نتایج جستجو برای: average molecular weight

تعداد نتایج: 1269208  

Journal: :Sains Malaysiana 2021

Polyvinyl benzyl chloride (PVBC) was synthesized by free radical polymerization of 4-vinylbenzyl using benzoyl peroxide initiator at 60 °C. PVBC synthesised in different solvents such as toluene, xylene, 1,4-dioxane, and tetrahydrofuran. The polymers were structurally characterized 1H NMR FTIR spectroscopic techniques. thermal property the polymer investigated thermogravimetric analysis (TGA) d...

2017
Author Terao Ken Terao Jimmy W. Mays

On-line two-angle (15 and 90) light scattering measurements with a gel permeation chromatograph for linear and branched polystyrene in tetrahydrofuran (a good solvent) and in trans-decalin (a theta solvent) were made and compared with data from a multi-angle light scattering detector and literature values. Theoretically, weight-average molecular weight and the radius of gyration Rg can be det...

2014
James S. Fabiyi Armando G. McDonald

Effects of accelerated and natural weathering on the molecular weight distribution (MWD) and crystallinity of polypropylene (PP) in wood plastic composites (WPC) were investigated. The composites were produced from pine fibers (60%) and PP (40%). Prolonged weathering caused an increase in wood degradation and erosion thereby leaving cracks and ‘‘pits’’ on the surface. Pyrolysis gas chromatograp...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1975
W R Fisher M G Hammond M C Mengel G L Warmke

The molecular weight of monodisperse human plasma low densitylipoprotein has been measured in 69 individuals and found to vary over the range of 2.4 to 3.9 X 10-6. By contrast, the molecular weight of low density lipoprotein measured on two separate occasions for specific individuals shows a mean difference of 0.07 X 10-6 and a standard deviation of 0.08 X 10-6; hence low density lipoprotein di...

Journal: :Applied and environmental microbiology 1994
K M Kleman-Leyer T K Kirk

Three extracellular cellulose-depolymerizing enzymes from cotton undergoing decay by the brown rot fungus Meruliporia (Serpula) incrassata were isolated by anion-exchange and hydrophobic interaction chromatographies. Depolymerization was detected by analyzing the changes in the molecular size distribution of cotton cellulose by high-performance size-exclusion chromatography. The average degree ...

Journal: :Molecules 2015
Josua Timotheus Oberlerchner Thomas Rosenau Antje Potthast

The purpose of this article is to provide the reader with an overview of the methods used to determine the molecular weights of cellulose. Methods that employ direct dissolution of the cellulose polymer are described; hence methods for investigating the molecular weight of cellulose in derivatized states, such as ethers or esters, only form a minor part of this review. Many of the methods descr...

Journal: :Journal of natural products 1997
K Sepcić G Guella I Mancini F Pietra M D Serra G Menestrina K Tubbs P Macek T Turk

From the marine sponge Reniera sarai 3-alkylpyridinium oligomers and polymers have been isolated. 3-Alkylpyridinium polymers are potent anticholinesterase agents; in addition, they show hemolytic and cytotoxic activities. Oligomers with a molecular weight lower than 3000 Da do not possess any significant activity. We report structural characterization of 3-alkylpyridinium polymers and their beh...

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