Hydrogenated Oligo Cyclopentadiene Research Articles

A 1H and 13C Solid State NMR Investigation of the Structure and Molecular Dynamics of Hydrogenated Oligocyclopentadiene

The structure and dynamics of hydrogenated oligo(cyclopentadiene) (HOCP) was investigated by means of 1H and 13C NMR in the solid state. The 13C NMR spectrum of HOCP is reported and interpreted for...

Thermal and morphological analysis of isotactic poly(1-butene)/hydrogenated oligocyclopentadiene blends

This contribution discusses the influence of hydrogenated oligocyclopentadiene (HOCP) on the morphology, the phase structure and the thermal properties of its blends with isotactic poly(1-butene) (PB-1) as a function of composition and crystallization conditions. PB-1 and HOCP are partially miscible in the melt state. The blends, in the solid state, form generally a three-phase system: a crystalline phase formed by the polyolefin and two amorphous phases, of which one is rich in PB-1 and the other one in HOCP. The optical micrographs of the solidified blends show a morphology constituted by microspherulites and domains of HOCP-rich phase homogeneously distributed in intraspherulitic regions. Moreover, when the PB-1 and the blends are isothermally crystallized, hedrite-like crystallites are observed. The crystallization process and the melting behavior are strongly influenced by the presence of the oligomer, since the addition of HOCP decreases the overall crystallization rate and the melting point of the blends.

Morphology and Crystallization of Poly(4-Methylpentene-1) and Its Blends With Hydrogenated Oligocyclopentadiene

The paper discusses the morphology, melting behavior, and process of crystallization of poly(4-methylpentene-1) (P4MP1) and its blends with an amorphous oligomer, hydrogenated oligocyclopent-adiene (HOCP). The study was performed by using optical and electron microscopy, differential scanning calorimetry and X-ray scattering. In all ranges of compositions and temperatures investigated, P4MP1 and HOCP components were not miscible. The HOCP formed segregated domains in the P4MP1 matrix. Depending on thermal treatment, different melting behaviors and morphologies were obtained. In particular, varying the crystallization conditions and composition one or two populations of lamellae of different thickness formed. The half-time of crystallization drastically increased following the addition of HOCP. This increase was mainly accounted for by the additional energy required to perform the occlusion of the HOCP domains by the P4MP1 molecules during the crystallization.

Dynamical properties in glass forming polymers

Raman low-frequency depolarized light scattering measurements were performed on polymers, namely isotactic polypropylene (iPP), polyethylene (PE) and their blends with hydrogenated oligo cyclo pentadiene (HOCP) at the melting point. In the solid state these blends have a lamellar morphology, crystalline iPP layers alternating to amorphous iPP + HOCP layers. Detailed study of the experimental data showed the main role played by the effective vibrational density of states in comparison with the reorientational diffusion contribution. On the other hand the existence of a boson peak, characteristic of glass forming systems, whose centre-frequency shifts towards higher values, increasing the percentage of HOCP, denotes the disorder effect connected with the presence of this component in the polymeric blends, the occurrence of which is also shown by the evolution of the dynamical correlation length, R c. Furthermore, in the very low-frequency range a crossover ( ω co∼0.1 THz) from a spectral phonon-like contribution to a fracton-like contribution is detected.

Orientation and properties of sequentially drawn films of an isotactic polypropylene/ hydrogenated oligocyclopentadiene blend

Films of isotactic polypropylene (iPP) and a blend of iPP and hydrogenated oligocyclopentadiene (HOCP) oriented by one-way (uniaxial) and two-way (sequential biaxial) drawing were studied. The mechanical and thermal properties of the oriented iPP and iPP/HOCP blends as well as orientation behaviour were investigated by means of mechanical tests, d.s.c. and small- and wide-angle X-ray scattering including the pole figures technique. It was found that drawing of iPP/HOCP blends to a high strain leads to the formation of highly oriented films having mechanical properties greatly improved compared to plain iPP oriented under the same conditions. The studies revealed in one-way drawn samples the multicomponent texture with chain axis, c, oriented in the machine direction, MD, for all texture components. The lamellae are oriented with normals parallel to the c direction. Due to differences in the amorphous phase content the texture in the blend samples is less developed than in deformed plain iPP. The subsequent drawing along the transverse direction, TD, leads to the reorientation of the c axis towards the TD, the sharpening of texture and the destruction of the lamellar structure. It was found that the major deformation mechanisms active in iPP and iPP/HOCP blends are: the crystallographic slips systems of (010)[001], (100)[001], (110)[001] and {110} twinning modes. In addition the interlamellar sliding is active as the main deformation mechanism in the amorphous phase. The (010)[001] system is the easiest of the slip systems active and dominates the other mechanisms.

