Editorial

4 pages, 196 KiB

Open AccessEditorial

Polymeric Materials: Surfaces, Interfaces and Bioapplications

by Alexandra Muñoz-Bonilla, Coro Echeverría, Águeda Sonseca, Marina P. Arrieta and Marta Fernández-García

Materials 2019, 12(8), 1312; https://doi.org/10.3390/ma12081312 - 22 Apr 2019

Cited by 4 | Viewed by 2582

Abstract

This special issue “Polymeric Materials: Surfaces, Interfaces and Bioapplications” was proposed to cover all the aspects related to recent innovations on surfaces, interfaces and bioapplications of polymeric materials. The collected articles show the advances in polymeric materials, which have tremendous applications in agricultural [...] Read more.

This special issue “Polymeric Materials: Surfaces, Interfaces and Bioapplications” was proposed to cover all the aspects related to recent innovations on surfaces, interfaces and bioapplications of polymeric materials. The collected articles show the advances in polymeric materials, which have tremendous applications in agricultural films, food packaging, dental restoration, antimicrobial systems and tissue engineering. We hope that readers will be able to enjoy highly relevant topics that are related to polymers. Therefore, we hope to prove that plastics can be a solution and not a problem. Full article

(This article belongs to the Special Issue Polymeric Materials: Surfaces, Interfaces and Bioapplications)

Research

Jump to: Editorial, Review

17 pages, 4394 KiB

Open AccessArticle

Graphene Oxide Oxygen Content Affects Physical and Biological Properties of Scaffolds Based on Chitosan/Graphene Oxide Conjugates

by Iolanda Francolini, Elena Perugini, Ilaria Silvestro, Mariangela Lopreiato, Anna Scotto d’Abusco, Federica Valentini, Ernesto Placidi, Fabrizio Arciprete, Andrea Martinelli and Antonella Piozzi

Materials 2019, 12(7), 1142; https://doi.org/10.3390/ma12071142 - 08 Apr 2019

Cited by 27 | Viewed by 3799

Abstract

Tissue engineering is a highly interdisciplinary field of medicine aiming at regenerating damaged tissues by combining cells with porous scaffolds materials. Scaffolds are templates for tissue regeneration and should ensure suitable cell adhesion and mechanical stability throughout the application period. Chitosan (CS) is [...] Read more.

Tissue engineering is a highly interdisciplinary field of medicine aiming at regenerating damaged tissues by combining cells with porous scaffolds materials. Scaffolds are templates for tissue regeneration and should ensure suitable cell adhesion and mechanical stability throughout the application period. Chitosan (CS) is a biocompatible polymer highly investigated for scaffold preparation but suffers from poor mechanical strength. In this study, graphene oxide (GO) was conjugated to chitosan at two weight ratios 0.3% and 1%, and the resulting conjugates were used to prepare composite scaffolds with improved mechanical strength. To study the effect of GO oxidation degree on scaffold mechanical and biological properties, GO samples at two different oxygen contents were employed. The obtained GO/CS scaffolds were highly porous and showed good swelling in water, though to a lesser extent than pure CS scaffold. In contrast, GO increased scaffold thermal stability and mechanical strength with respect to pure CS, especially when the GO at low oxygen content was used. The scaffold in vitro cytocompatibility using human primary dermal fibroblasts was also affected by the type of used GO. Specifically, the GO with less content of oxygen provided the scaffold with the best biocompatibility. Full article

(This article belongs to the Special Issue Polymeric Materials: Surfaces, Interfaces and Bioapplications)

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13 pages, 3245 KiB

Open AccessArticle

The Effect of the Isomeric Chlorine Substitutions on the Honeycomb-Patterned Films of Poly(x-chlorostyrene)s/Polystyrene Blends and Copolymers via Static Breath Figure Technique

by Leire Ruiz-Rubio, Leyre Pérez-Álvarez, Julia Sanchez-Bodón, Valeria Arrighi and José Luis Vilas-Vilela

Materials 2019, 12(1), 167; https://doi.org/10.3390/ma12010167 - 07 Jan 2019

Cited by 2 | Viewed by 3481

Abstract

Polymeric thin films patterned with honeycomb structures were prepared from poly(x-chlorostyrene) and statistical poly(x-chlorostyrene-co-styrene) copolymers by static breath figure method. Each polymeric sample was synthesized by free radical polymerization and its solution in tetrahydrofuran cast on glass wafers under 90% relative humidity (RH). [...] Read more.

