Review of Progress in Shape Memory Epoxies and Their Composites

Shape memory polymer (SMP) is capable of memorizing one or more temporary shapes and recovering successively to the permanent shape upon various external stimuli. Beside of the above mentioned one-way variants, also two-way shape memory polymers (SMPs) and shape memory (SM) systems exist which feature a reversible shape change on the basis of “on-off switching” of the external stimulus. The preparation, properties and modelling of shape memory epoxy resins (SMEP), SMEP foams and composites have been surveyed in this exhaustive review article. The underlying mechanisms and characteristics of SM were introduced. Emphasis was put to show new strategies on how to tailor the network architecture and morphology of EPs to improve their SM performance. To produce SMEPs novel preparation techniques, such as electrospinning, ink printing, solid-state foaming, were tried. The potential of SMEPs and related systems as multifunctional materials has been underlined. Added functionality may include, among others, self-healing, sensing, actuation, porosity control, recycling. Recent developments in the modelling of SMEPs were also highlighted. Based on the recent developments some open topics were deduced which are merit of investigations in future works

Atmospheric Pressure Photoionization Mass Spectrometry of Polyisobutylene Derivatives

Atmospheric pressure photoionization mass spectrometric (APPI-MS) study on three types of polyisobutylene derivatives is reported. Two of the polyisobutylenes investigated were polyisobutylene with dihydroxy and diolefinic end-groups derived from aromatic moieties [dicumyl chloride, 1,4-bis(2-chloro-2-propyl)benzene], and the third contained no aromatic moieties with a monohydroxy end-group. All three polyisobutylene derivatives (PIBs) had an average molecular weight (Mn) of ∼2000 g/mol, with a polydispersity lower than 1.2. In the positive ion APPI mode, protonated PIB molecules were formed, but the molecular weights obtained were considerably lower than those expected, indicating fragmentation of the PIB chains. In the negative APPI mode, using solvents such as tetrahydrofuran and toluene as dopants, no signal was obtained. However, in chlorinated solvents, such as CCl4, CHCl3, and CH2Cl2, in the presence of toluene dopant, PIB adducts with chloride ions were formed with relatively high signal intensity. In the case of CH2Cl2, no dopant (toluene) was necessary to generate chlorinated adduct ions, albeit increasing the toluene concentration in the flow increased the PIB signal intensity. The effect of the toluene concentration on PIB signal intensity was studied and models that include (1) photoionization of toluene, (2) formation of chloride ions from the chlorinated solvents by dissociative electron capture, (3) formation of chlorinated adduct ions and charge recombination reactions between the toluene radical cation, (4) chloride ions, and (5) chlorinated adduct ions are proposed based on the experimental results

Kopolimer tömegspektrumok automatikus kiértékelése: Automatic evaluation of copolymer mass spectra

In our work, the primary goal was to develop an appropriately flexible automated algorithm for mass spectrometric analysis of copolymer systems. To solve the problem, it was necessary to model the appropriate isotope distribution, to develop a stable method to find non-isotope peaks and to solve the original mass spectrum as well as to identify the unknown peaks. After identification, the correct subroutines to calculate additional information parameters was programmed. All mass spectra were tested using the theoretical spectra and our measured b-ethylene-glycol-b-propylene glycol copolymer systems.  Kivonat Munkánk során az elsődleges cél az volt, hogy egy megfelelően rugalmas automata algoritmust dolgozzunk ki kopolimer rendszerek tömegspektrumának analízisére. A feladat megoldásához szükség volt a megfelelő izotóp eloszlás modellezésére, egy stabil módszer fejlesztésére a nem izotóp csúcsok azonosításához, az eredeti tömegspektrum és az azonosított csúcsok kezelésének megoldására. Ezt követően alkalmas szubrutinok állítottunk elő a további információt hordozó paraméterek kiszámításához. Mindezt elméleti és általunk mért b-etilén-glikol-b-propilén-glikol kopolimer rendszerekkel teszteltük. &nbsp

Creep and Quasi-Relaxation Examination of Artificially Aged Plasticized PVC

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Többlépéses tömegmaradék analízis alkalmazása kopolimerek tandem tömegspektrumainak elemzésére: Application of Multistep Mass-Remainder Analysis for the evaluation copolymer tandem mass spectra

Polyalkylene oxide polyether polyols are widely used in polymer industry as high-performance coating, wetting, crosslinking agents. Therefore, their characterization plays a very important role in quality management. We applied the recently invented three-step MARA method in order to evaluate complex tandem mass spectra of polyether polyols. The obtained peak series were distinguished and further structural information was gained on multi-arm copolymers. M-MARA (Multistep Mass-remainder analysis) yields an ultra-simplified graphical representation of the MS/MS spectra and sorts the product ions based on their double bond equivalent (DBE) values, where six-arm, three-arm and linear diol polyether polyols demonstrates 0-4, 0-2 and 0-1 DBE values, respectively.  Kivonat A poliéter poliolokat az iparban széles körben alkalmazzák, mint bevonatok, nedvesítő vagy térhálósító szerek. Ezért, ezek karakterizálása, kiemelt jelentőségű minőség-ellenőrzés szempontjából. Munkánk során a több lépéses Tömegmaradék Analízist alkalmaztuk poliéterek komplex tandem tömegspektrumainak értékelésére. Az M-MARA (Több lépéses Tömegmaradék Analízis) módszerrel a detektált csúcs sorozatokat megkülönböztettük és további szerkezeti információkat kaptunk. A mérésekből előállított ábrák egyszerű reprezentációi a tandem tömegspektrumoknak, melyen a termék ionok a kettőskötések száma alapján rendeződnek. A hatkarú, háromkarú és lineáris polimerek 0-4, 0-2, 0-1 DBE értékű sorozatokkal jellemezhetők. &nbsp

One-Pot Synthesis and Characterization of Novel Shape-Memory Poly(?-Caprolactone) Based Polyurethane-Epoxy Co-networks with Diels-Alder Couplings

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New blue light-emitting isocyanobiphenyl based fluorophores: Their solvatochromic and biolabeling properties

The preparation and optical study of 4-amino-4′-isocyanobiphenyl (ICAB) and its mono-and dialkylated derivatives (monoMICAB and diMICAB) are reported. They were found to be effective blue light emitters with a solvatochromic range of Δλmax = 104 nm, 92 nm and 90 nm, respectively. All three compounds turned out to be promising candidates in protein-labeling, yielding ∼70-190× increase in their fluorescence intensity when mixed with 10× molar excess of bovine serum albumin (BSA). The binding constants for the BSA-fluorophore complexes were found to be KICAB-BSA = 3.8 × 104 ± 5.7 × 103 M-1, KmonoMICAB-BSA = 6.0 × 104 ± 3.9 × 103 M-1 and KdiMICAB-BSA = 2.3 × 104 ± 3.2 × 103 M-1. Time resolved fluorescence measurements revealed a nearly uniform ∼2 ns lifetime for all three BSA-complexed ICAB derivatives. © 2015 Elsevier B.V. All rights reserved