The cement hydration delay is due to comb-polymers (PCP), used as dispersant agent during the preparation of the cement paste. In order to evaluate the role of the PCP structure on hydration, the comb-polymer is separ...The cement hydration delay is due to comb-polymers (PCP), used as dispersant agent during the preparation of the cement paste. In order to evaluate the role of the PCP structure on hydration, the comb-polymer is separated in two main parts: the backbone (PAA) and the dispersing chain. A linear polymer made up of PEO, Mw = 1000, with a carboxylic head suitable to link the inorganic surface, was synthesized to simulate the effect of the dispersing-side chain. The hydration delay of C-S-H formation induced by comb-polymer on CEM I and C3S phase was analyzed by conduction calorimetry and the morphology of the crystalline structure in growth by SEM, specially studying the relation between structure and hydration time. The results show that the hydration delay is mainly ascribable to the comb-shaped structure as a whole, where PEO chain, as from considerations on energy, might assume conformations able to modify the salt concentration near the cement surface. The different hydration rates are tentatively related to the crystal growth and the surface texture observed by SEM.展开更多
To improve the flow ability of crude oil with high content of aromatic asphaltenes,new comb-type copolymers of poly(maleic anhydride-co-α-olefin-costyrene)(MASCs)with different ratios of maleic anhydride(MA)to styren...To improve the flow ability of crude oil with high content of aromatic asphaltenes,new comb-type copolymers of poly(maleic anhydride-co-α-olefin-costyrene)(MASCs)with different ratios of maleic anhydride(MA)to styrene were designed and synthesized.1H NMR and FTIR spectra were used to characterize the chemical structure of the copolymers.The effect of copolymers on the flow ability of model waxy oil and crude oil were studied by rheological method and polarizing light microscopy.Upon the addition of MASCs,the yield stresses of oils were decreased by 1 to 3 orders of magnitude,and the morphology of paraffin crystals were reduced and changed from plates to needles.展开更多
文摘The cement hydration delay is due to comb-polymers (PCP), used as dispersant agent during the preparation of the cement paste. In order to evaluate the role of the PCP structure on hydration, the comb-polymer is separated in two main parts: the backbone (PAA) and the dispersing chain. A linear polymer made up of PEO, Mw = 1000, with a carboxylic head suitable to link the inorganic surface, was synthesized to simulate the effect of the dispersing-side chain. The hydration delay of C-S-H formation induced by comb-polymer on CEM I and C3S phase was analyzed by conduction calorimetry and the morphology of the crystalline structure in growth by SEM, specially studying the relation between structure and hydration time. The results show that the hydration delay is mainly ascribable to the comb-shaped structure as a whole, where PEO chain, as from considerations on energy, might assume conformations able to modify the salt concentration near the cement surface. The different hydration rates are tentatively related to the crystal growth and the surface texture observed by SEM.
基金Financial support by the Science Foundation for the Excellent Youth Scholars of East China University of Science and Technology is gratefully acknowledged.
文摘To improve the flow ability of crude oil with high content of aromatic asphaltenes,new comb-type copolymers of poly(maleic anhydride-co-α-olefin-costyrene)(MASCs)with different ratios of maleic anhydride(MA)to styrene were designed and synthesized.1H NMR and FTIR spectra were used to characterize the chemical structure of the copolymers.The effect of copolymers on the flow ability of model waxy oil and crude oil were studied by rheological method and polarizing light microscopy.Upon the addition of MASCs,the yield stresses of oils were decreased by 1 to 3 orders of magnitude,and the morphology of paraffin crystals were reduced and changed from plates to needles.
