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14 pages, 11376 KiB

Open AccessArticle

Reactive Comb Polymer Compatibilized Immiscible PVDF/PLLA Blends: Effects of the Main Chain Structure of Compatibilizer

by Xin Yang, Jinxing Song, Hengti Wang, Qingqing Lin, Xianhua Jin, Xin Yang and Yongjin Li

Polymers 2020, 12(3), 526; https://doi.org/10.3390/polym12030526 - 02 Mar 2020

Cited by 6 | Viewed by 4127

The compatibilizer with double comb structure has a superior compatibilizing effect for immiscible polymer blends due to the symmetrical structure on both sides of main chains. Extensive study related to the architectural effects of compatibilizer on the compatibilization has mainly focused on the [...] Read more.

The compatibilizer with double comb structure has a superior compatibilizing effect for immiscible polymer blends due to the symmetrical structure on both sides of main chains. Extensive study related to the architectural effects of compatibilizer on the compatibilization has mainly focused on the side chains. We investigated the influence of the compatibilizer-main-chain structure on the compatibilizing effect for immiscible poly(vinylidene fluoride)/poly(L-lactic acid) (PVDF/PLLA) blends. Two reactive-comb compatibilizers with polystyrene (PS) and polymethylmethacrylate (PMMA) as main chains and PMMA as the side chains have been synthesized. PS is immiscible with both PLLA and PVDF, while PMMA is miscible with PVDF. It was found that both compatibilizers can improve the compatibility between the PLLA and PVDF, with different compatibilization effects. In the PVDF/PLLA (50/50) blends, 1 wt.% poly(styrene-co-glycidyl methacrylate)-graft-poly(methyl methacrylate) (RC–SG) tuned the morphology from the droplet-in-matrix structure to the co-continuous structure, while the blends with poly(methyl methacrylate-co-glycidyl methacrylate)-graft-poly(methyl methacrylate) (RC–MMG) kept the sea-island structure with even 3 wt.% loading. Moreover, RC–SG induces a wider co-continuous interval range than RC–MMG. The co-continuous structure obtained by RC–SG was also more stable than that by RC–MMG. It was further found that RC–SG-compatibilized PVDF/PLLA blends exhibit higher mechanical properties than the RC–MMG-compatibilized blends. Full article

(This article belongs to the Special Issue Multiphase Structure of Polymeric Materials and Physical Properties)

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14 pages, 2996 KiB

Open AccessArticle

Designing a Polymer-Based Hybrid with Simultaneously Improved Mechanical and Damping Properties via a Multilayer Structure Construction: Structure Evolution and a Damping Mechanism

by Kangming Xu, Qiaoman Hu, Hong Wu, Shaoyun Guo and Fengshun Zhang

Polymers 2020, 12(2), 446; https://doi.org/10.3390/polym12020446 - 14 Feb 2020

Cited by 11 | Viewed by 2858

Abstract

Though hindered phenol/polymer-based hybrid damping materials, with an excellent loss factor, attract more and more attention, the significantly decreased mechanical property and the narrow damping temperature range limit the application of such promising materials. To solve the problems, a polyurethane (hindered phenol)/polyvinyl acetate [...] Read more.

Though hindered phenol/polymer-based hybrid damping materials, with an excellent loss factor, attract more and more attention, the significantly decreased mechanical property and the narrow damping temperature range limit the application of such promising materials. To solve the problems, a polyurethane (hindered phenol)/polyvinyl acetate multilayer system with varied layer numbers was prepared in this study. The multilayer microstructures were first verified through the scanning electron microscopy. A subsequent molecular dynamics simulation revealed the promoted diffusion of polyurethane (hindered phenol) and polyvinyl acetate layers, the compact chain packing of the polyurethane (hindered phenol) layer, the extended chain packing of the polyvinyl acetate layer, the intermolecular hydrogen bonds among the three components and the enhanced interface interactions between the two layers in a quantitative manner. Further the mechanical and dynamic mechanical analysis detected the successful preparation of the multilayer hybrids with simultaneously improved mechanical and damping properties. Then, by a combination of molecular dynamics simulation and experiment, the relationship between the structure evolution and the properties of the multilayer hybrids was established, which was expected to have some guiding significance for industrial production. Full article

(This article belongs to the Special Issue Multiphase Structure of Polymeric Materials and Physical Properties)

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16 pages, 14347 KiB

Open AccessArticle

The Effect of Crystallinity on the Toughness of Cast Polyamide 6 Rods with Different Diameters

by Miklós Odrobina, Tamás Deák, László Székely, Tamás Mankovits, Róbert Zsolt Keresztes and Gábor Kalácska

Polymers 2020, 12(2), 293; https://doi.org/10.3390/polym12020293 - 02 Feb 2020

Cited by 11 | Viewed by 4405

Abstract

The present paper concentrates on the toughness and the degree of crystallinity of the magnesium-catalyzed polyamide 6 rods cast in different diametres, which are commonly used for gear manufacturing. Its toughness cannot be regarded as a constant feature due to the casting technology. [...] Read more.