Polymeric thin films patterned with honeycomb structures were prepared from poly(x-chlorostyrene) and statistical poly(x-chlorostyrene-co-styrene) copolymers by static breath figure method. Each polymeric sample was synthesized by free radical polymerization and its solution in tetrahydrofuran cast on glass wafers under 90% relative humidity (RH). The effect of the chorine substitution in the topography and conformational entropy was evaluated. The entropy of each sample was calculated by using Voronoi tessellation. The obtained results revealed that these materials could be a suitable toolbox to develop a honeycomb patterns with a wide range of pore sizes for a potential use in contact guidance induced culture. Full article

(This article belongs to the Special Issue Polymeric Materials: Surfaces, Interfaces and Bioapplications)

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11 pages, 7562 KiB

Open AccessArticle

Creation of Superhydrophobic and Superhydrophilic Surfaces on ABS Employing a Nanosecond Laser

by Cristian Lavieja, Luis Oriol and José-Ignacio Peña

Materials 2018, 11(12), 2547; https://doi.org/10.3390/ma11122547 - 14 Dec 2018

Cited by 11 | Viewed by 2998

Abstract

A nanosecond green laser was employed to obtain both superhydrophobic and superhydrophilic surfaces on a white commercial acrylonitrile-butadiene-styrene copolymer (ABS). These wetting behaviors were directly related to a laser-induced superficial modification. A predefined pattern was not produced by the laser, rather, the entire [...] Read more.

A nanosecond green laser was employed to obtain both superhydrophobic and superhydrophilic surfaces on a white commercial acrylonitrile-butadiene-styrene copolymer (ABS). These wetting behaviors were directly related to a laser-induced superficial modification. A predefined pattern was not produced by the laser, rather, the entire surface was covered with laser pulses at 1200 DPI by placing the sample at different positions along the focal axis. The changes were related to the laser fluence used in each case. The highest fluence, on the focal position, induced a drastic heating of the material surface, and this enabled the melted material to flow, thus leading to an almost flat superhydrophilic surface. By contrast, the use of a lower fluence by placing the sample 0.8 µm out of the focal position led to a poor material flow and a fast cooling that froze in a rugged superhydrophobic surface. Contact angles higher than 150° and roll angles of less than 10° were obtained. These wetting behaviors were stable over time. Full article

(This article belongs to the Special Issue Polymeric Materials: Surfaces, Interfaces and Bioapplications)

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11 pages, 3078 KiB

Open AccessArticle

Composite Film Based on Pulping Industry Waste and Chitosan for Food Packaging

by Ji-Dong Xu, Ya-Shuai Niu, Pan-Pan Yue, Ya-Jie Hu, Jing Bian, Ming-Fei Li, Feng Peng and Run-Cang Sun

Materials 2018, 11(11), 2264; https://doi.org/10.3390/ma11112264 - 13 Nov 2018

Cited by 10 | Viewed by 3862

Abstract

Wood auto-hydrolysates (WAH) are obtained in the pulping process by the hydrothermal extraction, which contains lots of hemicelluloses and slight lignin. WAH and chitosan (CS) were introduced into this study to construct WAH-based films by the casting method. The FT-IR results revealed the [...] Read more.

