Free volume as an internal material parameter to probe interfaces in ternary polymer blends: A positron lifetime study

2013 ◽  
Vol 130 (5) ◽  
pp. 3335-3344 ◽  
Author(s):  
Meghala Dinesh ◽  
Ranganathaiah Chikkakuntappa
Keyword(s):  
Polymer Blends ◽  
Free Volume ◽  
Material Parameter ◽  
Positron Lifetime ◽  
Ternary Polymer

An effective tool to characterize adhesion at the interface of binary polymer blends: a free volume study

2011 ◽  
Vol 31 (2-3) ◽  
Author(s):  
Jaya Madhu Raj ◽  
Abdullah Mohammed Ali Mohammed Altaweel ◽  
Malavalli Nagarajaiah Chandrashekara ◽  
Puttegowda Ramya ◽  
Harijan Basavaraju Ravikumar ◽  
...  
Keyword(s):  
Polymer Blends ◽  
Free Volume ◽  
Hydrodynamic Interaction ◽  
Positron Lifetime ◽  
Volume Data ◽  
Hydrogen Bond Formation ◽  
Binary Polymer ◽  
Interfacial Modification ◽  
Microwave Irradiations ◽  
Partially Miscible

Abstract In this work, an effective method of characterizing the adhesion at the interface of partially miscible and immiscible binary polymer is used. Three polymer blends namely PS/PMMA, PP/NBR and PVC/SAN were irradiated with e-beam and microwaves, in order to bring about interfacial modification, and were characterized in terms of free volume measured by Positron Lifetime technique. The changes in free volume parameters upon e-beam and microwave irradiation on the two systems clearly shows improved interaction between the blend constituents as a result of cross-linking through hydrogen bond formation. However, the extent of interfacial modification brought in at different weight compositions is not forthcoming. Therefore, the hydrodynamic interaction parameter α, which accounts for friction at the interface between the dissimilar chains of the blend constituents, is evaluated from the very same free volume data. Since α represents the strength of hydrodynamic interaction, it could be taken as an indicator of the adhesion strength at the interface. Present results showed that both e-beam and microwave irradiations can be used to stabilize the interfaces in binary polymer blends as evidenced by hydrodynamic interaction.

Characterization of interfacial adhesion in binary polymer blends: a new approach based on positron lifetime study

2011 ◽  
Vol 31 (2-3) ◽  
Author(s):  
Chikkakuntappa Ranganathaiah
Keyword(s):  
Polymer Blends ◽  
Free Volume ◽  
Hydrodynamic Interaction ◽  
Positron Lifetime ◽  
Volume Data ◽  
New Approach ◽  
Polar Groups ◽  
Binary Polymer ◽  
Partially Miscible

Abstract A new method of characterizing the adhesion at the interface of partially miscible and immiscible binary polymer blends based on free volume concept is described here. The efficacy of the method is tested in four binary polymer blend systems namely PS/PMMA, PVC/EVA, PP/NBR and PVC/SAN. The usefulness of hydrodynamic interaction is exploited which is derived from free volume data to understand the changes at the interface. We understand that if the adhesion at the interface is good it exhibits large negative values for hydrodynamic interaction parameter α, a measure of excess friction at the interface. The thermal properties (indicated by Tg) also improve for this condition. To show that the method is sensitive to the changes at the interface, we modified the interface through microwave and e-beam irradiation and found from α characterization, that blends with polar groups exhibit interface stabilization for microwave irradiation while e-beam is good for blends with no polar or weak polar groups.

Mechanical and microstructural properties of polystyrene based composites: positron lifetime spectroscopic and DSC studies

2011 ◽  
Vol 31 (2-3) ◽  
Author(s):  
Abdullah Mohammed Ali Mohammed Altaweel ◽  
Jaya Madhu Raj ◽  
Malalvalli Nagarajaiah Chandrashekara ◽  
Puttegowda Ramya ◽  
Parthasarathy Sampathkumaran ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Free Volume ◽  
Positron Lifetime ◽  
Tensile Modulus ◽  
Silica Content ◽  
Scanning Calorimetry ◽  
Dsc Studies ◽  
Microstructural Property ◽  
Calcium Aluminosilicate

Abstract Polystyrene (PS) based composites respectively with cenosphere (CS) and calcium aluminosilicate (CAS) as fillers were studied using the positron lifetime technique to reveal the correlation between free volume, a microstructural property, and mechanical properties of the composites (tensile strength and tensile modulus). The thermal stability of the composites was determined using differential scanning calorimetry. The results showed that addition of CAS filler lead to a significant improvement in the mechanical properties of the composite, whereas addition of CS resulted in improvement in tensile modulus only. Both PS/CAS and PS/CS composites showed enhancement in thermal stability compared with that of the pure PS matrix. The positron results showed that the average free volume size for the PS/CAS composite (at 40 phr CAS) was reduced significantly compared with that of the pure PS. These results are understood in terms of the influence of silica content, filler-matrix interaction, and particle size.

Preliminary Positron Lifetime Results on Free Volumes in Cyclodextrins

2010 ◽  
Vol 666 ◽  
pp. 99-102 ◽  
Author(s):  
Maria Fatima Ferreira Marques ◽  
A.M.G. Moreira Da Silva ◽  
P.M. Gordo ◽  
Z. Kajcsos
Keyword(s):  
Positron Annihilation ◽  
Free Volume ◽  
Positron Lifetime ◽  
Positron Annihilation Lifetime Spectroscopy ◽  
Positron Source ◽  
Lifetime Component ◽  
Positron Annihilation Lifetime ◽  
Long Lifetime

Positron annihilation lifetime spectroscopy was used to study the free-volume parameters in various pure -, - and -cyclodextrins samples and, in the case of β-cyclodextrin, with inclusion of S-carvone and thymoquinone. The results clearly indicate the presence of long lifetime components related to Ps-formation. The data show that the addition of S-carvone to β-cyclodextrin results in a decrease of o-Ps lifetime that we ascribe to a reduction of free volume holes from 81.8 to 63.7 Å3. The long lifetime component disappears when thymoquinone is added to -cyclodextrin, indicating this substance acts as an o-Ps quencher. For all samples studied, a decrease in the long lifetime component values was observed with increasing source in situ time, a result that might be attributed to the irradiation of the sample by the 22Na positron source.

Miscibility Study of Polymer Blends Composed of Polyethylenimine, Polyethyleneglycol, and Carboxymethyl Chitosan

2011 ◽  
Vol 284-286 ◽  
pp. 1707-1712 ◽  
Author(s):  
Yong Sheng Chen ◽  
Jiang Nan Shen ◽  
Jun Hong Qiu
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Polymer Blends ◽  
Carboxymethyl Chitosan ◽  
Dilute Solution ◽  
Poly Ethylene Glycol ◽  
Poly Ethylene ◽  
Ternary Polymer ◽  
Dilute Solution Viscometry ◽  
Scanning Electron

Miscibility of ternary polymer blends composed of poly(ethyleneimine) (PEI), poly(ethylene glycol) (PEG), and carboxymethyl chitosan (CMCS) was investigated by dilute-solution viscometry, FTIR spectrum, and scanning electron microscope (SEM) techniques. The results of these measurements indicate that PEG is immiscible in the ternary CMCS/PEI/PEG polymer blend.

Sign in / Sign up

Export Citation Format

Share Document