity and size of the ethylene domains of the EBA copolymer. The addition of up to 50 wt% (100 phr) ECH resin improved the compatibility with the EBA copolymer, whereas when more than 50 wt% (100 phr) ECH resin was added, the compatibility of the blends did not change but the viscoelastic properties were noticeably decreased. Furthermore, the compatibility was noticeably improved by adding only 20 wt% ECH resin although the best compromise between compatibility and viscoelasticity corresponded to the binary blend made with 43 wt% ECH resin. The EBA copolymer + ECH resin blends showed high tack (initial adhesion) at 25 °C and some of them even at 5 °C, and they have adequate 180° peel strength both to polar (polyethylene terephthalate-PET) and nonpolar (polypropylene-PP) substrate. Furthermore, all EBA copolymer + ECH resin blends showed high shear strength at 25 °C. Finally, the blend with 43 wt% ECH resin showed excellent pressure sensitive adhesive property exhibiting excellent creep, high tack, high 180° peel strength, and high single lap-shear strength. Full article
(This article belongs to the Special Issue Polymer Blends and Compatibilization 2018)
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17 pages, 4082 KiB  
Article
Polyether Sulfone-Based Epoxy Toughening: From Micro- to Nano-Phase Separation via PES End-Chain Modification and Process Engineering
by Yann Rosetti, Pierre Alcouffe, Jean-Pierre Pascault, Jean-François Gérard and Frédéric Lortie
Materials 2018, 11(10), 1960; https://doi.org/10.3390/ma11101960 - 12 Oct 2018
Cited by 49 | Viewed by 4516
Abstract
The toughness of a high-performance thermosetting epoxy network can be greatly improved by generating polyether sulfone−based macro- to nano-scale morphologies. Two polyethersulfones (PES) which only differ by their chain-end nature have been successively investigated as potential tougheners of a high-Tg thermoset matrix [...] Read more.
The toughness of a high-performance thermosetting epoxy network can be greatly improved by generating polyether sulfone−based macro- to nano-scale morphologies. Two polyethersulfones (PES) which only differ by their chain-end nature have been successively investigated as potential tougheners of a high-Tg thermoset matrix based on a mixture of trifunctional and difunctional aromatic epoxies and an aromatic diamine. For a given PES content, morphologies and toughness of the resulting matrices have been tuned by changing curing conditions and put into perspective with PES chain-end nature. Full article
(This article belongs to the Special Issue Polymer Blends and Compatibilization 2018)
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17 pages, 5712 KiB  
Article
3D Printing of PLA/clay Nanocomposites: Influence of Printing Temperature on Printed Samples Properties
by Bartolomeo Coppola, Nicola Cappetti, Luciano Di Maio, Paola Scarfato and Loredana Incarnato
Materials 2018, 11(10), 1947; https://doi.org/10.3390/ma11101947 - 11 Oct 2018
Cited by 155 | Viewed by 15242
Abstract
In this study, the possibility of using a layered silicate-reinforced polylactic acid (PLA) in additive manufacturing applications was investigated. In particular, the aim of this work was to study the influence of printing temperature in the 3D printing process of PLA/clay nanocomposites. For [...] Read more.
In this study, the possibility of using a layered silicate-reinforced polylactic acid (PLA) in additive manufacturing applications was investigated. In particular, the aim of this work was to study the influence of printing temperature in the 3D printing process of PLA/clay nanocomposites. For this reason, two PLA grades (4032D and 2003D, D-isomer content 1.5 and 4, respectively) were melt-compounded by a twin screw extruder with a layered silicate (Cloisite 30B) at 4 wt %. Then, PLA and PLA/clay feedstock filaments (diameter 1.75 mm) were produced using a single screw extruder. Dog-bone and prismatic specimens were 3D printed using the FDM technique at three different temperatures, which were progressively increased from melting temperature (185–200–215 °C for PLA 4032D and 165–180–195 °C for PLA 2003D). PLA and PLA/clay specimens were characterized using thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), and tensile tests. Moreover, the morphology of the 3D printed specimens was investigated using optical microscopy and contact angle measurements. The different polymer matrix and the resulting nanocomposite morphology strongly influenced 3D printed specimen properties. DMA on PLA/clay filaments reported an increase in storage modulus both at ambient temperature and above the glass transition temperature in comparison to neat PLA filaments. Furthermore, the presence of nanoclay increased thermal stability, as demonstrated by TGA, and acted as a nucleating agent, as observed from the DSC measurements. Finally, for 3D printed samples, when increasing printing temperature, a different behavior was observed for the two PLA grades and their nanocomposites. In particular, 3D printed nanocomposite samples exhibited higher elastic modulus than neat PLA specimens, but for PLA 4032D+C30B, elastic modulus increased at increasing printing temperature while for PLA 2003D+C30B slightly decreased. Such different behavior can be explained considering the different polymer macromolecular structure and the different nanocomposite morphology (exfoliated in PLA 4032D matrix and intercalated in PLA 2003D matrix). Full article
(This article belongs to the Special Issue Polymer Blends and Compatibilization 2018)
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9 pages, 1744 KiB  
Article
Temperature Dependence of Mechanical, Electrical Properties and Crystal Structure of Polyethylene Blends for Cable Insulation
by Lunzhi Li, Lisheng Zhong, Kai Zhang, Jinghui Gao and Man Xu
Materials 2018, 11(10), 1922; https://doi.org/10.3390/ma11101922 - 9 Oct 2018
Cited by 29 | Viewed by 4932
Abstract
There is a long-standing puzzle concerning whether polyethylene blends are a suitable substitution for cable-insulation-used crosslinking polyethylene (XLPE) especially at elevated temperatures. In this paper, we investigate temperature dependence of mechanical, electrical properties of blends with 70 wt % linear low density polyethylene [...] Read more.
