Polyurethane

As a new class of luminescent nanomaterials, carbon dots (CDs) have aroused significant interest because of their fascinating photoluminescence properties and potential applications in biological, optoelectronic, and energy-related fields. Strikingly, embedding CDs in host matrices endow them with intriguing luminescent properties, in particular, room temperature phosphorescence and thermally activated delayed fluorescence, due to the confinement effect of the host matrix and the H-bonding interactions between CDs and the matrix...

Creating stretchable and transparent conductive electrodes for stretchable and transparent electronics is very challenging due to difficulties in obtaining adequate optical and mechanical properties simultaneously. Here, we designed a stretchable and transparent nanofiber-networked electrode (STNNE) based on a networked structure of electrospun stretchable nanofibers made from a mixture of polyurethane (PU)/reduced graphene oxide (rGO)/silver nanoparticles (AgNPs). The STNNE showed a sheet resistance as small as 210 Ω sq-1 at an optical transparency of ∼83%...

Occupational asthma and allergic diseases of the upper airway play an important role in occupational diseases. The most frequent allergens, which causes occupational respiratory diseases in the Czech Republic, are isocyanates and wheat and rye flour. Isocyanates are the substances used in car industry during production of polyurethanes, they are in colours and glues. Occupational allergic asthma and rhinitis are diagnosed using specific challenge tests with substances from the workplace. These tests can be done in a special exposure box in a lab with substances taken by hygiene specialists from the patient´s workplace or using direct exposure at the workplace...

In recent years, noise has become a serious hazard and can have permanent biological and psychological effects on humans and other organisms in nature. Textile materials are commonly used as absorbent acoustic materials for noise reduction. This work examines the use of electrospun nylon-6 and polyurethane nanofibres (PU NFs) to improve the sound absorption and sound insulation properties of polyurethane foam. In this work, nylon-6 and polyurethane nanofibres were prepared by an electrospinning technique and were glued to a polyurethane foam...

In this study, novel elastomeric biodegradable bone regenerative films were developed from metformin (Met) and polyurethane (PU). Metformin was selected due to its osteogenic properties and proper chemical structure to react with PU prepolymer. Metformin was integrated into PU macromolecular structure as chain extender after the synthesis of PU prepolymer via condensation polymerization of polycaprolactone diol and hexamethylene diisocyanate. Chemical, thermal, viscoelastic properties of PU-Met films where characterized and discussed in terms of structure-property relationships...

The development of infection resistant materials is of substantial importance as seen with an increase in antibiotic resistance. In this project, the nitric oxide (NO)-releasing polymer has an added topcoat of zinc oxide nanoparticle (ZnO-NP) to improve NO-release and match the endogenous NO flux (0.5 - 4 x 10-10 mol cm-2 min-1 ). The ZnO-NP is incorporated to act as a catalyst and provide the additional benefit of acting synergistically with NO as an antimicrobial agent. The ZnO-NP topcoat is applied on a polycarbonate-based polyurethane (CarboSil) that contains blended NO donor, S-nitroso-N-acetylpenicillamine (SNAP)...

The distinctive ability to remember their original form after partial or complete deformation makes shape memory polymers remarkable materials for several engineering and biomedical applications. In the present work, the development of a polycaprolactone based toughened shape memory polyurethane biocomposite promoted by in situ incorporation of chitosan flakes has been demonstrated. The chitosan flakes were homogeneously present in the polymer matrix in the form of nanoflakes, as confirmed by the electron microscopic analysis and probably developed a crosslinked node that promoted toughness ( a > 500% elongation at break) and led to a ~130% increment in ultimate tensile strength, as analyzed using a universal testing machine...

In recent years, lead halide perovskite nanocrystals (NCs) have attracted significant attention in both fundamental research and commercial applications due to their excellent optical and optoelectrical properties. However, the protective ligands on the surface of the perovskites NCs could be easily removed after the tedious process of centrifugation, separation, and dispersion, which greatly hampers their stability against light, heat, moisture, and oxygen and limits their practical applications. Here we report a new post-processing-free strategy (i...

PURPOSE: Nasal bone fracture reduction surgery is normally followed by nasal packing to control bleeding. Yet, patients suffer from pain and require further analgesic treatments following nasal packing and removal. This study aimed to evaluate the effect of fentanyl-soaked packing as a method of controlling pain after nasal surgeries in a prospective, randomized, double-blind controlled trial. METHODS: Sixty-five patients that have undergone closed nasal bone fracture reduction surgery were included in this study...

Focusing on eco-friendly materials, cellulose nanocrystal (CNC) extracted from office waste paper was used to reinforce waterborne polyurethane (WPU) with varying content by two incorporation routes including blending method by sonication after WPU synthesis (BCNC/WPU) and the alternative in-situ during the WPU synthesis process (CNC/WPU). The results showed that new interaction between CNC and WPU through hydrogen bonds in the interfacial area was formed and CNC reinforced hard segments effectively. However, the interaction in BCNC/WPU was not as stronger as that in CNC/WPU...

We demonstrated a novel mixed matrix composite membrane (MMCM) based on acrylated polyurethane (APU) and UiO-66 nanoparticles to separate CO2/N2 mixture. UiO-66 and functionalized UiO-66 including NH2-UiO-66 and GMA-UiO-66 were loaded in APU/HEMA (APUH) matrix at variable concentrations between 3-30 wt%. APUH/ GMA-UiO-66s MMCM exhibited strong adhesion with support layer of polyester/polysulfone (PS/PSF) which was not deteriorated after immersion in water for a long time (20 days). Incorporation of UiO-66 and its functionalized forms increased simultaneously permeability and CO2/N2 selectivity which was indeed superior in comparison with MMCMs reported previously...

The literatures about superhydrophobic coatings (SHCs) are increasing every year, however, undesirable chemicals including organic solvents and fluorinated compounds are intensively used in the existing preparation methods, which seriously hinder their large scale production and practical applications. Herein, a simple approach for preparation of totally waterborne, fluorine-free and durable SHCs is reported. First, a waterborne suspension of hexadecyl polysiloxane modified SiO2 (SiO2 @HD-POS) was prepared via HCl-catalyzed hydrolytic condensation of hexadecyltrimethoxysilane (HDTMS) and tetraethoxysilane with SiO2 nanoparticles...

In order to control bacterial adhesion and metal corrosion in the circulating cooling water system, it is necessary to prepare a nanocomposite-modified coating with antibacterial and anticorrosive functions. Copper and zinc composite oxide (CuZnO) was synthesized to prepare CuZnO@RGO nanocomposites. The antibacterial mechanism of CuZnO@RGO nanocomposites was investigated using gram-negative bacteria E. coli and gram-positive bacteria S. aureus as the two model microorganisms. The antibacterial properties of CuZnO@RGO nanocomposites on mixed bacteria were researched in the cooling water system...

Superhydrophobic nanomaterials are promising in the important pursuit to alleviate the environmental pollution caused by the petroleum crude oil industry, especially to clean-up oil spills. In this work, asphaltenes isolated from crude oil were modified to act as capping agents during the synthesis of hydrophobic silica nanoparticles (HSNPs). The chemical structure, surface morphology, particle size, and surfaces charge of HSNPs were investigated. The contact angles of water droplets on HSNP film surfaces were measured to investigate their wetting properties...

This study reviewed the early use of polyurethane for total knee resurfacing, the long-term results of polycarbonate urethane (PCU) for total knee replacement and conducted wear simulator testing of PCU. In 1959 and 1960, 10 patients underwent total articular polyurethane knee replacement (polyethylene was not available). The polyurethane was placed on the articular surface of the femur with metal surfaces on the tibia and patella. In 1996 and 1997, four patients received a newer PCU tibial insert in revision procedures; all had well-fixed prostheses, but no revision polyethylene implants were available...

This article aims to present an overview on the use of polyurethane (PU) breast implants and the possible association with the risk of developing breast implant-associated anaplastic large cell lymphoma (BIA-ALCL), with a special look at the current situation in Europe. It is well known that the real cause of BIA-ALCL remains unknown. Although this is a rare disease, many interesting theories surrounding its development have been advanced; however, none of these theories has been able to demonstrate with statistical significance, as required by the criteria of evidence-based medicine, definitive clinical proof as to why BIA-ALCL develops...

The design and analysis of a device to measure the burst strength (strength under a state of pure radial internal pressure) and compliance of vascular grafts and flexible pressurized tubes is presented. The device comprises three main sections, viz., a clean air-dry pressure controller, a test specimen holder, and automated software for control and data collection. Air pressure is controlled by means of a valve and a dedicated mechanism allowing reaching up to 120 psi in increments of 1 psi, and recording pressure changes with 0...

Polyurethane foam (PUF) disks in passive air samplers (PAS) and passive dry deposition (Pas-DD) collectors were used to assess the presence of persistent organic pollutants (POPs) and current-use pesticides (CUPs) in a rural area of central Chile (Peumo, VI Region). The samplers were exposed from September 2015 (spring) to March 2016 (summer), with the PUFs collected at intervals of 30, 60 and 90 days. Both samplers (PUF-PAS and Pas-DD) captured more than one pesticide per sampling period. Chlorpyrifos-ethyl and pyrimethanil presented the highest air concentration with PUF-PAS (3470...

Background: Guidelines recommend foot orthoses for people with both early (< 2 years) and established rheumatoid arthritis (RA). While prefabricated foot orthoses are cheaper and can exhibit comparable effects to customised devices, the available evidence for their effectiveness is inconsistent. Little is known about what types of foot orthoses clinicians prescribe. This study describes the foot orthoses prescription habits of podiatrists for people with rheumatoid arthritis. Methods: One hundred and eighty-three podiatrists from the United Kingdom (UK) ( n  = 88), Australia ( n  = 68) and New Zealand ( n  = 27) completed a self-administered, online survey regarding the types of foot orthoses prescribed in clinical practice for people with RA...

OBJECTIVES: The clinical experience with tissue-engineered tracheal grafts (TETGs) has been fraught with graft stenosis and delayed epithelialization. A mouse model of orthotopic replacement that recapitulates the clinical findings would facilitate the study of the cellular and molecular mechanisms underlying graft stenosis. METHODS: Electrospun nanofiber tracheal scaffolds were created using nonresorbable (polyethylene terephthalate + polyurethane) and co-electrospun resorbable (polylactide-co-caprolactone/polyglycolic acid) polymers (n = 10/group)...