Wood auto-hydrolysates (WAH) are obtained in the pulping process by the hydrothermal extraction, which contains lots of hemicelluloses and slight lignin. WAH and chitosan (CS) were introduced into this study to construct WAH-based films by the casting method. The FT-IR results revealed the crosslinking interaction between WAH and CS due to the Millard reaction. The morphology, transmittance, thermal properties and mechanical properties of composite WAH/CS films were investigated. As the results showed, the tensile strength, light transmittances and thermal stability of the WAH-based composite films increased with the increment of WAH/CS content ratio. In addition, the results of oxygen transfer rate (OTR) and water vapor permeability (WVP) suggested that the OTR and WVP values of the films decreased due to the addition of CS. The maximum value of tensile strengths of the composite films achieved 71.2 MPa and the OTR of the films was low as 0.16 cm³·μm·m⁻²·24 h⁻¹·kPa⁻¹, these properties are better than those of other hemicelluloses composite films. These results suggested that the barrier composite films based on WAH and CS will become attractive in the food packaging application for great mechanical properties, good transmittance and low oxygen transfer rate. Full article

(This article belongs to the Special Issue Polymeric Materials: Surfaces, Interfaces and Bioapplications)

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18 pages, 4373 KiB

Open AccessArticle

Interference of Biodegradable Plastics in the Polypropylene Recycling Process

by María Dolores Samper, David Bertomeu, Marina Patricia Arrieta, José Miguel Ferri and Juan López-Martínez

Materials 2018, 11(10), 1886; https://doi.org/10.3390/ma11101886 - 02 Oct 2018

Cited by 53 | Viewed by 7338

Abstract

Recycling polymers is common due to the need to reduce the environmental impact of these materials. Polypropylene (PP) is one of the polymers called ‘commodities polymers’ and it is commonly used in a wide variety of short-term applications such as food packaging and [...] Read more.

Recycling polymers is common due to the need to reduce the environmental impact of these materials. Polypropylene (PP) is one of the polymers called ‘commodities polymers’ and it is commonly used in a wide variety of short-term applications such as food packaging and agricultural products. That is why a large amount of PP residues that can be recycled are generated every year. However, the current increasing introduction of biodegradable polymers in the food packaging industry can negatively affect the properties of recycled PP if those kinds of plastics are disposed with traditional plastics. For this reason, the influence that generates small amounts of biodegradable polymers such as polylactic acid (PLA), polyhydroxybutyrate (PHB) and thermoplastic starch (TPS) in the recycled PP were analyzed in this work. Thus, recycled PP was blended with biodegradables polymers by melt extrusion followed by injection moulding process to simulate the industrial conditions. Then, the obtained materials were evaluated by studding the changes on the thermal and mechanical performance. The results revealed that the vicat softening temperature is negatively affected by the presence of biodegradable polymers in recycled PP. Meanwhile, the melt flow index was negatively affected for PLA and PHB added blends. The mechanical properties were affected when more than 5 wt.% of biodegradable polymers were present. Moreover, structural changes were detected when biodegradable polymers were added to the recycled PP by means of FTIR, because of the characteristic bands of the carbonyl group (between the band 1700–1800 cm⁻¹) appeared due to the presence of PLA, PHB or TPS. Thus, low amounts (lower than 5 wt.%) of biodegradable polymers can be introduced in the recycled PP process without affecting the overall performance of the final material intended for several applications, such as food packaging, agricultural films for farming and crop protection. Full article

(This article belongs to the Special Issue Polymeric Materials: Surfaces, Interfaces and Bioapplications)

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8 pages, 2765 KiB

Open AccessArticle

Ring Wrinkle Patterns with Continuously Changing Wavelength Produced Using a Controlled-Gradient Light Field

by Hongye Li, Bin Sheng, He Wu, Yuanshen Huang, Dawei Zhang and Songlin Zhuang

Materials 2018, 11(9), 1571; https://doi.org/10.3390/ma11091571 - 01 Sep 2018

Cited by 7 | Viewed by 3452

Abstract

We report a facile method to prepare gradient wrinkles using a controlled-gradient light field. Because of the gradient distance between the ultraviolet (UV) lamp and polydimethylsiloxane (PDMS) substrate during UV/ozone treatment, the irradiance reaching the substrate continuously changed, which was transferred into the [...] Read more.

