Polymers

Research

Jump to: Review

1718 KiB

Open AccessArticle

Synthesis and Nanoprecipitation of HEMA-CL_n Based Polymers for the Production of Biodegradable Nanoparticles

by Simone Gatti, Azzurra Agostini, Raffaele Ferrari and Davide Moscatelli

Polymers 2017, 9(9), 389; https://doi.org/10.3390/polym9090389 - 23 Aug 2017

Cited by 9 | Viewed by 6730

Abstract

The control over the size distribution and stability of polymeric nanoparticles (NPs) is crucial in many of their applications, especially in the biomedical field. These characteristics are typically influenced by the production method and the nature of the starting material. To investigate these [...] Read more.

The control over the size distribution and stability of polymeric nanoparticles (NPs) is crucial in many of their applications, especially in the biomedical field. These characteristics are typically influenced by the production method and the nature of the starting material. To investigate these aspects, the controlled radical polymerization of functionalized methacrylates constituted by 2-hydroxyethyl methacrylate (HEMA) functionalized with a controlled number of ε-caprolactone (CL) units (HEMA-CL_n), was carried out via reversible addition–fragmentation chain transfer polymerization (RAFT) in solution. The living reaction allows for good control over the molar mass of the final polymer with a low molar mass dispersity. The obtained polymer solutions were nanoprecipitated in order to produce NPs suitable for drug delivery applications with narrow particle size distribution and a wide size range (from 60 to 250 nm). The NP synthesis has been performed using a mixing device, in order to control the parameters involved in the nanoprecipitation process. As already seen for similar systems, the size of the produced NPs is a function of the polymer concentration during the nanoprecipitation process. Nevertheless, when the polymer concentration is kept constant, the NP size is influenced by the chemical structure of the polymer used, in terms of the presence of PEG (poly(ethylene glycol)), the degree of RAFT polymerization, and the length of the caprolactone side chain. These characteristics were also found to influence the stability and degradation properties of the produced NPs. Full article

(This article belongs to the Special Issue Biodegradable Polymers)

► Show Figures

Graphical abstract

1597 KiB

Open AccessArticle

The Significant Influence of Bacterial Reaction on Physico-Chemical Property Changes of Biodegradable Natural and Synthetic Polymers Using Escherichia coli

by Chankyu Kang, SamSoo Kim, SooJung Kim and Jae Woong Lee

Polymers 2017, 9(4), 121; https://doi.org/10.3390/polym9040121 - 25 Mar 2017

Cited by 7 | Viewed by 4943

Abstract

Escherichia coli (E. coli) was used to activate hydrolysis reaction along with biodegradation in natural and synthetic fibers to identify possibilities as alternative substitutes for textile wastes using chemical solutions and enzymes. To confirm the reaction between the bacterial infections of E. coli [...] Read more.

Escherichia coli (E. coli) was used to activate hydrolysis reaction along with biodegradation in natural and synthetic fibers to identify possibilities as alternative substitutes for textile wastes using chemical solutions and enzymes. To confirm the reaction between the bacterial infections of E. coli and the excessively abundant interstitial spaces of the fibers, various types of natural and synthetic fibers such as cotton, wool, polyethylene terephalate (PET), polyadmide (PA), polyethylene (PE), and polypropylene (PP) were used to confirm the physico-chemical reactions. Tensile strength analysis, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and contact angle analysis were used to determine the physico-chemical property changes of the fiber by the bacteria. When biofilm was formed on the fiber surface, various physical changes such as the following were observed: (i) in the analysis of tensile strength, all except PA and PP were decreased and a decrease in cotton fibers was noticeable (ii) depending on the type of fibers, the degree of roughness was different, but generally the surface became rough. In this study, the change of roughness was the most severe on the cotton fiber surface and the change of PET and PA fiber was relatively small. It was found that the intensity peak of oxygen was increased, except for the in cases of PA and PP, through the change of chemical properties by XPS analysis. Changes in topographical properties on the surface through contact angle analysis were stronger in hydrophilic properties, and in the case of cotton, completely hydrophilic surfaces were formed. Through this study, PA and PP fibers, which are Olefin fibers, were theoretically free of physicochemical and topographical changes since there were no functional groups that could trigger the hydrolysis reaction. Full article

(This article belongs to the Special Issue Biodegradable Polymers)

► Show Figures

Figure 1

3564 KiB

Open AccessArticle

Reaction-Multi Diffusion Model for Nutrient Release and Autocatalytic Degradation of PLA-Coated Controlled-Release Fertilizer

by Sayed Ameenuddin Irfan, Radzuan Razali, KuZilati KuShaari and Nurlidia Mansor

Polymers 2017, 9(3), 111; https://doi.org/10.3390/polym9030111 - 22 Mar 2017

Cited by 10 | Viewed by 6584

Abstract

A mathematical model for the reaction-diffusion equation is developed to describe the nutrient release profiles and degradation of poly(lactic acid) (PLA)-coated controlled-release fertilizer. A multi-diffusion model that consists of coupled partial differential equations is used to study the diffusion and chemical reaction (autocatalytic [...] Read more.

