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On the stereomicrostructure‐based mechanisms of physical properties of poly(methyl methacrylate): 1. space charge behaviour and physical ageing
Author(s) -
Guarrotxeekane,
de Frutos Manuel
Publication year - 2007
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.2178
Subject(s) - tacticity , differential scanning calorimetry , methyl methacrylate , tetrad , microstructure , enthalpy , materials science , space charge , methacrylate , poly(methyl methacrylate) , polymer chemistry , analytical chemistry (journal) , chemistry , thermodynamics , polymer , composite material , copolymer , organic chemistry , physics , electron , mathematical physics , quantum mechanics , polymerization
Three samples of poly(methyl methacrylate) (PMMA) were characterized after careful purification. Their composition in terms of some repeating stereosequences, especially mmr termini of isotactic sequences, was determined. Their space charge behaviour was analysed using the thermal step (TS) method. A correlation between the electrical current intensity, as given by the TS method, and the stereochemical microstructure content in each sample was evidenced. The results are explained in the light of previous data on the specific microstructures present in the samples at different contents. The physical ageing of the samples was studied, quantitatively, through differential scanning calorimetry measurements prior to and after equally performed thermal treatments of the samples. The corresponding values of the loss of enthalpy agree with the content of mmr tetrad termini of isotactic sequences. The results are analysed on the basis of the differences in stereochemical composition of the samples. The results give further evidence of the role of some definite stereosequences in physical properties as proposed in earlier works on poly(vinyl chloride) and polypropylene. Copyright © 2006 Society of Chemical Industry