Methods of long chain branching detection in PE by triple-detector gel permeation chromatography

2015 ◽  
Vol 132 (28) ◽  
pp. n/a-n/a ◽  
Author(s):  
Thipphaya Pathaweeisariyakul ◽  
Kanyanut Narkchamnan ◽  
Boonyakeat Thitisuk ◽  
Wallace Yau
Keyword(s):  
Gel Permeation Chromatography ◽  
Chain Branching ◽  
Long Chain Branching ◽  
Gel Permeation ◽  
Long Chain

An alternative method for long chain branching determination by triple-detector gel permeation chromatography

Polymer ◽  
2016 ◽  
Vol 107 ◽  
pp. 122-129 ◽  
Author(s):  
Thipphaya Pathaweeisariyakul ◽  
Kanyanut Narkchamnan ◽  
Boonyakeat Thitisak ◽  
Wonchalerm Rungswang ◽  
Wallace W. Yau
Keyword(s):  
Gel Permeation Chromatography ◽  
Chain Branching ◽  
Long Chain Branching ◽  
Alternative Method ◽  
Gel Permeation ◽  
Long Chain

scholarly journals Influence of Different Types of Peroxides on the Long-Chain Branching of PP via Reactive Extrusion

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 886 ◽  
Author(s):  
Sascha Stanic ◽  
Gergö Gottlieb ◽  
Thomas Koch ◽  
Lukas Göpperl ◽  
Klaus Schmid ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Gel Permeation Chromatography ◽  
Reactive Extrusion ◽  
Chain Branching ◽  
Long Chain Branching ◽  
Single Screw Extruder ◽  
Strength Behavior ◽  
Different Temperatures ◽  
Branched Polypropylene ◽  
Long Chain

Long-chain branching (LCB) is known as a suitable method to increase the melt strength behavior of linear polypropylene (PP), which is a fundamental weakness of this material. This enables the modification of various properties of PP, which can then be used—in the case of PP recyclates—as a practical “upcycling” method. In this study, the effect of five different peroxides and their effectiveness in building LCB as well as the obtained mechanical properties were studied. A single screw extruder at different temperatures (180 and 240 °C) was used, and long-chain branched polypropylene (PP-LCB) was prepared via reactive extrusion by directly mixing the peroxides. The peroxides used were dimyristyl peroxydicarbonate (PODIC C126), tert-butylperoxy isopropylcarbonate (BIC), tert-Butylperoxy 2-ethylhexyl carbonate (BEC), tert-amylperoxy 2-ethylhexylcarbonate (AEC), and dilauroyl peroxide (LP), all with a concentration of 20 mmol/kg. The influence of the temperature on the competitive prevalent reactions of degradation and branching was documented via melt mass-flow rate (MFR), rheology measurements, and gel permeation chromatography (GPC). However, via extensional rheology, strain hardening could be observed in all cases and the mechanical properties could be maintained or even improved. Particularly, PODIC C126 and LP signaled a promising possibility for LCB in this study.

Long Chain Branching in Natural Hevea Rubber-Determination by Gel Permeation Chromatography

1981 ◽  
Vol 54 (1) ◽  
pp. 34-41 ◽  
Author(s):  
J. L. Angulo-Sanchez ◽  
P. Cabaulero-Mata
Keyword(s):  
Molecular Weight ◽  
Soluble Fraction ◽  
Hydroxylamine Hydrochloride ◽  
Gel Permeation Chromatography ◽  
Branch Points ◽  
Long Chain Branching ◽  
Molecular Weights ◽  
Gel Permeation ◽  
The Relationship ◽  
Long Chain

Abstract The hevea brasiltensis rubber contains, besides the insoluble branched entities, linear and branched molecules in the soluble fraction. The branching characteristics found by analyzing fractions of different molecular weight of rubber coagulated from freshly tapped latex, stabilized with hydroxylamine hydrochloride are: (a) molecules with molecular weights above 6.5×104−1.0×105g/mol (depending on the branch points functionality) are branched and molecules below these limits are linear. (b) The relationship between number of branch points and the logarithm of molecular weight is linear. (c) The branching density is not independent of molecular weight, as has been assumed for several polymers, but it has a maximum. The maximum branching density found in the soluble fraction is between 10.2×10−6 and 31.6×10−6mol/g, which varies little with the molecular weight; it is possible that molecular species with higher values become insoluble. (d) Branching results ˜λ and gel content (36%) of the whole rubber gave a total of 93–98% of branched entities (sol and gel) and 2–7% of linear species.

Sign in / Sign up

Export Citation Format

Share Document