Small angle scattering study of the structure of isotactic polypropylene-hydrogenated oligo(cyclopentadiene) blends

Blends of isotactic polypropylene ( iPP) and hydrogenated oligo cyclopentadiene (HOCP) have been studied by means of small angle X-ray scattering in the temperature range 70–160°C. The structure of blends containing less than 25% HOCP is very similar to the one of plain iPP, i.e. lamellae whose thickness increases by increasing the temperature. Blends containing more than 25% HOCP are characterized by two kinds of lamellae formed by layers of iPP and amorphous material rich in iPP and in HOCP, respectively. The crystallizable iPP present in both phases crystallizes from the melt, in analogy to what happens in HDPE/HOCP blends and in agreement with the values of the crystallinity referred to the crystallizable polymer, that is almost constant with composition for both blends.

Blending polypropylene with hydrogenated oligocyclopentadiene: A new method for the production of dyeable fibers

Conventional direct dyeing techniques have limited use for the coloration of polypropylene fibers. In this paper, blends of isotactic polypropylene (iPP) with hydrogenated oligocyclopentadiene (HOCP), a glassy amorphous resin, have been used for the preparation of fibers dyeable in an aqueous dyebath. These fibers show better light, wet-washing and cleaning fastness properties than iPP while retaining similar statical mechanical properties.

Isotactic polypropylene/hydrogenated oligo(cyclopentadiene) blends: phase diagram and dynamic-mechanical behaviour of extruded isotropic films

The phase structure and the dynamic-mechanical properties of isotropic films of isotactic polypropylene iPP)/hydrogenated oligocyclopentadiene (HOCP) blends are reported. It is found that the phase diagram presents both the lower critical solution temperature and the upper critical solution temperature. The dynamic-mechanical tests (performed at a frequency of 1 Hz and at a heating rate of 4°C min −1) show that the addition of HOCP > 20 wt% causes an increase of the storage modulus at low temperatures; the curves of storage modulus and loss modulus of the isotropic films containing HOCP > 20 wt% show the transition of the smectic form of iPP to the crystalline α form.

Morphology, phase structure and thermal behaviour of films of isotactic polypropylene/hydrogenated oligocyclopentadiene blends: 1. Extruded isotropic films

The effect of hydrogenated oligocyclopentadiene (HOCP) on the structure and morphology of isotropic isotactic polypropylene (iPP) films obtained by melt extrusion has been studied using wide-angle X-ray scattering, thermal analysis and electron microscopy. It was found that the addition of HOCP causes the formation of the smectic phase of iPP at temperatures where bulk iPP crystallizes only in the monoclinic form. The amount of smectic phase present in the blend is dependent on the blend composition. The spherulitic morphology of iPP is completely modified by the presence of HOCP. For blends containing up to 10% HOCP, the iPP spherulite dimensions are drastically reduced. In the case of blends of higher HOCP content, the film crystallinity is reduced, no spherulites are visible and the film surface appears smoother.

Oxygen permeation through films of polypropylene/hydrogenated oligocyclopentadiene blends

Oxygen permeation through films of isotactic polypropylene (iPP)/hydrogenated oligocyclopentadiene (HOCP) blends was studied as a function of the weight fraction of the two components and temperature. Increasing HOCP content lowers oxygen permeability and diffusivity through the films and increases the glass transition temperature of the polymer blends. Activation energies for permeation and diffusion processes were also measured. Annealing for 2 min at 100°C was shown to completely transform the smectic phase in the α-crystalline form and to induce a marked increase in oxygen permeability and diffusivity, especially in the blends, and a corresponding decrease in the activation parameters.