Immobilized Me2Si(C5Me4)(N-tBu)TiCl2/(nBuCp)2ZrCl2 hybrid metallocene catalyst system for the production of poly(ethylene-co-hexene) with pseudo-bimodal molecular weight and inverse comonomer distribution

2007 ◽  
Vol 47 (2) ◽  
pp. 131-139 ◽  
Author(s):  
Sung Chul Hong ◽  
Shahram Mihan ◽  
Dieter Lilge ◽  
Lourant Delux ◽  
Ursula Rief
Keyword(s):  
Molecular Weight ◽  
Metallocene Catalyst ◽  
Catalyst System ◽  
Poly Ethylene

A Brønsted Acidic Ionic Liquid as an Efficient and Selective Catalyst System for Bioderived High Molecular Weight Poly(ethylene 2,5‐furandicarboxylate)

ChemSusChem ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4927-4935 ◽  
Author(s):  
Xiao‐ling Qu ◽  
Min Jiang ◽  
Bing Wang ◽  
Jin Deng ◽  
Rui Wang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Ionic Liquid ◽  
High Molecular Weight ◽  
Catalyst System ◽  
Selective Catalyst ◽  
Acidic Ionic Liquid ◽  
Brønsted Acidic Ionic Liquid ◽  
Poly Ethylene ◽  
High Molecular Weight Poly

New Polyolefin Elastomers Containing “Reactive” p-Methylstyrene Units: Preparation by Metallocene Catalysts

1999 ◽  
Vol 72 (2) ◽  
pp. 283-298 ◽  
Author(s):  
T. C. Chung ◽  
H. L. Lu ◽  
S. Hong
Keyword(s):  
Molecular Weight ◽  
Metallocene Catalyst ◽  
The Other ◽  
Metallocene Catalysts ◽  
Scanning Calorimetry ◽  
Ethylene Propylene ◽  
Other Hand ◽  
Wide Range ◽  
Natta Catalyst ◽  
Poly Ethylene

Abstract This paper summarizes the experimental results of three new polyolefin elastomers, i.e., poly(1-octene-co- p-methylstyrene (O-p-MS), poly(ethylene-ter-propylene-ter-p-methylstyrene) (EP-p-MS) and poly(ethylene-ter-1-octene-ter-p-methylstyrene) (EO-p-MS), containing “reactive” p-MS units. Both Ziegler-Natta and metallocene catalysts were used in studying co- and ter-polymerization reactions. In the copolymerization of 1-octene and p-MS, Ziegler-Natta catalyst TiCl3/AlEt3 exhibits higher catalyst reactivity to produce high molecular weight O-p-MS copolymers, containing up to 20 mol % p-MS. However, the copolymers show very broad composition and molecular weight distributions. On the other hand, two EP-p-MS and EO-p-MS terpolymers with narrow molecular weight and composition distributions were prepared by [C5Me4(SiMe2NtBu)]TiCl2 metallocene catalyst with constrained ligand geometry. The sharp glass transition temperature (Tg) with flat baseline in each differential scanning calorimetry (DSC) curve indicates homogeneous terpolymer microstructures. The Tg of EP-p-MS is very sensitive to the terpolymer composition (ethylene/propylene ratio and p-MS content). In the compositions with ideal ethylene/propylene ratio ∼ 55/45, the Tα is almost proportional to the content of p-MS. Only with the concentration of p-MS < 2 mol %, does the EP-p-MS show alow Tg<−45°C. On the other hand, the EO-p-MS system exhibits a low Tg<−50°C in a wide range of copolymer compositions, even ones with relatively high p-MS contents (< 7 mol %).

The Structure of Radiation Cross-Linked Poly (ethylene oxide) Gels

1971 ◽  
Vol 29 ◽  
pp. 76-77
Author(s):  
C. E. Cluthe ◽  
G. G. Cocks
Keyword(s):  
Molecular Weight ◽  
Ethylene Oxide ◽  
Parallel Plate ◽  
Average Molecular Weight ◽  
Radical Reaction ◽  
Free Radical Reaction ◽  
Nitrogen Gas ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Initial Viscosity

Aqueous solutions of a 1 weight-per cent poly (ethylene oxide) (PEO) were degassed under vacuum, transferred to a parallel plate viscometer under a nitrogen gas blanket, and exposed to Co60 gamma radiation. The Co60 source was rated at 4000 curies, and the dose ratewas 3.8x105 rads/hr. The poly (ethylene oxide) employed in the irradiations had an initial viscosity average molecular weight of 2.1 x 106.The solutions were gelled by a free radical reaction with dosages ranging from 5x104 rads to 4.8x106 rads.

Fractionation and molecular weight determination of poly(ethylene glycol methacrylate)

1968 ◽  
Vol 33 (12) ◽  
pp. 4104-4110 ◽  
Author(s):  
M. Bohdanecký ◽  
Z. Tuzar ◽  
M. Štoll ◽  
R. Chromeček
Keyword(s):  
Molecular Weight ◽  
Ethylene Glycol ◽  
Molecular Weight Determination ◽  
Poly Ethylene Glycol ◽  
Glycol Methacrylate ◽  
Poly Ethylene

scholarly journals Isothermal Crystallization Kinetics of Poly(ethylene oxide)/Poly(ethylene glycol)-g-silica Nanocomposites

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 648
Author(s):  
Xiangning Wen ◽  
Yunlan Su ◽  
Shaofan Li ◽  
Weilong Ju ◽  
Dujin Wang
Keyword(s):  
Molecular Weight ◽  
Ethylene Oxide ◽  
Crystallization Kinetics ◽  
Isothermal Crystallization ◽  
Crystallization Rate ◽  
Poly Ethylene Glycol ◽  
Isothermal Crystallization Kinetics ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Kinetics Of

In this work, the crystallization kinetics of poly(ethylene oxide) (PEO) matrix included with poly(ethylene glycol) (PEG) grafted silica (PEG-g-SiO2) nanoparticles and bare SiO2 were systematically investigated by differential scanning calorimetry (DSC) and polarized light optical microscopy (PLOM) method. PEG-g-SiO2 can significantly increase the crystallinity and crystallization temperature of PEO matrix under the non-isothermal crystallization process. Pronounced effects of PEG-g-SiO2 on the crystalline morphology and crystallization rate of PEO were further characterized by employing spherulitic morphological observation and isothermal crystallization kinetics analysis. In contrast to the bare SiO2, PEG-g-SiO2 can be well dispersed in PEO matrix at low P/N (P: Molecular weight of matrix chains, N: Molecular weight of grafted chains), which is a key factor to enhance the primary nucleation rate. In particular, we found that the addition of PEG-g-SiO2 slows the spherulitic growth fronts compared to the neat PEO. It is speculated that the interfacial structure of the grafted PEG plays a key role in the formation of nuclei sites, thus ultimately determines the crystallization behavior of PEO PNCs and enhances the overall crystallization rate of the PEO nanocomposites.

Capillary electrophoretic separation of high-molecular-weight poly(ethylene glycol)-modified proteins

2008 ◽  
Vol 373 (2) ◽  
pp. 207-212 ◽  
Author(s):  
Dong Hee Na ◽  
Eun Ji Park ◽  
Yeong Woo Jo ◽  
Kang Choon Lee
Keyword(s):  
Molecular Weight ◽  
Ethylene Glycol ◽  
High Molecular Weight ◽  
Electrophoretic Separation ◽  
Poly Ethylene Glycol ◽  
Capillary Electrophoretic ◽  
Modified Proteins ◽  
Poly Ethylene ◽  
High Molecular Weight Poly
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