Biodegradation Rate Research Articles

Effect of lignin in cellulose nanofibers on biodegradation and seed germination

AbstractPure cellulose nanofibers (CNFs) rapidly degrade in soil, limiting their prospective applications in agriculture. We incorporated lignin into CNFs as an antimicrobial and crosslinking agent to control the biodegradation rate. CNFs with different lignin concentrations were prepared by mechanochemical treatment in the presence of choline chloride-urea deep eutectic solvent. These were characterized using conductometric titration, scanning electron microscopy, and FT-IR. The fibers were applied to soil to determine the effect of lignin on soil respiration and nanocellulose degradation, and were used as a substrate for radish and cress seed germination. Modifying the lignin content of the fibers successfully modulated the biodegradation rate in soil. Fibers containing 35% lignin degraded 5.7% in 14 days, while fibers with 20% lignin degraded 20.8% in 14 days. Nanofiber suspensions showed low chemical inhibition for the germination of radish and cress seeds but higher lignin contents reduced the imbibition rate as a seed coating. This study presents the first use of lignin to control the biodegradation rate of cellulose nanofibers in a one-pot, scalable and sustainable system, allowing the advancement of lignocellulose nanofibers for applications such as seed coatings, mulches, and controlled release fertilizers. Graphical Abstract

The evolution of artificial tears based on hyaluronic acid

In recent years, there has been growing interest in the use of tear substitutes, based on natural polysaccharides in the treatment of dry eye syndrome, the leader of which is hyaluronic acid (HA). It has sufficient biocompatibility, non-immunogenicity, high viscoelasticity, hydrophilic, mucus-adhesive and good moisturizing properties. At the same time, in order to improve artificial tear preparations, there is a need to improve the mechanical and rheological properties of HA, its hygroscopicity, swelling in an aqueous environment and reducing the rate of biodegradation. One of the ways to solve this problem was the chemical modification of HA, by cross-linking its chains with two or more covalent bonds, with the participation of various polyfunctional molecules: urea, HA-cysteine ethyl ester, polyfunctional diepoxides, glutaraldehyde, carbodiimide, and many others. At the same time, the rigidity of the three-dimensional polymer network increases, increasing its resistance to enzymatic decomposition at the site of burial. Cross-linked HA has a higher viscosity compared to native hyaluronic acid due to the binding of its chains, which determines longer retention on the corneal epithelium and naturally makes it possible to reduce the frequency of drug instillations. Convincing data were obtained on the effectiveness of the resulting cross-linked hydrogel with non-Newtonian properties in vitro – on cultures of corneal epithelial cells and in vivo – on models of mechanical trauma and chemical burns of the cornea, as well as in animals with torpid corneal ulcers. The clinical effectiveness of cross-linked hyaluronic acid in the treatment of patients with dry eye syndrome of varying severity, including those due to Sjögren’s syndrome, has also been established. The higher effectiveness of cross-linked HA compared to native HA preparations has been convincingly proven. Taking into account the available information, an official drug has been developed based on cross-linked 0.2% hyaluronic acid Ocutears® Hydro+ (Santen).

Incorporating mesoporous SiO2-HA particles into chitosan/hydroxyapatite scaffolds: A comprehensive evaluation of bioactivity and biocompatibility

In this work, composite scaffolds with various composition ratios of chitosan (CS), hydroxyapatite (HA), and mesoporous SiO2 particles co-synthesized with hydroxyapatite (SiO2-HA) were fabricated via the freeze-drying method for bone tissue engineering applications. Morphological studies showed that adding mesoporous particles resulted in a structure with a more uniformly porous geometry, subsequently leading to reduced biodegradation rates and water absorption in the scaffolds. The bioactivity results showed the introduction of mesoporous particles notably enhanced the coverage of the scaffold surface with apatite films. Moreover, biocompatibility assessments using sarcoma osteogenic cell line (SAOS-2) highlighted mesoporous particles' positive impact on cell adhesion and growth. The fluorescence images showed spindle-shaped cells with a greater number and normal cell nuclei for the scaffolds containing mesoporous SiO2-HA particles. The MTT cytotoxicity results indicated that the scaffolds containing mesoporous particles showed approximately 25 % higher cell survival more than single chitosan-based ones. What is more, the mesoporous-containing scaffolds occurred to have the best alkaline phosphatase test (ALP) activity among all scaffolds. It is important to add that CS/HA/mesoporous SiO2-HA scaffolds including SAOS-2 cells showed no sign of either early or late apoptosis. These findings affirm the potential of CS/HA/mesoporous SiO2-HA scaffolds as promising implants for bone tissue engineering.

