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1.
Int J Biol Macromol ; 265(Pt 2): 130717, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38479673

ABSTRACT

In the present study, a range of sustainable, biocompatible and biodegradable polyurethanes (PU-1 to PU-4) were synthesized using different combinations of biobased polyol (obtained through the epoxidation of soybean oil, followed by ring opening with ethanol) and polyethylene glycol (PEG) and isophorone diisocyanate. The sustainable chain extender used in this study was synthesized by the esterification of lactic acid with ethylene glycol (EG). The synthesized PU samples were characterized through scanning electron microscopy (SEM), Fourier transformed infrared (FTIR) and nuclear magnetic resonance (1H NMR and 13C NMR) spectroscopy. Wetting ability and thermal degradation analysis (TGA) of the samples were also studied. Subsequently, these PUs were examined as potential drug delivery systems using Gabapentin as a model drug, which was loaded in the polymer matrix using the solvent evaporation method. The drug release studies were carried out in 0.06 N HCl as a release medium according to the method outlined in the United States Pharmacopeia. The maximum drug release was observed for sample PU-P1, which was found to be 53.0 % after 6 h. Moreover, a comparison of different PU samples revealed a trend wherein the values of drug release were decreased with an increase in the PEG content.


Subject(s)
Polyurethanes , Soybean Oil , Polyurethanes/chemistry , Lactic Acid , Drug Delivery Systems , Chemical Phenomena , Polyethylene Glycols/chemistry
2.
Int J Prosthodont ; 37(7): 19-29, 2024 Feb 21.
Article in English | MEDLINE | ID: mdl-38489217

ABSTRACT

PURPOSE: To evaluate the effect of polymerization unit, polishing, and coffee thermocycling on the color and translucency of additively manufactured polyurethane-based resins with different viscosities. In addition, their color behavior was compared with the color of the shade tab throughout the fabrication steps and aging. MATERIALS AND METHODS: Disk-shaped specimens (Ø10 × 2 mm) were fabricated from polyurethane-based resins with different viscosities (Tera Harz TC-80DP and C&B permanent; n = 30 per material). Baseline color coordinates were measured after cleaning. The specimens in each resin group were divided into three subgroups (n = 10 per subgroup) to be polymerized with different polymerization units (Otoflash G171 [FLN], Wash and Cure 2.0 [CLED1], and P Cure [CLED2]), polished, and subjected to coffee thermocycling. Color coordinates were remeasured after each process. Color differences (ΔE00) and relative translucency parameter (RTP) values were calculated. Data were statistically analyzed (α = .05). RESULTS: Time points and polymerization units affected the ΔE00 for each material (P ≤ .049). ΔE00 of each polymerization unit pair had significant differences within and among different time points within each material (P ≤ .024). ΔE00 (when compared with the shade tab) and RTP were mostly affected by polymerization units and time points within both materials (P ≤ .042). CONCLUSIONS: Tested polymerization units, polishing, and coffee thermocycling affected the color difference and translucency of tested resins. Color differences ranged from moderately unacceptable to extremely unacceptable, and the differences in translucency values mostly ranged from perceptible to unacceptable, according to previous thresholds. In addition, tested resin-polymerization unit pairs had unacceptable color differences when compared to the shade tab. CLED1 may enable higher color stability for tested resins.


Subject(s)
Coffee , Dental Implants , Polymerization , Polyurethanes , Color , Materials Testing , Surface Properties , Composite Resins
3.
Int J Biol Macromol ; 259(Pt 2): 129237, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38191114

ABSTRACT

The discharge of crude petroleum oils and their derivatives poses serious environmental challenges, which can be mitigated through oil/water separation. In this study, polyurethane (PU)/polydopamine (PDA)/chitosan-graft (g)-octanal foam was prepared by immersing of PU foam in PDA and chitosan-g-octanal solutions. The fabricated PU foam exhibited thermal stability, flame retardancy, and hydrophobicity/superoleophilicity. The coated PU foam can selectively absorb heavy and light oils from dynamic and static oil/water mixtures. The maximum sorption capacity for olive oil was found to be as high as 41.48 g/g. PU/PDA/chitosan-g-octanal foam also demonstrated excellent flame retardancy and the ability to quickly extinguish fire, as confirmed by the limiting oxygen index (LOI) test.