A mathematical model for the reaction-diffusion equation is developed to describe the nutrient release profiles and degradation of poly(lactic acid) (PLA)-coated controlled-release fertilizer. A multi-diffusion model that consists of coupled partial differential equations is used to study the diffusion and chemical reaction (autocatalytic degradation) simultaneously. The model is solved using an analytical-numerical method. Firstly, the model equation is transformed using the Laplace transformation as the Laplace transform cannot be inverted analytically. Numerical inversion of the Laplace transform is used by employing the Zakian method. The solution is useful in predicting the nutrient release profiles at various diffusivity, concentration of extraction medium, and reaction rates. It also helps in explaining the transformation of autocatalytic concentration in the coating material for various reaction rates, times of reaction, and reaction-multi diffusion. The solution is also applicable to the other biodegradable polymer-coated controlled-release fertilizers. Full article

(This article belongs to the Special Issue Biodegradable Polymers)

► Show Figures

Graphical abstract

4122 KiB

Open AccessArticle

Influence of Biodegradable Polymer Properties on Antifouling Paints Activity

by Marion Loriot, Isabelle Linossier, Karine Vallée-Réhel and Fabienne Faÿ

Polymers 2017, 9(2), 36; https://doi.org/10.3390/polym9020036 - 25 Jan 2017

Cited by 16 | Viewed by 7267

Abstract

The development of new antifouling paints requires understanding the parameters involved in antifouling activity and to develop new analytical tools for their evaluation. A series of biodegradable poly(ε-caprolactone-co-δ-valerolactone) copolymers varying by molecular weight and composition were synthesized, characterized and formulated as [...] Read more.

The development of new antifouling paints requires understanding the parameters involved in antifouling activity and to develop new analytical tools for their evaluation. A series of biodegradable poly(ε-caprolactone-co-δ-valerolactone) copolymers varying by molecular weight and composition were synthesized, characterized and formulated as antifouling paints. The physico-chemical properties such as hydration, degradation, erosion and lixiviation of paints were studied. Microfouling (bacteria and microalgae) was observed by microscopic observations in a short delay, whereas macrofouling colonization was observed by visual inspection during one year. The antifouling activity of paints was modified by varying the composition and molecular weight of copolymer. The crystallinity appears to play a major role in antifouling activity, however the involvement of other properties such as hydration, degradation or erosion remains difficult to understand. Confocal laser scanning and scanning electron microscopes were used for the evaluation of antifouling paints. Results show that microalgae seem to be a pertinent indicator of antifouling activity. Full article

(This article belongs to the Special Issue Biodegradable Polymers)

► Show Figures

Graphical abstract

20983 KiB

Open AccessArticle

A Highly Hydrophilic and Biodegradable Novel Poly(amide-imide) for Biomedical Applications

by Qiying Zou, Qian Zhou, Langlang Liu and Honglian Dai

Polymers 2016, 8(12), 441; https://doi.org/10.3390/polym8120441 - 19 Dec 2016

Cited by 8 | Viewed by 6918

Abstract

A novel biodegradable poly(amide-imide) (PAI) with good hydrophilicity was synthesized by incorporation of l-glycine into the polymer chain. For comparison purposes, a pure PAI containing no l-glycine was also synthesized with a three-step method. In this study, we evaluated the novel [...] Read more.

A novel biodegradable poly(amide-imide) (PAI) with good hydrophilicity was synthesized by incorporation of l-glycine into the polymer chain. For comparison purposes, a pure PAI containing no l-glycine was also synthesized with a three-step method. In this study, we evaluated the novel PAI’s thermal stability, hydrophilicity, solubility, biodegradability and ability to support bone marrow mesenchymal stem cell (BMSC) adhesion and growth by comparing with the pure PAI. The hydrophilic tests demonstrated that the novel PAI has possible hydrophilicity at a 38° water contact angle on the molecule surface and is about two times more hydrophilic than the pure PAI. Due to an extra unit of l-glycine in the novel PAI, the average degradation rate was about 2.4 times greater than that of the pure PAI. The preliminary biocompatibility studies revealed that all the PAIs are cell compatible, but the pure PAI exhibited much lower cell adhesion than the l-glycine-incorporated novel PAI. The hydrophilic surface of the novel PAI was more suitable for cell adhesion, suggesting that the surface hydrophilicity plays an important role in enhancing cell adhesion and growth. Full article

