Influence of hot-melt extrusion and compression molding on polymer structure organization, investigated by differential scanning calorimetry

Article Article scientifique Article Influence of hot-melt extrusion and compression molding on polymer structure organization, investigated by differential scanning calorimetry eng 2001 author Sarraf A.G. author Tissot Henri 25813 author Tissot Paul 25052 author Alfonso Dorothée Vera 24124 author Gurny Robert 24779 author Doelker Eric 25151 3124-3132 10.1002/app.1764 1097-4628 http://doi.wiley.com/10.1002/app.1764 A blend of a pullulan polymer and 1,2,6‐hexanetriol as a plasticizer were used to study the effect of melt processing techniques on the physical properties of the resulting materials. The main advantage of pullulan is its linear polysaccharide chain model structure. Hot‐melt extrusion and compression molding were performed under the same temperature and pressure conditions. The materials obtained were analysed by differential scanning calorimetry. For the first time, the comparative effect of the two processing techniques, i.e., extrusion and compression molding, on the polymer arrangement is reported. Endothermic events resulted from the melt extrusion process were shown to be related to different structures of oriented populations of macromolecules and to microphase separation. Orientation was enhanced by cooling the extrudate at the die exit, with a corresponding increased enthalpy from 34.7 to 51.4 J/g. In contrast, when using compression molding, the endotherm was less marked (11.9 J/g), suggesting less orientation, but the shape of the thermogram was quite similar to that of the extrudate. In both cases, we observed a loss of orientation when the molded materials were milled. A semiquantitative kinetic study of the disorientation process of the extrudate upon isothermic tempering suggests that a disorientation phenomenon occurs at the same time as a swelling process due to the presence of microphase separation. The extrudate was shown to be stable at 25°C. Dewey 540 40 Département de chimie minérale, analytique et appliquée 145 false Journal of Applied Polymer Science 81 13 d2f09738-fe12-4938-8175-cf98c6b6470f Article (Published version) Restricted Sarraf_et_al-2001-Journal_of_Applied_Polymer_Science.pdf 201421 application/pdf restrictedAccess Faculté des sciences / Section de chimie et biochimie / Département de chimie minérale, analytique et appliquée

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Influence of hot-melt extrusion and compression molding on polymer structure organization, investigated by differential scanning calorimetry	Journal of Applied Polymer Science			2001	358	0

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Tissot, Henri