Synthesis, Cement Paste Fluidities and Molecular Weight Measurements of Polycarboxylate Superplasticizer by Bulk Polymerization

2013 ◽  
Vol 405-408 ◽  
pp. 2778-2781
Author(s):  
Xiao Liu ◽  
Zi Ming Wang ◽  
Xu Liang ◽  
Jie Zhu ◽  
Jue Zhao
Keyword(s):  
Molecular Weight ◽  
Polyethylene Glycol ◽  
Solid State ◽  
Maleic Anhydride ◽  
Cement Paste ◽  
Fumaric Acid ◽  
Bulk Polymerization ◽  
Synthesis Process ◽  
The Third ◽  
Polycarboxylate Superplasticizer

The synthesis process of polycarboxylate superplasticizer (PCE) by bulk polymerization was investigated. Compared with BPO as initiator, PCE prepared by using AIBN as initiator exhibited better cement paste fluidities. PCE using isopentenyl polyethylene glycol (TPEG) or isobutenyl polyethylene glycol (IPEG) as macromonomer showed excellent fluidities and retaining properties at 80°C and 75°C, respectively. The fumaric acid was more suitable to copolymerize as the third monomer than maleic anhydride. The molecular weight measurements showed that the characteristics of molecular weight and its distribution for all the synthesized samples were in accordance with their cement paste fluidities. The solid-state PCEs can be conveniently dissolved into water to prepare PCE solution with arbitrary concentration, and still with good cement application performances.

scholarly journals Absorption of sugars by the piglet

1968 ◽  
Vol 22 (3) ◽  
pp. 501-514 ◽  
Author(s):  
D. E. Kidder ◽  
M. J. Manners ◽  
M. R. McCrea ◽  
A. D. Osborne
Keyword(s):  
Molecular Weight ◽  
Small Intestine ◽  
Polyethylene Glycol ◽  
High Molecular Weight ◽  
Alimentary Tract ◽  
The Third ◽  
Sugar Mixtures

1. Diets containing various sugar mixtures together with polyethylene glycol of high molecular weight as a marker were fed to pigs 1, 2 and 3 weeks old. The piglets were slaughtered 2.5 h later, and the ratio of sugar to marker was determined in the contents of the alimentary tract as far as the caecum.2. The greatest fall was found in the first part of the small intestine.3. Glucose had always disappeared by the third quarter of the small intestine.4. Xylose and fructose disappeared more slowly, especially in the younger pigs, but were usually absent from the contents of the last quarter of the small intestine.5. Sucrose was removed far less completely, and the ratio of sucrose to marker frequently did not decrease along the second half of the small intestine. Sucrose was removed much less efficiently when it formed 15% of the diet than when it formed only 5%, and much less efficiently by the younger than by the older pigs.

scholarly journals Study on adsorption, rheology and hydration behaviours of Polycarboxylate(PCE) superplasticizer synthesized by different acid to ether ratio

2021 ◽  
Vol 2133 (1) ◽  
pp. 012007
Author(s):  
Zhijun Lin ◽  
Xiaofang Zhang ◽  
Zhanhua Chen ◽  
Yue Xiao ◽  
Yunhui Fang
Keyword(s):  
Molecular Weight ◽  
Adsorption Capacity ◽  
Cement Paste ◽  
Cement Hydration ◽  
Main Chain ◽  
Chain Structure ◽  
Hydration Process ◽  
Side Chain ◽  
Structure Parameters ◽  
Polycarboxylate Superplasticizer

Abstract Polycarboxylate superplasticizer is synthesised by different acid to ether ratio, which is changing the main chain structure parameters, obtained different microstructures. The effect of different microstructure PCE superplasticizer on the fluidity of cement paste, rheological thixotropy, adsorption capacity and hydration heat are studied. The results show that dispersing performance in cement with acid to ether ratio of 3.5 is the best, the molecular weight and side chain density have rather little effect on the cement hydration process.

scholarly journals Does Primed Seed Improve Stand Establishment and Yield of Broccoli?

1995 ◽  
Vol 5 (4) ◽  
pp. 314-317 ◽  
Author(s):  
Lewis W. Jett ◽  
Gregory E. Welbaum ◽  
Charles R. O'Dell ◽  
Ronald D. Morse
Keyword(s):  
Molecular Weight ◽  
Polyethylene Glycol ◽  
Brassica Oleracea ◽  
Seedling Emergence ◽  
Plant Competition ◽  
Seed Priming ◽  
Stand Establishment ◽  
The Third ◽  
The Mean ◽  
Mean Time

The effect of matric and osmotic seed priming on stand establishment and maturity of broccoli (Brassica oleracea L. var. italica) was investigated in three years at two locations in Virginia. Seeds (`Earlidawn') were primed at 1.1 MPa (68F for 7 days) either osmotically in polyethylene glycol (8000 molecular weight) or metrically in vermiculite (horticultural grade no. 2). In the frost year of the study, seeds were hand-seeded in August into crustprone soil with a mean temperature of 82F, and there were no differences in the percentage or mean time of seedling emergence between osmotic- and matric-primed seeds. Under cooler temperatures during the remaining two years of the study, priming increased the percent emergence and decreased the mean time of emergence by about 15 hours. Primed seeds did not increase yields or accelerate maturity in two out of three years. In the third year, the spread of seedling emergence times was less for primed seeds, which reduced plant-to-plant competition and hastened maturity. The primary benefit of primed broccoli seeds was faster emergence, which increased stands by reducing exposure to stresses that decrease emergence.