(This article belongs to the Special Issue Biodegradable Polymers)

► Show Figures

Graphical abstract

5104 KiB

Open AccessArticle

Study of Non-Isothermal Crystallization of Polydioxanone and Analysis of Morphological Changes Occurring during Heating and Cooling Processes

by Yolanda Márquez, Lourdes Franco, Pau Turon, Juan Carlos Martínez and Jordi Puiggalí

Polymers 2016, 8(10), 351; https://doi.org/10.3390/polym8100351 - 28 Sep 2016

Cited by 19 | Viewed by 8017

Abstract

Non-isothermal crystallization kinetics of polydioxanone (PDO), a polymer with well-established applications as bioabsorbable monofilar suture, was investigated by Avrami, Mo, and isoconversional methodologies. Results showed Avrami exponents appearing in a relatively narrow range (i.e., between 3.76 and 2.77), which suggested a three-dimensional spherulitic [...] Read more.

Non-isothermal crystallization kinetics of polydioxanone (PDO), a polymer with well-established applications as bioabsorbable monofilar suture, was investigated by Avrami, Mo, and isoconversional methodologies. Results showed Avrami exponents appearing in a relatively narrow range (i.e., between 3.76 and 2.77), which suggested a three-dimensional spherulitic growth and instantaneous nucleation at high cooling rates. The nucleation mechanism changed to sporadic at low rates, with both crystallization processes being detected in the differential scanning calorimetry (DSC) cooling traces. Formation of crystals was hindered as the material crystallized because of a decrease in the motion of molecular chains. Two secondary nucleation constants were derived from calorimetric data by applying the methodology proposed by Vyazovkin and Sbirrazzuoli through the estimation of effective activation energies. In fact, typical non-isothermal crystallization analysis based on the determination of crystal growth by optical microscopy allowed secondary nucleation constants of 3.07 × 10⁵ K² and 1.42 × 10⁵ K² to be estimated. Microstructure of sutures was characterized by a stacking of lamellae perpendicularly oriented to the fiber axis and the presence of interlamellar and interfibrillar amorphous regions. The latter became enhanced during heating treatments due to loss of partial chain orientation and decrease of electronic density. Degradation under various pH media revealed different macroscopic morphologies and even a distinct evolution of lamellar microstructure during subsequent heating treatments. Full article

(This article belongs to the Special Issue Biodegradable Polymers)

► Show Figures

Graphical abstract

8310 KiB

Open AccessArticle

Novel Electrospun Polylactic Acid Nanocomposite Fiber Mats with Hybrid Graphene Oxide and Nanohydroxyapatite Reinforcements Having Enhanced Biocompatibility

by Chen Liu, Hoi Man Wong, Kelvin Wai Kwok Yeung and Sie Chin Tjong

Polymers 2016, 8(8), 287; https://doi.org/10.3390/polym8080287 - 8 Aug 2016

Cited by 98 | Viewed by 9500

Abstract

Graphene oxide (GO) and a nanohydroxyapatite rod (nHA) of good biocompatibility were incorporated into polylactic acid (PLA) through electrospinning to form nanocomposite fiber scaffolds for bone tissue engineering applications. The preparation, morphological, mechanical and thermal properties, as well as biocompatibility of electrospun PLA [...] Read more.

Graphene oxide (GO) and a nanohydroxyapatite rod (nHA) of good biocompatibility were incorporated into polylactic acid (PLA) through electrospinning to form nanocomposite fiber scaffolds for bone tissue engineering applications. The preparation, morphological, mechanical and thermal properties, as well as biocompatibility of electrospun PLA scaffolds reinforced with GO and/or nHA were investigated. Electron microscopic examination and image analysis showed that GO and nHA nanofillers refine the diameter of electrospun PLA fibers. Differential scanning calorimetric tests showed that nHA facilitates the crystallization process of PLA, thereby acting as a nucleating site for the PLA molecules. Tensile test results indicated that the tensile strength and elastic modulus of the electrospun PLA mat can be increased by adding 15 wt % nHA. The hybrid nanocomposite scaffold with 15 wt % nHA and 1 wt % GO fillers exhibited higher tensile strength amongst the specimens investigated. Furthermore, nHA and GO nanofillers enhanced the water uptake of PLA. Cell cultivation, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and alkaline phosphatase tests demonstrated that all of the nanocomposite scaffolds exhibit higher biocompatibility than the pure PLA mat, particularly for the scaffold with 15 wt % nHA and 1 wt % GO. Therefore, the novel electrospun PLA nanocomposite scaffold with 15 wt % nHA and 1 wt % GO possessing a high tensile strength and modulus, as well as excellent cell proliferation is a potential biomaterial for bone tissue engineering applications. Full article

