Polyamorphism and frustrated crystallization in the acid-base reaction of magnesium potassium phosphate cements

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68378297%3A_____%2F18%3A00491029" target="_blank" >RIV/68378297:_____/18:00491029 - isvavai.cz</a>

Result on the web

<a href="http://dx.doi.org/10.1039/C8CE00670A" target="_blank" >http://dx.doi.org/10.1039/C8CE00670A</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1039/c8ce00670a" target="_blank" >10.1039/c8ce00670a</a>

Result language

angličtina

Original language name

Polyamorphism and frustrated crystallization in the acid-base reaction of magnesium potassium phosphate cements

Original language description

Magnesium potassium phosphate cements are a class of acid−base cements for bioengineering and civil engineering applications. The kinetics of the chemical reaction was investigated in-situ with isothermal conduction calorimetry and with powder X-ray diffraction, quantifying amorphous and crystalline products. The first reaction step, dissolution of MgO, with apparent activation energy of 71 kJ/mol, dictates the time-evolution of two amorphous intermediate precursors and of the crystalline product. The early crystallization of the latter has been described with an Avrami equation with apparent activation energy of 81 kJ/mol, pointing to a mechanism of deceleratory nucleation and growth in one direction, compatible with the acicular crystal habit observed with electron microscopy. The observed polyamorph transformation is controlled by a complex interplay between kinetic and thermodynamic factors, in which the changes in chemical environment (increase in pH) driven by the MgO dissolution, play a crucial role. It is proposed that the onset of the amorphous-amorphous transformation hinders crystallization by decreasing ion mobility, raising the energy barriers to structural reorganization. The rate of MgO dissolution depends on the reactivity of the powder and parameters of the mix (such as the amount of liquid) and influences the reaction pathways, impacting on material performance.

Czech name

—

Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10403 - Physical chemistry

Project

<a href="/en/project/LO1219" target="_blank" >LO1219: Sustainable advanced development of CET</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2018

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

CrystEngComm

ISSN

1466-8033

e-ISSN

—

Volume of the periodical

20

Issue of the periodical within the volume

32

Country of publishing house

GB - UNITED KINGDOM

Number of pages

13

Pages from-to

4600-4613

UT code for WoS article

000442612000011

EID of the result in the Scopus database

2-s2.0-85051475594