Polymers

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4 pages, 186 KiB

Open AccessEditorial

Polymer Clay Nano-composites

by Stefano Leporatti

Polymers 2019, 11(9), 1445; https://doi.org/10.3390/polym11091445 - 3 Sep 2019

Cited by 8 | Viewed by 3278

Abstract

Clay–polymer composite materials is an exciting area of research and this Special Issue aims to address the current state-of-the-art of “Polymer Clay Nano-Composites” for several applications, among them antibacterial, environmental, water remediation, dental, drug delivery and others [...] Full article

(This article belongs to the Special Issue Polymer Clay Nano-composites)

Research

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14 pages, 1427 KiB

Open AccessArticle

Dispersion and Performance of a Nanoclay/Whey Protein Isolate Coating upon its Upscaling as a Novel Ready-to-Use Formulation for Packaging Converters

by Elodie Bugnicourt, Nicola Brzoska, Esra Kucukpinar, Severine Philippe, Enrico Forlin, Alvise Bianchin and Markus Schmid

Polymers 2019, 11(9), 1410; https://doi.org/10.3390/polym11091410 - 28 Aug 2019

Cited by 4 | Viewed by 4486

Abstract

Studies on composition optimisation showed that the mixing of nanoclays to whey protein-isolate (WPI)-based coating formulations offers an effective strategy to reduce the oxygen permeability of coated polymer films. The scaling up of the various processing stages of these formulations was undertaken to [...] Read more.

Studies on composition optimisation showed that the mixing of nanoclays to whey protein-isolate (WPI)-based coating formulations offers an effective strategy to reduce the oxygen permeability of coated polymer films. The scaling up of the various processing stages of these formulations was undertaken to prove their industrial feasibility. The aim was to investigate the effect of various preparation methods at different production scales (pilot- and semi-industrial scale) on the barrier performance and morphological properties of the applied nanocomposites. A nano-enhanced composition was converted into a so-called “ready-to-use” formulation by means of a solid-state pre-dispersion process using ball-milling. The process yielded a nearly dust-free, free-flowing powder containing agglomerated particles, which can easily be mixed with water. The preparation of a coating formulation using the ready-to-use granules and its upscaling for roll-to-roll converting at pilot- and semi-industrial scale was also successfully implemented. The effects of both the production at various scales and ultrasound treatment on the morphology and barrier performance of the nanocomposites were characterized by transmission electron microscopy, scanning electron microscopy, as well as oxygen permeability measurements. Results have shown that the addition of nanoclays to WPI-based coating formulations ultimately led to significantly reduced oxygen permeabilities to 0.59 cm³, 100 µm·m⁻²·d⁻¹·bar⁻¹ (barrier improvement factor, BIF of 5.4) and 0.62 cm³, 100 µm·m⁻²·d⁻¹·bar⁻¹ (BIF of 5.1) in cases of pilot- and semi-industrial-processed coatings, respectively, compared to a reference without nanoclay. In both cases, a similar degree of nanoparticle orientation was achieved. It was concluded that the solid state pre-dispersion of the nanoplatelets during the production of the ready-to-use formulation is the predominant process determining the ultimate degree of nanoparticle orientation and dispersion state. Full article

(This article belongs to the Special Issue Polymer Clay Nano-composites)

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10 pages, 3055 KiB

Open AccessArticle

High Performance Attapulgite/Polypyrrole Nanocomposite Reinforced Polystyrene (PS) Foam Based on Supercritical CO₂ Foaming

by Yidong Liu, Lingfeng Jian, Tianhua Xiao, Rongtao Liu, Shun Yi, Shiyang Zhang, Lingzhi Wang, Ruibin Wang and Yonggang Min

Polymers 2019, 11(6), 985; https://doi.org/10.3390/polym11060985 - 4 Jun 2019

Cited by 12 | Viewed by 3458

Abstract

CO₂ has been regarded as one of the most promising blowing agents for polystyrene (PS) foam due to its non-flammability, low price, nontoxicity, and eco-friendliness. However, the low solubility and fast diffusivity of CO₂ in PS hinder its potential applications. In [...] Read more.

