Oxidative degradation and morphological properties of gamma‐irradiated isotactic polypropylene films

2017 ◽  
Vol 12 (7) ◽  
pp. 478-481 ◽  
Author(s):  
Sarah Mouaci ◽  
Mohamed Saidi ◽  
Nadia Saidi‐Amroun
Keyword(s):  
Isotactic Polypropylene ◽  
Oxidative Degradation ◽  
Morphological Properties ◽  
Polypropylene Films ◽  
Gamma Irradiated

scholarly journals Facile Synthesis of L-Cysteine Functionalized Graphene Quantum Dots as a Bioimaging and Photosensitive Agent

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1879
Author(s):  
Mila Milenković ◽  
Aleksandra Mišović ◽  
Dragana Jovanović ◽  
Ana Popović Bijelić ◽  
Gabriele Ciasca ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Gamma Irradiation ◽  
Hela Cells ◽  
Graphene Quantum Dots ◽  
Morphological Properties ◽  
Paramagnetic Resonance ◽  
Chemical Reagents ◽  
Amino Amide ◽  
Gamma Irradiated ◽  
Electron Paramagnetic

Nowadays, a larger number of aggressive and corrosive chemical reagents as well as toxic solvents are used to achieve structural modification and cleaning of the final products. These lead to the production of residual, waste chemicals, which are often reactive, cancerogenic, and toxic to the environment. This study shows a new approach to the modification of graphene quantum dots (GQDs) using gamma irradiation where the usage of reagents was avoided. We achieved the incorporation of S and N atoms in the GQD structure by selecting an aqueous solution of L-cysteine as an irradiation medium. GQDs were exposed to gamma-irradiation at doses of 25, 50 and 200 kGy. After irradiation, the optical, structural, and morphological properties, as well as the possibility of their use as an agent in bioimaging and photodynamic therapy, were studied. We measured an enhanced quantum yield of photoluminescence with the highest dose of 25 kGy (21.60%). Both S- and N-functional groups were detected in all gamma-irradiated GQDs: amino, amide, thiol, and thione. Spin trap electron paramagnetic resonance showed that GQDs irradiated with 25 kGy can generate singlet oxygen upon illumination. Bioimaging on HeLa cells showed the best visibility for cells treated with GQDs irradiated with 25 kGy, while cytotoxicity was not detected after treatment of HeLa cells with gamma-irradiated GQDs.

Morphology and mechanical properties of transcrystalline isotactic polypropylene

e-Polymers ◽  
2003 ◽  
Vol 3 (1) ◽  
Author(s):  
Koh-hei Nitta ◽  
Yoshikazu Yamamoto
Keyword(s):  
Mechanical Properties ◽  
Isotactic Polypropylene ◽  
Mechanical Energy ◽  
Supermolecular Structure ◽  
The Other ◽  
Morphological Properties ◽  
Spherulitic Morphology ◽  
Other Hand ◽  
Morphology And Mechanical Properties ◽  
Yielding Process

Abstract We examined mechanical and morphological properties of fully transcrystalline polypropylene grown from the surface of poly(tetrafluoroethylene) sheets. Comparison of mechanical properties between transcrystalline and spherulitic polypropylenes demonstrated that Young’s modulus is dependent on the crystallinity and independent of the supermolecular structure. On the other hand, the mechanical yielding process was predominantly affected by the supermolecular structure, and the mechanical energy required for yielding of transcrystalline sheets was greater than that of the spherulitic morphology. In addition, it was found that mechanical necking is required for the alignment of lamellae in the stretching direction. This means that the unfolding process of lamellae orienting in the stretching direction is associated with necking and ductility.

Characterization of orientation of one-way and two-way drawn isotactic polypropylene films

Polymer ◽  
1993 ◽  
Vol 34 (13) ◽  
pp. 2691-2701 ◽  
Author(s):  
I. Karacan ◽  
A.K. Taraiya ◽  
D.I. Bower ◽  
I.M. Ward
Keyword(s):  
Isotactic Polypropylene ◽  
Polypropylene Films
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