(This article belongs to the Special Issue Biodegradable Polymers)

► Show Figures

Graphical abstract

6909 KiB

Open AccessFeature PaperArticle

3D Culture of Chondrocytes in Gelatin Hydrogels with Different Stiffness

by Xiaomeng Li, Shangwu Chen, Jingchao Li, Xinlong Wang, Jing Zhang, Naoki Kawazoe and Guoping Chen

Polymers 2016, 8(8), 269; https://doi.org/10.3390/polym8080269 - 26 Jul 2016

Cited by 174 | Viewed by 15737

Abstract

Gelatin hydrogels can mimic the microenvironments of natural tissues and encapsulate cells homogeneously, which makes them attractive for cartilage tissue engineering. Both the mechanical and biochemical properties of hydrogels can affect the phenotype of chondrocytes. However, the influence of each property on chondrocyte [...] Read more.

Gelatin hydrogels can mimic the microenvironments of natural tissues and encapsulate cells homogeneously, which makes them attractive for cartilage tissue engineering. Both the mechanical and biochemical properties of hydrogels can affect the phenotype of chondrocytes. However, the influence of each property on chondrocyte phenotype is unclear due to the difficulty in separating the roles of these properties. In this study, we aimed to study the influence of hydrogel stiffness on chondrocyte phenotype while excluding the role of biochemical factors, such as adhesion site density in the hydrogels. By altering the degree of methacryloyl functionalization, gelatin hydrogels with different stiffnesses of 3.8, 17.1, and 29.9 kPa Young’s modulus were prepared from the same concentration of gelatin methacryloyl (GelMA) macromers. Bovine articular chondrocytes were encapsulated in the hydrogels and cultured for 14 days. The influence of hydrogel stiffness on the cell behaviors including cell viability, cell morphology, and maintenance of chondrogenic phenotype was evaluated. GelMA hydrogels with high stiffness (29.9 kPa) showed the best results on maintaining chondrogenic phenotype. These results will be useful for the design and preparation of scaffolds for cartilage tissue engineering. Full article

(This article belongs to the Special Issue Biodegradable Polymers)

► Show Figures

Graphical abstract

4051 KiB

Open AccessFeature PaperArticle

Thermo-Responsive Polyurethane Hydrogels Based on Poly(ε-caprolactone) Diol and Amphiphilic Polylactide-Poly(Ethylene Glycol) Block Copolymers

by Shan-hui Hsu, Cheng-Wei Chen, Kun-Che Hung, Yi-Chun Tsai and Suming Li

Polymers 2016, 8(7), 252; https://doi.org/10.3390/polym8070252 - 5 Jul 2016

Cited by 24 | Viewed by 8631

Abstract

Waterborne polyurethane (PU) based on poly(ε-caprolactone) (PCL) diol and an amphiphilic polylactide-poly(ethylene glycol) (PLA-PEG) diblock copolymer was synthesized. The molar ratio of PCL/PLA-PEG was 9:1 with different PLA chain lengths. The PU nanoparticles were characterized by dynamic light scattering (DLS), small angle X-ray [...] Read more.

Waterborne polyurethane (PU) based on poly(ε-caprolactone) (PCL) diol and an amphiphilic polylactide-poly(ethylene glycol) (PLA-PEG) diblock copolymer was synthesized. The molar ratio of PCL/PLA-PEG was 9:1 with different PLA chain lengths. The PU nanoparticles were characterized by dynamic light scattering (DLS), small angle X-ray scattering (SAXS) and rheological analysis. The water contact angle measurement, infrared spectroscopy, wide angle X-ray scattering (WAXS), thermal and mechanical analyses were conducted on PU films. Significant changes in physio-chemical properties were observed for PUs containing 10 mol % of amphiphilic blocks. The water contact angle was reduced to 12°–13°, and the degree of crystallinity was 5%–10%. The PU dispersions underwent sol-gel transition upon the temperature rise to 37 °C. The gelation time increased as the PLA chain length increased. In addition, the fractal dimension of each gel was close to that of a percolation cluster. Moreover, PU4 with a solid content of 26% could support the proliferation of human mesenchymal stem cells (hMSCs). Therefore, thermo-responsive hydrogels with tunable properties are promising injectable materials for cell or drug delivery. Full article

(This article belongs to the Special Issue Biodegradable Polymers)

► Show Figures

Graphical abstract

3377 KiB

Open AccessArticle

The Influence of Lyophilized EmuGel Silica Microspheres on the Physicomechanical Properties, In Vitro Bioactivity and Biodegradation of a Novel Ciprofloxacin-Loaded PCL/PAA Scaffold

by Mostafa Mabrouk, Yahya Essop Choonara, Pradeep Kumar, Lisa Claire Du Toit and Viness Pillay

Polymers 2016, 8(6), 232; https://doi.org/10.3390/polym8060232 - 15 Jun 2016

Cited by 10 | Viewed by 7102

Abstract

A new composite poly(caprolactone) (PCL) and poly(acrylic acid) (PAA) (PCL:PAA 1:5) scaffold was synthesized via dispersion of PCL particles into a PAA network. Silica microspheres (Si) (2–12 μm) were then prepared by a lyophilized micro-emulsion/sol-gel (Emugel) system using varying weight ratios. The model [...] Read more.