CO₂ has been regarded as one of the most promising blowing agents for polystyrene (PS) foam due to its non-flammability, low price, nontoxicity, and eco-friendliness. However, the low solubility and fast diffusivity of CO₂ in PS hinder its potential applications. In this study, an attapulgite (ATP)/polypyrrole (PPy) nanocomposite was developed using the in situ polymerization method to generate the hierarchical cell texture for the PS foam based on the supercritical CO₂ foaming. The results demonstrated that the nanocomposite could act as an efficient CO₂ capturer enabling the random release of it during the foaming process. In contrast to the pure PS foam, the ATP/PPy nanocomposite reinforced PS foam is endowed with high cell density (up to 1.9 × 10⁶) and similar thermal conductivity as the neat PS foam, as well as high compression modulus. Therefore, the in situ polymerized ATP/PPy nanocomposite makes supercritical CO₂ foaming desired candidate to replace the widely used fluorocarbons and chlorofluorocarbons as PS blowing agents. Full article

(This article belongs to the Special Issue Polymer Clay Nano-composites)

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11 pages, 18992 KiB

Open AccessArticle

Cellulose Nanofibrils and Tubular Halloysite as Enhanced Strength Gelation Agents

by Vladimir Vinokurov, Andrei Novikov, Valentina Rodnova, Boris Anikushin, Mikhail Kotelev, Evgenii Ivanov and Yuri Lvov

Polymers 2019, 11(5), 919; https://doi.org/10.3390/polym11050919 - 24 May 2019

Cited by 15 | Viewed by 3713

Abstract

Silica gels are widely employed in water shutoff services, making them an essential tool in oil well management. Silica nanoparticles may serve as a strengthening additive for polymer hydrogels. In this study, we look at this statement from a different angle: What additives [...] Read more.

Silica gels are widely employed in water shutoff services, making them an essential tool in oil well management. Silica nanoparticles may serve as a strengthening additive for polymer hydrogels. In this study, we look at this statement from a different angle: What additives could be used to increase the strength of silica gels? Colloidal silica gels were prepared with various additives, and gel strength was measured by a Veiler–Rebinder apparatus. We found that cellulose nanofibrils considerably increase the gel strength (from 20–25 to 35–40 kPa), which is comparable with the industrial anionic polymer Praestol 2540. Cellulose nanofibrils can be produced from cheap industrial-grade cellulose with low-cost industrial chemicals and could be partially replaced by the even less expensive halloysite nanoclay. Cellulose nanofibrils produced from renewable sources and naturally occurring halloysite nanoclay could be used as complementary reinforcing agents. Full article

(This article belongs to the Special Issue Polymer Clay Nano-composites)

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11 pages, 4001 KiB

Open AccessArticle

The Stability of Intercalated Sericite by Cetyl Trimethylammonium Ion under Different Conditions and the Preparation of Sericite/Polymer Nanocomposites

by Yu Liang, Dexin Yang, Tao Yang, Ning Liang and Hao Ding

Polymers 2019, 11(5), 900; https://doi.org/10.3390/polym11050900 - 17 May 2019

Cited by 9 | Viewed by 3388

Abstract

Layered silicates are suitable for use as fillers in nanocomposites based on their particular features, such as large aspect ratio, easy availability, and chemical resistance. Among them, sericite is distinguished for its higher aspect ratio, higher resilience, and ultraviolet shielding and absorption. Previously, [...] Read more.

