Series of ethylene/1-alkene and ethylene-propylene-diene copolymers are separated with size exclusion chromatography (SEC) at 150°C using 1,2,4-trichlorobenzene as the mobile phase. Methyl (CH3–) methylene (–CH2–) groups in polymer samples monitored specific wavelengths via a filter-based infrared detector (IR5). It is found that ratio CH3/CH2 may increase, be constant, decrease or change irreg...

In the present work we aim to clarify the role of the microstructure and the crystalline distribution from the thermo-oxidation of solid isotactic PP (iPP) and ethylene-propylene (EP) copolymers. The effects of the content and quality of the isotacticity interruptions, together with the associated average isotactic length, on the induction time (ti) as well as on the activation energy (Eact) of...

The temperature and pH dependent self-assembly of three star shaped ethylene oxide-propylene oxide (EO-PO) block copolymers (Tetronics® 304, 904 and 908) with widely different hydrophobicity was examined in aqueous solutions. Physico-chemical methods viz. viscosity, cloud point, solubilization along with thermal, scattering and spectral techniques shows strongly temperature and salt dependent s...

Poloxamers F88 (EO97PO39EO97) and P85 (EO27PO39EO27) are triblock copolymers of ethylene oxide (EO) and propylene oxide (PO), which have the same hydrophobic PO block. We studied aqueous solutions of these two copolymers by the conjoint use of differential scanning calorimetry (DSC), rheology, and small-angle X-ray scattering (SAXS). The results showed that the temperature-induced micellization...

We report an effective strategy for the synthesis of semi-crystalline block copolyethers with well-defined architecture and stereochemistry. As an exemplary system, triblock copolymers containing either atactic (racemic) or isotactic (R or S) poly(propylene oxide) end blocks with a central poly(ethylene oxide) mid-block were prepared by anionic ring-opening procedures. Stereochemical control wa...

Until now, the leading polymer of intrinsic microporosity PIM-1 has become quite famous for its high membrane permeability for many gases in gas separation, linked, however, to a rather moderate selectivity. The combination with the hydrophilic and low permeable poly(ethylene glycol) (PEG) and poly(ethylene oxides) (PEO) should on the one hand reduce permeability, while on the other hand enhanc...

BACKGROUND Cationic copolymers consisting of polycations linked to nonionic amphiphilic block polymers have been evaluated as nonviral gene delivery systems, and a large number of different polymers and copolymers of linear, branched, and dendrimeric architectures have been tested in terms of their suitability and efficacy for in vitro and in vivo transfection. However, the discovery of new pot...

sio2-supported silyl chromate catalyst is an important industrial catalyst for production of high grade hdpepipe materials. the control of the short chain branch (scb) distribution using this catalyst system is still a greatchallenge. in this work, ethylene and 1-hexene copolymers were synthesized using sio2-supported silyl chromatecatalyst combined with triisobutylaluminium (tiba), triethylalu...

The new highly active supported vanadium-magnesium catalyst (VMC) has been studied in α-olefin (1-butene, 1-hexene)/ ethylene copolymerization in the presence of hydrogen. Data on the effect of α-olefin/ethylene ratio in copolymerization on the content of branchings in copolymers, kinetic profile, copolymer yield, molecular weight and molecular weight distribution of copolymers have been obtain...

Water vapor sorption in films consisting of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) amphiphilic block copolymers has been measured gravimetrically at air relative humidity in the range 38–94% at 248C. The water sorption isotherm was obtained and compared to data for water vapor desorption (drying) for the same system. The kinetics of water vapor sorption we...