Subject(s)
Aldehydes , Chitosan , Flame Retardants , Indoles , Petroleum , Polymers , Polyurethanes , Olive Oil
4.
BMC Oral Health ; 24(1): 144, 2024 Jan 31.
Article in English | MEDLINE | ID: mdl-38297268

ABSTRACT

BACKGROUND: Retainers are the only effective approach to prevent orthodontic relapse. The aim of this study was to compare the changes in color and light-transmittance of rough and smooth thermoformed polyurethane and copolymer retainer samples after staining in different solutions and destaining with different approaches. METHODS: Four hundred copolyester (Essix® ACE) and 400 polyurethane (Zendura®) samples with different surface textures, smooth and rough, were stained in 4 different solutions (n = 100 per solution) over 28 days. Each of the four groups of 100 stained samples of each material was subdivided into 5 groups of 20 samples and subjected to different destaining solutions. Light transmittance and color changes were evaluated using a spectrometer and a spectrophotometer. Mean differences were compared using a two-way analysis of variance (ANOVA) and posthoc multiple comparison tests at P = 0.05. RESULTS: No significant differences in light transmittance were found between both untreated materials. Both materials were stained in a similar fashion and showed no significant differences between two materials after staining. Coffee and tea stained both materials more significantly than wine, but there was a significant difference of changes of color and light transmittance between rough and smooth surfaces during the destaining in coffee- and tea-stained samples of copolyester material. All destaining solutions were effective at removing all stains on the samples. The surface roughness of the material plays a significant role in the ability of the materials to be destained, demonstrating a more significant greater effect on cleaning rough samples for improvements in light-transmittance and greater changes in color. CONCLUSIONS: This study concluded that the surface of materials plays a significant role in the material destaining and staining. In addition, the different polymers used for retainer fabrication exhibited different responses during the destaining process depending on types of stains.


Subject(s)
Coffee , Polyurethanes , Humans , Spectrophotometry , Staining and Labeling , Coloring Agents , Tea , Materials Testing , Color , Surface Properties , Composite Resins
5.
Strahlenther Onkol ; 200(2): 109-122, 2024 Feb.
Article in English | MEDLINE | ID: mdl-37755486

ABSTRACT

PURPOSE: Radiation-induced skin reactions remain one of the most frequent side effects of adjuvant radiotherapy for breast cancer, which is the most common global malignancy. In individual cases, we observed a decrease in radiation dermatitis under film dressings used for skin marking purposes. Therefore, we decided to revise the available evidence regarding the prophylactic use of film dressings to reduce radiation dermatitis in breast cancer patients. METHODS: On 20 March 2023, we conducted a systematic review of literature for randomized controlled trials published in the English, German, French, or Spanish language, available in the PubMed database. RESULTS: Of 82 publications, 9 full texts were assessed and 6 randomized controlled trials were included in the final synthesis. Two trials analyzed the application of polyurethane film (Hydrofilm, Paul Hartmann AG, Heidenheim, Germany), the other four of silicone-based polyurethane film (Mepitel film, Molnlycke Health Care Limited, Milton Keynes, United Kingdom). The evaluation scales Common Terminology Criteria for Adverse Events (CTCAE), Radiation Therapy Oncology Group (RTOG), and the Radiation-Induced Skin Reaction Assessment Scale (RISRAS) were used for assessment. All six trials, with a total of 788 patients yielding data for analysis, demonstrate a significant decrease in radiation-induced skin reactions by use of the film (mainly p < 0.001). CONCLUSION: Our analysis demonstrates a significant decrease in radiation-induced skin reactions by prophylactically applied film dressings in breast cancer patients. Consequent preventive use of film dressings might systematically reduce acute radiation-induced skin reactions in these patients.


Subject(s)
Breast Neoplasms , Neoplasms, Radiation-Induced , Radiodermatitis , Humans , Female , Breast Neoplasms/radiotherapy , Polyurethanes , Bandages , Breast , Radiodermatitis/etiology , Radiodermatitis/prevention & control
6.
Int J Pharm ; 649: 123618, 2024 Jan 05.
Article in English | MEDLINE | ID: mdl-37977290

