Editorial

4 pages, 207 KiB

Open AccessEditorial

by Jesús-María García-Martínez and Emilia P. Collar

Polymers 2021, 13(1), 86; https://doi.org/10.3390/polym13010086 - 28 Dec 2020

Cited by 13 | Viewed by 2979

According to the IUPAC (International Union of Pure and Applied Chemistry), a hybrid material is that composed of an intimate mixture of inorganic components, organic components, or both types of components which usually interpenetrate on scales of less than 1 μm [...] Full article

(This article belongs to the Special Issue Organic-Inorganic Hybrid Materials)

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12 pages, 5866 KiB

Open AccessArticle

Regulation of Polyvinyl Alcohol/Sulfonated Nano-TiO₂ Hybrid Membranes Interface Promotes Diffusion Dialysis

by Yuxia Liang, Xiaonan Huang, Lanzhong Yao, Ru Xia, Ming Cao, Qianqian Ge, Weibin Zhou, Jiasheng Qian, Jibin Miao and Bin Wu

Polymers 2021, 13(1), 14; https://doi.org/10.3390/polym13010014 - 23 Dec 2020

Cited by 7 | Viewed by 2001

Abstract

It is important to emphasize that the adjustment of an organic–inorganic interfacial chemical environment plays an important role during the separation performance of composite materials. In this paper, a series of hybrid membranes were prepared by blending polyvinyl alcohol (PVA) solution and sulfonated [...] Read more.

It is important to emphasize that the adjustment of an organic–inorganic interfacial chemical environment plays an important role during the separation performance of composite materials. In this paper, a series of hybrid membranes were prepared by blending polyvinyl alcohol (PVA) solution and sulfonated nano-TiO₂ (SNT) suspension. The effects of different interfacial chemical surroundings on ions transfer were explored by regulating the dosage content of SNT. The as-prepared membranes exhibited high thermal and mechanical stability, with initial decomposition temperatures of 220–253 °C, tensile strengths of 31.5–53.4 MPa, and elongations at break of 74.5–146.0%. The membranes possessed moderate water uptake (WR) values of 90.9–101.7% and acceptable alkali resistances (swelling degrees were 187.2–206.5% and weight losses were 10.0–20.8%). The as-prepared membranes were used for the alkali recovery of a NaOH/Na₂WO₄ system via the diffusion dialysis process successfully. The results showed that the dialysis coefficients of OH⁻ (U_OH) were in a range of 0.013–0.022 m/h, and separate factors (S) were in an acceptable range of 22–33. Sulfonic groups in the interfacial regions and –OH in the PVA main chains were both deemed to play corporate roles during the transport of Na⁺ and OH⁻. Full article

(This article belongs to the Special Issue Organic-Inorganic Hybrid Materials)

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13 pages, 2140 KiB

Open AccessArticle

On the Combined Effect of Both the Reinforcement and a Waste Based Interfacial Modifier on the Matrix Glass Transition in iPP/a-PP-pPBMA/Mica Composites

by Jesús-María García-Martínez and Emilia P. Collar

Polymers 2020, 12(11), 2606; https://doi.org/10.3390/polym12112606 - 06 Nov 2020

Cited by 5 | Viewed by 1745

Abstract

This work deals with the changes of the glass transition temperature (T_g) of the polymer in polypropylene/mica composites due to the combined and synergistic effect of the reinforcement and the interfacial modifier. In our case, we studied the effect on T [...] Read more.