Layered silicates are suitable for use as fillers in nanocomposites based on their particular features, such as large aspect ratio, easy availability, and chemical resistance. Among them, sericite is distinguished for its higher aspect ratio, higher resilience, and ultraviolet shielding and absorption. Previously, sericite was structure-modified and intercalated by CTAB to expand its interlayer space. The intercalated sericite seems promising for use in the fabrication of polymer/sericite composites or pillared sericite. However, special attention should be paid to the stability of the intercalated sericite because the CTAB inside the layer may be de-intercalated, which would affect the interlayer spacing and its surface properties. In this article, the stability of the sericite intercalated by CTAB was tested by changing different variables, such as different washing solvents, different temperatures, ultrasonic cleaning, and different solution conditions. Finally, sericite/polymer nanocomposites were produced with the stable intercalated sericite, and showed excellent properties compared with pure epoxy resin. Full article

(This article belongs to the Special Issue Polymer Clay Nano-composites)

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16 pages, 3035 KiB

Open AccessArticle

Polyamine-Based Organo-Clays for Polluted Water Treatment: Effect of Polyamine Structure and Content

by Cinzia Cristiani, Elena Maria Iannicelli-Zubiani, Giovanni Dotelli, Elisabetta Finocchio, Paola Gallo Stampino and Maurizio Licchelli

Polymers 2019, 11(5), 897; https://doi.org/10.3390/polym11050897 - 16 May 2019

Cited by 13 | Viewed by 3588

Abstract

Hybrid materials based on clays and polyamines are supposed to be efficient heavy metals sorbents due to the well-known adsorption behaviour of the clay matrix and to the coordination properties of un-protonated amino groups. For this purpose, a montmorillonite clay was modified with [...] Read more.

Hybrid materials based on clays and polyamines are supposed to be efficient heavy metals sorbents due to the well-known adsorption behaviour of the clay matrix and to the coordination properties of un-protonated amino groups. For this purpose, a montmorillonite clay was modified with three different aliphatic polyamines: L6 and L10 have a linear structure with six and ten amino groups, respectively, while B14 is a branched polyamine with fourteen amino groups. Initial amine concentration was the main parameter investigated and data were fitted with Langmuir and Freundlich models. Interaction mechanisms between clay and amines were deeply investigated by different experimental techniques such as X-ray powder diffraction (XRD), thermal analysis measurements (DTG), Fourier Transform Infrared Spectroscopy (FT-IR) and diffuse reflectance (NIR) spectroscopy. Experimental results showed that the amount of amines efficiently immobilized in the solid phase can be increased by increasing the initial concentration of polyamines in the clay modification process. These data were best fitted by Freundlich model, indicating a presence of surface sites of different nature. In the resulting hybrid materials, neither the accessibility of the NH/NH₂ groups of the amines, nor the accessibility of the structural OH of the clay was hindered. Several preliminary tests in La ions’ uptake and release from aqueous solution were also carried out. In the conditions used for this study, total metal ion removal was achieved at sufficiently low linear amine loadings (i.e., 0.45 mmol/g_clay for the small L6 amine), suggesting that these hybrid materials are promising for the proposed application in environmental remediation. Full article

(This article belongs to the Special Issue Polymer Clay Nano-composites)

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17 pages, 5287 KiB

Open AccessEditor’s ChoiceArticle

Effect of Bifunctional Montmorillonite on the Thermal and Tribological Properties of Polystyrene/Montmorillonite Nanocomposites

by Chengcheng Yu, Yangchuan Ke, Xu Hu, Yi Zhao, Qingchun Deng and Shichao Lu

Polymers 2019, 11(5), 834; https://doi.org/10.3390/polym11050834 - 8 May 2019

Cited by 34 | Viewed by 5146

Abstract

In this work, the effect of doubly functionalized montmorillonite (MMT) on the structure, morphology, thermal, and tribological characteristics of the resulting polystyrene (PS) nanocomposites was investigated. The modification of the MMT was performed using a cationic surfactant and an anionic surfactant or a [...] Read more.