ABSTRACT

Cellulose acetate phthalate (CAP)/polyvinyl alcohol (PVA)/polyurethane (PU) nanofibers were synthesized by simple and coaxial electrospinning (ES) processes. Doxorubicin (DOX) and the CoFe2O4 nanoparticles were loaded into the nanofibers. The performance of the prepared nanofibers was investigated for the sustained release of DOX against A541 lung cancer cells under chemotherapy/external magnetic field (EMF) and alternating magnetic field (AMF, hyperthermia treatment) combined methods in both the in vitro and in vivo conditions. The sustained release of DOX from core-shell nanofibers containing 5 wt% cobalt ferrite was obtained within 300, 600 h, at pH of 5.5 and 7.4 without AMF and 168, 360 h, under an alternating magnetic field (AMF). More than 98.3 ± 0.2 % of A549 cancer cells were killed in the presence of core-shell nanofibers containing 100 µg DOX and 5 % cobalt ferrite nanoparticles in the presence of AMF. The flowcytometric results indicated that only 19.1 and 8.85 % cancer cells remained alive under EMF and AMF, respectively. The in vivo results revealed in stopping the growth of tumor volume and decrease in the relative tumor volume up to 0.5 were obtained using magnetic core-shell nanofibers containing 100 µg DOX and 5 % cobalt ferrite nanoparticles in the presence of EMF and AMF, respectively.


Subject(s)
Hyperthermia, Induced , Lung Neoplasms , Nanofibers , Nanoparticles , Humans , Delayed-Action Preparations , Lung Neoplasms/drug therapy , Polyurethanes , Polyvinyl Alcohol , Cell Line, Tumor , Doxorubicin
7.
Adv Sci (Weinh) ; 11(4): e2305312, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38037312

ABSTRACT

The motion detection and thermotherapy provides a convenient strategy for the diagnosis and rehabilitation assessment of joint injuries. However, it is still challenging to simultaneously achieve accurate joint motion monitoring and on-demand thermotherapy. Herein, core-sheath sensing yarns (CSSYs) is proposed and fabricated for excellent electrical and photothermal heating, which consists of carbon black (CB)-coated nylon (sheath layer), silver-plated nylon and elastic spandex yarns (core layer). The CSSYs demonstrates great joule heating performance, which reaches 75 °C at 2 V applied voltage. The good thermal management performance can be well maintained when weaving these yarns into bifunctional smart textile. Further, the optimized double-ply CSSYs (DPCSSYs) with helically twisted structure possess several appealing sensing performance, including preferable strain sensitivity (0.854), excellent linearity (0.962), and superior durability (over 5000 cycles). The as-woven bifunctional smart textile can provide instant and convenient thermotherapy to the injured joints, and simultaneously monitor the injury and recovery conditions of the joint. Therefore, the designed bifunctional smart textile can provide a promising route for developing next-generation healthcare smart textile.


Subject(s)
Nylons , Wearable Electronic Devices , Humans , Textiles , Motion , Polyurethanes/chemistry
8.
Biomater Sci ; 12(1): 176-186, 2023 Dec 19.
Article in English | MEDLINE | ID: mdl-37955583

ABSTRACT

The development of cationic polymers that simulate antimicrobial peptides to treat bacterial infections has received much research interest. In order to obtain polymers that can not only eradicate bacteria but also inhibit biofilm formation, without inducing bacterial drug resistance, a series of cationic polymers have been developed. Despite recent progress, the chemical structures of these polymers are stable, making them recalcitrant to biodegradation and metabolism within organisms, potentially inducing long-term toxicity. To overcome this limitation, herein, a novel strategy of designing biodegradable polyurethanes with tertiary amines and quaternary ammonium salts via condensation polymerization and post-functionalizing them is reported. These polymers were found to exhibit potent antibacterial activity against Staphylococcus aureus and Escherichia coli, effectively prevent the formation of Staphylococcus aureus biofilms, act quickly and effectively against bacteria and display no resistance after repeated use. In addition, the potent in vivo antibacterial effects of these antimicrobial polyurethanes in a mouse model with methicillin-resistant Staphylococcus aureus skin infection are demonstrated.