We report a facile method to prepare gradient wrinkles using a controlled-gradient light field. Because of the gradient distance between the ultraviolet (UV) lamp and polydimethylsiloxane (PDMS) substrate during UV/ozone treatment, the irradiance reaching the substrate continuously changed, which was transferred into the resulting SiO_x film with a varying thickness. Therefore, wrinkles with continuously changing wavelength were fabricated using this approach. It was found that the wrinkle wavelength decreased as the distance increased. We fabricated 1-D wrinkle patterns and ring wrinkles with a gradient wavelength. The ring wrinkles were prepared using radial stresses, which were achieved by pulling the center of a freely hanging PDMS film. The resulting wrinkles with changing wavelength can be used in fluid handling systems, biological templates, and optical devices. Full article

(This article belongs to the Special Issue Polymeric Materials: Surfaces, Interfaces and Bioapplications)

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14 pages, 2881 KiB

Open AccessArticle

Calcium Chloride Modified Alginate Microparticles Formulated by the Spray Drying Process: A Strategy to Prolong the Release of Freely Soluble Drugs

by Marta Szekalska, Katarzyna Sosnowska, Anna Czajkowska-Kośnik and Katarzyna Winnicka

Materials 2018, 11(9), 1522; https://doi.org/10.3390/ma11091522 - 24 Aug 2018

Cited by 43 | Viewed by 4533

Abstract

Alginate (ALG) cross-linking by CaCl₂ is a promising strategy to obtain modified-release drug delivery systems with mucoadhesive properties. However, current technologies to produce CaCl₂ cross-linked alginate microparticles possess major disadvantages, such as a poor encapsulation efficiency of water-soluble drugs and a [...] Read more.

Alginate (ALG) cross-linking by CaCl₂ is a promising strategy to obtain modified-release drug delivery systems with mucoadhesive properties. However, current technologies to produce CaCl₂ cross-linked alginate microparticles possess major disadvantages, such as a poor encapsulation efficiency of water-soluble drugs and a difficulty in controlling the process. Hence, this study presents a novel method that streamlines microparticle production by spray drying; a rapid, continuous, reproducible, and scalable technique enabling obtainment of a product with low moisture content, high drug loading, and a high production yield. To model a freely water-soluble drug, metformin hydrochloride (MF) was selected. It was observed that MF was successfully encapsulated in alginate microparticles cross-linked by CaCl₂ using a one-step drying process. Modification of ALG provided drug release prolongation—particles obtained from 2% ALG cross-linked by 0.1% CaCl₂ with a prolonged MF rate of dissolution of up to 12 h. Cross-linking of the ALG microparticles structure by CaCl₂ decreased the swelling ratio and improved the mucoadhesive properties which were evaluated using porcine stomach mucosa. Full article

(This article belongs to the Special Issue Polymeric Materials: Surfaces, Interfaces and Bioapplications)

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15 pages, 2421 KiB

Open AccessArticle

Surface-Attached Poly(oxanorbornene) Hydrogels with Antimicrobial and Protein-Repellent Moieties: The Quest for Simultaneous Dual Activity

by Monika Kurowska, Vania Tanda Widyaya, Ali Al-Ahmad and Karen Lienkamp

Materials 2018, 11(8), 1411; https://doi.org/10.3390/ma11081411 - 11 Aug 2018

Cited by 9 | Viewed by 3162

Abstract

By copolymerizing an amphiphilic oxanorbornene monomer bearing N- tert-butyloxycarbonyl (Boc) protected cationic groups with an oxanorbornene-functionalized poly(ethylene glycol) (PEG) macromonomer, bifunctional comb copolymers were obtained. Varying the comonomer ratios led to copolymers with PEG contents between 5–25 mol %. These polymers were simultaneously [...] Read more.