Preparation and Properties of New Polycarboxylate-Type Superplasticizer

2011 ◽  
Vol 194-196 ◽  
pp. 1122-1125
Author(s):  
Sheng Hua Lv ◽  
Rui Jun Gao ◽  
Jian Ping Duan ◽  
Xiao Liang Yan ◽  
Ming Ming Hou
Keyword(s):  
Molecular Weight ◽  
Polyethylene Glycol ◽  
Maleic Anhydride ◽  
Sulfonic Acid ◽  
Setting Time ◽  
Monomethyl Ether ◽  
Ammonium Persulfate ◽  
Molar Ratio ◽  
Glycol Monomethyl Ether ◽  
Relative Molecular Weight

A modified polycarboxylate superplasticizer was synthesized by copolymerization of polyethylene glycol monomethyl ether methacrylate (MPEG-MA), β–Cyclodextrins grafted maleic anhydride (MAH-β-CD), methacrylic acid (MAA) and methallyl sulfonic acid (MAS). The excellent superplasticizer was obtained at the molar ratio of n(MAH-β-CD) : n(MAS) : n(MAA) : n(MPEG-MA) was 0.05:0.1:3:1 using ammonium persulfate (APS) as initiator at 90°C for 5 h. The applied results show that the product had many advantages, such as lower dosage, longer setting time, better flow-keeping ability and better compatibility with different cement. Meanwhile, the structure and relative molecular weight were characterized by FTIR and GPC respectively.

scholarly journals The influence of the structural parameters of polycarboxylate superplasticizer on the dispersion and adsorption

2021 ◽  
Vol 2133 (1) ◽  
pp. 012011
Author(s):  
Shaohong Zhu ◽  
Yanmei Lin ◽  
Yunhui Fang ◽  
Yuliang Ke ◽  
Huazhen Lai ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Conversion Rate ◽  
Molecular Design ◽  
Raw Materials ◽  
Structural Parameters ◽  
Average Molecular Weight ◽  
Synthesis Process ◽  
Side Chain ◽  
Weight Average Molecular Weight ◽  
Polycarboxylate Superplasticizer

Abstract Polycarboxylate superplasticizers with different structural parameters were synthesized by isobutylene polyoxyethylene ether, acrylic acid and ammonium persulfate as raw materials from the perspective of molecular design. The influence of polycarboxylate superplasticizer on cement adsorption was characterized by cement adsorption capacity test and fluidity test, etc. At the same time, the adsorption change of polycarboxylate superplasticizer on the surface of cement particles was also revealed. It was found that the best adsorption and dispersion properties on cement paste were obtained under the heating synthesis process when the structure of the water reducing agent was designed to have a weight average molecular weight of 55128, a macromonomer conversion rate of 84.61%, and a side chain density of 0.1725. For the normal temperature process, when the weight average molecular weight was 103920, the macromonomer conversion rate 92.03%, and the side chain density 0.3115, the best effects in cement can be achieved.

The Collagenic Molecular Structural Unit of Solid State Complexes

1971 ◽  
Vol 29 ◽  
pp. 478-479
Author(s):  
Kenneth M. Richter ◽  
John A. Schilling
Keyword(s):  
Molecular Weight ◽  
Solid State ◽  
Structural Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Naoh Treatment

The structural unit of solid state collagen complexes has been reported by Porter and Vanamee via EM and by Cowan, North and Randall via x-ray diffraction to be an ellipsoidal unit of 210-270 A. length by 50-100 A. diameter. It subsequently was independently demonstrated by us in dog tendon, dermis, and induced complexes. Its detailed morphologic, dimensional and molecular weight (MW) aspects have now been determined. It is pear-shaped in long profile with m diameters of 57 and 108 A. and m length of 263 A. (Fig. 1, tendon, KMnO4 fixation, Na-tungstate; Fig. 2a, schematic of unit in long, C, and x-sectional profiles of its thin, xB, and bulbous, xA portions; Fig. 2b, tendon essentially unmodified by ether and 0.4 N NaOH treatment, Na-tungstate). The unit consists of a uniquely coild cable, c, of ṁ 22.9 A. diameter and length of 2580-3316 A. The cable consists of three 2nd-strands, s, each of m 10.6 A.

Sign in / Sign up

Export Citation Format

Share Document