A STUDY OF THE POROSITY OF WATER-PLASTICIZED POLYACRYLONITRILE FILMS BY THERMAL-ANALYSIS AND MICROSCOPY

Authors
Citation
Dm. Price et Z. Bashir, A STUDY OF THE POROSITY OF WATER-PLASTICIZED POLYACRYLONITRILE FILMS BY THERMAL-ANALYSIS AND MICROSCOPY, Thermochimica acta, 249, 1995, pp. 351-366
Citations number
33
Categorie Soggetti
Chemistry Analytical
Journal title
ISSN journal
00406031
Volume
249
Year of publication
1995
Pages
351 - 366
Database
ISI
SICI code
0040-6031(1995)249:<351:ASOTPO>2.0.ZU;2-S
Abstract
In a previous study, the morphology of water-plasticised polyacrylonit rile (PAN) film, made by compression moulding moist polymer powder, wa s discussed. The X-ray diffraction pattern of the plasticised film was different from that of dry PAN and this led to the suggestion that hy drated polymer crystallites had been formed by a portion of the water. The location of the remainder of the water was unknown. In this work, the thermal behaviour of the water-plasticised PAN at sub-ambient tem peratures has been examined. When the film was cooled below room tempe rature, two distinct exothermic peaks were observed at -17 degrees C a nd -38 degrees C due to the formation of ice. By analysing the data in terms of thermoporometry, which has been more widely used to study th e freezing of condensates in porous ceramic materials, it was conclude d that the water-plasticised films had a micro-porous morphology. The DSC results suggested a bimodal distribution of pore sizes, but scanni ng electron microscopy revealed a third category of pores with larger size. These large pores were not detected by calorimetry because they were not fully filled with water.