In this work, the effect of doubly functionalized montmorillonite (MMT) on the structure, morphology, thermal, and tribological characteristics of the resulting polystyrene (PS) nanocomposites was investigated. The modification of the MMT was performed using a cationic surfactant and an anionic surfactant or a silane coupling agent to increase the compatibility with PS matrix. The polystyrene/organo-montmorillonite (PS/OMMT) nanocomposite particles were prepared by soap-free emulsion polymerization. The OMMT was studied using Fourier-transform infrared (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The structural and morphological changes of PS/OMMT nanocomposites were further characterized by dynamic light scattering (DLS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The thermal stability of all the PS/OMMT nanocomposites was higher than that of the pure PS. The anti-wear properties of the polyalphaolefin (PAO) were significantly improved due to the introduction of the PS/OMMT nanocomposite particles. The nanocomposites prepared by a cationic surfactant and a silane coupling agent exhibited the best thermal stability and tribological performance. Our results provide the valuable insights needed to guide the design of lubrication and friction reducing materials. Full article

(This article belongs to the Special Issue Polymer Clay Nano-composites)

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11 pages, 2842 KiB

Open AccessArticle

Modification of Montmorillonite with Polyethylene Oxide and Its Use as Support for Pd⁰ Nanoparticle Catalysts

by Guiqing Shu, Jing Zhao, Xiu Zheng, Mengdie Xu, Qi Liu and Minfeng Zeng

Polymers 2019, 11(5), 755; https://doi.org/10.3390/polym11050755 - 29 Apr 2019

Cited by 9 | Viewed by 3086

Abstract

In this study, montmorillonite (MMT) was modified by intercalating polyethylene oxide (PEO) macromolecules between the interlayer spaces in an MMT-water suspension system. X-ray diffraction results revealed that the galleries of MMT were expanded significantly after intercalation of different loading of PEO. MMT/PEO 80/20 [...] Read more.

In this study, montmorillonite (MMT) was modified by intercalating polyethylene oxide (PEO) macromolecules between the interlayer spaces in an MMT-water suspension system. X-ray diffraction results revealed that the galleries of MMT were expanded significantly after intercalation of different loading of PEO. MMT/PEO 80/20 composite was chosen as the support platform for immobilization of Pd species in preparing novel heterogeneous catalysts. After immobilization of Pd species, the interlayer spacing of MMT/PEO (80/20) (1.52 nm) was further increased to 1.72 nm (Pd²⁺@MMT/PEO) and 1.73 nm (Pd⁰@MMT/PEO), confirming the well-immobilization of the Pd species in the interlayer spaces of PEO-modified MMT. High-resolution transmission electron microscopy (HR-TEM) observation results confirmed that Pd nanoparticles were confined inside the interlayer space of MMT and/or dispersed well on the outer surface of MMT. The conversion of Pd²⁺ to Pd⁰ species was evidenced by binding energy characterization with X-ray photo electron spectroscopy (XPS). The microstructure variation caused by the Pd immobilization was sensitively detected by positron annihilation lifetime spectroscopy (PALS) studies. The prepared Pd⁰@MMT/PEO (0.2/80/20) catalytic composite exhibits good thermal stability up to around 200 °C, and it showed high activities for Heck reactions between aryl iodides and butyl acrylates and could be recycled for five times. The correlations between the microstructure and properties of the Pd@MMT/PEO catalytic composites were discussed. Full article

(This article belongs to the Special Issue Polymer Clay Nano-composites)

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16 pages, 1598 KiB

Open AccessArticle

Fuzzy Optimization on the Synthesis of Chitosan-Graft-Polyacrylic Acid with Montmorillonite as Filler Material: A Case Study

by Angelo Earvin Sy Choi, Cybelle Morales Futalan and Jurng-Jae Yee

Polymers 2019, 11(4), 738; https://doi.org/10.3390/polym11040738 - 23 Apr 2019

Cited by 7 | Viewed by 3461

Abstract

In this paper, the synthesis of a chitosan–montmorillonite nanocomposite material grafted with acrylic acid is presented based on its function in a case study analysis. Fuzzy optimization is used for a multi-criteria decision analysis to determine the best desirable swelling capacity (Y [...] Read more.

