Pore blockage effect of NOM on atrazine adsorption kinetics of PAC: the roles of PAC pore size distribution and NOM molecular weight

2003 ◽  
Vol 37 (20) ◽  
pp. 4863-4872 ◽  
Author(s):  
Q Li
Keyword(s):  
Molecular Weight ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Adsorption Kinetics ◽  
Pore Blockage ◽  
Kinetics Of ◽  
Blockage Effect

Macroporous Thermosets via Chemically Induced Phase Separation

1996 ◽  
Vol 431 ◽  
Author(s):  
J. Kiefer ◽  
R. Porouchani ◽  
D. Mendels ◽  
J. B. Ferrer ◽  
C. Fond ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Phase Separation ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
New Technology ◽  
Curing Temperature ◽  
Low Molecular Weight ◽  
Closed Cell ◽  
Chemically Induced

AbstractWe have explored a new technology based on chemically induced phase separation that yields porous epoxies and cyanurates with a closed cell morphology and micrometer sized pores with a narrow pore size distribution. When the precursor monomers are cured in the presence of a low molecular weight liquid, the desired morphology results from a phase separation and a chemical quench. After phase separation, the porosity is achieved by thermal removal of the secondary liquid phase, specifically by diffusion through the crosslinked matrix. In respect to the thermodynamics and kinetics, the origin of the phase separation process can be identified as nucleation and growth. The influence of internal and external reaction parameters, such as chemical nature of the low molecular weight liquid, its concentration and the curing temperature on the final morphology are presented. Thus, the morphology can be controlled ranging from a monomodal to bimodal pore size distribution with pore sizes inbetween 1 to 10 μm. These porous thermosets are characterized by a significantly lower density, without any loss in thermal stability compared to the neat matrix. Such new materials demonstrate great interest for lowering the dielectric constant and for improving the fundamental understanding of the role of voids in stress relaxation and toughening.

scholarly journals How Molecular Weight Cut-Offs and Physicochemical Properties of Polyether Sulfone Membranes Affect Peptide Migration and Selectivity during Electrodialysis with Filtration Membranes

Membranes ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 153 ◽  
Author(s):  
Sabita Kadel ◽  
Geneviève Pellerin ◽  
Jacinthe Thibodeau ◽  
Véronique Perreault ◽  
Carole Lainé ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Physicochemical Properties ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Negative Charge ◽  
Protein Hydrolysate ◽  
Filtration Membranes ◽  
Polyether Sulfone ◽  
Wide Range

Filtration membranes (FMs) are an integral part of electrodialysis with filtration membranes (EDFM), a green and promising technology for bioactive peptide fractionation. Therefore, it is paramount to understand how physicochemical properties of FMs impact global and selective peptide migration to anionic (A−RC) and cationic (C+RC) peptide recovery compartments during their simultaneous separation by EDFM. In this context, six polyether sulfone (PES) membranes with molecular weight cut-offs (MWCO) of 5, 10, 20, 50, 100 and 300 kDa were characterized and used during EDFM to separate peptides from a complex whey protein hydrolysate. Surface charge, roughness, thickness and surface/pores nature of studied PES membranes were similar with small differences in conductivity, porosity and pore size distribution. Interestingly, global peptides migration to both recovery compartments increased linearly as a function of MWCO. However, peptide selectivity changed according to the recovery compartments and/or the peptide’s charge and MW with an increase in MWCO of FMs. Indeed, in A−RC, the relative abundance (RA) of peptides having low negative charge and MW (IDALNENK and VLVLDTDYK) decreased (45% to 19%) with an increase in MWCO, while the opposite for peptides having high negative charge and MW (TPEVDDEALEK, TPEVDDEALEKFDK & VYVEELKPTPEGDLEILLQK) (increased from 16% to 43%). Concurrently, in C+RC, regardless of MWCO used, the highest RA was observed for peptides having low positive charge and MW (IPAVFK & ALPMHIR). It was the first time that the significant impact of charge, MWCO and pore size distribution of PES membranes on a wide range of MWCO was demonstrated on EDFM performances.

Fabrication of ultrahigh-molecular-weight polyethylene porous implant for bone application

2020 ◽  
Vol 40 (8) ◽  
pp. 685-692
Author(s):  
Beatriz Olalde ◽  
Ana Ayerdi-Izquierdo ◽  
Rubén Fernández ◽  
Nerea García-Urkia ◽  
Garbiñe Atorrasagasti ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Structural Integrity ◽  
Fibre Diameter ◽  
Pore Wall ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Salt Leaching ◽  
Ultrahigh Molecular Weight

AbstractPorous implants play a crucial role in allowing ingrowth of host connective tissue and thereby help in keeping the implant in its place. With the aim of mimicking the microstructure of natural extracellular matrix, ultrahigh-molecular-weight polyethylene (UHMWPE) porous samples with a desirable pore size distribution were developed by combining thermally induced phase separation and salt leaching techniques. The porous UHMWPE samples consisted of a nanofibrous UHMWPE matrix with a fibre diameter smaller than 500 nm, highly interconnected, with a controllable pore diameter from nanoscale to 300 µm. Moreover, a porous UHMWPE sample was also developed as a continuous and homogeneous coating onto the UHMWPE dense sample. The dense/porous UHMWPE sample supported human foetal osteoblast 1.19 cell line proliferation and differentiation, indicating the potential of porous UHMWPE with a desirable pore size distribution for bone application. An osseointegration model in the sheep revealed substantial bone formation within the pore layer at 12 weeks via SEM evaluation. Ingrown bone was more closely opposed to the pore wall when compared to the dense UHMWPE control. These results indicate that dense/porous UHMWPE could provide improved osseointegration while maintaining the structural integrity necessary for load-bearing orthopaedic application.

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