A new composite poly(caprolactone) (PCL) and poly(acrylic acid) (PAA) (PCL:PAA 1:5) scaffold was synthesized via dispersion of PCL particles into a PAA network. Silica microspheres (Si) (2–12 μm) were then prepared by a lyophilized micro-emulsion/sol-gel (Emugel) system using varying weight ratios. The model drug ciprofloxacin (CFX) was used for in situ incorporation into the scaffold. The physicochemical and thermal integrity, morphology and porosity of the system was analyzed by X-Ray Diffraction (XRD), Attenuated Total Refelctance Fourier Transform Infrared (ATR-FTIR), Differential Scanning Calorimetry (DSC), SEM, surface area analysis and liquid displacement, respectively. The mechanical properties of the scaffold were measured by textural analysis and in vitro bioactivity, biodegradation and pH variations were evaluated by XRD, FTIR and SEM after immersion in Simulated Body Fluid (SBF). The in vitro and in vivo studies of the prepared scaffold were considered as future aspects for this study. CFX release was determined in phosphate buffer saline (PBS) (pH 7.4; 37 °C). The incorporation of the Si microspheres and CFX into the scaffold was confirmed by XRD, FTIR, DSC and SEM, and the scaffold microstructure was dependent on the concentration of Si microspheres and the presence of CFX. The system displayed enhanced mechanical properties (4.5–14.73 MPa), in vitro bioactivity, biodegradation and controlled CFX release. Therefore, the PCL/PAA scaffolds loaded with Si microspheres and CFX with a porosity of up to 87% may be promising for bone tissue engineering. Full article

(This article belongs to the Special Issue Biodegradable Polymers)

► Show Figures

Graphical abstract

2588 KiB

Open AccessArticle

Biodegradable Polyphosphazene Based Peptide-Polymer Hybrids

by Anne Linhardt, Michael König, Wolfgang Schöfberger, Oliver Brüggemann, Alexander K. Andrianov and Ian Teasdale

Polymers 2016, 8(4), 161; https://doi.org/10.3390/polym8040161 - 22 Apr 2016

Cited by 30 | Viewed by 10286

Abstract

A novel series of peptide based hybrid polymers designed to undergo enzymatic degradation is presented, via macrosubstitution of a polyphosphazene backbone with the tetrapeptide Gly-Phe-Leu-Gly. Further co-substitution of the hybrid polymers with hydrophilic polyalkylene oxide Jeffamine M-1000 leads to water soluble and biodegradable [...] Read more.

A novel series of peptide based hybrid polymers designed to undergo enzymatic degradation is presented, via macrosubstitution of a polyphosphazene backbone with the tetrapeptide Gly-Phe-Leu-Gly. Further co-substitution of the hybrid polymers with hydrophilic polyalkylene oxide Jeffamine M-1000 leads to water soluble and biodegradable hybrid polymers. Detailed degradation studies, via ³¹P NMR spectroscopy, dynamic light scattering and field flow fractionation show the polymers degrade via a combination of enzymatic, as well as hydrolytic pathways. The peptide sequence was chosen due to its known property to undergo lysosomal degradation; hence, these degradable, water soluble polymers could be of significant interest for the use as polymer therapeutics. In this context, we investigated conjugation of the immune response modifier imiquimod to the polymers via the tetrapeptide and report the self-assembly behavior of the conjugate, as well as its enzymatically triggered drug release behavior. Full article

(This article belongs to the Special Issue Biodegradable Polymers)

► Show Figures

Graphical abstract

3008 KiB

Open AccessArticle

Poly-Lactide/Exfoliated C30B Interactions and Influence on Thermo-Mechanical Properties Due to Artificial Weathering

by Wendy Margarita Chávez-Montes, Guillermo González-Sánchez and Sergio Gabriel Flores-Gallardo

Polymers 2016, 8(4), 154; https://doi.org/10.3390/polym8040154 - 20 Apr 2016

Cited by 6 | Viewed by 7250

Abstract

Thermal stability as well as enhanced mechanical properties of poly-lactide (PLA) can increase PLA applications for short-use products. The conjunction of adequate molecular weight (M_W) as well as satisfactory thermo-mechanical properties, together, can lead to the achievement of suitable properties. [...] Read more.