By copolymerizing an amphiphilic oxanorbornene monomer bearing N- tert-butyloxycarbonyl (Boc) protected cationic groups with an oxanorbornene-functionalized poly(ethylene glycol) (PEG) macromonomer, bifunctional comb copolymers were obtained. Varying the comonomer ratios led to copolymers with PEG contents between 5–25 mol %. These polymers were simultaneously surface-immobilized on benzophenone-bearing substrates and cross-linked with pentaerythritoltetrakis(3-mercaptopropionate). They were then immersed into HCl to remove the Boc groups. The thus obtained surface-attached polymer hydrogels (called SMAMP*-co-PEG) were simultaneously antimicrobial and protein-repellent. Physical characterization data showed that the substrates used were homogeneously covered with the SMAMP*-co-PEG polymer, and that the PEG moieties tended to segregate to the polymer–air interface. Thus, with increasing PEG content, the interface became increasingly hydrophilic and protein-repellent, as demonstrated by a protein adhesion assay. With 25 mol % PEG, near-quantitative protein-adhesion was observed. The antimicrobial activity of the SMAMP*-co-PEG polymers originates from the electrostatic interaction of the cationic groups with the negatively charged cell envelope of the bacteria. However, the SMAMP*-co-PEG surfaces were only fully active against E. coli, while their activity against S. aureus was already compromised by as little as 5 mol % (18.8 mass %) PEG. The long PEG chains seem to prevent the close interaction of bacteria with the surface, and also might reduce the surface charge density. Full article

(This article belongs to the Special Issue Polymeric Materials: Surfaces, Interfaces and Bioapplications)

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10 pages, 3007 KiB

Open AccessArticle

Antimicrobial Porous Surfaces Prepared by Breath Figures Approach

by Alexandra Muñoz-Bonilla, Rocío Cuervo-Rodríguez, Fátima López-Fabal, José L. Gómez-Garcés and Marta Fernández-García

Materials 2018, 11(8), 1266; https://doi.org/10.3390/ma11081266 - 24 Jul 2018

Cited by 16 | Viewed by 3140

Abstract

Herein, efficient antimicrobial porous surfaces were prepared by breath figures approach from polymer solutions containing low content of block copolymers with high positive charge density. In brief, those block copolymers, which were used as additives, are composed of a polystyrene segment and a [...] Read more.

Herein, efficient antimicrobial porous surfaces were prepared by breath figures approach from polymer solutions containing low content of block copolymers with high positive charge density. In brief, those block copolymers, which were used as additives, are composed of a polystyrene segment and a large antimicrobial block bearing flexible side chain with 1,3-thiazolium and 1,2,3-triazolium groups, PS₅₄-b-PTTBM-M₄₄, PS₅₄-b-PTTBM-B₄₄, having different alkyl groups, methyl or butyl, respectively. The antimicrobial block copolymers were blended with commercial polystyrene in very low proportions, from 3 to 9 wt %, and solubilized in THF. From these solutions, ordered porous films functionalized with antimicrobial cationic copolymers were fabricated, and the influence of alkylating agent and the amount of copolymer in the blend was investigated. Narrow pore size distribution was obtained for all the samples with pore diameters between 5 and 11 µm. The size of the pore decreased as the hydrophilicity of the system increased; thus, either as the content of copolymer was augmented in the blend or as the copolymers were quaternized with methyl iodide. The resulting porous polystyrene surfaces functionalized with low content of antimicrobial copolymers exhibited remarkable antibacterial efficiencies against Gram positive bacteria Staphylococcus aureus, and Candida parapsilosis fungi as microbial models. Full article

(This article belongs to the Special Issue Polymeric Materials: Surfaces, Interfaces and Bioapplications)

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12 pages, 2665 KiB

Open AccessArticle

Effect of CNT/PDMS Nanocomposites on the Dynamics of Pioneer Bacterial Communities in the Natural Biofilms of Seawater

by Yubin Ji, Yuan Sun, Yanhe Lang, Lei Wang, Bing Liu and Zhizhou Zhang

Materials 2018, 11(6), 902; https://doi.org/10.3390/ma11060902 - 28 May 2018

Cited by 17 | Viewed by 3129

Abstract

In this study, the antifouling (AF) performance of different carbon nanotubes (CNTs)-modified polydimethylsiloxane (PDMS) nanocomposites (PCs) was examined directly in the natural seawater, and further analyzed using the Multidimensional Scale Analyses (MDS) method. The early-adherent bacterial communities in the natural biofilms adhering to [...] Read more.