The present paper concentrates on the toughness and the degree of crystallinity of the magnesium-catalyzed polyamide 6 rods cast in different diametres, which are commonly used for gear manufacturing. Its toughness cannot be regarded as a constant feature due to the casting technology. The mechanical properties of the semi-finished products are sensitive to the manufactured dimension, e.g., cast diameter, which are investigated by the Charpy impact test and tensile impact test. It is generally accepted that the impact strength and tensile-impact strength correlate with the degree of crystallinity beside many other material’s feature. Crystallinity is evaluated by Differential Scanning Calorimetry. The aim of this study is to determine the relationship between toughness and crystallinity of the magnesium-catalyzed cast PA6 rods with different diameters. For the research cast rods between 40 and 300 mm diameter were selected in seven-dimensional steps. Based on the results, it was found that the toughness depends strongly on the diameter size. Furthermore, it is proved that the crystallinity explains 62.3% of the variation of the Charpy’s impact strengths, while the tensile impact method was not suitable to detect the difference between the test samples. Full article

(This article belongs to the Special Issue Multiphase Structure of Polymeric Materials and Physical Properties)

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17 pages, 12479 KiB

Open AccessArticle

Correlation between Drop Impact Energy and Residual Compressive Strength According to the Lamination of CFRP with EVA Sheets

by Sun-Ho Go, Min-Sang Lee, Chang-Gi Hong, Lee-Ku Kwac and Hong-Gun Kim

Polymers 2020, 12(1), 224; https://doi.org/10.3390/polym12010224 - 16 Jan 2020

Cited by 6 | Viewed by 2745

Abstract

Carbon-fiber-reinforced plastic is an important building material; however, its application is limited because of its brittleness, leading to vulnerability under shock. Thus, the strength performance of carbon-fiber-reinforced plastics needs to be improved. Here, the drop impact test was conducted to analyze the impact [...] Read more.

Carbon-fiber-reinforced plastic is an important building material; however, its application is limited because of its brittleness, leading to vulnerability under shock. Thus, the strength performance of carbon-fiber-reinforced plastics needs to be improved. Here, the drop impact test was conducted to analyze the impact energy and fracture characteristics of carbon-fiber-reinforced plastics and ethylene vinyl acetate sheets. The compression after impact test was performed to assess the residual compressive strength. The thermal energy generated was measured as change in temperature at the time of fracture to investigate the relationship between thermal and mechanical properties. The impact absorption efficiency of 100% was achieved when the carbon-fiber-reinforced plastics specimen was laminated with four or more sheets of ethylene vinyl acetate. The thermal energy generated during impact, the impact load, and the compression after impact test strength was reduced with the increasing number of laminated ethylene vinyl acetate layers. Our results showed that, by carefully selecting the optimal conditions of fabricating the carbon-fiber-reinforced plastic/ethylene vinyl acetate composites, carbon composite materials can be used for impact mitigation. Full article

(This article belongs to the Special Issue Multiphase Structure of Polymeric Materials and Physical Properties)

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22 pages, 11212 KiB

Open AccessArticle

Crystalline Characteristics and Their Influence in the Mechanical Performance in Poly(ε-Caprolactone) / High Density Polyethylene Blends

by Enrique Blázquez-Blázquez, Ernesto Pérez, Vicente Lorenzo and María L. Cerrada

Polymers 2019, 11(11), 1874; https://doi.org/10.3390/polym11111874 - 13 Nov 2019

Cited by 17 | Viewed by 5190

Abstract

Blends of poly(ε-caprolactone) (PCL) and high-density polyethylene (HDPE) have been prepared at different compositions in order to assess the effect of HDPE on gas transport and mechanical behaviors of PCL. Previous to this evaluation, a complete morphological, structural, and thermal characterization were performed [...] Read more.

Blends of poly(ε-caprolactone) (PCL) and high-density polyethylene (HDPE) have been prepared at different compositions in order to assess the effect of HDPE on gas transport and mechanical behaviors of PCL. Previous to this evaluation, a complete morphological, structural, and thermal characterization were performed using techniques, including SEM, contact angle, FTIR, differential scanning calorimetry, and X-ray diffraction with synchrotron radiation at small and wide angles. Low HDPE incorporations allow interactions to be established at interfaces in the amorphous regions and the enhancement of the mechanical performance. Consequently, the addition of a small amount of HDPE (ranging from 5 to 10 wt%) appears to be appropriate in certain bio-applications where a higher mechanical behavior is required. Full article

(This article belongs to the Special Issue Multiphase Structure of Polymeric Materials and Physical Properties)

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12 pages, 2336 KiB

Open AccessArticle

Chlorination Treatment of Meta-Aramid Fibrids and Its Effects on Mechanical Properties of Polytetramethylene Ether Glycol/Toluene Diisocyanate (PTMEG/TDI)-Based Polyurethane Composites

by Wuyang Lu, Yuhua Yi, Chunping Ning, Mingliang Ge and Jahangir Alam S.M.

