A series of poly(cyclohexylethylene-b-ethylene-coethylethylene) (C-E/E E ) diblock copolymers containing approximately 50% by volume glassy C blocks and varying fraction (x) of E E repeat units, 0.07x 0.90, was synthesized by anionic polymerization and catalytic hydrogenation. The effects of ethyl branch content on the melt state segment-segment (v) interaction parameter and soft (E/E E ) block crystallinity were studied. The percent crystallinity ranged from approximately 30% at x ¼ 0.07 to 0% at about x ! 0.30, while the melting temperature changed from 101 C at x ¼ 0.07 to 44 C at x ¼ 0.28. Dynamic mechanical spectroscopy was employed to determine the order-disorder transition (ODT) temperatures, from which v was calculated assuming the mean-field prediction (vN n ) ODT ¼ 10.5. Previously published results for the temperature dependent binary interaction parameters for C-E (x ¼ 0.07), C-E E (x ¼ 0.90), and E-E E (x ¼ 0.07 and x ¼ 0.90) fail to account for the quantitative x dependence of v, based on a simple binary interaction model.

A new series of monoepoxide terminated controlled epoxy networks (CENs) and a corresponding soluble fraction polymer (SFP) were prepared to further investigate the effects of chain termination on epoxy thermoset structure-property relationships. CENs having an initial molecular weight between crosslinks (M c,i ) of $3000 g/mol using phenylglycidyl ether (PGE) as the chain terminator have thermal and mechanical properties consistent with previously studied monophenol terminated CENs. Glass transition temperature (T g ) decreases monotonically with PGE concentration (e), whereas fracture toughness decreases sharply at a critical PGE concentration (e c ). A PGE terminated SFP was prepared corresponding to the soluble fraction expected for the CEN composition at e c . The SFP behaves as a weak antiplasticizer in these epoxy thermosets; T g is reduced and follows the inverse rule of mixtures, and fracture toughness is slightly reduced. By difference it is inferred that most of the deterioration of epoxy thermoset properties resulting from incorporation of chain terminators above e c is a result of the presence of nonelastically active pendant chains and by the increase in M c .

The bulk mechanical properties of linear triblock and pentablock copolymers that self-assemble into hexagonally packed cylinders with glassy, unentangled matrices of poly(cyclohexylethylene) (PCHE for a homopolymer, C for a block copolymer) with rubbery poly(ethylene-alt-propylene) (P) and semicrystalline polyethylene (E) minority components are examined. The tensile properties of high C content CEC triblock copolymer could not be quantified; however, CPC can plastically deform under uniaxial strain, unlike brittle PCHE. Both CECEC and CPCPC pentablock copolymers exhibited ductile tensile behavior, but the tensile properties of blends of these two penta-block copolymers show that the addition of crystallinity in the minority phase prevents strain softening after yielding and necking, which indicates that these samples deform only via crazing. On the other hand, the white gage region of CPCPC and the ability of CPCPC to neck indicate that high C content materials deform via shear yielding and crazing when the minority component is a rubbery material. V C 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 50: [706][707][708][709][710][711][712][713][714][715][716][717] 2012