In this paper, the synthesis of a chitosan–montmorillonite nanocomposite material grafted with acrylic acid is presented based on its function in a case study analysis. Fuzzy optimization is used for a multi-criteria decision analysis to determine the best desirable swelling capacity (Y_Q) of the material synthesis at its lowest possible variable cost. For Y_Q, the integrating the result’s cumulative uncertainty is an essential element to investigate the feasibility of the developed model equation. The Pareto set analysis is able to set the appropriate boundary limits for Y_Q and the variable cost. Two case studies are presented in determining the lowest possible cost: Case 1 for maximum Y_Q, and Case 2 for minimum Y_Q. These boundary limits were used in the fuzzy optimization to determine its global optimum results that achieved the overall satisfaction ratings of 67.2% (Case 1) and 52.3% (Case 2). The synthesis of the polyacrylic acid/chitosan material for Case 1 resulted in 305 g/g Y_Q and 10.8 USD/kg, while Case 2 resulted in 97 g/g Y_Q and 12.3 USD/kg. Thus, the fuzzy optimization approach proves to be a practical method for examining the best possible compromise solution based on the desired function to adequately synthesize a material. Full article

(This article belongs to the Special Issue Polymer Clay Nano-composites)

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21 pages, 2384 KiB

Open AccessEditor’s ChoiceArticle

Synthesis and Characterization of Dental Nanocomposite Resins Filled with Different Clay Nanoparticles

by Alexandros K. Nikolaidis, Elisabeth A. Koulaouzidou, Christos Gogos and Dimitris S. Achilias

Polymers 2019, 11(4), 730; https://doi.org/10.3390/polym11040730 - 22 Apr 2019

Cited by 38 | Viewed by 5695

Abstract

Nanotechnology comprises a promising approach towards the update of dental materials.The present study focuses on the reinforcement ofdental nanocomposite resins with diverse organomodified montmorillonite (OMMT) nanofillers. The aim is to investigate whether the presence of functional groups in the chemical structure of the [...] Read more.

Nanotechnology comprises a promising approach towards the update of dental materials.The present study focuses on the reinforcement ofdental nanocomposite resins with diverse organomodified montmorillonite (OMMT) nanofillers. The aim is to investigate whether the presence of functional groups in the chemical structure of the nanoclay organic modifier may virtually influence the physicochemical and/or the mechanical attitude of the dental resin nanocomposites. The structure and morphology of the prepared materials were investigated by means of wide angle X-ray diffraction and scanning electron microscopy analysis. Fourier transform infrared spectroscopy was used to determine the variation of the degree of conversion over time. Measurements of polymerization shrinkage and mechanical properties were conducted with a linear variable displacement transducer apparatus and a dynamometer, respectively. All the obtained nanocomposites revealed intercalated structures and most of them had an extensive filler distribution into the polymer matrix. Polymerization kinetics werefound to be influenced by the variance of the clay organomodifier, whilenanoclays with vinyl groups considerably increased the degree of conversion. Polymerization shrinkage was almost limited up to 50% by incorporating nanoclays. The absence of reactive groups in the OMMT structure may retain setting contraction atlow levels. An enhancement of the flexural modulus was observed, mainly by using clay nanoparticles decorated with methacrylated groups, along with a decrease in the flexural strength at a high filler loading. The overall best performance was found for the nanocomposites with OMMTs containing double bonds. The significance of the current work relies on providing novel information about chemical interactions phenomena between nanofillers and the organic matrix towards the improvement of dental restorative materials. Full article

(This article belongs to the Special Issue Polymer Clay Nano-composites)

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20 pages, 4725 KiB

Open AccessArticle

Synthesis and Characterization of Clay Polymer Nanocomposites of P(4VP-co-AAm) and Their Application for the Removal of Atrazine

by Jorge A. Ramírez-Gómez, Javier Illescas, María del Carmen Díaz-Nava, Claudia Muro-Urista, Sonia Martínez-Gallegos and Ernesto Rivera

Polymers 2019, 11(4), 721; https://doi.org/10.3390/polym11040721 - 19 Apr 2019

Cited by 10 | Viewed by 3909

Abstract

Atrazine (ATZ) is an herbicide which is applied to the soil, and its mechanism of action involves the inhibition of photosynthesis. One of its main functions is to control the appearance of weeds in crops, primarily in corn, sorghum, sugar cane, and wheat; [...] Read more.

