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The kinetics of phase separation and crystallization in the blends of poly(ethylene-ran-hexene) (PEH) and poly(ethylene-ran-octene) (PEOC) at several compositions were studied using phase contrast optical microscopy and time-resolved simultaneous small-angle X-ray scattering and wide-angle X-ray diffraction. The phase contrast optical microscopy showed the interconnected bicontinuous structure during...
Blends were prepared from a high density polyethylene (PE) material and a conductive polycarbonate (PC) composite containing multiwalled carbon nanotubes (MWNT). The PC composite contained 2wt% MWNT and was prepared by diluting a PC masterbatch consisting of 15wt% MWNT by melt mixing in an extruder. The aim of blending a conductive PC composite with PE was to obtain a conductive blend at lower amounts...
The thermo-oxidative degradation of poly(ethylene glycol)/poly(l-lactic acid) (PEG/PLLA) blends was studied by infra-red spectroscopy (IR), differential scanning calorimetry (DSC), gel permeation chromatography (GPC) and thermogravimetry (TGA). The thermo-oxidative degradation of PEG occurred after a period time of aging in air at 80 °C. The mechanism of thermo-oxidative degradation of PEG was found...
Sequential networks made of hydroxypropylcellulose (HPC) and poly(N-isopropylacrylamide) (PNIPA) were synthesized by adsorption of a solution of NIPA monomer into a dried porous HPC network. NIPA polymerization inside the network allows us to obtain IPN which show, as the neat components, thermosensitive volumetric behavior. The volumetric transition temperatures range between those of HPC and PNIPA...
The glass transition and the crystallinity of blends of isotactic bacterial PHB and low molecular mass atactic R, S-PHB-diols was investigated by means of differential scanning calorimetry (DSC), temperature-modulated DSC and dielectric spectroscopy. It was found that (i) T g of crystallized blends is much lower than T g of quenched blends, (ii) the semi-crystalline blends can only...
Crystallization kinetics and morphology in miscible blends of syndiotactic polystyrene (sPS) and atactic postyrene (aPS) have been investigated by means of time-resolved depolarized light scattering (DPLS), polarized optical microscopy (POM) and scanning electron microscopy (SEM). Two different weight-average molecular weight of aPS, i.e. M w =100k and 4.3k, were used to prepare the blends...
Monte Carlo simulations were used to investigate the compatibilizing effects of diblock copolymers in A/B/A-B diblock copolymer ternary blends and triblock copolymers in A/B/triblock copolymer ternary blends, respectively. The volume fraction of homopolymer A was 19% and was the dispersed phase. The simulation results show that diblock copolymers with longer A-blocks are more efficient as compatibilizers,...
The effect of chain microstructure on adhesion of ethylene copolymers to polypropylene (PP) was studied using coextruded microlayers. Adhesion was measured by delamination toughness G using the T-peel test, and interfacial morphology was examined by atomic force microscopy. Good adhesion to PP was achieved with homogeneous metallocene catalyzed copolymers (mPE) with density 0.90 g cm -3 ...
The effect of end groups (2OH, 1OH, 1CH 3 and 2CH 3 ) of poly(ethylene glycol) (PEG) on the miscibility and crystallization behaviors of binary crystalline blends of PEG/poly(l-lactic acid) (PLLA) were investigated by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). A single glass-transition temperature was observed in the DSC scanning trace of the blend...
In this paper, the model based on melt diffusion and Flory-Huggins free energy theory for predicting the weld-line strength of injection molded amorphous polymers and polymer blends parts were modified by considering the diffusion thickness in the interface as a function of contact time. The modified model for weld-line strength prediction of homopolymers and polymer blends were, respectively, used...
Cloud-point curves of blends of poly(methyl methacrylate) (PMMA) with a series of oligodiols based on a bisphenol A nucleus and short branches of poly(ethylene oxide) or poly(propylene oxide) (BPA-EO or BPA-PO), and with PEO and PPO oligomers, were obtained using a light transmission device. Experimental results were fitted with the Flory–Huggins model using an interaction parameter depending on both...
Samples of propylene-ethylene (EP) and propylene-(1-butene) (BP) random copolymers with various comonomer content (2–3.1wt% ethylene, 9.9wt% 1-butene), were melt-mixed in Brabender internal mixer at various compositions (25/75, 50/50, 75/25). Films of copolymers and blends, as well as of a homopolymer sample (iPP), obtained by compression moulding and with different thermal history were characterized...
This paper describes a new reactive blending approach to improve the compatibility of poly(l-lactide) (PLLA) and poly(ɛ-caprolacton) (PCL). For this purpose, the ring-opening polymerization of l-lactide (LLA) was carried out in the presence of PCL-OH (OH groups on one end). The P(CL-b-LLA) block copolymers were in situ formed during polymerization, and as a result, PLLA/P(CL-b-LLA) blends were obtained...
The phase morphology developed in immiscible polypropylene (PP)/polycyclohexylmethacrylate (PCHMA) blends has been studied using an in situ reactively generated polystyrene-graft-polypropylene compatibilizer from maleic anhydride grafted polypropylene (MA-g-PP) and amine end-capped polystyrene (PS-NH2) reactive precursors during melt-blending. The imidation reaction responsible for the formation of...
New miscible blend systems comprised of poly(4-vinyl phenol) (PVPh) and a homologous series of polyesters of different CH 2 /CO ratios (from 4.5 to 7) was discovered. Miscibility has been confirmed using differential scanning calorimetry, Fourier-transformed infrared spectroscopy, and scanning electron microscopy. The PVPh/polyesters blends investigated exhibited a single composition-dependent...
When immiscible polymer melts are combined by chaotic advection, melt domains are recursively stretched and folded. A multi-layer blend morphology results that has a hierarchical structure and intrinsic mechanical interlocking. Novel derivative morphologies can be obtained via the formation and interactive growth of holes among melt layers. In this study, a unique continuous chaotic advection blender...
Polystyrene (PS, M n =28,400, PI=1.07), poly(methyl methacrylate) (PMMA, M n =88,600, PI=1.03), and PS (50,000)-b-PMMA (54,000) (PI=1.04), were used as modifiers of an epoxy formulation based on diglycidyl ether of bisphenol A (DGEBA) and m-xylylene diamine (MXDA). Both PS and PMMA were initially miscible in the stoichiometric mixture of DGEBA and MXDA at 80°C, but were phase separated...
Solution and melt blends have been prepared by mixing polyamide 6 (PA6) with hyperbranched (HB) aromatic polyamides (aramids) synthesized from A 2 (p-phenylenediamine)+B 3 (trimesic acid) reactants. The HB aramids (pPDT), were obtained using various polymerization conditions, hence were characterized by different content and ratio of –COOH and –NH 2 end group functionalities,...
We employed thin film blends of diblock copolymers with functional homopolymers as a simple strategy to incorporate organic functional materials into nanodomains of diblock copolymers without serious synthesis. A blend pair of polystyrene–poly(methyl methacrylate) (PS–PMMA) diblock copolymers and poly(vinylidene fluoride) (PVDF) was selected as a model demonstration because PVDF is a well-known ferroelectric...
Two methods to improve the dispersion, interfacial adhesion and properties of polymer mixtures are presented. Infrared spectroscopy and optical microscopy results document that control of the spacing of interacting moieties along the polymer chain results in optimal intermolecular hydrogen bonding and improved miscibility between two polymers. Moreover, initial results indicate that this protocol...
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