Types Of Biodegradable Materials Research Articles

Lignin‐based nitrogen and phosphorus‐containing polylactic acid with flame‐retardant performances

AbstractPolylactic acid (PLA) is a new type of biodegradable material that has been applied in many fields such as extrusion, injection molding, film drawing, and spinning. In contrary, it does not have flame retardancy. In this paper, N‐PCDL was synthesized by amidation reaction between COOH of PCDL and NH2 of tetraethylenepentamine (TEPA), followed by an Atherton‐Todd reaction of unreacted NH2 at the other end of TEPA with PH of DOPO to prepare a novel lignin‐based flame retardant containing nitrogen and phosphorus (NP‐PCDL). The Fourier transform infrared spectroscopy (FT‐IR) and nuclear magnetic hydrogen spectroscopy (1H NMR) analysis results showed that proton peaks of CONH, PN, and NH appeared in the NP‐PCDL spectrum, while the characteristic absorption peak of PH bond disappeared in DOPO, the X‐ray photoelectron spectroscopy (XPS) results showed that the degraded lignin consisted of elements C and O, while NP‐PCDL consisted of elements C, O, N and P. The above results indicated that NP‐PCDL was successfully prepared. NP‐PCDL accounted for 3% (mass percentage, the same below), 5% and 10% of PLA, then lignin based flame‐retardant PLA composites were prepared by internal mixing and injection molding. Thermogravimetric analysis (TGA) showed that the residual carbon of PLA/3% NP‐PCDL, PLA/5% NP‐PCDL and PLA/10% NP‐PCDL at 800°C were higher than that of pure PLA, with the increase of 56.56%, 97.54%, and 301.64%, respectively; The analysis of SEM, XPS, and Raman showed that PLA/NP‐PCDL formed dense, regular and highly graphitized residual carbon with phosphorus nitrogen structure during the combustion process. At the same time, NH3, H2O and PO˙ free radicals were released, which could dilute combustible gases, destroy free radical chain reaction, isolate combustible gases and heat, so as to play a flame‐retardant role.

Application and Perspectives: Magnesium Materials in Bone Regeneration.

The field of bone regeneration has always been a hot and difficult research area, and there is no perfect strategy at present. As a new type of biodegradable material, magnesium alloys have excellent mechanical properties and bone promoting ability. Compared with other inert metals, magnesium alloys have significant advantages and broad application prospects in the field of bone regeneration. By searching the official Web sites and databases of various funds, this paper summarizes the research status of magnesium composites in the field of bone regeneration and introduces the latest scientific research achievements and clinical transformations of scholars in various countries and regions, such as improving the corrosion resistance of magnesium alloys by adding coatings. Finally, this paper points out the current problems and challenges, aiming to provide ideas and help for the development of new strategies for the treatment of bone defects and fractures.

Exploring the use of Biodegradable Polymer Materials in Sustainable 3D Printing

The use of biodegradable materials in 3D printing has gained attention due to its potential in addressing environmental concerns in the manufacturing industry. This paper aims to explore the current state of research and development in sustainable 3D printing using biodegradable materials. The research found that biodegradable materials, such as bioplastics, are being increasingly used in 3D printing as an eco-friendly alternative to traditional materials. Various types of biodegradable materials have been tested, including Polylactic Acid (PLA), cellulose-based materials, and starch-based materials. One of the main advantages of using biodegradable materials in 3D printing is its potential to reduce the carbon footprint of the production process. These materials are derived from renewable resources and have a lower environmental impact compared to non-biodegradable materials, such as petroleum-based plastics. However, the use of biodegradable materials in 3D printing also presents challenges, including limited availability and higher production costs, as well as the need for specific print settings and post-processing methods. Further research is needed to optimize the use of biodegradable materials in 3D printing and to develop new materials with improved properties. Collaboration between material scientists and 3D printing manufacturers is crucial to advancing sustainable 3D printing using biodegradable materials.