Thermal stability as well as enhanced mechanical properties of poly-lactide (PLA) can increase PLA applications for short-use products. The conjunction of adequate molecular weight (M_W) as well as satisfactory thermo-mechanical properties, together, can lead to the achievement of suitable properties. However, PLA is susceptible to thermal degradation and thus an undesired decay of M_W and a decrease of its mechanical properties during processing. To avoid this PLA degradation, nanofiller is incorporated as reinforcement to increase its thermo-mechanical properties. There are many papers focusing on filler effects on the thermal stability and mechanical properties of PLA/nanocomposites; however, these investigations lack an explanation of polymer/filler interactions. We propose interactions between PLA and Cloisite30B (C30B) as nanofiller. We also study the effects on the thermal and mechanical properties due to molecular weight decay after exposure to artificial weathering. PLA blank and nanocomposites were subjected to three time treatments (0, 176, and 360 h) of exposure to artificial weathering in order to achieve comparable materials with different M_W. M_W was acquired by means of Gel Permeation Chromatography (GPC). Thermo-mechanical properties were investigated through Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), X-ray Diffraction (XRD), Dynamic Mechanical Thermal Analysis (DMTA) and Fourier Transform Infrared Spectroscopy (FTIR). Full article

(This article belongs to the Special Issue Biodegradable Polymers)

► Show Figures

Graphical abstract

1882 KiB

Open AccessArticle

Physical and Mechanical Evaluation of Five Suture Materials on Three Knot Configurations: An in Vitro Study

by Desire Abellán, José Nart, Andrés Pascual, Robert E. Cohen and Javier D. Sanz-Moliner

Polymers 2016, 8(4), 147; https://doi.org/10.3390/polym8040147 - 20 Apr 2016

Cited by 36 | Viewed by 9704

Abstract

The aim of this study was to evaluate and compare the mechanical properties of five suture materials on three knot configurations when subjected to different physical conditions. Five 5-0 (silk, polyamide 6/66, polyglycolic acid, glycolide-e-caprolactone copolymer, polytetrafluoroethylene) suture materials were used. Ten samples [...] Read more.

The aim of this study was to evaluate and compare the mechanical properties of five suture materials on three knot configurations when subjected to different physical conditions. Five 5-0 (silk, polyamide 6/66, polyglycolic acid, glycolide-e-caprolactone copolymer, polytetrafluoroethylene) suture materials were used. Ten samples per group of each material were used. Three knot configurations were compared A.2=1=1 (forward–forward–reverse), B.2=1=1 (forward–reverse–forward), C.1=2=1 (forward–forward–reverse). Mechanical properties (failure load, elongation, knot slippage/breakage) were measured using a universal testing machine. Samples were immersed in three different pH concentrations (4,7,9) at room temperature for 7 and 14 days. For the thermal cycle process, sutures were immersed in two water tanks at different temperatures (5 and 55 °C). Elongation and failure load were directly dependent on the suture material. Polyglycolic acid followed by glycolide-e-caprolactone copolymer showed the most knot failure load, while polytetrafluoroethylene showed the lowest (P < 0.001). Physical conditions had no effect on knot failure load (P = 0.494). Statistically significant differences were observed between knot configurations (P = 0.008). Additionally, individual assessment of suture material showed statistically significant results for combinations of particular knot configurations. Physical conditions, such as pH concentration and thermal cycle process, have no influence on suture mechanical properties. However, knot failure load depends on the suture material and knot configuration used. Consequently, specific suturing protocols might be recommended to obtain higher results of knot security. Full article

(This article belongs to the Special Issue Biodegradable Polymers)

► Show Figures

Graphical abstract

1775 KiB

Open AccessArticle

Application of Chitinous Materials in Production and Purification of a Poly(l-lactic acid) Depolymerase from Pseudomonas tamsuii TKU015

by Tzu-Wen Liang, Shan-Ni Jen, Anh Dzung Nguyen and San-Lang Wang

Polymers 2016, 8(3), 98; https://doi.org/10.3390/polym8030098 - 22 Mar 2016

Cited by 26 | Viewed by 6335

Abstract

The management of fishery residues and plastics is considered to be a vital strategy for conserving resources and maintaining the quality of the environment. Poly(l-lactic acid) (PLA) is a commercially promising, renewable, and biodegradable plastic. In this study, a PLA depolymerase [...] Read more.