In this study, the antifouling (AF) performance of different carbon nanotubes (CNTs)-modified polydimethylsiloxane (PDMS) nanocomposites (PCs) was examined directly in the natural seawater, and further analyzed using the Multidimensional Scale Analyses (MDS) method. The early-adherent bacterial communities in the natural biofilms adhering to different PC surfaces were investigated using the single-stranded conformation polymorphism (SSCP) technique. The PCs demonstrated differences and reinforced AF properties in the field, and they were prone to clustering according to the discrepancies within different CNT fillers. Furthermore, most PC surfaces only demonstrated weak modulating effects on the biological colonization and successional process of the early bacterial communities in natural biofilms, indicating that the presence of the early colonized prokaryotic microbes would be one of the primary causes of colonization and deterioration of the PCs. C6 coating seems to be promising for marine AF applications, since it has a strong perturbation effect on pioneer prokaryotic colonization. Full article

(This article belongs to the Special Issue Polymeric Materials: Surfaces, Interfaces and Bioapplications)

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14 pages, 6477 KiB

Open AccessArticle

The Evaluation of Physio-Mechanical and Tribological Characterization of Friction Composites Reinforced by Waste Corn Stalk

by Yunhai Ma, Siyang Wu, Jian Zhuang, Jin Tong, Yang Xiao and Hongyan Qi

Materials 2018, 11(6), 901; https://doi.org/10.3390/ma11060901 - 27 May 2018

Cited by 30 | Viewed by 3845

Abstract

This paper addressed the potential use of fibers from waste corn stalk as reinforcing materials in friction composites. The friction composites with different contents of corn stalk fibers were prepared, and their tribological and physio-mechanical behaviors were characterized. It was found that the [...] Read more.

This paper addressed the potential use of fibers from waste corn stalk as reinforcing materials in friction composites. The friction composites with different contents of corn stalk fibers were prepared, and their tribological and physio-mechanical behaviors were characterized. It was found that the incorporation of corn stalk fibers had a positive effect on the friction coefficients and wear rates of friction composites. Based on comparisons of the overall performance, FC-6 (containing 6 wt % corn stalk fibers) was selected as the best performing specimen. The fade ratio of specimen FC-6 was 7.8% and its recovery ratio was 106.5%, indicating excellent fade resistance and recovery behaviors. The wear rate of specimen FC-6 was the lowest (0.427 × 10⁻⁷ mm³ (N·mm)⁻¹ at 350 °C) among all tested composites. Furthermore, worn surface morphology was characterized by scanning electron microscopy and confocal laser scanning microscopy. The results revealed that the satisfactory wear resistance performances were associated with the secondary plateaus formed on the worn surfaces. This research was contributive to the environmentally-friendly application of waste corn stalk. Full article

(This article belongs to the Special Issue Polymeric Materials: Surfaces, Interfaces and Bioapplications)

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Review

Jump to: Editorial, Research

52 pages, 7103 KiB

Open AccessFeature PaperReview

Bio-Based Polymers with Antimicrobial Properties towards Sustainable Development

by Alexandra Muñoz-Bonilla, Coro Echeverria, Águeda Sonseca, Marina P. Arrieta and Marta Fernández-García

Materials 2019, 12(4), 641; https://doi.org/10.3390/ma12040641 - 20 Feb 2019

Cited by 122 | Viewed by 10418

Abstract

This article concisely reviews the most recent contributions to the development of sustainable bio-based polymers with antimicrobial properties. This is because some of the main problems that humanity faces, nowadays and in the future, are climate change and bacterial multi-resistance. Therefore, scientists are [...] Read more.

