Crystallization Kinetics of Low Molecular Weight Fractions of Branched Polyethylenes

1994 ◽  
Vol 27 (13) ◽  
pp. 3537-3542 ◽  
Author(s):  
W. Scott Lambert ◽  
Paul J. Phillips
Keyword(s):  
Molecular Weight ◽  
Crystallization Kinetics ◽  
Low Molecular Weight ◽  
Kinetics Of ◽  
Molecular Weight Fractions

scholarly journals The Kinetics of Two-Step Ellagitannin Extraction from the By-products of Selected Processed Fruits of the family Rosaceae

2021 ◽  
Author(s):  
Agnieszka Milczarek ◽  
Michał Sójka ◽  
Robert Klewicki
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
Fruit Species ◽  
Definite Effect ◽  
Extraction Step ◽  
The Family ◽  
The Mean ◽  
Berry Fruits ◽  
Kinetics Of ◽  
Molecular Weight Fractions

AbstractThe paper presents the kinetics of two-step ellagitannin (ET) extraction with an aqueous acetone solution from two technological types of pomace from selected berry fruits of the Rosaceae family. ETs were identified and quantified using HPLC–MS and HPLC–DAD. The results revealed the extraction kinetics of total ETs, their high and low molecular weight fractions (≤ 1569 Da and > 1569 Da), and individual ETs characteristic of the examined fruits. ET extraction proceeded at a faster rate in the first step, regardless of the tested pomace. For all pomace variants, the mean extraction half time t1/2 was 48 min in the first step and 70 min in the second step. The fruit species and the technological type of pomace were not found to exert a definite effect on the kinetics of ET extraction. Statistical analysis demonstrated that the molecular weight of ETs did not influence the kinetics of their extraction, either. It was shown that the technological type of pomace had a significant impact on the extraction rate of both low molecular weight (LMW) and high molecular weight (HMW) ETs in the first extraction step, with the mean t1/2 being 44 min for pomace from juice production and 63 min for pomace from puree production.

The crystallization kinetics of low-molecular-weight polyethylene fractions

Polymer ◽  
1990 ◽  
Vol 31 (5) ◽  
pp. 890-898 ◽  
Author(s):  
J.G Fatou ◽  
C Marco ◽  
L Mandelkern
Keyword(s):  
Molecular Weight ◽  
Crystallization Kinetics ◽  
Low Molecular Weight ◽  
Kinetics Of

Applications of Algal Polysaccharides and Derivatives in Therapeutic and Agricultural Fields

2019 ◽  
Vol 25 (11) ◽  
pp. 1187-1199 ◽  
Author(s):  
Soukaina Bouissil ◽  
Guillaume Pierre ◽  
Zainab El Alaoui-Talibi ◽  
Philippe Michaud ◽  
C. El Modafar ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Wound Dressing ◽  
Chemical Processes ◽  
Bioactive Molecules ◽  
Present Review ◽  
Agricultural Fields ◽  
Low Molecular Weight ◽  
Molecular Weight Fractions ◽  
Algal Polysaccharides ◽  
Agricultural Fertilizer

Background: Recently, researchers have given more and more consideration to natural polysaccharides thanks to their huge properties such as stability, biodegradability and biocompatibility for food and therapeutics applications. Methods: a number of enzymatic and chemical processes were performed to generate bioactive molecules, such as low molecular weight fractions and oligosaccharides derivatives from algal polysaccharides. Results: These considerable characteristics allow algal polysaccharides and their derivatives such as low molecular weight polymers and oligosaccharides structures to have great potential to be used in lots of domains, such as pharmaceutics and agriculture etc. Conclusion: The present review describes the mains polysaccharides structures from Algae and focuses on the currents agricultural (fertilizer, bio-elicitor, stimulators, signaling molecules and activators) and pharmaceutical (wound dressing, tissues engineering and drugs delivery) applications by using polysaccharides and/or their oligosaccharides derivatives obtained by chemical, physical and enzymatic processes.

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.

Kinetics of the reaction of the first metabolite of fenitropan with some low molecular weight thiols

1989 ◽  
Vol 26 (3) ◽  
pp. 253-259 ◽  
Author(s):  
Gabor Gullner ◽  
Gyula Josepovits ◽  
Gyula Mikite
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
Kinetics Of
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