The management of fishery residues and plastics is considered to be a vital strategy for conserving resources and maintaining the quality of the environment. Poly(l-lactic acid) (PLA) is a commercially promising, renewable, and biodegradable plastic. In this study, a PLA depolymerase was produced in a squid pen powder (SPP) and recycled plastic waste (PLA powder)-containing medium by Pseudomonas tamsuii TKU015, a bacterial strain isolated from Taiwanese soil. This PLA depolymerase had a molecular weight of 58 kDa and was purified to homogeneity from the supernatant of a TKU015 culture. The optimum pH of TKU015 PLA depolymerase is 10, and the optimal temperature of the enzyme is 60 °C. In addition to PLA, TKU015 PLA depolymerase degraded fibrinogen and tributyrin, but did not hydrolyze casein, triolein, and poly(β-hydroxybutyrate). Taken together, these data demonstrate that P. tamsuii TKU015 produces a PLA depolymerase to utilize SPP and polylactide as carbon/nitrogen sources. Full article

(This article belongs to the Special Issue Biodegradable Polymers)

► Show Figures

Graphical abstract

5235 KiB

Open AccessArticle

Influence of Electrospinning Parameters on Fiber Diameter and Mechanical Properties of Poly(3-Hydroxybutyrate) (PHB) and Polyanilines (PANI) Blends

by Ahmed M. El-hadi and Fatma Y. Al-Jabri

Polymers 2016, 8(3), 97; https://doi.org/10.3390/polym8030097 - 22 Mar 2016

Cited by 41 | Viewed by 7796

Abstract

Random and oriented fibers of poly (3-hydroxybutyrate) (PHB) and their blends were manufactured using electrospinning using a co-solvent. The kind and the concentration of the co-solvent affected the diameter of electrospun fibers. The morphology, thermal analysis, and crystalline structure of electrospun fibers was [...] Read more.

Random and oriented fibers of poly (3-hydroxybutyrate) (PHB) and their blends were manufactured using electrospinning using a co-solvent. The kind and the concentration of the co-solvent affected the diameter of electrospun fibers. The morphology, thermal analysis, and crystalline structure of electrospun fibers was studied using polarized optical microscop (POM), Differential scanning colametry (DSC), Scanning Electron Microscopy (SEM), Wide angle X-ray diffraction (WAXD), and FT-IR analysis. The diameter of the electrospun fibers decreases with increasing collector speed for the blends compared to pure PHB, which are about 6 µm in diameter. The fibers obtained from blends reduce to 2 µm. The aligned electrospun fiber mats obtained from pure PHB showed no signs of necking at different take-up speeds, but the blends show multiple necking. It was found by FT-IR that the peak intensity at 1379 cm⁻¹ was lower by take up speed than in casting films; this peak is sensitive to crystallinity of PHB. The addition of polyanilines (PANIs) to (PHB) with a plasticizer decreases the diameter of the electrospun fiber. Full article

(This article belongs to the Special Issue Biodegradable Polymers)

► Show Figures

Graphical abstract

1536 KiB

Open AccessCommunication

Polylactide/Montmorillonite Hybrid Latex as a Barrier Coating for Paper Applications

by Davide Bandera, Veronika R. Meyer, David Prevost, Tanja Zimmermann and Luciano F. Boesel

Polymers 2016, 8(3), 75; https://doi.org/10.3390/polym8030075 - 4 Mar 2016

Cited by 19 | Viewed by 7181

Abstract

We developed a paper coating for the potential application in food packaging based on polylactide and montmorillonite. It is applied to the paper in the form of a stable, water-based latex with a solid content of 25–28 wt %. The latex is prepared [...] Read more.

We developed a paper coating for the potential application in food packaging based on polylactide and montmorillonite. It is applied to the paper in the form of a stable, water-based latex with a solid content of 25–28 wt %. The latex is prepared from a commercially available polylactide, surfactants, montmorillonite, a plasticizer, chloroform (to be removed later) and water by an emulsion/solvent evaporation procedure. This coating formulation is applied to the paper substrate by bar-coating, followed by hot-pressing at 150 °C. The coated papers achieved up to an 85% improvement in water vapor transmission rates when compared to the pristine papers. The coating latex is prepared from inexpensive materials and can be used for a solvent-free coating process. In addition, the ingredients of the latex are non-toxic; thus, the coated papers can be safely used for food packaging. Full article

(This article belongs to the Special Issue Biodegradable Polymers)

► Show Figures

Graphical abstract

1527 KiB

Open AccessFeature PaperArticle

Fabrication of Porous Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) Monoliths via Thermally Induced Phase Separation

by Takashi Tsujimoto, Nao Hosoda and Hiroshi Uyama

Polymers 2016, 8(3), 66; https://doi.org/10.3390/polym8030066 - 29 Feb 2016

Cited by 18 | Viewed by 8813

Abstract

This study deals with the fabrication of biodegradable porous materials from bacterial polyester, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P3HB3HH_x), via thermally induced phase separation. P3HB3HH_x monoliths with topological porous structure were prepared by dissolution of P3HB3HH_x in dimethyl sulfoxide (DMSO) at [...] Read more.