Atrazine (ATZ) is an herbicide which is applied to the soil, and its mechanism of action involves the inhibition of photosynthesis. One of its main functions is to control the appearance of weeds in crops, primarily in corn, sorghum, sugar cane, and wheat; however, it is very toxic for numerous species, including humans. Therefore, this work deals with the adsorption of ATZ from aqueous solutions using nanocomposite materials, synthesized with two different types of organo-modified clays. Those were obtained by the free radical polymerization of 4-vinylpyridine (4VP) and acrylamide (AAm) in different stoichiometric ratios, using tetrabutylphosphonium persulfate (TBPPS) as a radical initiator and N,N′-methylenebisacrylamide (BIS) as cross-linking agent. The structural, morphological, and textural characteristics of clays, copolymers, and nanocomposites were determined through different analytical and instrumental techniques, i.e., X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). Adsorption kinetics experiments of ATZ were determined with the modified and synthesized materials, and the effect of the ratio between 4VP and AAm moieties on the removal capacities of the obtained nanocomposites was evaluated. Finally, from these sets of experiments, it was demonstrated that the synthesized nanocomposites with higher molar fractions of 4VP obtained the highest removal percentages of ATZ. Full article

(This article belongs to the Special Issue Polymer Clay Nano-composites)

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18 pages, 5010 KiB

Open AccessArticle

Buildup of Multi-Ionic Supramolecular Network Facilitated by In-Situ Intercalated Organic Montmorillonite in 1,2-Polybutadiene

by Jinhui Liu, Di Li, Xiangshuai Zhao, Jieting Geng, Jing Hua and Xin Wang

Polymers 2019, 11(3), 492; https://doi.org/10.3390/polym11030492 - 13 Mar 2019

Cited by 10 | Viewed by 4057

Abstract

The development of a sacrificial bond provided unique inspiration for the design of advanced elastomers with excellent mechanical properties, but it is still a huge challenge to construct a homogenous polar sacrificial network in a nonpolar elastomer. In this effort, we proposed a [...] Read more.

The development of a sacrificial bond provided unique inspiration for the design of advanced elastomers with excellent mechanical properties, but it is still a huge challenge to construct a homogenous polar sacrificial network in a nonpolar elastomer. In this effort, we proposed a novel strategy to engineer a multi-ionic network into a covalently cross-linked 1,2-polybutadiene (1,2-PB) facilitated by in-situ intercalated organic montmorillonite (OMMT) without phase separation. XRD, SEM, and TEM analysis were carried out to characterize the microstructure of the resulting polymers. Crosslinking density, dielectric performance, and cyclic tensile tests were used to demonstrate the interaction of zinc methacrylate (ZDMA) and OMMT. The dynamic nature of ionic bonds allowed it to rupture and reform to dissipate energy efficiently. Stretching orientation brought parallelism between polymer chains and OMMT layers which was beneficial for the reconstruction of the ionic network, ultimately resulting in high strength and a low stress relaxation rate. Overall, our work presented the design of a uniform and strong sacrificial network in the nano-clay/elastomer nanocomposite with outstanding mechanical performances under both static and dynamic conditions. Full article

(This article belongs to the Special Issue Polymer Clay Nano-composites)