The influence of polylactide/hydroxyapatite composite material crystallinity on the polymer structure degradation rate

Introduction Assessment of biological characteristics of polylactide/hydroxyapatite (PLLA/HA) biodegradable materials is requiered to specify indications for the use of PLLA/HA composite implants in clinical practice.The present study was aimed to measure the kinetics of calcium and phosphate release from PLLA and its dependence on polymer structure crystallinity. Material and methods Four types of biodegradable materials were studied in vitro. Samples of type 1 and type 3 made of crystalline PLLA after annealing contained 25 % and 50 % of HA mass fraction, respectively. Samples of type 2 and type 4 made of amorphous PLLA (without annealing) contained 25 % and 50 % of HA mass fraction, respectively. In every group, 6 samples were tested. The samples were incubated in an aqueous medium at 37 °C for 52 weeks. The rate of PLLA degradation was assessed by the accumulation of lactate monomer in the hydrolysate. The concentrations of calcium ions and phosphate ions were determined for assessment the HA hydrolysis rate. The degree of crystallinity of the polymer matrix was evaluated by scanning calorimetry.Results The hydrolysis of PLLA and HA in the samples was not simultaneous. The PLLA was hydrolyzed first followed by HA hydrolysis. By the moment of complete hydrolysis of PLLA, there was only 15 % of hydrolyzed HA. The release of calcium ions occurred from the sixth week of incubation for all tested samples, that of phosphate ions from the third week. The total amount of the released calcium ions and phosphate ions decreased in the line: material 3 > material 4 > material 1 > material 2. Calcium ions in the hydrolysates were detected up to 42 weeks of incubation, phosphate ions up to the 52nd week.Conclusion Higher crystallinity of PLLA achieved by annealing results in increased rate of hydrolysis of HA from PLLA matrix. Biological activity of PLLA/HA implants can be determined by degree of polymer crystallinity and saturation with HA.

Polylactic acid flame‐retardant composite preparation and investigation of flame‐retardant characteristics

AbstractPolylactic acid (PLA) is a new type of biodegradable material with good mechanical properties, and is widely used in many fields. However, as PLA is highly flammable, it is necessary to conduct flame‐retardant modification research on PLA. Phosphorus heterophilic flame retardants are low smoke, non‐toxic and have high flame‐retardant efficiency, and also have broad application prospects. In this study, a phosphazene flame retardant, 9,10‐dihydro‐9‐oxa‐10‐phosphazene‐10‐yl‐hydroxy‐phenol (abbreviated as DOPO‐PHBA), was synthesized. The PLA/ECE/DOPO‐PHBA flame‐retardant composites were prepared by adding DOPO‐PHBA and epoxy chain extender (ECE) into PLA. Thermal, mechanical, and flame‐retardant properties, as well as microscopic morphology of the PLA flame‐retardant composites were characterized and analyzed, and the flame‐retardant mechanism was discussed. Results show that when the flame‐retardant DOPO‐PHBA is added at 5 wt%, the PLA composites can reach the V‐0 level of combustion, and the corresponding LOI value is 30.0% at this time, and the LOI value increases from 22.5% to 33.6% with the increase of the flame‐retardant content. In addition, PLA composites still have good mechanical properties, and the cone heat, carbon residue and the thermal decomposition process shows that the flame‐retardant causes a two‐phase flame‐retardant mechanism on PLA with the gas and condensed phases acting in synergy. High flame retardancy is mainly attributed to free radical quenching, gas dilution, and the thermal barrier caused by the carbon layer. This work provides a simple and scalable method for the preparation of high‐performance flame‐retardant PLA materials.

Ultrafine- and uniform-grained biodegradable Zn-0.5Mn alloy: Grain refinement mechanism, corrosion behavior, and biocompatibility in vivo.

An ultrafine- and uniform-grained Zn-0.5Mn alloy (D3 alloy, stands for deformation rate of 99.5%) is fabricated via multi-pass drawing. The alloy features excellent ductility and elongation properties (up to 245.0%±9.0% at room temperature). Zn-0.5Mn alloys are composed of two phases, namely, Zn and MnZn13. The MnZn13 phase confers multiple effects during refinement by inducing and pinning low-angle boundaries within grains. Meanwhile, the presence of these phases along grain boundaries prevents the growth of new refined grains. D3 shows uniform corrosion behaviors in c-SBF solution on account of the even distribution of the MnZn13 phase in its microstructure. Animal implantation experiments indicate that D3 has good biocompatibility; it does not cause damage to bone tissue or other organs. Taking the results together, D3 may be developed into a new type of biodegradable material with remarkable elongation and corrosion properties and satisfactory biocompatibility for medical applications.

Bone - Graft Delivery Systems of Type PLGA- gentamicin and Collagen - hydroxyapatite - gentamicine

The purpose of this study was the synthesis of two types of biodegradable materials with synthetic polymers (PLGA) or natural polymers (collagen) and hydroxyapatite, followed by determination of the encapsulation percentage of the drug in the polymer. Regardless of the chosen method, the percentage of the encapsulated drug was found to be quite high: 15.92% in the Coll-HA-Genta material and 19.59% respectively in the PLGA-Genta biocomposite. The therapeutic value of gentamicin was improved by encapsulating it in delivery systems, contributing to sustained release for a long time (about 30 days).

Recent Advance in Polymer Based Microspheric Systems for Controlled Protein and Peptide Delivery.

Sustained-release systems made by biodegradable polymers for protein and peptide drug delivery have received considerable attention by academic researchers and major pharmaceutical companies around the world. Various types of biodegradable materials, including natural and synthetic polymers, have been applied to form protein and peptide drug carriers. Among these material candidates, poly lactic acid (PLA) and poly lactic-co-glycolic acid (PLGA) are the most commonly used biodegradable materials in the development of protein and peptide microspheres. In addition, many microsphere preparation technologies, including spray drying, coacervation, multiple emulsion solvent evaporation method and microporous membrane emulsification have been developed for microspheres preparation. In this review, we particularly summarize and briefly introduce the materials and methods that are used to fabricate microspheres as protein delivery systems. The existing opportunities and challenges for successful protein delivery are also discussed.

Preparation and Characterization of Poly(butylene succinate)/Polylactide Blends for Fused Deposition Modeling 3D Printing.

To obtain a new type of biodegradable material with high toughness and strength used for fused deposition modeling (FDM) printing, a series of poly(butylene succinate) (PBS)-based polymer materials was prepared via blending with polylactide (PLA). The rheological, thermal, and mechanical properties as well as FDM printing performances of the blends, such as distortion, cross section, and the interlayer bond strength, were characterized. The results show that with increasing PLA content, the blends possess higher melt viscosity, larger tensile strength, and modulus, which are more suitable for FDM printing. Especially, when the content of PLA is more than 40%, distortion due to residual stress caused by volume shrinkage disappears during the printing process and thus products with good dimensional accuracy and pearl-like gloss are obtained. The results demonstrate that the blend compositions with moderate viscosity, low degree of crystallinity, and high modulus are more suitable for FDM printing. Compared with the low elongation upon breaking of commercially FDM-printed material, the PBS/PLA blend materials exhibit a typical ductile behavior with elongation of 90–300%. Therefore, besides biodegradability, the PBS/PLA blends present excellent mechanical properties and suitability as materials for FDM printing. In addition, our study is expected to provide methods for valuating the suitability of whether a thermoplastic polymer material is suitable for FDM printing or not.

Synthesizing and Characterizing of Gelatin-Chitosan-Bioactive Glass (58s) Scaffolds for Bone Tissue Engineering

Nowadays repairing and regenerating of lost or damaged tissue still remain an important challenge in clinical techniques. Due to the variety of available bone grafts, different types of biodegradable materials are being utilized as a scaffold implant. The basic structure of the bone is an excellent natural composite which contains varieties of polymers and ceramics; therefore, it is important to manufacture a bone scaffold featuring sufficient mechanical strength, a good degree of biocompatibility, biodegradation and an increased rate of formation of new tissue. Bioactive glass has an appealing characteristic which can be utilized for repairing purposes as well as to cause a rapid response from the bone graft. In this study, a composite scaffold based on polymer matrix (gelatin-chitosan) and bioactive glass 58s was synthesized in the laboratory. Five samples of polymer scaffold with different proportions of bioactive glass were designed and investigated. The scaffolds were dried with freeze dryer, and a spongy structure was generated. The composite survey was carried out through FTIR technique to examine the crystallization of the structure, XRD to examine the morphology of the porosities, and SEM to examine the size of porosities and formation of apatite. This study reveals that the size of porosities is about 170–320 μm, which is suitable for angiogenesis and cell growth in the bone. The combination of enhanced properties and the formation of apatite on the surface of the scaffolds make them an ideal option as a bone substitute.

Insights on the properties of levofloxacin-adsorbed Sr- and Mg-doped calcium phosphate powders.

Several types of biodegradable materials have been investigated for the treatment of osteomyelitis. Calcium phosphate (CaP) ceramics are among the most performing materials due to their resemblance to human hard tissues in terms of mineralogical composition, and proven ability to adsorb and deliver a number of drugs. This research work was intended to study the suitability of modified CaP powders loaded with a fluoroquinolone as drug delivery systems for osteomyelitis treatment. Levofloxacin (LEV) was chosen due to the well-recognized anti-staphylococcal activity and adequate penetration into osteoarticular tissues. Substituted CaP powders (5mol% Sr(2+) or 5mol% Mg(2+)) were synthesised through aqueous precipitation. The obtained powders were characterised by X-ray diffraction, SEM and FTIR analysis. The X-ray diffraction patterns confirmed the presence of HA and β-tricalcium phosphates (β-TCP) phases in doped compositions, especially in the case of Mg-doped system. The fixation of LEV at the surface of the particles occurred only by physisorption. Both the in vitro microbiological susceptibility, against Staphylococcus spp, and biocompatibility of LEV-loaded CaP powders have not been compromised.

Green composites and blends from leather industry waste

Blends based on protein hydrolysate (PH), derived from waste products of the leather industry, and poly(ethylene-co-vinyl acetate) (EVA), were obtained by reactive blending and their physico-chemical properties as well as their mechanical and rheological behavior were evaluated. The effect of vinyl acetate content and of a transesterification agent added to increase interaction between polymer and bio-based components were investigated. Novel biodegradable polymeric materials for spray mulching coatings were also obtained from hydrolyzed proteins and end-functionalized poly(ethylene glycol) (PEG), which was used as crosslinking agent. These products, almost entirely obtained from renewable sources, represent a new type of biodegradable material which looks promising for several applications, for instance in packaging or in agriculture as transplanting or mulching films with additional fertilizing action of PH. POLYM. COMPOS., 37:3416–3422, 2016. © 2015 Society of Plastics Engineers

Scaffolds Based Bone Tissue Engineering: The Role of Chitosan

As life expectancy increases, malfunction or loss of tissue caused by injury or disease leads to reduced quality of life in many patients at significant socioeconomic cost. Even though major progress has been made in the field of bone tissue engineering, present therapies, such as bone grafts, still have limitations. Current research on biodegradable polymers is emerging, combining these structures with osteogenic cells, as an alternative to autologous bone grafts. Different types of biodegradable materials have been proposed for the preparation of three-dimensional porous scaffolds for bone tissue engineering. Among them, natural polymers are one of the most attractive options, mainly due to their similarities with extracellular matrix, chemical versatility, good biological performance, and inherent cellular interactions. In this review, special attention is given to chitosan as a biomaterial for bone tissue engineering applications. An extensive literature survey was performed on the preparation of chitosan scaffolds and their in vitro biological performance as well as their potential to facilitate in vivo bone regeneration. The present review also aims to offer the reader a general overview of all components needed to engineer new bone tissue. It gives a brief background on bone biology, followed by an explanation of all components in bone tissue engineering, as well as describing different tissue engineering strategies. Moreover, also discussed are the typical models used to evaluate in vitro functionality of a tissue-engineered construct and in vivo models to assess the potential to regenerate bone tissue are discussed.