This study deals with the fabrication of biodegradable porous materials from bacterial polyester, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P3HB3HH_x), via thermally induced phase separation. P3HB3HH_x monoliths with topological porous structure were prepared by dissolution of P3HB3HH_x in dimethyl sulfoxide (DMSO) at 85 °C and subsequent quenching. The microstructure of the resulting P3HB3HH_x monoliths was changed by the P3HB3HH_x concentration of the polymer solution. Differential scanning calorimetry and polarized optical microscope analysis revealed that the P3HB3HH_x monoliths crystallized during phase separation and the subsequent aging. The mechanical properties, such as compression modulus and stress, of the monoliths depended on the 3-hydroxyhexanoate content of P3HB3HH_x. Furthermore, the P3HB3HH_x monolith absorbed linseed oil in preference to water in a plant oil–water mixture. In combination with the biodegradable character of P3HB3HH_x, the present study is expected to contribute to the development of bio-based materials. Full article

(This article belongs to the Special Issue Biodegradable Polymers)

► Show Figures

Graphical abstract

Review

Jump to: Research

4819 KiB

Open AccessReview

Modification and Potential Application of Short-Chain-Length Polyhydroxyalkanoate (SCL-PHA)

by Shichao Wang, Wei Chen, Hengxue Xiang, Junjie Yang, Zhe Zhou and Meifang Zhu

Polymers 2016, 8(8), 273; https://doi.org/10.3390/polym8080273 - 28 Jul 2016

Cited by 92 | Viewed by 13489

Abstract

As the only kind of naturally-occurring biopolyester synthesized by various microorganisms, polyhydroxyalkanoate (PHA) shows a great market potential in packaging, fiber, biomedical, and other fields due to its biodegradablity, biocompatibility, and renewability. However, the inherent defects of scl-PHA with low 3HV or 4HB [...] Read more.

As the only kind of naturally-occurring biopolyester synthesized by various microorganisms, polyhydroxyalkanoate (PHA) shows a great market potential in packaging, fiber, biomedical, and other fields due to its biodegradablity, biocompatibility, and renewability. However, the inherent defects of scl-PHA with low 3HV or 4HB content, such as high stereoregularity, slow crystallization rate, and particularly the phenomena of formation of large-size spherulites and secondary crystallization, restrict the processing and stability of scl-PHA, as well as the application of its products. Many efforts have focused on the modification of scl-PHA to improve the mechanical properties and the applicability of obtained scl-PHA products. The modification of structure and property together with the potential applications of scl-PHA are covered in this review to give a comprehensive knowledge on the modification and processing of scl-PHA, including the effects of physical blending, chemical structure design, and processing conditions on the crystallization behaviors, thermal stability, and mechanical properties of scl-PHA. Full article

(This article belongs to the Special Issue Biodegradable Polymers)

► Show Figures

Figure 1

1067 KiB

Open AccessFeature PaperReview

Bio-Based Polymers with Potential for Biodegradability

by Thomas F. Garrison, Amanda Murawski and Rafael L. Quirino

Polymers 2016, 8(7), 262; https://doi.org/10.3390/polym8070262 - 14 Jul 2016

Cited by 213 | Viewed by 23990

Abstract

A variety of renewable starting materials, such as sugars and polysaccharides, vegetable oils, lignin, pine resin derivatives, and proteins, have so far been investigated for the preparation of bio-based polymers. Among the various sources of bio-based feedstock, vegetable oils are one of the [...] Read more.

A variety of renewable starting materials, such as sugars and polysaccharides, vegetable oils, lignin, pine resin derivatives, and proteins, have so far been investigated for the preparation of bio-based polymers. Among the various sources of bio-based feedstock, vegetable oils are one of the most widely used starting materials in the polymer industry due to their easy availability, low toxicity, and relative low cost. Another bio-based plastic of great interest is poly(lactic acid) (PLA), widely used in multiple commercial applications nowadays. There is an intrinsic expectation that bio-based polymers are also biodegradable, but in reality there is no guarantee that polymers prepared from biorenewable feedstock exhibit significant or relevant biodegradability. Biodegradability studies are therefore crucial in order to assess the long-term environmental impact of such materials. This review presents a brief overview of the different classes of bio-based polymers, with a strong focus on vegetable oil-derived resins and PLA. An entire section is dedicated to a discussion of the literature addressing the biodegradability of bio-based polymers. Full article

(This article belongs to the Special Issue Biodegradable Polymers)

► Show Figures

Graphical abstract

Journal Menu

Journal Browser

Biodegradable Polymers

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Benefits of Publishing in a Special Issue

Related Special Issue

Published Papers (19 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI