E. Bilbao

Kinetics of the cationic polymerization of N-vinylcarbazole by trityl salts in nitrobenzene

SummaryThe cationic polymerization of N-vinylcarbazole by trityl salts in nitrobenzene at 20°C has been studied. The kp values are independent of initiator concentration and an average value of 8.9.104M−1s−1 has been obtained which, according to the reaction conditions, has been interpreted in terms of propagation by free ions.

Polymer–polymer complexes of poly(N-isopropylacrylamide) and poly(N,N-diethylacrylamide) with poly(carboxylic acids): a comparative study

In this manuscript, the complexation process between two polyacids, poly(acrylic acid) (PAA) and poly(methacrylic acid) (PMAA), and two different polyacrylamides, poly(N-isopropylacrylamide) (PNiPAm) and poly(N,N-diethylacrylamide) (PNdEAm), in organic solvents, has been studied. The influence of polymer chemical structure and the effect of polymer–solvent interactions on the complex formation in solution have been analyzed. Specific interactions were studied by Fourier transform infrared (FTIR) spectroscopy, and the composition of the obtained complexes was determined by elemental analysis. The calorimetric study of the interpolymer complexes shows a unique glass transition temperature for all systems except for PNdEAm/PMAA system in which phase separation was observed after thermal treatment.

Cationic polymerization of n-vinyl carbazole initiated by trityl salts in nitrobenzene

SummaryThe initiation mechanism in the cationic polymerization of N-vinyl carbazole by trityl salts in nitrobenzene has been investigated. An spectroscopic study of the reaction solutions indicates that the triphenylmethyl cation is not present at the end of the polymerization, the mechanism being not therefore similar to that proposed in CH2Cl2. A mechanism involving hydride ion abstraction is proposed.

Studying the Thermal Degradation of Different Polyacenaphthylenes via Thermogravimetric Analysis Combined With Fourier Transform Infrared Spectroscopy (TGA-FTIR)

In this study, the thermal behavior of polyacenaphthylene (PAcN) and partially modified polyacenaphthylene with Cl, Br, and H2PO3 groups, both under air and nitrogen atmosphere, have been investigated. The influence of the molecular weight, the heating rate, and the introduced substituent have been studied. Thermogravimetric Analysis combined with Fourier Transform Infrared Spectroscopy was used to determine the thermal stabilities and the degradation mechanism. All polyacenaphthylene samples degrade through a depolymerisation process under a nitrogen atmosphere, whereas in air, elimination and thermo-oxidation reactions take place.

Reutilization of thermostable polyester wastes by means of agglomeration with phenolic resins

We report on the possibility of obtaining organic polymeric matrixes allowing the development of new high performance fire-resistant products by recycling downsized thermostable waste materials. Phenolic resins have been used as binders for recycled waste. Furthermore, considering that reinforced plastic triturations have superior properties (chemical, mechanical, water resistance, etc.) to wood agglomerates, significant advantages over conventional materials are anticipated. In summary, we propose a viable solution to some of the known problems caused by the consumption of wood and to the needs of strengthened plastic processing engineering. Using resins as a binder, several fire-resistant prototypes were prepared from polyester waste, and their mechanical properties, thermal stability, and fire-resistant properties were analyzed.

Thermal Degradation of Copolymers of N‐Vinylcarbazole with Acrylic and Methacrylic Monomers

The thermal stability of several series of N‐vinylcarbazole and a methacrylic or acrylic monomer has been studied. The copolymers are more stable the higher the content of N‐vinylcarbazole, a few units of this monomer being capable of appreciably enhancing the thermal stability of the acrylic or methacrylic homopolymer. The degradation products have been analyzed by FTIR, and a degradation mechanism similar to that for the homopolymers has been proposed. The kinetic analysis based on a differential theoretical model, has allowed an estimate of the activation energy of the degradation process.