scholarly journals Effects of Geometrical Difference of Unsaturated Aliphatic Polyesters on Their Biodegradability III. Cross Effects of Molecular Weight and Geometric Structure of Poly(ethylene maleate/fumarate) and Its Model Compounds

2002 ◽  
Vol 34 (12) ◽  
pp. 882-890
Author(s):  
Shigenobu Takenouchi ◽  
Akinori Takasu ◽  
Yoshihito Inai ◽  
Tadamichi Hirabayashi
Keyword(s):  
Molecular Weight ◽  
Geometric Structure ◽  
Model Compounds ◽  
Aliphatic Polyesters ◽  
Poly Ethylene ◽  
Geometrical Difference

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.

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

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

scholarly journals Isothermal Thickening and Thinning Processes in Low-Molecular-Weight Poly(ethylene oxide) Fractions Crystallized from the Melt. 8. Molecular Shape Dependence. Volume 32, Number 15, July 27, 1999, pp 4784−4793.

1999 ◽  
Vol 32 (15) ◽  
pp. 5174-5174
Author(s):  
Er-Qiang Chen ◽  
Song-Wook Lee ◽  
Anqiu Zhang ◽  
Bon-Suk Moon ◽  
Ian Mann ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Ethylene Oxide ◽  
Molecular Shape ◽  
Low Molecular Weight ◽  
Shape Dependence ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene

SEC/MALDI-TOF Mass spectrometry study of hydroxy-, carboxy- and methyl ester-terminated aliphatic polyesters

e-Polymers ◽  
2005 ◽  
Vol 5 (1) ◽  
Author(s):  
Slim Salhi ◽  
Martine Tessier ◽  
Jean-Claude Blais ◽  
Rachid El Gharbi ◽  
Alain Fradet
Keyword(s):  
Dimethyl Ester ◽  
Calibration Method ◽  
Size Exclusion ◽  
Aliphatic Polyesters ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Calibration Curves ◽  
End Groups ◽  
Poly Ethylene ◽  
Tof Ms

AbstractPoly(ethylene adipate) (PEA) and poly(ethylene dodecanedioate) (PED) with dicarboxy-, dihydroxy-, dimethyl ester- and hydroxy-carboxy end-groups were synthesized and characterized by 13C NMR and MALDI-TOF MS. Size-exclusion chromatography (SEC) fractions of these polyesters were analyzed by MALDI-TOF MS and used as standards to obtain SEC calibration curves leading to the absolute molar masses of the unfractionated polyesters. PEA and PED calibration curves were different from each other, but the same calibration curve was obtained for each type of polyester, irrespective of the nature of end-groups, showing the predominant role of the nature of repeating units on the hydrodynamic volume of oligoesters. The study also shows that the conventional SEC calibration method using polystyrene standards leads to a significant overestimation of polyester average molar masses.

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