scholarly journals Influence of Monomer Ratios on Molecular Weight Properties and Dispersing Effectiveness in Polycarboxylate Superplasticizers

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 1022 ◽  
Author(s):  
Huiqun Li ◽  
Yan Yao ◽  
Ziming Wang ◽  
Suping Cui ◽  
Yali Wang
Keyword(s):  
Molecular Weight ◽  
Polyethylene Glycol ◽  
Acrylic Acid ◽  
Reaction Rate ◽  
Main Chain ◽  
Size Exclusion ◽  
Side Chain ◽  
Time Interval ◽  
Exclusion Chromatography ◽  
Low Dosage

A series of polycarboxylate superplasticizer (PCE) polymers were synthesized from acrylic acid (AA) and isoprenyloxy polyethylene glycol ether (IPEG) at the mole ratios of 3.0, 4.2, 5.0 and 6.0. In this study, the molecular weight properties of PCE polymers were recorded by size exclusion chromatography with the time interval of 1 h. Mini slump test was used to detect the dispersing effectiveness of PCE polymer in cement paste. The results indicated that the reaction rate of monomers, conversion of 52IPEG macromonomer and molecular weight of PCE polymers increased with the general adding ratio of AA to IPEG macromonomers while the side chain density of PCE polymers decreased. PCE polymers possessed molecular weight around 30,000 g/mol with low side chain density, and long main chain length presented high initial dispersing effectiveness at the low dosage around 0.12%. The majority of effective PCE polymers were formed during the adding period of acrylic acid in the first 3 h.

Polymerization of Nitrophenyl and 3-Diethylaminophenyl Prop-2-yn-1-yl Ethers with PdCl2. Polymers and Copolymers Characterization

1998 ◽  
Vol 63 (11) ◽  
pp. 1803-1814 ◽  
Author(s):  
Hynek Balcar ◽  
Petr Holler ◽  
Jan Sedláček ◽  
Vratislav Blechta
Keyword(s):  
Molecular Weight ◽  
Dimethyl Sulfoxide ◽  
Size Exclusion Chromatography ◽  
Main Chain ◽  
Size Exclusion ◽  
Low Molecular Weight ◽  
Molecular Weight Distributions ◽  
Weight Distributions ◽  
Exclusion Chromatography

2-, 3- and 4-Nitrophenyl prop-2-yn-1-yl ethers were polymerized with PdCl2 in N,N-dimethylformamide (DMF) giving brown polymers soluble in DMF, dimethyl sulfoxide and N-methylpyrrolidone. Broad (mostly bimodal) molecular weight distributions were observed by size-exclusion chromatography (SEC) with maxima at molecular weight of about 4 . 103 and 1 . 105. With the same catalyst, 3-diethylaminophenyl prop-2-yn-1-yl ether gave predominantly low molecular weight homopolymer (Mn = 4 200) soluble in DMF, N-methylpyrrolidone, CHCl3 and tetrahydrofuran-soluble copolymers with 4-nitrophenyl prop-2-yn-1-yl ether (Mn about 3 000). IR, NMR and UV-VIS spectra of prepared polymers and copolymers proved the structure to consist of the polyene-type main chain with phenoxymethyl pendant groups bearing nitro or diethylamino substituents.

scholarly journals Existence of a squamous cell carcinoma antigen-immunoglobulin complex causes a deviation between squamous cell carcinoma antigen concentrations determined using two different immunoassays: first report of squamous cell carcinoma antigen coupling with immunoglobulin A

2017 ◽  
Vol 54 (6) ◽  
pp. 655-663
Author(s):  
Eriko Mori ◽  
Makoto Kurano ◽  
Akiko Tobita ◽  
Hironori Shimosaka ◽  
Yutaka Yatomi
Keyword(s):  
Molecular Weight ◽  
Squamous Cell Carcinoma ◽  
Polyethylene Glycol ◽  
Cell Carcinoma ◽  
Size Exclusion Chromatography ◽  
Squamous Cell ◽  
Size Exclusion ◽  
Squamous Cell Carcinoma Antigen ◽  
Large Molecular Weight ◽  
Exclusion Chromatography

Background Squamous cell carcinoma antigen is used as a tumour marker and is routinely measured in clinical laboratories. We validated two different immunoassays and found three cases in which the squamous cell carcinoma antigen concentrations deviated greatly between the two immunoassays. Here, we aimed to elucidate the mechanisms responsible for these deviations. Methods The squamous cell carcinoma antigen concentrations were determined using the ARCHITECT SCC (CLIA method) and the ST AIA-PACK SCC (FEIA method). We performed polyethylene glycol precipitation and size exclusion chromatography to assess the molecular weight and spike recovery and absorption tests to examine the presence of an autoantibody. Results Both methods exhibited good performances for the measurement of squamous cell carcinoma antigen, although a correlation test showed large differences in the squamous cell carcinoma antigen concentrations measured using the two methods in three cases. The results of polyethylene glycol treatment and size exclusion chromatography indicated the existence of a large molecular weight squamous cell carcinoma antigen in these three cases. The spike recovery tests suggested the possible presence of an autoantibody against squamous cell carcinoma antigen. Moreover, the absorption test revealed that large squamous cell carcinoma antigen complexes were formed by the association of squamous cell carcinoma antigen with IgG in two cases and with both IgG and IgA in one case. Conclusions This study describes the existence of large molecular weight squamous cell carcinoma antigen that has complexed with immunoglobulin in the serum samples. The reason for the deviations between the two immunoassays might be due to differences of their reactivities against the squamous cell carcinoma antigen immune complexes with their autoantibody. To our knowledge, this is the first report to describe the coupling of squamous cell carcinoma antigen with IgA.

Autoxidative Degradation of Poly(phenylacetylene)

1993 ◽  
Vol 58 (11) ◽  
pp. 2651-2662 ◽  
Author(s):  
Jiří Vohlídal ◽  
Dana Rédrová ◽  
Marta Pacovská ◽  
Jan Sedláček
Keyword(s):  
Molecular Weight ◽  
Solid State ◽  
Induction Period ◽  
High Molecular Weight ◽  
Size Exclusion Chromatography ◽  
Main Chain ◽  
Size Exclusion ◽  
Cross Linking ◽  
Exclusion Chromatography ◽  
High Molecular Weight Poly

Autooxidative degradation of high molecular-weight poly(phenylacetylene) (PPhA) in solid state and in solution was studied using the size exclusion chromatography (SEC) and UV, IR, and EPR spectrometry. No degradation was observed on PPhA stored in vacuum, whereas the polymer exposed to air was found to degrade without any induction period. No evidence of a cross-linking of oxidized PPhA was observed. The degradation of PPhA was found to be: (i) practically non-influenced by an ambient, diffuse day-light; (ii) of the random type (i.e. each main-chain bond of PPhA has the same probability of being ruptured); and (iii) fast enough to influence the results of SEC measurements.

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