نتایج جستجو برای: polymer degradation
تعداد نتایج: 240989 فیلتر نتایج به سال:
Near-infrared spectroscopy (NIRS) and mid-infrared spectroscopy (MIRS) have been used for quantitative and/or qualitative analysis of a wide range of materials. The objective of this study was to investigate the potential of MIRS and NIRS for following the degradation of bio-based food utensils during composting. Polylactide (PLA)-based forks lost 34% of their initial mass and were reduced to s...
Triggerable transient electronics are demonstrated with the use of a metastable poly(phthalaldehyde) polymer substrate and encapsulant. The rate of degradation is controlled by the concentration of the photo-acid generator and UV irradiance. This work expands on the materials that can be used for transient electronics by demonstrating transience in response to a preselected trigger without the ...
Photo-degradation is an irreversible alteration in the chemical, mechanical and physical properties of polymers, these alterations are a result photon absorption from sunlight. UV-light considered to be main factor for initiating photo-degradation process polymers. To extend lifetime their durability, overall minimization rate photo degradation protection polymers against environmental factors,...
in this paper, the focus is on a new kind of biodegradable semi-interpenetrating polymer networks, which derived from ɛ-caprolactone, lactide, 1,4-butane diisocyanate and ethylenediamine and also its potential has been investigated in soft tissue engineering applications. the polymers were characterized by nuclear magnetic resonance (nmr) spectrometry, fourier transform infrared spectroscopy (f...
(1) Understanding the role of peroxide lead free radical attack on the polymer electrolyte at the interface with both anode and cathode electrodes using a specially designed PEM cell enabling accelerated degradation conditions simulating practical H2/Air PEM operation. In this effort the correlation was made with peroxide yield measured directly using RRDE methods with concomitant degradation o...
In this paper, the focus is on a new kind of biodegradable semi-interpenetrating polymer networks, which derived from ɛ-caprolactone, lactide, 1,4-butane diisocyanate and ethylenediamine and also its potential has been investigated in soft tissue engineering applications. The polymers were characterized by nuclear magnetic resonance (NMR) spectrometry, fourier transform infrared spectroscopy (F...
Degradation of the Nafion electrolyte in Proton Exchange Membrane Fuel Cells (PEMFCs) limits the lifetime, motivating development of materials that resist degradation. The mechanism for degradation of Nafion under fuel cell conditions remains uncertain. Studies of Nafion degradation in concentrated OH environments, such as Fenton or vapor HOOH tests, show that the main chain significantly degra...
The photodegradation of polymers has been studied from the early years due to its commercial production. Most plastics are affected by exposure to sunlight in conjunction with other natural weathering forces such as oxygen, water, and heat. Almost all synthetic polymers require stabilization against adverse environmental effects. The consequences of photodegradation depend on the nature of the ...
Herein, new biodegradable star polymer-doxorubicin conjugates designed for passive tumor targeting were investigated, and their synthesis, physico-chemical characterization, drug release, biodegradation, biodistribution and in vivo anti-tumor efficacy are described. In the conjugates, the core formed by poly(amidoamine) (PAMAM) dendrimers was grafted with semitelechelic N-(2-hydroxypropyl)metha...
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