A novel dispersion polymerization system, with a methanol/water (MeOH/H2O) mixture as reaction medium and a polymerizable dimethylaminomethacrylate methyl chloride (DMC) as stabilizer was developed. By monitoring the polymerization evolution and observing the morphological changes of the polystyrene (PS) particles by SEM, it was found that this system had the following unique features: (1) a much lower amount of DMC (0.025 mass% based on styrene as opposed to 5 mass% for a routine system) was required to prepare monodisperse and stable PS particles; (2) the rate of polymerization was fast and the conversion was very high; (3) the monodisperse particles with average diameters of approximately 200-1600 nm could be directly obtained. These features were explained by a synergistic interaction between water and the quarternary ammonium cations. Combined with XPS, ion-exchange/conductometric titration, FTIR and 1H NMR analysis, a plausible polymerization mechanism through which the particles were stabilized by the PS-PDMC copolymer formed in situ was proposed.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.jcis.2009.02.040 | DOI Listing |
Langmuir
January 2025
School of Chemistry, Key Centre for Polymers and Colloids, The University of Sydney, Sydney, New South Wales 2006, Australia.
Polymer Janus nanoparticles with one hard cross-linked polystyrene lobe and one soft film-forming poly(methyl methacrylate--butyl acrylate) lobe were synthesized by reversible addition-fragmentation chain transfer (RAFT)-mediated emulsion polymerization. The Janus nanoparticles adsorbed to oil/water and air/water interfaces, where the soft lobes coalesced, forming films of thickness between 25 and 250 nm; droplets of silicone oil could be stably encapsulated in polymer in this way. When prepared by mechanical mixing without additives, capsules of diameter 5-500 μm could be prepared, and with additives and application of heat, capsules of diameter around 5 μm were achieved, even with highly viscous silicone oil (20,000 cSt).
View Article and Find Full Text PDFEnviron Sci Technol
January 2025
Stockbridge School of Agriculture, University of Massachusetts, Amherst, Massachusetts 01003, United States.
Concern over nanoplastic contamination of wetland ecosystems has been increasing. However, little is known about the effect of photoaging on the distribution and biological response of the nanoplastics. Here, palladium-labeled polystyrene nanoplastics (PS-Pd NPs) at 0.
View Article and Find Full Text PDFJ Hazard Mater
January 2025
State Key Laboratory of Marine Food Processing and Safety Control, Dalian Polytechnic University, Dalian, Liaoning 116034, PR China. Electronic address:
The existence of ochratoxin A (OTA) in agricultural products poses significant threats to human health and environment, underscoring the critical need for its prompt and precise quantification. A particle counting immunosensor for the highly sensitive detection of OTA was presented, employing SiO@CuO nanoparticles to facilitate click chemistry. The quantity of SiO@CuO nanoparticles, and consequently the Cu²⁺ concentration, can be directly altered through the immune response involving OTA.
View Article and Find Full Text PDFJ Hazard Mater
January 2025
State Key Laboratory of Advanced Environmental Technology, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China; Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control and Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou 510640, China.
The effects of micro- and nano-plastics (MNPs) on human health are of global concern because MNPs are ubiquitous, persistent, and potentially toxic, particularly when bound to atmospheric fine particles (PM). Traditional quantitative analysis of MNPs by pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS) is often inaccurate because of false positive signals caused by similar polymers and organic compounds. In this study, a reliable analytical strategy combining HNO digestion and chromatographic peak reconstruction was developed to improve the precision of pyrolysis-gas chromatography-mass spectrometry analysis of multiple MNPs bound to PM.
View Article and Find Full Text PDFJ Hazard Mater
January 2025
Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China.
Microplastics (MPs) and perfluorobutanoic acid (PFBA), emerging contaminants, are ubiquitous in the environment and toxic to organisms. The interaction of MPs with other contaminants can affect their toxicity. However, the impact of MPs on PFBA toxicity remains unknown.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!