Subject(s)
Methicillin-Resistant Staphylococcus aureus , Staphylococcal Infections , Mice , Animals , Polyurethanes/pharmacology , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Bacteria , Staphylococcal Infections/drug therapy , Biofilms , Polymers/chemistry , Microbial Sensitivity Tests
9.
BMJ Case Rep ; 16(7)2023 Jul 11.
Article in English | MEDLINE | ID: mdl-37433690

ABSTRACT

Our case describes a hospital worker who suffered a severe reaction to personal protective equipment (PPE) during the COVID-19 pandemic. After researching the excipient list of her PPE and completing a literature review, we postulated that isocyanates used in the production of the polyurethane band of the N95 mask was the cause for her reaction. In the absence of standardised testing, we tested this hypothesis by replicating her reaction to PPE by using a commercially available isocyanate patch, identifying diphenylmethane-4, 4-diisocyanate as the culprit agent.We recommended caution in the use of polyurethane containing N95 masks- for people reporting allergic reaction- and testing for sensitivity for polyurethane. The patient was able to tolerate non-polyurethane containing standard surgical masks, providing an option for PPE in some clinical circumstances. Since avoiding N95 masks, she has not had any further reactions.


Subject(s)
COVID-19 , Hypersensitivity , Female , Humans , COVID-19/prevention & control , Pandemics/prevention & control , Personal Protective Equipment/adverse effects , Masks , Hypersensitivity/etiology , Isocyanates/adverse effects , Polyurethanes
10.
Int J Biol Macromol ; 235: 123830, 2023 Apr 30.
Article in English | MEDLINE | ID: mdl-36842743

ABSTRACT

Protection coatings with self-healing ability can significantly enhance their anti-corrosion properties and service life. In this study, self-healing waterborne polyurethane (WPU) coatings with high transparence and haze were facile fabricated via cellulose nanocrystal (CNC) stabilized linseed oil (LO) Pickering emulsion. Sustainable CNCs displayed outstanding emulsifying ability and stability to stabilize LO Pickering emulsion. The size of LO Pickering emulsion droplets decreases with the CNC concentration, while the emulsion fraction and surface coverage by CNCs increase with CNC concentration, leading to a more stable Pickering emulsion. The self-healing rates of WPU coatings at varied time, temperature, CNC and catalyst concentration were investigated. Higher temperature, larger emulsion droplets, and with driers employed as catalysts generally lead to faster self-healing rate. The WPU self-healing coatings displayed much better abrasion resistance and mechanical properties than pristine WPU due to the incorporation of CNCs. Moreover, the WPU self-healing coatings show a high transparence and haze due to light scattering, and their applications as coatings of lamp covers and glass to achieve uniform light distribution and privacy protection with high light transmission were further demonstrated.


Subject(s)
Cellulose , Nanoparticles , Cellulose/chemistry , Linseed Oil , Polyurethanes , Emulsions/chemistry , Nanoparticles/chemistry
11.
Carbohydr Polym ; 302: 120313, 2023 Feb 15.
Article in English | MEDLINE | ID: mdl-36604095

ABSTRACT

In this study, tunicate cellulose nanocrystals (TCNCs) were introduced into castor oil-based waterborne polyurethane (WPU) to prepare bio-based nanocomposites through a simple solution blending method. The effect of TCNCs content on the particle size and stability of the composite dispersions, as well as the thermophysical and mechanical properties of the composite films were studied and discussed. The unique structure and properties of TCNCs, such as high crystallinity, large aspect ratio and high modulus, not only greatly improved the storage stability of WPU, but also showed significant reinforcing/toughening effects and excellent compatibility to WPU. By drip-coating silver nanowires (AgNWs) on the surface of the composite films, the flexible strain sensors were fabricated, which showed excellent sensitivity in monitoring human movement.


Subject(s)
Nanocomposites , Nanoparticles , Nanowires , Urochordata , Wearable Electronic Devices , Animals , Humans , Cellulose/chemistry , Polyurethanes/chemistry , Castor Oil/chemistry , Silver , Nanoparticles/chemistry , Nanocomposites/chemistry
12.
J Biomater Sci Polym Ed ; 34(11): 1491-1516, 2023 08.
Article in English | MEDLINE | ID: mdl-36648427

ABSTRACT

In order to produce a healing accelerator antibacterial wound dressing, different electrospun polyurethane (PU)-based nanofibers inclusive Calendula officinalis and Propolis ethanolic extracts were fabricated. The measurement of minimum inhibitory concentrations (MIC) against Methicillin-resistant Staphylococcus aureus (MRSA) determined the concentrations of incorporating extracts. Then the morphological properties of the produced polyurethane (PU), polyurethane/C. officinalis (PU/CO), polyurethane/Propolis (PU/PR), polyurethane/C. officinalis/Propolis (PU/CO/PR) were analyzed by scanning electron microscopy (SEM). The physicochemical features and biological characteristics of the fabricated nanofibers were evaluated. Subsequently, the antibacterial and wound-healing efficiency of electrospun wound dressings were tested under in vivo situation. The electrospun PU/CO/PR nanofiber illustrated the most degree of antibacterial, antioxidant, and cell proliferation efficiencies. In vivo examination and histological analysis confirmed significant improvement in the complete, well-organized wound-healing process in MRSA-infected wounds treated with PU/CO/PR. These outcomes described PU/CO/PR electrospun nanofibers as a wound dressing that can significantly facilitate wound healing with notable antibacterial, antioxidant, and cell proliferation properties.


