Reactions of poly(vinylidene fluoride)[PVDF], poly(vinylidene fluoride-co-hexafluoropropylene) [poly(VDF-co-HFP)] copolymer, and poly(vinylidene fluoride-co-perfluoromethyl vinyl ether) [poly(VDF-co-PMVE)] copolymer in subcritical water were performed with the aim to develop a technique for recycling fluorine element. By addition of KMnO 4 to the system, quasi-complete mineralization of PVDF was achieved at a rather low temperature (250 °C). When PVDF was reacted for 18 h in the presence of KMnO 4 (158 mM, corresponding to a 1.6-fold molar excess relative to both fluorine and carbon atom contents of PVDF), the fluoride ions (F − ) yield reached 100%, and the amount of remaining total organic carbon decreased to 2% of the carbon atoms in the initial PVDF. Poly(VDF-co-HFP) and poly(VDF-co-HFP) copolymers also showed quasi-complete mineralizations under the same conditions. During the reactions, MnO 4 − was modified into MnO 2 . Compared to the previous method using H 2 O 2 , the reaction temperature that allows a complete mineralization was reduced by 50 °C.

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-The main objective of the present work is to analyze the influence of some important operational reaction parameters (agitation speed, polybutadiene -PB -content and initiator concentration) on the final properties of High Impact Polystyrene (HIPS) produced in bulk. Variable effects are analyzed both qualitatively and quantitatively with the help of a fractional factorial design. Physical, chemical and mechanical properties were evaluated through measurement of the weight-average molecular weight (M w ), polydispersity (PD), volume-average diameter of PB particles (D(4,3)) and impact strength (Izod). It was found that PD and D(4,3) depend strongly on the initiator concentration, rubber concentration and agitation speed; Mw depends on initiator and rubber concentrations; and Izod depends on the rubber concentration, PD and D(4,3) in the analyzed experimental range. As a consequence, it was shown that control of final polymer properties can be easily performed through proper manipulation of the analyzed operational variables.

Summary: Polystyrene/cornstarch blends were prepared by melt‐processing in the presence of maleic anhydride (MA), using an internal mixer as reactor. Scanning electron microscopy (SEM) was used to visualize the blends morphology. Addition of MA contributed to improve interfacial adhesion between the two phases. Soil burial tests were used to investigate biodegradability. Results from samples weight loss, as a function of incubation time, revealed that the increase in the content of starch contributed to increase biodegradability. The results showed that the microbial activity inside the specimens was accelerated in the first 15 days of evaluation. Photographs of the films showed significant differences after 30 days of incubation in soil. SEM was also used to evaluate biodegradation, and revealed fractured surfaces covered with a heterogeneous microorganism community.