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In a joint theoretical and experimental study, it is shown that the onset of the mechanically‐induced spiropyran (SP) to merocyanine (MC) isomerization can be controlled by both the regiochemistry and the substitution pattern of SP. Four SP‐based bifunctional initiators with consistently varied polymer chain anchor point and substituent are used to synthesize poly‐ε‐caprolactone (PCL). Theoretical calculations (1S and 3S COGEF methods) and in‐situ visible light absorption measurements of films during uniaxial stress–strain experiments consistently show varying activation barriers of the force‐induced ring‐opening reaction of SP to give MC. SPs with PCL chains attached in ortho‐position to the pyran oxygen isomerize at lower stress than their para‐analogs. NO2‐substituted SP mechanophores exhibit a lower activation barrier compared with H‐substituted ones, but only if the NO2 substituent is located in para‐position relative to the O at the pyran half. These results are consistent with theoretical loading rate‐dependent rupture forces required to break the CO bond of SP and may guide mechanophore design. [ABSTRACT FROM AUTHOR]

Diblock copolymers (BCP) with poly(methyl methacrylate) and poly(1H,1H,2H,2H-perfluorodecyl methacrylate) (PsfMA) blocks prepared by anionic polymerization in tetrahydrofuran at −78 °C and atom transfer radical polymerization (ATRP) at 60 °C, respectively, with stepwise varied composition over a wide range in the phase diagram are compared with respect to synthesis limits, phase separation behavior in bulk, and properties of thin films. Both methods yield BCPs with low dispersity (1.1-1.2) at molar masses below 100 kg mol−1. Higher semifluorinated contents can be achieved by ATRP in 1,3-bis(trifluoromethyl)benzene which ensured solubility of PsfMA. BCPs obtained by anionic polymerization show a more distinct phase separation, that is, more regular nanostructures. Additionally, self-organization of the semifluorinated side chains occurs generating smectic layers which alters in turn the BCP morphology especially in thin films as compared to non-semifluorinated BCP. All BCPs show amphiphilic behavior and form micelles in organic solvents which can be used to deposit nanoparticles. [ABSTRACT FROM AUTHOR]

The preparation, characterization, and property evaluation of a series of new semifluorinated polytriazoles (PTEHSH-XX) with various degrees of sulfonation is described. The polymers are synthesized by the click polymerization reaction of a mixture of a new diazide monomer, 1,4-bis-[{2′-trifluromethyl 4′-(4″-azidophenyl)phenoxy}]phenyl, and a sulfonated monomer, 4,4′-diazido-2,2′-stilbenedisulfonic acid disodium salt, with an equimolar amount of a dialkyne monomer, 1,3-diethynylbenzene. The polytriazoles are characterized by Fourier transform infrared spectroscopy (FTIR) and NMR spectroscopic techniques. The polytriazoles show good solubility in selective organic solvents and film forming ability. The films prepared from these polymers show high thermal and chemical stability, low water uptake, high dimensional stability, and excellent mechanical properties. The transmission electron microscopy images of these polymers exhibit a uniformly phase separated morphology. The polymers show very high proton conductivity and the values are within the range of 27-118 mS cm−1 at 30 °C, 53-225 mS cm−1 at 80 °C, and 58-235 mS cm−1 at 90 °C in hydrated condition. [ABSTRACT FROM AUTHOR]

Linear aliphatic copolyesters consisting of the biobased diols ethylene glycol, 1,3-propane diol, and 1,4-butane diol, the biobased dicarboxylic acids succinic acid, adipic acid, and sebacic acid, and a 9,10-dihydro-9-oxa-10-phospha-phenanthren-10-oxide (DOPO)-containing diol or dicarboxylic acid are presented. Structural characteristics of the new copolyesters are studied by 1H and 13C NMR spectroscopy. The influence of chemical composition on the property profile is examined evaluating glass transition temperature Tg, melting behavior, thermal degradation and combustion, mechanical and burning behavior. Incorporation of DOPO monomers suppresses crystallization and yields materials with reduced toughness except in case of sebacates. Tg rises with the content of DOPO monomer. Correlations between the number of methylene groups in the repeating unit and the thermogravimetric analysis degradation maximum, as well as the heat release capacity from pyrolysis combustion flow calorimeter reflect the systematic influence of chemical structure. Copolycondensation with DOPO monomers enhances the limiting oxygen index providing materials with improved overall value. [ABSTRACT FROM AUTHOR]

Comb-like copolymers based on a polyolefin backbone of poly(10-undecene-1-ol) (PUol) with poly(ε-caprolactone) (PCL) side chains are synthesized in two steps. After synthesis of PUol by metallocene-catalyzed polymerization, the side-chain hydroxyl functionalities of this polar polyolefin are used as an initiator for the ring-opening polymerization (ROP) of ε-caprolactone (CL). In this context, copolymers with different lengths of PCL grafts are prepared. The chemical structure and the composition of the synthesized copolymers are characterized by 1H and 13C NMR spectroscopy. It is shown that the hydroxyl end groups of PUol act effectively as initiating sites for the CL ROP. Size-exclusion chromatography (SEC) measurements confirm the absence of non-attached PCL and the expected increase in molar mass after grafting. The thermal and decomposition behaviors are investigated by DSC and thermogravimetric analysis (TGA). The effect of the length of the PCL grafts on the crystallization behavior of the comb-like copolymers is investigated by DSC and wide-angle X-ray scattering (WAXS). [ABSTRACT FROM AUTHOR]

The preparation and characterization of a series of poly(methyl methacrylate)- block-poly(butyl acrylate)- block-poly(methyl methacrylate) ABA triblock copolymers and their clay nanocomposites via in situ ATRP is reported. The molecular weights and the chemical structures of these nanocomposites are characterized by means of GPC, FTIR, and NMR analyses. DSC, AFM, and SAXS analyses prove a nanophase-separated morphology in the block copolymer/clay nanocomposites. DMA analysis demonstrates an additional reinforcing effect of nanoclay in the block copolymer nanocomposites. AFM analysis indicates that the bulk polymer has a cylindrical morphology that is unaffected in the nanocomposite, as corroborated by SAXS analysis. [ABSTRACT FROM AUTHOR]