Subject(s)
Calendula , Methicillin-Resistant Staphylococcus aureus , Nanofibers , Propolis , Propolis/pharmacology , Propolis/chemistry , Nanofibers/chemistry , Polyurethanes/chemistry , Antioxidants , Wound Healing , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry
13.
J Colloid Interface Sci ; 632(Pt A): 74-86, 2023 Feb 15.
Article in English | MEDLINE | ID: mdl-36410296

ABSTRACT

HYPOTHESIS: Materials and colloids science can provide significant contributions to the conservation of Cultural Heritage. Hybrid systems made of a castor oil-derived polymeric network and a disperse phase of zinc oxide particles (ZnO/COPs) can be more effective absorbers of acetic acid (AcOH, a major pollutant harmful to artifacts in museums and art collections) than state-of-the-art materials, provided the acid uptake mechanism by the hybrids is elucidated and optimized. The starting hypothesis was that the polymer matrix might act as transporter, while acid adsorption would take place at the ZnO particles surface. The effect of particles size was expected to play a significant role. EXPERIMENTS: The adsorption kinetics of the hybrids were studied in the 23-45˚C range, in comparison with activated charcoal, the benchmark employed by conservators. Morphological and fractal dimension of ZnO micro- and nano-particles in the hybrid networks were investigated and correlated to the adsorption kinetics. FINDINGS: The presence of a two-steps mechanism for AcOH uptake by the hybrids was demonstrated for the first time: a combination of Fickian diffusion and Case-II transport occurs in the COP matrix, and adsorption dominates acid uptake (followed by neutralization) at the particles surface. This mechanism is likely key to explain the enhanced performances of the hybrids vs activated charcoal and state-of-the-art tools to remove AcOH. The hybrids have high uptake capacity, and lower activation energies for the removal process than materials where the uptake of acid relies solely on adsorption. The size of the ZnO particles contributes to the process, i.e. nanoparticles form smaller and ramified fractal clusters that are able to adsorb AcOH more effectively than microparticles. These insights demonstrated the efficacy of the novel hybrids in art conservation, where the control of minimal concentrations of VOCs is crucial for the preventive conservation of masterpieces, and can be useful to other fields where efficient capture of acetic acid is critical (food industry, textile dyeing/printing, etc.).


Subject(s)
Castor Oil , Zinc Oxide , Acetic Acid , Polyurethanes , Adsorption , Charcoal , Polymers
14.
J Sep Sci ; 46(2): e2200661, 2023 Jan.
Article in English | MEDLINE | ID: mdl-36373185

ABSTRACT

A novel solid-phase microextraction device coated with an efficient and cheap thin film of polyurethane was developed for trace determination of 13 widely used pesticides in fruit and tea beverages. A round-shaped polyurethane film covering the bottom of a glass vial was fabricated as the sorbent to exhibit a superior capacity for preconcentrating target compounds and reducing matrix interferences. After optimization of the key parameters including the film type, extraction time, solution pH, ionic strength, desorption solvent, and conditions, this device allowed an efficient adsorption-desorption cycle for the pesticides accomplished in one vial. Coupled with gas chromatography-electron capture detection, the polyurethane-coated thin film microextraction method was successfully established and applied for the analysis of real fruit and tea drinks, showing low limits of detection (0.001-0.015 µg/L), wide linear ranges (1.0-500.0 µg/L, r2  > 0.9931), good relative recoveries (77.2%-106.3%) and negligible matrix effects (86.1%-107.5%) for the target pesticides. The proposed approach revealed strong potential of extending its application by flexibly modifying the type or size of the coating film. This study provides insights into the enrichment of contaminants from complex samples using inexpensive and reusable microextraction devices that can limit the environmental and health impact of the sample preparation protocol.


