An exposure system that allows large-scale exposure of animals to 1,6-hexamethylene diisocyanate (HDI)-based polyisocyanates at a stable concentration and aerosol size distribution was developed. The HDI polyisocyanate aerosol is generated by nebulizing a solution of a commercial polyisocyanate product dissolved in acetone. The aerosol is delivered with a constant airflow into a horizontal flow chamber. Complete mixing of aerosol in the chamber is ensured by a circulating fan. This method has been used to generate atmospheres containing HDI polyisocyanates at a concentration of 10.46+/-0.23 mg/m(3) over a 5-hour period. The overall mass median aerodynamic equivalent diameter was found to be 1.42 microm with a geometric standard deviation of 1.26. The HDI monomer concentration was 0.15+/-0.04 mg/m(3). The average chamber acetone concentration was determined to be 2481+/-222 ppm (mean+/-standard deviation). Different HDI polyisocyanate concentrations in the chamber can be achieved by altering the concentration of the commercial polyisocyanate product in acetone and the chamber flow rate. The described exposure system will be useful for performing toxicological studies involving HDI polyisocyanates.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1202/300.1 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
A Novel Polytetrahydrofuran-Based Shape Memory Polyurethane Enhanced by Polyglycolide-Block-Polytetrahydrofuran-Block-Polyglycolide Copolymer.
Polymers (Basel)
December 2024
State Key Laboratory of Organic-Inorganic Composites, Beijing Laboratory of Biomedical Materials, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China.
A series of polyurethanes (PU-GT) were prepared using polyglycolide-block-polytetrahydrofuran-block-polyglycolide (PGA-PTHF-PGA), polytetrahydrofuran homopolymer (PTHF), glycerol, and hexamethylene diisocyanate (HDI) by a one-pot synthesis method. The non-isothermal crystallization and subsequent heating curves showed that the PTHF component in these polyurethanes could crystallize in a temperature range of -11.5~2.
View Article and Find Full Text PDFA novel polyurethane-based silver foam dressing with superior antimicrobial action for management of infected chronic wounds.
Biomed Mater
November 2024
Department of Metallurgical and Materials Engineering, Indian Institute of Technology Ropar, Ropar, Punjab 140001, India.
Wound healing is a complex and dynamic process supported by several cellular events. Around 13 million individuals globally suffer from chronic wounds yearly, for which dressings with excellent antimicrobial activity and cell viability (>70%, as per ISO 10993) are needed. Excessive use of silver can cause cytotoxicity and has been linked to increasing antimicrobial resistance.
View Article and Find Full Text PDFDiscovery of a polyurethane-degrading enzyme from the gut bacterium of plastic-eating mealworms.
J Hazard Mater
December 2024
School of Life Science, Beijing Institute of Technology, Beijing 100081, PR China. Electronic address:
Although numerous polyurethane (PU)-degrading enzymes were identified from a diverse array of microorganisms in soil or compost, it is intriguing to investigate whether novel PU-degrading enzymes can be discovered in other biological environments. This study reports the discovery of an enzyme (MTL) for PU plastic degradation from the bacterial strain Mixta tenebrionis BIT-26, isolated from the gut of plastic-eating mealworms. MTL shows significant degradation activity towards three commercial PU substrates, including Impranil®DLN-SD, thermoplastic films (PEGA-HDI), and thermoset foams (PEGA-TDI), by cleaving the ester bonds in the polyester polyol moieties.
View Article and Find Full Text PDFAdvancing Food Packaging: Exploring Cyto-Toxicity of Shape Memory Polyurethanes.
Materials (Basel)
September 2024
Grupo de Química Macromolecular (LABQUIMAC), Departamento de Química Física, Facultad de Ciencia y Tecnología, Universidad del País Vasco UPV/EHU, CSIC, 48940 Leioa, Spain.
Cytotoxicity is a critical parameter for materials intended for biological applications, such as food packaging. Shape-memory polyurethanes (SMPUs) have garnered significant interest due to their versatile properties and adaptability in synthesis. However, their suitability for biological applications is limited by the use of aromatic isocyanates, such as methylene diphenyl 4,4'-diisocyanate (MDI) and toluene diisocyanate (TDI), which are commonly used in SMPU synthesis but can generate carcinogenic compounds upon degradation.
View Article and Find Full Text PDFRole of the Soft and Hard Segments Structure in Modifying the Performance of Acrylic Adhesives Modified by Polyurethane Macromonomers.
ACS Omega
July 2024
Shanghai Hongdingfang Science Co., Ltd, Shanghai 200237, China.
Acrylic pressure sensitive adhesives, modified by polyurethane (PU), achieve selective optimization through the designability of polyurethanes. In this paper, PU macromonomers were prepared by a two-step synthesis method, using polypropylene glycol or polyethylene glycol with different molecular weights as soft segments and different types of diisocyanates: isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethylmethane diisocyanate (HMDI), 2,4-toluene diisocyanate (TDI), and 4,4'-diphenylmethane diisocyanate (MDI) and chain extenders as hard segments. After being terminated by capping agents, a series of PU macromonomers of different molecular weights and structures were obtained and used to modify the acrylic base adhesives.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!