Biodegradable Zn-5Dy Alloy with Enhanced Osteo/Angio-Genic Activity and Osteointegration Effect via Regulation of SIRT4-Dependent Mitochondrial Function.

Zinc (Zn)-dysprosium (Dy) binary alloys are promising biodegradable bone fracture fixation implants owing to their attractive biodegradability and mechanical properties. However, their clinical application is a challenge for bone fracture healing, due to the lack of Zn-Dy alloys with tailored proper bio-mechanical and osteointegration properties for bone regeneration. A Zn-5Dy alloy with high strength and ductility and a degradation rate aligned with the bone remodeling cycle is developed. Here, mechanical stability is further confirmed, proving that Zn-5Dy alloy can resist aging in the degradation process, thus meeting the mechanical requirements of fracture fixation. In vitro cellular experiments reveal that the Zn-5Dy alloy enhances osteogenesis and angiogenesis by elevating SIRT4-mediated mitochondrial function. In vivo Micro-CT, SEM-EDS, and immunohistochemistry analyses further indicate good biosafety, suitable biodegradation rate, and great osteointegration of Zn-5Dy alloy during bone healing, which also depends on the upregulation of SIRT4-mediated mitochondrial events. Overall, the study is the first to report a Zn-5Dy alloy that exerts remarkable osteointegration properties and has a strong potential to promote bone healing. Furthermore, the results highlight the importance of mitochondrial modulation and shall guide the future development of mitochondria-targeting materials in enhancing bone fracture healing.

Accelerating Biodegradation: Enhancing Poly(lactic acid) Breakdown at Mesophilic Environmental Conditions with Biostimulants.

Poly(lactic acid) (PLA) has garnered interest due to its low environmental footprint and ability to replace conventional polymers and be disposed of in industrial composting environments. Although PLA is compostable when subjected to a suitable set of conditions, its broader acceptance in industrial composting facilities has been affected adversely due to longer degradation timeframes than the readily biodegradable organic waste fraction. PLA must be fully exposed to thermophilic conditions for prolonged periods to biodegrade, which has restricted its adoption and hindered its acceptance in industrial composting facilities, negating its home composting potential. Thus, enhancing PLA biodegradation is crucial to expand its acceptance. PLA's biodegradability is investigated in a compost matrix under mesophilic conditions at 37 °C for 180 days by biostimulating the compost environment with skim milk, gelatin, and ethyl lactate to enhance the different stages of PLA biodegradation. The evolved CO2, number average molecular weight (Mn), and crystallinity evolution are tracked. To achieve a Mn ≲ 10kDa for PLA, the biodegradation rate is accelerated by 15% by adding skim milk, 25% by adding gelatin, and 22% by adding ethyl lactate. This work shows potential techniques to help biodegrade PLA in home composting setting by adding biostimulants.

