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Impact-resistant polypropylene copolymer (IPC) samples with various pre-shear histories were prepared by a Brabender Rheometer. The influence of pre-shearing on crystallization of IPC, including isothermal and nonisothermal crystallization behaviors was investigated by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). The results of nonisothermal crystallization showed...
Shish–kebab morphologies were observed with relatively low shear rate and low temperature in the phase-separated isotactic polypropylene (iPP) and high density polyethylene (HDPE) blend. Both components are crystallizable polymers. In our experiments, relatively low shear rates and low temperatures were used, so that the entangled network chains cannot be broken up or disentangled, and the shish nuclei...
A series of polyethylene (PE) blends consisting of a linear high density polyethylene (HDPE) and a linear low density polyethylene (LLDPE) with an octane-chain branch density of 120/1000 carbon was prepared at different concentrations. The two components of this set of blends possessed isorefractive indices, thus, making it difficult to detect their liquid–liquid phase separation via scattering techniques...
A basic problem with many promising solid electrolyte materials for battery applications is that crystallization in these materials at room temperature makes ionic mobilities plummet, thus compromising battery function. In the present work, we consider the use of a polymer additive (polyethylene oxide, PEO) to inhibit the crystallization of a promising battery electrolyte material, the organic crystal...
The thin films of a symmetric crystalline-coil diblock copolymer of poly(l-lactic acid) and polystyrene (PLLA-b-PS) formed lamellae parallel to the substrate surface in melt. When annealed at temperatures well above the glass transition temperature of PLLA block (T gPLLA ), the PLLA chains started to crystallize, leading to reorientation of lamellae. Such reorientation behavior exhibited...
The solid-state morphology of polystyrene-poly(ethylene oxide) metallo-supramolecular diblock copolymer PS 20 -[Ru]-PEO 70 , has been investigated by small-and wide-angle X-ray scattering and atomic force microscopy. Above the melting point of PEO the metal–ligand complexes and their associated counter ions are known to form aggregates within the still disordered polymer matrix of...
Miscibility, crystallization kinetics, crystal structure, and microstructure of biodegradable poly(butylene succinate-co-butylene adipate) (PBSA)/poly(vinyl phenol) (PVPh) blends were studied by differential scanning calorimetry, optical microscopy, wide angle X-ray diffraction, and small angle X-ray scattering in detail in this work. PBSA and PVPh are miscible as evidenced by the single composition...
In this paper the comonomer distributions of two series of ethylene–propylene copolymers with different propylene contents, which were prepared by a fluorinated bis(phenoxyimine) Ti catalyst (FI–EP copolymers) and a conventional Ziegler–Natta catalyst (ZN–EP copolymers), respectively, were characterized. It is found that the comonomer distribution of ethylene–propylene copolymers can still be characterized...
The present work is concerned with the study of the development of the crystalline structure of poly(ethylene terephthalate) in multilayered films of poly(ethylene terephthalate)/polycarbonate (PET/PC) prepared by means of layer multiplying coextrusion. Small angle X-ray scattering patterns were recorded during isothermal crystallization experiments and evaluated by means of Ruland's interface distribution...
A two stage growth during isothermal cold crystallization of PHB has been observed in the temperature range 5–40°C when a free surface is present. This growth has been investigated with optical and atomic force microscopy both in-situ and ex-situ. Initially, crystal growth is observed to be composed of lamellae oriented approximately flat-on relative to the free surface. At later stages of growth...
The effects of incorporated amorphous poly(dl-lactide) (PDLLA) on the isothermal crystallization and spherulite growth of crystalline poly(l-lactide) (PLLA) and the structure of the PLLA/PDLLA blends were investigated in the crystallization temperature (T c ) range of 90–150°C. The differential scanning calorimetry results indicated that PLLA and PDLLA were phase-separated during crystallization...
Cast films of a high molecular weight linear polypropylene (L-PP) were prepared by extrusion followed by stretching using a chill roll. An air knife was employed to supply air to the film surface right at the exit of the die. The effects of air cooling conditions, chill roll temperature, and draw ratio on the crystalline orientation, morphology, mechanical and tear properties of the PP cast films...
By focusing on a range of fractions of medium-chain-length polyhydroxyalkanoates (mcl-PHA), a more in-depth understanding of the thermal properties and the crystalline structure has been gained. Dual-mode melting was observed for all the fractionated samples. Further DSC analysis revealed that such phenomenon was due to the presence of two crystalline phases (phase I and phase II), forming at different...
Over the past two decades atomic force microscopy (AFM) has become one of the most frequently used tools for studying polymer crystallization. The combination of high resolution, minimal sample preparation and the ability to image non-destructively has allowed visualisation of crystallization, melting and re-ordering processes at a lamellar and sub-lamellar scale, revealing complexities that could...
To understand the effect of the montmorillonite (MMT) particles on the crystallization kinetics and crystalline morphology of nylon 6 upon nano-composite formation, we have characterized the crystallization behaviors by using light scattering, wide-angle X-ray diffraction (WAXD), transmission electron microscope (TEM) and rheological measurement. The correlation between the nucleating effect and the...
In the previous papers, we elucidated enhancement of concentration fluctuations, phase separation, and crystallization induced by steady state or step-up shear flow, as observed by shear small-angle light scattering, optical microscopy, and birefringence, for a semidilute solution of ultrahigh molecular weight polyethylene in paraffin as an athermal solvent. However the studies were done only at a...
The morphology of two polypropylene/poly(ethylene-co-propylene) (PP/EPR) in-reactor alloys prepared by multi-stage sequential polymerization (MSSP) and two-stage polymerization (TSP) processes, respectively, was investigated. It is observed that the alloy prepared by MSSP (sample 1) exhibits lower phase separation temperature than the alloy prepared by TSP (sample 2), probably due to the higher content...
The effect of random insertion of low amount of 1-butene of less than about 11mol% into the isotactic polypropylene chain on structure formation at non-isothermal crystallization at different rate of cooling was investigated by X-ray scattering, density measurements, and atomic force and polarizing optical microscopy. Emphasis is put on the evaluation of the condition of crystallization for replacement...
The isothermal crystallization of syndiotactic polypropylene (sPP) was investigated by in situ Fourier transform infrared spectroscopy (FTIR) and wide angle X-ray diffraction (WAXD). It was found that the ordered helical structure developed during the induction period of the isothermally crystallization of sPP. Moreover, the normalized intensity profiles of the characteristic FTIR absorption bands...
Isotactic polypropylene (iPP) with “disentangled” chains was generated through crystallization of iPP from its mineral oil solution. TGA test assured complete removal of mineral oil from iPP precipitates. Time sweep rheological measurements showed the modulus build-up with time indicating the formation of “disentangled” chains in iPP after the sample disentanglement treatment. The “disentangled” chains...
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