Subject(s)
Pesticides , Pesticides/analysis , Solid Phase Microextraction/methods , Polyurethanes/analysis , Fruit/chemistry , Beverages/analysis , Tea/chemistry
15.
Int J Biol Macromol ; 224: 256-265, 2023 Jan 01.
Article in English | MEDLINE | ID: mdl-36257363

ABSTRACT

Bio-based controlled release fertilizers (BCRFs) are cost-effective and renewable thus gradually replacing petroleum-based controlled release fertilizers (CRFs). However, most of the study mainly focused on modifying BCRFs to improve controlled-release performance. It is necessary to further increase the functionality of BCRF for expanding the application. A multifunctional double layered bio-based CRF (DCRF) was prepared. Urea was used as the core of fertilizer, bio-based polyurethane was used as the inner coating, and sodium alginate and copper ions formed the hydrogel as the outer coating. In addition, mesoporous silica nanoparticles loaded with sodium selenate was used to modify the sodium alginate hydrogel (MSN@Se hydrogel). The results showed that the nitrogen longevity of the DCRF was much better than that of urea and BCRF. The selenium nutrient longevity of the DCRF was 40 h, much longer than that of sodium selenate. The DCRF improved the yield and nutritive value of cherry radish (Raphanus sativus L. var.radculus pers) with the elevated contents of selenium, an essential trace element. Moreover, the DCRF showed inhibitory effect on Fusarium oxysporum Schltdl. and could resist soil-borne fungal diseases continuously. Overall, this multifunctional fertilizer has great potential for expanding the use of BCRFs for sustainable development of agriculture.


Subject(s)
Raphanus , Selenium , Polyurethanes , Fertilizers/analysis , Delayed-Action Preparations , Antifungal Agents , Selenic Acid , Soil , Nitrogen/analysis , Urea
16.
Waste Manag ; 155: 220-229, 2023 Jan 01.
Article in English | MEDLINE | ID: mdl-36399849

ABSTRACT

Waste tire rubber (WTR) has been extensively generated worldwide due to mobility needs growth. About 1.5 billion units are generated annually, constantly discharged in the environment with a few reusability alternatives. Therefore, rubber recovery methods and these residues' transformation into a cost-effective product have gained attention. Aiming to minimize the usage of fossil resources and contributes to a circular economy, it was analyzed the usage of WTR particles (5-20% by weight) in castor oil-based polyurethane foams under natural aging to promote a holistic view of all factors involved in the performance of the foams. Morphological, thermal, chemical, and mechanical properties were determined before and after exposure to open air to observe the impact of photo-oxidation and hydrolysis. The increase in viscosity of pre-polymer during the rubber loading produced greater density foams with smaller cell sizes than neat PU, in which the average cell size increased after the weathering. The rubber contributes to enhancing the compressive behavior in the non-exposed samples. After exposure, the results suggest that degradation may act to increase the crosslinking density even with the presented structural changes such as yellowing and voids. Regarding thermal stability, the rubber promotes a slight decay in the ability to resist a heat flow before and after weathering. Still, the char yield increased, showing a possibility of better fire retardancy for composites. FTIR and UV-vis showed chemical structure changes as Photo-Fries network rearrangement, Norrish I random chain scission, and Norrish II ß-scission. Besides, UV-vis revealed the maximum absorbance in the UVB region, showing that the PU reinforced by WTR can be a promising material for civil coatings.


Subject(s)
Castor Oil , Polyurethanes , Rubber , Viscosity
17.
ACS Appl Mater Interfaces ; 14(50): 56046-56055, 2022 Dec 21.
Article in English | MEDLINE | ID: mdl-36484480

ABSTRACT

Bio-based polyurethanes are promising for the controlled release of nutrients and fertilizers, but their toughness and plasticity need to be improved. We developed a smooth, dense, elastic, and indestructible bio-based polyurethane (BPU) coating with a nutrient controlled release ∼150% superior, a tensile strength ∼300% higher, and a toughness ∼1200% higher than those for the original BPU coating. Through a one-step reaction of soybean oil polyols (accounting for more than 60%), isocyanate, and benzil dioxime, the dynamic covalent network based on oxime-carbamate replaces part of irreversible covalent cross-linking. The dynamic fracture-bonding reaction in the modified coating BPU can effectively promote the hydrogen bond recombination and oxime-carbamate chain migration in the coating process, which avoids the structural defects caused by coating tear and fertilizer collision. This work provides a simple and versatile strategy for building controlled-release fertilizer coatings.


Subject(s)
Fertilizers , Polyurethanes , Polyurethanes/chemistry , Delayed-Action Preparations/chemistry , Isocyanates , Soybean Oil/chemistry
18.
J Environ Manage ; 324: 116409, 2022 Dec 15.
Article in English | MEDLINE | ID: mdl-36352715

ABSTRACT

Recently, Bio-based polyurethane controlled-release fertilizers (BPCF) have been developed rapidly owing to their environmental friendliness, renewability, and low cost. However, the unsatisfying controlled release prohibits their large-scale direct application in agricultural production. Here, we prepared bio-based controlled-release phosphate (P) fertilizers using harmful waste kitchen oils (WKO) as coating materials. The membrane shell surface was modified with multi-walled carbon nanotubes (CNT), and superhydrophobic controlled-release phosphorus fertilizers (SCRF) were obtained. After CNT modification, the controlled release period of SCRF was greatly improved. Phosphorus released period of SCRF reached over 67 d while that of BPCF was merely ∼49 d. Additionally, the surface energy, cracks, roughness, microstructure, cross-linking degree, etc., of the membrane shells were measured. The results showed that CNT greatly improved the hydrophobic properties of the membrane shells. The findings indicated the application of modified WKO with great agricultural value in preparing environment-friendly BPCFs.


Subject(s)
Fertilizers , Nanotubes, Carbon , Phosphates , Delayed-Action Preparations , Phosphorus , Polyurethanes/chemistry , Oils
19.
Int J Mol Sci ; 23(20)2022 Oct 16.
Article in English | MEDLINE | ID: mdl-36293244

ABSTRACT

In this article, rigid polyurethane foams obtained with the addition of a bio-polyol from rapeseed oil, were modified with the dimethyl propane phosphonate as additive flame retardant and two reactive flame retardants diethyl (hydroxymethyl)phosphonate and diethyl bis-(2-hydroxyethyl)-aminomethylphosphonate. The influence of used flame retardants on the foaming process and characteristic processing times of tested polyurethane systems were determined. The obtained foams were tested in terms of cell structure, physical and mechanical properties, as well as flammability. Modified foams had worse mechanical and thermal insulation properties, caused by lower cellular density and higher anisotropy coefficient in the cross-section parallel to the foam rise direction, compared to unmodified foam. However, the thermal conductivity of all tested foam materials was lower than 25.82 mW/m∙K. The applied modifiers effectively reduced the flammability of rigid polyurethane foams, among others, increasing the oxygen index above 21.4 vol.%, reducing the total heat released by about 41-51% and the rate of heat release by about 2-52%. A correlation between the limiting oxygen index values and both total heat released parameters from the pyrolysis combustion flow calorimetry and cone calorimetry was observed. The correlation was also visible between the value of the heat release capacity (HRC) parameter obtained from the pyrolysis combustion flow calorimetry and the maximum average rate of heat emission (MARHE) from the cone calorimeter test.


Subject(s)
Flame Retardants , Organophosphonates , Polyurethanes/chemistry , Rapeseed Oil , Phosphorus , Propane , Oxygen
20.
Int J Biol Macromol ; 222(Pt A): 1314-1325, 2022 Dec 01.
Article in English | MEDLINE | ID: mdl-36195223

ABSTRACT

In this work, a facile and efficient strategy known as 'dynamic self-vulcanization of dual difunctional monomers' was reported to toughen poly(lactic acid) (PLA) with in-situ formed crosslinked bio-polyurethane (PCPUE) phase from plant oil-derived hydrogenated dimer diol (Pripol) and hexamethylene diisocyanate (HDI). By simply adjusting equivalent ratios (nNCO/nOH) of complementary functional groups between these two difunctional toughening monomers from 1.0 to 2.2 while fixing their total feeding content at 20 wt%, the notched impact strength (IS) and phase morphologies of PLA blends can be tailored in a broad range. When the ratio reached 1.6, the maximum IS value up to 87.1 kJ/m2 (about 28 times that of neat PLA) was achieved with an elongation-at-break of ~223 %. Based on the analysis on reaction mechanism and phase morphologies, the optimum interfacial compatibility between PLA and PCPUE phases in junction with the proper crosslinking density of rubbery PCPUE phase was considered to be responsible for such a remarkable improvement in impact toughness.


Subject(s)
Polyesters , Polyurethanes , Polymers , Chemical Phenomena
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