This work deals with the changes of the glass transition temperature (T_g) of the polymer in polypropylene/mica composites due to the combined and synergistic effect of the reinforcement and the interfacial modifier. In our case, we studied the effect on T_g of platy mica and an interfacial modifier with p-phenylen-bis-maleamic acid (pPBMA) grafted groups onto atactic polypropylene (aPP-pPBMA). This one contains 5.0 × 10⁻⁴ g·mol⁻¹ (15% w/w) grafted pPBMA and was previously obtained by the author’s labs by using industrial polymerization wastes (aPP). The objective of the article must be perceived as two-fold. On one hand, the determination of the changes in the glass transition temperature of the isotactic polypropylene phase (iPP) due to both the reinforcement and the agent as determined form the damp factor in DMA analysis. On the other hand, forecasting the variation of this parameter (T_g) as a function of both the interfacial agent and reinforcement content. For such purposes, and by assuming the complex character of the iPP/aPP-pPBMA/Mica system, wherein interaction between the components will define the final behaviour, a Box–Wilson experimental design considering the amount of mica particles and of interface agent as the independent variables, and the T_g as the dependent one, has been used. By taking in mind that the glass transition is a design threshold for the ultimate properties of parts based in this type of organic–inorganic hybrid materials, the final purpose of the work is the prediction and interpretation of the effect of both variables on this key parameter. Full article

(This article belongs to the Special Issue Organic-Inorganic Hybrid Materials)

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19 pages, 3623 KiB

Open AccessArticle

Effect of Chlorophyll Hybrid Nanopigments from Broccoli Waste on Thermomechanical and Colour Behaviour of Polyester-Based Bionanocomposites

by Bàrbara Micó-Vicent, Marina Ramos, Francesca Luzi, Franco Dominici, Valentín Viqueira, Luigi Torre, Alfonso Jiménez, Debora Puglia and María Carmen Garrigós

Polymers 2020, 12(11), 2508; https://doi.org/10.3390/polym12112508 - 28 Oct 2020

Cited by 10 | Viewed by 2989

Abstract

Natural dyes obtained from agro-food waste can be considered promising substitutes of synthetic dyes to be used in several applications. With this aim, in the present work, we studied the use of chlorophyll dye (CD) extracted from broccoli waste to obtain hybrid nanopigments [...] Read more.

Natural dyes obtained from agro-food waste can be considered promising substitutes of synthetic dyes to be used in several applications. With this aim, in the present work, we studied the use of chlorophyll dye (CD) extracted from broccoli waste to obtain hybrid nanopigments based on calcined hydrotalcite (HT) and montmorillonite (MMT) nanoclays. The synthesized chlorophyll hybrid nanopigments (CDNPs), optimized by using statistical designed experiments, were melt-extruded with a polyester-based matrix (INZEA) at 7 wt% loading. Mechanical, thermal, structural, morphological and colour properties of the obtained bionanocomposites were evaluated. The obtained results evidenced that the maximum CD adsorption into HT was obtained when adding 5 wt% of surfactant (sodium dodecyl sulphate) without using any biomordant and coupling agent, while the optimal conditions for MMT were achieved without adding any of the studied modifiers. In both cases, an improvement in CD thermal stability was observed by its incorporation in the nanoclays, able to protect chlorophyll degradation. The addition of MMT to INZEA resulted in large ΔE* values compared to HT incorporation, showing bionanocomposite green/yellow tones as a consequence of the CDNPs addition. The results obtained by XRD and TEM revealed a partially intercalated/exfoliated structure for INZEA-based bionanocomposites, due to the presence of an inorganic filler in the formulation of the commercial product, which was also confirmed by TGA analysis. CDNPs showed a reinforcement effect due to the presence of the hybrid nanopigments and up to 26% improvement in Young’s modulus compared to neat INZEA. Finally, the incorporation of CDNPs induced a decrease in thermal stability as well as limited effect in the melting/crystallization behaviour of the INZEA matrix. The obtained results showed the potential use of green natural dyes from broccoli wastes, adsorbed into nanoclays, for the development of naturally coloured bionanocomposites. Full article

(This article belongs to the Special Issue Organic-Inorganic Hybrid Materials)

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15 pages, 6401 KiB

Open AccessArticle

Performance of Nano- and Microcalcium Carbonate in Uncrosslinked Natural Rubber Composites: New Results of Structure–Properties Relationship

by Nantikan Phuhiangpa, Worachai Ponloa, Saree Phongphanphanee and Wirasak Smitthipong

Polymers 2020, 12(9), 2002; https://doi.org/10.3390/polym12092002 - 03 Sep 2020

Cited by 23 | Viewed by 3024

Abstract

Calcium carbonate (CaCO₃) is one of the most important inorganic powders and is widely used as filler in order to reduce costs in the rubber industry. Nanocalcium carbonate reduces costs and acts as a semireinforcing filler that improves the mechanical properties [...] Read more.

Calcium carbonate (CaCO₃) is one of the most important inorganic powders and is widely used as filler in order to reduce costs in the rubber industry. Nanocalcium carbonate reduces costs and acts as a semireinforcing filler that improves the mechanical properties of rubber composites. The objective of this study was to investigate the effect of nano-CaCO₃ (NCC) and micro-CaCO₃ (MCC) on the properties of natural rubber composites, in particular, new results of structure–properties relationship. The effects of NCC/MCC on the properties of rubber composites, such as Mooney viscosity, bound rubber, Mullins effect, and Payne effect, were investigated. The result of the Mullins effect of rubber composites filled with NCC was in good agreement with the results of Mooney viscosity and bound rubber, with higher Mooney viscosity and bound rubber leading to higher stress to pull the rubber composites. The Payne effect showed that the value of different storage moduli (ΔG’) of rubber composites filled with 25 parts per hundred rubber (phr) NCC was the lowest due to weaker filler network, while the rubber supplemented with 100 phr NCC had more significant ΔG’ values with increase in strain. The results of rubber composites filled with MCC showed the same tendency as those of rubber composites filled with NCC. However, the effect of specific surface area of NCC on the properties of rubber composites was more pronounced than those of rubber composites filled with MCC. Finite element analysis of the mechanical property of rubber composites was in good agreement with the result from the experiment. The master curves of time–temperature superposition presented lower free volume in the composites for higher loading of filler, which would require more relaxation time of rubber molecules. This type of nanocalcium carbonate material can be applied to tailor the properties and processability of rubber products. Full article

(This article belongs to the Special Issue Organic-Inorganic Hybrid Materials)

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11 pages, 1679 KiB

Open AccessArticle

Rheological, Mechanical and Morphological Characterization of Fillers in the Nautical Field: The Role of Dispersing Agents on Composite Materials

by Silvia Vita, Rico Ricotti, Andrea Dodero, Silvia Vicini, Per Borchardt, Emiliano Pinori and Maila Castellano

Polymers 2020, 12(6), 1339; https://doi.org/10.3390/polym12061339 - 12 Jun 2020

Cited by 4 | Viewed by 2572

Abstract

Coatings have a fundamental role in covering the external surface of yachts by acting both as protective and aesthetic layers. In particular, fillers represent the essential layer from the point of view of mechanical properties and consist of a polymeric matrix, different extenders [...] Read more.

Coatings have a fundamental role in covering the external surface of yachts by acting both as protective and aesthetic layers. In particular, fillers represent the essential layer from the point of view of mechanical properties and consist of a polymeric matrix, different extenders and additives, and dispersing agents, with the latter having the role to provide good extender-matrix compatibility. In the present work, the effects of dispersing agents with an ionic or steric action on the interactions between hollow glass microspheres and an epoxy-polyamide resin are evaluated. Un-crosslinked filler materials are studied via rheological tests, whereas the mechanical and morphological properties of the crosslinked samples are assessed. The results clearly indicate that steric dispersing agents provide a much greater compatibility effect compared to ionic ones, owing to their steric hindrance capability, thus leading to better-performing filler materials with a less-marked Payne effect, which is here proved to be an efficient tool to provide information concerning the extent of component interactions in nautical fillers. To the best of our knowledge, this work represents the first attempt to deeply understand the role of dispersing agents, which are until now empirically used in the preparation of fillers. Full article

(This article belongs to the Special Issue Organic-Inorganic Hybrid Materials)

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16 pages, 3384 KiB

Open AccessArticle

Organic and Inorganic PCL-Based Electrospun Fibers

by Adrián Leonés, Alicia Mujica-Garcia, Marina Patricia Arrieta, Valentina Salaris, Daniel Lopez, José Maria Kenny and Laura Peponi

Polymers 2020, 12(6), 1325; https://doi.org/10.3390/polym12061325 - 10 Jun 2020

Cited by 30 | Viewed by 4208

Abstract

In this work, different nanocomposite electrospun fiber mats were obtained based on poly(e-caprolactone) (PCL) and reinforced with both organic and inorganic nanoparticles. In particular, on one side, cellulose nanocrystals (CNC) were synthesized and functionalized by “grafting from” reaction, using their superficial [...] Read more.