This article concisely reviews the most recent contributions to the development of sustainable bio-based polymers with antimicrobial properties. This is because some of the main problems that humanity faces, nowadays and in the future, are climate change and bacterial multi-resistance. Therefore, scientists are trying to provide solutions to these problems. In an attempt to organize these antimicrobial sustainable materials, we have classified them into the main families; i.e., polysaccharides, proteins/polypeptides, polyesters, and polyurethanes. The review then summarizes the most recent antimicrobial aspects of these sustainable materials with antimicrobial performance considering their main potential applications in the biomedical field and in the food industry. Furthermore, their use in other fields, such as water purification and coating technology, is also described. Finally, some concluding remarks will point out the promise of this theme. Full article

(This article belongs to the Special Issue Polymeric Materials: Surfaces, Interfaces and Bioapplications)

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49 pages, 9122 KiB

Open AccessReview

Bio- and Fossil-Based Polymeric Blends and Nanocomposites for Packaging: Structure–Property Relationship

by Francesca Luzi, Luigi Torre, José Maria Kenny and Debora Puglia

Materials 2019, 12(3), 471; https://doi.org/10.3390/ma12030471 - 03 Feb 2019

Cited by 119 | Viewed by 10156

Abstract

In the present review, the possibilities for blending of commodities and bio-based and/or biodegradable polymers for packaging purposes has been considered, limiting the analysis to this class of materials without considering blends where both components have a bio-based composition or origin. The production [...] Read more.

In the present review, the possibilities for blending of commodities and bio-based and/or biodegradable polymers for packaging purposes has been considered, limiting the analysis to this class of materials without considering blends where both components have a bio-based composition or origin. The production of blends with synthetic polymeric materials is among the strategies to modulate the main characteristics of biodegradable polymeric materials, altering disintegrability rates and decreasing the final cost of different products. Special emphasis has been given to blends functional behavior in the frame of packaging application (compostability, gas/water/light barrier properties, migration, antioxidant performance). In addition, to better analyze the presence of nanosized ingredients on the overall behavior of a nanocomposite system composed of synthetic polymers, combined with biodegradable and/or bio-based plastics, the nature and effect of the inclusion of bio-based nanofillers has been investigated. Full article

(This article belongs to the Special Issue Polymeric Materials: Surfaces, Interfaces and Bioapplications)

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24 pages, 1911 KiB

Open AccessFeature PaperReview

Electroactive Smart Polymers for Biomedical Applications

by Humberto Palza, Paula Andrea Zapata and Carolina Angulo-Pineda

Materials 2019, 12(2), 277; https://doi.org/10.3390/ma12020277 - 16 Jan 2019

Cited by 131 | Viewed by 11705

Abstract

The flexibility in polymer properties has allowed the development of a broad range of materials with electroactivity, such as intrinsically conductive conjugated polymers, percolated conductive composites, and ionic conductive hydrogels. These smart electroactive polymers can be designed to respond rationally under an electric [...] Read more.

The flexibility in polymer properties has allowed the development of a broad range of materials with electroactivity, such as intrinsically conductive conjugated polymers, percolated conductive composites, and ionic conductive hydrogels. These smart electroactive polymers can be designed to respond rationally under an electric stimulus, triggering outstanding properties suitable for biomedical applications. This review presents a general overview of the potential applications of these electroactive smart polymers in the field of tissue engineering and biomaterials. In particular, details about the ability of these electroactive polymers to: (1) stimulate cells in the context of tissue engineering by providing electrical current; (2) mimic muscles by converting electric energy into mechanical energy through an electromechanical response; (3) deliver drugs by changing their internal configuration under an electrical stimulus; and (4) have antimicrobial behavior due to the conduction of electricity, are discussed. Full article