There is a long-standing puzzle concerning whether polyethylene blends are a suitable substitution for cable-insulation-used crosslinking polyethylene (XLPE) especially at elevated temperatures. In this paper, we investigate temperature dependence of mechanical, electrical properties of blends with 70 wt % linear low density polyethylene (LLDPE) and 30 wt % high density polyethylene (HDPE) (abbreviated as 70 L-30 H). Our results show that the dielectric loss of 70 L-30 H is about an order of magnitude lower than XLPE, and the AC breakdown strength is 22% higher than XLPE at 90 °C. Moreover, the dynamic mechanical thermal analysis (DMA) measurement and hot set tests suggest that the blends shows optimal mechanical properties especially at high temperature with considerable temperature stability. Further scanning electron microscope (SEM) observation and X-ray diffraction (XRD) analysis uncover the reason for the excellent high temperature performance and temperature stability, which can be ascribed to the uniform fine-spherulite structure in 70 L-30 H blends with high crystallinity sustaining at high temperature. Therefore, our findings may enable the potential application of the blends as cable insulation material with higher thermal-endurance ability. Full article
(This article belongs to the Special Issue Polymer Blends and Compatibilization 2018)
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14 pages, 18621 KiB  
Article
Electrospinning of Ethylene Vinyl Acetate/Poly(Lactic Acid) Blends on a Water Surface
by Eliška Číková, Jaroslav Kuliček, Ivica Janigová and Mária Omastová
Materials 2018, 11(9), 1737; https://doi.org/10.3390/ma11091737 - 15 Sep 2018
Cited by 10 | Viewed by 6158
Abstract
The electrospinning of an ethylene vinyl acetate (EVA) copolymer with a vinyl acetate content of 28 wt.% is limited due to the solubility of the copolymer in standard laboratory conditions. Poly(lactic acid) (PLA) is a biodegradable polymer that can be electrospun easily. However, [...] Read more.
The electrospinning of an ethylene vinyl acetate (EVA) copolymer with a vinyl acetate content of 28 wt.% is limited due to the solubility of the copolymer in standard laboratory conditions. Poly(lactic acid) (PLA) is a biodegradable polymer that can be electrospun easily. However, PLA has limited applicability because it is brittle. Blends of these polymers are of interest in order to obtain new types of materials with counterbalanced properties originating from both polymeric compounds. The fibers were electrospun on a water surface from a solution mixture containing various weight ratios of both polymers using a dichloromethane and acetone (70:30 v/v) mixture as solvent. The morphologies of the prepared non-woven mats were examined by scanning electron microscopy (SEM), and the chemical composition was investigated by X-ray photoelectron spectroscopy (XPS) and by Fourier Transform Infrared Spectroscopy (FTIR). The fibers’ thermal properties and stability were examined, and the mechanical properties were tested. The results showed that the strength and flexibility of the blend samples were enhanced by the presence of PLA. Full article
(This article belongs to the Special Issue Polymer Blends and Compatibilization 2018)
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17 pages, 4532 KiB  
Article
POSS Nanofiller-Induced Enhancement of the Thermomechanical Properties in a Fluoroelastomer Terpolymer
by Daphné Berthier, Marie-Pierre Deffarges, Nicolas Berton, Mathieu Venin, Florian Lacroix, Bruno Schmaltz, Yohan Tendron, Eric Pestel, François Tran-Van and Stéphane Méo
Materials 2018, 11(8), 1358; https://doi.org/10.3390/ma11081358 - 6 Aug 2018
Cited by 13 | Viewed by 3962
Abstract
The present study reports on the use of three types of polyhedral oligomeric silsesquioxanes (POSS) nanoparticles with various organic substituents as fillers in a fluoroelastomer (FKM). A series of/POSS elastomer composite thin films is prepared. Microstructural SEM/TEM (scanning electron microscopy/transmission electron microscopy) imaging [...] Read more.
