Selective Localization of MWCNT in Poly (Trimethylene Terephthalate)/Poly Ethylene Blends: Theoretical Analysis, Morphology, and Mechanical Properties

2018 ◽  
Vol 381 (1) ◽  
pp. 1800104 ◽  
Author(s):  
Aswathi M. Kunjappan ◽  
Ajitha A. Ramachandran ◽  
Moothetty Padmanabhan ◽  
Lovely P. Mathew ◽  
Sabu Thomas
Keyword(s):  
Mechanical Properties ◽  
Theoretical Analysis ◽  
Selective Localization ◽  
Trimethylene Terephthalate ◽  
Poly Ethylene ◽  
Morphology And Mechanical Properties

scholarly journals Electrospun Alginate Fibers: Mixing of Two Different Poly(ethylene oxide) Grades to Improve Fiber Functional Properties

Nanomaterials ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 971 ◽  
Author(s):  
Barbara Vigani ◽  
Silvia Rossi ◽  
Giulia Milanesi ◽  
Maria Bonferoni ◽  
Giuseppina Sandri ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Ethylene Oxide ◽  
Electrospinning Process ◽  
Mechanical Resistance ◽  
Fiber Morphology ◽  
Chain Entanglement ◽  
Poly Ethylene Oxide ◽  
Alginate Fibers ◽  
Poly Ethylene ◽  
Morphology And Mechanical Properties

The aim of the present work was to investigate how the molecular weight (MW) of poly(ethylene oxide) (PEO), a synthetic polymer able to improve alginate (ALG) electrospinnability, could affect ALG-based fiber morphology and mechanical properties. Two PEO grades, having different MWs (high, h-PEO, and low, l-PEO) were blended with ALG: the concentrations of both PEOs in each mixture were defined so that each h-PEO/l-PEO combination would show the same viscosity at high shear rate. Seven ALG/h-PEO/l-PEO mixtures were prepared and characterized in terms of viscoelasticity and conductivity and, for each mixture, a complex parameter rH/rL was calculated to better identify which of the two PEO grades prevails over the other in terms of exceeding the critical entanglement concentration. Thereafter, each mixture was electrospun by varying the process parameters; the fiber morphology and mechanical properties were evaluated. Finally, viscoelastic measurements were performed to verify the formation of intermolecular hydrogen bonds between the two PEO grades and ALG. rH/rL has been proved to be the parameter that better explains the effect of the electrospinning conditions on fiber dimension. The addition of a small amount of h-PEO to l-PEO was responsible for a significant increase in fiber mechanical resistance, without affecting the nano-scale fiber size. Moreover, the mixing of h-PEO and l-PEO improved the interaction with ALG, resulting in an increase in chain entanglement degree that is functional in the electrospinning process.

scholarly journals Study of microstructure modification on La0.7Sr0.3Co0.2Fe0.8O3-δ (LSCF 7328) asymmetric flat membrane

2019 ◽  
Vol 15 (4) ◽  
pp. 498-503
Author(s):  
Silvana Dwi Nurherdiana ◽  
Naimatul Khoiroh ◽  
Ahyudia Malisa Ilham ◽  
Rendy Muhamad Iqbal ◽  
Wahyu Prasetyo Utomo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Average Pore Size ◽  
Morphological Evidence ◽  
Inversion Method ◽  
Dense Layer ◽  
Sem Images ◽  
Average Pore ◽  
Poly Ethylene ◽  
Morphology And Mechanical Properties

The LSCF 7328 (La0.7Sr0.3Co0.2Fe0.8O3-δ) asymmetric flat membranes were successfully prepared via a phase-inversion method followed by sintering at 1200 °C. In this study, a variety of poly(ethylene glycol) (PEGs) as the pore-forming agent, with  3 wt% composition and a wide ranges of molecular weight (Mw) (200 to 8000 Da) were used to tests its’ effect to the properties of LSCF  membranes. The results show that the PEGs, as additives, were able to modify the pore morphology and mechanical properties of the LSCF 7328 membrane. The morphological evidence from SEM images showed that the LSCF membranes have an asymmetric configuration, comprised of sponge-like and finger-like pores which are integrated with a dense layer. The variation in average pore size is clearly seen, starting from 13.00 to 135.33 μm, following the increase in PEGs molecular weight. The LSCF membranes which were prepared using PEG additive have higher hardness (1.2 – 13.6 Hv) than the membrane with no PEG  (0.2 Hv). In contrast, the porosity and pore volume of the membranes decrease with the increase of PEGs molecular weight. The decrease might be due to the formation of various closed macro-voids as the molecular weight of PEGs increases. Furthermore, the thermal expansion coefficient of the membrane with different PEGs molecular weight (ie. 400, 600, 4000 and 6000) Da posses no significant different, i.e. around 16 x 10-6 °C-1, although the membrane showed different morphology and mechanical properties.

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