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H. Jasińska, H. Głowala, L. Łukasik, J. Brzeziński



GPC studies of the ageing process of phenol-formaldehyde resols (in English)


Polimery 1993, No 1, 20


DOI: dx.doi.org/10.14314/polimery.1993.020

Summary

GPC method was used for the determination of changes in average molecular weights (MW) and molecular weight distribution (MWD) of liquid resolic phenol-formaldehyde resins during their storage at 40, 20 or 4°C till the appearance of THF-insoluble fractions. The effect of molar ratio of reagents (Fo/Ph = 2.5 or 1.6), temperature of resin condensation (70°C or boiling tem perature) and degree of condensation (water tolerance of resin equal to 1 or 20 ml) was studied. Storage life of the resins at 40°C was -2 weeks, at 20°C -3 months, and at 4°C more than 3 years. More stable were resins prepared at lower Fo/Ph molar ratio and at higher temperature. In resins prepared at higher Fo I Ph molar ratio changes during storage at all storage temperatures took place both in the range of low-MW and high-MW fractions, whereas resins prepared at lower Fo/Ph molar ratio condense during storage mainly in the range of high MW.


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