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14 pages, 3271 KiB

Open AccessEditor’s ChoiceArticle

Hyaluronic Acid-Decorated Laponite^® Nanocomposites for Targeted Anticancer Drug Delivery

by Tingting Jiang, Guangxiang Chen, Xiangyang Shi and Rui Guo

Polymers 2019, 11(1), 137; https://doi.org/10.3390/polym11010137 - 14 Jan 2019

Cited by 34 | Viewed by 5962

Abstract

In this study, hyaluronic acid (HA), a natural polysaccharide that can specifically bind to CD44 receptors, was conjugated onto laponite^® (LAP) nanodisks for the encapsulation and specific delivery of the anti-cancer drug doxorubicin (DOX) to CD44-overexpressed cancer cells. The prepared LM-HA could [...] Read more.

In this study, hyaluronic acid (HA), a natural polysaccharide that can specifically bind to CD44 receptors, was conjugated onto laponite^® (LAP) nanodisks for the encapsulation and specific delivery of the anti-cancer drug doxorubicin (DOX) to CD44-overexpressed cancer cells. The prepared LM-HA could encapsulate DOX efficiently and release drug in a continuous manner with pH-responsiveness. In vitro cell viability assay proved that LM-HA had good biocompatibility, and drug-loaded LM-HA/DOX exhibited targeted anti-tumor effects against HeLa cells with CD44 receptors overexpressed. In addition, the flow cytometric detection and confocal laser scanning microscope results confirmed that LM-HA/DOX could be specifically internalized by HeLa cells via CD44-mediated endocytosis. Therefore, the HA-modified LAP nanodisks with high drug loading efficiency, pH-sensitive drug release properties and CD44 targetability might be an efficient nanoplatform for cancer chemotherapy. Full article

(This article belongs to the Special Issue Polymer Clay Nano-composites)

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14 pages, 4925 KiB

Open AccessArticle

Synergistic Effect of Halloysite Nanotubes and Glycerol on the Physical Properties of Fish Gelatin Films

by Xiaohu Qiang, Songyi Zhou, Zhuo Zhang, Qiling Quan and Dajian Huang

Polymers 2018, 10(11), 1258; https://doi.org/10.3390/polym10111258 - 13 Nov 2018

Cited by 11 | Viewed by 3728

Abstract

Fish gelatin (FG)/glycerol (GE)/halloysite (HT) composite films were prepared by casting method. The morphology of the composite films was observed by scanning electron microscopy (SEM). The effects of HT and GE addition on the mechanical properties, water resistance and optical properties of the [...] Read more.

Fish gelatin (FG)/glycerol (GE)/halloysite (HT) composite films were prepared by casting method. The morphology of the composite films was observed by scanning electron microscopy (SEM). The effects of HT and GE addition on the mechanical properties, water resistance and optical properties of the composites were investigated. Results showed that with increasing GE content, the elongation at composite breaks increased significantly, but their tensile strength (TS) and water resistance decreased. SEM results showed that GE can partly promote HT dispersion in composites. TS and water resistance also increased with the addition of HTs. Well-dispersed HTs in the FG matrix decreased the moisture uptake and water solubility of the composites. All films showed a transparency higher than 80% across the visible light region (400–800 nm), thereby indicating that light transmittance of the resulting nanocomposites was slightly affected by GE and HTs. Full article

(This article belongs to the Special Issue Polymer Clay Nano-composites)

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13 pages, 1907 KiB

Open AccessArticle

Grafting Halloysite Nanotubes with Amino or Carboxyl Groups onto Carbon Fiber Surface for Excellent Interfacial Properties of Silicone Resin Composites

by Xiandong Zhang and Guangshun Wu

Polymers 2018, 10(10), 1171; https://doi.org/10.3390/polym10101171 - 22 Oct 2018

Cited by 29 | Viewed by 4907

Abstract

The quality of interphase in carbon fibers (CFs) composites makes a key contribution to overall performance of composites. Here, we achieved for the first time the chemical grafting of halloysite nanotubes (HNTs) with amino or carboxyl groups onto the CFs surface aiming to [...] Read more.

