British Polymer Journal 

Abstract: It is argued that one can envisage two extreme regimes in rubber. The first is a dilute regime, where crosslinks are the only significant interaction between chains, and is the conventional model. The other extreme is one in which a very entangled situation exists where the chain statistics under deformation are remote from free Gaussian statistics. This latter case is studied and it is argued that the entropy per crosslink takes the form where α and β are independent of deformation but depend on temperature and density, and J2 is the usual first invariant. The dilute regime is α = β = 0.

Abstract: A method for the formation of monodisperse polystyrene (PS) and polymethylmethacrylate (PMMA) spheres, in the micron diameter range, was developed. The polymerisation reaction was carried out in a series of alcohols, using homo- and co-polymers as steric stabilisers in combination with a quaternary ammonium salt which probably acts as an electrostatic co-stabiliser. Monodisperse PS spheres were formed in the particle size range of 1–6 μm, by a single step process. The size range could be extended by further addition of monomer to the reaction mixture during the polymerisation. The solubility parameter of the alcohol used and the nature of the surfactant determine the diameter of the resulting spheres. However, the concentration of surfactant did not seem to affect strongly the size of the spheres but only the dispersity.

Abstract: Several different series of rigid and flexible polyesters with main chain liquid crystalline units were prepared and their properties were examined in relation to their structures. The first group of polymers were rigid aromatic copolyesters with mesogenic groups based on either chloro or methyl hydroquinone terephthalate units combined with varying amounts of different types of bisphenol terephthalate units The bisphenol comonomers used contained the structure: in which X was none, C(CH3)2, CH2, O, S, and So2. It was observed that the bisphenols with the bulkier X group were more efficient in destroying thermotropic liquid crystallinity of the resulting copolymers. The second group of polymers studied were flexible polyesters consisting of various types of mesogenic units which were connected together by different lengths of polymethylene flexible spacers. The liquid crystalline behaviours of these polymers, particularly their transition temperatures, were correlated with their structures. A brief review of previous studies on the synthesis of thermotropic liquid crystalline polyesters is included.

Abstract: Sulfonation et neutralisation controlees de PEEK, caracterisation de PEEK sulfone et effet de cette modification sur la cristallinite, les transitions thermiques et la stabilite thermique