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Isothermal crystallization and morphology of G-resin (GPP) and isotactic polypropylene (iPP) samples were investigated and compared using synchrotron small-and wide-angle X-ray scattering/diffraction (SAXS/WAXD) and differential scanning calorimetry (DSC). Two GPP resins (MT12-s and MT18-s) are iPP containing a small amount of 1-butene. All polymers have similar MW and PDI, denoted by V30G, MT12-s, and MT18-s with 1-butene = 0.00, 6.43, and 5.20 wt%, respectively. DSC isothermal crystallization at 130 C showed that the crystallinity of G resins were lower, but the crystallization rate of G resins was faster in the order as MT18-s ≥ MT12-s > V30G. Simultaneous synchrotron SAXS/WAXD was employed to determine polymer morphology crystallized from the melt. The electron density correlation function was calculated to estimate the lamellar thickness. The long periods (D) are around 19.0, 25.8, and 25.8 nm for V30G, MT12-s, and MT18-s, respectively. The GPP samples have a larger amorphous portion and a higher crystalline thickness (L) but a lower L/D ratio than IPP. The degree of crystallinity by WAXD is also smaller for GPP, that is, MT18-s (31%) ≈ MT12-s (31%) < V30G (>50%). In addition to the monoclinic α forms for all the PP samples, the orthorhombic γ forms were found only for MT12-s and MT18-s. The crystallization of G-resins should be nucleated from the transparent filler and are not fully an intrinsic property of the copolymer chains.

An efficient technique to construct dense amorphous polymers at the bulk density is illustrated for two vinyl polymers, i.e., PVX, –[CH2–CH(X)]–. Bulk amorphous polypropylene (PP) and polystyrene (PS) structures are generated starting from coarse‐graining polymer chains and are mapped onto the second nearest neighbor diamond (2nnd) lattice. PVX are represented by the rotational isomeric state (RIS) model and non‐bonded interactions are treated by the Lennard–Jones (LJ) potential function. Lattice Monte Carlo (MC) simulation is utilized to equilibrate coarse‐grained (C) PVX and the fully atomistic models can be recovered by the reverse‐mapping procedure to restore the missing atoms. After geometry optimization, chain and material properties of bulk PVX structure are computed to validate the atomistic models including conformational characteristics, Hildebrand solubility parameter, pair correlation function, and scattering structure factor.

For moderately entangled high-cis polyisoprene (molecular weight = 30.5 × 103 ) head-modifi ed with an associative metal-carboxylate (salt) group, PI30-COOM with M = Li, Na, and K, linear viscoelastic and dielectric measurements were conducted to examine an effect(s) of the head-to-head association on the chain dynamics. The PI30-COOM chains had type-A dipoles so that their large-scale dynamics was refl ected in both viscoelastic and dielectric data at low angular frequencies. The salt groups associate and dissociate (without ionization) with a rate that changes with the temperature T, as known for ionomers having non-polar backbones. Correspondingly, PI30-COOM exhibited failure of the time-temperature superposition for both viscoelastic and dielectric data. This failure was characterized through comparison with non-associative reference homo-PI, the PI30 unimer (a precursor of PI30-COOM), (PI30) 2 dimer, and (PI30) 6 star-type hexamer. It turned out that the viscoelastic data of PI30-COOLi at low and intermediate T (−20 º and 20 ºC), respectively, were close to those of the star-hexamer and dimer data in the iso-frictional state, and a further increase of T resulted in deviation from the dimer data toward the unimer data. This "crossover" was observed also for PI30-COONa and PI30-COOK but at lower T, which possibly reflected a barrier for the dissociation of the COOM groups lowering in the order of COOLi > COONa > COOK. The dielectric data of PI30-COOM showed a qualitatively similar crossover but at higher T compared to the viscoelastic crossover. This difference between the viscoelastic and dielectric behavior was discussed in relation to the dynamic tube dilation mechanism and also to the motional coupling (conformational transfer) among the PI30-COOM chains coexisting in different association forms.