Polymers 2019, 11(11), 1794; https://doi.org/10.3390/polym11111794 - 01 Nov 2019

Cited by 6 | Viewed by 2826

Abstract

Meta-aramid fibrids (MAF) have attracted much attention. However, it is difficult for this high mechanical performance fiber to form sufficient interface adhesion between the MAF and polyurethane (PU) matrix due to the chemical inertness of its surface. Thus, the surface activity of MAF [...] Read more.

Meta-aramid fibrids (MAF) have attracted much attention. However, it is difficult for this high mechanical performance fiber to form sufficient interface adhesion between the MAF and polyurethane (PU) matrix due to the chemical inertness of its surface. Thus, the surface activity of MAF should be improved to obtain a high-performance MAF/PU composite. A novel methodology to modify the surface of MAF with a sodium dichloroisocyanurate solution (DCCNa) was developed to obtain chlorinated MAF (MAFC) in this study. A series of MAFC/PU composites was prepared by in situ polymerization processes. The results of Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) demonstrated that the chlorine-contained chemical groups were introduced onto the MAF surfaces after chlorination. Dynamic contact angle analysis (DCAA) revealed that the surface wettability and the surface free energy of the MAFC were significantly improved, which allowed for strong chemical bonding to PU. Scanning electron microscopy (SEM) showed a uniform distribution of MAFC and good interfacing bonding between the MAFC and PU. With the incorporation of 1.5 wt% MAFC into the polyurethane matrix, the tensile and tear strength values of MAFC/PU were 36.4 MPa and 80.1 kN·m⁻¹ respectively, corresponding to improvements of approximately 43.3% and 21.1%, as compared to those of virgin PU as 25.4 MPa and 66.1 kN·m⁻¹, respectively. Full article

(This article belongs to the Special Issue Multiphase Structure of Polymeric Materials and Physical Properties)

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18 pages, 5064 KiB

Open AccessArticle

Piezoelectric Films Based on Polyethylene Modified by Aluminosilicate Filler

by Halina Kaczmarek, Bogusław Królikowski, Marta Chylińska, Ewa Klimiec and Dagmara Bajer

Polymers 2019, 11(8), 1345; https://doi.org/10.3390/polym11081345 - 13 Aug 2019

Cited by 11 | Viewed by 3430

Abstract

The development, universality and miniaturization of electronic devices leads to the search for new piezoelectric materials, among which recently, polymers play an increasingly important role. In this work, composites based on two types of polyethylene—high density polyethylene (HDPE), and medium density polyethylene (MDPE)—and [...] Read more.

The development, universality and miniaturization of electronic devices leads to the search for new piezoelectric materials, among which recently, polymers play an increasingly important role. In this work, composites based on two types of polyethylene—high density polyethylene (HDPE), and medium density polyethylene (MDPE)—and aluminosilicate fillers were obtained by extrusion process. This method allowed obtaining flexible electrets in the form of a thin film after polarization under a constant electric field of 100 V/μm. The morphology of the composites was characterized by scanning electron microscopy, whereas the crystallinity was determined by X-ray diffraction. The mechanical properties and thermal stability of the composites were examined by means of tensile tests and thermogravimetry, respectively. The piezoelectric characteristics were appointed by measuring the electric charge and the voltage in the polarized samples. Piezoelectric coefficients, and the stability of electrets over time were also determined. Moreover, the effect of film orientation on piezoelectric properties was investigated. Composites with appropriate morphology (i.e., well dispersed filler particles in the polymer matrix and formed holes) were obtained which ensured permanent electrical polarization. It was found that the best piezoelectric, mechanical properties and thermal stability exhibits HDPE composite with 5% of aluminosilicate filler. Full article

(This article belongs to the Special Issue Multiphase Structure of Polymeric Materials and Physical Properties)

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Review

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31 pages, 2487 KiB

Open AccessEditor’s ChoiceReview

Description of the Droplet Size Evolution in Flowing Immiscible Polymer Blends

by Ivan Fortelný and Josef Jůza

Polymers 2019, 11(5), 761; https://doi.org/10.3390/polym11050761 - 30 Apr 2019

Cited by 24 | Viewed by 4292

Abstract

Control of the phase structure evolution in flowing immiscible polymer blends during their mixing and processing is fundamental for tailoring of their performance. This review summarizes present state of understanding and predictability of the phase structure evolution in flowing immiscible polymer blends with [...] Read more.

Control of the phase structure evolution in flowing immiscible polymer blends during their mixing and processing is fundamental for tailoring of their performance. This review summarizes present state of understanding and predictability of the phase structure evolution in flowing immiscible polymer blends with dispersed structure. Results of the studies of the droplet breakup in flow, important for determination of the droplet breakup frequency and of the size distribution of the daughter droplets, are reviewed. Theories of the flow-induced coalescence providing equations for collision efficiency are discussed. Approximate analytic expressions reliably describing dependence of the collision efficiency on system parameters are presented. Available theories describing the competition between the droplet breakup and coalescence in flow are summarized and approximations used in their derivation are discussed. Problems with applicability of available theories on prediction of the droplet size evolution during mixing and processing of immiscible polymer blends, which have not been broadly discussed so far, are addressed. Full article

(This article belongs to the Special Issue Multiphase Structure of Polymeric Materials and Physical Properties)

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