Thermoplastic Multicomponent Blends Demixing by High-Pressure-High Temperature solvent extractions

MARTINI, RAQUEL EVANGELINA; DÍAZ, MÓNICA FÁTIMA; MABE, GUILLERMO; BRIGNOLE, ESTEBAN ALBERTO; CAPIATI, NUMA JOSÉ; BARBOSA, SILVIA ELENA

Ischia, Italia

Conferencia; II International Conference on Times of Polymers (TOP); 2004

Unive4rsidad de Nápoles, Italia

Polymer blends are very important commercial materials that permit to obtain new materials with improved final properties. This improvement is a function of the phase compatibility, but the principal commercial blends are generated from immiscible polymers. Then, the step of compatibilization is fundamental. Within the methods for doing this, the most efficient is the reactive compatibilization.. It is obtained by the in-situ generation of a copolymer, which enhances the dispersed phase morphology parameters (particle size, size distribution, and interparticle distance), and interface adhesion. The characterization of this copolymer depends on the possibility of its neat separation from the raw copolymers involved in the blend. When the raw materials are high molecular weight commercial ones, this separation is very difficult by traditional selective solvent extractions (like soxhlet at atmospheric pressure). The use of high-pressure high temperature solvent extraction is an interesting alternative to obtain the total separation. Because permits a drastic changes in polymer/copolymer solubilization trough changes in parameters like pressure, temperature, etc. In this work, a polymer blend components separation using high-pressure fluids is proposed. Results from PE/PS/PE-g-PS blend demixing with propane, pentane and n-heptane at 140C and 300 atm are present. PE-g-PS was in-situ generated by a low cost Friedel-Crafts reaction in melt form. Sharp separation was obtained and the relative influence of solvent length, temperature and pressure were analyzed.