Diesel−biodegradation and biosurfactant−production by Janthinobacterium lividum AQ5-29 and Pseudomonas fildesensis AQ5-41 isolated from Antarctic soil

Given the substantial diesel demand in Antarctic operations, the means of addressing ecological restoration following its inappropriate release are attracting attention from researchers. The Madrid Protocol mandates the use of indigenous microbes in bioremediation. Recent studies have proposed many native isolates with biodegradation temperatures exceeding 20 °C, which are impractical for Antarctic contexts. Therefore, harnessing psychrophilic, native degraders with biosurfactant−producing traits presents an advantage for implementation in the harsh Antarctic environment. In this study, effective consortia/isolates demonstrated robust growth and biodegradation rates at 10 °C with diesel as the sole carbon source. Two primary bacterial members, Janthinobacterium lividum and Pseudomonas fildesensis, were identified from the most effective consortium SI 20 using 16S rRNA and multilocus−sequence−analysis (MLSA) clustering. The degraders were characterised as being psychrophilic, Gram-negative, rod−shaped, and catalase− and oxidase−positive. Despite the observed antagonistic effects during co-cultivation, strains J. lividum AQ5-29 and P. fildesensis AQ5-41 demonstrated effective diesel removal (2.91 & 4.20 mg mL−1) with biodegradation of C10 to C30 hydrocarbons (40−100%) at 10 °C in less than 8 days. Both strains also were identified as biosurfactant producers with varying emulsification activities (32−92%) and cell surface hydrophobicity (52−58%). These findings highlight the potential of both strains for restoring diesel-related substrates, particularly in Antarctica.

Impact of fiber coating with hydrophobic nanoparticles polymer on the physicomechanical properties of Pisum sativum L. fibers/ styrene butadiene rubber ecofriendly composites

Hydrophobic nanoparticle copolymers of vinyl acetate and different ratios of veova10 were used to coat Pisum sativum L. fibers (PSF). The impact of coating process on the reinforcement efficiency of PSF of styrene butadiene rubber (SBR) was investigated. The morphology study, indicated that, the coating with hydrophobic nanoparticle copolymers improved the interfacial adhesion between the PSF and SBR. The tensile strength (TS) of the composites containing coated fibers recorded the highest tensile properties, the lowest Mullins effect and the highest resistance to water absorption. The coating process improved the TS of PSF/SBR composite up to 35.3% after incorporation of 10 phr of coated PSF. The PSF/SBR composite containing 20 phr of coated fibers recorded water uptake of 14.18% compared to 23.24% for composites containing uncoated fibers. The PSF/SBR composites exhibited more biodegradation rate than that of neat SBR. The results indicated that the PSF coated with the prepared hydrophobic polymers had a beneficial impact on the physicomechanical properties of the PSF/SBR composites.

Flexible, Biodegradable, and Wireless Magnetoelectric Paper for Simple In Situ Personalization of Bioelectric Implants.

Bioelectronic implants delivering electrical stimulation offer an attractive alternative to traditional pharmaceuticals in electrotherapy. However, achieving simple, rapid, and cost-effective personalization of these implants for customized treatment in unique clinical and physical scenarios presents a substantial challenge. This challenge is further compounded by the need to ensure safety and minimal invasiveness, requiring essential attributes such as flexibility, biocompatibility, lightness, biodegradability, and wireless stimulation capability. Here, a flexible, biodegradable bioelectronic paper with homogeneously distributed wireless stimulation functionality for simple personalization of bioelectronic implants is introduced. The bioelectronic paper synergistically combines i) lead-free magnetoelectric nanoparticles (MENs) that facilitate electrical stimulation in response to external magnetic field and ii) flexible and biodegradable nanofibers (NFs) that enable localization of MENs for high-selectivity stimulation, oxygen/nutrient permeation, cell orientation modulation, and biodegradation rate control. The effectiveness of wireless electrical stimulation in vitro through enhanced neuronal differentiation of neuron-like PC12 cells and the controllability of their microstructural orientation are shown. Also, scalability, design flexibility, and rapid customizability of the bioelectronic paper are shown by creating various 3D macrostructures using simple paper crafting techniques such as cutting and folding. This platform holds promise for simple and rapid personalization of temporary bioelectronic implants for minimally invasive wireless stimulation therapies.

An overview on trehalolipids: a promising eco-friendly bio-surfactant

Abstract Amphiphilic surfactants, which are currently used mainly for cleaning purposes, are produced in large quantities from petroleum, but are often harmful to the environment and poorly biodegradable. Therefore, the importance of environmentally friendly, non-toxic and skin-friendly biosurfactants is increasing. Different types of biosurfactants exist depending on their molecular structure. Trehalolipids belong to the low molecular weight glycolipids. Compared to other microbial glycolipids, they often show different properties and performances, including inhibition and enhancement of biodegradation rates. Optimisation of their production and downstream processing is one of the major obstacles to the potential use of trehaloselipids in a range of applications. This review provides an overview of different substrates and microorganisms used for trehalose lipid production, as well as various applications in bioremediation, biomedicine and microbial enhanced oil recovery.

Platelet gel and factors determining its biological activity

A platelet gel (PG) derived from platelet concentrate (PC) is considered as a perspective therapeutic agent with hemostatic and regenerative properties. PG was obtained from PC separated from human peripheral blood by automatic apheresis by adding human thrombin (30 U/ml). We compared the proliferation of human mesenchymal stromal cells (MSCs) in vitro in the presence of PG and the dependence of gel density on excess of fibrinogen, the presence of calcium chloride, calcium gluconate, and aprotinin. PG was formed from CT in the presence of thrombin during 5–10 minutes. PG as gel-like fibrin membrane contained platelets and an admixture of leukocytes, and was capable to enhance the proliferation of MSCs in vitro. The presence of calcium gluconate (10 mg/ml) increased in the presence of PG the rate of MSCs proliferation in vitro. The presence of aprotinin in PG at a concentration of 10–1000 KIU/ml caused a dose-dependent decrease in the rate of gel biodegradation and did not affect the ability of PG to stimulate the proliferation of human MSCs in vitro.

On‐Patient Temporary Medical Record for Accurate, Time‐Sensitive Information at the Point of Care

AbstractAccurate medical recordkeeping is important for personal and public health. Conventional forms of on‐patient medical information, such as medical alert bracelets or finger‐markings, may compromise patient privacy because they are readily visible to other people. Here, the development of an invisible, temporary, and easily deployable on‐patient medical recordkeeping system is reported. Information is stored in unique patterns of spatially distributed near‐infrared (NIR) fluorescent quantum dots (QDs), which are delivered to the skin using dissolvable microneedle arrays. The patterns are invisible to the naked eye but detectable with an infrared camera, which can extract information with >98% accuracy using automated pattern recognition software. By encapsulating NIR QDs in an FDA‐approved biodegradable polymer, biodegradation rates can be tuned so that the encoded medical information can be conveyed in both a spatial and temporal manner, with some components fading within 100 days and others persisting for 6 months. This may be particularly useful for administering a series of vaccinations or treatments by indicating if enough time has passed for the patient to receive the next dose. Importantly, this system contains no personal information, does not require connection to a centralized database, and is not visible to the naked eye, ensuring patient privacy.

Plant and yeast consortium for efficient remediation of dyes and effluents: a biochemical and toxicological study.

Textile effluent carries a range of dyes that may be recalcitrant and resistant to biodegradation. A unique consortium of the Fimbristylis dichotoma and Saccharomyces cerevisiae is exploited for the biodegradation of an azo dye Rubine GFL and actual textile effluent. This consortium enhances the rate of biodegradation of Rubine GFL and actual textile effluent with an excellent rate of biodegradation of 92% for Rubine GFL and 68% for actual textile effluent when compared to the individual one within 96 h. Speedy decolorization of Rubine GFL and actual textile effluent was observed due to the induction of oxido-reductive enzymes of the FD-SC consortium. Along with the significant reduction in the values of COD, BOD, ADMI, TSS, and TDS with 70, 64, 65, 41, and 52%, respectively, in experimental sets treated with FD-SC consortium. The biodegradation of Rubine GFL was confirmed with UV-Vis spectroscopy at the preliminary level, and then, metabolites formed after degradation were detected and identified by FTIR, HPLC, and GC-MS techniques. Also, decolorization of the dye was observed in the sections of the root cortex of Fimbristylis dichotoma. The toxicity of dye and metabolites formed after degradation was assessed by seed germination and bacterial count assay, where increased germination % and bacterial count from31×107CFUsto 92 × 107 CFUs reflect the nontoxic nature of metabolites. Furthermore, the nontoxic nature of metabolites was confirmed by fish toxicity on Cirrhinus mrigala showed normal structures of fish gills and liver in the groups treated with FD-SC consortium proving the better tactic for biodegradation of dyes and textile effluent.

Biocompatibility and features of degradation of polymer anti-adjection membranes with antibacterial activity

When performing operations on the abdominal and thoracic organs, the main share of postoperative complications is represented by the formation of adhesions or the development of an infectious process, which leads to a decrease in the quality of life of patients, the need for reoperation and often causes deaths. A solution to this problem can be the use of intraoperative biodegradable anti-adhesion membranes that have their own antibacterial activity.Aim. Development of polymer anti-adhesion membranes with their own anti-inflammatory and antibacterial activity, assessment of their biocompatibility and biodegradation in in vivo experimentsMaterials and Methods. The membranes are made by electrospinning from a composition of biodegradable polymers: polylactide-co-glycolide copolymer (50:50) and polylactide-co-glycolide (85:15). To impart antibacterial properties to the membrane, the antibiotic Tigacil was added to the polymer solution in various dosages - 0.125; 0.25 and 0.5 mg/ml polymer solution. The antibacterial activity of the membranes in vivo was assessed. The physical and mechanical properties were studied and the surface structure of the membranes was assessed using a scanning electron microscope. Biocompatibility and dynamics of biodegradation were assessed in vivo by implantation into laboratory animals (rats) for periods of 14 days, 1, 2 and 3 months, followed by histological examination of explanted samples.Results. Polymer membranes made by electrospinning, without the inclusion of Tigacil, consist of threads whose thickness was 1.63 microns (1.422.85 microns); when Tigacil is included in the fiber composition, the fiber thickness decreases to 1.2 microns (0.977 - 1.89 pm), while the threads are more densely and orderly located. The strength and elasticity modulus of membranes with Tigacil are almost 2 times higher than those of samples without the inclusion of the drug. The maximum antibacterial effect was achieved at a Tigacil dosage of 0.5 mg/ml - the zone of inhibition of Staphylococcus aureus at a Tigacil concentration of 0.125 mg/ ml was 146%, 0.25 mg/ml - 152% and at a concentration of 0.5 mg/ml - 11 .5 mm 177%. The inclusion of Tigacil led to a decrease in the rate of biodegradation of samples in vivo. The samples underwent biodegradation without signs of acute and chronic inflammation.Conclusion. The inclusion of Tigacil in the membrane gives it antibacterial properties, and the optimal concentration of Tigacil was 0.5 mg/ml of the polymer solution. The inclusion of Tigacil in the polymer composition affects the morphology of the membranes, increases the strength and elastic modulus, which led to a decrease in the rate of degradation when implanted subcutaneously in rats. The absence of signs of inflammation confirms the biocompatibility of the developed membranes.

Synthesis and Characterization of Bioplastic Derived from Chlorella sp. Residue Biomass

The accumulation of plastic waste is a significant global pollution issue in the age of globalization. Despite their irreplaceable properties and multiple applications, conventional fossil-based plastics cannot decompose naturally in the environment, resulting in exponential accumulation over time. To address this problem, biodegradable and biobased plastics have been introduced as alternatives to fossil-based plastics. This study aimed to characterize bioplastics formulated from <i>Chlorella</i> sp. microalgae biomass. Various formulations of biodegradable plastics were developed using microalgae <i>Chlorella</i> sp. and tapioca starch, with varying levels of plasticizer glycerol or sorbitol (25 wt%, 50 wt%, or 75 wt% based on the weight of starch) and the addition of chitosan as a filler. The physical, mechanical, and chemical properties of bioplastics were characterized. The study found that the chlorella bioplastics were ductile and had low elasticity, despite the addition of glycerol or sorbitol. However, the bioplastic exhibited an exceptional rate of biodegradability, with 100% weight loss when buried in loamy soil for 7 days. Furthermore, the <i>Chlorella </i>bioplastic with 75 wt% of glycerol, without the addition of chitosan, exhibited the highest solubility at 62.35%. The results indicated that increasing the amount of plasticizer tended to increase solubility, with glycerol having a more significant effect than sorbitol. Meanwhile, chitosan loading reduced bioplastic solubility.

Evaluation of properties of biodegradable wood-polymer composite based on ozonized wood filler and polyhydroxybutyrate for application in agricultural industry

The aim of this work is to develop a biodegradable planting container based on a wood-polymer composite made from polyhydroxybutyrate (PHB) and modified wood flour. To obtain a product with a given biodegradation rate, a filler is introduced into the polymer matrix in a ratio that provides the required mechanical strength. In the work were conducted experimental studies to determine the tensile strength and bending strength, impact toughness and a study to determine the rate of biodegradation of samples. The results of the studies showed that preliminary ozonization of wood flour allows to introduce into the composite up to 50% of wood filler from the total mass of the composition without loss of its mechanical properties.

Efficiency of aerobic biodegradation of sugar beet distillery stillage under dissolved oxygen tension-controlled conditions.

The efficiency of aerobic biodegradation of distillery wastewater using various microbial cultures is intricately linked to process conditions. The study aimed to examine the aerobic biodegradation by a Bacillus bacteria under controlled dissolved oxygen tension (DOT) conditions as a novel approach in the treatment of sugar beet distillery stillage. The processes were conducted in a 2-L Biostat®B stirred-tank reactor (STR), at a temperature of 36°C, with aeration of 1.0 L/(L·min), and uncontrolled pH of the medium (an initial pH of 8.0). Each experiment was performed at a different DOT setpoint: 75%, 65% and 55% saturation, controlled through stirrer rotational speed adjustments. The study showed that the DOT setpoint did not influence the process efficiency, determined by the pollutant load removal expressed as COD, BOD5 and TOC. In all three experiments, the obtained reduction values of these parameters were comparable, falling within the narrow ranges of 78.6-78.7%, 97.3-98.0% and 75.0-76.4%, respectively. However, the DOT setpoint did influence the rate of process biodegradation. The removal rate of the pollutant load expressed as COD, was the lowest when DOT was set at 55% (0.48 g O2/(L•h)), and the highest when DOT was set at 65% (0.55 g O2/(L•h)). For biogenic elements (nitrogen and phosphorus), a beneficial effect was observed at a low setpoint of controlled DOT during biodegradation. The maximum extent of removal of both total nitrogen (54%) and total phosphorus (67.8%) was achieved at the lowest DOT setpoint (55%). The findings suggest that conducting the batch aerobic process biodegradation of sugar beet stillage at a relatively low DOT setpoint in the medium might achieve high efficiency pollutant load removal and potentially lead to a reduction in the process cost.

Effect of elastic filler on the treatment effect and archaea community structure of ABR

This research endeavored to elucidate the influence of elastic fillers on the performance and archaeal community configuration of the Anaerobic Baffled Reactor (ABR). Utilizing high-throughput sequencing technology, the archaeal community structure was assessed in two distinct ABR sets. The findings revealed that the introduction of elastic fillers led to an enhancement in the average COD removal rate, BOD5 removal rate, effluent biodegradability, and fecal coliform removal rate of the ABR by 3.55%, 3.02%, 7.45%, and 96.85% correspondingly. Concurrently, it facilitated the transformation and degradation of organic matter within the ABR, thus resulting in an increased conversion of organic matter into Volatile Fatty Acids (VFA) within the initial compartment, and enhanced VFA degradation in the subsequent compartments. Indices such as Chao1, Observed species, Simpson, and Shannon concurred that the abundance and heterogeneity of the archaeal community within the ABR were augmented. The average relative abundance of dominant archaea (Methanosaeta and Methanobacterium) in the first compartment of ABR diminished by 3.44%, whereas in the second, third, and fourth compartments, the abundance escalated by 10.50%, 4.18%, and 2.78% respectively. The inclusion of elastic fillers not only amplified the hydrolysis and acid production process in the first compartment of the ABR but also fostered the methane production process in the subsequent compartments.

Star-PCL shape memory polymer (SMP) scaffolds with tunable transition temperatures for enhanced utility.

Thermoresponsive shape memory polymers (SMPs) prepared from UV-curable poly(ε-caprolactone) (PCL) macromers have the potential to create self-fitting bone scaffolds, self-expanding vaginal stents, and other shape-shifting devices. To ensure tissue safety during deployment, the shape actuation temperature (i.e., the melt transition temperature or Tm of PCL) must be reduced from ∼55 °C that is observed for scaffolds prepared from linear-PCL-DA (Mn ∼ 10 kg mol-1). Moreover, increasing the rate of biodegradation would be advantageous, facilitating bone tissue healing and potentially eliminating the need for stent retrieval. Herein, a series of six UV-curable PCL macromers were prepared with linear or 4-arm star architectures and with Mns of 10, 7.5, and 5 kg mol-1, and subsequently fabricated into six porous scaffold compositions (10k, 7.5k, 5k, 10k★, 7.5k★, and 5k★) via solvent casting particulate leaching (SCPL). Scaffolds produced from star-PCL-tetraacrylate (star-PCL-TA) macromers produced pronounced reductions in Tm with decreased Mnversus those formed with the corresponding linear-PCL-diacrylate (linear-PCL-DA) macromers. Scaffolds were produced with the desired reduced Tm profiles: 37 °C < Tm < 55 °C (self-fitting bone scaffold), and Tm ≤ 37 °C (self-expanding stent). As macromer Mn decreased, crosslink density increased while % crystallinity decreased, particularly for scaffolds prepared from star-PCL-TA macromers. While shape memory behavior was retained and radial expansion pressure increased, this imparted a reduction in modulus but with an increase in the rate of degradation.

Effect of Biostimulation on Biodegradation Rate of Hydrocarbon-Polluted Soil: A Review

Effect of Biostimulation on Biodegradation Rate of Hydrocarbon-Polluted Soil: A Review

Preparation and characterization of amphiphilic, biodegradable, waterborne polyurethanes without using organic solvent and catalyst.

Traditionally, waterborne polyurethanes (WPUs) are prepared using toxic organic solvents and catalysts. These WPUs are non-biodegradable and are buried or incinerated after the expiration date. This has adverse effects on the environment and human health, which limits the applications of WPUs. Herein, a special synthetic method was developed for biodegradable waterborne polyurethane (BWPU) by adding hydrophilic prepolymers into WPU prepolymers without using organic solvents and catalysts. Different proportions of polyethylene glycol (PEG) were introduced into polycaprolactone (PCL)-based BWPUs to improve the comprehensive properties. Results showed that as the PEG content was increased from 0 to 16 wt%, the solid content of BWPU increased from 34.8 wt% to 53.1 wt%, while the tensile strength and Young's modulus of BWPU films increased from 21.81 MPa to 56.83 MPa and 8.08 MPa to 19.4 MPa, respectively. However, the elongation at break did not decrease significantly, but still reached 827.17%. With an increase in PEG content, the crystallinity and phase separation decreased, while the hydrophilicity and surface energy increased for BWPU films. In addition, the prepared BWPUs had good biodegradability in PBS/lipase solution. The mass loss of BWPU without PEG reached 6.3 wt% after 4 weeks of degradation, whereas the mass losses of BWPUs with PEG reached 2.3-4.3 wt%. Obviously, the introduction of PEG did not increase biodegradability. Thus, the higher the PCL content, the faster the biodegradation rate. This work would provide an effective method for the preparation of ecofriendly biodegradable BWPU with excellent comprehensive properties.