The present study reports on the use of three types of polyhedral oligomeric silsesquioxanes (POSS) nanoparticles with various organic substituents as fillers in a fluoroelastomer (FKM). A series of/POSS elastomer composite thin films is prepared. Microstructural SEM/TEM (scanning electron microscopy/transmission electron microscopy) imaging reveals a dispersion state allowing the presence of micron-sized domains. The influence of POSS content is studied in order to optimize thermal stability and mechanical properties of the composite thin films. Both POSS-A (with an acryloyl functional group and seven isobutyl substituents) and POSS-P (with eight phenyl substituents) lead to higher thermal stability and modulus of the composites, with respect to the unfilled FKM terpolymer matrix. covalent grafting of POSS-A onto the FKM network is found to play a critical role. Enhanced storage modulus in the rubbery plateau region (+210% at 200 °C for 20 phr) suggests that POSS-A is particularly suitable for high temperature applications. Full article
(This article belongs to the Special Issue Polymer Blends and Compatibilization 2018)
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10 pages, 1507 KiB  
Article
Morphology and Mechanical Properties of Polyamide 6/Polystyrene Blends Prepared by Diffusion and Subsequent Polymerization of Styrene in Polyamide 6 Pellets
by Yin-Le Tan, Cheng-Huan Huang, Zhao-Xia Guo and Jian Yu
Materials 2018, 11(5), 776; https://doi.org/10.3390/ma11050776 - 11 May 2018
Cited by 19 | Viewed by 3782
Abstract
Polyamide 6 (PA6)/polystyrene (PS) blend pellets were prepared by diffusion and subsequent polymerization of styrene in commercial PA6 pellets and processed into cuboid-shaped bars by injection molding. The average PS particle size in the bars was 240 nm, slightly higher than that in [...] Read more.
Polyamide 6 (PA6)/polystyrene (PS) blend pellets were prepared by diffusion and subsequent polymerization of styrene in commercial PA6 pellets and processed into cuboid-shaped bars by injection molding. The average PS particle size in the bars was 240 nm, slightly higher than that in the blend pellets (120 nm), showing that only limited coalescence occurs during injection molding. The mechanical properties of PA6/PS bars were investigated by tensile, flexural, and notched impact tests. A 41% increase in notched impact strength was found without decreasing the modulus, tensile, and flexural strengths and elongation to break, when compared with those of neat PA6 bars. These good mechanical properties were attributed to the small PS particle sizes, and the good interfacial adhesion between PS particles and the PA6 matrix resulted from the occurrence of PS grafting onto PA6 during the preparation of the blend pellets and injection molding. The water sorption and water-induced dimensional changes in PA6/PS bars were significantly less than those of neat PA6 bars because of the presence of the hydrophobic PS phase. This work reveals that the PA6/PS quasi-nanoblend pellets are useful stock for plastic production. Full article
(This article belongs to the Special Issue Polymer Blends and Compatibilization 2018)
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14 pages, 4387 KiB  
Article
Comparison of Ultem 9085 Used in Fused Deposition Modelling (FDM) with Polytherimide Blends
by Gianluca Cicala, Giulia Ognibene, Salvatore Portuesi, Ignazio Blanco, Mario Rapisarda, Eugenio Pergolizzi and Giuseppe Recca
Materials 2018, 11(2), 285; https://doi.org/10.3390/ma11020285 - 12 Feb 2018
Cited by 72 | Viewed by 9216
Abstract
Polyetherimide (PEI) blends modified by either polycarbonate (PC) or polyethylene terephthalate glycol-modified (PETG) were prepared. The latter modifier (PETG) was an industrial grade widely used for fused deposition modelling (FDM) printing. PEI blends were compared to Ultem 9085, which is the standard PEI [...] Read more.
Polyetherimide (PEI) blends modified by either polycarbonate (PC) or polyethylene terephthalate glycol-modified (PETG) were prepared. The latter modifier (PETG) was an industrial grade widely used for fused deposition modelling (FDM) printing. PEI blends were compared to Ultem 9085, which is the standard PEI grade for FDM printing in advanced applications. All the blends were thoroughly characterized in terms of their rheological, morphological, thermomechanical and tensile properties. Ultem 9085 showed improved rheology for processing over standard PEI. PEI/PC blends with 10 wt % of modifier developed here closely matched the viscosity behavior of Ultem 9085. On the other hand, the blends with low PC content (i.e., less than 20 wt %) outperformed Ultem 9085 in terms of thermal and tensile properties. When PETG was added, similar tensile properties to Ultem 9085 were found. The immiscibility for PC contents higher than 20 wt % deteriorated the tensile properties, making it less attractive for applications, although melt viscosity decreased further for increasing PC contents. Full article
(This article belongs to the Special Issue Polymer Blends and Compatibilization 2018)
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