The quality of interphase in carbon fibers (CFs) composites makes a key contribution to overall performance of composites. Here, we achieved for the first time the chemical grafting of halloysite nanotubes (HNTs) with amino or carboxyl groups onto the CFs surface aiming to increase composites interfacial strength. HNTs were grafted using 3-aminopropyltriethoxysilane (APS) followed by succinic anhydride treatment, and HNTs with amino groups (HNT–NH₂) or carboxyl groups (HNT–COOH) were separately introduced into the interphase of composites. Functional groups of HNTs and fiber surface structures were characterized, which confirmed the modification success. The wettability between the modified CFs and resin have been enhanced obviously based on the improved fiber polarity and enhanced surface roughness by the introduced two functionalized HNTs with the uniform distributions onto fiber surface. Moreover, interfacial properties and anti-hydrothermal aging behaviors of modified methylphenylsilicone resin (MPSR) composites were improved significantly, especially for HNT–COOH grafting. In addition, the interfacial reinforcement mechanisms for untreated and modified CF composites are discussed and compared. Full article

(This article belongs to the Special Issue Polymer Clay Nano-composites)

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7 pages, 1668 KiB

Open AccessCommunication

Nanoscale Mechanical Properties and Indentation Recovery of PI@GO Composites Measured Using AFM

by Ji Zhou, Qiang Cai and Fu Xu

Polymers 2018, 10(9), 1020; https://doi.org/10.3390/polym10091020 - 13 Sep 2018

Cited by 9 | Viewed by 4109

Abstract

Polyimide@graphene oxide (PI@GO) composites were prepared by way of a simple solution blending method. The nanoscale hardness and Young’s modulus of the composites were measured using nanoindentation based on atomic force microscopy (AFM). A nanoscale hardness of ~0.65 GPa and an elastic modulus [...] Read more.

Polyimide@graphene oxide (PI@GO) composites were prepared by way of a simple solution blending method. The nanoscale hardness and Young’s modulus of the composites were measured using nanoindentation based on atomic force microscopy (AFM). A nanoscale hardness of ~0.65 GPa and an elastic modulus of ~6.5 GPa were reached with a load of ~55 μN. The indentation recovery on the surface of PI@GO was evaluated. The results show that relatively low GO content can remarkably improve the nanoscale mechanical properties of PI. Full article

(This article belongs to the Special Issue Polymer Clay Nano-composites)

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Review

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18 pages, 2823 KiB

Open AccessReview

Advances in Halloysite Nanotubes–Polysaccharide Nanocomposite Preparation and Applications

by Yang Wu, Yongzhi Zhang, Junping Ju, Hao Yan, Xiaoyu Huang and Yeqiang Tan

Polymers 2019, 11(6), 987; https://doi.org/10.3390/polym11060987 - 4 Jun 2019

Cited by 42 | Viewed by 6360

Abstract

Halloysite nanotubes (HNTs), novel 1D natural materials with a unique tubular nanostructure, large aspect ratio, biocompatibility, and high mechanical strength, are promising nanofillers to improve the properties of polymers. In this review, we summarize the recent progress toward the development of polysaccharide-HNTs composites, [...] Read more.

Halloysite nanotubes (HNTs), novel 1D natural materials with a unique tubular nanostructure, large aspect ratio, biocompatibility, and high mechanical strength, are promising nanofillers to improve the properties of polymers. In this review, we summarize the recent progress toward the development of polysaccharide-HNTs composites, paying attention to the main existence forms and wastewater treatment application particularly. The purification of HNTs and fabrication of the composites are discussed first. Polysaccharides, such as alginate, chitosan, starch, and cellulose, reinforced with HNTs show improved mechanical, thermal, and swelling properties. Finally, we summarize the unique characteristics of polysaccharide-HNTs composites and review the recent development of the practical applications. Full article

(This article belongs to the Special Issue Polymer Clay Nano-composites)

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