Perfluorocyclobutane (PFCB) polymer solutions were subjected to pulsed ultrasound, leading to mechanically induced chain scission and molecular weight degradation. (19)F NMR revealed that the new, mechanically generated end groups are trifluorovinyl ethers formed by cycloreversion of the PFCB groups, a process that differs from thermal degradation pathways. One consequence of the mechanochemica...

Elucidating chemical changes in carbon fiber composites prior to physical degradation has been effectively demonstrated using handheld FTIR analyzers [1]. This application note shows that a handheld infrared spectrometer is equally effective at measuring early onset chemical changes in environmentally stressed PET polymer, which precede cracking and other physical degradation processes. This is...

Commercial initiator – 2,2-dimethoxy-2-phenyl acetophenone (Irgacure 651, Ciba, Switzerland) was introduced to poly(methyl methacrylate) (PMMA) matrix to enhance the polymer degradation. Two types of thin polymeric films (PMMA and PMMA+5% Irgacure) were UV-irradiated in laboratory conditions (Xenon lamp, air atmosphere, room temperature). The photochemical changes in pure PMMA and PMMA doped wi...

The detection of flaws in polymer materials like degradation areas in polymer pipelines in chemical industry, moisture distributions and delaminations in composites used in aircraft industry are today’s challenges of NDT of polymers. New imaging technologies based on electromagnetic waves at high frequencies from 0.05 to 2 THz are promising candidates for polymer testing in the next future. A v...

A critical review: the ring-opening polymerization of cyclic esters provides access to an array of biodegradable, bioassimilable and renewable polymeric materials. Building these aliphatic polyester polymers into larger macromolecular frameworks provides further control over polymer characteristics and opens up unique applications. Polymer stars, where multiple arms radiate from a single core m...

Despite the high efficiency of over 21% reported for emerging thin film perovskite solar cells, one of the key issues prior to their commercial deployment is to attain their long term stability under ambient and outdoor conditions. The instability in perovskite is widely conceived to be humidity induced due to the water solubility of its initial precursors, which leads to decomposition of the p...

Highly adjustable and precisely controllable drug release from a biodegradable stent coating was achieved using a unique family of nanostructured hybrid polyurethanes. These polyurethanes are polyhedral oligosilsesquioxane thermoplastic polyurethanes (POSS TPUs) featuring alternating multiblock structures formed by nanostructured hard segments of POSS and biodegradable soft segments of a polyla...

Chemical degradation of perfluorosulfonic acid (PFSA) membrane is one of the most serious problems for stable and long-term operations of the polymer electrolyte fuel cell (PEFC). The chemical degradation is caused by the chemical reaction between the PFSA membrane and chemical species such as free radicals. Although chemical degradation of the PFSA membrane has been studied by various experime...

Nanotubular clay minerals, composed of aluminosilicate naturally structured in layers known as halloysite nanotubes (HNTs), have a significant reinforcing impact on polymer matrixes. HNTs have broad applications in biomedical applications, the medicine sector, implant alloys with corrosion protection and manipulated transportation of medicines. In polymer engineering, different research studies...

Polymer membranes have been widely used in guided tissue regeneration (GTR) and guided bone regeneration (GBR). In this review, various commercially available membranes are described. Much attention is paid to the recent development of biodegradable polymers applied in GTR and GBR, and the important issues of biodegradable polymeric membranes, including their classification, latest experimental...