Fabrication of a SFF-based three-dimensional scaffold using a precision deposition system in tissue engineering

Recent developments in tissue-engineering techniques allow physicians to treat a range of previously untreatable conditions. In the development of such techniques, scaffolds with a controllable pore size and porosity have been manufactured using solid free-form fabrication methods to investigate cell interaction effects such as cell proliferation and differentiation. In this study, we describe the fabrication of scaffolds from two types of biodegradable materials using a precision deposition system that we developed. The precision deposition system uses technology that enables the manufacture of three-dimensional (3D) microstructures. The fabrication of 3D tissue-engineering scaffolds using the precision deposition system required the combination of several technologies, including motion control, thermal control, pneumatic control and CAD/CAM software. Through the fabrication and cell interaction analysis of two kinds of scaffolds using polycaprolactone and poly-lactic-co-glycolic acid, feasibility of application to the tissue engineering of the developed SFF-based precision deposition system is demonstrated.

The Effect of Seprafilm and Interceed on Capsule Formation Around Silicone Discs in a Rat Model

The insertion of a foreign substance, such as a breast implant into mammalian soft tissues, evokes a wound healing response that culminates in a dense connective-tissue envelope or capsule surrounding the implant. Several biodegradable products, such as Seprafilm (carboxymethylcellulose and hyaluronic acid) and Interceed (oxidized regenerated cellulose), have been demonstrated to inhibit adhesions in abdominal and gynecologic surgery. The ability of these cellulose compounds to inhibit capsule formation was addressed in this investigation. Twenty-eight rats were implanted intermuscularly with either plain silicone discs (10 animals), discs wrapped in Seprafilm (10 animals), or discs covered with Interceed (8 animals). Additional control animals (6 animals) consisted of two that had sham operations, two animals implanted with Seprafilm only, and two more implanted with Interceed only. Animals were sacrificed in pairs at varying time intervals after implantation (2, 4, 8, 12, and 16 wk), and the tissues around the silicone discs were analyzed with light microscopy. Control animals were sacrificed at 8 wk. Both Interceed and Seprafilm slowed the formation of a capsule around the implanted silicone discs as both products were degraded. Evidence of residual material, presumably Seprafilm and Interceed, was seen intracellularly in animals 3 to 4 mo, respectively, after implantation. However, neither material prevented the eventual formation of a fibrous capsule around the silicone discs. The results of this study suggest that encapsulating foreign substances with these types of biodegradable materials will not significantly hinder capsule formation. A more direct attack on the wound healing mechanism may provide a definitive solution for capsule problems with implanted materials.

New types of cellulose materials obtained by an alternative spinning method

ALCERU, Lyocell, Newcell, and Tencel (the order is alphabetical and not by importance) are thus alternative hydrated cellulose fibres fabricated by a method with a low degree of harmfulness. Is this only a name or is it also a hope, as for viscose wool fibre 60 years ago? In our opinion, this is much more than only the beginning of a new generation of fibres, yarns, thin strips from film, spun articles, etc. Is this perhaps an overestimation again? No, we are convinced that this is the true path to future developments. In research on this type of processing, the goal should not be to replace natural silk, cotton, or chemical fibres, but to create a totally different type of biodegradable material fabricated with a low degree of harmfulness of the process. A multitude of requirements of modern economic development related to the operation and cost-effectiveness of production could be satisfied in this way. During development, we became convinced that fibrillation is not a defect, but instead a positive effect whose use will make it possible to discover new types of materials. And we should now be bold in using these new fibres and yarns for creating new materials. The reports from Courtaulds (Great Britain) concerning the introduction of three installations with a capacity of 50,000 tons a year each and Lenzing (Austria) concerning an installation with a capacity of 40,000 tons a year in the next three years are convincing evidence of the validity of this opinion.