In this work, different nanocomposite electrospun fiber mats were obtained based on poly(e-caprolactone) (PCL) and reinforced with both organic and inorganic nanoparticles. In particular, on one side, cellulose nanocrystals (CNC) were synthesized and functionalized by “grafting from” reaction, using their superficial OH– group to graft PCL chains. On the other side, commercial chitosan, graphene as organic, while silver, hydroxyapatite, and fumed silica nanoparticles were used as inorganic reinforcements. All the nanoparticles were added at 1 wt% with respect to the PCL polymeric matrix in order to compare the different behavior of the woven no-woven nanocomposite electrospun fibers with a fixed amount of both organic and inorganic nanoparticles. From the thermal point of view, no difference was found between the effect of the addition of organic or inorganic nanoparticles, with no significant variation in the T_g (glass transition temperature), T_m (melting temperature), and the degree of crystallinity, leading in all cases to high crystallinity electrospun mats. From the mechanical point of view, the highest values of Young modulus were obtained when graphene, CNC, and silver nanoparticles were added to the PCL electrospun fibers. Moreover, all the nanoparticles used, both organic and inorganic, increased the flexibility of the electrospun mats, increasing their elongation at break. Full article

(This article belongs to the Special Issue Organic-Inorganic Hybrid Materials)

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18 pages, 4760 KiB

Open AccessArticle

PDMS Based Hybrid Sol-Gel Materials for Sensing Applications in Alkaline Environments: Synthesis and Characterization

by Rui P. C. L. Sousa, Bárbara Ferreira, Miguel Azenha, Susana P. G. Costa, Carlos J. R. Silva and Rita B. Figueira

Polymers 2020, 12(2), 371; https://doi.org/10.3390/polym12020371 - 07 Feb 2020

Cited by 8 | Viewed by 4530

Abstract

Nowadays, concrete degradation is a major problem in the civil engineering field. Concrete carbonation, one of the main sources of structures’ degradation, causes concrete’s pH to decrease; hence, enabling the necessary conditions for corrosion reinforcement. An accurate, non-destructive sensor able to monitor the [...] Read more.

Nowadays, concrete degradation is a major problem in the civil engineering field. Concrete carbonation, one of the main sources of structures’ degradation, causes concrete’s pH to decrease; hence, enabling the necessary conditions for corrosion reinforcement. An accurate, non-destructive sensor able to monitor the pH decrease resistant to concrete conditions is envisaged by many researchers. Optical fibre sensors (OFS) are generally used for concrete applications due to their high sensitivity and resistance to external interferences. Organic-inorganic hybrid (OIH) films, for potential functionalization of OFS to be applied in concrete structures, were developed. Polydimethylsiloxane (PDMS) based sol-gel materials were synthesized by the formation of an amino alcohol precursor followed by hydrolysis and condensation. Different ratios between PDMS and (3-aminopropyl)triethoxysilane (3-APTES) were studied. The synthesized OIH films were characterized by Fourier-transformed infrared spectroscopy (FTIR), UV–Vis spectroscopy, electrochemical impedance spectroscopy (EIS) and thermogravimetric analysis (TGA). The OIH films were doped with phenolphthalein (Phph), a pH indicator, and were characterized by UV–Vis and EIS. FTIR characterization showed that the reaction between both precursors, the hydrolysis and the condensation reactions occurred successfully. UV–Vis characterization confirmed the presence of Phph embedded in the OIH matrices. Dielectric and thermal properties of the materials showed promising properties for application in contact with a high alkaline environment. Full article

(This article belongs to the Special Issue Organic-Inorganic Hybrid Materials)

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21 pages, 7908 KiB

Open AccessArticle

Variation of Ultimate Properties in Extruded iPP-Mesoporous Silica Nanocomposites by Effect of iPP Confinement within the Mesostructures

by Rosa Barranco-García, José M. Gómez-Elvira, Jorge A. Ressia, Lidia Quinzani, Enrique M. Vallés, Ernesto Pérez and María L. Cerrada

Polymers 2020, 12(1), 70; https://doi.org/10.3390/polym12010070 - 02 Jan 2020

Cited by 13 | Viewed by 1859

Abstract

Nanocomposites based on isotactic polypropylene (iPP) and mesoporous silica particles of either MCM-41 or SBA-15 were prepared by melt extrusion. The effect of the silica incorporated into an iPP matrix was firstly detected in the degradation behavior and in the rheological response of [...] Read more.

Nanocomposites based on isotactic polypropylene (iPP) and mesoporous silica particles of either MCM-41 or SBA-15 were prepared by melt extrusion. The effect of the silica incorporated into an iPP matrix was firstly detected in the degradation behavior and in the rheological response of the resultant composites. Both were ascribed, in principle, to variations in the inclusion of iPP chains within these two mesostructures, with well different pore size. DSC experiments did not provide information on the existence of confinement in the iPP-MCM-41 materials, whereas a small endotherm, located at about 100 °C and attributed to the melting of confined crystallites, is clearly observed in the iPP-SBA-15 composites. Real-time variable-temperature Small Angle X-ray Scattering (SAXS) experiments with synchrotron radiation turned out to be crucial to finding the presence of iPP within MCM-41 pores. From these measurements, precise information was also deduced on the influence of the MCM-41 on iPP long spacing since overlapping does not occur between most probable iPP long spacing peak with the characteristic diffractions from the MCM-41 hexagonal nanostructure in comparison with existing superposition in SBA-15-based materials. Full article

(This article belongs to the Special Issue Organic-Inorganic Hybrid Materials)

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17 pages, 8023 KiB

Open AccessArticle

Synergistic Effects of Two-Dimensional MXene and Ammonium Polyphosphate on Enhancing the Fire Safety of Polyvinyl Alcohol Composite Aerogels

by Xinxin Sheng, Sihao Li, Yanfeng Zhao, Dongsheng Zhai, Li Zhang and Xiang Lu

Polymers 2019, 11(12), 1964; https://doi.org/10.3390/polym11121964 - 29 Nov 2019

Cited by 47 | Viewed by 4655

Abstract

Fire and smoke suppressions of polyvinyl alcohol (PVA) aerogels are urgently required due to the serious fire hazard they present. MXene, a 2D transition-metal carbide with many excellent properties, is considered a promising synergist for providing excellent flame retardant performance. PVA/ammonium polyphosphate (APP)/transition [...] Read more.

Fire and smoke suppressions of polyvinyl alcohol (PVA) aerogels are urgently required due to the serious fire hazard they present. MXene, a 2D transition-metal carbide with many excellent properties, is considered a promising synergist for providing excellent flame retardant performance. PVA/ammonium polyphosphate (APP)/transition metal carbide (MXene) composite aerogels were prepared via the freeze-drying method to enhance the flame retardancy. Thermogravimetric analysis, limiting oxygen index, vertical burning, and cone calorimeter tests were executed to investigate the thermal stability and flame retardancy of PVA/APP/MXene (PAM) composite aerogels. The results demonstrated that MXene boosted the flame retardancy of PVA-APP, and that PAM-2 (with 2.0 wt% MXene loading) passed the V-0 rating, and reached a maximum LOI value of 42%; Moreover, MXene endowed the PVA-APP system with excellent fire and smoke suppression performance, as the the peak heat release rate and peak smoke production rate were significantly reduced by 55% and 74% at 1.0 wt% MXene loading. The flame retardant mechanism was systematically studied, MXene facilitated the generation of compact intumescent residues via ita catalyst effects, thus further restraining the release of heat and smoke. This work provides a simple route to improve the flame retardancy of PVA aerogels via the synergistic effect of MXene and APP. Full article

(This article belongs to the Special Issue Organic-Inorganic Hybrid Materials)

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9 pages, 2373 KiB

Open AccessArticle

Influence of Incorporated Polydimethylsiloxane on Properties of PA66 Fiber and Its Fabric Performance

by Wei Peng, Ying Qian, Tong Zhou, Shenglin Yang, Junhong Jin and Guang Li

Polymers 2019, 11(11), 1735; https://doi.org/10.3390/polym11111735 - 23 Oct 2019

Cited by 6 | Viewed by 2414

Abstract

Poly(hexamethyllene adipamide), PA66 fiber has played an important role in varied industrial applications, and its corresponding product would become more competitive if some extra value was added to PA66 fiber. In this article, polydimethylsiloxane (PDMS) was used as an additive to prepare PA66/PDMS [...] Read more.

Poly(hexamethyllene adipamide), PA66 fiber has played an important role in varied industrial applications, and its corresponding product would become more competitive if some extra value was added to PA66 fiber. In this article, polydimethylsiloxane (PDMS) was used as an additive to prepare PA66/PDMS blend fibers through melt blend spinning carried out by a screw extruder spinning machine. When the amount of incorporated PDMS was 0.5–3 wt %, the blend melt demonstrated good spinning ability, and the PA66/PDMS blend fibers exhibited excellent mechanical property and reduced hot shrinkage. Moreover, the crystallization and melting behavior of PA66 in the blend fibers turned out to be not affected by the existence of PDMS. In addition, the contact angle of water on the blend fiber surface became larger, while the value of friction coefficient on the surface of fibers got lower with increasing PDMS content in the blend fibers. After evaluating the fabric woven by PA66/PDMS blend fibers using the KES-F KES-FB-2 fabric measuring system, it was found that as PDMS content increased, the flexural rigidity and bending hysteresis would be lower, yet elasticity rate of compression work would be higher, which explained how the fabric composed of the blend fiber performed better in terms of softness and elasticity. Full article

(This article belongs to the Special Issue Organic-Inorganic Hybrid Materials)

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15 pages, 8026 KiB

Open AccessArticle

Thermo-Reversible Hybrid Gels Formed from the Combination of Isotactic Polystyrene and [Fe(II) (4-Octadecyl-1,2,4-Triazole)₃(ClO₄)₂]_n Metallo-Organic Polymer: Thermal and Viscoelastic Properties

by Coro Echeverría, Miguel Rubio and Daniel López

Polymers 2019, 11(6), 957; https://doi.org/10.3390/polym11060957 - 01 Jun 2019

Cited by 4 | Viewed by 2456

Abstract

Nano-sized one-dimensional metallo-organic polymers, characterized by the phenomenon of spin transition, are excellent candidates for advanced technological applications such as optical sensors, storage, and information processing devices. However, the main drawback of this type of polymers is their fragile mechanical properties, which hinders [...] Read more.

Nano-sized one-dimensional metallo-organic polymers, characterized by the phenomenon of spin transition, are excellent candidates for advanced technological applications such as optical sensors, storage, and information processing devices. However, the main drawback of this type of polymers is their fragile mechanical properties, which hinders its processing and handling, and makes their practical use unfeasible. To overcome this problem, in this work, hybrid thermo-reversible gels are synthesized by combination of a metallo-organic polymer and isotactic polystyrene (iPS) in cis-decaline. A detailed investigation of the thermal and viscoelastic properties of the hybrid gels, in terms of iPS and metallo-organic polymer concentration is performed by means of differential scanning calorimetry and oscillatory rheology, respectively. From the analysis of the thermal properties, three transitions have been determined upon heating: Monotectic transition of the iPS gel, melting of the iPS gel, and melting of the metal-organic polymer gel, which suggest that the gels of the two polymers are formed independently in the hybrid gel, as long as the two polymers are in concentrations above the corresponding critical gelation concentrations. Results regarding viscoelastic properties and morphology confirmed that hybrid gels consisted of an interpenetrated network of polymer gels, formed by iPS and metallo-organic poymer gels growing independently. Full article

(This article belongs to the Special Issue Organic-Inorganic Hybrid Materials)

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