(This article belongs to the Special Issue Polymeric Materials: Surfaces, Interfaces and Bioapplications)

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41 pages, 5027 KiB

Open AccessReview

Materials for the Spine: Anatomy, Problems, and Solutions

by Brody A. Frost, Sandra Camarero-Espinosa and E. Johan Foster

Materials 2019, 12(2), 253; https://doi.org/10.3390/ma12020253 - 14 Jan 2019

Cited by 77 | Viewed by 34915

Abstract

Disc degeneration affects 12% to 35% of a given population, based on genetics, age, gender, and other environmental factors, and usually occurs in the lumbar spine due to heavier loads and more strenuous motions. Degeneration of the extracellular matrix (ECM) within reduces mechanical [...] Read more.

Disc degeneration affects 12% to 35% of a given population, based on genetics, age, gender, and other environmental factors, and usually occurs in the lumbar spine due to heavier loads and more strenuous motions. Degeneration of the extracellular matrix (ECM) within reduces mechanical integrity, shock absorption, and swelling capabilities of the intervertebral disc. When severe enough, the disc can bulge and eventually herniate, leading to pressure build up on the spinal cord. This can cause immense lower back pain in individuals, leading to total medical costs exceeding $100 billion. Current treatment options include both invasive and noninvasive methods, with spinal fusion surgery and total disc replacement (TDR) being the most common invasive procedures. Although these treatments cause pain relief for the majority of patients, multiple challenges arise for each. Therefore, newer tissue engineering methods are being researched to solve the ever-growing problem. This review spans the anatomy of the spine, with an emphasis on the functions and biological aspects of the intervertebral discs, as well as the problems, associated solutions, and future research in the field. Full article

(This article belongs to the Special Issue Polymeric Materials: Surfaces, Interfaces and Bioapplications)

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17 pages, 2447 KiB

Open AccessReview

Developing a New Generation of Therapeutic Dental Polymers to Inhibit Oral Biofilms and Protect Teeth

by Ke Zhang, Bashayer Baras, Christopher D. Lynch, Michael D. Weir, Mary Anne S. Melo, Yuncong Li, Mark A. Reynolds, Yuxing Bai, Lin Wang, Suping Wang and Hockin H. K. Xu

Materials 2018, 11(9), 1747; https://doi.org/10.3390/ma11091747 - 17 Sep 2018

Cited by 17 | Viewed by 4564

Abstract

Polymeric tooth-colored restorations are increasingly popular in dentistry. However, restoration failures remain a major challenge, and more than 50% of all operative work was devoted to removing and replacing the failed restorations. This is a heavy burden, with the expense for restoring dental [...] Read more.

Polymeric tooth-colored restorations are increasingly popular in dentistry. However, restoration failures remain a major challenge, and more than 50% of all operative work was devoted to removing and replacing the failed restorations. This is a heavy burden, with the expense for restoring dental cavities in the U.S. exceeding $46 billion annually. In addition, the need is increasing dramatically as the population ages with increasing tooth retention in seniors. Traditional materials for cavity restorations are usually bioinert and replace the decayed tooth volumes. This article reviews cutting-edge research on the synthesis and evaluation of a new generation of bioactive dental polymers that not only restore the decayed tooth structures, but also have therapeutic functions. These materials include polymeric composites and bonding agents for tooth cavity restorations that inhibit saliva-based microcosm biofilms, bioactive resins for tooth root caries treatments, polymers that can suppress periodontal pathogens, and root canal sealers that can kill endodontic biofilms. These novel compositions substantially inhibit biofilm growth, greatly reduce acid production and polysaccharide synthesis of biofilms, and reduce biofilm colony-forming units by three to four orders of magnitude. This new class of bioactive and therapeutic polymeric materials is promising to inhibit tooth decay, suppress recurrent caries, control oral biofilms and acid production, protect the periodontium, and heal endodontic infections. Full article

(This article belongs to the Special Issue Polymeric Materials: Surfaces, Interfaces and Bioapplications)

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